Aggressive Prostate Cancer Cell Lines Research Articles

Abstract C097: PVT1 exon 9-dependent overexpression of RSAD2 is a characteristic of prostate cancer in males of African ancestry

Abstract Aggressive prostate cancer (PCa), including castrate-resistant and neuroendocrine subtypes, is projected to increase in incidence 5% each year. Aggressive PCa disproportionally impacts African American men, has limited effective treatment options and high mortality rates. Although racial disparities are established in PCa development, attributed to multiple contributory factors including systemic racism, differences in socioeconomic status and distrust in the medical system, work is still needed to understand the contribution of biological factors. We found the exon 9 region of plasmacytoma variant translocation 1 (PVT1) overexpressed in aggressive PCa cell lines derived from African American (AA) men. We found PVT1 exon 9 overexpression induced phenotypic changes to normal prostate epithelial cells in vitro and led to tumor formation in vivo. RNA-sequencing analysis revealed 156 significantly differentially expressed genes influenced by PVT1 exon 9 overexpression and radical S-adenosyl methionine domain containing 2 (RSAD2) was the top significantly overexpressed gene (log2Fold change 1.71, p-value < 0.05). We utilized the GSE223405 publicly available dataset to identify whether our identified PVT1 exon 9 downstream genes were enriched in AA prostate cancer cells. RSAD2 was significantly overexpressed in AA prostate cancer cells compared to prostate cancer cells from men of European ancestry (moEA) (log2Fold change 6.18, p-value < 0.05). Comparing normal cells to prostate cancer cells between these groups, we found that normal AA prostate cells had significantly higher expression of RSAD2 (log2fold change 4.25, p-value < 0.001) whereas moEA samples did not (log2fold change 0.837, p-value=0.150). From analysis of data obtained from cBioPortal, we found RSAD2 alteration significantly correlates (p-value < 0.001) with self-identified race and copy number overexpression of RSAD2 was found to be enriched in AA patients (18.16% moEA versus 24% AA). Finally, we found 88.6% of the significantly differentially expressed genes within our PVT1 exon 9 RNA-sequencing dataset were significantly differentially expressed in GSE223405 AA samples and of those, 51.7% of genes exhibited a similar differential expression pattern suggesting that the PVT1 exon 9/RSAD2 dependent pathway may be more prominent in AA men. Mechanistically, we found two differing pathways of RSAD2 overexpression in aggressive prostate cancer cell models, one dependent and one independent of PVT1 exon 9 overexpression, with similar but differing biological functions related to epigenetic processes and metabolism. Ongoing work is investigating the RSAD2 and PVT1 exon 9 expression axis in a diverse set of human prostate cancer tissues and investigating their utilization as a therapeutic target in prostate cancer. Citation Format: Rachel E. Sexton-Bonacci1, Murtaza Barkarar1, Chindeum Udekwu1, Olorunseun O. Ogunwobi1. PVT1 exon 9-dependent overexpression of RSAD2 is a characteristic of prostate cancer in males of African ancestry [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C097.

The Differential Paracrine Role of the Endothelium in Prostate Cancer Cells.

Simple SummaryA growing body of literature supports the concept that a tumor mass is under the strict control of the microvascular endothelium and that the perfusion of oxygen and nutrients by capillary vessels to the tumor mass is reinforced by potent paracrine activity from the vascular endothelial cells. In our study, we investigate the biological and molecular implications of the paracrine crosstalk between vascular endothelial cells and prostate cancer cells. Our results indicate that the endothelial cells were able to secrete molecular signals that promote the proliferation and growth of low and highly aggressive prostate cancer cells and selectively increased the migration, invasion and metastatic potential of highly aggressive prostate cancer cells. The molecular analyses indicated that endothelial cells induced a differential effect on gene expression profile when comparing low versus highly aggressive prostate cancer cells, causing an enrichment of epigenetic changes in migratory pathways in highly aggressive prostate cancer cells. In conclusion, our results indicate that endothelial cells release signals that favor tumor growth and aggressiveness and that this interaction may play an important role in the progression of prostate cancer.The survival of patients with solid tumors, such as prostate cancer (PCa), has been limited and fleeting with anti-angiogenic therapies. It was previously thought that the mechanism by which the vasculature regulates tumor growth was driven by a passive movement of oxygen and nutrients to the tumor tissue. However, previous evidence suggests that endothelial cells have an alternative role in changing the behavior of tumor cells and contributing to cancer progression. Determining the impact of molecular signals/growth factors released by endothelial cells (ECs) on established PCa cell lines in vitro and in vivo could help to explain the mechanism by which ECs regulate tumor growth. Using cell-conditioned media collected from HUVEC (HUVEC-CM), our data show the stimulated proliferation of all the PCa cell lines tested. However, in more aggressive PCa cell lines, HUVEC-CM selectively promoted migration and invasion in vitro and in vivo. Using a PCa-cell-line-derived xenograft model co-injected with HUVEC or preincubated with HUVEC-CM, our results are consistent with the in vitro data, showing enhanced tumor growth, increased tumor microvasculature and promoted metastasis. Gene set enrichment analyses from RNA-Seq gene expression profiles showed that HUVEC-CM induced a differential effect on gene expression when comparing low versus highly aggressive PCa cell lines, demonstrating epigenetic and migratory pathway enrichments in highly aggressive PCa cells. In summary, paracrine stimulation by HUVEC increased PCa cell proliferation and tumor growth and selectively promoted migration and metastatic potential in more aggressive PCa cell lines.

