Androgen receptor-regulated circFNTA activates KRAS signaling to promote bladder cancer invasion.

The androgen receptor (AR) has been linked to bladder cancer (BCa) progression, but if this involves circular RNAs (circRNAs) remains unclear. Here, we find that AR alters the levels of circRNA-FNTA (circFNTA) to increase BCa cell invasion and chemo-resistance. Mechanistically, AR represses the RNA editing gene ADAR2 via direct binding to its 5' promoter region to increase circFNTA levels, which then sponges the microRNA miR-370-3p to increase the expression of its host gene FNTA. This AR-mediated ADAR2/circFNTA/miR-370-3p/FNTA pathway then activates KRAS signaling to alter BCa cell invasion and chemo-sensitivity to cisplatin. A clinical BCa sample survey shows that circFNTA expression is elevated in BCa tissues, and results from a BCa mouse model indicate that depletion of circFNTA leads to the suppression of BCa metastases and increased cisplatin chemo-sensitivity. Together, based on our results using multiple BCa cell lines and an in vivo mouse model we suggest that targeting this newly identified AR/ADAR2/circFNTA/miR-370-3p/FNTA/KRAS axis may lead to the development of therapies to suppress BCa metastasis and to increase its chemo-sensitivity.

Comprehensive characterization of immune- and inflammation-associated biomarkers based on multi-omics integration in kidney renal clear cell carcinoma.

BACKGROUND: Kidney renal clear cell carcinoma (KIRC) is the most common type of kidney cancer in adults, and it is responsible for approximately 90-95% of cases. Although extensive evidence has suggested that many immune- and inflammation-related genes could serve as effective biomarkers in KIRC, the potential associations among immune-, inflammation- and KIRC-related genes has not been sufficiently understood. METHODS: Here, we integrated multiple levels of data to construct an immune-, inflammation- or KIRC-directed neighbour network (IIKDN network) and a KIRC-related gene-directed network (KIRCD network). RESULTS: Our analysis suggested that immune- and inflammation-related genes in the network have special topological characteristics and expression patterns related to KIRC. We further identified five core clusters that showed a tighter network structure and stronger correlation of expression from the KIRCD network. Specifically, multiple-level molecular characteristics were systematically portrayed, including somatic mutation, copy-number variant and DNA methylation for the genes in five core clusters. We discovered that the genes showed strong correlation with respect to the expression and methylation levels in these five core clusters. These five core clusters could become special prognostic biomarkers for KIRC, and functional analysis showed that they were associated with activation of the immune and inflammation systems and cancer progression. CONCLUSIONS: Our findings highlighted the novel role of the immune and inflammation genes in KIRC.

Downregulation of UBB potentiates SP1/VEGFA-dependent angiogenesis in clear cell renal cell carcinoma.

Clear cell renal cell carcinoma (ccRCC) presents a unique profile characterized by high levels of angiogenesis and robust vascularization. Understanding the underlying mechanisms driving this heterogeneity is essential for developing effective therapeutic strategies. This study revealed that ubiquitin B (UBB) is downregulated in ccRCC, which adversely affects the survival of ccRCC patients. UBB exerts regulatory control over vascular endothelial growth factor A (VEGFA) by directly interacting with specificity protein 1 (SP1), consequently exerting significant influence on angiogenic processes. Subsequently, we validated that DNA methyltransferase 3 alpha (DNMT3A) is located in the promoter of UBB to epigenetically inhibit UBB transcription. Additionally, we found that an unharmonious UBB/VEGFA ratio mediates pazopanib resistance in ccRCC. These findings underscore the critical involvement of UBB in antiangiogenic therapy and unveil a novel therapeutic strategy for ccRCC.

The categorizations of vasculogenic mimicry in clear cell renal cell carcinoma unveil inherent connections with clinical and immune features.

