Zyflamend induces apoptosis in pancreatic cancer cells via modulation of the JNK pathway.

BACKGROUND: Current pharmacological therapies and treatments targeting pancreatic neuroendocrine tumors (PNETs) have proven ineffective, far too often. Therefore, there is an urgent need for alternative therapeutic approaches. Zyflamend, a combination of anti-inflammatory herbal extracts, that has proven to be effective in various in vitro and in vivo cancer platforms, shows promise. However, its effects on pancreatic cancer, in particular, remain largely unexplored. METHODS: In the current study, we investigated the effects of Zyflamend on the survival of beta-TC-6 pancreatic insulinoma cells (ß-TC6) and conducted a detailed analysis of the underlying molecular mechanisms. RESULTS: Herein, we demonstrate that Zyflamend treatment decreased cell proliferation in a dose-dependent manner, concomitant with increased apoptotic cell death and cell cycle arrest at the G2/M phase. At the molecular level, treatment with Zyflamend led to the induction of ER stress, autophagy, and the activation of c-Jun N-terminal kinase (JNK) pathway. Notably, pharmacological inhibition of JNK abrogated the pro-apoptotic effects of Zyflamend. Furthermore, Zyflamend exacerbated the effects of streptozotocin and adriamycin-induced ER stress, autophagy, and apoptosis. CONCLUSION: The current study identifies Zyflamend as a potential novel adjuvant in the treatment of pancreatic cancer via modulation of the JNK pathway. Video abstract.

Neurotensin, a novel target of Wnt/ß-catenin pathway, promotes growth of neuroendocrine tumor cells.

Wnt/ß-catenin signaling plays a pivotal role in regulating cell growth and differentiation by activation of the ß-catenin/T-cell factor (TCF) complex and subsequent regulation of a set of target genes that have one or more TCF-binding elements (TBEs). Hyperactivation of this pathway has been implicated in numerous malignancies including human neuroendocrine tumors (NETs). Neurotensin (NT), an intestinal hormone, induces proliferation of several gastrointestinal (GI) cancers including cancers of the pancreas and colon. Here, we analyzed the human NT promoter in silico and found at least four consensus TBEs within the proximal promoter region. Using a combination of ChIP and luciferase reporter assays, we identified one TBE (located ∼900 bp proximal from the transcription start site) that was immunoprecipitated efficiently by TCF4-targeting antibody; mutation of this site attenuated the responsiveness to ß-catenin. We also confirmed that the promoter activity and the mRNA and protein expression levels of NT were increased by various Wnt pathway activators and decreased by Wnt inhibitors in NET cell lines BON and QGP-1, which express and secrete NT. Similarly, the intracellular content and secretion of NT were induced by Wnt3a in these cells. Finally, inhibition of NT signaling suppressed cell proliferation and anchorage-independent growth and decreased expression levels of growth-related proteins in NET cells. Our results indicate that NT is a direct target of the Wnt/ß-catenin pathway and may be a mediator for NET cell growth.

Roles of miR-196a on gene regulation of neuroendocrine tumor cells.

This study aims at investigating miR-196a roles using in vitro models. miR-196a was detected in small intestinal neuroendocrine tumors (SI-NETs) and lung NETs. miR-196a target prediction analysis suggested HOXA9, HOXB7, LRP4 and RSPO2 genes for further investigation. The level of these four genes is detectable in SI-NET tissue specimens at different disease stages and serum samples of untreated and somatostatin analogs treated patients with liver metastases. A miR-196a inhibitor was used to silence its effects in NET cells. We show that the four target genes were significantly upregulated at transcriptional level in silenced NET cells. HOXA9, HOXB7, LRP4 and RSPO2 encoded proteins are also upregulated at translational level in miR-196a silenced NET cells. miR-196a downstream genes BMP4, ETS1, CTNNB1, FZD5, LRP5 and LRP6 were significantly upregulated at transcriptional level in miR-196a silenced CNDT2.5 and NCI-H727 cells. In addition, miR-196a clearly does not play a role in NET cell growth control.