Seleno-aspirin compound AS-10 promotes histone acetylation ahead of suppressing androgen receptor transcription, G1 arrest, and apoptosis of prostate cancer cells.

The novel selenium-aspirin compound AS-10 was recently reported by us with a cancer cell killing potency three orders of magnitude greater than aspirin in pancreatic cancer cell lines with caspase-mediated apoptosis and a reasonable selectivity against malignant cells. Although we also observed its cytocidal activity against PC-3 and DU145 androgen receptor (AR)-negative and P53-null/mutant aggressive human prostate cancer (PCa) cell lines in NCI-60 screen, the potential involvement and targeting of AR and P53 pathways that are intact in early-stage prostate carcinogenesis has not been examined, nor its primary molecular signaling after exposure. Human LNCaP PCa cells with functional AR and intact P53 were used to examine their cell cycle and cell fate responses to AS-10 exposure and upstream molecular signaling events including histone acetylation as a known aspirin effect. The AR-positive 22Rv1 human PCa cells were used to validate key findings. In addition to confirming AS-10's superior cytocidal potency than aspirin against all four PCa cell lines, we report a rapid (within 5 min) promotion of histone acetylation several hours ahead of the suppression of AR and prostate-specific antigen (PSA, coded by KLK3 gene) in LNCaP and 22Rv1 cells. AS-10 decreased AR and KLK3 mRNA levels without impacting pre-existing AR protein degradation or nuclear translocation in LNCaP cells. Sustained exposure to AS-10 arrested cells predominantly in G1 , and induced caspase-mediated apoptosis without necrosis. The death induced by AS-10 in LNCaP cells was attenuated by nontranscriptional activation of P53 protein or Jun N-terminal Kinase cellular stress signaling and was mitigated modestly by glutathione-boosting antioxidant N-acetylcysteine. AS-10 synergized with histone deacetylase inhibitor SAHA to suppress AR/PSA abundance and kill LNCaP cells. RNA-seq confirmed AR suppression at the transcriptional level and suggested multiple oncogene, cyclin, and CDK/CKI transcriptional actions to contribute to the cellular consequences. AS-10 promotes histone acetylation as its probable primary mechanism of action to induce PCa cell-cycle arrest and apoptosis, regardless of AR and P53 status. Nevertheless, the inhibition of AR signaling through mechanisms distinct from canonical AR antagonists may hold promise for combinatorial use with androgen deprivation therapy regimens or AR-axis targeting drugs.

Identification and Characterization of Key Differentially Expressed Genes Associated With Metronomic Dosing of Topotecan in Human Prostate Cancer.

Repetitive, low-dose (metronomic; METRO) drug administration of some anticancer agents can overcome drug resistance and increase drug efficacy in many cancers, but the mechanisms are not understood fully. Previously, we showed that METRO dosing of topotecan (TOPO) is more effective than conventional (CONV) dosing in aggressive human prostate cancer (PCa) cell lines and in mouse tumor xenograft models. To gain mechanistic insights into METRO-TOPO activity, in this study we determined the effect of METRO- and CONV-TOPO treatment in a panel of human PCa cell lines representing castration-sensitive/resistant, androgen receptor (+/−), and those of different ethnicity on cell growth and gene expression. Differentially expressed genes (DEGs) were identified for METRO-TOPO therapy and compared to a PCa patient cohort and The Cancer Genome Atlas (TCGA) database. The top five DEGs were SERPINB5, CDKN1A, TNF, FOS, and ANGPT1. Ingenuity Pathway Analysis predicted several upstream regulators and identified top molecular networks associated with METRO dosing, including tumor suppression, anti-proliferation, angiogenesis, invasion, metastasis, and inflammation. Further, the top DEGs were associated with increase survival of PCa patients (TCGA database), as well as ethnic differences in gene expression patterns in patients and cell lines representing African Americans (AA) and European Americans (EA). Thus, we have identified candidate pharmacogenomic biomarkers and novel pathways associated with METRO-TOPO therapy that will serve as a foundation for further investigation and validation of METRO-TOPO as a novel treatment option for prostate cancers.

ATM inhibitor KU-55933 induces apoptosis and inhibits motility by blocking GLUT1-mediated glucose uptake in aggressive cancer cells with sustained activation of Akt.