Background: Clear cell renal cell carcinoma (ccRCC) stands as the prevailing variant kidney cancer in humans. Unfortunately, patients with disseminated RCC at diagnosis often have a diminished prognosis. Rapid tumor growth necessitates efficient blood supply for oxygen and nutrients, involving the circulation of blood from vessels to tumor tissues, facilitating tumor cell entry into the extracellular matrix. Vasculogenic mimicry (VM) significantly contributes to tumor growth and metastasis. Within this investigation, we identified vasculogenic mimicry-related genes (VMRGs) by analyzing data from 607 cases of kidney renal clear cell carcinoma (KIRC) in The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) database (https://www.ncbi.nlm.nih.gov/geo/). These findings offer insights into ccRCC progression and metastasis. Method: We identified VMRGs-related subtypes using consistent clustering methods. The signature of the VMRGs was created using univariate Cox regression and LASSO Cox regression analyses. To evaluate differences in immune cell infiltration, we employed ssGSEA. Afterwards, we created an innovative risk assessment model, known as the VM index, along with a nomogram to forecast the prognosis of ccRCC. Additionally, we verified the expression of an important gene related to VM, peroxiredoxin 2 (PRDX2), in tissue samples. Furthermore, we assessed the sensitivity to drugs in various groups by utilizing the pRRophetic R package. Results: Significant predictors of survival rates in both high- and low-risk groups of KIRC patients were identified as VMRGs. The independent prognostic factors for RCC were confirmed by both univariate and multivariate Cox regression analyses, validating VMRG risk signatures. Differences were observed in drug sensitivity, immune checkpoint expression, and responses to immune therapy between patients classified into high- and low-VMRG-risk groups. Our nomograms consistently demonstrated precise predictive capabilities. Finally, we experimentally verified PRDX2 expression levels and their impact on prognosis. Conclusion: The signature predicts patient prognosis and therapy response, laying the groundwork for future clinical strategies in treating ccRCC patients.

Investigating the potential clinical significance of long non-coding RNA 00092 in patients with breast cancer.

Background: Aberrant promoter methylation and its resultant aberrant gene expression are important epigenetic mechanisms that promote the development of breast cancer (BC). However, the prognostic value of this type of methylation-driven gene in BC is unknown. Methods: To identify DNA methylation-driven long non-coding RNAs (lncRNAs), a comprehensive analysis of RNA-sequencing and DNA methylation data of 1,200 clinical samples was performed. Differentially expressed lncRNAs (DELs) and survival-related lncRNAs in BC were identified using the R package. The function of the lncRNA was evaluated using Kaplan-Meier and receiver operating characteristic (ROC) curve analyses. The expression of the key lncRNA in tissues and cells was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Biological functions of the key lncRNA were analyzed using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses. The Connectivity Map (CMap) was used to search for small-molecule targeted drugs for the key lncRNA. The functions of the key lncRNA in BC progression were investigated using cell proliferation and cell cycle assays. Results: A total of 14 methylation-driven lncRNAs, 526 DELs, and 93 survival-associated lncRNAs were identified. The above data were intersected, and a unique lncRNA, LINC00092, was obtained. LINC00092 was hypermethylated and hypoexpressed in both BC tissues and cell lines. LINC00092 was found to be a diagnostic marker for BC, with its low expression being associated with poor prognosis (P=0.013). LINC00092 overexpression inhibited the proliferation and cell cycle of BC cells in vitro. Nimesulide and sulpiride were screened out as potential targeted therapeutic drugs for LINC00092 in BC, and sulpiride was observed to partially reverse the proliferative effect of (small interfer) si-LINC00092 on BC cells. Conclusions: LINC00092 is a methylation-driven lncRNA in BC and could be a potential therapeutic target for this disease.

Identification of a Five-miRNA Signature for Diagnosis of Kidney Renal Clear Cell Carcinoma.

Motivation: Kidney renal clear cell carcinoma, which is a common type and accounts for 70-80% of renal cell carcinoma, can easily lead to metastasis and even death. A reliable signature for diagnosis of this cancer is in need. Hence, we seek to select miRNAs for identifying kidney renal clear cell carcinoma. Method: A feature selection strategy is used and improved to identify microRNAs for diagnosis of kidney renal clear cell carcinoma. Samples representing kidney renal clear cell carcinoma and normal tissues are split into training and testing groups. Accumulated scores representing the variable importance of each miRNA are derived from an iteration of resampling, training, and scoring. Those miRNAs with higher scores are selected based on the Gaussian mixture model. The sample split is repeated ten times to get more central miRNAs. Results: A total of 611 samples are downloaded from TCGA, each of which contains 1,343 miRNAs. The improved feature selection method is implemented, and five miRNAs are identified as a biomarker for diagnosis of kidney renal clear cell carcinoma. GSE151419 and GSE151423 are selected as the independent testing sets. Experimental results indicate the effectiveness of the selected signature. Both data-driven measurements and knowledge-driven evidence are given to show the effectiveness of our selection results.

