Xiao Shi Zhang

The expression of beclin 1 is associated with favorable prognosis in stage IIIB colon cancers.

Beclin-1 is a key modulator bridging autophagy, apoptosis and differentiation. This study investigated the expression of beclin-1 in human colon cancers and its association with clinicopathological characteristics. A total of 115 cases of cancer tissues with intact follow-up data were obtained from colon cancer patients with stage IIIB. The expression of beclin-1 in cancer nest and adjacent normal tissue was examined with immunohistochemistry. The results showed the immunostaining of beclin-1 was distributed in plasma-membrane, cytoplasm and nucleus in tumor cells, which occurred in 98 cases (85.2%) of the 115 patients. No or modest beclin-1 expression was observed in adjacent non-cancerous tissues. The higher level of beclin-1 expression strongly associated with longer survival. Both univariate analysis and multivariate analysis showed that the beclin-1 expression and invasive depth of primary mass (T stage) were independent prognostic factors. Additionally, there was no significant correlation of beclin-1 expression with clinicopathological characteristics, such as sex, age, site of primary mass, pathological classification, grade, and invasive depth with the nonparametric correlation Kendall’s tau-b test．Thus, it obviously manifests that beclin-1 is a favorable prognostic biomarker in locally advanced colon carcinomas and provides the information regarding the likely targeted therapy intervention.

The density of macrophages in the invasive front is inversely correlated to liver metastasis in colon cancer

BackgroundAlthough an abundance of evidence has indicated that tumor-associated macrophages (TAMs) are associated with a favorable prognosis in patients with colon cancer, it is still unknown how TAMs exert a protective effect. This study examined whether TAMs are involved in hepatic metastasis of colon cancer.Materials and methodsOne hundred and sixty cases of pathologically-confirmed specimens were obtained from colon carcinoma patients with TNM stage IIIB and IV between January 1997 and July 2004 at the Cancer Center of Sun Yat-Sen University. The density of macrophages in the invasive front (CD68TFHotspot) was scored with an immunohistochemical assay. The relationship between the CD68TFHotspot and the clinicopathologic parameters, the potential of hepatic metastasis, and the 5-year survival rate were analyzed.ResultsTAMs were associated with the incidence of hepatic metastasis and the 5-year survival rate in patients with colon cancers. Both univariate and multivariate analyses revealed that the CD68TFHotspot was independently prognostic of survival. A higher 5-year survival rate among patients with stage IIIB after radical resection occurred in patients with a higher macrophage infiltration in the invasive front (81.0%) than in those with a lower macrophage infiltration (48.6%). Most importantly, the CD68TFHotspot was associated with both the potential of hepatic metastasis and the interval between colon resection and the occurrence of hepatic metastasis.ConclusionThis study showed evidence that TAMs infiltrated in the invasive front are associated with improvement in both hepatic metastasis and overall survival in colon cancer, implying that TAMs have protective potential in colon cancers and might serve as a novel therapeutic target.

Tumor-induced myeloid-derived suppressor cells promote tumor progression through oxidative metabolism in human colorectal cancer

BackgroundExpansions of myeloid-derived suppressor cells (MDSCs) have been identified in human solid tumors, including colorectal cancer (CRC). However, the nature of these tumor-associated MDSCs and their interactions with tumor cells in CRC are still poorly understood.MethodsThe percentages and phenotype of MDSCs in peripheral blood and tumorous and paraneoplastic tissues from CRC patients, as well as the clinical relevance of these MDSCs, were assessed. Age-matched healthy donors were included as controls. The interaction between MDSCs and T cells or tumor cells was investigated in a coculture system in vitro, and the molecular mechanism of the effect of MDSCs on T cells or tumor cells was evaluated.ResultsWe discovered that CRC patients had elevated levels of CD33+CD11b+HLA-DR− MDSCs in primary tumor tissues and in peripheral blood, and the elevated circulating MDSCs were correlated with advanced TNM stages and lymph node metastases. Radical resection significantly decreases the proportions of circulating MDSCs and CD4+CD25highFOXP3+ regulatory T cells. In vitro, CRC cells mediate the promotion of MDSC induction. Moreover, these tumor-induced MDSCs could suppress T cell proliferation and promote CRC cell growth via cell-to-cell contact. Such effects could be abolished by the inhibition of oxidative metabolism, including the production of nitric oxide (NO), and reactive oxygen species (ROS).ConclusionsOur results reveal the functional interdependence between MDSCs, T cells and cancer cells in CRC pathogenesis. Understanding the impact of MDSCs on T cells and tumor cells will be helpful to establish an immunotherapeutic strategy in CRC patients.

