Suppresses Prostate Cancer Progression Research Articles

Retraction Note: Circular RNA ITCH suppressed prostate cancer progression by increasing HOXB13 expression via spongy miR-17-5p

Retraction Note: Circular RNA ITCH suppressed prostate cancer progression by increasing HOXB13 expression via spongy miR-17-5p

ELK3 destabilization by speckle-type POZ protein suppresses prostate cancer progression and docetaxel resistance.

Accumulating evidence demonstrates that the activity regulation of ELK3, a member of the E26 transformation-specific oncogene family, is critical to regulating cell proliferation, migration, and survival in human cancers. However, the molecular mechanisms of how ELK3 induces chemoresistance in prostate cancer (PCa) have not been elucidated. In this study, we found that SPOP and ELK3 are an interacting partner. The interaction between SPOP and ELK3 resulted in increased ELK3 ubiquitination and destruction, assisted by checkpoint kinase-mediated ELK3 phosphorylation. Notably, the modulation of SPOP-mediated ELK3 protein stability affected the c-Fos-induced cell proliferation and invasion of PCa cells. The clinical involvement of the SPOP-ELK3 axis in PCa development was confirmed by an immunohistochemical assay on 123 PCa tissues, with an inverse correlation between increased ELK3 and decreased SPOP being present in ~80% of the specimens. This observation was supported by immunohistochemistry analysis using a SPOP-mutant PCa specimen. Finally, docetaxel treatment induced cell death by activating checkpoint kinase- and SPOP-mediated ELK3 degradation, while SPOP-depleted or SPOP-mutated PCa cells showed cell death resistance. Notably, this observation was correlated with the protein levels of ELK3. Taken together, our study reveals the precise mechanism of SPOP-mediated degradation of ELK3 and provides evidence that SPOP mutations contribute to docetaxel resistance in PCa.

Auraptene Enhances AMP-Activated Protein Kinase Phosphorylation and Thereby Inhibits the Proliferation, Migration and Expression of Androgen Receptors and Prostate-Specific Antigens in Prostate Cancer Cells.

Citrus hassaku extract reportedly activates AMPK. Because this extract contains an abundance of auraptene, we investigated whether pure auraptene activates AMPK and inhibits proliferation using prostate cancer cell lines. Indeed, auraptene inhibited the proliferation and migration of LNCaP cells and induced phosphorylation of AMPK or its downstream ACC in LNCaP, PC3, and HEK-293 cells, but not in DU145 cells not expressing LKB1. In addition, the mTOR-S6K pathway, located downstream from activated AMPK, was also markedly suppressed by auraptene treatment. Importantly, it was shown that auraptene reduced androgen receptor (AR) and prostate-specific antigen (PSA) expressions at both the protein and the mRNA level. This auraptene-induced downregulation of PSA was partially but significantly reversed by treatment with AMPK siRNA or the AMPK inhibitor compound C, suggesting AMPK activation to, at least partially, be causative. Finally, in DU145 cells lacking the LKB1 gene, exogenously induced LKB1 expression restored AMPK phosphorylation by auraptene, indicating the essential role of LKB1. In summary, auraptene is a potent AMPK activator that acts by elevating the AMP/ATP ratio, thereby potentially suppressing prostate cancer progression, via at least three molecular mechanisms, including suppression of the mTOR-S6K pathway, reduced lipid synthesis, and AR downregulation caused by AMPK activation.

