Poor Prognosis In Prostate Cancer Research Articles

Abstract 3070: Leveraging oxysterol sulfation by SULT2B1b sulfotransferase and liver X receptor inactivation to suppress advanced prostate cancer

Abstract Advanced prostate cancer is a heterogeneous disease driven by diverse genetic alterations, with metastasis and lethal progression as the inevitable outcome. We observed that a subset of clinical primary prostate cancer is markedly reduced for SULT2B1b (SULT2B) sulfotransferase, which is an oxysterol-sulfating enzyme. Metastasized castration-resistant prostate cancer (CRPC) uniformly lacks SULT2B. Oxysterols are oxidized cholesterol metabolites and in agonist function, they activate liver X receptors (LXRα/β), which are members of the nuclear receptor family and regulators of lipogenesis, cholesterol homeostasis and immune functions. LXR signaling is enzymatically inhibited by SULT2B activity since sulfated oxysterols are LXR-inert. We previously reported that genetic silencing of SULT2B led to escalated CRPC proliferation; enhanced xenograft tumor growth; increased cell migration, invasion; reduced stiffness, adhesiveness; and EMT activation. SULT2B-depleted CRPC cells showed robust upregulation of AKR1C3 aldo-keto reductase and AKR1C3-dependent activation of the ERK1/2 survival signal. AKR1C3 regulates intratumoral androgen biosynthesis, and it is known to be elevated in advanced prostate cancer. In the current study, we validate our previous result by showing that ectopic expression of SULT2B caused AKR1C3 reduction in CRPC cells. Mechanistically, we observed that enhanced AKR1C3 expression in SULT2B-depleted cells was prevented upon genetic or pharmacologic inactivation of LXR. In addition, ERRα, another non-steroid nuclear receptor, was reduced in LXR-inactivated cells and notably, AKR1C3 was reduced in CRPC cells upon ERRα degradation by an ERRα-selective PROTAC. The LXR dependence of ERRα and AKR1C3 expression was observed in both androgen receptor expressing and non-expressing CRPC cells. Conclusion & Translational Significance: Above results reveal a novel LXR-ERRα-AKR1C3-ERK axis which is activated in SULT2B-deficient CRPC cells irrespective of the androgen receptor status of these cells. Notably, elevated ERRα portends poor prognosis for prostate cancer and cholesterol is an ERRα agonist. Considering that statin can diminish ERRα activity (PMID 26777690) and AKR1C3 inhibitors are in clinical trials, this novel axis revealed from our study may be actionable for the clinical interception of the progression in SULT2B-low advanced prostate cancer. Citation Format: Bobae Park, Katarzyna Knapczyk-Stwora, Yaguang Liu, Chung S. Song, Bandana Chatterjee. Leveraging oxysterol sulfation by SULT2B1b sulfotransferase and liver X receptor inactivation to suppress advanced prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3070.

Abstract 1723: Ferroptosis is a novel therapeutic target for RB1 deficient lethal prostate cancer

Abstract Background: Although the development of next-generation antiandrogens has significantly extended the survival time of patients with metastatic castration-resistant prostate cancer (mCRPC), drug resistance inevitably developed over time. Therefore, the identification of novel therapeutic strategies targeting mCRPC is urgent. RB1 deficiency is a common genetic event and contributes to the development of therapy resistance and poor prognosis in prostate cancer. However, effective therapies against RB1-deficient lethal prostate cancer remain elusive. Here we determined how RB1 regulates the sensitivity of prostate cancer cells to ferroptosis, a form of regulated cell death driven by iron-dependent lipid peroxidation, and whether we can exploit ferroptosis for the treatment of RB1 deficient lethal prostate cancer. Methods: To determine how RB1 regulates ferroptosis in prostate cancer, we generated RB1 stable knockdown prostate cancer cell lines using lentivirus-delivered shRNAs. We compared cellular sensitivity to ferroptosis and associated lipid peroxidation between control and RB1 stable knockdown prostate cancer cells. Using western blotting, qPCR, and ChIP analyses, we examined the regulation of ferroptosis by RB1. We also evaluated the therapeutic efficacy of ferroptosis inducers in cell-derived xenograft, patient-derived xenograft, and genetically engineered mouse models. Results: Our studies revealed that RB1 deficiency sensitizes prostate cancer cells to ferroptosis. Mechanistically, we found that the E2F family of transcription factors directly binds and activates the ACSL4 promoter and that RB1 inhibits ferroptosis by suppressing E2F-mediated ACSL4 transcriptional activation. More importantly, our preclinical studies demonstrated that induction of ferroptosis by JKE-1674, a recently discovered ferroptosis inducer, significantly blocks RB1 deficient prostate tumor growth and metastasis, and improves the overall survival of mice in the absence of obvious toxicity. Conclusions: Our findings uncover an RB1/E2F/ACSL4 molecular axis that governs ferroptosis and also suggest a new approach to the treatment of RB1-deficient lethal prostate cancer. Citation Format: Mu-En Wang, Jiaqi Chen, Yi Lu, Jinjin Wy, Jianhong Ou, John Asara, Andrew Armstrong, Qianben Wang, Lei Li, Yuzhuo Wang, Jiaoti Huang, Ming Chen. Ferroptosis is a novel therapeutic target for RB1 deficient lethal prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1723.

