Functional studies show that both STAT3 mutants (R583A and N538A) and STAT3 dominant negative significantly reduce PA-enhanced STAT3 phosphorylation, PA-increased PCa cell proliferation, migration, and invasion.
To develop a potent strategy to increase therapeutic efficacy and reduce drug resistance in prostate cancer therapy, we combined two anti-cancer agents: T40214 (a p-Stat3 inhibitor) and JG244 (a HIF-1α inhibitor) together to treat nude mice bearing human prostate tumor (DU145) and immunocompetent mice (C57BL/6) bearing murine prostate tumor (TRAMP-C2).
In addition, suppression of ZIC5 or PDGFD expression decreased levels of phosphorylated focal adhesion kinase (FAK) and signal transducer and activator of transcription 3 (STAT3) which are associated with PCa and CRC aggressiveness.
Our results indicate that the most primitive cells in prostate cancer require pSTAT3 for survival, rationalizing STAT3 as a therapeutic target to treat advanced prostate cancer.
Previously, we reported that single-stranded oligonucleotides containing consensus STAT3 binding sequences (13410 and 13411) were more effective for inducing apoptosis in prostate cancer cells than antisense STAT3 oligonucleotides.
The identification of the alternative reading frame protein (ARF) / murine double minute protein (MDM2) / p53 tumour suppressor pathway potentially involving the IL-6/STAT3 axis as a restricting factor in prostate cancer deficient in the tumour suppressor phosphatase and tensin homologue (PTEN) opened new avenues to currently available therapies.
In this study, we demonstrate that interleukin 6 induces both WASF3 expression and phosphoactivation in breast and prostate cancer cell lines through the JAK2/STAT3 pathway in two different ways.
These dual functions of ASC-J9<sup>®</sup> to suppress PCa proliferation and invasion (via altering STAT3 sumoylation) may help us to develop a better anti-AR compound that may overcome the current antiandrogens' unwanted side-effect of increasing the metastasis to better suppress the castration-resistant PCa progression.
Since differentiation and growth arrest are often associated processes, we investigated whether STAT3 also mediated NE differentiation in this prostate cancer cell line.
Hence, in the present study, we evaluated the potential of cardamonin (CD), a 2',4'-dihydroxy-6'-methoxychalcone, to modulate STAT3 activation in prostate cancer (PC) cells and found that this chalcone can indeed exhibit significant anticancer effects through negatively regulating STAT3 activation by diverse molecular mechanism(s).
Interleukin-6/signal transducer and activator of transcription 3 promotes prostate cancer resistance to androgen deprivation therapy via regulating pituitary tumor transforming gene 1 expression.
Compound CG-06 had the strongest cytotoxic profile of this series, showing potent effects in human prostate cancer DU-145 cells, in which signal transducer and activator of transcription 3 (STAT3) is constitutively active.
Moreover, in malignant cells harboring constitutively-active Stat3, including human prostate cancer DU145 cells and v-Src-transformed mouse fibroblasts (NIH3T3/v-Src), resveratrol treatment represses Stat3-regulated cyclin D1 as well as Bcl-xL and Mcl-1 genes, suggesting that the antitumor cell activity of resveratrol is in part due to the blockade of Stat3-mediated dysregulation of growth and survival pathways.
Simultaneously targeting PCa AR with siRNA and the CCL2/CCR2-STAT3 axis resulted in better suppression of PCa growth and metastasis in a xenograft PCa mouse model.