Nucleophosmin 1 cooperates with BRD4 to facilitate c-Myc transcription to promote prostate cancer progression

Nucleophosmin 1 (NPM1) is a multifunctional protein that promotes tumor progression in various cancers and is associated with a poor prognosis of prostate cancer (PCa). However, the mechanism by which NPM1 exerts its malignant potential in PCa remains elusive. Here, we showed that NPM1 is overexpressed in PCa cell lines and tissues and that the dysregulation of NPM1 promotes PCa proliferation. We also demonstrated that NPM1 transcriptionally upregulates c-Myc expression in PCa cells that is diminished by blockade of bromodomain-containing protein 4 (BRD4). Furthermore, we detected a correlation between NPM1 and c-Myc in patient PCa specimens. Mechanistically, NPM1 influences and cooperates with BRD4 to facilitate c-Myc transcription to promote PCa progression. In addition, JQ1, a bromodomain and extra-terminal domain (BET) inhibitor, in combination with NPM1 inhibition suppresses PCa progression in vitro and in vivo. These results indicate that NPM1 promotes PCa progression through a c-Myc -mediated pathway via BRD4, and blockade of the NPM1–c-Myc oncogenic pathway may be a therapeutic strategy for PCa.

Redox responsive polymeric nanoparticles enhance the efficacy of cyclin dependent kinase 7 inhibitor for enhanced treatment of prostate cancer

Traditional therapies such as surgery and endocrine therapy no longer meet the clinical needs in prostate cancer treatment, and more effective treatments are urgently required. Recent studies have reported that targeted inhibition of the transcription factor cyclin dependent kinase 7 (CDK7) could effectively suppress prostate cancer progression. However, the toxicity of CDK7 inhibitors such as THZ1 is the main limitation of the clinical application. In this work, we synthesized Cys8E (C8E) nanoparticles (NPs) loaded with THZ1 (C8E@THZ1), a novel GSH-targeting and stimuli-responsive nano-delivery platform, and investigated its anti-tumor potential and biosafety properties. In vitro, C8E@THZ1 potently inhibited the proliferation and promoted the apoptosis of prostate cancer cells. On tumor-bearing mice, C8E@THZ1 inhibited tumors by up to 85%, while the damage of THZ1 to liver function was effectively avoided. These results confirmed that inhibition of CDK7 can effectively block the progression of prostate cancer, and that Cys8E NPs is a highly prospective delivery platform to promote the clinical application of CDK7 inhibitors.

Tensin 1 regulated by hepatic leukemia factor represses the progression of prostate cancer.

Hepatic leukemia factor (HLF), a transcription factor, is dysregulated in many cancers. This study investigates the function of HLF in prostate cancer (PCa) and its relation to tensin 1 (TNS1). Clinical tissues were collected from 24 PCa patients. Duke University 145 (DU145) and PC3 cells overexpressing HLF were established. HLF signaling was downregulated in PCa tissues compared to adjacent tissues and in DU145 and PC3 cells compared to prostate epithelial cells RWPE-1 or prostate stromal cells (WPMY-1). PCa cell lines with overexpression of HLF had reduced proliferative, migratory, and invasive activity, increased apoptosis, and cell mitosis mostly in the G0/G1 phase. HLF induced the TNS1 transcription to activate the p53 pathway. Depletion of TNS1 reversed the anti-tumor effects of HLF on PCa cells and tumor growth and metastasis in vivo. In summary, our findings suggest that HLF suppressed PCa progression by upregulating TNS1 expression and inducing the p53 pathway activation, which might provide insights into novel strategies for combating PCa.

Metformin Overcomes the Consequences of NKX3.1 Loss to Suppress Prostate Cancer Progression

