Yongmei Yang

MiR-429 is an independent prognostic factor in colorectal cancer and exerts its anti-apoptotic function by targeting SOX2

Emerging evidence has demonstrated that microRNAs (miRNAs) can act as oncogenes or tumor suppressors to participate in cancer development. In this study, we found that miR-429 expression was up-regulated in human colorectal cancer (CRC) tissues, and the high miR-429 expression was significantly associated with tumor size, lymph node metastasis and poor prognosis. Functionally, miR-429 overexpression suppressed cell apoptosis by directly targeting SOX2 in HT-29 cells. Taken together, our data suggest for the first time that miR-429 could play an oncogenic role in the cellular processes of CRC and represent a novel prognostic biomarker for CRC.

Sox2 nuclear expression is closely associated with poor prognosis in patients with histologically node-negative oral tongue squamous cell carcinoma

Sox2 is a marker of embryonic stem cell pluripotency and plays an important role in tumor progression. However, Sox2 expression in oral tongue squamous cell carcinoma (OTSCC) and its correlation with patients prognosis have not been investigated so far. In this study, we detected the expression of Sox2 in 82 patients with histologically node-negative (pN0) OTSCC by immunohistochemistry, and evaluated its correlation with clinicopatologic factors and disease prognosis. Sox2 positive expression was detected in 62.2% patients and showed a significant association with large tumor size. Survival analysis showed that patients with Sox2 positive expression had significantly poorer overall, cancer-specific and disease-free survivals than those with Sox2 negative expression at 5years after operation (P=0.004, 0.004 and 0.001, respectively). Multivariate analysis demonstrated that Sox2 positive expression was an independent prognosticator of unfavorable overall, cancer-specific and disease-free survivals (P=0.032, 0.035 and 0.011, respectively). According to our results, Sox2 positive expression was frequent in pN0 OTSCC and involved in tumor progression. The measurement of Sox2 expression may be helpful in predicting relapse and prognosis of patients with pN0 OTSCC.

Up-regulation of miR-182 expression in colorectal cancer tissues and its prognostic value.

PurposeAccumulating evidences indicate that dysregulated microRNAs (miRNA) are involved in cancer tumorigenesis and progression. In the present study, we evaluated the expression of miR-182 in colorectal cancer and adjacent noncancerous tissues and explored its associations with clinicopathological characteristics and prognosis.MethodsQuantitative real-time PCR was used to analyze the expression of miR-182 in 148 pairs of colorectal cancer and adjacent noncancerous tissues. The relationship between miR-182 expression and clinicopathological characteristics in colorectal cancer tissues was estimated using Mann–Whitney U test or Kruskal–Wallis test, as appropriate. We calculated the survival curves and prognostic values of each variable by the Kaplan–Meier method and Cox proportional hazards regression analysis, respectively.ResultsThe expression of miR-182 was found up-regulated in colorectal cancer tissues compared with adjacent noncancerous tissues (pu2009<u20090.001), and its up-regulation was significantly correlated with large tumor size (pu2009=u20090.016), positive regional lymph node metastasis (pu2009=u20090.008), and advanced tumor–node–metastasis stage (pu2009=u20090.020). Furthermore, Kaplan–Meier analysis demonstrated that high miR-182 expression predicted poor survival (pu2009=u20090.001), and Cox proportional hazards risk analysis indicated that miR-182 was an independent prognostic factor for colorectal cancer.ConclusionsMiR-182 was up-regulated in colorectal cancer tissues and correlated with adverse clinical characteristics and poor prognosis, indicating that miR-182 might be involved in colorectal cancer progression and could be used as a potential prognostic biomarker and therapeutic target in the management of colorectal cancer.

Hypoxia induces T-cell apoptosis by inhibiting chemokine C receptor 7 expression: the role of adenosine receptor A(2).

Hypoxia is a major characteristic of the tumor microenvironment, and its effects on immune cells are proposed to be important factors for the process of tumor immune escape. It has been reported that hypoxia affects the function of dendritic cells and the antitumor function of T cells. Here we discuss the effects of hypoxia on T-cell survival. Our results showed that hypoxia induced apoptosis of T cells. Adenosine and adenosine receptors (AR) are important to the hypoxia-related signaling pathway. Using AR agonists and antagonists, we demonstrated that hypoxia-induced apoptosis of T cells was mediated by A2a and A2b receptors. Furthermore, we are the first, to our knowledge, to report that hypoxia significantly inhibited the expression of chemokine C receptor 7 (CCR7) of T cells via the A2R signal pathway, perhaps representing a mechanism of hypoxia-induced apoptosis of T cells. Collectively, our research demonstrated that hypoxia induces T-cell apoptosis by the A2R signaling pathway partly by suppressing CCR7. Blocking the A2R signaling pathway and/or activation of CCR7 can increase the anti-apoptosis function of T cells and may become a new strategy to improve antitumor potential.

