Pancreatic cancer has a poor prognosis with its five-year survival rate lower than that of any other cancer type because it is difficult to detect in the early stages. Gemcitabine, a standard treatment for pancreatic cancer, often has poor outcomes for patients as a result of chemoresistance. Therefore, novel therapeutic targets must be identified to overcome gemcitabine-resistance. Here, we found that SLC38A5, a glutamine transporter, is more highly overexpressed in gemcitabine-resistant patients than in gemcitabine-sensitive patients. Furthermore, the deletion of SLC38A5 decreased the proliferation and migration of gemcitabine-resistant PDAC cells. We also found that the inhibition of SLC38A5 triggered the ferroptosis signaling pathway via RNA sequencing. Also, silencing SLC38A5 induced mitochondrial dysfunction and reduced glutamine uptake and glutathione (GSH) levels, and downregulated the expressions of GSH-related genes NRF2 and GPX4. The blockade of glutamine uptake negatively modulated the mTOR-SREBP1-SCD1 signaling pathway. Therefore, suppression of SLC38A5 triggers ferroptosis via two pathways that regulate lipid ROS levels. Similarly, we observed knockdown of SLC38A5 restored gemcitabine sensitivity by hindering tumor growth and metastasis in the orthotopic mouse model. Altogether, our results demonstrated that SLC38A5 could be a novel therapeutic target to overcome gemcitabine-resistance in PDAC therapy.

Pancreatic ductal adenocarcinoma (PDAC) is expected to be the second cause of cancer death by 2022. For nearly 80% of patients, diagnosis occurs at an advanced, non-surgical stage, making such patients incurable. Gemcitabine is still an important component in PDAC treatment and is most often used as a backbone to test new targeted therapies and there is, to date, no routine biomarker to predict its efficacy. Samples from a phase III randomized trial were used to develop trough a large approach based on blood-based liquid biopsy, transcriptome profiling, and machine learning, a 9 gene predictive signature for gemcitabine sensitivity. Patients with a positive test (41.6%) had a significantly longer progression free survival (PFS) (3.8 months vs. 1.9 months p=0.03) and a longer overall survival (OS) (14.5 months vs. 5.1 p<0.0001). In multivariate analyses, this signature was independently associated with PFS (HR=0.5 (0.28-0.9) p=0.025) and OS (HR=0.39 (0.21-0.7) p=0.002).

Pancreatic cancer is an intractable disease with the worst prognosis of all cancers. The currently used treatment regimens do not significantly impact patient survival, and therefore, effective treatment strategies are urgently needed. Drug repurposing, which identifies new indications for existing and approved drugs, has proven to be a promising approach to anti-cancer drug discovery. Indeed the antihelmintic drug, pyrvinium pamoate has shown promise as an anti-pancreatic cancer drug, but to date, the inhibition of mitochondrial function is the only mechanism of action described in pancreatic cancer. This study showed, using pancreatic cancer 2D cell cultures and 3D spheroids, that pyrvinium pamoate exhibited short- and long-term cytotoxicity, inhibited epithelial-to-mesenchymal transition and cell invasion and migration. Mechanistically, pyrvinium pamoate induced DNA damage, inhibited the PI3K/AKT cell survival pathway, and triggered cell cycle arrests, as well as apoptotic and autophagic cell death. Importantly, pyrvinium pamoate acted synergistically with the first-line drug, gemcitabine in 2D and 3D pancreatic cancer cell culture models. This study provided evidence that pyrvinium pamoate is effective as a single agent and in combination with gemcitabine for the treatment of pancreatic cancer.

