Transition In Prostate Cancer Research Articles

Novel role of LLGL2 silencing in autophagy: reversing epithelial-mesenchymal transition in prostate cancer

PurposeProstate cancer (PCa) is a major urological disease that is associated with significant morbidity and mortality in men. LLGL2 is the mammalian homolog of Lgl. It acts as a tumor suppressor in breast and hepatic cancer. However, the role of LLGL2 and the underlying mechanisms in PCa have not yet been elucidated. Here, we investigate the role of LLGL2 in the regulation of epithelial-mesenchymal transition (EMT) in PCa through autophagy in vitro and in vivo.MethodsPC3 cells were transfected with siLLGL2 or plasmid LLGL2 and autophagy was examined. Invasion, migration, and wound healing were assessed in PC3 cells under autophagy regulation. Tumor growth was evaluated using a shLLGL2 xenograft mouse model.ResultsIn patients with PCa, LLGL2 levels were higher with defective autophagy and increased EMT. Our results showed that the knockdown of LLGL2 induced autophagy flux by upregulating Vps34 and ATG14L. LLGL2 knockdown inhibits EMT by upregulating E-cadherin and downregulating fibronectin and α-SMA. The pharmacological activation of autophagy by rapamycin suppressed EMT, and these effects were reversed by 3-methyladenine treatment. Interestingly, in a shLLGL2 xenograft mouse model, tumor size and EMT were decreased, which were improved by autophagy induction and worsened by autophagy inhibition.ConclusionDefective expression of LLGL2 leads to attenuation of EMT due to the upregulation of autophagy flux in PCa. Our results suggest that LLGL2 is a novel target for alleviating PCa via the regulation of autophagy.

The Suppression of the Epithelial to Mesenchymal Transition in Prostate Cancer through the Targeting of MYO6 Using MiR-145-5p.

Aberrant expression of miR-145-5p has been observed in prostate cancer where is has been suggested to play a tumor suppressor role. In other cancers, miR-145-5p acts as an inhibitor of epithelial-to-mesenchymal transition (EMT), a key molecular process for tumor progression. However, the interaction between miR-145-5p and EMT remains to be elucidated in prostate cancer. In this paper the link between miR-145-5p and EMT in prostate cancer was investigated using a combination of in silico and in vitro analyses. miR-145-5p expression was significantly lower in prostate cancer cell lines compared to normal prostate cells. Bioinformatic analysis of The Cancer Genome Atlas prostate adenocarcinoma (TCGA PRAD) data showed significant downregulation of miR-145-5p in prostate cancer, correlating with disease progression. Functional enrichment analysis significantly associated miR-145-5p and its target genes with EMT. MYO6, an EMT-associated gene, was identified and validated as a novel target of miR-145-5p in prostate cancer cells. In vitro manipulation of miR-145-5p levels significantly altered cell proliferation, clonogenicity, migration and expression of EMT-associated markers. Additional TCGA PRAD analysis suggested miR-145-5p tumor expression may be useful predictor of disease recurrence. In summary, this is the first study to report that miR-145-5p may inhibit EMT by targeting MYO6 in prostate cancer cells. The findings suggest miR-145-5p could be a useful diagnostic and prognostic biomarker for prostate cancer.

Nuclear receptor NURR1 functions to promote stemness and epithelial-mesenchymal transition in prostate cancer via its targeting of Wnt/β-catenin signaling pathway

Dysregulated activation of Wnt/β-catenin signaling pathway is a frequent or common event during advanced progression of multiple cancers. With this signaling activation, it enhances their tumorigenic growth and facilitates metastasis and therapy resistance. Advances show that this signaling pathway can play dual regulatory roles in the control of cellular processes epithelial-mesenchymal transition (EMT) and cancer stemness in cancer progression. Aberrant activation of Wnt/β-catenin signaling pathway is shown to be common in prostate cancer and also castration-resistant prostate cancer (CRPC). However, the transcriptional regulators of this pathway in prostate cancer are still not well characterized. NURR1 (NR4A2) is an orphan nuclear receptor and plays an important role in the development of dopaminergic neurons. Previously, we have shown that NURR1 exhibits an upregulation in isolated prostate cancer stem-like cells (PCSCs) and a xenograft model of CRPC. In this study, we further confirmed that NURR1 exhibited an upregulation in prostate cancer and also enhanced expression in prostate cancer cell lines. Functional and molecular analyses showed that NURR1 could act to promote both in vitro (cancer stemness and EMT) and also in vivo oncogenic growth of prostate cancer cells (metastasis and castration resistance) via its direct transactivation of CTNNB1 (β-catenin) and activation of β-catenin to mediate the activation of Wnt/β-catenin signaling pathway. Moreover, we also demonstrated that NURR1 activity in prostate cancer cells could be modulated by small molecules, implicating that NURR1 could be a potential therapeutic target for advanced prostate cancer management.