Enhanced glucose uptake is coupled with elevated aerobic glycolysis (the Warburg effect) in cancer cells and is closely correlated with increased tumor aggressiveness and poor prognosis. We previously discovered that ATM, a protein kinase deficient in Ataxia-telangiectasia (A-T) disease, is an insulin-responsive protein that participates in insulin-mediated glucose uptake in muscle cells by stimulating glucose transporter 4 (GLUT4) translocation. However, the role of ATM in glucose uptake and tumorigenesis of cancer cells is unclear. In the present study, we found that aggressive breast and prostate cancer cell lines with overactivated Akt activity exhibit enhanced glucose uptake and GLUT1 translocation upon insulin treatment, and KU-55933, a specific inhibitor of ATM, inhibits insulin-mediated glucose uptake by blocking translocation of GLUT1 to the cell surface. KU-55933 also inhibits aerobic glycolysis and ATP production in these cells. Moreover, KU-55933 induces apoptosis and inhibits motility of cancer cells by inhibiting glucose uptake. Our results showed that while high concentration of glucose and insulin promote the expression of a mesenchymal biomarker (vimentin) in these cancer cells, KU-55933 strongly inhibits its expression as well as epithelial to mesenchymal transition. The roles of ATM in stimulating glucose uptake, glycolysis, motility, and proliferation of cancer cells were demonstrated by knocking-down ATM in these cells. KU-55933 treatment also inhibits tumor growth and metastasis in vivo in mouse mammary tumors through inhibition of GLUT1 translocation and vimentin expression. These results suggest that ATM acts as a promoter of tumorigenesis in cancer cells with overactivated Akt, and KU-55933 induces apoptosis and inhibits motility by blocking GLUT1-mediated glucose uptake and glycolysis in these cancer cells, which may lead to the use of KU-55933 and its analogs as new preventive or therapeutic agents against cancer.

Paradoxical Role of Glypican-1 in Prostate Cancer Cell and Tumor Growth

Recent studies suggest that glypican-1 (GPC-1) is a biomarker for prostate cancer, but there are few studies elucidating the role of GPC-1 in prostate cancer progression. We observed high expression of GPC-1 in more aggressive prostate cancer cell lines such as PC-3 and DU-145. While inhibition of GPC-1 expression in PC-3 cells decreased cell growth and migration in vitro, it surprisingly increased cell proliferation and migration in DU-145 cells, suggesting that the role of GPC-1 is cell type-dependent. Further, GPC-1 inhibition increased PC-3 tumor size in NCr nude mice xenografts. We hypothesized that the discrepancy between the in vitro and in vivo data is mediated by stromal cells in the tumor microenvironment. Thus, we tested the effect of tumor conditioned media (TCM) on gene expression in human mesenchymal stem cells and fibroblasts. Treatment of stromal cells with TCM from PC-3 cells transfected with GPC-1 shRNA increased the expression of migration markers, endocrine/paracrine biomolecules, and extracellular matrix components. Additionally, the decreased cell growth in GPC-1 knockdown PC-3 cells was rescued by coculturing with stromal cells. These data demonstrate the paradoxical role that GPC-1 plays in prostate cancer cell growth by interacting with stromal cells and through ECM remodeling and endocrine/paracrine signaling.

Abstract LB-120: Acetylated Kruppel-like factor 5 and transforming growth factor-β mediated drug resistance in prostate cancer

Abstract Purpose: In this study, we explored the role of Kruppel-like factor 5 (KLF5) and its acetylated form on lysine 369 in transforming growth factor-β (TGFβ) induced drug resistance to promote antitumor synergy and overcome drug resistance in advanced stage prostate cancer. Procedures: Two aggressive prostate cancer cell lines DU 145 and PC-3 were treated with docetaxel to measure cytotoxicity. To assess docetaxel resistance, we used in-vitro cell survival assay, colony survival assay and xenograft mouse model. In addition, TGFβ1 and SB505124 (TGFβ receptor I inhibitor) were used to explore TGFβ induced docetaxel resistance. To measure function of KLF5 and its different acetylation form on lysine 369, stable cell lines were constructed with different KLF5 acetylation status mimics after knocking out endogenous KLF5, utilizing the CRISPR-Cas9 system. Results: We found that KLF5 alone induced docetaxel resistance in vivo, but not in vitro. Moreover, endogenous knocking out of KLF5 inhibited TGFβ induced docetaxel resistance. In addition to previous findings that TGFβ recruits P300 acetyl-transferase to acetylate KLF5 on lysine 369, we further found that TGFβ induced docetaxel resistance depends on acetylation of KLF5. In addition, Mass Spectrometry analysis revealed that JUNB, a downstream target of non-canonical TGFβ pathway, is a direct binding target of acetylated KLF5 but not de-acetylated KLF5. Knocking down of JUNB in acetylated KLF5 mimic cell line inhibited TGFβ induced docetaxel resistance. Conclusions: These suggested that acetylated KLF5 is indispensable in TGFβ induced drug resistance through interaction with JUNB. Our study introduced a novel mechanism of acetylated KLF5 and JUNB mediated docetaxel resistance in prostate cancer and contributed to an advanced therapy combination for advanced prostate cancer patients. Citation Format: Yixiang Li, Baotong Zhang, Jin-Tang Dong. Acetylated Kruppel-like factor 5 and transforming growth factor-β mediated drug resistance in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-120.