Regulation of Th1/Th2 polarization by tissue inhibitor of metalloproteinase-3 via modulating dendritic cells

Tissue inhibitor of metalloproteinase-3 (TIMP-3) is one of a family of proteins inhibiting matrix metalloproteinases, which has also been identified as a mediator for checking inflammation. Meanwhile, it is well known that inflammation causes the activation of the immune response. However, it is not clear whether TIMP-3 plays a role in the immune system. In the present study, we demonstrated a novel function of TIMP-3 in Th1/Th2 polarization through its influence on the antigen-presenting cells. First, TIMP-3 was found strikingly up-regulated by IL-4 during the differentiation of human dendritic cells via the p38MAPK pathway. Second, the expression of costimulatory molecule-CD86 was repressed by TIMP-3. Besides, the induction of IL-12 in matured dendritic cells was significantly inhibited in a PI3K-dependent manner. Furthermore, dendritic cells matured in the presence of TIMP-3 could stimulate allogeneic naive T helper (Th) cells to display a prominent Th2 polarization. Importantly, in an autoimmune disorder-primary immune thrombocytopenia, TIMP-3 showed a statistically positive correlation with IL-4 and platelet count, but a negative correlation with IFN-γ in patient blood samples. Collectively, these in vitro and in vivo data clearly suggested a novel role of TIMP-3 in Th1/Th2 balance in humans.

Urinary cell-free microRNA-106b as a novel biomarker for detection of bladder cancer

Cell-free microRNAs (miRNAs) stably and abundantly exist in body fluids and emerging evidence suggests cell-free miRNAs as a novel class of noninvasive disease biomarkers. In this study, we hypothesized that the quantitative detection of the oncogenic miR-106b-25 cluster in urine could be a useful clinical biomarker for bladder cancer (BCa). Three members of the miR-106b-25 cluster (miR-106b, miR-93 and miR-25) were quantified by real-time RT-PCR in urine supernatant of 112 BCa patients and 78 age-matched controls. In our study, the urinary levels of miR-106b were significantly higher in BCa patients than controls (Pxa0<xa00.001). No significant difference was observed in the urinary levels of miR-93 and miR-25 between two groups. Furthermore, the levels of urinary miR-106b were significantly reduced in postoperative samples compared with the levels in the preoperative samples (Pxa0=xa00.007). With respect of clinicopathological characteristics, the level of urinary miR-106b was associated with advanced tumor stage. Receiver operating characteristic (ROC) analysis revealed that urinary miR-106b had considerable diagnostic accuracy, yielding an AUC (the areas under the ROC curve) of 0.802 with 76.8xa0% sensitivity and 72.4xa0% specificity in differentiating BCa from controls. In conclusion, our data indicate that urinary cell-free miR-106b might provide new complementary tumor biomarkers for BCa.

Aberrant expression of circulating Th17, Th1 and Tc1 cells in patients with active and inactive ulcerative colitis

Ulcerative colitis (UC) is a chronic relapsing inflammatory bowel disease, yet its etiology and pathogenesis remain poorly understood. The aberrant expression of T lymphocytes plays an essential role in the progression of UC. This study aimed to evaluate the expression profile of circulating Th17, Th1 and Tc1 cells in patients with active and inactive UC. Our results revealed that the percentage of circulating Th17 cells (CD3+CD8-IL-17+) was significantly increased in patients with active UC when compared with the percentage in patients with inactive UC, Crohns disease (CD) and healthy controls. The percentages of circulating Th1 (CD3+CD8-IFN-γ+) and Tc1 (CD3+CD8+IFN-γ+) cells were also higher in patients with active UC when compared with the percentages in patients with inactive UC and normal controls, although levels were lower than that in CD. Further analysis showed that Th17 cells were positively correlated with Th1 cells, but not with Tc1 cells. Notably, the three cells had a positive correlation with disease activity, extent of disease, detection of erythrocyte sedimentation rate and c-reactive protein in active UC. Moreover, plasma IL-17 was higher in patients with active UC, and a similar trend applied to the mRNA levels of RORγt and T-bet in peripheral blood mononuclear cells (PBMCs). The levels of p-STAT3 and p-STAT5 in PBMCs, as well as the ratio of p-STAT3/p-STAT5, were also elevated in active UC patients. Taken together, our findings revealed that elevated circulating Th17, Th1 and Tc1 cells and the aberrant activation of the STAT pathway may be implicated in the progression of UC. These findings may provide preliminary experimental clues for the development of new therapies for UC.

