An immunotoxin composed of an antibody to the human transferrin receptor (454A12) and ricin A cha... more An immunotoxin composed of an antibody to the human transferrin receptor (454A12) and ricin A chain (RTA) was shown to inhibit the growth of M11:()\ ( VR-3 tumors in a nude mouse model of human ovarian cancer. Inhibition of tumor growth by 454A12-RTA was related to the dose administered. The antitumor activity of the immunotoxin was blocked by coinjection of
The glutathione transferases comprise a family of isoenzymes, one or more of which are involved i... more The glutathione transferases comprise a family of isoenzymes, one or more of which are involved in the conjugation of alkylating agents to glutathione (GSH). Increased GSH transferase activity has been shown to underlie acquired resistance to several alkylating agents. Ethacrynic acid inhibits the isoenzymes of GSH transferase with 50% inhibitory- concentration values ranging from 0.3 to 6.0 MMand has been
The role of glutathione (GSH) in tumor cell resistance to alkylating agents and platinum compound... more The role of glutathione (GSH) in tumor cell resistance to alkylating agents and platinum compounds is suggested by a body of laboratory and clinical studies. The rate-limiting enzyme in GSH synthesis is y-glutamyl- cysteine synthetase (y-GCS), the expression of which is proportional both to GSH content and to the level of resistance in ovarian cancer cell lines. The role of
We have examined 41 forms of ovarian cancer for genetic alterations on chromosome 9 using a combi... more We have examined 41 forms of ovarian cancer for genetic alterations on chromosome 9 using a combination of five RFLP DNA probes and 15 simple tandem repeat polymorphisms. Genetic imbalance (i.e., loss of heterozygosity, microsatellite instability, amplification) for 1 or more informative markers on chromosome 9 was observed in 66% (27 of 41) of our tumor panel. Genetic imbalance was observed on 9q in 59% (24 of 41) of tumors informative for at least one locus. In contrast, only 13% (5 of 40) of informative tumors demonstrated a genetic alteration involving 9p. Furthermore, allelic loss on 9q was more common in late stage tumors (63%, 17 of 27) and poorly differentiated tumors (75%, 15 of 20) as compared to benign and early stage tumors (30%, 3 of 10). Evaluation of 15 tumors showing limited regions of genetic imbalance has identified 2 candidate tumor suppressor regions on 9q and 1 on 9p. Interestingly, the regions defined to 9p21-p24, 9q31, and 9q32-q34 all overlap with several kno...
The optimum integration of chemotherapy and irradiation is of potential clinical significance in ... more The optimum integration of chemotherapy and irradiation is of potential clinical significance in the treatment of ovarian cancer. A series of human ovarian cancer cell lines have been developed in which dose-response relationships to standard anticancer drugs have been determined, and the patterns of cross-resistance between these drugs and irradiation have been established. By stepwise incubation with drugs, sublines of A2780, a drug-sensitive cell line, have been made 100-fold, 10-fold, and 10-fold more resistant to Adriamycin (2780AD), melphalan (2780ME), and cisplatin (2780CP). Two additional cell lines, NIH:OVCAR-3nu(Ag+) and NIH:OVCAR-4(Ag+), were established from drug-refractory patients. 2780ME, 2780CP, OVCAR-3nu(Ag+), and OVCAR-4(Ag+) are all cross-resistant to irradiation, with DOS of 146, 187, 143, and 203, respectively. However, 2780AD remains sensitive to radiation, with a DO of 111, which is similar to that of A2780 (101). Glutathione (GSH) levels are elevated in 2780M...
A human ovarian cancer cell line, A2780, derived from an untreated ovarian cancer patient and rel... more A human ovarian cancer cell line, A2780, derived from an untreated ovarian cancer patient and relatively sensitive to cisplatin was treated by stepwise incubation with cisplatin to produce a cisplatin-resistant variant, 2780CP. The relative abilities of these cell lines to repair cisplatin-induced damage to cellular DNA then was examined by measure of [3H]thymidine incorporation into normal density DNA separated from bromodeoxyuridine-substituted DNA on alkaline cesium chloride gradients. These studies revealed that primary cisplatin resistance present in 2780CP was associated with a near twofold-increased ability to repair damage induced by the drug under conditions where 2780CP was approximately 5-fold resistant to cisplatin. Aphidicolin, a specific inhibitor of DNA polymerase alpha, showed a dose-dependent capacity to inhibit DNA repair in this system with maximum inhibition of 63% at 4 micrograms/ml. It was also found that inhibition of DNA repair during and shortly after cispla...