Co-expression of nuclear and cytoplasmic HMGB1 is inversely associated with infiltration of CD45RO+ T cells and prognosis in patients with stage IIIB colon cancer

BackgroundThe intratumoral infiltration of T cells, especially memory T cells, is associated with a favorable prognosis in early colorectal cancers. However, the mechanism underlying this process remains elusive. This study examined whether high-mobility group box 1 (HMGB1), a damage-associated molecular pattern (DAMP) molecule, is involved in the infiltration of T cells and disease progression in locally advanced colon cancer.MethodsSeventy-two cases of pathologically-confirmed specimens were obtained from patients with stage IIIB (T3N1M0) colon cancer who underwent radical resection between January 1999 and May 2002 at the Cancer Center of Sun Yat-Sen University. The density of tumor-infiltrating lymphocytes (TILs) within the tumor tissue and the expression of HMGB1 in the cancer cells were examined via immunohistochemical analysis. The phenotype of CD45RO+ cells was confirmed using a flow cytometric assay. The association between HMGB1 expression, the density of TILs, and the 5-year survival rate were analyzed.ResultsThe density of CD45RO+ T cells within the tumor was independently prognostic, although a higher density of CD3+ T cells was also associated with a favorable prognosis. More importantly, the expression of HMGB1 was observed in both the nucleus and the cytoplasm (co-expression pattern) in a subset of colon cancer tissues, whereas nuclear-only expression of HMGB1 (nuclear expression pattern) existed in most of the cancer tissues and normal mucosa. The co-expression pattern of HMGB1 in colon cancer cells was inversely associated with the infiltration of both CD3+ and CD45RO+ T cells and 5-year survival rates.ConclusionsThis study revealed that the co-expression of HMGB1 is inversely associated with the infiltration of CD45RO+ T cells and prognosis in patients with stage IIIB colon cancer, indicating that the distribution patterns of HMGB1 might contribute to the progression of colon cancer via modulation of the local immune response.

Chloroquine enhances the cytotoxicity of topotecan by inhibiting autophagy in lung cancer cells.

Although the anti-malaria drug chloroquine (CQ) has been shown to enhance chemotherapy and radiation sensitivity in clinical trials, the potential mechanisms underlying this enhancement are still unclear. Here, we examined the relevant mechanisms by which the multipotent CQ enhanced the cytotoxicity of topotecan (TPT). The lung cancer cell line A549 was treated with TPT alone or TPT combined with CQ at non-cytotoxic concentrations. Cell viability was assessed using the MTT assay. The percentage of apoptotic cells and the presence of a side population of cells were both determined by flow Cytometry. Autophagy and the expression of Bcl-2 family proteins were examined by Western blotting. The accumulation of YFP-LC3 dots and the formation of acidic vesicular organelles were examined by confocal microscopy. CQ sensitized A549 cells to TPT and enhanced TPT-induced apoptosis in a Bcl-2 family protein-independent fashion. CQ inhibited TPT-induced autophagy, which modified the cytotoxicity of TPT. However, CQ failed to modify the transfer of TPT across the cytoplasmic membrane and did not increase lysosomal permeability. This study showed that CQ at non-cytotoxic concentrations potentiated the cytotoxicity of TPT by interfering with autophagy, implying that CQ has significant potential as a chemotherapeutic enhancer.

Identification of anaplastic lymphoma kinase break points and oncogenic mutation profiles in acral/mucosal melanomas.

Acral and mucosal melanomas, the two most common subtypes of melanoma in China, exhibit different genetic alterations and biologic behavior compared with other subtypes of melanomas. The purpose of this study was to identify the genetic alterations in patients with acral or mucosal melanomas in southern China. Fluorescence in situ hybridization (FISH), immunohistochemistry (IHC) analysis, polymerase chain reaction (PCR), and quantitative real‐time reverse transcriptase PCR (qRT‐PCR) were used to assess the anaplastic lymphoma kinase (ALK) break points. Furthermore, a mass spectrometry–based genotyping platform was used to analyze 30 acral melanomas and 28 mucosal melanomas to profile 238 known somatic mutations in 19 oncogenes. ALK break points were identified in four acral cases (6.9%). Eight (13.8%) cases harbored BRAF mutations, six (10.3%) had NRAS mutations, four (6.9%) had KIT mutations, two (3.5%) had EGFR mutations, two (3.5%) had KRAS mutations, two (3.5%) had MET mutations, one (1.7%) had an HRAS mutation, and one (1.7%) had a PIK3CA mutation. Two cases exhibited co‐occurring mutations, and one case with a BRAF mutation had a translocation in ALK. This study represents a comprehensive and concurrent analysis of the major recurrent oncogenic mutations involved in melanoma cases from southern China. These data have implications for both clinical trial designs and therapeutic strategies.