Abstract 2944: Identification of key transcriptomic and epigenomic factors influencing conventional and metronomic dosing in aggressive and non-aggressive prostate cancer

Abstract Repetitive, low-dose drug administration (metronomic; METRO) shows ability to overcome drug resistance and increased drug efficacy in many cancers, but the mechanisms are not understood fully. Previously we showed topotecan (TOPO) METRO dosing was more effective than conventional (CONV) dosing in aggressive prostate cancer cell lines and xenograft mouse models. To explore possible mechanisms by which METRO dosing alters tumor growth and metastases, we performed targeted mRNA and miRNA expression studies and identified potential candidate cancer pathway genes and miRNA-mRNA pairs as unique treatment-related biomarkers for alternative TOPO-METRO therapy. To determine drug response, Androgen-independent human prostate cancer cells (PC3), androgen-dependent (LNCaP) cell lines were treated with TOPO following CONV and METRO dosing schedules. Cancer pathway gene and micro-RNA expression profiles were assessed at the calculated IC50 of TOPO after each treatment. Expression signatures were identified using differential expression (DE) analysis software and a Spearman’s rank-based correlation was used to assess the association of drug response, mRNA and miRNA expression. Gene signatures associated with TOPO-METRO therapy were validated against patient profiles in The Cancer Genome Atlas (TCGA) and Genomic Data Commons (GDC) and protein expression of most significant genes by immunoblotting. We identified disparate treatment-related mRNA and miRNA expression signatures for TOPO-METRO vs CONV treatment. We also identified a gene signature (top five gene: SERPINB5, CDKN1A, TNF, FOS, & ANGPT1) for both PC-3 and LNCaP following TOPO-METRO dosing. Ingenuity Pathway Analysis identified that upregulation of tumor suppressor, anti-proliferative genes (eg, SERPINB5), genes involved in activation of the immune system (RPL13A) and down regulation of genes involved in apoptosis, invasion, metastasis, and inflammation (TNF, FOS, and MMP1) are likely vital to the observed treatment response. Epigenetic analysis showed distinct miRNA expression changes may influence differential gene expression (miRNA-mRNA pairs) for TOPO-METRO dosing. 20 miRNAs genes (including miR-30c, miR-19a, mir-20a, mir-17, let7i & let7b) were associated with TOPO cytotoxicity (p<0.05); seven of these bind to 28 mRNAs (p<0.05) as mRNA-miRNA pairs. Furthermore, we confirmed the top 5 significant genes (e.g. FOS, SERPINEB5, MMP9) for TOPO-Metro therapy by in-silico validation (TCGA). Overall, these studies address a fundamental gap in knowledge related to the effect of METRO dosing on genomic and epigenetic influences and overall treatment efficacy. Using genomics, transcriptomics and epigenomics approaches we determined gene signatures that may be used in identifying patients and personalizing their treatment with the goal of improving overall survival. Citation Format: Taraswi Mitra Ghosh, Joshua Davis, Grafton S. Barnett, Elena Skarupa, Jeff D. Warner, Brian S. Cummings, Robert D. Arnold. Identification of key transcriptomic and epigenomic factors influencing conventional and metronomic dosing in aggressive and non-aggressive prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2944.

HnRNPM, a potential mediator of YY1 in promotingthe epithelial-mesenchymal transition of prostate cancer cells.

With the popularity of serum prostate-specific antigen (PSA) screening, the number of newly diagnosed prostate cancer (PCa) patients is increasing. However, indolent or invasive PCa cannot be distinguished by PSA levels. Here, we mainly explored the role of heterogeneous nuclear ribonucleoprotein M (hnRNPM) in the invasiveness of PCa. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blot analysis was used to detect the expressions of hnRNPM in PCa and benign prostate hyperplasia (BPH) tissues as well as in PCa cell lines. Immunohistochemistry was applied to detect the hnRNPM or Yin Yang 1 (YY1) expression in BPH, prostate adenocarcinoma (ADENO) and neuroendocrine prostate cancer (NEPC) tissues. After aberrant, the expression of hnRNPM in C4-2 and PC3 cells, the changes of cell migration and invasion were observed through wound-healing and transwell assays. We also predicted the transcription factor of hnRNPM through databases, then verified the association of hnRNPM and YY1 using chromatin immunoprecipitation (ChIP) and luciferase assays. The expression level of hnRNPM is gradually reduced in BPH, ADENO, and NEPC tissues and it is less expressed in more aggressive PCa cell lines. Overexpression of hnRNPM can significantly reduce Twist1 expression, which inhibits the migration and invasion of PCa cells in vitro. In PCa cells, overexpression of YY1 can promote epithelial-mesenchymal transition by reducing hnRNPM expression. Furthermore, this effect caused by overexpression of YY1 can be partially attenuated by simultaneous overexpression of hnRNPM. Our study demonstrates that hnRNPM negatively regulated PCa cell migration and invasion, and its expression can be transcriptionally inhibited by YY1. We speculated that hnRNPM may be a biomarker to assist in judging the aggressiveness of PCa.