BackgroundThe antidiabetic drug metformin has known anticancer effects related to its antioxidant activity; however, its clinical benefit for prostate cancer (PCa) has thus far been inconclusive. Here, we investigate whether the efficacy of metformin in PCa is related to the expression status of NKX3.1, a prostate-specific homeobox gene that functions in mitochondria to protect the prostate from aberrant oxidative stress. ObjectiveTo investigate the relationship of NKX3.1 expression and metformin efficacy in PCa. Design, setting, and participantsFunctional studies were performed in vivo and in vitro in genetically engineered mouse models and human LNCaP cells, and organotypic cultures having normal or reduced/absent levels of NKX3.1. Correlative studies were performed using two independent retrospective tissue microarray cohorts of radical prostatectomies and a retrospective cohort of prostate biopsies from patients on active surveillance. InterventionMetformin was administered before or after the induction of oxidative stress by treatment with paraquat. Outcome measurements and statistical analysisFunctional endpoints included analyses of histopathology, tumorigenicity, and mitochondrial function. Correlative endpoints include Kaplan-Meier curves and Cox proportional hazard regression models. Results and limitationsMetformin reversed the adverse consequences of NKX3.1 deficiency following oxidative stress in vivo and in vitro, as evident by reduced tumorigenicity and restored mitochondrial function. Patients with low NKX3.1 expression showed a significant clinical benefit from taking metformin. ConclusionsMetformin can overcome the adverse consequences of NKX3.1 loss for PCa progression by protecting against oxidative stress and promoting normal mitochondrial function. These functional activities and clinical correlates were observed only with low NKX3.1 expression. Thus, the clinical benefit of metformin in PCa may depend on the status of NKX3.1 expression. Patient summaryProstate cancer patients with low NKX3.1 are likely to benefit most from metformin treatment to delay disease progression in a precision interception paradigm.

Aspartoacylase suppresses prostate cancer progression by blocking LYN activation

BackgroundGlobally, despite prostate cancer (PCa) representing second most prevalent malignancy in male, the precise molecular mechanisms implicated in its pathogenesis remain unclear. Consequently, elucidating the key molecular regulators that govern disease progression could substantially contribute to the establishment of novel therapeutic strategies, ultimately advancing the management of PCa.MethodsA total of 49 PCa tissues and 43 adjacent normal tissues were collected from January 2017 to December 2021 at Zhongnan Hospital of Wuhan University. The advanced transcriptomic methodologies were employed to identify differentially expressed mRNAs in PCa. The expression of aspartoacylase (ASPA) in PCa was thoroughly evaluated using quantitative real-time PCR and Western blotting techniques. To elucidate the inhibitory role of ASPA in PCa cell proliferation and metastasis, a comprehensive set of in vitro and in vivo assays were conducted, including orthotopic and tumor-bearing mouse models (n = 8 for each group). A combination of experimental approaches, such as Western blotting, luciferase assays, immunoprecipitation assays, mass spectrometry, glutathione S-transferase pull-down experiments, and rescue studies, were employed to investigate the underlying molecular mechanisms of ASPA’s action in PCa. The Student’s t-test was employed to assess the statistical significance between two distinct groups, while one-way analysis of variance was utilized for comparisons involving more than two groups. A two-sided P value of less than 0.05 was deemed to indicate statistical significance.ResultsASPA was identified as a novel inhibitor of PCa progression. The expression of ASPA was found to be significantly down-regulated in PCa tissue samples, and its decreased expression was independently associated with patients’ prognosis (HR = 0.60, 95% CI 0.40–0.92, P = 0.018). Our experiments demonstrated that modulation of ASPA activity, either through gain- or loss-of-function, led to the suppression or enhancement of PCa cell proliferation, migration, and invasion, respectively. The inhibitory role of ASPA in PCa was further confirmed using orthotopic and tumor-bearing mouse models. Mechanistically, ASPA was shown to directly interact with the LYN and inhibit the phosphorylation of LYN as well as its downstream targets, JNK1/2 and C-Jun, in both PCa cells and mouse models, in an enzyme-independent manner. Importantly, the inhibition of LYN activation by bafetinib abrogated the promoting effect of ASPA knockdown on PCa progression in both in vitro and in vivo models. Moreover, we observed an inverse relationship between ASPA expression and LYN activity in clinical PCa samples, suggesting a potential regulatory role of ASPA in modulating LYN signaling.ConclusionOur findings provide novel insights into the tumor-suppressive function of ASPA in PCa and highlight its potential as a prognostic biomarker and therapeutic target for the management of this malignancy.

Palmitoyl acyltransferase ZDHHC7 inhibits androgen receptor and suppresses prostate cancer.