The Inhibition of Autophagy Sensitises Colon Cancer Cells with Wild-Type p53 but Not Mutant p53 to Topotecan Treatment

Background Topotecan produces DNA damage that induces autophagy in cancer cells. In this study, sensitising topotecan to colon cancer cells with different P53 status via modulation of autophagy was examined. Methodology/Principal Findings The DNA damage induced by topotecan treatment resulted in cytoprotective autophagy in colon cancer cells with wild-type p53. However, in cells with mutant p53 or p53 knockout, treatment with topotecan induced autophagy-associated cell death. In wild-type p53 colon cancer cells, topotecan treatment activated p53, upregulated the expression of sestrin 2, induced the phosphorylation of the AMPKα subunit at Thr172, and inhibited the mTORC1 pathway. Furthermore, the inhibition of autophagy enhanced the anti-tumour effect of topotecan treatment in wild-type p53 colon cancer cells but alleviated the anti-tumour effect of topotecan treatment in p53 knockout cells in vivo. Conclusions/Significance These results imply that the wild-type p53-dependent induction of cytoprotective autophagy is one of the cellular responses that determines the cellular sensitivity to the DNA-damaging drug topotecan. Therefore, our study provides a potential therapeutic strategy that utilises a combination of DNA-damaging agents and autophagy inhibitors for the treatment of colon cancer with wild-type p53.

Serum diagnosis of diffuse large B-cell lymphomas and further identification of response to therapy using SELDI-TOF-MS and tree analysis patterning

BackgroundCurrently, there are no satisfactory biomarkers available to screen for diffuse large B cell lymphoma (DLBCL) or to identify patients who do not benefit from standard anti-cancer therapies. In this study, we used serum proteomic mass spectra to identify potential serum biomarkers and biomarker patterns for detecting DLBCL and patient responses to therapy.MethodsThe proteomic spectra of crude sera from 132 patients with DLBCL and 75 controls were performed by SELDI-TOF-MS and analyzed by Biomarker Patterns Software.ResultsNine peaks were considered as potential DLBCL discriminatory biomarkers. Four peaks were considered as biomarkers for predicting the patient response to standard therapy. The proteomic patterns achieved a sensitivity of 94% and a specificity of 94% for detecting DLBCL samples in the test set of 85 samples, and achieved a sensitivity of 94% and a specificity of 92% for detecting poor prognosis patients in the test set of 66 samples.ConclusionThese proteomic patterns and potential biomarkers are hoped to be useful in clinical applications for detecting DLBCL patients and predicting the response to therapy.

Proteasome inhibitor MG-132 modifies coxsackie and adenovirus receptor expression in colon cancer cell line lovo

The efficacy of adenovirus vector-based cancer gene therapy is controversial. Its uptake by cells in many cases requires the major receptor for adenoviruses, the coxsackievirus and adenovirus receptor (CAR). Low transduction is believed to be one of the main barriers as the expression of CAR on tumor cells is frequently reduced. Increasing CAR expression on tumor cells thus offers a promising opportunity for more effective adenovirus based treatment. Expression of CAR in 62 cases of colon tumor specimens were examined with immunohistochemistry. To modify the CAR expression, the effects of proteasome inhibitor MG132 on CAR expression of colon cancer cell lines were determined by flow cytometry, RT-PCR, and western blot. To evaluate adenovirus transfer, we further used rAd.EGFP, rAd.p53, and oncolytic adenovirus to infect target cells. The CAR expression was significantly decreased in colon carcinomas, both in primary tumors and lymphonode metastasis. Though the deregulation of CAR occurred in early disease and showed no relationship with TNM stage, when primary tumors are more than 5 cm in diameter, this deregulation becomes more frequent. More importantly, proteasome inhibitor MG-132 could enhance CAR expression in colon carcinoma cell line lovo, accompanied with enhanced adenovirus transfer, target gene expression, and oncolysis. These data provide a rational basis for evaluation of CAR expression in tumors and pretreatment with CAR conditioner prior to adenovirus vector-based gene therapy.

Reactive oxygen species mediate oxaliplatin-induced epithelial-mesenchymal transition and invasive potential in colon cancer

Therapeutic benefits offered by common chemotherapy drugs, such as oxaliplatin, are limited due to the development of resistance, which contributes to treatment failure and metastasis. The epithelial-mesenchymal transition (EMT) is a key event contributing to the development of resistance to chemotherapeutics. Although the relationship between oxaliplatin and chemotherapy resistance has been described for decades, the molecular mechanisms have remained elusive. The aim of the present study was to investigate the underlying mechanisms of oxaliplatin-mediated metastasis. Here, we identify reactive oxygen species (ROS) as mediators that promote the oxaliplatin-induced EMT. Following oxaliplatin treatment, the messenger RNA (mRNA) levels of most peroxiredoxin family genes, except for peroxiredoxin 1 (prdx1) gene, were constant or even decreased, resulting in ROS abundance. And the antioxidant guardian Nrf2 was unconspicuously raised both transcriptionally and translationally with oxaliplatin treatment as compared to those induced by topotecan treatment, which has been proved with no induced metastasis. In addition, the study evaluated high levels of ROS leading to EMT via activation of the known oncogenes Akt and Snail. Using the Akt inhibitor LY294002 or knocking down Snail expression via RNA interference (RNAi) reversed the effects of oxaliplatin on the EMT and metastasis. Our studies establish a role for the ROS-Akt-Snail axis as a mechanism by which chemotherapeutics induce EMT and cancer metastasis.