CRISPR/Cas9-mediated knockout of Lcn2 effectively enhanced CDDP-induced apoptosis and reduced cell migration capacity of PC3 cells

AimsLipocalin 2 (Lcn2/NGAL) belongs to lipocalin superfamily with diverse functions. The precise function of Lcn2, particularly in cancer development, remains to be elucidated yet. In an attempt to knockout of Lcn2 expression by CRISPR/Cas 9 technology in a highly aggressive and invasive prostate cancer cell line and to evaluate the combination therapy with cisplatin (CDDP), this study was conducted. Main methodsControl CRISPR/Cas9 plasmid and homology-directed repair plasmid or validated human Lcn2 CRISPR/Cas9 KO plasmids were co-transfected into PC3 cells using fugene HD transfection reagent. The stable cells were selected in the presence of puromycin. Correspondingly, knock out of Lcn2 was evaluated by RT-PCR, ELISA, and immunocytochemistry. PC3-Scr (control) and Lcn2-KO (PC3 cells in which lcn2 has been knocked out) were treated with or without cisplatin (CDDP). Cell proliferative ability was measured by WST-1 and colony-formation assays. Apoptosis was evaluated by DAPI staining, in situ cell death detection (TUNEL) assay, and cell death detection ELISA plus methods. The migration capabilities were studied by wound healing/scratch and transwell assays. Key findingsLcn2 knock out in a highly aggressive and invasive cancer cell like PC3 decreased cell proliferation and increased the sensitivity of CDDP. Conspicuously, loss of Lcn2 expression effectively enhanced CDDP-induced apoptosis in PC3 cells. Lcn2 knock out by CRISPR/Cas9 technology decreased the cell migration capacity of PC3 cells as well. SignificanceLcn2 not only is a valuable and useful biomarker for diagnosis and prognosis of prostate cancer but also and more importantly is a potential novel emerging therapeutic target.

Co-expression of an engineered cell-surface sialidase by CART cells improves anti-cancer activity of NK cells in solid tumors

Background & Aim Clinical success of CART cells targeting CD19 has led to FDA approval for a wide-range of hematological malignancies. Despite these achievements, CARs have lacked efficacy in the treatment of solid tumors due to a number of challenges, including overcoming the dense immunosuppressive tumor stroma and post-translational modifications on the tumor that favor survival. Our work aims to improve CART cell therapy against solid tumors by targeting the tumor-specific glycoepitope Tn-MUC1, and enhancing cytotoxic effects of endogenous and unmodified immune cells by engineering sialidase function on CART cells. Previous studies have demonstrated precedence for this approach showing that coupling current immunotherapies with glycoediting activity increases therapeutic efficacy. For example, CART cells engineered to express heparanase showed an improved degradation of the extracellular matrix, which promoted T cell infiltration of the tumor and antitumor activity. Additionally, sialidase activity coupled to trastuzumab enhanced endogenous NK anti-cancer efficacy. Methods, Results & Conclusion Here, we present a cellular therapeutic approach where we designed a novel cell-surface human sialidase and expressed it on CART cells targeting Tn-MUC1. Truncated, cancer-specific glycoforms, such as Tn-MUC1, are thought to play a role in decreasing cell-cell interactions and increasing the metastatic potential of cancer cells. We established that Tn-MUC1-CART (or 5E5-CART) cells induce minimal cytotoxic effects against the aggressive PC3 prostate cancer cell line, when co-cultured alone at equal effector:target ratios. When PC3 cells are treated with a Clostridium perfringens-derived sialidase, NK cells and 5E5-CART cells show enhanced IFN-γ production and improved cytotoxic effects are observed compared with NK cells and 5E5-CART cells alone. Similarly, these effector enhancements are observed in the presence of T cells presenting a human cell-surface sialidase. Taken together, these data suggest that glycoediting of tumor sialic acid presents a rational and unique opportunity to overcome barriers for adoptive immunotherapies in solid tumors, and engagement of the endogenous immune system by adoptively transferred cells is an effective strategy for improved anti-tumor activity.