The hormonal transcription factor androgen receptor (AR) is a master regulator of prostate cancer (PCa). Protein palmitoylation, which attaches a palmitate fatty acid to a substrate protein, is mediated by a class of 23 ZDHHC (Zinc-Finger DHHC motif)-family palmitoyltransferases. Although palmitoylation has been shown to modify many proteins and regulate diverse cellular processes, little is known about ZDHHC genes in cancer. Here we examined ZDHHC family gene expression in human tissue panels and identified ZDHHC7 as a PCa-relevant member. RNA-seq analyses of PCa cells with ZDHHC7 de-regulation revealed global alterations in androgen response and cell cycle pathways. Mechanistically, ZDHHC7 inhibits AR gene transcription and therefore reduces AR protein levels and abolishes AR signaling in PCa cells. Accordingly, ZDHHC7 depletion increased the oncogenic properties of PCa cells, whereas restoring ZDHHC7 is sufficient to suppress PCa cell proliferation and invasion in vitro and mitigate xenograft tumor growth in vivo. Lastly, we demonstrated that ZDHHC7 is downregulated in human PCa compared to benign-adjacent tissues, and its loss is associated with worse clinical outcomes. In summary, our study reveals a global role of ZDHHC7 in inhibiting androgen response and suppressing PCa progression and identifies ZDHHC7 loss as a biomarker for aggressive PCa and a target for therapeutic intervention.

Histone methyltransferase KMT2D promotes prostate cancer progression through paracrine IL-6 signaling.

Histone methyltransferase KMT2D plays a critical role as a human oncogene in prostate cancer (PCa). Dysregulated inflammatory responses and cytokine signaling are implicated in cancer progression. Furthermore, interleukin 6 (IL-6) is a pleiotropic cytokine that contributes to PCa progression; however, the association between KMT2D and IL-6 in PCa remains unclear. PCa cell proliferative potential, migratory potential, and apoptosis invitro were determined using cell counting kit-8 (CCK-8), EdU incorporation, wound healing, and apoptosis assays. Proliferation and migratory potential were impaired and apoptosis was induced in PCa cells cultured with the conditioned medium from KMT2D-depleted cells. Cytokine array analysis showed that IL-6 was the most affected cytokine in the conditioned media. KMT2D knockdown significantly downregulated the expression of IL-6 in PCa cells. What's more, proliferation and migration were also impaired and apoptosis was also induced by silencing IL-6R expression. Immunohistochemistry (IHC) and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) were performed to validate the positive correlation between KMT2D and IL-6 in PCa tissue samples. Chromatin immunoprecipitation (ChIP)-PCR demonstrated that KMT2D and H3K4me1 occupied IL-6 enhancer regions and therefore, directly regulated IL-6 expression. The present study revealed that the KMT2D knockdown suppressed prostate cancer progression through the downregulation of paracrine IL-6 signaling. These results suggest that KMT2D could be regarded as a potential new target for PCa therapy.

Circular RNA circARHGEF28 inhibited the progression of prostate cancer via the miR-671-5p/LGALS3BP/NF-κB axis.

Circular RNAs (circRNAs) play crucial roles in various biological processes, including prostate cancer (PCa). However, the precise roles and mechanism of circRNAs are complicated. Hence, we studied the function of a circRNA that might be involved in the progression of PCa. In this study, we found that circARHGEF28 was frequently downregulated in PCa tissues and cell lines. Furthermore, gain- and loss-of function experiments in vitro showed that circARHGEF28 inhibited proliferation, migration, and invasion of PCa. Additionally, circARHGEF28 suppressed PCa progression in vivo. Bioinformatics analysis and RNA pull-down and capture assay found that circARHGEF28 sponged miR-671-5p in PCa cells. Importantly, qRT-PCR and dual luciferase assays found that Lectin galactoside-binding soluble 3 binding protein (LGALS3BP) was downstream of miR-671-5p, and western blot analysis further confirmed that LGALS3BP negatively regulated the nuclear factor kappa-B (NF-κB) pathway. These results demonstrated that circARHGEF28 abolished the degradation of LGALS3BP by sponging miR-671-5p, thus blocking the activation of the NF-κB pathway. Our findings revealed that circARHGEF28/miR-671-5p/LGALS3BP/NF-κB may be an important axis that regulates PCa progression.