Cancer associated cachexia (CAC) is a critical contributor to pancreatic ductal adenocarcinoma (PDAC) mortality. Thus, there is an urgent need for new strategies to mitigate PDAC-associated cachexia; and the exploration of dietary interventions is a critical component. We previously observed that a ketogenic diet (KD) combined with gemcitabine enhances overall survival in the autochthonous LSL-KrasG12D/+; LSL-Trp53 R172H/+; Pdx1-Cre (KPC) mouse model. In this study, we investigated the effect and cellular mechanisms of a KD in combination with gemcitabine on the maintenance of skeletal muscle mass in KPC mice. For this purpose, male and female pancreatic tumor-bearing KPC mice were allocated to a control diet (CD), a KD, a CD + gemcitabine (CG), or a KD + gemcitabine (KG) group. We observed that a KD or a KG mitigated muscle strength decline over time and presented higher gastrocnemius weights compared CD-fed mice. Mechanistically, we observed sex-dependent effects of KG treatment, including the inhibition of autophagy, and increased phosphorylation levels of eIF2α in KG-treated KPC mice when compared to CG-treated mice. Our data suggests that a KG results in preservation of skeletal muscle mass. Additional research is warranted to explore whether this diet-treatment combination can be clinically effective in combating CAC in PDAC patients.

Cancer and infectious diseases are two of the world's major public health problems. Gemcitabine (GEM) is an effective chemotherapeutic agent against several types of cancer. In this study, we developed macrocapsules by incorporating GEM into a chitosan matrix blended with magnetite and zeolite. The physico-chemical characterization of the precursor materials and the new delivery system was carried out by HRTEM-ED, XRD, FESEM-EDS, FT-IR, TGA, encapsulation efficiency (%E.E.) and release profiles at pH 7.4 and 5.0. Cell viability tests on A549 and H1299 cell lines and microbiological properties against staphylococcal strains were performed. Our results revealed the successful production of hemispherical capsules with an average diameter of 1.22 mm, a rough surface and characteristic FT-IR material interaction bands. GEM encapsulation rates exceeded 80%, and release profiles were well-controlled over 24 hours at tested pH levels. Notably, cell viability in H1299 cells was lower than the free GEM control. Moreover, the formulation exhibited potent antimicrobial activity against Staphylococcus epidermidis, highlighting its dual action as a chemotherapeutic and antimicrobial agent. This dual effect underscores the potential of these macrocapsules as innovative delivery system for treating lung cancer in patients who are also at risk of infectious diseases and who are immunosuppressed.

Gemcitabine (2',2'-difluoro-2'-deoxycytidine), a widely used anticancer drug, is considered as a gold standard in treating aggressive pancreatic cancers. Gamma-proteobacteria that colonize the pancreatic tumors contribute to chemoresistance against gemcitabine by metabolizing the drug to a less active, deaminated, form. The gemcitabine transporters of these bacteria are unknown to date. Furthermore, there is no complete knowledge on the gemcitabine transporters in Escherichia coli or any other related proteobacteria. In this study, we investigate the complement of gemcitabine transporters in E. coli K-12 and two common chemoresistance-related bacteria (Klebsiella pneumoniae, Citrobacter freundii). We find that E. coli K-12 has two high-affinity gemcitabine transporters with distinct specificity properties, namely NupC and NupG, whereas the gemcitabine transporters of C. freundii and K. pneumoniae include the NupC and NupG orthologs, indistinguishable functionally from their counterparts, and, in K. pneumoniae, one additional NupC variant, designated KpNupC2. All these bacterial transporters have higher affinity for gemcitabine than their human counterparts. The highest affinity (KM 2.5-3.0 μΜ) is exhibited by NupGs of the Bacteria-specific Nucleoside-H+ Symporter (NHS) family followed by NupCs (KM 10-13 μΜ) of the Concentrative Nucleoside Transporter (CNT) family, 15-100 times higher than the affinities reported for the human gemcitabine transporter hENT1/SLC29A1 which is primarily associated with gemcitabine uptake in the pancreatic adenocarcinoma cells. Our results offer a basis for further insight into the role of specific bacteria in drug availability within tumors and understanding the structure-function differences of bacterial and human drug transporters.