Somatic and germline aberrations in homologous recombination repair genes in Chinese prostate cancer patients.

Somatic and germline aberrations in homologous recombinant repair (HHR) genes are associated with increased incidence and poor prognosis for prostate cancer. Through next-generation sequencing of prostate cancer patients across all clinical states from north China, here the authors identified a somatic mutational rate of 3% and a germline mutational rate of 3.9% for HRR genes using 200 tumor tissues and 714 blood specimens. Thus, mutational rates in HRR genes were lower compared with previous studies. Homologous recombination repair deficiency is associated with higher risk and poorer prognosis for prostate cancer. However, the landscapes of somatic and germline mutations in these genes remain poorly defined in Chinese patients, especially for those with localized disease and those from north part of China. In this study, we explore the genomic profiles of these patients. We performed next-generation sequencing with 200 tumor tissues and 714 blood samples from prostate cancer patients at Peking University First Hospital, using a 32 gene panel including 19 homologous recombination repair genes. TP53, PTEN, KRAS were the most common somatic aberrations; BRCA2, NBN, ATM were the most common germline aberrations. In terms of HRR genes, 3% (6/200) patients harbored somatic aberrations, and 3.8% (28/714) patients harbored germline aberrations. 98.0% (196/200) somatic-tested and 72.7% (519/714) germline tested patients underwent prostatectomy, of which 28.6% and 42.0% had Gleason scores ≥8 respectively. Gleason scores at either biopsy or prostatectomy were predictive for somatic aberrations in general and in TP53; while age of onset <60 years old, PSA at diagnosis, and Gleason scores at biopsy were clinical factors associated with positive germline aberrations in BRCA2/ATM. Our results showed a distinct genomic profile in homologous recombination repair genes for patients with prostate cancer across all clinical states from north China. Clinicians may consider to expand the prostate cancer patients receiving genetic tests to include more individuals due to the weak guiding role by the clinical factors currently available.

ARPC1A correlates with poor prognosis in prostate cancer and is up-regulated by glutamine metabolism to promote tumor cell migration, invasion and cytoskeletal changes

ObjectiveThis study aimed to identify potential biomarkers for prostate cancer (PCa) progression and metastasis, and to discern their biological functions.MethodsBioinformatics methods were used to screen for hub genes. The expression level of key hub genes in PCa was determined and their prognostic significance was examined. A series of functional assays were performed to investigate the function of the highest-ranking hub gene.ResultsActin related protein 2/3 complex subunit 1A (ARPC1A) was identified as the hub gene. ARPC1A was highly expressed in PCa tissues and cell lines, and was an independent prognostic factor for predicting biochemical recurrence after radical prostatectomy and overall survival of PCa patients. Knockdown of ARPC1A inhibited PCa cell migration, invasion and cytoskeleton formation, but had no impact on cell proliferation and cell cycle progression. In vivo, ARPC1A overexpression promoted lung metastasis of PCa, but had no efffect on tumor growth. Additionally, glutamine metabolism was identified as an upstream regulator of ARPC1A, and promoted migration, invasion and cytoskeletal changes of PCa cell through ARPC1A.ConclusionThese findings suggested that ARPC1A, which correlates with poor prognosis in PCa, functions downstream of glutamine metabolism to regulate cytoskeletal changes, cellular migration and cellular invasion in this disease.

