Melatonin suppresses Akt/mTOR/S6K activity, induces cell apoptosis, and synergistically inhibits cell growth with sunitinib in renal carcinoma cells via reversing Warburg effect.

BACKGROUND: Metabolic alteration drives renal cell carcinoma (RCC) development, while the impact of melatonin (MLT), a neurohormone secreted during darkness, on RCC cell growth and underlying mechanisms remains unclear. METHODS: We detected concentration of metabolites through metabolomic analyses using UPLC-MS/MS, and the oxygen consumption rate was determined using the Seahorse Extracellular Flux analyzer. RESULTS: We observed that MLT effectively inhibited RCC cell growth both in vitro and in vivo. Additionally, MLT increased ROS levels, suppressed antioxidant enzyme activity, and induced apoptosis. Furthermore, MLT treatment upregulated key TCA cycle metabolites while reducing aerobic glycolysis products, leading to higher oxygen consumption rate, ATP production, and membrane potential. Moreover, MLT treatment suppressed phosphorylation of Akt, mTOR, and p70 S6 Kinase as well as the expression of HIF-1α/VEGFA in RCC cells; these effects were reversed by NAC (ROS inhibitors). Conversely, MLT synergistically inhibited cell growth with sunitinib and counteracted the Warburg effect induced by sunitinib in RCC cells. CONCLUSIONS: In conclusion, our results indicate that MLT treatment reverses the Warburg effect and promotes intracellular ROS production, which leads to the suppression of Akt/mTOR/S6K signaling pathway, induction of cell apoptosis, and synergistically inhibition of cell growth with sunitinib in RCC cells. Overall, this study provides new insights into the mechanisms underlying anti-tumor effect of MLT in RCC cells, and suggests that MLT might be a promising therapeutic for RCC.

Erratum: KLF5 downregulation desensitizes castration-resistant prostate cancer cells to docetaxel by increasing BECN1 expression and inducing cell autophagy: Erratum.

[This corrects the article DOI: 10.7150/thno.33282.].

Lung transcriptome analysis for the identification of genes involved in the hypoxic adaptation of plateau pika (Ochotona curzoniae).

The plateau pika, a typical hypoxia-tolerant mammal lives 3000-5000 m above sea level on the Qinghai-Tibet Plateau, has acquired many physiological and morphological characteristics and strategies in its adaptation to sustained, high-altitude hypoxia. Blunted hypoxic pulmonary vasoconstriction is one such strategy, but the genes involved in this strategy have not been elucidated. Here, we investigated the genes involved and their expression profiles in the lung transcriptome of plateau pikas subjected to different hypoxic conditions (using low-pressure oxygen cabins). A slight, right ventricular hypertrophy was observed in pikas of the control group (altitude: 3200 m) vs. those exposed to 5000 m altitude conditions for one week. Our assembly identified 67,774 genes; compared with their expression in the control animals, 866 and 8364 genes were co-upregulated and co-downregulated, respectively, in pikas subjected to 5000 m altitude conditions for 1 and 4 w. We elucidated pathways that were associated with pulmonary vascular arterial pressure, including vascular smooth muscle contraction, HIF-1 signalling, calcium signalling, cGMP-PKG signalling, and PI3K-Akt signalling based on the differentially expressed genes; the top-100 pathway enrichments were found between the control group and the group exposed to 5000 m altitude conditions for 4 w. The mRNA levels of 18 candidate gene showed that more than 83% of genes were expressed and the number of transcriptome The up-regulated genes were EPAS1, Hbα, iNOS, CX40, CD31, PPM1B, HIF-1α, MYLK, Pcdh12, Surfactant protein B, the down-regulated genes were RYR2, vWF, RASA1, CLASRP, HIF-3α. Our transcriptome data are a valuable resource for future genomic studies on plateau pika.

HOTAIR and androgen receptor synergistically increase GLI2 transcription to promote tumor angiogenesis and cancer stemness in renal cell carcinoma.