Single-agent chemotherapy with cisplatin or carboplatin can induce remissions in approximately 30... more Single-agent chemotherapy with cisplatin or carboplatin can induce remissions in approximately 30% of previously treated patients with advanced stage ovarian cancer. Previous studies have shown that the extent of platinum-DNA adduct formation measured in WBC DNA of ovarian cancer patients treated with cisplatin or carboplatin is directly associated with disease response (Reed et al., Proc. Natl. Acad. Sci. USA, 84: 5024-5028, 1987). It has been unclear whether adduct level in WBC DNA is independent of known prognostic variables in this disease, or whether adduct level parallels a known prognostic variable that can be more easily monitored. In a cohort of 24 ovarian cancer patients treated with single-agent cisplatin or carboplatin, we retrospectively assessed the relationship between disease response, platinum-DNA adducts in WBC DNA, and each of eight prognostic variables by both univariate analysis and multivariate analysis. The prognostic variables evaluated included: response to ...
Journal of clinical oncology : official journal of the American Society of Clinical Oncology, 2003
In randomized trials the combination of cisplatin and paclitaxel was superior to cisplatin and cy... more In randomized trials the combination of cisplatin and paclitaxel was superior to cisplatin and cyclophosphamide in advanced-stage epithelial ovarian cancer. Although in nonrandomized trials, carboplatin and paclitaxel was a less toxic and highly active combination regimen, there remained concern regarding its efficacy in patients with small-volume, resected, stage III disease. Thus, we conducted a noninferiority trial of cisplatin and paclitaxel versus carboplatin and paclitaxel in this population. Patients with advanced ovarian cancer and no residual mass greater than 1.0 cm after surgery were randomly assigned to receive cisplatin 75 mg/m2 plus a 24-hour infusion of paclitaxel 135 mg/m2 (arm I), or carboplatin area under the curve 7.5 intravenously plus paclitaxel 175 mg/m2 over 3 hours (arm II). Seven hundred ninety-two eligible patients were enrolled onto the study. Prognostic factors were similar in the two treatment groups. Gastrointestinal, renal, and metabolic toxicity, as w...
We have previously obtained, by exposure to near continuous increas ing concentrations of cisplat... more We have previously obtained, by exposure to near continuous increas ing concentrations of cisplatin, a panel of human ovarian cancer cell lines that exhibit a wide range of primary resistance to the drug (9- to >400- fold). These cells had strikingly increased (4- to 50-fold) levels of gluta- thione (GSH) as compared with the drug-sensitive cells of origin (A. K.
Phosphonacetyl-l-aspartate (PALA), an inhibitor of aspartate transcarbamylase that depletes uridi... more Phosphonacetyl-l-aspartate (PALA), an inhibitor of aspartate transcarbamylase that depletes uridine nucleotide pools, selectively potentiates the antitumor activity of 5-fluorouracil (5-FU) in preclinical models. Due to the promising results we obtained using PALA/5-FU in colorectal cancer, we performed a phase II trial in patients presenting with advanced pancreatic cancer. PALA was given intravenously at 250 mg/m2 on day 1, followed 24
Proceedings of The National Academy of Sciences, 1987
Fifty-five ovarian cancer patients receiving platinum drug-based chemotherapy have been studied p... more Fifty-five ovarian cancer patients receiving platinum drug-based chemotherapy have been studied prospectively to determine the extent of formation of the bidentate intrastrand adducts of diammineplatinum covalently attached to the N7 positions of adenosine and/or guanosine in leukocyte DNA. Data for clinical response, obtained from medical records, were then correlated with the adduct values. Patients were treated with platinum-based single-agent or
A series of cisplatin-resistant cell lines were used to examine the formation and removal of plat... more A series of cisplatin-resistant cell lines were used to examine the formation and removal of platinum-DNA adducts from the overall genome and the formation and removal of cisplatin-interstrand cross-links from specific genomic regions. Cisplatin accumulation and DNA platination levels, which correlated linearly, were similar in three of the resistant cell lines despite differences in their primary cisplatin resistance. Increased platinum removal from total genomic DNA was found to be associated with increased resistance. Interstrand cross-link levels were found to be 2- to 4-fold lower in the 28S ribosomal RNA gene and a non-coding genomic region of the resistant cell lines as compared with the parental A2780 cell line. In addition, 1.2- to 2.7-fold more cross-links were formed in the non-coding region than in the ribosomal RNA gene in all of the cell lines. Interstrand cross-links were removed more rapidly from both regions of the highly cisplatin-resistant C80 and C200 cells and from the ribosomal RNA gene only in the cell lines of lower resistance. The results support a role for DNA repair and alterations in interstrand cross-link formation in cisplatin resistance and provide evidence for heterogeneous interstrand cross-link formation in the genome.