Tumor-associated macrophage-derived exosomes transmitting miR-193a-5p promote the progression of renal cell carcinoma via TIMP2-dependent vasculogenic mimicry.

Previous studies have investigated whether tumor-associated macrophages (TAMs) play tumorigenic and immunosuppressive roles to encourage cancer development, but the role of TAMs in regulating vasculogenic mimicry (VM) in clear-cell renal cell carcinoma (ccRCC) cells has not been completely clarified. We conducted immunostaining of the tumor-associated macrophage biomarkers CD68/CD163 and double staining for PAS/CD31 in ccRCC human specimens to find that higher TAM infiltration was positively correlated with VM formation. Then we demonstrated that TAM-derived exosomes downregulate TIMP2 expression in RCC cells to promote VM and invasion by shuttling miR-193a-5p. Mechanistic analysis indicated that HIF-1α upregulation in macrophages could transcriptionally increase miR-193a-5p expression. Exosome-shuttled miR-193a-5p then targeted the 3' untranslated region (UTR) of TIMP2 mRNA to suppress its translation. A preclinical study using an in vivo orthotopic xenograft model of ccRCC in mice substantiated that TAM-derived exosomes enhance VM and enable tumor progression, which confirmed our in vitro data. Suppressing TAM-derived exosomal miR-193a-5p successfully inhibited tumor progression and metastasis. Overall, miR-193a-5p from TAM-derived exosomes downregulates the TIMP2 gene to facilitate the development of RCC, which provides a novel perspective for developing therapeutic strategies for RCC.

High-dose-androgen-induced autophagic cell death to suppress the Enzalutamide-resistant prostate cancer growth via altering the circRNA-BCL2/miRNA-198/AMBRA1 signaling.

Androgen deprivation therapy (ADT) is a gold standard treatment for advanced PCa. However, most patients eventually develop the castration-resistant prostate cancer (CRPC) that progresses rapidly despite ongoing systemic androgen deprivation. While early studies indicated that high physiological doses of androgens might suppress rather than promote PCa cell growth in some selective CRPC patients, the exact mechanism of this opposite effect remains unclear. Here we found that Enzalutamide-resistant (EnzR) CRPC cells can be suppressed by the high-dose-androgen (dihydrotestosterone, DHT). Mechanism dissection suggested that a high-dose-DHT can suppress the circular RNA-BCL2 (circRNA-BCL2) expression via transcriptional regulation of its host gene BCL2. The suppressed circRNA-BCL2 can then alter the expression of miRNA-198 to modulate the AMBRA1 expression via direct binding to the 3'UTR of AMBRA1 mRNA. The consequences of high-dose-DHT suppressed circRNA-BCL2/miRNA-198/AMBRA1 signaling likely result in induction of the autophagic cell death to suppress the EnzR CRPC cell growth. Preclinical studies using in vivo xenograft mouse models also demonstrated that AMBRA1-shRNA to suppress the autophagic cell death can weaken the effect of high-dose-DHT on EnzR CRPC tumors. Together, these in vitro and in vivo data provide new insights for understanding the mechanisms underlying high-dose-DHT suppression of the EnzR CRPC cell growth, supporting a potential therapy using high-dose-androgens to suppress CRPC progression in the future.

Hypoxia increases RCC stem cell phenotype via altering the androgen receptor (AR)-lncTCFL5-2-YBX1-SOX2 signaling axis.

BACKGROUND: Early studies indicated that the androgen receptor (AR) could promote renal cell carcinoma (RCC) development and metastasis, but its linkage to RCC progression under hypoxia, remains unclear. RESULTS: Here we found AR expression in RCC cells decreased in response to hypoxia, which might then lead to increase the cancer stem cells (CSC) phenotype through the lncTCFL5-2-modulated YBX1/SOX2 signals. The consequences of such hypoxia-modulated AR/lncTCFL5-2/YBX1/SOX2 signals ablity to alter the CSC phenotype might render RCC cells more resistant to targeted therapy with Sunitinib. Mechanism dissection revealed that AR might alter the lncTCFL5-2/YBX1/SOX2 signaling through transcriptional suppression of the lncTCFL5-2 expression via the AR-response-elements (AREs) on the lncTCFL5-2 promoter. The lncTCFL5-2 interacts with YBX1 to increase its stability, which in turn increases SOX2 expression at a transcriptional level via the YBX1-response-elements (YBX1Es) on the SOX2 promoter. The in vivo mouse model with orthotopic xenografts of RCC cells also validates the in vitro data, and a human RCC sample survey demonstrated the clinical significance of the AR/lncTCFL5-2/YBX1/SOX2 signaling axis for the RCC prognosis, likely as a result of regulating CSC phenotypes. CONCLUSIONS: Together, these findings suggest that hypoxia may increase the RCC CSC phenotype via altering the AR/lncTCFL5-2/YBX1/SOX2 signaling axis and a potential therapy to target this newly identified signal perhaps may help improve the targeted therapy with Sunitinib to better suppress RCC progression.

