Suppression of LIM and SH3 Domain Protein 1 (LASP1) Negatively Regulated by Androgen Receptor Delays Castration Resistant Prostate Cancer Progression.

LIM and SH3 domain protein 1 (LASP1) has been implicated in several human malignancies and has been shown to predict PSA recurrence in prostate cancer. However, the anti-tumor effect of LASP1 knockdown and the association between LASP1 and the androgen receptor (AR) remains unclear. The aim of this study is to clarify the significance of LASP1 as a target for prostate cancer, and to test the effect of silencing LASP1 in vivo using antisense oligonucleotides (ASO). A tissue microarray (TMA) was performed to characterize the differences in LASP1 expression in prostate cancer treated after hormone deprivation therapy. Flow cytometry was used to analyze cell cycle. We designed LASP1 ASO for knockdown of LASP1 in vivo studies. The expression of LASP1 in TMA was increased after androgen ablation and persisted in castration resistant prostate cancer (CRPC). Also in TMA, compared with LNCaP cell, LASP1 expression is elevated in CRPC cell lines (C4-2 and VehA cells). Interestingly, suppression of AR elevated LASP1 expression conversely, AR activation decreased LASP1 expression. Silencing of LASP1 reduced cell growth through G1 arrest which was accompanied by a decrease of cyclin D1. Forced overexpression of LASP1 promoted cell cycle and induced cell growth which was accompanied by an increase of cyclin D1. Systemic administration of LASP1 ASO with athymic mice significantly inhibited tumor growth in CRPC xenografts. These results indicate that LASP1 is negatively regulated by AR at the transcriptional level and promotes tumor growth through induction of cell cycle, ultimately suggesting that LASP1 may be a potential target in prostate cancer treatment. Prostate 77:309-320, 2017. © 2016 Wiley Periodicals, Inc.

Dejima T ，Imada K ，Takeuchi A ，Shiota M ，Leong J ，Tombe T ，Tam K ，Fazli L ，Naito S ，Gleave ME ，Ong CJ ... -  《-》

PDLIM2 suppression efficiently reduces tumor growth and invasiveness of human castration-resistant prostate cancer-like cells.

Although PDLIM2 gene may have a context-dependent role in various human malignancies and can be a potential therapeutic target, only a limited number of in vitro studies addressed the molecular functions of PDLIM2 in prostate cancer. Here, we aimed to explore the role of PDLIM2 and the effect of the PDLIM2 gene suppression on oncogenic phenotypes of human castration-resistant prostate cancer (CRPC)-like cells. We used human CRPC-like cell lines (PC3, DU145, and C4-2B) for our experiments. Transcription levels of PDLIM2 and relevant genes were measured by real time-PCR and protein expression was analyzed by western blot. Cell viability, proliferation, clonogenic growth, and tumor sphere formation were examined after a specific inhibition of PDLIM2 using RNA interference. Flow cytometry was used to examine apoptotic cell death and cell cycle disturbances. Wound healing and transwell migration assays were performed to investigate the invasion capabilities of CRPC-like cells. Additionally, key oncogenic signaling pathways were examined using western blot. Lastly, we evaluated the in vivo efficacy of PDLIM2 suppression on tumor growth of human CRPC xenografts in mice. We observed a significant enhancement of PDLIM2 expression in human CRPC-like cell lines, while a specific inhibition of PDLIM2 reduced cell viability and proliferation due to apoptotic cell death. Conversely, PDLIM2 overexpression significantly reduced cell proliferation compared to the negative control in androgen-sensitive LNCaP cells. Moreover, PDLIM2 suppression led to a decrease of clonogenic growth and tumor sphere formation in three-dimensional cultures with the G2/M cell cycle arrest in human CRPC-like cells. PDLIM2 inhibition also attenuated cellular migration and invasion capabilities of human CRPC-like cells, and reduced the expression of mesenchymal marker. Among several oncogenic signaling pathways, only the MAPK/ERK signaling cascade was decreased by PDLIM2 inhibition and reciprocally, ERK inhibition down-regulated PDLIM2 expression. Importantly, PDLIM2 inhibition remarkably compromised tumor growth in a human CRPC xenograft model. In summary, the suppression of PDLIM2 significantly reduced such oncogenic phenotypes as proliferation, clonogenicity, invasiveness, and tumor cell growth in human CRPC-like cells both in vitro and in vivo, indicating that PDLIM2 may be considered a novel therapeutic target gene for treating human CRPC.