Epithelial ovarian cancer is neither a common nor a rare disease. In the United States, the preva... more Epithelial ovarian cancer is neither a common nor a rare disease. In the United States, the prevalence of ovarian cancer in postmenopausal women (1 in 2,500) significantly affects strategies for prevention and detection. If chemoprevention for ovarian cancer were provided to all women over the age of 50, side effects would have to be minimal in order to achieve an acceptable ratio of benefit to risk. This ratio might be improved by identifying subsets of individuals at increased risk or by bundling prevention of ovarian cancer with treatment for other more prevalent conditions. Approximately 10% of ovarian cancers are familial and relate to mutations of BRCA1, BRCA2, and mismatch repair genes. More subtle genetic factors are being sought in women with apparently sporadic disease. Use of oral contraceptive agents for as long as 5 years decreases the risk of ovarian cancer in later life by 50%. In one study, fenretinide (4-HPR) delayed development of ovarian cancer in women at increased risk of developing breast and ovarian cancer. Accrual to confirmatory studies has been prohibitively slow and prophylactic oophorectomy is recommended for women at increased genetic risk. Vaccines may have a role for prevention of several different cancers. Breast and ovarian cancers express mucins that could serve as targets for vaccines to prevent both cancers. Early detection of ovarian cancer requires a strategy with high sensitivity (> 75% for stage I disease) and very high specificity (> 99.6%) to achieve a positive predictive value of 10%. Transvaginal sonography (TVS) has achieved these values in some studies, but is limited by the cost of annual screening in a general population. Two-stage strategies that incorporate both serum markers and TVS promise to be more cost-effective. An algorithm has been developed that calculates risk of ovarian cancer based on serial CA125 values and refers patients at highest risks for TVS. Use of the algorithm is currently being evaluated in a trial with 200,000 women in the United Kingdom that will critically test the ability of a two-stage screening strategy to improve survival in ovarian cancer. Whatever the outcome, additional serum markers will be required to detect all patients in an initial phase of screening. More than 30 serum markers have been evaluated alone and in combination with CA125. Recent candidates include: HE4, mesothelin, M-CSF, osteopontin, kallikrein(s) and soluble EGF receptor. Proteomic approaches have been used to define a distinctive pattern of peaks on mass spectroscopy or to identify a limited number of critical markers that can be assayed by more conventional methods. Several groups are placing known markers on multiplex platforms to permit simultaneous assay of multiple markers with very small volumes of serum. Mathematical techniques are being developed to analyze combinations of marker levels to improve sensitivity and specificity. In the future, serum markers should improve the sensitivity of detecting recurrent disease as well as facilitate earlier detection of ovarian cancer.
Human ovarian cancer cell lines with stable cisplatin resistance have been developed by chronic e... more Human ovarian cancer cell lines with stable cisplatin resistance have been developed by chronic exposure of the parent cisplatin-sensitive A27X0line to increasing concentrations of cisplatin. 2780eâ"¢ (CP8 refers to this cell line's growth in medium containing 8 MM cisplatin) has several clonal cytogenetic abnormalities but lacks homogeneously staining re gions or double-minute chromosomes. It has a significantly greater mon- olayer
The effectiveness of adriamycin in the treatment of ovarian cancer and other human tumors has bee... more The effectiveness of adriamycin in the treatment of ovarian cancer and other human tumors has been limited by the development of drug resistance. Verapamil, a calcium channel blocking agent, completely reversed adriamycin resistance in human ovarian cancer cells with moderate (three- to sixfold) degrees of resistance and partially reversed resistance in highly (150-fold) resistant cells. The potentiating effect of verapamil was due to inhibition of adriamycin efflux in the resistant cells. These results have led to a clinical trial of adriamycin and verapamil in refractory ovarian cancer patients.