High dose androgen suppresses natural killer cytotoxicity of castration-resistant prostate cancer cells via altering AR/circFKBP5/miRNA-513a-5p/PD-L1 signals.

Most advanced prostate cancer (PCa) patients initially respond well to androgen deprivation therapy, but almost all eventually develop castration-resistant prostate cancer (CRPC). Early studies indicated the bipolar androgen therapy via a cycling of high dose and low dose of androgen to suppress PCa growth might be effective in a select patient population. The detailed mechanisms, however, remain unclear. Here we found the capacity of natural killer (NK) cells to suppress the CRPC cells could be suppressed by a high dose of dihydrotestosterone (DHT). Mechanism dissection indicates that transactivated AR can increase circularRNA-FKBP5 (circFKBP5) expression, which could sponge/inhibit miR-513a-5p that suppresses the PD-L1 expression via direct binding to its 3'UTR to negatively impact immune surveillance from NK cells. Preclinical data from in vitro cell lines and an in vivo mouse model indicate that targeting PD-L1 with sh-RNA or anti-PD-L1 antibody can enhance the high dose DHT effect to better suppress CRPC cell growth. These findings may help us to develop novel therapies via combination of high dose androgen with PD-1/PD-L1 checkpoint inhibitors to better suppress CRPC progression.

Targeting the androgen receptor to enhance NK cell killing efficacy in bladder cancer by modulating ADAR2/circ_0001005/PD-L1 signaling.

Although androgen receptor (AR) can influence bladder cancer (BCa) initiation and progression, its impact on tumor immune escape remains unclear. Here, we found that targeting AR could enhance natural killer (NK) cell tumor-killing efficacy by decreasing PD-L1 expression. Both antiandrogen treatment and AR knockdown effectively reduced membrane PD-LI expression to facilitate NK cell-mediated BCa cell killing by downregulating circ_0001005. Mechanistically, AR upregulated circRNA circ_0001005 expression via the RNA-editing gene ADAR2. circ_0001005 competitively sponged the miRNA miR-200a-3p to promote PD-L1 expression. A preclinical BCa xenograft mouse model further confirmed this newly identified signaling using the small molecule circ_0001005-shRNA to improve NK cell killing of BCa tumor cells. Collectively, these results suggest that targeting the newly identified ADAR2/circ_0001005/miR-200a-3p/PD-L1 pathway to impact antitumor immunity may suppress progression and boost immunotherapeutic efficacy in BCa.

Targeting the radiation-induced ARv7-mediated circNHS/miR-512-5p/XRCC5 signaling with Quercetin increases prostate cancer radiosensitivity.

BACKGROUND: Radiation therapy (RT) with androgen deprivation therapy (ADT) is an effective therapy to suppress the locally advanced prostate cancer (PCa). However, we unexpectedly found that RT could also induce the androgen receptor splice variant 7 (ARv7) expression to decrease the radiosensitivity. METHODS: The study was designed to target ARv7 expression with Quercetin or ARv7-shRNA that leads to enhancing and increasing the radiation sensitivity to better suppress the PCa that involved the modulation of the circNHS/miR-512-5p/XRCC5 signaling. RESULTS: Mechanism studies revealed that RT-induced ARv7 may function via altering the circNHS/miR-512-5p/XRCC5 signaling to decrease the radiosensitivity. Results from preclinical studies using multiple in vitro cell lines and in vivo mouse models concluded that combining RT with the small molecule of Quercetin to target full-length AR and ARv7 could lead to better efficacy to suppress PCa progression. CONCLUSION: Together, these results suggest that ARv7 may play key roles to alter the PCa radiosensitivity, and targeting this newly identified ARv7 mediated circNHS/miR-512-5p/XRCC5 signaling with Quercetin may help physicians to develop a novel RT to better suppress the progression of PCa.