Tumor angiogenesis is a major characteristic of renal cell carcinoma (RCC). Herein, we report a novel mechanism of how lncRNA and androgen receptor (AR) drive the Hedgehog pathway to promote tumor angiogenesis in RCC. We found that the high expression of lncRNA HOTAIR in RCC is associated with poor prognosis. Moreover, HOTAIR and AR form a feedback loop to promote the expression of each other. Interestingly, we also found that in RCC, HOTAIR is associated with the Hedgehog pathway, especially GLI2, via bioinformatics analysis. Furthermore, HOTAIR promotes GLI2 expression in the presence of AR. Mechanistically, HOTAIR interacts with AR and they cooperatively bind to GLI2 promoter and increase its transcription activity. We further confirmed how HOTAIR-AR axis regulates GLI2 expression by analyzing its function in RCC cells and found that HOTAIR and AR synergistically enhanced the expression of GLI2 downstream genes, such as VEGFA, PDGFA, and cancer stem cell transcription factors, and promoted tumor angiogenesis and cancer stemness in RCC cells both in vitro and in tumor xenografts. Overall, these findings suggest that HOTAIR and GLI2 could be novel therapeutic targets against RCC.

Downregulation of Collagen COL4A6 Is Associated with Prostate Cancer Progression and Metastasis.

Aims: To determine the association between collagen type IV alpha 6 (COL4A6) expression levels and prostate cancer invasion and metastasis. Methods: We analyzed three Gene Expression Omnibus (GEO) datasets through the GEO2R online tool to obtain the set of differentially expressed genes (DEGs) between malignant and nonmalignant prostate tissues, and further analyzed the COL4A6 gene's expression in databases. Western blot assays, real-time quantitative polymerase chain reaction analysis, and immunofluorescence staining were used to detect COL4A6 gene expression. Wound healing assays and cell invasion transwell assays were performed to measure cell invasion and siRNA was used to knock down COL4A6 gene expression. Results: Through the use of bioinformatic tools we showed that the COL4A6 gene is one of the highly downregulated genes in prostate cancer; additionally, hypermethylation of the COL4A6 promoter in prostate cancer is correlated with lower expression levels. We also showed that downregulation of COL4A6, which activates the p-FAK/MMP-9 signaling pathway in prostate cancer cells, is associated with prostate cancer cell metastasis based on data retrieved from The Cancer Genome Atlas (TCGA) and GEO databases. Finally, we found that the COL4A6 protein is localized extracellularly and its expression is positively correlated with disease-free survival of prostate cancer patients. Conclusion: Our results indicate that downregulation of COL4A6 may promote prostate cancer progression and invasion. Additionally, COL4A6 and its promoter methylation status could be valuable markers for prostate cancer prognoses.

KLF5 inhibits STAT3 activity and tumor metastasis in prostate cancer by suppressing IGF1 transcription cooperatively with HDAC1.

KLF5 is frequently deleted and downregulated in prostate cancer, and recently it has been reported that KLF5 loss is enriched in the aggressive branches of prostate cancer evolution. However, why KLF5 loss is associated with prostate cancer aggressiveness is still not clear. Herein, we analyzed KLF5 expression in TCGA and GEO database, as well as prostate cancer tissue microarray, and found that KLF5 expression significantly decreased in prostate cancer accompanying with tumor progression; moreover, KLF5 downregulation was associated with shorter survival of patients. Interestingly, we also found that KLF5 expression was obviously lower in prostate cancer metastases than in localized tissues, indicating that KLF5 downregulation is associated with prostate cancer invasion and metastasis. To assess this effect of KLF5, we knocked down KLF5 in prostate cancer cells and found that KLF5 knockdown promoted invasive ability of prostate cancer cells in vitro and in vivo. Moreover, we found that KLF5 downregulation enhanced the expression of IGF1 and STAT3 phosphorylation, while block of IGF1 with antibody decreased the enhancement of STAT3 activity and prostate cancer cell invasive ability by KLF5 knockdown, indicating that KLF5 inhibits prostate cancer invasion through suppressing IGF1/STAT3 pathway. Mechanistically, we found that KLF5 interacted with deacetylase HDAC1 and KLF5 is necessary for the binding of HDAC1 on IGF1 promoter to suppress IGF1 transcription. Taken together, our results indicate that KLF5 could be an important suppressor of prostate cancer invasion and metastasis, because KLF5 could suppress the transcription of IGF1, a tumor cell autocrine cytokine, and its downstream cell signaling to inhibit cell invasive ability, and reveal a novel mechanism for STAT3 activation in prostate cancer. These findings may provide evidence for the precision medicine in prostate cancer.