AKR1C3, a crucial androgenic enzyme in prostate cancer, promotes epithelial-mesenchymal transition and metastasis through activating ERK signaling

BackgroundAKR1C3, as a crucial androgenic enzyme, facilitates intratumoral androgen biosynthesis and androgen receptor activation in castration-resistant prostate cancer (PCa). The data has shown that AKR1C3 expression is significantly elevated in clinical metastatic PCa specimens, indicating a potential role of AKR1C3 in PCa metastasis. MethodsC4-2, 22RV1-T, and PC-3 cells with higher AKR1C3 expression were selected and treated with several specific AKR1C3 shRNAs or small molecule inhibitor, and the cell migration and invasion abilities were detected by wound healing assay and Transwell assay. The expression of several epithelial-mesenchymal transition (EMT) markers (i.e., E-cadherin and vimentin) and the related transcription factors (i.e., ZEB1, TWIST1, and SLUG) was examined by Western blot or quantitative PCR assays, and the phosphorylation of AKT or ERK was detected by Western blot. Also, subcutaneous xenografts with 22RV1-T sublines were used to detect in vivo tumor growth, and the expression of E-cadherin, vimentin, and ZEB1 by immunohistochemical staining. The correlation between AKR1C3 and EMT marker expression in clinical specimens was analyzed. ResultsAKR1C3 was overexpressed in more aggressive PCa cell lines regardless of the androgen receptor status. Knockdown of AKR1C3 expression or inhibition of AKR1C3 activity could significantly suppress cell migration and invasion abilities in vitro, and increase E-cadherin expression but decrease vimentin expression, in which the phosphorylation of ERK and the EMT-associated transcription factor expression were specifically down-regulated. Also, knockdown of AKR1C3 could suppress PCa tumorigenesis and reverse EMT in vivo. Moreover, there was a significant correlation between AKR1C3 expression and EMT in human PCa specimens from public tissue microarray. ConclusionsAKR1C3 is a novel EMT driver in PCa metastasis through activating ERK signaling.

NAC1 promotes the migration of prostate cancer cells and participates in osteoclastogenesis by negatively regulating IFNβ.

Nucleus accumbens-associated protein 1 (NAC1), a transcriptional co-regulator, is overexpressed in advanced prostate cancer. However, the NAC1-regulated transcriptome has not been completely explored. In the present study, the functional silencing of NAC1 blocked the migration of prostate cancer cells and suppress osteoclastogenesis. The present study also determined that NAC1 was overexpressed in the highly aggressive prostate cancer cell lines PC-3, DU-145 and LNCaP. NAC1 small interfering RNA treatment of DU-145 cells decreased cell migration, but interestingly had no significant effects on cell proliferation. Furthermore, microarray analysis showed that a group of genes may be associated with the development of prostate cancer after NAC1 knockdown, including interferon-β (IFNβ), which is reported to be involved in osteoclastogenesis, an important factor affecting bone metastasis. The mechanisms of NAC1 function were further explored by co-culture studies using PC-3 and RAW264.7 osteoclast precursor cells, which demonstrated that silencing NAC1 downregulated the genes associated with the activation of osteoclasts. Furthermore, it was revealed that NAC1 had the ability to affect the release of IFNβ into the extracellular environment. Together, these findings indicated that NAC1 promoted cell migration, and that NAC1 may have a key role in osteoclastogenesis.

MiR‑138 modulates prostate cancer cell invasion and migration via Wnt/β‑catenin pathway

The prognosis for prostate cancer patients with distant metastasis is poor, with an average survival rate of 24‑48months. The exact mechanisms underlying prostate cancer metastasis remain to be elucidated, despite previous research efforts. The present study aimed to reveal the regulatory roles of miR‑138 via Wnt/β‑catenin pathway in prostate cancer cell migration and invasion. Reverse transcription‑quantitative polymerase chain reaction was used to examine the mRNA and protein expression levels and transwell assay was conducted to determine cell invasion and migration. A luciferase reporter assay was used to determine the target association between miR‑138 and β‑catenin. The present study identified microRNA (miR)‑138 as an invasion and migration regulator in prostate cancer. miR‑138 was downregulated in aggressive prostate cancer cell lines. Furthermore, followingmiR‑138 overexpression, prostate cancer cells exhibited impaired invasive and migratory abilities. E‑cadherin was upregulated and vimentin was downregulated. In addition, it was demonstrated that miR‑138 negatively regulated the Wnt/β‑catenin pathway activation in prostate cancer. The pathway was then activated via β‑catenin overexpression and this reversed the effects of miR‑138. The results suggest that miR‑138 downregulation may contribute to prostate cancer progression and metastasis. The findings provide a novel molecular therapeutic target in the treatment of prostate cancer metastasis.