MLPH Accelerates the Epithelial-Mesenchymal Transition in Prostate Cancer [Retraction

[This retracts the article DOI: 10.2147/OTT.S225023.].

Retracted: FSCN1 Promotes Glycolysis and Epithelial-Mesenchymal Transition in Prostate Cancer through a YAP/TAZ Signaling Pathway.

[This retracts the article DOI: 10.1155/2022/6245647.].

Targeting of AKT1 by miR-143-3p Suppresses Epithelial-to-Mesenchymal Transition in Prostate Cancer.

An altered expression of miR-143-3p has been previously reported in prostate cancer where it is purported to play a tumor suppressor role. Evidence from other cancers suggests miR-143-3p acts as an inhibitor of epithelial-to-mesenchymal transition (EMT), a key biological process required for metastasis. However, in prostate cancer the interaction between miR-143-3p and EMT-associated mechanisms remains unclear. Therefore, this paper investigated the link between miR-143-3p and EMT in prostate cancer using in vitro and in silico analyses. PCR detected that miR-143-3p expression was significantly decreased in prostate cancer cell lines compared to normal prostate cells. Bioinformatic analysis of The Cancer Genome Atlas Prostate Adenocarcinoma (TCGA PRAD) data showed a significant downregulation of miR-143-3p in prostate cancer, correlating with pathological markers of advanced disease. Functional enrichment analysis confirmed the significant association of miR-143-3p and its target genes with EMT. The EMT-linked gene AKT1 was subsequently shown to be a novel target of miR-143-3p in prostate cancer cells. The in vitro manipulation of miR-143-3p levels significantly altered the cell proliferation, clonogenicity, migration and expression of EMT-associated markers. Further TCGA PRAD analysis suggested miR-143-3p tumor expression may be a useful predictor of disease recurrence. In summary, this is the first study to report that miR-143-3p overexpression in prostate cancer may inhibit EMT by targeting AKT1. The findings suggest miR-143-3p could be a useful diagnostic and prognostic biomarker for prostate cancer.

Growth and Migration Blocking Effect of Nanaomycin K, a Compound Produced by Streptomyces sp., on Prostate Cancer Cell Lines In Vitro and In Vivo.

Since castration-resistant prostate cancer (CRPC) acquires resistance to molecularly targeted drugs, discovering a class of drugs with different mechanisms of action is needed for more efficient treatment. In this study, we investigated the anti-tumor effects of nanaomycin K, derived from "Streptomyces rosa subsp. notoensis" OS-3966. The cell lines used were LNCaP (non-CRPC), PC-3 (CRPC), and TRAMP-C2 (CRPC). Experiments included cell proliferation analysis, wound healing analysis, and Western blotting. In addition, nanaomycin K was administered intratumorally to TRAMP-C2 carcinoma-bearing mice to assess effects on tumor growth. Furthermore, immuno-histochemistry staining was performed on excised tissues. Nanaomycin K suppressed cell proliferation in all cell lines (p < 0.001) and suppressed wound healing in TRAMP-C2 (p = 0.008). Nanaomycin K suppressed or showed a tendency to suppress the expression of N-cadherin, Vimentin, Slug, and Ras in all cell lines, and suppressed the phosphorylation of p38, SAPK/JNK, and Erk1/2 in LNCaP and TRAMP-C2. In vivo, nanaomycin K safely inhibited tumor growth (p = 0.001). In addition, suppression of phospho-Erk1/2 and increased expression of E-cadherin and cleaved-Caspase3 were observed in excised tumors. Nanaomycin K inhibits tumor growth and suppresses migration by inhibiting epithelial-mesenchymal transition in prostate cancer. Its mechanism of action is related to the inhibition of phosphorylation of the MAPK signaling pathway.

Megakaryocyte-Derived IL-8 Acts as a Paracrine Factor for Prostate Cancer Aggressiveness through CXCR2 Activation and Antagonistic AR Downregulation.