A MESSAGE FROM ASCO&a... more A MESSAGE FROM ASCO'S PRESIDENT: For the third year, the American Society of Clinical Oncology (ASCO) is publishing Clinical Cancer Advances: Major Research Advances in Cancer Treatment, Prevention, and Screening, an annual review of the most significant cancer research presented or published over the past year. ASCO publishes this report to demonstrate the important progress being made on the front lines of clinical cancer research today. The report is intended to give all those with an interest in cancer care-the general public, cancer patients and organizations, policymakers, oncologists, and other medical professionals-an accessible summary of the year's most important cancer research advances. These pages report on the use of magnetic resonance imaging for breast cancer screening, the association between hormone replacement therapy and breast cancer incidence, the link between human papillomavirus and head and neck cancers, and the use of radiation therapy to prevent lung cancer from spreading. They also report on effective new targeted therapies for cancers that have been historically difficult to treat, such as liver cancer and kidney cancer, among many others. A total of 24 advances are featured in this year's report. These advances and many more over the past several years show that the nation's long-term investment in cancer research is paying off. But there are disturbing signs that progress could slow. We are now in the midst of the longest sustained period of flat government funding for cancer research in history. The budgets for the National Institutes of Health and the National Cancer Institute (NCI) have been unchanged for four years. When adjusted for inflation, cancer research funding has actually declined 12% since 2004. These budget constraints limit the…
Conflicting results on prognostic factors for advanced epithelial ovarian cancer (EOC) have been ... more Conflicting results on prognostic factors for advanced epithelial ovarian cancer (EOC) have been reported because of small sample size and heterogeneity of study population. The purpose of this study was to identify factors predictive of poor prognosis in a similarly treated population of women with advanced EOC. A retrospective review of demographic, pathologic, treatment, and outcome data from 1,895 patients with International Federation of Gynecology and Obstetrics stage III EOC who had undergone primary surgery followed by six cycles of intravenous platinum/paclitaxel was conducted. A proportional hazards model was used to assess the association of prognostic factors with progression-free survival (PFS) and overall survival (OS). Increasing age was associated with increased risks for disease progression (HR = 1.06; 95% CI, 1.02 to 1.11 for an increase every 10 years) and death (HR = 1.12; 95% CI, 1.06 to 1.18). Mucinous or clear-cell histology was associated with a worse PFS and OS compared with serous carcinomas. Patients with performance status (PS) 1 or 2 were at an increased risk for recurrence compared with PS 0 (HR = 1.12; 95% CI, 1.01 to 1.24). Compared with patients with microscopic residual disease, patients with 0.1 to 1.0 cm and > 1.0 cm residual disease had an increased risk of recurrence (HR = 1.96; 95% CI, 1.70 to 2.26; and HR = 2.36; 95% CI, 2.04 to 2.73, respectively) and death (HR = 2.11; 95% CI, 1.78 to 2.49; P < .001; and HR = 2.47; 95% CI, 2.09 to 2.92, respectively). Age, PS, tumor histology, and residual tumor volume were independent predictors of prognosis in patients with stage III EOC. These data can be used to identify patients with poor prognosis and to design future tailored randomized clinical trials.
Alkylating agents can be administered in high dosage to patients with ovarian cancer using autolo... more Alkylating agents can be administered in high dosage to patients with ovarian cancer using autologous bone marrow support, but drug-resistant tumor cells can still persist. Immunotoxins provide reagents that might eliminate drug resistant cells. In the present study, concurrent treatment with alkylators and immunotoxins proved superior to treatment with each agent alone. Toxin immunoconjugates prepared from different monoclonal antibodies and recombinant ricin A chain (rRTA) inhibited clonogenic growth of ovarian cancer cell lines in limiting dilution assays. When alkylating agents and toxin conjugates were used in combination, the addition of the immunotoxins to cisplatin, or to cisplatin and thiotepa, produced synergistic cytotoxic activity against the OVCA 432 and OVCAR III cell lines. Studies performed to clarify the mechanism of action showed that cisplatin and thiotepa had no influence on internalization and binding of the 317G5-rRTA immunotoxin. Intracellular uptake of [195m]Pt-cisplatin was not affected by the immunoconjugate and thiotepa. The combination of the 317G5-rRTA and thiotepa, as well as 317G5-rRTA alone, increased [195m]Pt cisplatin-DNA adduct levels. The immunotoxin alone and in combination with the alkylators decreased intracellular glutathione levels and reduced glutathione-S-transferase activity. Repair of DNA damage induced by the combination of alkylators and 317G5-rRTA was significantly reduced when compared to repair after damage with alkylators alone. These findings suggest that immunotoxins affect levels and activity of enzymes required for the prevention and repair of alkylator damage.