[Dynamic evaluation and driving forces of ecosystem services in Quanzhou bay estuary wetland, China]. / 泉州湾河口湿地生态系统服务价值的动态评价及驱动力分析.

Ecosystem service value (ESV) in 1997, 2005, 2013 and 2015 of Quanzhou Bay estuary wetland was evaluated dynamicly by market value, alternative value and opportunity cost methods, combined with classification of service indicators and deduplicate computing. The main driving forces for the changes of ESV and the pathway and intensity of their actions were identified using stepwise regression and path analysis methods. The results showed that the main ecosystem services of Quanzhou Bay estuary wetland were flood regulation, climate regulation, and food supply, which were directly driven by water supply, mariculture carrying capacity, and gross value of the regional production. Other drivers exerted indirect effect on the changes of main ESVs.

KLF5 downregulation desensitizes castration-resistant prostate cancer cells to docetaxel by increasing BECN1 expression and inducing cell autophagy.

KLF5 is frequently deleted or downregulated in prostate cancer. However, it is not known whether downregulation of KLF5 is associated with the response of prostate cancer cells to chemotherapy and/or prognosis of patients. Methods: We monitored cell growth by MTT and colony formation assays, and cell autophagy through tandem fluorescence microscopy and transmission electron microscopy. Gene expression was analyzed by RT-qPCR and Western blotting. We determined the binding of KLF5 together with HDAC3 on the beclin-1 (BECN1) promoter by the ChIP assay, oligonucleotides pulldown, and co-immunoprecipitation. The effect of docetaxel on cell growth in vivo was examined in a CWR22RV1 xenograft tumor mouse model. Results: In the present study, we found that KLF5 down-regulation was associated with progression of prostate cancer and poor prognosis of patients. KLF5 knockdown reduced the sensitivity of prostate cancer cells to docetaxel in vitro and in vivo, and docetaxel treatment decreased the expression of KLF5. Moreover, we confirmed that docetaxel treatment inhibited cell death by inducing autophagy in prostate cancer cells. Thus, we hypothesized that KLF5 could be a regulator of cell autophagy. Interestingly, KLF5 could inhibit prostate cancer cell autophagy by suppressing the transcription of BECN1 cooperatively with HDAC3. Another significant finding was that docetaxel treatment repressed KLF5 expression through AMPK/mTOR/p70S6K signaling pathway resulting in increased BECN1, induction of cell autophagy, and promotion of cell survival in castration-resistant prostate cancer cells. Conclusions: Our results indicated that downregulation of KLF5 promoted cell autophagy in prostate cancer. Furthermore, reduced KLF5 also facilitated cell autophagy induced by docetaxel resulting in desensitization to the drug and cell survival. Decreased levels of KLF5 led to increased BECN1 via AMPK/mTOR/p70S6K signaling. Thus, repression of BECN1 and cell autophagy was critical for KLF5 to increase the sensitivity of prostate cancer cells to docetaxel.

Testosterone-retinoic acid signaling directs spermatogonial differentiation and seasonal spermatogenesis in the Plateau pika (Ochotona curzoniae).