RhoBTB2 (DBC2) functions as tumor suppressor via inhibiting proliferation, preventing colony formation and inducing apoptosis in breast cancer cells

RhoBTB2 was isolated recently as a tumor suppressor gene from sporadic breast cancer. Although RhoBTB2 was found to be frequently lost in breast cancer and a variety of cancers, its antitumor effect, however, remains unclear. In this study, we constructed a recombinant expression vector pEGFP-N1-RhoBTB2 and transfected it into RhoBTB2-negative breast tumor cell line T-47D. Stable transformanted cells were identified by fluorescence microscope, RT-PCR and Western blot. Cell viability was measured by MTT assay. Colony forming efficiency of breast tumor cells was detected by colony formation assay. Morphological change of apoptotic cells was observed by hematoxylin-eosin staining. Apoptotic ratio was determined by flow cytometry. Cell invasion and migration ability assay were performed using transwell system. Overexpression of RhoBTB2 in breast tumor cells significantly inhibited the proliferation and colony formation of tumor cells. In addition, RhoBTB2 also elevated the apoptotic ratio and caused typical changes of apoptotic morphology in breast tumor cells of RhoBTB2 overexpression. But RhoBTB2 did not influence the invasion and migration ability of breast tumor cells. Therefore, RhoBTB2 is an important tumor suppressor gene related with breast cancer and may play antitumor roles by inhibiting proliferation, preventing colony formation and promoting the apoptosis of tumor cells. However, the precise mechanism behind the antitumor effects of RhoBTB2 needs to be investigated further.

Aberrant expression of chemokine receptor CCR4 in human gastric cancer contributes to tumor‐induced immunosuppression

The chemokine receptor CCR4 is preferentially expressed on certain immune cells and some hematological tumor cells, which play pivotal roles in suppression of host immune response. However, the reasons for the upmodulation of CCR4 and its immune functions in solid tumors remain unclear. Herein, we aimed to determine the expression profiles of CCR4 in gastric cancer cells and its role in regulating antitumor immunity. CCR4 expression was assessed in 63 cases of gastric carcinomas by immunohistochemistry. We found cancer cells in lymphocyte‐rich carcinomas more frequently showed moderate to strong positive staining for CCR4 than those in conventional carcinomas (Pu2003=u20030.041), and also found a positive relationship between expression of CCR4 and tumor necrosis factor‐α (Pu2003=u20030.012). Stimulation of gastric cell lines with various cytokines showed that tumor necrosis factor‐α uniquely upmodulated CCR4 expression through activation of nuclear factor‐κB. Additional coculture experiments showed the forced expression of CCR4 in SGC‐7901 cells caused a significant reduction of γ‐interferon and elevation of interleukin‐10 secretion in the supernatants from cocultured SGC‐7901 cells and PBMCs. In addition, granzyme A production in cancer cell‐cocultured CD56+ natural killer cells was significantly downregulated. Inhibition of the overexpressed CCR4 in cancer cells by an inhibitor of CCR4, compound 39, proved to partly restore the antitumor immunity in respect of the inverse changes in those factors. Our studies suggest that the aberrant expression of CCR4 in human gastric cancer could contribute to tumor‐induced immunosuppression. Conceivably, downmodulation of CCR4 expression could be a promising immunotherapy for human gastric cancer. (Cancer Sci 2011; 102: 1264–1271)

The upregulation of signal transducer and activator of transcription 5-dependent microRNA-182 and microRNA-96 promotes ovarian cancer cell proliferation by targeting forkhead box O3 upon leptin stimulation.

Leptin overexpression contributes to the tumorigenesis of ovarian cancer. However, the functional mechanism and effects remain unclear. The aberrant expression of tumor-related microRNAs may play an important role in the development of cancer. In this report, we demonstrate that crosstalk between leptin and microRNA-182 and microRNA-96 affects the transformation and proliferation of ovarian cancer cells. Our results showed that leptin enhanced the colony formation of ovarian cancer cells in soft agar. A water-soluble tetrazolium salts assay revealed that leptin promoted ovarian cancer cell (SKOV3 and A2780 cells) proliferation in a time- and dose-dependent manner. The growth effects of leptin on ovarian cancer cells were mediated via the reduced expression of forkhead box O3 and its downstream targets p27 and Bim. We demonstrated that leptin upregulated miRNAs that target forkhead box O3 via luciferase reporter assay. Further examination indicated that only the inhibition of microRNA-182 and/or microRNA-96 rescued the expression of forkhead box O3 inhibited by leptin, and their mimics promoted the proliferation of ovarian cancer cells. Moreover, the signal transducer and activator of transcription 5 pathway, but not the signal transducer and activator of transcription 3 pathway, was implicated in the leptin-mediated expression of microRNA-182 and microRNA-96. In conclusion, our findings suggest that the upregulation of microRNA-182 and microRNA-96 targeting forkhead box O3 plays a significant role in the pro-proliferation effect of leptin on ovarian cancer cells, which might provide preliminary experimental clues for the development of new therapies against ovarian cancer.