An immunotoxin composed of an antibody to the human transferrin receptor (454A12) and ricin A cha... more An immunotoxin composed of an antibody to the human transferrin receptor (454A12) and ricin A chain (RTA) was shown to inhibit the growth of M11:()\ ( VR-3 tumors in a nude mouse model of human ovarian cancer. Inhibition of tumor growth by 454A12-RTA was related to the dose administered. The antitumor activity of the immunotoxin was blocked by coinjection of
The glutathione transferases comprise a family of isoenzymes, one or more of which are involved i... more The glutathione transferases comprise a family of isoenzymes, one or more of which are involved in the conjugation of alkylating agents to glutathione (GSH). Increased GSH transferase activity has been shown to underlie acquired resistance to several alkylating agents. Ethacrynic acid inhibits the isoenzymes of GSH transferase with 50% inhibitory- concentration values ranging from 0.3 to 6.0 MMand has been
The role of glutathione (GSH) in tumor cell resistance to alkylating agents and platinum compound... more The role of glutathione (GSH) in tumor cell resistance to alkylating agents and platinum compounds is suggested by a body of laboratory and clinical studies. The rate-limiting enzyme in GSH synthesis is y-glutamyl- cysteine synthetase (y-GCS), the expression of which is proportional both to GSH content and to the level of resistance in ovarian cancer cell lines. The role of
We have examined 41 forms of ovarian cancer for genetic alterations on chromosome 9 using a combi... more We have examined 41 forms of ovarian cancer for genetic alterations on chromosome 9 using a combination of five RFLP DNA probes and 15 simple tandem repeat polymorphisms. Genetic imbalance (i.e., loss of heterozygosity, microsatellite instability, amplification) for 1 or more informative markers on chromosome 9 was observed in 66% (27 of 41) of our tumor panel. Genetic imbalance was observed on 9q in 59% (24 of 41) of tumors informative for at least one locus. In contrast, only 13% (5 of 40) of informative tumors demonstrated a genetic alteration involving 9p. Furthermore, allelic loss on 9q was more common in late stage tumors (63%, 17 of 27) and poorly differentiated tumors (75%, 15 of 20) as compared to benign and early stage tumors (30%, 3 of 10). Evaluation of 15 tumors showing limited regions of genetic imbalance has identified 2 candidate tumor suppressor regions on 9q and 1 on 9p. Interestingly, the regions defined to 9p21-p24, 9q31, and 9q32-q34 all overlap with several kno...
The optimum integration of chemotherapy and irradiation is of potential clinical significance in ... more The optimum integration of chemotherapy and irradiation is of potential clinical significance in the treatment of ovarian cancer. A series of human ovarian cancer cell lines have been developed in which dose-response relationships to standard anticancer drugs have been determined, and the patterns of cross-resistance between these drugs and irradiation have been established. By stepwise incubation with drugs, sublines of A2780, a drug-sensitive cell line, have been made 100-fold, 10-fold, and 10-fold more resistant to Adriamycin (2780AD), melphalan (2780ME), and cisplatin (2780CP). Two additional cell lines, NIH:OVCAR-3nu(Ag+) and NIH:OVCAR-4(Ag+), were established from drug-refractory patients. 2780ME, 2780CP, OVCAR-3nu(Ag+), and OVCAR-4(Ag+) are all cross-resistant to irradiation, with DOS of 146, 187, 143, and 203, respectively. However, 2780AD remains sensitive to radiation, with a DO of 111, which is similar to that of A2780 (101). Glutathione (GSH) levels are elevated in 2780M...
A human ovarian cancer cell line, A2780, derived from an untreated ovarian cancer patient and rel... more A human ovarian cancer cell line, A2780, derived from an untreated ovarian cancer patient and relatively sensitive to cisplatin was treated by stepwise incubation with cisplatin to produce a cisplatin-resistant variant, 2780CP. The relative abilities of these cell lines to repair cisplatin-induced damage to cellular DNA then was examined by measure of [3H]thymidine incorporation into normal density DNA separated from bromodeoxyuridine-substituted DNA on alkaline cesium chloride gradients. These studies revealed that primary cisplatin resistance present in 2780CP was associated with a near twofold-increased ability to repair damage induced by the drug under conditions where 2780CP was approximately 5-fold resistant to cisplatin. Aphidicolin, a specific inhibitor of DNA polymerase alpha, showed a dose-dependent capacity to inhibit DNA repair in this system with maximum inhibition of 63% at 4 micrograms/ml. It was also found that inhibition of DNA repair during and shortly after cispla...