GLIDR promotes the aggressiveness progression of prostate cancer cells by sponging miR-128–3p

Glioblastoma downregulated RNA (GLIDR) is a newly discovered long non-coding RNA (lncRNA) that its increased expression indicates a poor prognosis of prostate cancer (PCa). However, the effect of GLIDR on PCa cells is not clear. Our study investigated the role and molecular mechanism of GLIDR in PCa cells. The results showed that GLIDR expression levels were higher in PCa samples and cells than in control. GLIDR could regulate the invasive potential, epithelial-to-mesenchymal transition (EMT) and proliferation in PC-3 and LnCaP cells. Besides, GLIDR could weaken the inhibitory effects of miR-128-3p on invasion, EMT and proliferation in PCa cells. Western blotting proved that miR-128-3p affected the expression of EMT markers, such as E-cadherin, Snail and N-cadherin, and GLIDR could reversed the effects of miR-128-3p on the expression levels of EMT markers in PCa cells. In addition, knockdown of miR-128-3p stimulated the invasion, EMT, and proliferation in PCa cells, whereas these effects were reversed when GLIDR expression was knocked down. GLIDR knockdown inhibited the invasion, EMT, and proliferation in PCa cells, and GLIDR was shown to sponge miR-128-3p. Together, these results highlight GLIDR as a potential therapeutic target for the PCa treatment.

Tumor-infiltrating CD103+ cells define poor prognosis prostate cancer with favorable therapeutic response

Tumor-infiltrating CD103+ cells define poor prognosis prostate cancer with favorable therapeutic response

Novel, alternative splicing signature to detect lymph node metastasis in prostate adenocarcinoma with machine learning.

The presence of lymph node metastasis leads to a poor prognosis for prostate cancer (Pca). Recently, many studies have indicated that gene signatures may be able to predict the status of lymph nodes. The purpose of this study is to probe and validate a new tool to predict lymph node metastasis (LNM) based on alternative splicing (AS). Gene expression profiles and clinical information of prostate adenocarcinoma cohort were retrieved from The Cancer Genome Atlas (TCGA) database, and the corresponding RNA-seq splicing events profiles were obtained from the TCGA SpliceSeq. Limma package was used to identify the differentially expressed alternative splicing (DEAS) events between LNM and non-LNM groups. Eight machine learning classifiers were built to train with stratified five-fold cross-validation. SHAP values was used to explain the model. 333 differentially expressed alternative splicing (DEAS) events were identified. Using correlation filter and the least absolute shrinkage and selection operator (LASSO) method, a 96 AS signature was identified that had favorable discrimination in the training set and validated in the validation set. The linear discriminant analysis (LDA) was the best classifier after 100 iterations of training. The LDA classifier was able to distinguish between LNM and non-LNM with an area under the receiver operating curve of 0.962 ± 0.026 in the training set (D1 = 351) and 0.953 in the validation set (D2 = 62). The decision curve analysis plot proved the clinical application of the AS-based model. Machine learning combined with AS data could robustly distinguish between LNM and non-LNM in Pca.

Correlation of expression of Major Vault Protein with androgen receptor and immune checkpoint protein B7-H3, and with poor prognosis in prostate cancer.

Prostate cancer diagnosis and early stratification is an important aspect to avoid undertreatment of high-risk prostate cancer patients. Major Vault Protein (MVP) has been proposed as a prognostic biomarker in prostate cancer. PTEN and the immune checkpoint protein B7-H3 interact with MVP and are important in prostate cancer progression and therapy response. We evaluated the expression of MVP by immunohistochemistry of tissue microarray samples from a retrospective cohort consisting of 119 prostate cancer patients. We correlated the protein expression of MVP with clinicopathological characteristics, and protein expression of androgen receptor (AR), PTEN, immune checkpoint proteins B7-H3 and PD-L1. We found MVP to be expressed in 53% of prostate tumors, and correlated positively with biochemical recurrence (ρ=0.211/p=0.021). Furthermore, we found positive correlation of MVP expression with expression of AR (ρ=0.244/p=0.009) and the immune checkpoint protein B7-H3 (ρ=0.200/p=0.029), but not with PD-L1 (ρ=0.152/p=0.117) or PTEN expression (ρ=-0.034/p=0.721). Our findings support the notion that expression of MVP is associated with poor prognosis in prostate cancer. The correlation between MVP and immune checkpoint protein B7-H3 in prostate cancer suggests a role for MVP in immunoregulation and drug resistance.

Activation of the HNRNPA2B1/miR-93-5p/FRMD6 axis facilitates prostate cancer progression in an m6A-dependent manner.