NRP1 promotes prostate cancer progression via modulating EGFR-dependent AKT pathway activation

Prostate cancer (PCa) is the most common malignant tumor with a high global incidence in males. The mechanism underlying PCa progression is still not clear. This study observed that NRP1 was highly expressed in PCa and associated with poor prognosis in PCa patients. Functionally, NRP1 depletion attenuated the proliferation and migration ability of PCa cells in vitro and in vivo, while NRP1 overexpression promoted PCa cell proliferation and migration. Moreover, it was observed that NRP1 depletion induced G1 phase arrest in PCa cells. Mechanistically, HIF1α is bound to the specific promoter region of NRP1, thereby regulating its transcriptional activation. Subsequently, NRP1 interacted with EGFR, leading to EGFR phosphorylation. This study also provided evidence that the b1/b2 domain of NRP1 was responsible for the interaction with the extracellular domain of EGFR. Moreover, EGFR mediated NRP1-induced activation of the AKT signaling pathway, which promoted the malignant progression of PCa. In addition, the administration of NRP1 inhibitor EG01377 significantly inactivated the EGFR/AKT signaling axis, thereby suppressing PCa progression. In conclusion, the findings from this study highlighted the molecular mechanism underlying NRP1 expression in PCa and provide a potential predictor and therapeutic target for clinical prognosis and treatment of PCa.

Stromal FOXF2 suppresses prostate cancer progression and metastasis by enhancing antitumor immunity

Cancer-associated fibroblasts (CAFs) mediate an immunosuppressive effect, but the underlying mechanism remains incompletely defined. Here we show that increasing prostatic stromal Foxf2 suppresses the growth and progression of both syngeneic and autochthonous mouse prostate cancer models in an immunocompetent context. Mechanistically, Foxf2 moderately attenuates the CAF phenotype and transcriptionally downregulates Cxcl5, which diminish the immunosuppressive myeloid cells and enhance T cell cytotoxicity. Increasing prostatic stromal Foxf2 sensitizes prostate cancer to the immune checkpoint blockade therapies. Augmenting lung stromal Foxf2 also mediates an immunosuppressive milieu and inhibits lung colonization of prostate cancer. FOXF2 is expressed higher in the stroma of human transition zone (TZ) than peripheral zone (PZ) prostate. The stromal FOXF2 expression level in primary prostate cancers inversely correlates with the Gleason grade. Our study establishes Foxf2 as a stromal transcription factor modulating the tumor immune microenvironment and potentially explains why cancers are relatively rare and indolent in the TZ prostate.

Effect of transmembrane protein 100 on prostate cancer progression by regulating SCNN1D through the FAK/PI3K/AKT pathway

The effects of transmembrane (TMEM) proteins in the progression of prostate cancer (PCa) remain unknown. This study aims to explore the functions of TMEM100 in PCa. To explore the expression, regulation, and effects of TMEM100 in PCa, two PCa cell lines and 30 PCa tissue samples with adjacent control tissues were examined. Online databases, immunohistochemistry, immunofluorescence, western blot, flow cytometry, colony formation, wound healing, transwell assays, and xenograft mouse models were used to explore effects of TMEM100 relevant to PCa. TMEM100 expression was shown to decrease in PCa patients, and low TMEM100 expression was associated with tumor stage and metastasis. Overexpression of TMEM100 suppressed PCa progression by inhibiting the FAK/PI3K/AKT signaling pathway. Tumor size was smaller in TMEM100 overexpressing PCa cells in xenograft mice than in control mice. We also found that TMEM100 could regulate SCNN1D by inhibiting FAK/PI3K/AKT signaling in PCa cell lines. Taken together, our findings indicate that TMEM100 is a tumor suppressor that plays a vital role in preventing PCa proliferation, migration, and invasion through inhibition of FAK/PI3K/AKT signaling. These studies suggest that TMEM100 can be used as a predictive biomarker and therapeutic target.