Single-agent chemotherapy with cisplatin or carboplatin can induce remissions in approximately 30... more Single-agent chemotherapy with cisplatin or carboplatin can induce remissions in approximately 30% of previously treated patients with advanced stage ovarian cancer. Previous studies have shown that the extent of platinum-DNA adduct formation measured in WBC DNA of ovarian cancer patients treated with cisplatin or carboplatin is directly associated with disease response (Reed et al., Proc. Natl. Acad. Sci. USA, 84: 5024-5028, 1987). It has been unclear whether adduct level in WBC DNA is independent of known prognostic variables in this disease, or whether adduct level parallels a known prognostic variable that can be more easily monitored. In a cohort of 24 ovarian cancer patients treated with single-agent cisplatin or carboplatin, we retrospectively assessed the relationship between disease response, platinum-DNA adducts in WBC DNA, and each of eight prognostic variables by both univariate analysis and multivariate analysis. The prognostic variables evaluated included: response to ...
Journal of clinical oncology : official journal of the American Society of Clinical Oncology, 2003
In randomized trials the combination of cisplatin and paclitaxel was superior to cisplatin and cy... more In randomized trials the combination of cisplatin and paclitaxel was superior to cisplatin and cyclophosphamide in advanced-stage epithelial ovarian cancer. Although in nonrandomized trials, carboplatin and paclitaxel was a less toxic and highly active combination regimen, there remained concern regarding its efficacy in patients with small-volume, resected, stage III disease. Thus, we conducted a noninferiority trial of cisplatin and paclitaxel versus carboplatin and paclitaxel in this population. Patients with advanced ovarian cancer and no residual mass greater than 1.0 cm after surgery were randomly assigned to receive cisplatin 75 mg/m2 plus a 24-hour infusion of paclitaxel 135 mg/m2 (arm I), or carboplatin area under the curve 7.5 intravenously plus paclitaxel 175 mg/m2 over 3 hours (arm II). Seven hundred ninety-two eligible patients were enrolled onto the study. Prognostic factors were similar in the two treatment groups. Gastrointestinal, renal, and metabolic toxicity, as w...
We have previously obtained, by exposure to near continuous increas ing concentrations of cisplat... more We have previously obtained, by exposure to near continuous increas ing concentrations of cisplatin, a panel of human ovarian cancer cell lines that exhibit a wide range of primary resistance to the drug (9- to >400- fold). These cells had strikingly increased (4- to 50-fold) levels of gluta- thione (GSH) as compared with the drug-sensitive cells of origin (A. K.
Phosphonacetyl-l-aspartate (PALA), an inhibitor of aspartate transcarbamylase that depletes uridi... more Phosphonacetyl-l-aspartate (PALA), an inhibitor of aspartate transcarbamylase that depletes uridine nucleotide pools, selectively potentiates the antitumor activity of 5-fluorouracil (5-FU) in preclinical models. Due to the promising results we obtained using PALA/5-FU in colorectal cancer, we performed a phase II trial in patients presenting with advanced pancreatic cancer. PALA was given intravenously at 250 mg/m2 on day 1, followed 24
Proceedings of The National Academy of Sciences, 1987
Fifty-five ovarian cancer patients receiving platinum drug-based chemotherapy have been studied p... more Fifty-five ovarian cancer patients receiving platinum drug-based chemotherapy have been studied prospectively to determine the extent of formation of the bidentate intrastrand adducts of diammineplatinum covalently attached to the N7 positions of adenosine and/or guanosine in leukocyte DNA. Data for clinical response, obtained from medical records, were then correlated with the adduct values. Patients were treated with platinum-based single-agent or
A series of cisplatin-resistant cell lines were used to examine the formation and removal of plat... more A series of cisplatin-resistant cell lines were used to examine the formation and removal of platinum-DNA adducts from the overall genome and the formation and removal of cisplatin-interstrand cross-links from specific genomic regions. Cisplatin accumulation and DNA platination levels, which correlated linearly, were similar in three of the resistant cell lines despite differences in their primary cisplatin resistance. Increased platinum removal from total genomic DNA was found to be associated with increased resistance. Interstrand cross-link levels were found to be 2- to 4-fold lower in the 28S ribosomal RNA gene and a non-coding genomic region of the resistant cell lines as compared with the parental A2780 cell line. In addition, 1.2- to 2.7-fold more cross-links were formed in the non-coding region than in the ribosomal RNA gene in all of the cell lines. Interstrand cross-links were removed more rapidly from both regions of the highly cisplatin-resistant C80 and C200 cells and from the ribosomal RNA gene only in the cell lines of lower resistance. The results support a role for DNA repair and alterations in interstrand cross-link formation in cisplatin resistance and provide evidence for heterogeneous interstrand cross-link formation in the genome.