5-FU@DHA-UIO-66-NH2 potentiates chemotherapy sensitivity of breast cancer cells through a microRNA let-7a-dependent mechanism.

BACKGROUND: Drug delivery systems with magnetization facilitate the accumulation of drug at the target site. This study aimed to explore the mechanism by which docosahexaenoic acid (DHA)-modified porous metal-organic framework (MOF) UIO-66-NH2 loads chemotherapeutic drug 5-fluorouracil (5-FU) and reduces the chemotherapy resistance of breast cancer (BC) cells. METHODS: UIO-66-NH2 was synthesized and DHA with carboxyl end was used to modify the surface of UIO-66-NH2. 5-FU was incorporated to UIO-66-NH2 or DHA-UIO-66-NH2 by a post-synthesis method. The loading and release of 5-FU by @DHA-UIO-66-NH2 was investigated with ultraviolet (UV) spectroscopy. RT-qPCR was conducted to detect the expression of let-7a in cells. The uptake of DHA-UIO-66-NH2 by MCF-7 BC cells was observed by confocal laser scanning microscope (CLSM). Cell counting kit-8 (CCK-8), flow cytometry, and live/dead cell staining were applied to investigate the effects of 5-FU@DHA-UIO-66-NH2 on BC cells, and a BC mouse model was established to explore its effects on tumorigenesis. HE staining and routine blood index analysis were applied for determination of the biological safety of 5-FU@DHA-UIO-66-NH2. RESULTS: 5-FU@DHA-UIO-66-NH2 was successfully constructed and characterized. The loading amount of DHA-UIO-NH2 for 5-FU reached 30.31%. DHA-UIO-66-NH2 was effectively taken up by MCF-7 cells. Further, 5-FU@DHA-UIO-66-NH2 exhibited stronger inhibitory effects on MCF-7 cell viability in vitro as well as tumorigenesis in vivo than 5-FU and 5-FU@UIO-66-NH2. DHA up-regulated let-7a to reduce the resistance of MCF-7 cells to 5-FU. Moreover, the biosafety of 5-FU@DHA-UIO-66-NH2 was identified. CONCLUSIONS: 5-FU@DHA-UIO-66-NH2 increased the level of let-7a in BC cells, repressed cell viability and augmented apoptosis, and thus reduced the chemotherapy resistance of BC cells.

Intestinal dysbacteriosis leads to kidney stone disease.

The formation and physicochemical properties of kidney stones (KSs) are closely associated with diet. In view of the differences in ethnicity and dietary composition between Chinese and Western populations, the present study aimed to investigate the association between intestinal dysbacteriosis and KSs in China. The current study examined the differences in intestinal microbes between the KS disease (KSD) and the healthy control (HLT) groups, and statistically significant differences based on 16s rRNA gene amplicons were identified using a Student's t­test or one­way ANOVA. In addition, the calcium oxalate KS (COKS), uric acid KS (UAKS) and carbonate apatite KS(CCKS) groups were compared with a non­parametric statistical test. Determination of bacterial abundance was performed via the analysis of 16s rRNA marker gene sequences using next­generation sequencing. Firmicutes (F) and Bacteroides (B) levels were significantly higher in the KSD group compared with the HLT group (B/F=0.67 vs. 0.08; P<0.001), as were the overall levels of B (6.19­fold higher compared with the HLT group; 22.2 vs. 3.6%; P<0.001). The Prevotella­9 abundance levels in the KSD group were 4.65­fold higher compared with those in the HLT group (8.8 vs. 1.9%; P<0.001). The levels of Blautia and Lachnoclostridium were significantly decreased in the KSD group (13.3 vs. 6.0%; and 5.0 vs. 7.9%; both P<0.05). Moreover, Prevotella­9 levels were higher in non­calciferous KSs (UAKS) compared with calciferous KSs (COKS and CCKS). Therefore, the findings of the present study indicated a key association between specific KS components and intestinal flora, providing a theoretical basis for new treatment methods for KSs. Moreover, differences and interactions between these bacteria could initially predict specific types of urolithiasis.

ASC-J9® suppresses prostate cancer cell proliferation and invasion via altering the ATF3-PTK2 signaling.

