Metastasis Of Prostate Cancer Cells Research Articles

Cerebral Cavernous Malformation 1 Determines YAP/TAZ Signaling-Dependent Metastatic Hallmarks of Prostate Cancer Cells.

Simple SummaryOur analysis of cerebral cavernous malformation 1 (CCM1) expression and function reveals a candidate predictive biomarker for prostate cancer metastasis and provides evidence that CCM1 abnormality can be pathogenic in prostate cancer. In particular, the CCM1 regulation of metastasis appears as a common molecular event in metastatic prostate cancer cells arising from disparate genetic backgrounds.Enhanced Yes-associated protein (YAP)/transcriptional co-activator with PDZ-binding motif (TAZ) signaling is correlated with the extraprostatic extension of prostate cancer. However, the mechanism by which YAP/TAZ signaling becomes hyperactive and drives prostate cancer progression is currently unclear. In this study, we revealed that higher expression of CCM1, which is uniquely found in advanced prostate cancer, is inversely correlated with metastasis-free and overall survival in patients with prostate cancer. We also demonstrated that CCM1 induces the metastasis of multiple types of prostate cancer cells by regulating YAP/TAZ signaling. Mechanistically, CCM1, a gene mutated in cerebral cavernous malformation, suppresses DDX5, which regulates the suppression of YAP/TAZ signaling, indicating that CCM1 and DDX5 are novel upstream regulators of YAP/TAZ signaling. Our findings highlight the importance of CCM1-DDX5-YAP/TAZ signaling in the metastasis of prostate cancer cells.

PAX5-induced upregulation of LINC01194 exerts oncogenic properties by regulating GOLPH3 expression via miR-486-5p in prostate cancer.

Several studies have demonstrated that long non-coding RNA can act as crucial roles during the progression of various tumors, including prostate cancer (PCa). We aimed to determine lncRNA LINC01194(LINC01194) expression in prostate cancer (PCa) and examine its influence on tumor behaviors of PCa cells. RT-PCR was performed to examine LINC01194 and PAX5's expression levels in PCa tissues and cell lines. Luciferase reporter and chromatin immunoprecipitation (ChIP) assays were performed to explore whether PAX5 could activate the transcription of LINC01194. Cell viability, migration and invasion were assessed by CCK-8, colony formation, transwell assay and Wound-healing assays. Bioinformatics and Dual-Luciferase assays were used to investigate the interaction between LINC01194 and miR-486-5p, as well as between miR-486-5p and GOLPH3. Western blot was applied for detecting the expressions of the related proteins. LINC01194 was highly expressed in PCa specimens and cell lines. PAX5 could bind directly to LINC01194 promoter region and activate its transcription. Functionally, the proliferation and metastasis of PCa cells were substantially impeded by LINC01194 silencing in vitro and in vivo. Mechanistically, LINC01194 promoted PCa progression by serving as a sponge of miR-486-5p to increase GOLPH3 expression. Our study identifies LINC01194 as a tumor promotor in PCa and implicates the LINC01194/miR-486-5p/GOLPH3 axis in the PCa progression.

LncRNA KCNQ1OT1 Promotes Proliferation, Invasion and Metastasis of Prostate Cancer by Regulating miR-211-5p/CHI3L1 Pathway.

