Lijun Mao

SATB1 is overexpressed in metastatic prostate cancer and promotes prostate cancer cell growth and invasion.

BackgroundSpecial AT-rich sequence binding protein 1 (SATB1) is a nuclear factor that functions as the global chromatin organizer to regulate chromatin structure and gene expression gene expression. SATB1 has been shown to be abnormally expressed in various types of cancer. However, the expression and role of SATB1 in prostate cancer remain unclear.Methods120 cases of prostatic carcinoma and 60 cases of benign prostate hyperplasia were analyzed for SATB1 expression by immunohistochemistry. LNCaP, DU-145, and PC3 prostate cancer cells were examined for SATB1 expression by Western blot analysis. Cell proliferation and invasion was evaluated by CCK8 and transwell invasion assay, respectively.ResultsSATB1 staining was stronger in prostatic carcinomas with metastasis than in those without metastasis, but was absent in benign prostate hyperplasia. Furthermore, SATB1 expression was positively correlated with bone metastasis and the Gleason score. SATB1 overexpression promoted the proliferation and invasion of LNCaP cells while SATB1 knockdown inhibited the proliferation and invasion of DU-145 cells.ConclusionsThese findings provide novel insight into oncogenic role of SATB1 in prostate cancer, suggesting that SATB1 is a promising biomarker and therapeutic target for prostate cancer.

Inhibition of renal cancer cell growth by oncolytic adenovirus armed short hairpin RNA targeting hTERT gene

RNA interference (RNAi) has been proved to be a powerful tool for gene knockdown purpose and holds a great promise for the treatment of cancer. Our previous study demonstrated that the reduction of hTERT expression by means of chemically synthesized siRNAs and shRNAs expressed from plasmid resulted in proliferation inhibition in human renal carcinoma cells. In this study, we constructed a novel oncolytic adenovirus-based shRNA expression system, ZD55-hTERT, and to explore ZD55- hTERT–mediated RNAi for hTERT gene silencing. Our results showed that ZD55-hTERT could induce silencing of hTERT gene effectively, allow for efficient tumor-specific viral replication and induce the apoptosis of tumor cells effectively in vitro and in nude mice. We conclude that combining shRNA gene therapy and oncolytic virotherapy can enhance antitumor efficacy as a result of synergism between CRAd oncolysis and shRNA antitumor responses.

Potent antitumor efficacy of interleukin-18 delivered by conditionally replicative adenovirus vector in renal cell carcinoma-bearing nude mice via inhibition of angiogenesis.

It has been demonstrated that interleukin 18 (IL-18) exerts antitumor activity. In this study, we investigated whether oncolytic adenovirus-mediated gene transfer of IL-18 could induce strong antitumor activity. A tumor-selective replicating adenovirus expressing IL-18 (ZD55-IL-18) was constructed by insertion of an IL-18 expression cassette into the ZD55 vector, which is based on deletion of the adenoviral E1B 55-kDa gene. ZD55-IL-18 could express substantially more IL-18 than Ad-IL-18 because of replication of the vector. It has been shown that ZD55-IL-18 exerted a strong cytopathic effect and significant apoptosis in renal cell carcinoma. ZD55-IL-18 significantly decreased VEGF and CD34 expression in the tumor cells. Treatment of established tumors with ZD55-IL-18 showed much stronger antitumor activity than that induced by ZD55-EGFP or Ad-IL-18. These data indicated that oncolytic adenovirus expressing IL-18 could exert potential antitumor activity via inhibition of angiogenesis and offer a novel approach to cancer therapy.

SATB1 promotes prostate cancer metastasis by the regulation of epithelial-mesenchymal transition.

