Jirong Wang

Prognostic significance of serum miRNA-21 expression in human non-small cell lung cancer.

Deregulation of microRNAs (miRNAs) plays important roles in tumor progression. The aim of this study was to investigate miR‐21 expression in serum of non‐small cell lung cancer (NSCLC) and its correlation with prognosis of NSCLC patients.

Functional and biological analysis of Bcl-xL expression in human osteosarcoma

Bcl-xL, a member of Bcl-2 protein family functioned as dominant regulators of apoptotic cell death, has been reported to play important roles in malignant transformation and tumor development. In the present study, our aim was to explore the roles of Bcl-xL overexpression and determine its possibility as a therapeutic target in human osteosarcoma. Real-time quantitative RT-PCR and Western blot or immunohistochemistry assays were performed to detect the expression of Bcl-xL mRNA and protein in human osteosarcoma cell lines or tissue samples. The expression of other Bcl-2 family proteins (Bcl-2, Mcl-1, Bim and Bik) in osteosarcoma tissues was also detected by immunohistochemistry. The associations of Bcl-xL mRNA expression with clinicopathologic factors and prognosis of osteosarcoma patients were evaluated. RNA interference or gene overexpression technologies were employed to downregulate or upregulate endogenous Bcl-xL expression in osteosarcoma cells and the effects of Bcl-xL downregulation or upregulation on phenotypes and chemo- or radiosensitivity of human osteosarcoma cells were analyzed. Finally, the mechanism of synergistic effects of Bcl-xL downregulation and chemo- or radiotherapy was explored by detecting the activity of caspase-3. The expression levels of Bcl-xL mRNA and protein in high metastatic osteosarcoma cells showed higher than those in low metastatic osteosarcoma cells. Moreover, the levels of Bcl-xL mRNA expression were significantly higher in osteosarcoma tissues than those in chondroma or corresponding non-tumor tissues (P<0.01), and osteosarcoma tissues showed stronger immunostaining of Bcl-xL protein than non-tumor tissues. The stronger staining of Bcl-2 and Mcl-1 proteins was also observed, while the staining of pro-apoptotic proteins (Bim and Bik) was significantly weaker or not detected in osteosarcoma tissues. The higher levels of Bcl-xL mRNA expression were significantly correlated with advanced clinical stage (P=0.005) or hematogenous metastasis (P=0.001) of osteosarcoma patients. Osteosarcoma patients with higher Bcl-xL mRNA expression showed a poorer survival compared with those with lower expression (P=0.039). Bcl-xL downregulation or upregulation could significantly reduce or increase the proliferation capacity of osteosarcoma cells. Furthermore, Bcl-xL downregulation could significantly enhance in vitro chemo- or radiosensitivity of osteosarcoma cells, which might be associated with elevated activity of caspase-3. Taken together, overexpression of Bcl-xL may play important roles in osteosarcoma progression and this molecule will be a potential chemo- or radiotherapeutic molecular target for osteosarcoma therapy.

Downregulated Long Noncoding RNA BANCR Promotes the Proliferation of Colorectal Cancer Cells via Downregualtion of p21 Expression

BRAF activated non-coding RNA (BANCR), a long non-coding RNA (lncRNA), is crucial for cell migration in melanoma cells and non-small cell lung cancer (NSCLC) cells. However, little is known regarding the role of this gene in the proliferation of colorectal cancer. Therefore, we investigated the involvement of BANCR in the proliferation of colorectal cancer cells. In this study, we show that BANCR expression was significantly down-regulated in colorectal cancer tissues compared with normal tissues, and overexpression of BANCR suppressed colorectal cancer cell growth in vitro and in vivo. We also determined that pCDNA-BANCR-mediated colorectal cancer cell proliferation was associated with induction of G0/G1 cell-cycle arrest and apoptosis enhancement through regulation of p21, and its effects were most likely posttranscriptional. Taken together, our findings suggest that down-regulation of BANCR contributes to the proliferation of colorectal cancer cells, at least in part, through the regulation of p21 protein.

Long non-coding RNA Loc554202 induces apoptosis in colorectal cancer cells via the caspase cleavage cascades

BackgroundAberrant expression of long noncoding RNAs (lncRNAs) has frequently been reported in cancer studies, including those of colorectal cancer (CRC). Increasing evidence suggests that lncRNAs are significantly correlated with the pathogenesis, development and metastasis of cancer. Loc554202 is a 2166-bp transcript on human chromosome 9p21.3, the expression of which is dysregulated in breast and lung cancer cells. However, its role in CRC remains under investigation.MethodsQuantitative real-time polymerase chain reaction (qRT-PCR) was carried out to assess the relative expression of Loc554202 in CRC cell lines and tissues. Gain and/or loss of function approaches were used to investigate the potential functional roles in cell proliferation and apoptosis in vitro and in vivo. qRT-PCR, western-blotting and immunohistochemistry were used to evaluate the mRNA and protein expression of apoptosis-related factors.ResultsLoc554202 was significantly downregulated in cancerous tissues and CRC cell lines compared with adjacent normal tissue and a normal human intestinal epithelial cell line. Low Loc554202 expression was closely associated with advanced pathologic stage and a larger tumor size. The overexpression of Loc554202 decreased the cell proliferation and induced apoptosis in vitro and hindered tumorigenesis in vivo. Loc554202 regulated cell apoptosis partly through the activation of specific caspase cleavage cascades.ConclusionOur results suggest that Loc554202 may play an important role in the progression of CRC and could be a candidate prognostic biomarker or a target for new cancer therapies.