BackgroundBone metastasis after failure of castration therapy is the main reason of death in patients with prostate cancer (PCa). Therefore, full awareness of the metastasis mechanism of PCa and discovery of new therapeutic targets are necessary. Studies showed that lncRNA was involved in the development of cancer. However, its potential role and molecular mechanism in PCa metastasis are still unclear. YKL-40 is an 18 glycosyl hydrolase family protein encoded by CHI3L1, which is involved in the invasion and metastasis of various tumors. A previous study of the authors found that YKL-40 was related to the invasion and metastasis of PCa cells. However, the cause of its abnormal expression in PCa remains unclear. The present study explored the role of lncRNA KCNQ1OT1/miR-211-5p/CHI3L1 regulatory axis in the proliferation, invasion, and metastasis of PCa.MethodsRT-PCR and Western blot were used to measure the expression profiles of KCNQ1OT1 and YKL. CCK-8 and Transwell assays were used to examine their effects on cell proliferation and migration. Double luciferase reporter assay was used to verify the interactions between miR-211-5p and CHI3L1 3′-UTR.ResultsKCNQ1OT1 expression was upregulated in PCa tissues and cells. Downregulating this expression inhibited PCa cell invasion, proliferation, and metastasis. KCNQ1OT1 bound miR-211-5p competitively, and miR-211-5p targeted CHI3L1 3′-UTR. miR-211-5p expression was downregulated, whereas CHI3L1 (YKL-40) expression was upregulated. miR-211-5p levels were negatively correlated with KCNQ1OT1 expression and CHI3L1 mRNA. The decrease in YKL-40 expression in PCa cells induced by the downregulation of KCNQ1OT1 expression could be offset by miR-211-5p inhibitor transfection.ConclusionThis study showed that lncRNA KCNQ1OT1, as a ceRNA, upregulated CHI3L1 and promoted PCa progression through competitive binding to miR-211-5p.

The role of S100A4 for bone metastasis in prostate cancer cells

BackgroundProstate cancers frequently metastasize to bone, where the best microenvironment for distant colonization is provided. Since osteotropic metastasis of prostate cancer is a critical determinant of patients’ survival, searches for preventive measures are ongoing in the field. Therefore, it is important to dissect the mechanisms of each step of bone metastasis, including the epithelial-mesenchymal transition (EMT) and cross-talk between metastatic niches and cancer cells.MethodsIn this study, we established a highly bone-metastatic subline of human prostate cancer cells by selecting bone-homing population of PC3 cells after cardiac injection of eight-week-old male BALB/c-nude mice. Then we assessed the proliferation, EMT characteristics, and migration properties of the subline (mtPC3) cells in comparison with the parental PC3 cells. To investigate the role of S100A4, we performed gene knock-down by lentiviral transduction, or treated cells with recombinant S100A4 protein or a S100A4-neutralizing antibody. The effect of cancer cells on osteoclastogenesis was evaluated after treatment of pre-osteoclasts with conditioned medium (CM) from cancer cells.ResultsThe mtPC3 cells secreted a markedly high level of S100A4 protein and showed elevated cell proliferation and mesenchymal properties. The increased proliferation and EMT traits of mtPC3 cells was inhibited by S100A4 knock-down, but was not affected by exogenous S100A4. Furthermore, S100A4 released from mtPC3 cells stimulated osteoclast development via the cell surface receptor RAGE. Down-regulation or neutralization of S100A4 in the CM of mtPC3 cells attenuated cancer-induced osteoclastogenesis.ConclusionAltogether, our results suggest that intracellular S100A4 promotes cell proliferation and EMT characteristics in tumor cells, and that secreted S100A4 activates osteoclastogenesis, contributing to osteolytic bone metastasis. Thus, S100A4 upregulation in cancer cells highly metastatic to bone might be a key element in regulating bone metastasis.

Long Non-Coding RNA (lncRNA) RAMS11 Promotes Metastatis and Cell Growth of Prostate Cancer by CBX4 Complex Binding to Top2α.