Prostate cancer is the fifth leading cause of cancer-related mortality in men, primarily because of treatment resistance, recurrence, and metastasis. In the present study, we investigated the role of paracrine interleukin-8 (IL-8) in the antagonistic expression of IL-8 and androgen receptor (AR), and the contribution of IL-8 to prostate cancer aggressiveness. In hormone-responsive LNCaP cells that do not express IL-8, recombinant IL-8 treatment significantly increased expressions of IL-8, CXC chemokine receptor 2 (CXCR2), matrix metalloproteinase (MMP)-2/9, Snail, and vimentin. IL-8 treatment significantly decreased AR and E-cadherin expression. IL-8-induced gene expression changes were suppressed by navarixin, a CXCR1/2 inhibitor, and gallein, a Gβγ inhibitor. In PC-3 androgen-refractory prostate cancer cells, IL-8 knockdown reduced expressions of CXCR2, MMP-2/9, Snail, and vimentin, and increased AR and E-cadherin expressions at the mRNA and protein levels. Co-culture with MEG-01 human megakaryocytic cells secreting high levels of IL-8 induced gene expression changes in both LNCaP and PC-3 cells, similar to those induced by IL-8 treatment. The altered gene expressions were accompanied by significant activation of transcription factor Snail in LNCaP and PC-3 cells. Treatment with the CXCR blocker navarixin inhibited the invasion of PC-3 cells but not LNCaP cells. However, invasion induced by MEG-01 was inhibited by navarixin in both LNCaP and PC-3 cells. The collective findings demonstrate that IL-8 enhances CXCR2 expression, which antagonistically regulates AR expression. More importantly, through changes in IL-8/CXCR2-regulated gene expression, IL-8 induces antiandrogen therapy resistance and epithelial-mesenchymal transition in prostate cancer.

LncRNA SSTR5-AS1 as a Prognostic Marker Promotes Cell Proliferation and Epithelial-to-Mesenchymal Transition in Prostate Cancer.

This study is aimed to investigate the clinical significance and biological function of long non-coding RNA somatostatin receptor 5 antisense RNA 1 (SSTR5-AS1) in prostate cancer (PCa). Here, we found that SSTR5-AS1 expression was upregulated in PCa tissues compared with adjacent tissues using quantitative real time PCR analysis. The results from Chi-square test showed that increased SSTR5-AS1 expression levels were correlated with preoperative prostate specific antigen, tumor stage and lymph node metastasis. Kaplan-Meier survival curve described patients with high SSTR5-AS1 expression level showed poor survival. Univariate and multivariate cox regression analysis further identified SSTR5-AS1 expression as a poor independent prognostic factor for PCa patients. Cell Counting Kit-8 (CCK-8) assay, 5-ethynyl-2'-deoxyuridine incorporation assay, wound-healing assay and Transwell assay were performed to investigate the functional role of SSTR5-AS1 in PCa cells. The in vitro results indicated that SSTR5-AS1 knockdown inhibited, while SSTR5-AS1 overexpression promoted the proliferation, migration, and invasion of PCa cells. At molecular level, SSTR5-AS1 knockdown downregulated the protein levels of proliferating cell nuclear antigen, N-cadherin and vimentin, and upregulated E-cadherin expression in PC-3 cells. SSTR5-AS1 overexpression obtained opposite results on these protein markers in DU145 cells. In conclusion, these findings indicated that SSTR5-AS1 promotes PCa cell behaviors, which might provide a potential therapeutic target for PCa patients.

FOXA2 Promotes Prostate Cancer Lineage Plasticity through KIT.

FOXA2 drives the adeno-to-neuroendocrine lineage transition in prostate cancer through KIT activation.

Sasanquasaponin inhibited epithelial to mesenchymal transition in prostate cancer by regulating the PI3K/Akt/mTOR and Smad pathways

