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.

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.

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.