rottlerin and Adenocarcinoma

We recently found that Rottlerin not only inhibits proliferation but also causes Bcl-2- and Beclin 1-independent autophagic death in apoptosis-resistant breast adenocarcinoma MCF-7 cells. Having excluded a role for canonical signaling pathways, the current study was aimed to investigate the contribution of the AMPK/mTOR axis in autophagy induction and to search for the upstream signaling molecules potentially targeted by Rottlerin. Using several enzyme inhibitors, Western blotting analysis, mTOR siRNA and pull down assay, we demonstrate that the Rottlerin-triggered autophagy is mediated by inhibition of mTORC1 activity through a novel AMPK and mTORC1 phosphorylation-independent mechanism, likely mediated by the direct interaction between Rottlerin and mTOR.

Topics: Acetophenones; Adenocarcinoma; AMP-Activated Protein Kinases; Antineoplastic Agents; Autophagy; Benzopyrans; Breast Neoplasms; Female; Humans; MCF-7 Cells; Mechanistic Target of Rapamycin Complex 1; Multiprotein Complexes; Phosphorylation; Protein Kinase C-delta; Protein Kinase Inhibitors; RNA Interference; Signal Transduction; Time Factors; TOR Serine-Threonine Kinases; Transfection

Prostate cancer is the most commonly diagnosed malignancy in men and shows a predilection for metastasis to the bone. Bradykinin (BK) is an inflammatory mediator, and shows elevated levels in regions of severe injury and inflammatory diseases. The aim of this study was to investigate whether Bradykinin is associated with migration of prostate cancer cells.. Cancer cells migration activity was examined using the Transwell assay. The c-Src and PKCδ phosphorylation was examined by using Western blot method. The qPCR was used to examine the mRNA expression of metalloproteinase. A transient transfection protocol was used to examine NF-κB activity.. We found that bradykinin increased the chemomigration and the expression of MMP-9 of human prostate cancer cells. Bradykinin-mediated chemomigration and metalloproteinase expression was attenuated by PKCδ inhibitor (rottlerin), PKCδ siRNA, c-Src inhibitor (PP2) and c-Src mutant. Activations of PKCδ, c-Src and NF-κB pathways after bradykinin treatment was demonstrated, and bradykinin-induced expression of metalloproteinase and chemomigration activity was inhibited by the specific inhibitor and mutant of PKCδ, c-Src, and NF-κB cascades.. This study showed for the first time that the bradykinin mediates migration of human prostate cancer cells. One of the mechanisms underlying bradykinin directed migration was transcriptional up-regulation of MMP-9 and activation of B2 receptor, PKCδ, c-Src, and NF-κB pathways.

Topics: Acetophenones; Adenocarcinoma; Benzopyrans; Bradykinin; Cell Line, Tumor; Cell Movement; Humans; Male; Matrix Metalloproteinase 9; NF-kappa B; Phosphorylation; Prostatic Neoplasms; Protein Kinase C-delta; Receptor, Bradykinin B2; RNA, Small Interfering; Signal Transduction; src-Family Kinases

Rottlerin is a polyphenolic compound derived from Mallotus philipinensis. In the present study, we show that rottlerin decreased tumor size and stimulated apoptosis in an orthotopic model of pancreatic cancer with no effect on normal tissues in vivo. Rottlerin also induced apoptosis in pancreatic cancer (PaCa) cell lines by interacting with mitochondria and stimulating cytochrome c release. Immunoprecipitation results indicated that rottlerin disrupts complexes of prosurvival Bcl-xL with Bim and Puma. Furthermore, siRNA knockdown showed that Bim and Puma are necessary for rottlerin to stimulate apoptosis. We also showed that rottlerin and Bcl-2 and Bcl-xL inhibitor BH3I-2' stimulate apoptosis through a common mechanism. They both directly interact with mitochondria, causing increased cytochrome c release and mitochondrial depolarization, and both decrease sequestration of BH3-only proteins by Bcl-xL. However, the effects of rottlerin and BH3I-2' on the complex formation between Bcl-xL and BH3-only proteins are different. BH3I-2' disrupts complexes of Bcl-xL with Bad but not with Bim or Puma, whereas rottlerin had no effect on the Bcl-xL interaction with Bad. Also BH3I-2', but not rottlerin, required Bad to stimulate apoptosis. In conclusion, our results demonstrate that rottlerin has a potent proapoptotic and antitumor activity in pancreatic cancer, which is mediated by disrupting the interaction between prosurvival Bcl-2 proteins and proapoptotic BH3-only proteins. Thus rottlerin represents a promising novel agent for pancreatic cancer treatment.

Topics: Acetophenones; Adenocarcinoma; Animals; Antineoplastic Agents; Apoptosis; Apoptosis Regulatory Proteins; Bcl-2-Like Protein 11; bcl-Associated Death Protein; bcl-X Protein; Benzamides; Benzopyrans; Cell Line, Tumor; Cytochromes c; Disease Models, Animal; Enzyme Inhibitors; Humans; Membrane Proteins; Mice; Mice, Nude; Mitochondria; Neoplasm Transplantation; Pancreatic Neoplasms; Protein Kinase C-delta; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-bcl-2; Signal Transduction; Tumor Suppressor Proteins; Xenograft Model Antitumor Assays