STAT3 phosphorylation is required for the HepaCAM-mediated inhibition of castration-resistant prostate cancer cell viability and metastasis

Solamargine induces apoptosis of human renal carcinoma cells via downregulating phosphorylated STAT3 expression

Solamargine (SM), an active compound derived from Solanum nigrum, triggers apoptosis and inhibits the metastatic and oxidative activities of various types of tumor cells. However, the effect of SM on human renal carcinoma cells remains unknown. In the present study, the molecular mechanisms underlying the antitumor effects of SM on ACHN and 786-O cells were elucidated. Specifically, MTT and colony formation assays were conducted to evaluate the impact of SM treatment on the proliferation of ACHN and 786-O cells, and flow cytometry was conducted to determine the influence of SM on the apoptosis rates of these cells. In addition, the expression of target proteins was determined by western blotting. The results revealed that SM not only inhibited cell viability but also promoted the apoptosis of ACHN and 786-O cells in a time- and dose-dependent manner. Moreover, treatment of ACHN and 786-O cells with SM significantly enhanced the caspase-3, caspase-8 and caspase-9 activities. Furthermore, SM downregulated the expression of phosphorylated signal transducer and activator of transcription-3 (p-STAT3) and Bcl-2 but increased the expression of cleaved caspase-3, -8, -9 and Bax. BAY2353, a p-STAT3 inhibitor, inhibited the viability of ACHN and 786-O cells, increased the expression of cleaved caspase-9 and Bax and decreased the expression of p-STAT3 and Bcl-2. Further experiments demonstrated that SM inhibited tumor growth in xenograft nude mice without causing specific toxicity to the major organs. Collectively, these findings indicated that SM not only inhibited the viability but also promoted the apoptosis of ACHN and 786-O cells, through a mechanism involving downregulation of p-STAT3 expression.

STAT3 signaling in prostate cancer progression and therapy resistance: An oncogenic pathway with diverse functions

The categorization of cancers demonstrates that prostate cancer is the most common malignancy in men and it causes high death annually. Prostate cancer patients are diagnosed mainly via biomarkers such as PSA test and patients show poor prognosis. Prostate cancer cells rapidly diffuse into different parts of body and their metastasis is also a reason for death. Current therapies for prostate cancer patients include chemotherapy, surgery and radiotherapy as well as targeted therapy. The progression of prostate cancer cells is regulated by different factors that STAT3 signaling is among them. Growth factors and cytokines such as IL-6 can induce STAT3 signaling and it shows carcinogenic impact. Activation of STAT3 signaling occurs in prostate cancer and it promotes malignant behavior of tumor cells. Induction of STAT3 signaling increases glycolysis and proliferation of prostate cancer cells and prevents apoptosis. Furthermore, STAT3 signaling induces EMT mechanism in increasing cancer metastasis. Activation of STAT3 signaling stimulates drug resistance and the limitation of current works is lack of experiment related to role of STAT3 signaling in radio-resistance in prostate tumor. Calcitriol, capsazepine and β-elemonic are among the compounds capable of targeting STAT3 signaling and its inhibition in prostate cancer therapy. In addition to natural products, small molecules targeting STAT3 signaling have been developed in prostate cancer therapy.

The Protective Effect of miRNA-146a Liposome Nanoparticles on Vascular Smooth Muscle Cells After Coronary Intervention

The abnormal expression of miRNA-146a is related to the progression of coronary arteries. This study intends to explore the protective effect of miRNA-146a on vascular smooth muscle cells (VSMCs) after coronary intervention and the related mechanism. 10 miniature pigs were randomly assigned into control group, model group, blank group, miRNA-146a group, cilostazol group, and STAT3 signaling agonist group followed by analysis of the morphology and viability of VSMCs, expression of miRNA-146a, STAT3, NF-kB, TNF-a, IL-6, and AT-1R as well as the relationship between miR-146a and STAT3. The BNP (192.39±12.32) pg/ml and cTnI (14.20±2.12) μg/L of model group were significantly higher than those of control group (P < 0.05). miRNA-146a level was highest in miRNA-146a group and cilostazol group, while lower in other two groups with the lowest level in agonist group (P <0.05). The cell viability and AngII level of miRNA-146a group and cilostazol group were lower, and higher in the other two groups with highest level in pathway agonist group (P < 0.05). miRNA-146a group and cilostazol group showed lower expressions of STAT3, NF-kB, TNF-a, IL-6, AT-1R than the other two groups. The pathway agonist group showed significantly higher level than blank group (P <0.05). liposome nanoparticles carrying miRNA-146a inhibited the activity of STAT3 signaling, down-regulated the levels of downstream factors including TNF-a, IL-6, and TNF-a and subsequently decreased AngII and AT-1R levels, therefore playing a protective effect on VSMCs after coronary intervention.

Molecular Landscape of LncRNAs in Prostate Cancer: A focus on pathways and therapeutic targets for intervention

Background

One of the most malignant tumors in men is prostate cancer that is still incurable due to its heterogenous and progressive natures. Genetic and epigenetic changes play significant roles in its development. The RNA molecules with more than 200 nucleotides in length are known as lncRNAs and these epigenetic factors do not encode protein. They regulate gene expression at transcriptional, post-transcriptional and epigenetic levels. LncRNAs play vital biological functions in cells and in pathological events, hence their expression undergoes dysregulation.

Aim of review

The role of epigenetic alterations in prostate cancer development are emphasized here. Therefore, lncRNAs were chosen for this purpose and their expression level and interaction with other signaling networks in prostate cancer progression were examined.

Key scientific concepts of review

The aberrant expression of lncRNAs in prostate cancer has been well-documented and progression rate of tumor cells are regulated via affecting STAT3, NF-κB, Wnt, PI3K/Akt and PTEN, among other molecular pathways. Furthermore, lncRNAs regulate radio-resistance and chemo-resistance features of prostate tumor cells. Overexpression of tumor-promoting lncRNAs such as HOXD-AS1 and CCAT1 can result in drug resistance. Besides, lncRNAs can induce immune evasion of prostate cancer via upregulating PD-1. Pharmacological compounds such as quercetin and curcumin have been applied for targeting lncRNAs. Furthermore, siRNA tool can reduce expression of lncRNAs thereby suppressing prostate cancer progression. Prognosis and diagnosis of prostate tumor at clinical course can be evaluated by lncRNAs. The expression level of exosomal lncRNAs such as lncRNA-p21 can be investigated in serum of prostate cancer patients as a reliable biomarker.