Context Sasanquasaponin (SQS) is a commonly used traditional Chinese medicine proved to have a wide range of pharmacological functions. Objective The objective of this study is to explore the effect and underlying mechanism of SQS in the treatment of prostate cancer (PC). Materials and methods PC cell lines (22Rv1 and PC-3) were treated with SQS (0, 0.5, 1, 2, and 4 μM) for 12 or 24 h. The viability of cells was evaluated, while the mRNA and protein levels of epithelial to mesenchymal transition (EMT)-related genes in PC cell lines were measured (Groups: Control, TGF-β1, TNF-α, TGF-β1 + TNF-α, and TGF-β1 + TNF-α + SQS). The migration and invasion abilities of PC cell lines were evaluated (Groups: Control, SQS). Finally, the antitumour effect of SQS (25, 50,100, and 200 mg/kg) in BALB/c nude mice (6 weeks, 18–20 g) was evaluated (Groups: Control, Vehicle, 25, 50,100, and 200 mg/kg SQS). The study duration was 1 month. Results SQS inhibited the viability and the number of colonies of 22Rv1 or PC-3 cells. The IC50 of SQS of 12 and 24 h in these two cells was 3.25, 1.82, 4.76, and 4.70 μM, respectively. SQS inhibited the adhesion, migration, and invasion of PC cells. It also inhibited the expression of EMT-related markers of PC cells. The PI3K/Akt/mTOR and Smad2/3 signalling pathways were activated in the process of EMT, and SQS could significantly reduce the activation of the PI3K/Akt/mTOR and Smad2/3 pathways. Finally, SQS inhibited the growth of xenograft tumours in vivo. Conclusions SQS inhibited EMT in PC by regulating the PI3K/Akt/mTOR and Smad pathways.

FSCN1 Promotes Glycolysis and Epithelial-Mesenchymal Transition in Prostate Cancer through a YAP/TAZ Signaling Pathway.

Objective The aim of the study is to investigate the role and possible mechanism of fascin-1 (FSCN1) in the invasion, migration, glycolysis, and epithelial-mesenchymal transition (EMT) of prostate cancer. Methods Real-time quantitative polymerase chain reaction (qRT-PCR) was utilized to determine the mRNA expression level of FSCN1 in prostate cancer tissues and prostate cancer cells PC-3 and DU145. The transwell and the scratch test were applied to detect the invasion and migration abilities of cells, respectively. A metabolic assay was used for measuring the glucose consumption, lactate production, and the extracellular acidification rate (ECAR) in cells; western blot was used for checking FSCN1, EMT, and yes-associated protein/transcriptional co-activators with the PDZ-binding motif (YAP/TAZ) signaling pathway-related protein expression level in cells or tissues. Results FSCN1 was significantly highly expressed in prostate cancer tissues and cells. On the one hand, interference with the expression of FSCN1 could inhibit the invasion, migration, EMT, and glycolysis of prostate cancer cells. On the other hand, overexpression of FSCN1 promoted the invasion, migration, EMT, and glycolysis of prostate cancer cells. Besides, further mechanistic studies revealed that FSCN1 could activate the YAP/TAZ signaling pathway in prostate cancer cells. Conclusion FSCN1 promotes invasion, migration, EMT, and glycolysis in prostate cancer cells by activating the YAP/TAZ signaling pathway. FSCN1 may be used as a biomarker for the diagnosis or treatment in prostate cancer.

Silencing Akt1 enhances the resistance of prostate cancer cells to starvation and inhibits starvation-induced lung metastasis through epithelial-mesenchymal transition in prostate cancer.

Nutritional starvation (NST) is the basis of tumor anti-angiogenesis and metabolic therapy strategy. Silencing Akt1 inhibits prostate cancer (PCa) cells growing; slow-growing cells tend to consume less nutrition. It is suggested that Akt1-silenced cancer cells will have a more substantial tolerance to NST. Clarify this critical question is vital for tumor treatment strategies based on Akt1 and NST. The Akt1 gene of PC3 and DU145 cells was silenced by lent-virus. NST model was established by serum stripping. Cell viability was detected by MTT assay and cell counting method. Apoptosis was detected by TUNEL and flow cytometry, and cell invasion was determined by transwells and ECIS. The markers of epithelial-mesenchymal transition (EMT) were detected by western blotting. PCa lung metastasis model was established by tail vein injection and quantified by Indian ink and GFP fluorescence. Silencing Akt1 slowed down the decrease of cell number and increase of apoptosis caused by NST. Silencing Akt1 with NST exposure in PCa cells could down-regulate epithelial markers (E-cadherin, claudin-5, and ZO-1) and up-regulate mesenchymal markers N-cadherin and EMT regulators Snail. Although silencing Akt1 enhanced the invasion of PCa cells induced by NST in vitro, silencing Akt1 inhibited the PCa lung metastasis induced by NST in vivo. Silencing Akt1 gene enhances the resistance of PCa cells to NST. The invasion results in vitro were inconsistent with those metastases in vivo, which may be related to a combination of NST with silencing Akt1 to maintain the mesenchymal state of PCa cells through EMT.