BACKGROUND: Early studies indicated that ASC-J9®, an androgen receptor (AR) degradation enhancer, could suppress the prostate cancer (PCa) progression. Here we found ASC-J9® could also suppress the PCa progression via an AR-independent mechanism, which might involve modulating the tumor suppressor ATF3 expression. METHODS: The lentiviral system was used to modify gene expression in C4-2, CWR22Rv1 and PC-3 cells. Western blot and Immunohistochemistry were used to detect protein expression. MTT and Transwell assays were used to test the proliferation and invasion ability. RESULTS: ASC-J9® can suppress PCa cell proliferation and invasion in both PCa C4-2 and CWR22Rv1 cells via altering the ATF3 expression. Further mechanistic studies reveal that ASC-J9® can increase the ATF3 expression via decreasing Glutamate-cysteine ligase catalytic (GCLC) subunit expression, which can then lead to decrease the PTK2 expression. Human clinical studies further linked the ATF3 expression to the PCa progression. Preclinical studies using in vivo mouse model also proved ASC-J9® could suppress AR-independent PCa cell invasion, which could be reversed after suppressing ATF3. CONCLUSIONS: ASC-J9® can function via altering ATF3/PTK2 signaling to suppress the PCa progression in an AR-independent manner.

Suppressing BCL-XL increased the high dose androgens therapeutic effect to better induce the Enzalutamide-resistant prostate cancer autophagic cell death.

Most patients with advanced prostate cancer (PCa) initially respond well to androgen deprivation therapy (ADT) with antiandrogens, but most of them eventually become resistant to ADT. Here, we found that the antiandrogen Enzalutamide-resistant (EnzR) PCa cells can be suppressed by hyper-physiological doses of the androgen DHT. Mechanism dissection indicates that while androgens/androgen receptor (AR) can decrease BCL-2 expression to induce cell death, yet they can also simultaneously increase anti-apoptosis BCL-XL protein expression via decreasing its potential E3 ubiquitin ligase, PARK2, through transcriptionally increasing the miR-493-3p expression to target PARK2. Thus, targeting the high dose DHT/AR/miR-493-3p/PARK2/BCL-XL signaling with BCL-XL-shRNA can increase high-dose-DHT effect to better suppress EnzR cell growth via increasing the autophagic cell death. A preclinical study using in vivo mouse model also validated that suppressing BCL-XL led to enhance high dose DHT effect to induce PCa cell death. The success of human clinical trials in the future may help us to develop a novel therapy using high dose androgens to better suppress CRPC progression.

Targeting androgen receptor (AR) with antiandrogen Enzalutamide increases prostate cancer cell invasion yet decreases bladder cancer cell invasion via differentially altering the AR/circRNA-ARC1/miR-125b-2-3p or miR-4736/PPARγ/MMP-9 signals.

Androgen-deprivation therapy (ADT) via targeting androgens/androgen receptor (AR) signals may suppress cell proliferation in both prostate cancer (PCa) and bladder cancer (BCa), yet its impact on the cell invasion of these two urological cancers remains unclear. Here we found targeting androgens/AR with either the recently developed antiandrogen Enzalutamide (Enz) or AR-shRNAs led to increase PCa cell invasion, yet decrease BCa cell invasion. Mechanistic dissection revealed that suppressing androgens/AR signals could result in differential alterations of the selective circular RNAs (circRNAs) as a result of differential endogenous AR transcription. A negative autoregulation in PCa, yet a positive autoregulation in BCa, as a result of differential binding of AR to different androgen-response elements (AREs) and a discriminating histone H3K4 methylation, likely contributes to this outcome between these two urological tumors. Further mechanistic studies indicated that AR-encoded circRNA-ARC1 might sponge/alter the availability of the miRNAs miR-125b-2-3p and/or miR-4736, to impact the metastasis-related PPARγ/MMP-9 signals to alter the PCa vs. BCa cell invasion. The preclinical study using the in vivo mouse model confirms in vitro cell lines data, showing that Enz treatment could increase PCa metastasis, which can be suppressed after suppressing circRNA-ARC1 with sh-circRNA-ARC1. Together, these in vitro/in vivo results demonstrate that antiandrogen therapy with Enz via targeting AR may lead to either increase PCa cell invasion or decrease BCa cell invasion. Targeting these newly identified AR/circRNA-ARC1/miR-125b-2-3p and/or miR-4736/PPARγ/MMP-9 signals may help in the development of new therapies to better suppress the Enz-altered PCa vs. BCa metastasis.

Androgen receptor promotes renal cell carcinoma (RCC) vasculogenic mimicry (VM) via altering TWIST1 nonsense-mediated decay through lncRNA-TANAR.