IntroductionStudies have confirmed that parts of the non-coding genes in the human genome play an important role in the pathogenesis and metastasis of prostate cancer. Among them, long non-coding RNAs (lncRNAs) are vitally involved in the biological regulation of prostate cancer. In addition, lncRNAs are closely associated with the recurrence, metastasis and prognosis of prostate cancer. However, the molecular pathogenesis of lncRNAs in regulating cell growth and metastasis of prostate cancer remains unclear. Therefore, this study was designed to explore the function and mechanism of lncRNA RAMS11 in cell growth and metastasis of prostate cancer.MethodsProstate cancer and para-carcinoma tissue samples were obtained from 42 patients who were diagnosed from March 2013 to September 2014 at Quanzhou First Hospital Affiliated to Fujian Medical University. Microarray experiments and real-time polymerase chain reaction (PCR) measured the expression of lncRNA. RWPE-2, LNCap, PC3 and DU145 cells were used for an in vitro model.ResultsThe expression of lncRNA RAMS11 was up-regulated in prostate cancer tissue samples. LncRNA RAMS11 promoted cell growth and metastasis of prostate cancer cells. Down-regulation of lncRNA RAMS11 attenuated cell growth and metastasis of prostate cancer cells. We also demonstrated that lncRNA RAMS11 bound to CBX4 to activate expression of Top2α. LncRNA RAMS11 promoted tumor growth of prostate cancer in the mouse model. The inhibition of CBX4 attenuated the pro-cancer effects of lncRNA AMS11 in prostate cancer cells, while the activation of Top2α attenuated the anti-cancer effects of si-lncRNA RAMS11 in prostate cancer cells.DiscussionOur results indicated that lncRNA RAMS11 promoted cell growth and metastasis of prostate cancer by CBX4 complex via binding to Top2α, and might be developed for the treatment of prostate cancer.

Inhibitory role of circRNA_100395 in the proliferation and metastasis of prostate cancer cells.

ObjectiveCircular RNAs (circRNAs) are non-coding RNAs with high cancer-specific expression and the potential for regulating tumorigenesis. CircRNA_100395 is expressed at low levels in many cancers and is involved in the regulation of tumor cell proliferation and metastasis. However, its expression and function in prostate cancer remain unclear.MethodsEndogenous expression levels of circRNA_100395 and microRNA-1228 (miR-1228) in prostate cancer tissue samples and cell lines were detected by quantitative reverse transcription-polymerase chain reaction. Cell proliferation, invasion, and migration, cell cycle distribution, and epithelial–mesenchymal transition (EMT) were analyzed in circRNA_100395-overexpressing prostate cancer cells by Cell Counting Kit-8, flow cytometry, Transwell assay, and western blotting, respectively.ResultsCircRNA_100395 expression was downregulated in cancerous prostate tissues relative to adjacent normal tissues. CircRNA_100395 expression was negatively correlated with tumor size, Gleason score, tumor stage, and lymph node metastasis. Moreover, circRNA_100395 overexpression inhibited cell proliferation, altered cell cycle distribution, reduced cell migration and invasion abilities, and suppressed EMT in prostate cancer cells. Moreover, miR-1228 was a direct downstream target of circRNA_100395, and the anti-tumor ability of circRNA_100395 was significantly reversed by miR-1228.ConclusionThis study identified circRNA_100395 as an anti-tumor circRNA and a potential therapeutic target for prostate cancer.

The use of zebrafish model in prostate cancer therapeutic development and discovery.

Zebrafish is now among the leading in vivo model for cancer research, including prostate cancer. They are an alternative economic model being used to study cancer development, proliferation, and metastasis. They can also be effectively utilized for the development of cancer drugs at all levels, including target validation, and high-throughput screening for possible lead molecules. In this review, we provide a comprehensive overview of the role of zebrafish as an in vivo model in prostate cancer research. Globally, prostate cancer is a leading cause of death in men. Although many molecular mechanisms have been identified as playing a role in the pathogenesis of prostate cancer, there is still a significant need to understand the initial events of the disease. Furthermore, current treatments are limited by the emergence of severe toxicities and multidrug resistance. There is an essential need for economical and relevant research tools to improve our understanding and overcome these problems. This review provides acomprehensive summary of studies that utilized zebrafish for different aims in prostate cancer research. We discussthe use of zebrafish in prostate cancer cell proliferation and metastasis, defining signaling pathways, drug discovery and therapeutic development against prostate cancer, and toxicity studies. Finally, this review highlights limitations in this field and future directions to efficiently use zebrafish as a robust model for prostate cancer therapeutics development.