DNMT3A epigenetically regulates key microRNAs involved in epithelial-to-mesenchymal transition in prostate cancer.

Epithelial-to-mesenchymal transition (EMT) is involved in prostate cancer (PCa) metastatic progression, and its plasticity suggests epigenetic implications. Deregulation of DNA methyltransferases (DNMTs) and several microRNAs (miRNAs) plays a relevant role in EMT, but their interplay has not been clarified yet. In this study, we provide evidence that DNMT3A interaction with several miRNAs has a central role in an ex vivo EMT PCa model obtained via exposure of PC3 cells to conditioned media from cancer-associated fibroblasts. The analysis of the alterations of the miRNA profile shows that miR-200 family (miR-200a/200b/429, miR-200c/141), miR-205 and miR-203, known to modulate key EMT factors, are down-regulated and hyper-methylated at their promoters. DNMT3A (mainly isoform a) is recruited onto these miRNA promoters, coupled with the increase of H3K27me3/H3K9me3 and/or the decrease of H3K4me3/H3K36me3. Most interestingly, our results reveal the differential expression of two DNMT3A isoforms (a and b) during ex vivo EMT and a regulatory feedback loop between miR-429 and DNMT3A that can promote and sustain the transition towards a more mesenchymal phenotype. We demonstrate the ability of miR-429 to target DNMT3A 3'UTR and modulate the expression of EMT factors, in particular ZEB1. Survey of the PRAD-TCGA dataset shows that patients expressing an EMT-like signature are indeed characterized by down-regulation of the same miRNAs with a diffused hyper-methylation at miR-200c/141 and miR-200a/200b/429 promoters. Finally, we show that miR-1260a also targets DNMT3A, although it does not seem to be involved in EMT in PCa.

Abstract 2152: EHMT1 activity to repress neuroendocrine differentiation of prostate cancer is mediated by dual lysine-methylation

Abstract Background: Lysine methylation is an important post-translational regulation on histones, but its molecular functions on non-histone proteins remain largely unknown. In a pilot study, we identified novel lysine methylations at non-histone proteins in prostate cancer (PCa) cells through an affinity pull-down assay. EHMT1/GLP, containing monomethylated K450 and K451, was one of these proteins, and it was known to repress transcription through methylating histone 3 lysine 9 (H3K9). EHMT1 and EHMT2/G9a are members of the REST (NRSF) repressor complex, that includes LSD1/CoREST/HDACs and represses neuronal genes in non-neuronal cells. Loss of function for this complex has been indicated as a mechanism to drive neuroendocrine (NE) transition of PCa. We hypothesize that the K450/451 methylations may inhibit the activity of EHMT1 and that LSD1 and other lysine demethylase(s) may sequentially demethylate these lysines and thus induce EHMT1 activity to silence the expression of NE related genes. Methods: LNCaP stable cell lines overexpressing doxycycline-regulated V5-tagged EHMT1-WT, K450R, K451R, and K450/451R were generated. We performed ChIP-seq analyses of V5 and H3K9me2, and RNA-seq analyses in all four cell lines treated with/out doxycycline. We also conducted in vitro demethylation assays to examine whether LSD1 directly demethylates EHMT1. Moreover, we performed co-immunoprecipitation assays to determine the effect of LSD1 inhibition on the interaction of LSD1 with EHMT1. Neuronal target gene expression was examined through ChIP and mRNA analysis. Results: Using mass-spectrometry analysis, we confirmed K450 and K451 methylations of EHMT1 in LNCaP PCa cell line. The demethylation assays indicated that methylated K450 but not K451 is a potential substrate of LSD1. Moreover, LSD1 interacts with K450/451R mutant but not EHMT1-WT. Importantly, only K450/451R mutant had a significant increase of chromatin binding in V5 and elevated levels of H3K9me2 compared to the weak chromatin binding seen in WT, K450R and K451R. Analyses in RNA-Seq revealed that the K450/K451R mutant repressed genes enriched for neuronal pathways, which was not seen in WT, K450R or K451R. Conclusions: Our studies suggest that both K450 and K451 of EHMT1 are methylated in PCa cells. K450-methylation of EHMT1 can be specifically demethylated by LSD1, but this alone is not sufficient to induce the chromatin recruitment of EHMT1. However, demethylation at both K450/K451 can dramatically increase the chromatin binding of EHMT1, which subsequently represses neuronal pathways. This mechanism may be particularly important for maintaining the cell lineage of adenocarcinoma of PCa and loss of this demethylation might lead to the emergence of NE-like PCa. Citation Format: Anna Besschetnova, Wanting Han, Mingyu Liu, Dong Han, Shuai Gao, Changmeng Cai. EHMT1 activity to repress neuroendocrine differentiation of prostate cancer is mediated by dual lysine-methylation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2152.