Special AT-rich sequence binding protein 1 (SATB1) plays important role in the regulation of chromatin structure and gene expression. Recent studies have indicated oncogenic role of SATB1. However, the function of SATB1 in prostate cancer progression and metastasis remains unclear. In this study SATB1 expression vector or siRNA was employed to modulate the expression level of SATB1 in prostate cancer cells and xenograft tumor in nude mouse model. Immunohistochemical analysis was performed on clinical prostate cancer samples. Silencing SATB1 inhibited the growth of DU-145 cells subcutaneous tumor in nude mice, while SATB1 overexpression promoted the growth of LNCaP cells subcutaneous tumor in nude mice. Immunohistochemical and Western blot analysis of the xenografts showed that silencing SATB1 led to decreased expression of vimentin and MMP2 and increased expression of E-cadherin, while SATB1 overexpression led to increased expression of vimentin and MMP2 and decreased expression of E-cadherin. Furthermore, SATB1, vimentin and MMP2 expression was increased significantly while E-cadherin expression was reduced significantly in clinical samples of prostate carcinoma with metastasis compared to prostate carcinoma without metastasis and benign prostate hyperplasia. Taken together, these findings suggest that the modulation of epithelial-mesenchymal transition by SATB1 may contribute to prostate cancer metastasis.

Oncolytic virus carrying shRNA targeting SATB1 inhibits prostate cancer growth and metastasis

Recent studies suggest that SATB1 is a promising therapeutic target for prostate cancer. To develop novel SATB1-based therapeutic agents for prostate cancer, in this study, we aimed to construct ZD55-SATB1, an oncolytic adenovirus ZD55 carrying shRNA targeting SATB1, and investigate its effects on the inhibition of prostate cancer growth and metastasis. ZD55-SATB1 was constructed and used to infect human prostate cancer cell lines DU145 and LNCaP. The inhibitory effect of ZD55-SATB1 on SATB1 expression was evaluated by reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis. The cytotoxicity of ZD55-SATB1 was detected by MTT assay. Cell invasion was detected by Matrigel invasion assay. The in vivo antitumor activities of ZD55-SATB1 were evaluated in xenograft mouse model. We found that ZD55-SATB1 selectively replicated and significantly reduced SATB1 expression in DU145 and LNCaP cells. ZD55-SATB1 effectively inhibited the viability and invasion of DU145 and LNCaP cells in vitro and inhibited prostate cancer growth and metastasis in xenograft nude mice. In conclusion, replicative oncolytic adenovirus armed with SATB1 shRNA exhibits effective antitumor effect in human prostate cancer. Our study provides the basis for the development of ZD55-SATB1 for the treatment of prostate cancer.

Relationships among MTHFR a1298c Gene Polymorphisms and Methylation Status of Dact1 Gene in Transitional Cell Carcinomas

OBJECTIVES The purpose of this study was to determine the relationship between methylation status of the Dact1 gene and MTHFR a1298c polymorphic forms in transitional cell carcinoma tissues in a Chinese population. METHODS Polymorphisms of folate metabolism enzyme gene MTHFR were assessed by restrictive fragment length polymorphism (RFLP) methods and PCR-based DNA methylation analysis was used to determine the CpG island methylation status of the Dact1 gene. Associations between the methylation status of the Dact1 gene and clinical characteristics, as well as MTHFR a1298c polymorphisms, were analyzed. RESULTS aberrant methylation of the Dact1 gene was found in 68.3% of cancer tissues and 12.4% of normal tissues,. The methylation rate of the Dact1 gene in cancer tissues was significantly higher in patients with lymph node metastasis than in those without lymph node metastasis (46.3% vs. 17.2%, P = 0.018). No association was found between aberrant DNA methylation and selected factors including sex, age, tobacco smoking, alcohol consumption and green tea consumption. After adjusting for potential confounding variables, variant allele of MTHFR a1298c was found to be associated with methylation of the Dact1 gene. Compared with wild type CC, the odds ratio was 4.33 (95% CI: 1.06-10.59) for AC and 4.95 (95% CI: 1.18-12.74) for AA. The N stage in TNM staging and the occurrence of lymph node metastasis were associated with an MTHFR 1298 AAμAC genotype (P<0.05). CONCLUSION MTHFR 1298 AC and AA genotypes might help maintain a normal methylation status of the Dact1 gene, aberrant CpG island methylation of which is closely related to the genesis and progression of transitional cell carcinoma.