While the androgen receptor (AR) may influence the progression of clear cell renal cell carcinoma (ccRCC), its role to impact vasculogenic mimicry (VM) to alter the ccRCC progression and metastasis remains obscure. Here, we demonstrated that elevated AR expression was positively correlated with tumor-originated vasculogenesis in ccRCC patients. Consistently, in vitro research revealed AR promoted VM formation in ccRCC cell lines via modulating lncRNA-TANAR/TWIST1 signals. Mechanism dissection showed that AR could increase lncRNA-TANAR (TANAR) expression through binding to the androgen response elements (AREs) located in its promoter region. Moreover, we found that TANAR could impede nonsense-mediated mRNA decay (NMD) of TWIST1 mRNA by direct interaction with TWIST1 5'UTR. A preclinical study using in vivo mouse model with orthotopic xenografts of ccRCC cells further confirmed the in vitro data. Together, these results illustrated that AR-mediated TANAR signals might play a crucial role in ccRCC VM formation and metastasis, and targeting this newly identified AR/TANAR/TWIST1 signaling may help in the development of a novel anti-angiogenesis therapy to better suppress the ccRCC progression.

Preclinical Study Using ABT263 to Increase Enzalutamide Sensitivity to Suppress Prostate Cancer Progression Via Targeting BCL2/ROS/USP26 Axis Through Altering ARv7 Protein Degradation.

BACKGROUND: The recently developed antiandrogen, Enzalutamide (Enz), has reformed the standard of care for castration resistant prostate cancer (CRPC) patients. However, Enz-resistance inevitably emerges despite success of Enz in prolonging CRPC patients' survival. Here we found that Enz-resistant prostate cancer (PCa) cells had higher BCL2 expression. We aimed to test whether targeting BCL2 would influence Enz sensitivity of prostate cancer (PCa) and identify the potential mechanism. METHODS: The study was designed to target Enz-induced BCL2 with inhibitor ABT263 and test Enz sensitivity in Enz-resistant PCa cells by MTT assay. Cellular reactive oxygen species (ROS) levels were detected with dihydroethidium staining, and in vitro deubiquitinating enzyme activity assay was used to evaluate ubiquitin specific protease 26 (USP26) activity. RESULTS: ABT263 could increase Enz sensitivity in both Enz-sensitive and Enz-resistant PCa cells via inducing ROS generation. Elevated cellular ROS levels might then inhibit USP26 activity to increase the ubiquitination of androgen receptor (AR) and AR splice variant 7 (ARv7) and their ubiquitin/proteasome-dependent degradation, which contributed to the increase of Enz sensitivity. In vivo mouse model also demonstrates that ABT263 will suppress the PCa progression. CONCLUSION: This study demonstrated that targeting Enz-induced BCL2 with inhibitor ABT263 could increase Enz sensitivity in both Enz-sensitive and Enz-resistant PCa cells through induction of cellular ROS levels and suppression of USP26 activity with a consequent increase of ubiquitin/proteasome-dependent degradation of AR and ARv7 protein expression.

Androgen receptor reverses the oncometabolite R-2-hydroxyglutarate-induced prostate cancer cell invasion via suppressing the circRNA-51217/miRNA-646/TGFß1/p-Smad2/3 signaling.

IDH1 (Isocitrate dehydrogenase 1) mutation occurring at codon 132 (R132) in prostate cancer (PCa) is considered as a classifier for a subgroup of PCas with accumulation of oncometabolite R-2HG (R-2-hydroxyglutarate). Here we found that adding R-2HG or the mutant IDH1 R132H could promote PCa cell invasion in androgen receptor (AR)-negative PC3 cells or suppressing the AR in AR-positive C4-2 cells. Mechanism dissection revealed that R-2HG could increase circRNA-51217 expression to sponge miRNA-646, which might then lead to increase TGFß1 expression and thus induce TGFß1/p-Smad2/3 signaling to increase PCa cell invasion. AR can suppress this R-2HG/circRNA-51217/miRNA-646/TGFß1/p-Smad2/3 signaling-increased PCa cell invasion via repressing TGFß1 transcription and inhibiting circRNA-51217 expression through regulating ADAR2 expression. Preclinical studies with an in vivo xenograft mouse model also revealed that PCa cells with the IDH1 R132H mutation have more invasive metastasis. This study demonstrates that IDH1 R132H mutation with increased oncometabolite R-2HG in PCa cells may play important roles to increase PCa cell invasion.