MiR-221 regulates proliferation, invasion, apoptosis and progression of prostate cancer cells by modulating E-cadherin/Wnt/β catenin axis

MicroRNA-221 (miR-221) is aberrantly expressed in various tumours including prostate carcinoma and can act as either tumour suppressor or oncogene depending on the tumour system and stage. Epithelial-mesenchymal transition (EMT) is a plastic transition in tumour progression characterized by decreased expression of epithelial markers and increased expression of mesenchymal markers and has been known to play a critical role in promoting metastases. In this study, we have demonstrated the functional role of miR-221 in regulating epithelial-mesenchymal transition in prostate cancer. Expression of miR-221 was found to be downregulated in androgen-independent prostate cancer cells and was found to be inversely correlated with EMT. Ectopic expression of miR-221 potentially inhibited invasion and migration of androgen-independent prostate cancers cells and inhibition of miR-221 expression rescued the anti-invasive effects of miR-221. Flow cytometric analysis further revealed that miR-221 could induce cell cycle arrest with simultaneous induction of apoptosis. Additionally, transfection with miR-221 mimic upregulated negative regulators of Wnt/β catenin pathway such as GSK-3β thereby inhibiting it and downregulated mesenchymal markers viz., N-cadherin and Vimentin with simultaneous upregulation of epithelial marker E-cadherin as revealed by real-time PCR and Western blot analysis. A study using xenograft model further confirmed the anti-tumorigenic and anti-metastatic role of miR-221 in prostate cancer. We believe that his study is the first report documenting the miR-221- Wnt/β catenin signaling-EMT regulatory circuit in prostate cancer.

MicroRNA-4287 is a novel tumor suppressor microRNA controlling epithelial-to mesenchymal transition in prostate cancer.

Prostate cancer (PCa) is a significant cause of male morbidity in the United States. Despite recent advances in diagnosis and therapeutic interventions, significant fraction of cases still progress to an advanced stage. Various genetic/epigenetic elements that facilitate this progression are not yet completely known and the mechanism that favors advanced disease is an area of investigation. A characteristic feature associated with progressive disease is deletion of chromosome 8p (chr8p) region, that harbors tumor-suppressor NKX3.1. Previous studies from our group has shown that there are cluster of microRNAs (miRNAs) located within this region whose loss favors advanced, metastatic disease. miR-4287 is a novel miRNA located within this region that has not been studied before. In the present study, we analyzed the role of miR-4287 in PCa using clinical tissues and cell lines. We observed that miR-4287 is significantly downregulated in patient-derived tumor tissues. Receiver operating curve (ROC) analysis showed that miR-4287 distinguishes prostate cancer from normal with a specificity of 88.24% and with an Area under the curve (AUC) of 0.66. Further, we found that miR-4287 levels correlate inversely with patients’ serum prostate-specific antigen levels. Ectopic over-expression of miR-4287 in PCa cell lines showed that miR-4287 plays a tumor suppressor role. miR-4287 led to an increase in G2/M phase of cell cycle in PCa cell lines. Further, ectopic miR-4287 inhibited PCa epithelial-to-mesenchymal transition (EMT) by directly repressing SLUG and stem cell marker CD44. Since miR-4287 specifically targets metastasis pathway mediators, miR-4287 has potential diagnostic and therapeutic significance in preventing advanced, metastatic disease.

Metformin suppressed tumor necrosis factor-α-induced epithelial-mesenchymal transition in prostate cancer by inactivating the NF-κB signaling pathway.