Long Non-Coding RNA AC008972.1 as a Novel Therapeutic Target for Prostate Cancer.

Background: Prostate cancer is a common male malignancy and the leading cause of cancer death in men. Long non-coding RNAs (lncRNAs), microRNA (miRNAs) and mRNAs networks mediate prostate cancer progression. Herein, we investigated the functions of lncRNA AC008972.1 and its regulatory mechanism in prostate cancer. Materials and Methods: The expression levels of lncRNA AC008972.1, miR-143-3p, and TAOK2 were detected in prostate cancer tissues and cell lines by reverse transcription-quantitative polymerase chain reaction. PC3 and LNCaP cells were used to establish lncRNA AC008972.1-knockdown, miR-143-3p-overexpressing, and thousand-and-one-amino acid 2 kinase (TAOK2)-downregulated cells. Cell viability was examined by MTT assays and cell proliferation was detected by clone formation assay. Cell migration and invasion were detected by wound scratch assay and transwell chamber assay. The apoptosis rate was analyzed by flow cytometry. The protein expression was detected by Western blot assay. The RNA interaction was explored and validated by RNA binding protein immunoprecipitation (RIP) assay and dual luciferase activity assay. A mouse xenograft model was established to investigate the effect of lncRNA AC008972.1 on prostate cancer progression. Results: High expression of lncRNA AC008972.1 was associated with low overall survival in prostate cancer patients. Downregulation of lncRNA AC008972.1 suppressed prostate cancer progression by inhibiting cell viability, proliferation, migration, and invasion, in addition to the EMT process, whereas cell apoptosis was significantly promoted. LncRNA AC008972.1 bound with miR-143-3p and negatively regulated miR-143-3p expression. MiR-143-3p overexpression suppressed prostate cancer malignant behaviors in vitro. TAOK2 expression was decreased by miR-143-3p through the complementary targeting of TAOK2 mRNA. Downregulation of lncRNA AC008972.1 mitigated prostate cancer malignant behaviors in vitro based on miR-143-3p/TAOK2 node. Furthermore, the data of xenograft model experiment showed that inhibition of lncRNA AC008972.1 suppressed tumor growth in vivo. Conclusions: Knockdown of lncRNA AC008972.1 inhibits prostate cancer cell growth via downregulation of TAOK2 induced by miR-143-3p. LncRNA AC008972.1 acts as an oncogene in the progression of prostate cancer and may provide a novel therapeutic target for prostate cancer.

N6-methyladenosine demethylase FTO suppressed prostate cancer progression by maintaining CLIC4 mRNA stability

The fat mass and obesity-associated protein (FTO) is an N6-Methyladenosine (m6A) demethylase, which has been revealed to play critical roles in tumorigenesis. However, its role in the development and progression of prostate cancer (PCa) remains poorly understood. Here, we aimed to investigate the function and clinical relevance of FTO in PCa. Our results demonstrated that FTO was notably downregulated in PCa tissues compared with the paired normal tissues. In addition, the decreased expression of FTO was correlated with poor prognosis of PCa. Functional experiments showed that depletion of FTO promoted the proliferation and metastasis of PCa both in vitro and in vivo. Conversely, ectopic expression of FTO exhibited the opposite effects. Combined with RNA-sequencing, MeRIP-RT-qPCR, and mRNA stability assays indicated chloride intracellular channel 4(CLIC4) was a functional target of FTO-mediated m6A modification. FTO depletion significantly increased the m6A level of CLIC4 mRNA and then reduced the mRNA stability. In conclusion, our findings suggest that FTO suppresses PCa proliferation and metastasis through reducing the degradation of CLIC4 mRNA in an m6A dependent manner. FTO may be used as a promising novel therapeutic target and prognostic evaluation biomarker for PCa.