Bacillus Calmette-Guérin (BCG) therapy for patients with non-muscle invasive bladder cancer (NMIBC) faces limitations in efficacy and significant side effects, aggravated by a recent global shortage. In this prospective clinical study, we report outcomes of sequential intravesical adminis-tration of gemcitabine and docetaxel (Gem/Doce) as the first-line treatment in BCG-naïve patients with high-risk NMIBC (HR NMIBC). From October 2019 until April 2022, we enrolled 52 patients and followed treatment protocol set by the University of Iowa. Follow-up assessments were con-ducted every 3 months. In this cohort, 25 (48.1%) patients were diagnosed with T1HG bladder cancer, 10 (19.2%) patients had carcinoma in situ (CIS), and 17 (32.7%) patients had a combination of CIS+T1HG. Median time to first recurrence in T1HG, CIS and T1HG+CIS groups was 11, 10.5 and 8.8 months, respectively. The recurrence-free survival was 98.1%, 94.2% and 80.8% at 6, 9 and 12 months, respectively. The rate of progression-free survival was 100%, 98.1% and 92.3% at 6, 9 and 12 months, respectively. We demonstrated the safety and efficacy of Gem/Doce therapy in BCG-naïve patients with HR NMIBC during a one-year follow-up. Further research with extended follow-up, as well as direct comparison of Gem/Doce and other anticancer agents, are essential.

Pancreatic ductal adenocarcinoma (PDA) remains the most lethal malignancy due to lack of an effective treatment. P21-activated kinases (PAKs) play key roles in PDA growth, and the PAK inhibitor PF-3758309 synergistically reduced PDA growth with gemcitabine. The aim of this study was to determine the effect of PF-3758309 with multiple chemotherapeutic reagents on a panel of patient-derived PDA cell lines. Cells were treated with PF-3758309 plus or minus gemcitabine, 5-fluorouracil (5-FU) or abraxane, and cell proliferation was determined. Protein expression profiles were measured by Western blot. PDA cells were subcutaneously injected into the flanks of SCID mice which were then treated with PF-3758309, gemcitabine, PF-3758309 plus gemcitabine, or gemcitabine plus abraxane. Tumour growth was measured by volume and weight. PF-3758309 enhanced the inhibitory effects of 5-FU, gemcitabine and abraxane on a panel of patient-derived PDA cells, inhibited HIF-1 protein expression and reduced the protein levels of palladin and -SMA in these cells. The combination of PF-3758309 with gemcitabine maximally inhibited PDA growth in vivo, which was comparable to the combination of gemcitabine with abraxane. PF-3758309 enhanced the suppressive effects of multiple chemotherapeutic reagents on the growth of a panel of patient-derived PDA cell lines. The combination of PF-3758309 with gemcitabine provides a potential treatment option with less toxicity than gemcitabine plus abraxane.

Arsenic trioxide (ATO) has been shown to inhibit pancreatic cell growth in vitro and to promote the inhibitory effects of gemcitabine on pancreatic cancer in vivo. However, the high toxicity of ATO associated with the required high doses and indiscriminate targeting has limited its clinical application. This study aimed to determine whether coupling arsenic to a tumor homing peptide would increase the inhibitory potency against pancreatic cancer cells. The effects of this peptide-linked arsenic compound and ATO on pancreatic cancer growth were tested in vitro and in a mouse model. The data demonstrated that the peptide-linked arsenic compound inhibited pancreatic cancer cell growth more potently with IC50 values 10 times lower than ATO. Like ATO, the peptide-linked compound induced cell death and cell cycle arrest. More importantly, the peptide-linked arsenic compound inhibited pancreatic cancer growth in mice and enhanced the inhibitory effect of gemcitabine on pancreatic cancer growth at 2 times lower molar concentration than ATO. These results indicate that the peptide-linked arsenic compound inhibited pancreatic cancer more potently than ATO and suggest a potential clinical use for the combination of gemcitabine with the peptide-linked arsenic compound for the treatment of pancreatic cancer.