RNA interference mediated suppression of TRPV6 inhibits the progression of prostate cancer in vitro by modulating cathepsin B and MMP9 expression.

PurposeThe transient receptor potential vanilloid 6 (TRPV6) channel is overexpressed in prostate cancer and its silencing is known to inhibit the growth of LNCaP cells. However, the role of TRPV6 in the metastasis of prostate cancer cells and its relationship to the invasive markers, matrix metalloproteinase (MMP) and cathepsin B, is unclear. Thus, the present study was focused on understanding these tumor-related processes.Materials and MethodsWe performed a wound-healing assay and a Transwell migration and invasion assay to assess the migration and invasion of prostate cancer cells. Western blot analysis was used to measure the expression of cathepsin B, MMP2, and MMP9.ResultsTRPV6 siRNA significantly inhibited the proliferation of LNCaP prostate cancer cells. It also significantly attenuated the wound healing and migration capacities of LNCaP cells. Moreover, the invasiveness of LNCaP cells and the expression of MMP9 and cathepsin B in LNCaP cells were also significantly inhibited by TRPV6 siRNA.ConclusionsThe results indicate that TRPV6 may promote prostate cancer progression in association with MMP9 and cathepsin B, thereby validating further research into TRPV6 as a useful therapeutic target for local invasion or metastasis of advanced prostate cancer.

Atypical PKCs activate Vimentin to facilitate prostate cancer cell motility and invasion

ABSTRACT Atypical protein kinase C (aPKC) are involved in progression of many human cancers. Vimentin is expressed during epithelial to mesenchymal transition (EMT). Molecular dynamics of Vimentin intermediate filaments (VIFs) play a key role in metastasis. This article is an effort to provide thorough understanding of the relationship between Vimentin and aPKCs . We demonstrate that diminution of aPKCs lead to attenuate prostate cellular metastasis through the downregulation of Vimentin expression. siRNA knocked-down SNAIL1 and PRRX1 reduce aPKC activity along with Vimentin. Results suggest that aPKCs target multiple activation sites (Ser33/39/56) on Vimentin and therefore is essential for VIF dynamics regulation during the metastasis of prostate cancer cells. Understanding the aPKC related molecular mechanisms may provide a novel therapeutic path for prostate carcinoma.

Silencing of METTL3 effectively hinders invasion and metastasis of prostate cancer cells.

Background: Since primary prostate cancer (PCa) can advance to the life-threatening metastatic PCa, exploring the molecular mechanisms underlying PCa metastasis is crucial for developing the novel targeted preventive strategies for decreasing the mortality of PCa. RNA N6-methyladenosine (m6A) is an emerging regulatory mechanism for gene expression and its specific roles in PCa progression remains elusive.Methods: Western blotting, quantitative real-time PCR and immunohistochemical analyses were used to detect target gene expression in PCa cells in vitro and prostate tissues from patients. RNA immunoprecipitation was conducted to analyze the specific binding of mRNA to the target protein. Migration and invasion assays were used to assess the migratory capacities of cancer cells. The correlation between target gene expression and survival rate of PCa patients was analyzed based the TCGA database.Results: We found that total RNA N6-methyladenosine (m6A) modification levels were markedly upregulated in human PCa tissues due to increased expression of methyltransferase like 3 (METTL3). Further studies revealed that the migratory and invasive capacities of PCa cells were markedly suppressed upon METTL3 knockdown. Mechanistically, METTL3 mediates m6A modification of USP4 mRNA at A2696, and m6A reader protein YTHDF2 binds to and induces degradation of USP4 mRNA by recruiting RNA-binding protein HNRNPD to the mRNA. Decrease of USP4 fails to remove the ubiquitin group from ELAVL1 protein, resulting in a reduction of ELAVL1 protein. Lastly, downregulation of ELAVL1 in turn increases ARHGDIA expression, promoting migration and invasion of PCa cells.Conclusions: Our findings highlight the role of METTL3 in modulating invasion and metastasis of PCa cells, providing insight into promising therapeutic strategies for hindering PCa progressing to deadly metastases.