It is becoming increasingly clear that N6-methyladenosine (m6A) plays a key role in post-transcriptional modification of eukaryotic RNAs in cancer. The regulatory mechanism of m6A modifications in prostate cancer is still not completely elucidated. Heterogeneous nuclear ribonucleoprotein A2/B1 (HNRNPA2B1), an m6A reader, has been revealed to function as an oncogenic RNA-binding protein. However, its contribution to prostate cancer progression remains poorly understood. Here, we found that HNRNPA2B1 was highly overexpressed and correlated with a poor prognosis in prostate cancer. In vitro and in vivo functional experiments demonstrated that HNRNPA2B1 knockout impaired proliferation and metastasis of prostate cancer. Mechanistic studies indicated that HNRNPA2B1 interacted with primary miRNA-93 and promoted its processing by recruiting DiGeorge syndrome critical region gene 8 (DGCR8), a key subunit of the Microprocessor complex, in an METTL3-dependent mechanism, while HNRNPA2B1 knockout significantly restored miR-93-5p levels. HNRNPA2B1/miR-93-5p downregulated FERM domain-containing protein 6 (FRMD6), a cancer suppressor, and enhanced proliferation and metastasis in prostate cancer. In conclusion, our findings identified a novel oncogenic axis, HNRNPA2B1/miR-93-5p/FRMD6, that stimulates prostate cancer progression via an m6A-dependent manner.

TRIM59 is suppressed by androgen receptor and acts to promote lineage plasticity and treatment-induced neuroendocrine differentiation in prostate cancer.

The incidence of treatment-induced neuroendocrine prostate cancer (t-NEPC) has been greatly increasing after the usage of secondgeneration androgen receptor (AR) pathway inhibitors (ARPIs). Neuroendocrine differentiation (NED) is closely associated with ARPI treatment failure and poor prognosis in prostate cancer (PCa) patients. However, the molecular mechanisms of NED are not fully understood. Here we report that upregulation of TRIM59, a TRIM family protein, is strongly correlated with ARPI treatment mediated NED and shorter patient survival in PCas. AR binds to TRIM59 promoter and represses its transcription. ARPI treatment leads to a reversal of repressive epigenetic modifications on TRIM59 gene and the transcriptional restraint on TRIM59 by AR. Upregulated TRIM59 then drives the NED of PCa by enhancing the degradation of RB1 and P53 and upregulating downstream lineage plasticity-promoting transcription factor SOX2. Altogether, TRIM59 is negatively regulated by AR and acts as a key driver for NED in PCas. Our study provides a novel prognostic marker for PCas and shed new light on the molecular pathogenesis of t-NEPC, a deadly variant of PCa.

SiAKR1C3@PPA complex nucleic acid nanoparticles inhibit castration-resistant prostate cancer in vitro.

AKR1C3, as a crucial androgenic enzyme, implicates the androgen biosynthesis and promoting prostate cancer cell growth in vitro. This study provides a new gene therapy strategy for targeting AKR1C3 to treat castration-resistant prostate cancer. siAKR1C3@PPA is assembled from PEG3500, PAMAM, Aptamer-PSMA, and siRNA for AKR1C3. We analyzed the relationship between AKR1C3 expression and the survival rate of prostate cancer patients based on the GEPIA online database to perform disease-free survival, and found that AKR1C3 may be an important factor leading to poor prognosis in prostate cancer. Considering AKR1C3 as a therapeutic target for castration-resistant prostate cancer, we constructed a complex nucleic acid nanoparticle, siAKR1C3@PPA to investigate the inhibitory effect on castration-resistant prostate cancer. Aptamer-PSMA acts as a target to guide siAKR1C3@PPA into PSMA-positive prostate cancer cells and specifically down regulate AKR1C3. Cyclin D1 was decreased as a result of siAKR1C3@PPA treatment. Changes in Cyclin D1 were consistent with decreased expression of AKR1C3 in LNCaP-AKR1C3 cells and 22RV1 cells. Furthermore, in the LNCaP-AKR1C3 group, 1070 proteins were upregulated and 1015 proteins were downregulated compared to the LNCaP group according to quantitative 4D label-free proteomics. We found 42 proteins involved in cell cycle regulation. In a validated experiment, we demonstrated that PCNP and CINP were up-regulated, and TERF2 and TP53 were down-regulated by western blotting. We concluded that siAKR1C3@PPA may arrest the cell cycle and affect cell proliferation.

