Paradigm Shifting of Systemic Chemotherapy for Unresectable Pancreatic Cancer in Japan

Upregulated GDF-15 expression facilitates pancreatic ductal adenocarcinoma progression through orphan receptor GFRAL

Growth and differentiation factor 15 (GDF-15) has been studied as an important hallmark of cancer. However, the receptor of GDF-15 in pancreatic cancer cell remains unclear. Here, we investigated its biological effects in pancreatic ductal adenocarcinoma (PDAC). We found that aberrant GDF-15 expression positively correlated with poor survival of PDAC patients. GDF-15 protein enhanced tumor cell proliferation in two pancreatic cancer lines, AsPC-1 and BxPC-3. Knockdown GDF-15 attenuated its biological function in vitro and reduced PDAC cell tumorigenesis upon xenotransplantation into nude mice. Moreover, we identified that glial-derived neurotropic factor family receptor α-like (GFRAL) was upregulated in PDAC tissues and positively correlated with GDF-15 expression. High GFRAL expression was significantly associated with poor survival in PDAC patients. Furthermore, we identified that the biological effects of GDF-15 are mediated by its receptor GFRAL which is present in PDAC cells. After overexpression GFRAL in pancreatic cancer cells, the effect of GDF-15 was significantly enhanced. Overall, our findings demonstrated that the GDF-15 secreted by PDAC cells, binds to GFRAL, itself localized in PDAC cells, to promote cancer cell growth and metastasis through the GDF-15/GFRAL signaling pathway.

ERas regulates cell proliferation and epithelial-mesenchymal transition by affecting Erk/Akt signaling pathway in pancreatic cancer

Pancreatic cancer is the fourth most common lethal malignancy with an overall 5-year survival rate of less than 5%. ERas, a novel Ras family member, was first identified in murine embryonic stem cells and is upregulated in various cancers. However, the expression and potential role of ERas in pancreatic cancer have not been investigated. In this study, we found that ERas mRNA and protein were upregulated in pancreatic cancer tissues and cells compared with controls. Knockdown of ERas in pancreatic cancer cells by siRNA significantly decreased cell proliferation, colony formation, migration, and invasion and promoted cell apoptosis in vitro. Epithelial-mesenchymal transition (EMT) is closely related to tumor progression. We observed a significant decrease in N-cadherin expression in pancreatic cancer cells in response to ERas gene silencing by immunofluorescence assay and western blot. Furthermore, tumor growth and EMT were inhibited in xenografts derived from pancreatic cancer cells with ERas downregulation. We further investigated the regulatory mechanisms of ERas in pancreatic cancer and found that ERas may activate the Erk/Akt signaling pathway. Moreover, Erk inhibitor decreased pancreatic cancer cells proliferation and colony formation activities. Our data suggest that targeting ERas and its relevant signaling pathways might represent a novel therapeutic approach for the treatment of pancreatic cancer.

Randomized, Multicenter, Phase II Trial of Gemcitabine and Cisplatin With or Without Veliparib in Patients With Pancreas Adenocarcinoma and a Germline BRCA/PALB2 Mutation

PURPOSE

Five percent to 9% of pancreatic ductal adenocarcinomas (PDACs) develop in patients with a germline BRCA1/2 or PALB2 (gBRCA/PALB2+) mutation. Phase IB data from a trial that used cisplatin, gemcitabine, and veliparib treatment demonstrated a high response rate (RR), disease control rate (DCR), and overall survival (OS) in this population. We designed an open-label, randomized, multicenter, two-arm phase II trial to investigate cisplatin and gemcitabine with or without veliparib in gBRCA/PALB2+ PDAC.

PATIENTS AND METHODS

Eligible patients had untreated gBRCA/PALB2+ PDAC with measurable stage III to IV disease and Eastern Cooperative Oncology Group performance status of 0 to 1. Treatment for patients in arm A consisted of cisplatin 25 mg/m2 and gemcitabine 600 mg/m2 intravenously on days 3 and 10; treatment for patients in arm B was the same as that for patients in arm A, and arm A also received veliparib 80 mg orally twice per day on days 1 to 12 cycled every 3 weeks. The primary end point was RRs of arm A and arm B evaluated separately using a Simon two-stage design. Secondary end points were progression-free survival, DCR, OS, safety, and correlative analyses.

RESULTS

Fifty patients were evaluated by modified intention-to-treat analysis. The RR for arm A was 74.1% and 65.2% for arm B (P = .55); both arms exceeded the prespecified activity threshold. DCR was 100% for arm A and 78.3% for arm B (P = .02). Median progression-free survival was 10.1 months for arm A (95% CI, 6.7 to 11.5 months) and 9.7 months for arm B (95% CI, 4.2 to 13.6 months; P = .73). Median OS for arm A was 15.5 months (95% CI, 12.2 to 24.3 months) and 16.4 months for arm B (95% CI, 11.7 to 23.4 months; P = .6). Two-year OS rate for the entire cohort was 30.6% (95% CI, 17.8% to 44.4%), and 3-year OS rate was 17.8% (95% CI, 8.1% to 30.7%). Grade 3 to 4 hematologic toxicities for arm A versus arm B were 13 (48%) versus seven (30%) for neutropenia, 15 (55%) versus two (9%) for thrombocytopenia, and 14 (52%) versus eight (35%) for anemia.

CONCLUSION

Cisplatin and gemcitabine is an effective regimen in advanced gBRCA/PALB2+ PDAC. Concurrent veliparib did not improve RR. These data establish cisplatin and gemcitabine as a standard approach in gBRCA/PALB2+ PDAC.