Loss of exosomal miR-146a-5p from cancer-associated fibroblasts after androgen deprivation therapy contributes to prostate cancer metastasis

BackgroundAndrogen deprivation therapy (ADT) is the backbone of therapy for advanced prostate cancer (PCa). Despite the good initial response, castration resistance and metastatic progression will inevitably occur. Cancer-associated fibroblasts (CAFs) may be implicated in promoting metastasis of PCa after ADT. Our aim is to investigate the role and mechanism of CAFs-derived exosomes involving in metastasis of PCa after ADT.MethodsPCa cells were co-cultured with exosomes derived from 10 nM dihydrotestosterone (DHT)-treated (simulating the high androgen level of prostate cancer microenvironment) or ethanol (ETOH) -treated (simulating the castration level of prostate cancer microenvironment after ADT) CAFs, and their migration and invasion differences under castration condition were examined both in vitro and in vivo. The miRNA profiles of exosomes derived from DHT-treated CAFs and matched ETOH-treated CAFs were analysed via next generation sequencing. The transfer of exosomal miR-146a-5p from CAFs to PCa cells was identified by fluorescent microscopy. The function and direct target gene of exosomal miR-146a-5p in PCa cells were confirmed through Transwell assays, luciferase reporter, and western blot.ResultsCompared with DHT-treated CAFs, exosomes derived from ETOH-treated CAFs dramatically increased migration and invasion of PCa cells under castration condition. MiR-146a-5p level in exosomes from ETOH-treated CAFs was significantly reduced. The loss of miR-146a-5p may strengthen the epithelial-mesenchymal transition (EMT) to accelerate cancer cells metastasis by modulating epidermal growth factor receptor (EGFR)/ERK pathway.ConclusionsCAFs-derived exosomal miR-146a-5p confers metastasis in PCa cells under ADT through the EGFR/ERK pathway and it may present a new treatment for PCa.

Capping protein regulator and myosin 1 linker 3 regulates transcription of key cytokines in activated phagocytic cells

We have recently reported that capping protein regulator and myosin 1 linker 3 (CARMIL3), first identified as an oncofetal-like gene, is required for metastasis of breast and prostate cancer cells via regulating the actin cytoskeletal dynamics near the plasma membrane. Here, we demonstrate a novel function of CARMIL3 as an essential regulator of the transcription of several key proinflammatory cytokines in macrophages engulfing apoptotic cells and/or exposed to lipopolysaccharides (LPS). CARMIL3-deficient macrophages expressed strongly abrogated levels of interleukin (IL)-6, TNF-α, IL-1β and IL-23 in response to LPS, whereas IL-10 expression was enhanced. An RNA-seq analysis of CARMIL3-deficient and wild-type (WT) RAW264.7 cells stimulated with LPS revealed many differentially expressed genes, impacting several important inflammatory pathways. At the molecular level, CARMIL3 deficiency caused a strong impairment in LPS-activated nuclear factor-κB (NF-κB) signaling with decreased IKKα/β and IκBα phosphorylation and severely reduced p65 protein levels. This study uncovers a crucial role of CARMIL3 in impacting the balance between inflammation and tissue homeostasis via regulating major cytokines production in phagocytic cells.

Plectin is a regulator of prostate cancer growth and metastasis.