MAPK8IP2 is a potential prognostic biomarker and promote tumor progression in prostate cancer

BackgroundMAPK8IP2 is one of the JNK-interacting proteins (JIPs) family members, and is involved in the regulation of the JNK and P38 MAPK signaling pathways. MAPK8IP2 has been reported to be closely associated with several cancers. However, the biological function of MAPK8IP2 in prostate cancer (PCa) remains unclear.MethodsMAPK8IP2 expression in PCa and subgroups of PCa was analyzed by public databases. The prognostic role of MAPK8IP2 in prostate cancer was analyzed using the Cox regression method. The potential mechanism by which MAPK8IP2 affects PCa progression was investigated by utilizing public data, including genetic alteration, DNA methylation, m6A methylation, and immune infiltration data. We further performed in vitro assays to validate the effect of MAPK8IP2 on PCa cell proliferation, migration and invasion.ResultsMAPK8IP2 is highly expressed in PCa tissues. Overexpression of MAPK8IP2 is associated with adverse clinicopathological factors and a poor prognosis in PCa. Receiver operating curve analysis showed that MAPK8IP2 can distinguish PCa tissues from non-PCa tissues with a certain accuracy (AUC = 0.814). The MAPK8IP2 genetic alteration rate was 2.6% and MAPK8IP2 alterations correlated with a poor prognosis. We also found that CDK12 and TP53 mutations were associated with MAPK8IP2 expression. The DNA methylation level of MAPK8IP2 was higher in primary tumors than in normal tissues, and the high MAPK8IP2 DNA methylation group of PCa patients had poor survival. Enrichment analysis indicated that MAPK8IP2 was involved in the MAPK signaling pathway. In vitro, knockdown of MAPK8IP2 inhibited PCa cell proliferation, migration and invasion.ConclusionMAPK8IP2 is a potential target for PCa treatment and can serve as a novel biomarker for PCa diagnosis and prognosis evaluation.

121P ATM germline mutations in lethal prostate cancer

Germline mutations in the ataxia telangiectasia mutated (ATM) gene occur in 0.5-1% of the overall population and are associated with tumour predisposition. The clinical and pathologic features of ATM-mutated prostate cancer (PC) have not been well defined. Data suggest that they are associated with poor prognosis PC. Herein, we examine our cohort of sequenced mCRPC for germline ATM mutations in patients with advanced PC, and report on associated clinical features.

Polymorphic variants of the CASP3, CASP9, BCL-2 and NKX3-1 genes as candidate markers for prostate cancer susceptibility and poor prognosis.

There is an ongoing search for molecular markers that are specific, sensitive, and able to predict the stage of prostate cancer (PCa), which is the second most prevalent type of cancer in men worldwide. This study examined whether different single nucleotide polymorphisms (SNPs) were reliable markers of susceptibility to and prognosis of PCa in a sample of Brazilian patients. DNA samples were extracted from peripheral blood cells of 283 PCa patients and matched with samples from healthy controls. Single nucleotide polymorphisms (SNPs in four genes (BCL-2-rs2279115, CASP3-rs4647603, CASP9-rs1052571, and NKX3-1-rs11781886) were genotyped by real-time PCR using the TaqMan® probe. Odds Ratios with 95% confidence intervals were calculated for allelic and genotypic frequencies. The association between polymorphic variants, risk of developing PCa, and clinicopathological characteristics was analyzed by univariate and multivariate logistic regression analysis. SNPs in CASP3, CASP9, and NKX3-1 genes, either alone or in combination (BCL-2+NKX3-1 and CASP3+NKX3-1) were associated with the risk of developing PCa. Genotypes and tumor histopathological data indicated that the BCL-2, NKX3-1, and CASP3 allelic variants, either alone or combined in pairs, were associated with a poor prognosis of PCa. Genetic polymorphisms in CASP3, NKX3-1, and BCL-2 genes were associated with susceptibility to PCa. The SNPs in the three genes alone and the SNP in the BCL-2 gene combined with the other two genes were strongly associated with adverse outcomes in PCa patients and are promising candidates for molecular markers for PCa prognosis.