Epithelial ovarian cancer is neither a common nor a rare disease. In the United States, the preva... more Epithelial ovarian cancer is neither a common nor a rare disease. In the United States, the prevalence of ovarian cancer in postmenopausal women (1 in 2,500) significantly affects strategies for prevention and detection. If chemoprevention for ovarian cancer were provided to all women over the age of 50, side effects would have to be minimal in order to achieve an acceptable ratio of benefit to risk. This ratio might be improved by identifying subsets of individuals at increased risk or by bundling prevention of ovarian cancer with treatment for other more prevalent conditions. Approximately 10% of ovarian cancers are familial and relate to mutations of BRCA1, BRCA2, and mismatch repair genes. More subtle genetic factors are being sought in women with apparently sporadic disease. Use of oral contraceptive agents for as long as 5 years decreases the risk of ovarian cancer in later life by 50%. In one study, fenretinide (4-HPR) delayed development of ovarian cancer in women at increased risk of developing breast and ovarian cancer. Accrual to confirmatory studies has been prohibitively slow and prophylactic oophorectomy is recommended for women at increased genetic risk. Vaccines may have a role for prevention of several different cancers. Breast and ovarian cancers express mucins that could serve as targets for vaccines to prevent both cancers. Early detection of ovarian cancer requires a strategy with high sensitivity (> 75% for stage I disease) and very high specificity (> 99.6%) to achieve a positive predictive value of 10%. Transvaginal sonography (TVS) has achieved these values in some studies, but is limited by the cost of annual screening in a general population. Two-stage strategies that incorporate both serum markers and TVS promise to be more cost-effective. An algorithm has been developed that calculates risk of ovarian cancer based on serial CA125 values and refers patients at highest risks for TVS. Use of the algorithm is currently being evaluated in a trial with 200,000 women in the United Kingdom that will critically test the ability of a two-stage screening strategy to improve survival in ovarian cancer. Whatever the outcome, additional serum markers will be required to detect all patients in an initial phase of screening. More than 30 serum markers have been evaluated alone and in combination with CA125. Recent candidates include: HE4, mesothelin, M-CSF, osteopontin, kallikrein(s) and soluble EGF receptor. Proteomic approaches have been used to define a distinctive pattern of peaks on mass spectroscopy or to identify a limited number of critical markers that can be assayed by more conventional methods. Several groups are placing known markers on multiplex platforms to permit simultaneous assay of multiple markers with very small volumes of serum. Mathematical techniques are being developed to analyze combinations of marker levels to improve sensitivity and specificity. In the future, serum markers should improve the sensitivity of detecting recurrent disease as well as facilitate earlier detection of ovarian cancer.
Human ovarian cancer cell lines with stable cisplatin resistance have been developed by chronic e... more Human ovarian cancer cell lines with stable cisplatin resistance have been developed by chronic exposure of the parent cisplatin-sensitive A27X0line to increasing concentrations of cisplatin. 2780eâ"¢ (CP8 refers to this cell line's growth in medium containing 8 MM cisplatin) has several clonal cytogenetic abnormalities but lacks homogeneously staining re gions or double-minute chromosomes. It has a significantly greater mon- olayer
The effectiveness of adriamycin in the treatment of ovarian cancer and other human tumors has bee... more The effectiveness of adriamycin in the treatment of ovarian cancer and other human tumors has been limited by the development of drug resistance. Verapamil, a calcium channel blocking agent, completely reversed adriamycin resistance in human ovarian cancer cells with moderate (three- to sixfold) degrees of resistance and partially reversed resistance in highly (150-fold) resistant cells. The potentiating effect of verapamil was due to inhibition of adriamycin efflux in the resistant cells. These results have led to a clinical trial of adriamycin and verapamil in refractory ovarian cancer patients.