Prostate cancer is responsible for over 30,000 US deaths annually, attributed largely to incurable metastatic disease. Here, we demonstrate that high levels of plectin are associated with localized and metastatic human prostate cancer when compared to benign prostate tissues. Knock-down of plectin inhibits prostate cancer cell growth and colony formation in vitro, and growth of prostate cancer xenografts in vivo. Plectin knock-down further impairs aggressive and invasive cellular behavior assessed by migration, invasion, and wound healing in vitro. Consistently, plectin knock-down cells have impaired metastatic colonization to distant sites including liver, lung, kidney, bone, and genitourinary system. Plectin knock-down inhibited number of metastases per organ, as well as decreased overall metastatic burden. To gain insights into the role of plectin in prostate cancer growth and metastasis, we performed proteomic analysis of prostate cancer plectin knock-down xenograft tissues. Gene set enrichment analysis shows an increase in levels of proteins involved with extracellular matrix and laminin interactions, and a decrease in levels of proteins regulating amino acid metabolism, cytoskeletal proteins, and cellular response to stress. Collectively these findings demonstrate that plectin is an important regulator of prostate cancer cell growth and metastasis.

A novel DNA methylation 10-CpG prognostic signature of disease-free survival reveal that MYBL2 is associated with high risk in prostate cancer

ABSTRACT Background Prostate cancer (PC) is the most common non-cutaneous malignancy among men in the western world. However, heterogeneity remains a pressing clinical problem. Research design and methods The least absolute shrinkage and selection operator (LASSO) was used to screen the prognostic signature. Weighted correlation network analysis (WGCNA) was used to identify the target genes associated with high-risk characteristics. Gene set enrichment analysis was used to suggest the molecular mechanism of MYBL2 in PC. In addition, in vitro experiments were carried out to validate the role of MYBL2 in PC. Results Ten DNA methylation sites were selected as the prognostic signature. A high expression of MYBL2 was associated with a poor prognosis in PC patients. The effect of MYBL2 in PC was related to KRAS, AKT, IL21, and ATM. MYBL2 facilitates the proliferation, migration, invasion, and metastasis of PC cells. Conclusions We developed a DNA methylation 10-CpG prognostic signature to predict the prognosis of PC patients. And the high expression of MYBL2 in PC may be related to poor prognosis.

EGFR/FOXO3A/LXR-α Axis Promotes Prostate Cancer Proliferation and Metastasis and Dual-Targeting LXR-α/EGFR Shows Synthetic Lethality

Prostate cancer is the second leading cause of cancer-related death in men. Early prostate cancer has a high 5-year survival rate. However, the five-year survival rate is low in progressive prostate cancer, which manifests as bone metastasis. The EGF receptor overexpression increases during disease progression and in the development of castration-resistant disease, and may be a potential therapeutic target. Liver X receptors (LXRs) are ligand-dependent nuclear receptor transcription factors and consist of two subtypes, LXR-α and LXR-β, which can inhibit tumor growth in various cancer cells. We revealed that LXR-α, but not LXR-β, was reduced in prostate cancer tissues compared with adjacent normal tissues. LXRs’ agonist GW3965 enhanced the inhibitory action of LXR-α on the proliferation and metastasis of prostate cancer cells. Furthermore, our results support the notion that LXR-α is regulated by the EGFR/AKT/FOXO3A pathway. As an EGFR inhibitor, Afatinib could weaken AKT activation and increase the expression level of FOXO3A in prostate cancer. In addition, we indicated that the combination of Afatinib and GW3965 simultaneously increased and activated LXR-α, which led to an increase of tumor suppressors, and eventually inhibited tumor progression. Therefore, the combination of EGFR inhibitor and LXRs agonist may become a potential treatment strategy for prostate cancer, especially metastatic prostate cancer.

Overexpression of LINC00852 promotes prostate cancer cell proliferation and metastasis.