Environmental microcystin exposure triggers the poor prognosis of prostate cancer: Evidence from case-control, animal, and in vitro studies

Microcystin-leucine-arginine (MC-LR) is positively linked with multiple cancers in humans. However, the association between MC-LR and the risk and prognosis of prostate cancer has not been conducted in epidemiological studies. No reported studies have linked MC-LR exposure to the poor prognosis of prostate cancer by conducting experimental studies. The content of MC-LR was detected in most of the aquatic food in wet markets and supermarkets in Nanjing and posed a health risk for consumers. MC-LR levels in both prostate cancer tissues and serum were significantly higher than controls. The adjusted odds ratio (OR) for prostate cancer risk by serum MC-LR was 1.75 (95%CI: 1.21-2.52) in the whole subjects, and a positive correlation between MC-LR and advanced tumor stage was observed. Survival curve analysis indicated patients with higher MC-LR levels in tissues exhibited poorer overall survival. Human, animal, and cell studies confirmed that MC-LR exposure increases the expression of estrogen receptor-α (ERα) and promotes epithelial-mesenchymal transition (EMT) in prostate cancer. Moreover, MC-LR-induced decreased E-cadherin levels, increased vimentin levels, and increased migratory and invasive capacities of prostate cancer cells were markedly suppressed upon ERα knockdown. MC-LR-induced xenograft tumor growth and lung metastasis in BALB/c nude mice can be effectively alleviated with ERα knockdown. Our data demonstrated that MC-LR upregulated vimentin and downregulated E-cadherin through activating ERα, promoting migration and invasion of prostate cancer cells. Our findings highlight the role of MC-LR in prostate cancer, providing new perspectives to understand MC-LR-induced prostatic toxicity.

High Expression of PDLIM2 Predicts a Poor Prognosis in Prostate Cancer and Is Correlated with Epithelial-Mesenchymal Transition and Immune Cell Infiltration

Purpose To elucidate the clinical and prognostic role of PDZ and LIM domain protein (PDLIM) genes and the association to epithelial-mesenchymal transition (EMT) and immune cell infiltration in patients with prostate cancer (PRAD). Methods The data of RNA-seq, DNA methylation, and clinical features of PRAD patients were collected from The Cancer Genome Atlas (TCGA) database to define the prognostic value of PDLIM gene expression and the association with EMT and immune cell infiltration. A tissue microarray including 134 radical prostatectomy specimens was served as validation by immunohistochemistry (IHC) staining analysis. Results The mRNA levels of PDLIM1/2/3/4/6/7 were significantly downregulated, while PDLIM5 was upregulated in PRAD (P < 0.05). High expression of PDLIM2 mRNA suggests poor progression free interval in PRAD patients. DNA methylation of PDLIM2 was correlated with its mRNA expression level, and that the cg22973076 methylation site in PDLIM2 was associated with shorter PFI (P < 0.05) in PRAD. Single-sample gene-set enrichment and gene functional enrichment results showed that PDLIM2 was correlated with EMT and immune processes. Spearman's test showed a significant correlation with six reported EMT signatures and several EMT signature-related genes. Tumor microenvironment analysis revealed that the PDLIM2 mRNA expression was positively correlated with the immune score, stromal score, and various tumor infiltrating immune cells. Additionally, the results showed that patients in the high-PDLIM2 mRNA expression group may be more sensitive to immune checkpoint blockade therapy. Finally, IHC analysis further implicated the protein level of PDLIM2 was upregulated in PRAD and acts as a novel potential biomarker in predicting tumor progression. Conclusion Our study suggests that PDLIM family genes might be significantly correlated with oncogenesis and the progression of PRAD. PDLIM2 correlated with EMT and immune cell infiltration by acting as an oncogene in PRAD, which may serve as a potential prognostic biomarker for PRAD patients.

Heterogeneous Expression and Subcellular Localization of Pyruvate Dehydrogenase Complex in Prostate Cancer.