A MESSAGE FROM ASCO&a... more A MESSAGE FROM ASCO'S PRESIDENT: For the third year, the American Society of Clinical Oncology (ASCO) is publishing Clinical Cancer Advances: Major Research Advances in Cancer Treatment, Prevention, and Screening, an annual review of the most significant cancer research presented or published over the past year. ASCO publishes this report to demonstrate the important progress being made on the front lines of clinical cancer research today. The report is intended to give all those with an interest in cancer care-the general public, cancer patients and organizations, policymakers, oncologists, and other medical professionals-an accessible summary of the year's most important cancer research advances. These pages report on the use of magnetic resonance imaging for breast cancer screening, the association between hormone replacement therapy and breast cancer incidence, the link between human papillomavirus and head and neck cancers, and the use of radiation therapy to prevent lung cancer from spreading. They also report on effective new targeted therapies for cancers that have been historically difficult to treat, such as liver cancer and kidney cancer, among many others. A total of 24 advances are featured in this year's report. These advances and many more over the past several years show that the nation's long-term investment in cancer research is paying off. But there are disturbing signs that progress could slow. We are now in the midst of the longest sustained period of flat government funding for cancer research in history. The budgets for the National Institutes of Health and the National Cancer Institute (NCI) have been unchanged for four years. When adjusted for inflation, cancer research funding has actually declined 12% since 2004. These budget constraints limit the…
Conflicting results on prognostic factors for advanced epithelial ovarian cancer (EOC) have been ... more Conflicting results on prognostic factors for advanced epithelial ovarian cancer (EOC) have been reported because of small sample size and heterogeneity of study population. The purpose of this study was to identify factors predictive of poor prognosis in a similarly treated population of women with advanced EOC. A retrospective review of demographic, pathologic, treatment, and outcome data from 1,895 patients with International Federation of Gynecology and Obstetrics stage III EOC who had undergone primary surgery followed by six cycles of intravenous platinum/paclitaxel was conducted. A proportional hazards model was used to assess the association of prognostic factors with progression-free survival (PFS) and overall survival (OS). Increasing age was associated with increased risks for disease progression (HR = 1.06; 95% CI, 1.02 to 1.11 for an increase every 10 years) and death (HR = 1.12; 95% CI, 1.06 to 1.18). Mucinous or clear-cell histology was associated with a worse PFS and OS compared with serous carcinomas. Patients with performance status (PS) 1 or 2 were at an increased risk for recurrence compared with PS 0 (HR = 1.12; 95% CI, 1.01 to 1.24). Compared with patients with microscopic residual disease, patients with 0.1 to 1.0 cm and > 1.0 cm residual disease had an increased risk of recurrence (HR = 1.96; 95% CI, 1.70 to 2.26; and HR = 2.36; 95% CI, 2.04 to 2.73, respectively) and death (HR = 2.11; 95% CI, 1.78 to 2.49; P < .001; and HR = 2.47; 95% CI, 2.09 to 2.92, respectively). Age, PS, tumor histology, and residual tumor volume were independent predictors of prognosis in patients with stage III EOC. These data can be used to identify patients with poor prognosis and to design future tailored randomized clinical trials.
Alkylating agents can be administered in high dosage to patients with ovarian cancer using autolo... more Alkylating agents can be administered in high dosage to patients with ovarian cancer using autologous bone marrow support, but drug-resistant tumor cells can still persist. Immunotoxins provide reagents that might eliminate drug resistant cells. In the present study, concurrent treatment with alkylators and immunotoxins proved superior to treatment with each agent alone. Toxin immunoconjugates prepared from different monoclonal antibodies and recombinant ricin A chain (rRTA) inhibited clonogenic growth of ovarian cancer cell lines in limiting dilution assays. When alkylating agents and toxin conjugates were used in combination, the addition of the immunotoxins to cisplatin, or to cisplatin and thiotepa, produced synergistic cytotoxic activity against the OVCA 432 and OVCAR III cell lines. Studies performed to clarify the mechanism of action showed that cisplatin and thiotepa had no influence on internalization and binding of the 317G5-rRTA immunotoxin. Intracellular uptake of [195m]Pt-cisplatin was not affected by the immunoconjugate and thiotepa. The combination of the 317G5-rRTA and thiotepa, as well as 317G5-rRTA alone, increased [195m]Pt cisplatin-DNA adduct levels. The immunotoxin alone and in combination with the alkylators decreased intracellular glutathione levels and reduced glutathione-S-transferase activity. Repair of DNA damage induced by the combination of alkylators and 317G5-rRTA was significantly reduced when compared to repair after damage with alkylators alone. These findings suggest that immunotoxins affect levels and activity of enzymes required for the prevention and repair of alkylator damage.
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