Long noncoding RNAs play a key role in the development and progression of various human cancers. Recently, LINC00852 has been reported to be associated with spinal metastasis lung adenocarcinoma. However, the role and potential mechanisms of LINC00852 in prostate cancer cells remain largely unknown. LINC00852 expression in prostate cancer cells was examined by quantitative real-time polymerase chain reaction. Western blotting was used to detect protein expressions in prostate cancer cells. Cell cycle was analyzed by flow cytometric analysis. Cell proliferation was measured by cck-8 assay. The migration and invasion capabilities were determined using transwell assays. In this study, we found that LINC00852 was highly expressed in prostate cancer tissues based on the TCGA database. Overexpression of LINC00852 mediated by lentivirus significantly reinforced the proliferation and colony formation abilities of prostate cancer cell linePC3. The migration and invasion capabilities were also augmented by overexpression of LINC00852. Flow cytometric analysis revealed that LINC00852 overexpression resulted in a decrease of cells in G0/G1 phase. Moreover, overexpression of LINC00852 affected the expression of epithelial-mesenchymal transition-related proteins. Our data collectively demonstrate that LINC00852 contributes to prostate cancer proliferation and metastasis, indicating that LINC00852is a new promising diagnostic and therapeutic target for treatment of prostate cancer.

Abstract 6178: Loss of DAB2IP promotes resistance to radiation in rectal cancer by activating HIF-1α

Abstract Rectal cancer is one of the most common cancers in the United State. It shows that approximately 72.20% of the diagnosed rectal cancers are T3-4N0 or TxN+ from the SEER database. Preoperative radiotherapy has been performed as a prevalent therapy to decrease the local recurrence after total mesorectal excision. However, some patients could not get benefits from the local radiotherapy because of the resistance to radiation. While different expressions of numerous proteins have been found in radiation resistant cancer, the mechanism has been still veiled. Previously, we reported that DAB2IP, a novel member of the Ras GTPase-activating protein family, was down-regulated in various human cancers. DAB2IP functions as a scaffold protein to balance proliferation and apoptosis, and also inhibits metastasis in prostate cancer cells. In CRC, loss of DAB2IP increases the properties of cancer stem cells by regulating the NF-kB signal pathway, which also indicates the poor survival outcome. However, the role and mechanism of DAB2IP involving the resistance to radiation has not been elucidated. In this study, firstly, we compared the expression of DAB2IP in rectal cancers sensitive (42 patients) and non-sensitive (47 patients) to radiation by immunohistochemistry. Our data showed that non- or low-expression of DAB2IP was found in patients resistant to radiation (P<0.001). And these patients had worse disease free survival than high DAB2IP expression patients (p<0.01). Multivariate analyses indicated that DAB2IP expression level was an independently prognostic marker for survival of patients with rectal cancer (p<0.05). Then, we explored the biological function of DAB2IP by knocking down endogenous DAB2IP in cultured rectal cancer cell line SW837. Our results showed that knocking down DAB2IP in SW837 increased the survival rate when exposed to 2Gy dose radiation demonstrated by MTT assay and Anexin V/PI assay in flow cytometery. In xenograft model, SW837 with DAB2IP knocking down grew faster by recording the growth curve even if given total 10Gy dose radiation. Moreover, we found the amount of cleaved PARP and phosphorylated γ-H2AX decreased in DAB2IP knocking down cells exposed to 2Gy dose radiation for 6h. In addition, loss of DAB2IP could promote HIF-1α expression in nucleus and activate the signal pathway by HIF-1α luciferase analysis. In SW837 with DAB2IP knocking down, knocking down the HIF-1a by siRNA could almost rescue DAB2IP loss inducing the resistance to radiation. Taken together, our data provides strong evidence that loss of DAB2IP may contribute to the resistance to radiation in rectal cancer by activating the HIF-1α pathway. Citation Format: Shenglan Yang, Jiang Min, Liang liu, Daxing Xie. Loss of DAB2IP promotes resistance to radiation in rectal cancer by activating HIF-1α [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6178.

Inhibition of TMPRSS2 by HAI-2 reduces prostate cancer cell invasion and metastasis.