BackgroundPyruvate dehydrogenase (PDH) complex converts pyruvate into acetyl-CoA by pyruvate decarboxylation, which drives energy metabolism during cell growth, including prostate cancer (PCa) cell growth. The major catalytic subunit of PDH, PDHA1, is regulated by phosphorylation/dephosphorylation by pyruvate dehydrogenase kinases (PDKs) and pyruvate dehydrogenase phosphatases (PDPs). There are four kinases, PDK1, PDK2, PDK3 and PDK4, which can phosphorylate and inactivate PDH; and two phosphatases, PDP1 and PDP2, that dephosphorylate and activate PDH.MethodsWe have analyzed by immunohistochemistry the expression and clinicopathological correlations of PDHA1, PDP1, PDP2, PDK1, PDK2, PDK3, and PDK4, as well as of androgen receptor (AR), in a retrospective PCa cohort of patients. A total of 120 PCa samples of representative tumor areas from all patients were included in tissue microarray (TMA) blocks for analysis. In addition, we studied the subcellular localization of PDK2 and PDK3, and the effects of the PDK inhibitor dichloroacetate (DCA) in the growth, proliferation, and mitochondrial respiration of PCa cells.ResultsWe found heterogeneous expression of the PDH complex components in PCa tumors. PDHA1, PDP1, PDK1, PDK2, and PDK4 expression correlated positively with AR expression. A significant correlation of PDK2 immunostaining with biochemical recurrence and disease-free survival was revealed. In PCa tissue specimens, PDK2 displayed cytoplasmic and nuclear immunostaining, whereas PDK1, PDK3 and PDK4 showed mostly cytoplasmic staining. In cells, ectopically expressed PDK2 and PDK3 were mainly localized in mitochondria compartments. An increase in maximal mitochondrial respiration was observed in PCa cells upon PDK inhibition by DCA, in parallel with less proliferative capacity.ConclusionOur findings support the notion that expression of specific PDH complex components is related with AR signaling in PCa tumors. Furthermore, PDK2 expression associated with poor PCa prognosis. This highlights a potential for PDH complex components as targets for intervention in PCa.

Correlation of NTRK1 Downregulation with Low Levels of Tumor-Infiltrating Immune Cells and Poor Prognosis of Prostate Cancer Revealed by Gene Network Analysis.

Prostate cancer (PCa) is a life-threatening heterogeneous malignancy of the urinary tract. Due to the incidence of prostate cancer and the crucial need to elucidate its molecular mechanisms, we searched for possible prognosis impactful genes in PCa using bioinformatics analysis. A script in R language was used for the identification of Differentially Expressed Genes (DEGs) from the GSE69223 dataset. The gene ontology (GO) of the DEGs and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed. A protein–protein interaction (PPI) network was constructed using the STRING online database to identify hub genes. GEPIA and UALCAN databases were utilized for survival analysis and expression validation, and 990 DEGs (316 upregulated and 674 downregulated) were identified. The GO analysis was enriched mainly in the “collagen-containing extracellular matrix”, and the KEGG pathway analysis was enriched mainly in “focal adhesion”. The downregulation of neurotrophic receptor tyrosine kinase 1 (NTRK1) was associated with a poor prognosis of PCa and had a significant positive correlation with infiltrating levels of immune cells. We acquired a collection of pathways related to primary PCa, and our findings invite the further exploration of NTRK1 as a biomarker for early diagnosis and prognosis, and as a future potential molecular therapeutic target for PCa.

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.

GATA binding protein 5-mediated transcriptional activation of transmembrane protein 100 suppresses cell proliferation, migration and epithelial-to-mesenchymal transition in prostate cancer DU145 cells

ABSTRACT It has been reported that transmembrane protein 100 (TMEM100) acts as a tumor regulator in several types of cancers. However, whether the expression of TMEM100 is associated with the development and prognosis of prostate cancer (PCa) remains elusive. Therefore, the present study aimed to uncover the role of GATA binding protein 5 (GATA5)-mediated activation of TMEM100 in the proliferation, migration and epithelial-to-mesenchymal transition (EMT) of PCa cells. The expressions of TMEM100 and GATA5 in PCa patients were analyzed by the GEPIA database. The binding site of GATA5 and TMEM100 promoter was predicted by the JASPAR database. Expressions of TMEM100 and GATA5 in PCa cells were detected by qRT-PCR and Western blot analysis. Cell Counting Kit 8 and colony formation assays were performed to measure cell proliferation. In addition, cell migration, invasion and the expression of EMT-associated proteins were evaluated using wound healing, transwell assay and Western blotting assays, respectively. The bioinformatics analysis revealed that TMEM100 was downregulated in PCa and was associated with overall survival of PCa. In addition, TMEM10 overexpression attenuated cell proliferation, migration, invasion and EMT in PCa cells. The interaction between TMEM100 and GATA5 was verified using dual luciferase reporter and chromatin immunoprecipitation assays. Furthermore, the results showed that GATA5 was downregulated and GATA5 silencing reversed the inhibitory effects of TMEM10 on PCa cells. Overall, the current study suggested that the GATA5-mediated transcriptional activation of TMEM100 could affect the behavior of PCa cells and was associated with poor prognosis in PCa.