Kang M ，Lee KH ，Lee HS ，Park YH ，Jeong CW ，Ku JH ，Kim HH ，Kwak C ... -  《-》

LIM and SH3 protein 1 regulates cell growth and chemosensitivity of human glioblastoma via the PI3K/AKT pathway.

Zhong C ，Chen Y ，Tao B ，Peng L ，Peng T ，Yang X ，Xia X ，Chen L ... -  《BMC CANCER》

Increased long noncoding RNA LASP1-AS is critical for hepatocellular carcinoma tumorigenesis via upregulating LASP1.

Aberrant long noncoding RNAs (lncRNA) have been proved to be associated with the many types of malignant tumors (including hepatocellular carcinoma [HCC]). In this study, a lncRNAs and mRNAs microarray analysis was performed in three pairs of HCC patitents' tumor. We found lncRNA LIM and SH3 protein 1 antisense (LASP1-AS) and its sense-cognate gene LIM and SH3 protein 1 (LASP1) were upregulated in HCC and both are correlated with poorer prognosis and lower survival of HCC patients. Meanwhile, the expression of LASP1-AS correlated positively with LASP1 expression in HCC tissues. LASP1-AS promoted the proliferation, migration, and invasion abilities of HCC in vitro and vivo by enhancing LASP1 expression. Our study explored lncRNA LASP1-AS as an oncogene in HCC and promoted proliferation and metastasis capabilities of HCC via increasing the expression of its sense-cognate gene LASP1. LncRNA LASP1-AS might be a potential valuable prognostic biomarker and potential therapeutic target of HCC.

Yin L ，Chen Y ，Zhou Y ，Deng G ，Han Y ，Guo C ，Li Y ，Zeng S ，Shen H ... -  《-》

Differential expression of androgen receptor variants in hormone-sensitive prostate cancer xenografts, castration-resistant sublines, and patient specimens according to the treatment sequence.

Androgen receptor variants (AR-vs), especially AR-v7 and AR-v 5, 6, and 7 exon-skipped (AR-v567es), are reportedly key players in the development of castration-resistant prostate cancer (CRPC). We previously established a mouse xenograft model (JDCaP) from a metastatic skin lesion from a Japanese patient with CRPC and that was revealed to exhibit androgen sensitivity. In the present study, we established multiple castration-resistant xenograft models from JDCaP mice to investigate the biological features of CRPC. Tissue from JDCaP mice was transplanted into male and female nude mice, and after serial passaging, castration-resistant sublines (JDCaP-CR2M and JDCaP-CR4M in male mice, JDCaP-CR2F and JDCaP-CR4F in female mice) were established. We investigated anti-androgen and testosterone sensitivity and the messenger RNA expression pattern of full-length AR and AR-vs. In addition, we compared AR protein levels of patient specimens among primary, local-recurrent, and two skin-metastatic tumors. All JDCaP-CR sublines showed continuous growth following the administration of bicalutamide, although the effects of testosterone varied among sublines. Parental JDCaP and JDCaP-CR2M, JDCaP-CR4M, and JDCaP-CR4F sublines expressed AR-v7, whereas JDCaP-CR2F exhibited elevated AR-v567es expression resulting from genomic deletion, which was confirmed by DNA sequencing. Moreover, we confirmed AR-v7 expression in the tumor of the original patient after androgen-deprivation therapy. Each JDCaP-CR subline showed different AR-v-expression patterns, with JDCaP-CR2F expressing AR-v567es due to genomic deletion. Our results indicated that AR-vs emerged after androgen-deprivation therapy and appeared essential for acquisition of castration resistance.

Honda M ，Kimura T ，Kamata Y ，Tashiro K ，Kimura S ，Koike Y ，Sato S ，Yorozu T ，Furusato B ，Takahashi H ，Kiyota H ，Egawa S ... -  《-》