TMPRSS2 is an important membrane-anchored serine protease involved in human prostate cancer progression and metastasis. A serine protease physiologically often comes together with a cognate inhibitor for execution of proteolytically biologic function; however, TMPRSS2’s cognate inhibitor is still elusive. To identify the cognate inhibitor of TMPRSS2, in this study, we applied co-immunoprecipitation and LC/MS/MS analysis and isolated hepatocyte growth factor activator inhibitors (HAIs) to be potential inhibitor candidates for TMPRSS2. Moreover, the recombinant HAI-2 proteins exhibited a better inhibitory effect on TMPRSS2 proteolytic activity than HAI-1, and recombinant HAI-2 proteins had a high affinity to form a complex with TMPRSS2. The immunofluorescence images further showed that TMPRSS2 was co-localized to HAI-2. Both KD1 and KD2 domain of HAI-2 showed comparable inhibitory effects on TMPRSS2 proteolytic activity. In addition, HAI-2 overexpression could suppress the induction effect of TMPRSS2 on pro-HGF activation, extracellular matrix degradation and prostate cancer cell invasion. We further determined that the expression levels of TMPRSS2 were inversely correlated with HAI-2 levels during prostate cancer progression. In orthotopic xenograft animal model, TMPRSS2 overexpression promoted prostate cancer metastasis, and HAI-2 overexpression efficiently blocked TMPRSS2-induced metastasis. In summary, the results together indicate that HAI-2 can function as a cognate inhibitor for TMPRSS2 in human prostate cancer cells and may serve as a potential factor to suppress TMPRSS2-mediated malignancy.

Chelerythrine suppresses proliferation and metastasis of human prostate cancer cells via modulating MMP/TIMP/NF-κB system.

Chelerythrine is a natural benzo[c]phenanthridine alkaloid found in many herbs and displays a wide range of antitumor activities. Here, the present study tested their effects on prostate cancer cells. The addition of chelerythrine can significantly inhibit the proliferation of androgen-independent prostate cancer DU145 and PC-3 cells at the concentration of 5 and 10μM, but not on androgen-dependent prostate cancer LNCaP cells as well as normal prostate epithelial cell line PrEC cells. Wound migration and transwell invasion assay showed the similar inhibitory effect of chelerythrine on the migration and invasion of DU145 and PC-3 cells in the same condition. Western blot analysis further confirmed that chelerythrine not only dramatically decreased MMP-2, MMP-9, and uPA protein expression, but also augmented the expression of their endogenous inhibitors (TIMP-1 and TIMP-2) and plasminogen activator inhibitors (PAI-1 and PAI-2) in both cancer cells. Meanwhile, NF-κB and AP-1 transcription factors were all suppressed as evidenced by the decline of p-p65, c-Fos, and c-Jun protein expression in both cells. Taken together, these findings suggested that chelerythrine could reduce the metastasis of androgen-independent prostate cancer cells via modulation of MMP/TIMP system and inactivation of NF-κB pathway.

Snail promotes prostate cancer migration by facilitating SPOP ubiquitination and degradation

Prostate cancer (PCa) is the second leading cause of cancer-associated mortality in men. Speckle-type pox virus and zinc finger protein (SPOP), the most frequently mutated gene in PCa, functions as a tumor suppressor via degradation of cancer-promoting substrates. However, its upstream regulation in PCa metastasis remains poorly determined. Here, in a Snail-induced metastatic PCa model, we observed an accelerated degradation of SPOP protein in cells, which is crucial for the PCa migration and activation of the AKT signaling pathway. Mechanistically, we demonstrated that binding to Snail promoted SPOP ubiquitination and degradation. Moreover, the bric-a-brac/tramtrack/broad complex (BTB) domain of SPOP is turned out to be essential for Snail-mediated SPOP degradation. Thus, our findings reveal a post-translational level regulation of SPOP expression that facilitates the metastasis of PCa cells.