The microbiome is capable of modulating the bioavailability of chemotherapy drugs mainly due to metabolizing these agents. Multiple cytostatic bacterial metabolites were recently identified that have cytostatic properties on cancer cells. In this study we addressed the question whether the cytostatic bacterial metabolites (cadaverine, indolepropionic acid, indoxylsulfate) can interfere with the cytostatic effects of the chemotherapy agents used in the management of breast cancer (doxorubicin, gemcitabine, irinotecan, methotrexate, rucaparib, 5-fluorouracil, paclitaxel). The chemotherapy drugs were applied in a wide concentration range to which a bacterial metabolite was added in a concentration within its serum reference range and the effects on cell proliferation were assessed. There was no interference between doxorubicin, gemcitabine, irinotecan, methotrexate, rucaparib and the bacterial metabolites. Nevertheless, cadaverine increased the Hill coefficient of the inhibitory curve of 5-fluorouracil and indolepropionic acid increased the IC50 value of 5-fluorouracil that are either disadvantageous effects or effects of unknown significance. Nevertheless, indolepropionic acid decreased the IC50 value of paclitaxel that is a potentially advantageous combination.

Small-cell lung cancer (SCLC) is a cancer with poor prognosis. For relapsed extensive-stage (ES) SCLC, second-line treatment options are scarce. Topotecan was the only approved treatment in this setting until 2020. Since topotecan induces significant toxicities, alternative off-label regimens are being used. This study evaluated real-world efficacy and safety of Paclitaxel Gemcitabine chemotherapy in patients with relapsed ES-SCLC. We retrospectively reviewed data from all consecutive patients with relapsed ES-SCLC who received Paclitaxel Gemcitabine chemotherapy from september 2008 to january 2022 in two centers. Patient characteristics (n=188) were: PS≥2: 24.5%; brain metastasis: 42%; platinum-sensitive disease: 41%. Patients received Paclitaxel Gemcitabine as second- (77%) third (18%) or fourth (6%) line of therapy. Median progression-free and overall survival were 2.1 (95CI 1.8–2.4) and 3.8 (95CI 3.3–4.8) months in the overall population, respectively, with 17% response rate (RR) and 28% disease-control rate. PS, history of brain radiation, platinum-sensitive disease, liver, and adrenal gland metastasis were associated with longer survival in univariate analysis. PS was the only prognostic factor in multivariate analysis, with 21% RR and 4.1 months median DOR in PS 0-1 patients. Paclitaxel Gemcitabine chemotherapy may represent a treatment option in PS0-1 relapsed SCLC.

Chemotherapy treatment against pancreatic ductal adenocarcinoma (PDAC) is thwarted by tumoral activation of multiple therapy-resistance pathways. The growth hormone (GH) – GH receptor (GHR) pair is a covert driver of multimodal therapy resistance in cancer, and is overexpressed in PDAC tumors, yet the therapeutic potential of targeting the same has not been explored. Here, we report that GHR expression is a negative prognostic factor in patients with PDAC. Combinations of gemcitabine with different GHR antagonists (GHRAs) markedly improve therapeutic outcomes in nude mice xenografts. Employing cultured cells, mouse xenografts, and analyses of the human PDAC transcriptome, we identified that attenuation of the multidrug transporter and epithelial-to-mesenchymal transition programs in the tumors underlie the observed augmentation of chemotherapy efficacy by GHRAs. Moreover, in human PDAC patients, GHR expression strongly correlates with a gene signature of tumor-promotion and immune-evasion, which corroborate with that in syngeneic tumors in wild-type vs. GH transgenic mice. Overall, we found that GH action in PDAC promoted a therapy-refractory gene signature in vivo, which can be effectively attenuated by GHR antagonism. Our results collectively present a proof of concept towards considering GHR antagonist to improve chemotherapeutic outcome in the highly chemoresistant PDAC.