The long noncoding RNA HOXA transcript at the distal tip promotes colorectal cancer growth partially via silencing of p21 expression

Accumulating evidence strongly suggests that dysregulation of long noncoding RNAs (lncRNAs) is associated with human carcinogenesis. The lncRNA HOXA transcript at the distal tip (HOTTIP) is involved in the development of several cancers. However, the biological role of HOTTIP in colorectal cancer (CRC) has not yet been discussed. Here, we report that HOTTIP acts as a functional oncogene in the pathogenesis of CRC. In this study, quantitative polymerase chain reaction (qPCR) was performed to detect the expression of HOTTIP in 48 pairs of colorectal cancer samples. We found that overexpression of HOTTIP is correlated with an advanced pathological stage and a larger tumor size. Moreover, functional analyses revealed that the knockdown of HOTTIP expression by small interfering RNA (siRNA) or small hairpin RNA (shRNA) could inhibit cell proliferation and induce cell apoptosis. More importantly, we observed that HOTTIP knockdown induced a marked increase in the number of cells in the G0/G1 phase and a reduction in the number of cells in the S phase in both DLD-1 cells and SW480 cells. An in vivo experiment also revealed that the knockdown of HOTTIP inhibited tumor growth. Western blot and immunohistochemistry analyses indicated that HOTTIP potentially contributed to CRC cell growth partially through the silencing of p21 expression. Collectively, our results suggest that HOTTIP is involved in the progression of CRC and may provide evidence for HOTTIP being a target for therapy of this disease.

Gambogenic Acid Induction of Apoptosis in a Breast Cancer Cell Line

BACKGROUND Gambogenic acid is a major active compound of gamboge which exudes from the Garcinia hanburyi tree. Gambogenic acid anti-cancer activity in vitro has been reported in several studies, including an A549 nude mouse model. However, the mechanisms of action remain unclear. METHODS We used nude mouse models to detect the effect of gambogenic acid on breast tumors, analyzing expression of apoptosis-related proteins in vivo by Western blotting. Effects on cell proliferation, apoptosis and apoptosis-related proteins in MDA-MB-231 cells were detected by MTT, flow cytometry and Western blotting. Inhibitors of caspase-3,-8,-9 were also used to detect effects on caspase family members. RESULTS We found that gambogenic acid suppressed breast tumor growth in vivo, in association with increased expression of Fas and cleaved caspase-3,-8,-9 and bax, as well as decrease in the anti-apoptotic protein bcl-2. Gambogenic acid inhibited cell proliferation and induced cell apoptosis in a concentration-dependent manner. CONCLUSION Our observations suggested that Gambogenic acid suppressed breast cancer MDA-MB-231 cell growth by mediating apoptosis through death receptor and mitochondrial pathways in vivo and in vitro.

Curdione Inhibits Proliferation of MCF-7 Cells by Inducing Apoptosis

BACKGROUND Curdione, one of the major components of Curcuma zedoaria, has been reported to possess various biological activities. It thus might be a candidate anti-flammatory and cancer chemopreventive agent. However, the precise molecular mechanisms of action of curdione on cancer cells are still unclear. In this study, we investigated the effect of curdione on breast cancer. MATERIALS AND METHODS Xenograft nude mice were used to detect the effect of curdione on breast cancer in vivo; we also tested the effect of curdione on breast cancer in vitro by MTT, Flow cytometry, JC-I assay, and western blot. RESULTS Firstly, we found that curdione significantly suppressed tumor growth in a xenograft nude mouse breast tumor model in a dose-dependent manner. In addition, curdione treatment inhibited cell proliferation and induced cell apoptosis. Moreover, after curdione treatment, increase of impaired mitochondrial membrane potential occurred in a concentration dependent manner. Furthermore, the expression of apoptosis-related proteins including cleaved caspase-3, caspase-9 and Bax was increased in curdione treatment groups, while the expression of the anti-apoptotic Bcl-2 was decreased. Inhibitors of caspase-3 were used to confirm that curdione induced apoptosis. CONCLUSIONS Overall, our observations first suggested that curdione inhibited the proliferation of breast cancer cells by inducing apoptosis. These results might provide some molecular basis for the anti-cancer activity of curdione.