BackgroundEpithelial-mesenchymal transition (EMT) and the tumor micro- environment are involved in tumorigenesis and progression. Tumor necrosis factor-α (TNF-α) is a proinflammatory cytokine in cancer that might be associated with promoting cancer invasion and metastasis. This study aimed to explore the potential effects of metformin on TNF-α-induced EMT in prostate cancer.MethodsTNF-α, NF-κB-P65 and E-cadherin were detected in prostate cancer and benign prostatic hyperplasia (BPH) tissues by immunohistochemistry. Prostate cancer PC3 cells were treated with TNF-α with or without metformin. Then, the cell invasion and cell proliferation ability was separately determined by scratch assay and invasion assay. The expression of E-cadherin, N-cadherin, Vimentin, TNF-α, NF-κB-P65, p-IKK and p-IκBα were detected by western blotting and immunofluorescence.ResultsTNF-α and NF-κB-P65 were positively related to higher Gleason scores, but E-cadherin was negatively related to higher Gleason scores. TNF-α significantly increased the migration and invasion ability of prostate cancer cells, and it significantly promoted the expression of N-cadherin, Vimentin, NF-κB-P65, p-IKK and p-IκBα but reduced the expression of E-cadherin. Metformin significantly inhibited TNF-α-induced migration and invasion of prostate cancer cells. Furthermore, metformin decreased TNF-α-induced expression of N-cadherin, Vimentin, NF-κB-P65, p-IKK and p-IκBα but increased the expression of E-cadherin. Moreover, metformin inhibited NF-κB-P65 translocation into the nucleus.ConclusionsTNF-α accelerated the EMT process potentially via activation of the NF-κB signaling pathway. Metformin might suppress TNF-α-induced EMT in prostate cancer by inactivating the NF-κB signaling pathway.

MicroRNA‑137 regulates hypoxia‑mediated migration and epithelial‑mesenchymal transition in prostate cancer by targeting LGR4 via the EGFR/ERK signaling pathway.

MicroRNAs (miRs) serve an integral role in prostate cancer. The present study aimed to investigate the effects and mechanisms of miR‑137 in hypoxia‑mediated migration and epithelial‑mesenchymal transition (EMT). PC3 and DU145 prostate cancer cells were exposed to hypoxia for 24h, after which the expression of miR‑137 was determined by reverse transcription‑quantitative PCR (RT‑qPCR). The cells were transfected with a miR‑137 mimic or inhibitor, followed by hypoxia exposure. The results demonstrated that hypoxia reduced miR‑137 expression. Further results from the Cell Counting Kit‑8, Cell Death Detection ELISA plus kit, Transwell assay, RT‑qPCR and western blotting assays revealed that the miR‑137 mimic prevented cell proliferation, facilitated apoptosis and repressed cell migration, invasiveness, and expression of N‑cadherin, vimentin and matrix metalloproteinase 2; the miR‑137 inhibitor exerted the opposite effects. A dual‑-luciferase reporter assay determined that miR‑137 directly targeted leucine‑rich repeat‑containing G protein‑coupled receptor4 (LGR4). Additionally, miR‑137 negatively regulated the epidermal growth factor receptor/extracellular signal‑-regulated kinase (EGFR/ERK) signaling pathway by targeting LGR4. LGR4 silencing or EGFR/ERK inhibition abolished the effects of miR‑137 inhibitor on cell migration and EMT. In conclusion, by targeting LGR4 via the EGFR/ERK signaling pathway, miR‑137 inhibited prostate cancer cell migration and EMT.

CircHIPK3 Facilitates the G2/M Transition in Prostate Cancer Cells by Sponging miR-338-3p.

BackgroundCircular RNAs (circRNAs) play a crucial role in gene expression regulation. CircHIPK3 is a circRNA derived from Exon 2 of HIPK3 gene and its role in prostate cancer (PCa) is still unclear.MethodsCCK8 assays, flow cytometry and colony formation assays were performed to assess the effects of circHIPK3 in PCa cells. Bioinformatics analysis, RNA pull-down assay, RNA immunoprecipitation assay (RIP), and luciferase activity assay were performed to dissect the mechanism underlying circHIPK3-mediated G2/M transition in PCa cells.ResultsCircHIPK3 expression was upregulated in PCa cells and prostate cancer tissues. Overexpression of circHIPK3 or circHIPK3 silencing altered PCa viability, proliferation and apoptosis in vitro. CircHIPK3 could sponge miR-338-3p and inhibit its activity, resulting in increased expression of Cdc25B and Cdc2 in vitro.ConclusionCircHIPK3 promotes G2/M transition and induces PCa cell proliferation by sponging miR-338-3p and increasing the expression of Cdc25B and Cdc2. CircHIPK3 may play an oncogenic role in PCa.