During evolution, animals optimize their reproductive strategies to increase offspring survival. Seasonal breeders reproduce only during certain times of the year. In mammals, reproduction is tightly controlled by hypothalamus-pituitary-gonad axis. Although pathways regulating gametogenesis in non-seasonal model species have been well established, molecular insights into seasonal reproduction are severely limited. Using the Plateau pika (Ochotona curzoniae), a small rodent animal species native to the Qinghai-Tibetan plateau, as a model, here we report that seasonal spermatogenesis is governed at the level of spermatogonial differentiation. In testis of the reproductively dormant animals, undifferentiated spermatogonia failed to differentiate and accumulated in the seminiferous tubules. RNA-seq analyses of the active and dormant testes revealed that genes modulating retinoic acid biogenesis and steriodogenesis were differentially regulated. A single injection of all-trans retinoic acid (ATRA) reinitiated spermatogenesis and inhibition the function of RA-degrading enzyme CYP26B1 for 10 days induced spermatogonial differentiation. Strikingly, testosterone injection reinitiated spermatogenesis in short day adapted animals. Testosterone provides a permissive environment of RA biogenesis and actions in testis, therefore, indirectly controls spermatogonial differentiation. Collectively, these findings provide a key mechanistic insight regarding the molecular regulation of seasonal reproduction in mammals.

Associations between interleukin-6 gene -174 C/G and -572 C/G polymorphisms and the risk of gastric cancer: a meta-analysis.

BACKGROUND AND OBJECTIVES: Epidemiological studies have evaluated the associations between interleukin-6 (IL-6) gene -174 C/G (rs1800795) and -572 C/G (rs1800796) polymorphisms and gastric cancer (GC) risk, but results and conclusions remain controversial. In order to derive a more precise estimation of the associations, we performed this meta-analysis. METHODS: A meta-analysis was conducted to estimate the associations between IL-6 gene -174 C/G and -572 C/G polymorphisms and GC risk. RESULTS: Nine articles involving 13 studies were included in the final meta-analysis, covering a total of 1,581 GC cases and 2,563 controls. For IL-6 gene -174 C/G polymorphism, nine studies were combined showing no evidence for associations between IL-6 gene -174 C/G polymorphism and GC risk. For IL-6 gene -572 C/G polymorphism, four studies were combined. There was also lack of evidence for significant association between IL-6 gene -572 C/G polymorphism and GC risk. In addition, the similar results were obtained in the subgroup analyses and cumulative meta-analysis. CONCLUSIONS: The present meta-analysis suggests that IL-6 gene -174 C/G and -572 C/G polymorphisms are not associated with GC risk. However, due to the small subjects included in analysis and the selection bias in some studies, the results should be interpreted with caution.

Association between interleukin-10 gene -592 C/A polymorphism and the risk of type 2 diabetes mellitus: a meta-analysis of 5320 subjects.

Increasing evidence suggests that interleukin-10 (IL-10) gene -592 C/A polymorphism may be associated with an increased risk of type 2 diabetes mellitus (T2DM). To provide a quantitative assessment of the association between this variant and risk of T2DM, we performed this meta-analysis. Systematic searches of electronic databases PubMed, Embase, Web of Science, CBMdisc and CNKI, as well as hand searching of the references of identified articles were performed. A total of 2698 T2DM cases and 2622 controls in seven case-control studies were included in this meta-analysis. The results showed no evidence for significant association between IL-10 gene -592 C/A polymorphism and T2DM risk (for A allele vs. C allele: OR=0.94, 95% CI=0.69-1.29, p=0.69; for A/A vs. C/C: OR=0.88, 95% CI=0.39-1.98, p=0.75; for A/A vs. A/C+C/C: OR=1.04, 95% CI=0.59-1.82, p=0.89; for A/A+A/C vs. C/C: OR=1.11, 95% CI=0.73-1.69, p=0.61). In addition, the similar results were obtained in the subgroup analysis based on the ethnicity. In summary, results from this meta-analysis suggest that the IL-10 gene -592 C/A polymorphism is not associated with T2DM risk.