Metabolic Differences in Glutamine Utilization Lead to Metabolic Vulnerabilities in Prostate Cancer

The new oncologic paradigm of precision medicine is focused on identifying metabolic, proteomic, transcriptomic and genomic variabilities in tumors that can be exploited to tailor treatments and improve patient outcomes. Metabolic changes are a hallmark of cancer, and inhibition of metabolic pathways is now a major strategy in medicinal chemistry for targeting cancers. However, non-invasive biomarkers to categorize metabolic subtypes are in short supply. The purpose of this study was to characterize the intracellular and extracellular metabolic profiles of four prostate cancer cell lines with varying degrees of aggressiveness. We observed metabolic differences between the aggressive prostate cancer cell line PC3 and the even more aggressive, metastatic subline PC3M assessed by hyperpolarized in vivo pyruvate studies, nuclear magnetic resonance spectroscopy, and carbon-13 feeding studies. On further examination of the differences between these two cell lines, we found increased glutamine utilization in the metastatic PC3M subline that led directly to sensitivity to glutaminase inhibitor CB-839. Our study supports the theory that metastatic progression increases glutamine utilization and the inhibition of glutaminolysis could have clinical implications.

Sirtuin 7: a new marker of aggressiveness in prostate cancer.

Predictive biomarkers for advanced prostate cancer (PCa) are still missing. The sirtuin 7 (SIRT7) has been linked to tumorogenesis but its role in prostate cancer is poorly documented. To determine if SIRT7 can be a biomarker for aggressive prostate cancer and plays a role in PCa aggressiveness. We analyzed the expression of SIRT7 by immunohistochemistry in 57 patients comparing healthy with adjacent cancer tissue. SIRT7 levels were significantly elevated in tumors and its expression was positively associated with the grade. We also demonstrated that the knock down of SIRT7 decreased the migration of DU145 and PC3 cells (two androgen-independent prostate cancer cell lines) whereas the overexpression of the native protein but not the mutated form increased the cell migration and the invasion of the poorly aggressive prostate cancer cell line LNCaP. Finally, we also showed that SIRT7 overexpression induced the resistance to docetaxel. Our results demonstrate that SIRT7 promotes prostate cancer cell aggressiveness and chemoresistance and suggest that SIRT7 is a good predictive biomarker of PCa aggressiveness.

Site-Specific Fucosylation Analysis Identifying Glycoproteins Associated with Aggressive Prostate Cancer Cell Lines Using Tandem Affinity Enrichments of Intact Glycopeptides Followed by Mass Spectrometry.

Fucosylation (Fuc) of glycoproteins plays an important role in regulating protein function and has been associated with the development of several cancer types including prostate cancer (Pca). Therefore, the research of Fuc glycoproteins has attracted increasing attention recently in the analytical field. Herein, a strategy based on lectin affinity enrichments of intact glycopeptides followed by mass spectrometry has been established to evaluate the specificities of various Fuc-binding lectins for glycosite-specific Fuc analysis of nonaggressive (NAG) and aggressive (AG) Pca cell lines. The enrichment specificities of Fuc glycopeptides using lectins (LCA, PSA, AAL, LTL, UEA I, and AOL) and MAX extraction cartridges alone, or in tandem, were evaluated. Our results showed that the use of lectin enrichment significantly increased the ratio of fucosylated glycopeptides to total glycopeptides compared to MAX enrichment. Furthermore, tandem use of lectin followed by MAX increased the number of identifications of Fuc glycopeptides compared to using lectin enrichment alone. LCA, PSA, and AOL showed stronger binding capacity than AAL, LTL, and UEA I. Also, LCA and PSA bound specifically to core Fuc, whereas AOL, AAL, and UEA I showed binding to both core Fuc and branch Fuc. The optimized enrichment method with tandem enrichment of LCA followed by MAX (LCA-MAX) was then applied to examine the Fuc glycoproteomes in two NAG and two AG Pca cell lines. In total, 973 intact Fuc glycopeptides were identified and quantified from 252 Fuc proteins by using the tandem-mass-tags (TMT) labeling and nanoliquid chromatography-mass spectrometry (nanoLC-MS/MS) analysis. Further data analysis revealed that 51 Fuc glycopeptides were overexpressed more than 2-fold in AG cell lines compared to NAG cells. The analysis of protein core fucosylation has great potential for aiding our understanding of invasive activity of AG Pca and may lead to the development of diagnostic approaches for AG Pca.

Abstract 4207: Selective drug sensitivity score (DSS) for indolent and aggressive prostate cancer cell lines