Chemopreventive Effect of Dietary Glutamineon Colitis-Associated Colorectal Cancer Is Associated with Modulation of the DEPTOR/mTOR Signaling Pathway

Glutamine plays a protective role in colitis and colitis-associated colorectal cancer (CAC); however, the protective mechanisms are largely unknown to date. DEP domain-containing mTOR-interacting protein (DEPTOR)/mammalian Target of Rapamycin (mTOR) signaling plays an important role in carcinogenesis. The present study investigated the potential molecular mechanisms for the protective effect of glutamine in a murine model of azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced CAC. The effects of glutamine on DEPTOR/mTOR signaling and protein light chain 3 (LC3) were evaluated. Administration of glutamine was associated with attenuated development of CAC. Increased expression of DEPTOR and decreased expressions of factors of mTOR signaling, including phospho-mTOR, phospho-STAT3, phospho-Akt, and phospho-S6, were observed in AOM/DSS mice administered glutamine. Furthermore, oral glutamine was associated with increased LC3-II expression in AOM/DSS mice. The present study indicates that regulation of DEPTOR/mTOR signaling may be an important mechanism for glutamine in prevention against the development of CAC. In addition, the chemopreventive effect of dietary glutamine on CAC is, at least in part, associated with the induction of autophagy.

The association between serum lipids and colorectal neoplasm: a systemic review and meta-analysis

OBJECTIVE There have been inconsistent results published regarding the relationship between dyslipidaemia and an increased risk of colorectal neoplasia (CRN), including colorectal adenoma (CRA) and colorectal cancer (CRC). We conducted a meta-analysis to explore the relationship between dyslipidaemia and CRN. DESIGN We identified studies by performing a literature search using PubMed, EMBASE and the Science Citation Index through October 2013. SETTING We analysed thirty-three independent studies reporting the association between CRN and at least one of the selected lipid components, including total cholesterol (TC), TAG, HDL-cholesterol (HDL-C) and LDL-cholesterol (LDL-C). SUBJECTS CRN cases (n 21 809) were identified. RESULTS Overall, people with high levels of serum TAG (risk ratio (RR)=1.08; 95% CI 1.05, 1.12, P<0.00001) and LDL-C (RR=1.07; 95% CI 1.00, 1.14, P=0.04) presented an increased prevalence of CRN. Subgroup analyses revealed that high levels of serum TC (RR=1.04; 95% CI 1.01, 1.09, P=0.02), TAG (RR=1.06; 95% CI 1.03, 1.10, P=0.0009) and LDL-C (RR=1.11; 95% CI 1.04, 1.19, P=0.003) increased the risk of CRA but not of CRC. No association between serum HDL-C and risk for CRN (including CRA and CRC) was observed. CONCLUSIONS Both TAG and LDL-C were significantly associated with an increasing prevalence of CRN. High levels of serum TC, TAG and LDL-C were positively associated with CRA but not with CRC. No significant association was observed between levels of serum HDL-C and CRN.

A variant (rs932335) in the HSD11B1 gene is associated with colorectal cancer in a Chinese population

Glucocorticoid hormones have been reported to contribute to the regulation of cellular proliferation and differentiation and to inhibit the growth of cells in several colon tumors and adenocarcinoma cell lines. As a regulator of glucocorticoid levels, type I isoform HSD11B1 is a bidirectional enzyme but acts predominantly as an oxidoreductase to yield active glucocorticoids, cortisol or corticosterone. To date, studies investigating the associations between the polymorphisms of HSD11B1 and the risk for cancer have shown inconclusive results. In our study, we aimed to investigate whether the polymorphisms of HSD11B1 may influence the genetic susceptibility to colorectal cancer (CRC) in a Chinese population. Four single-nucleotide polymorphisms of HSD11B1 (rs846910 G/A, rs11807619 G/T, rs932335 C/G, and rs13306421 G/A) were detected using a PCR-ligase detection reaction in a case–control study comprising 110 CRC patients and 118 controls. Logistic regression was used to evaluate genetic associations with the occurrence of CRC. Real-time PCR was used to test the mRNA expression of HSD11B1 in 18 CRC tissues. The frequencies of the rs932335 GC genotype were significantly higher among the patients compared with controls (P=0.019). Compared with individuals carrying the GG genotype, individuals with the GC/CC genotype had a significantly increased susceptibility to CRC occurrence (odds ratio=2.23, 95% confidence interval=1.27–3.94, P=0.008). In cancer tissues, patients carrying the GG genotype also displayed an increased mRNA level of HSD11B1 (P=0.019). These results suggested that the HSD11B1 rs932335 G/C polymorphism had an effect on CRC occurrence. These findings also suggest that the functional polymorphism rs932335 in intron4 of HSD11B1 may influence the susceptibility to and progression of CRC in a Chinese population. Large population-based prospective studies are required to validate our findings.