Ki67 targeted strategies for cancer therapy

Ki67 is a well-known proliferation marker for the evaluation of cell proliferation. Numerous studies have indicated that Ki67 index independently predicts cancer progression. Moreover, because Ki67 is highly expressed in malignant cells but almost could not be detected in normal cells, it has become a promising target for cancer therapy. In this review, we summarize recent advances in Ki67 targeted cancer therapy. In particular, we highlight recent development on the exploitation of Ki67 promoter to drive the expression of siRNAs or therapeutic genes in cancer cells specifically. The use of Ki67 as an attractive target opens a new avenue for cancer therapy.

Replication-competent adenovirus expressing TRAIL synergistically potentiates the antitumor effect of gemcitabine in bladder cancer cells

Replication-competent adenovirus armed with therapeutic tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) gene has been shown to sensitize cancer cells to chemotherapy and radiotherapy. However, the synergistic antitumor effect of replication-competent adenovirus expressing TRAIL and the cytotoxic chemotherapy in bladder cancer remains to be determined. Bladder cancer T24 cells or mouse tumor xenografts were infected with replication-competent adenovirus armed with human TRAIL (ZD55-TRAIL) alone or in combination with gemcitabine. The mRNA and protein levels of TRAIL were determined by “Reverse transcription polymerase chain reaction” and Western blotting, respectively. Cell viability was tested by CCK8 assay. Tumor growth in the mice was monitored every week by measuring tumor size. Cell apoptosis was detected by Annexin V-FITC staining and TUNEL assay. We found that adenovirus ZD55-TRAIL efficiently replicated both in cultured bladder cancer T24 cells and T24 mouse tumor xenograft as demonstrated by the overexpression of TRAIL and E1A. Gemcitabine did not affect the expression of TRAIL. In cultured T24 cells, ZD55-TRAIL enhanced the growth inhibitory effects of gemcitabine, accompanied by increased apoptosis. Similarly, ZD55-TRAIL synergistically enhanced the antitumor effect and induction of apoptosis following gemcitabine treatment in mouse T24 xenografts. In conclusion, replicative adenovirus armed with TRAIL synergistically potentiates the antitumor effect of gemcitabine in human bladder cancer. Our study provides the basis for the development of ZD55-TRAIL in combination with conventional chemotherapy for the treatment of bladder cancer.

Oncological Outcome of Primary and Secondary Muscle-Invasive Bladder Cancer: A Systematic Review and Meta-analysis.

Conflicting results of survival outcomes for primary and secondary muscle-invasive bladder cancer (MIBC) have been reported in previous studies. Primary MIBC is defined as presentation of muscle-invasive disease at initial diagnosis while secondary MIBC presumes that non-muscle invasive disease later progressed to MIBC. Due to the varying reports, we conducted a systematic review and meta-analysis to compare survival outcomes between the two groups. Relevant studies were retrieved from Medline, Embase, the Cochrane Library, and Scopus using a comprehensive search approach. Cancer-specific survival (CSS) was the outcome measure. A total of 14 studies involving 4,075 cases were included. Patients with secondary MIBC were significantly correlated with worse CSS in model I (pooled HR: 1.29, 95% CI: 1.07–1.56, P = 0.008). The results of sensitivity analyses indicated that the omission of any single study each time did not have a significant impact on the combined risk estimates. Egger’s test suggested no publication bias among these studies. The European Organization for Research and Treatment of Cancer (EORTC) risk score offers the possibility of stratifying the secondary MIBC patients into different risk groups. In high-risk NMIBC, timely radical cystectomy should be considered. Further study is required to assess the multimodal therapy in both high-risk NMIBC and secondary MIBC patients as well as to evaluate genetic and molecular drivers of tumor induction, promotion, and progression.