Abstract Prostate cancer (PC) is the most common malignancy in men and the second leading cause of cancer-related deaths. The majority of the PCs are classified as adenocarcinomas characterized by the expression of androgen receptor (AR) and prostate-specific antigen (PSA). Two of the most commonly used cell lines are LNCaP and PC-3 cells, derived from lymph node and bone metastases, respectively. Also VCaP cells, derived from vertebral metastases, are widely used in prostate cancer research. It has been well established that LNCaP and VCaP cells represent the conventional indolent form of PC expressing AR and PSA and are androgen-dependent. PC-3 cells, on the other hand, do not express AR and PSA, are androgen-independent, and represent the highly aggressive form. The drug sensitivity of the cell lines was assessed by applying a large panel of drugs covering cancer chemotherapeutics and clinically available and emerging drugs including conventional chemotherapy, kinase inhibitors, metabolic modifiers, rapalogs, differentiating/epigenetic modifiers, kinesin inhibitors, apoptotic modulators, NSAIDs, hormone therapy, immunomodulators and HSP inhibitors. A panel of 460 compounds was tested in five concentrations covering a 10.000-fold drug-relevant concentration range in 384-well format. Cells were seeded to pre-drugged plates, followed by cell viability measurements (CellTiter-Glo) after 72 hours. Maximal and minimal responses to drugs were analyzed, the EC50 values were calculated and Drug Sensitivity Score (DSS) was calculated for each drug as a measure of reduced viability. A selective Drug Sensitivity Score (sDSS) was calculated to identify the selective drug response pattern of each three cancer cell lines. As expected, the results indicate that LNCaP and VCaP cells in general were more sensitive to drugs of different categories than PC-3 cells. According to DSS analysis, all three cell lines showed sensitivity to conventional chemotherapy and kinase inhibitors. However, PC-3 cells were more sensitive to kinase inhibitors than conventional chemotherapy. Determining sDSS revealed specific sensitivities of each cell line. LNCaP cells were sensitive to kinase inhibitors, such as mTOR and AKT inhibitors. Also VCaP cells showed selective sensitivity to kinase inhibitors, especially Aurora kinase and IGF1R inhibitors. In addition to kinase inhibitors, VCaP cells were selectively sensitive to HDAC inhibitors. Furthermore, PC-3 cells were sensitive to e.g. CDK inhibitors. We conclude that the cell-based compound screening combined with DSS and sDSS analysis provides a possibility to profile cellular responses to an extensive collection of anti-cancer compounds enabling repurposing of existing drugs to new indications, identification of vulnerabilities in different types of cancer cells and functional investigation of cellular pathways behind drug sensitivity or resistance. Citation Format: Jenni Mäki-Jouppila, Jenni Bernoulli, Johanna Tuomela, Mari I. Suominen, Jussi M. Halleen, Sanna Timonen, Elina Huovari, Katja Suomi, Swapnil Potdar, Päivi Östling, Jani Saarela, Katja M. Fagerlund. Selective drug sensitivity score (DSS) for indolent and aggressive prostate cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4207. doi:10.1158/1538-7445.AM2017-4207

Peptide Agonists of Vasopressin V2 Receptor Reduce Expression of Neuroendocrine Markers and Tumor Growth in Human Lung and Prostate Tumor Cells.

Neuroendocrine tumors (NETs) comprise a heterogeneous group of malignancies that express neuropeptides as synaptophysin, chromogranin A (CgA), and specific neuronal enolase (NSE), among others. Vasopressin (AVP) is a neuropeptide with an endocrine, paracrine, and autocrine effect in normal and pathological tissues. AVP receptors are present in human lung, breast, pancreatic, colorectal, and gastrointestinal tumors. While AVP V1 receptors are associated with stimulation of cellular proliferation, AVP V2 receptor (V2r) is related to antiproliferative effects. Desmopressin (dDAVP) is a synthetic analog of AVP that acts as a selective agonist for the V2r, which shows antitumor properties in breast and colorectal cancer models. Recently, we developed a derivative of dDAVP named [V4Q5]dDAVP, which presents higher antitumor effects in a breast cancer model compared to the parental compound. The goal of present work was to explore the antitumor properties of the V2r agonist dDAVP and its novel analog [V4Q5]dDAVP on aggressive human lung (NCI-H82) and prostate cancer (PC-3) cell lines with neuroendocrine (NE) characteristics. We study the presence of specific NE markers (CgA and NSE) and V2r expression in NCI-H82 and PC-3. Both cell lines express high levels of NE markers NSE and CgA but then incubation with dDAVP diminished expression levels of both markers. DDAVP and [V4Q5]dDAVP significantly reduced proliferation, doubling time, and migration in both tumor cell cultures. [V4Q5]dDAVP analog showed a higher cytostatic effect than dDAVP, on cellular proliferation in the NCI-H82 cell line. Silencing of V2r using small interfering RNA significantly attenuated the inhibitory effects of [V4Q5]dDAVP on NCI-H82 cell proliferation. We, preliminarily, explored the in vivo effect of dDAVP and [V4Q5]dDAVP on NCI-H82 small cell lung cancer xenografts. Treated tumors (0.3 μg kg−1, thrice a week) grew slower in comparison to vehicle-treated animals. In this work, we demonstrated that the specific agonists of V2r, dDAVP, and [V4Q5]dDAVP displays antitumor capacity on different human models of lung and prostate cancers with NE features, showing their potential therapeutic benefits in the treatment of these aggressive tumors.

239 - Differential drug sensitivity score (DSS) for indolent and aggressive prostate cancer cell lines

239 - Differential drug sensitivity score (DSS) for indolent and aggressive prostate cancer cell lines