MicroRNA-21 deficiency suppresses prostate cancer progression through downregulation of the IRS1-SREBP-1 signaling pathway.

Sterol regulatory element-binding protein 1 (SREBP-1), a master transcription factor in lipogenesis and lipid metabolism, is critical for disease progression and associated with poor outcomes in prostate cancer (PCa) patients. However, the mechanism of SREBP-1 regulation in PCa remains elusive. Here, we report that SREBP-1 is transcriptionally regulated by microRNA-21 (miR-21) in vitro in cultured cells and in vivo in mouse models. We observed aberrant upregulation of SREBP-1, fatty acid synthase (FASN) and acetyl-CoA carboxylase (ACC) in Pten/Trp53 double-null mouse embryonic fibroblasts (MEFs) and Pten/Trp53 double-null mutant mice. Strikingly, miR-21 loss significantly reduced cell proliferation and suppressed the prostate tumorigenesis of Pten/Trp53 mutant mice. Mechanistically, miR-21 inactivation decreased the levels of SREBP-1, FASN, and ACC in human PCa cells through downregulation of insulin receptor substrate 1 (IRS1)-mediated transcription and induction of cellular senescence. Conversely, miR-21 overexpression increased cell proliferation and migration; as well as the levels of IRS1, SREBP-1, FASN, and ACC in human PCa cells. Our findings reveal that miR-21 promotes PCa progression by activating the IRS1/SREBP-1 axis, and targeting miR-21/SREBP-1 signaling pathway can be a novel strategy for controlling PCa malignancy.

Targeting the Lnc-OPHN1-5/androgen receptor/hnRNPA1 complex increases Enzalutamide sensitivity to better suppress prostate cancer progression

Long non-coding RNAs (lncRNAs) have been found to play critical roles in regulating gene expression, but their function in translational control is poorly understood. We found lnc-OPHN1-5, which lies close to the androgen receptor (AR) gene on chromosome X, increased prostate cancer (PCa) Enzalutamide (Enz) sensitivity via decreasing AR protein expression and associated activity. Mechanism dissection revealed that lnc-OPHN1-5 interacted with AR-mRNA to minimize its interaction with the RNA binding protein (RBP) hnRNPA1. Suppressing lnc-OPHN1-5 expression promoted the interaction between AR-mRNA and hnRNPA1, followed by an increase of ribosome association with AR-mRNA and translation. This effect was reversed by increasing lnc-OPHN1-5 expression. Consistently, the in vivo mice model confirmed that knocking down lnc-OPHN1-5 expression in tumors significantly increased the tumor formation rate and AR protein expression compared with the control group. Furthermore, knocking down hnRNPA1 blocked/reversed shlnc-OPHN1-5-increased AR protein expression and re-sensitized cells to Enz treatment efficacy. Evidence from Enz-resistant cell lines, patient-derived xenograft (PDX) models, clinical samples, and a human PCa study accordantly suggested that patients with low expression of lnc-OPHN1-5 likely have unfavorable prognoses and probably are less sensitive to Enz treatment. In summary, targeting this newly identified lnc-OPHN1-5/AR/hnRNPA1 complex may help develop novel therapies to increase Enz treatment sensitivity for suppressing the PCa at an advanced stage.

CircLRP6 contributes to prostate cancer growth and metastasis by binding to miR-330-5p to up-regulate NRBP1

