miR-19a promotes the metastasis and EMT through CUL5 in prostate cancer cell line PC3.

PURPOSE: Prostate cancer is an epithelial malignancy that occurs in the prostate and metastasis is a challenge of the treatment of prostate cancer. MicroRNA (miR)-19a was usually upregulated in several cancers at the roles of miR-19a in the metastasis in prostate cancer are still unclear. METHODS: A normal prostate epithelial cell line P69 and two prostate cancer cell lines PC3 and DU145 were used in this study. The mRNA levels of miR-19a and CUL5 were measured using qRT-PCR assay. Transwell and Western blot assays were conducted to calculate cell metastasis and epithelial-mesenchymal transition (EMT) properties in PC3 cells. Luciferase reporter assay was applied to validate that miR-19a targeted to CUL5. RESULTS: The expression of miR-19a was high in prostate cancer and its overexpression predicted poor outcome of prostate cancer patients. miR-19a regulated the expression of CUL5 by directly targeting its mRNA 3'-UTR in PC3 cells. The expression of CUL5 was lower in prostate cancer tissues and cell lines than in non-tumor tissues and normal cells. Downregulation of CUL5 predicted worse outcome of prostate cancer patients. miR-19a promoted cell migration, invasion and EMT in prostate cancer by directly binding to CUL5 mRNA 3'-UTR. CUL5 partially reversed the roles of miR-19a on the metastasis in prostate cancer. CONCLUSION: miR-19a promoted migratory, invasive and EMT abilities by binding to CUL5 in prostate cancer. The newly identified miR-19a/CUL5 axis provides novel insight into the pathogenesis of prostate cancer.

Polysaccharides from Polygonatum Inhibit the Proliferation of Prostate Cancer-Associated Fibroblasts.

Inhibition of cancer-associated broblasts (CAFs) may improve the efficacy of cancer therapy. Polysaccharide extracted from polygonatum can selectively inhibit the growth of prostate-CAFs (<.001) without inhibiting the growth of normal broblasts (NAFs). Polysaccharides from polygonatum stimulate autophagy of prostate-CAFs. 3-methyl-adenine(3-MA) is an autophagy inhibitor. 3-MA was added to prostate-CAFs with polysaccharide from polygonatum to determine whether autophagy plays an important role in the restrained effect. Finally, polysaccharide from polygonatum treatment significantly increased the activation of Beclin-1 and LC3, key autophagy proteins. Polysaccharides from polygonatum stimulate autophagy of prostate-CAFs and inhibits prostate-CAF growth, indicating that a novel anti-cancer strategy involves inhibiting the growth of prostate- CAFs.

IKKß/NFκBp65 activated by interleukin-13 targets the autophagy-related genes LC3B and beclin 1 in fibroblasts co-cultured with breast cancer cells.

Interleukin-13 (IL-13), a Th2 cytokine, plays an important role in fibrosis, inflammation, tissue hyperresponsiveness and tumor development. Although studies have demonstrated that IL-13 exerts its roles through signal transducer and activator of transcription 6 (STAT6) signaling pathway, recent studies have revealed that I kappa B kinase (IKK)/nuclear factor kappa B (NFκB) pathway may also be involved in. The aim of this study was to investigate whether IL-13 delivers signals to IKKß/NFκBp65 and whether autophagy genes are IL-13-induced the activation of NFκBp65 transcriptional targets in fibroblasts of breast tumor stroma. We examined the phosphorylation of IKKß, the activation of NFκBp65 and NFκBp65-targeted autophagy genes in fibroblasts co-cultured with breast cancer cells under the condition of IL-13 stimulation. Results of this study showed that IL-13 induced IKKß phosphorylation in the fibroblast line ESF co-cultured with breast cancer cell line BT474, and subsequently NFκBp65 was activated and aimed at beclin 1 and microtubule-associated protein 1 light chain 3 B (MAP1LC3B or LC3B) in these ESF cells. BMS345541, an inhibitor of IKK/NFκB pathway, significantly inhibited the IL-13-induced the activation of NFκB and also inhibited NFκB-targeted beclin 1 and LC3B expression. Our results suggest that IL-13 regulates beclin 1 and LC3B expression through IKKß/NFκBp65 in fibroblasts co-cultured with breast cancer cells, and IL-13 plays role in activating IKKß/NFκBp65.

Downregulation of caveolin­1 upregulates the expression of growth factors and regulators in co­culture of fibroblasts with cancer cells.

Reduced expression levels of caveolin­1 (Cav­1) in tumor stromal fibroblasts influences the occurrence and progression of tumors, particularly in breast cancer, but the relevant molecular mechanism is unclear. The present study aimed to clarify the potential mechanism underlying the promotion of tumor growth by reduced Cav­1 expression levels, by investigating Cav­1­targeted molecules in fibroblasts and breast cancer cells. The expression of growth factors in the ESF fibroblast cell line transfected with Cav­1 small interfering RNA (siRNA) was examined. The expression of apoptotic regulators in the BT474 breast cancer cell line that was co­cultured with the fibroblasts, was also investigated. The transfection of Cav­1­targeting siRNA in ESF cells resulted in efficient and specific inhibition of Cav­1 expression. The downregulation of Cav­1 increased the expression and secretion of stromal cell­derived factor­1 (SDF­1), epidermal growth factor (EGF) and fibroblast­specific protein­1 (FSP­1) in ESF cells. This resulted in the accelerated proliferation of the breast cancer cells. Tumor protein 53­induced glycolysis and apoptosis regulator (TIGAR) was upregulated in the BT474 cells under the condition of co­culture with Cav­1 siRNA fibroblasts, while levels of reactive oxygen species (ROS) were decreased, resulting in apoptosis inhibition in the breast cancer cells. These results demonstrated that the downregulation of Cav­1 promoted the growth of breast cancer cells through increasing SDF­1, EGF and FSP­1 in tumor stromal fibroblasts, and TIGAR levels in breast cancer cells. To the best of our knowledge, the present study supports the hypothesis that Cav­1 possesses tumor­suppressor properties, with the mechanism of Cav­1­dependent signaling involving the regulation of SDF­1, EGF, FSP­1 and TIGAR.