BackgroundCircular RNA low-density lipoprotein receptor-related protein 6 (circLRP6) is considered as an oncogene in many types of cancers. However, the function and mechanisms of circLRP6 in prostate cancer (PCa) tumorigenesis remain largely undefined.MethodsQuantitative real-time polymerase chain reaction (qRT-PCR) and western blot assays were conducted to assess the expression of circLRP6, microRNA (miR)-330-5p, and nuclear receptor binding protein 1 (NRBP1). Cell counting kit-8 (CCK-8), colony formation, 5-ethynyl-2’-deoxyuridine (EDU) incorporation, flow cytometry, transwell, wound healing, and western blot assays were performed to detect cell proliferation, apoptosis, and metastasis in vitro. Subcutaneous tumor growth was observed in nude mice to investigate the role of circLRP6 in vivo. The targeting relationship between miR-330-5p and NRBP1 or circLRP6 was verified using dual-luciferase reporter, pull-down, and RNA immunoprecipitation (RIP) assays. Immunohistochemistry was employed to test relative protein expression.ResultsCircLRP6 was highly expressed in PCa tissues and cells, knockdown of circLRP6 impaired PCa cell growth and metastasis in vitro by affecting cell proliferation, apoptosis, invasion, migration, and epithelial-mesenchymal transition (EMT). Mechanistic studies showed that circLRP6 could competitively bind with miR-330-5p to prevent the degradation of its target gene NRBP1. Rescue assay suggested that miR-330-5p inhibition reversed the inhibitory effects of circLRP6 knockdown on PCa cell growth and metastasis. Moreover, overexpression of miR-330-5p suppressed PCa progression via NRBP1. Notably, tumor formation assay indicated that circLRP6 silencing impeded tumor growth and EMT in vivo.ConclusionOur findings demonstrated that circLRP6 promoted PCa tumorigenesis and metastasis through miR-330-5p/NRBP1 axis, suggesting a potential therapeutic target for PCa.

A phase II randomized controlled trial of exercise on biochemical progression in men with prostate cancer on active surveillance.

5080 Background: Men with prostate cancer (PCa) undergoing active surveillance (AS) are at increased risks of cardiovascular death and disease progression. Any intervention that can address these issues during AS would be highly beneficial. Clinical and preclinical studies have demonstrated the benefits of exercise to improve cardiovascular health in cancer patients and suggested the potential role of exercise in suppressing PCa progression in men with PCa undergoing AS. Therefore, the purpose of this study was to investigate the effects of exercise on cardiorespiratory fitness and biochemical progress of PCa in men with PCa on AS. Methods: The Exercise During Active Surveillance for Prostate Cancer (ERASE) Trial was a single-centre, two-armed, randomized controlled trial in Edmonton, Canada. 52 men with localized PCa who were undergoing AS were randomized to high-intensity interval training (HIIT; n = 26) or usual care (UC; n = 26). The HIIT group performed thrice-weekly, supervised, aerobic HIIT on a treadmill at 85-95% of peak cardiorespiratory fitness (VO2peak) for 12 weeks. The primary outcome was VO2peak, and the secondary and exploratory outcomes included biochemical progression of PCa (prostate-specific antigen [PSA]), PSA kinetics, and growth of prostate cancer cell line LNCaP. Results: 46/52 participants (88%) completed the postintervention VO2peak assessment and adherence to HIIT was 96%. Compared to UC, HIIT significantly improved VO2peak (adjusted between-group mean difference, 1.6 ml·kg-1·min-1; 95% confidence interval [CI], 0.3 to 2.9; p= 0.014). HIIT also significantly reduced PSA level (adjusted between-group mean difference, -1.1 ug/L; 95% CI, -2.1 to 0.0; p= 0.043) and PSA velocity ( p= 0.040), and suppressed LNCaP cell growth ( p =0.024). No significant differences were found in PSA doubling time ( p= 0.10) and testosterone ( p= 0.24). Conclusions: The ERASE Trial is the first randomized controlled trial to demonstrate the impact of HIIT exercise for improving physical fitness and inhibiting biochemical progression of PCa in men with localized PCa on AS. Our findings suggest that supervised aerobic HIIT may be a promising intervention in this clinical setting. Larger-scale randomized controlled trials are warranted to determine if improvements in physical fitness and PCa-related markers translate into improved long-term clinical outcomes in these men such as disease progression, receipt of radical treatments, posttreatment complications, and survival. Clinical trial information: NCT03203460.