hMSH2 Gene Expression Research Articles

Association of expression of inflammatory response genes and DNA repair genes in colorectal carcinoma.

Inflammation is an important etiological factor of colorectal carcinoma and may be related to colorectal carcinoma growth and proliferation. This study aimed to verify whether the presence of chronic inflammation represented by tumor necrosis factor-α, interleukin-2, interleukin-6, and interleukin-10 gene expression is related to hMLH1, hMSH2, hMSH6, and PMS2 gene expression and the corresponding protein levels of these genes from the DNA repair system. A total of 83 patients were operated on for curative or palliative colorectal carcinoma. Expression of the inflammatory response genes tumor necrosis factor-α, interleukin-2, interleukin-6, and interleukin-10 as well as expression of the hMLH1, hMSH2, hMSH6, and PMS2 genes of the DNA repair system (mismatch repair) and the expression levels of the corresponding mismatch repair proteins were measured in neoplastic tissue by reverse transcription polymerase chain reaction and immunohistochemistry, respectively. Associations were observed between hMSH6 mRNA expression and interleukin-2 mRNA expression (p = 0.026) as well as between hMLH1 and hMSH2 gene expression and tumor necrosis factor-α gene expression (p = 0.042). Higher tissue levels of interleukin-2 and tumor necrosis factor-α gene expression were associated with lower hMSH6, hMLH1, and hMSH2 gene expression.

MiR-21 induces cell cycle at S phase and modulates cell proliferation by down-regulating hMSH2 in lung cancer

MicroRNAs regulate critical genes associated with lung cancer. Human mutS homolog 2 (hMSH2), one of the core mismatch repair genes, is affected in lung cancer development. The aim of this study is to investigate the role of miR-21 in hMSH2 gene expression and the effect of miR-21 on cell proliferation and cell cycle in lung cancer. The targets of miR-21 were predicted by a bioinformatics tool, and hMSH2 was validated as a direct target of miR-21 by luciferase activity assay. MiRNA mimics or inhibitors were used to stimulate or attenuate the effect of endogenous miR-21 on hMSH2 expression. MiR-21 and hMSH2 expressions were assessed with real-time RT-PCR and Western blotting. Cell cycle was determined by flow cytometry, and cell growth was analyzed by MTT assay and real-time cell analysis system. MiR-21 expression was inversely correlated with hMSH2 expression in human lung cancer cell lines. Further validation showed hMSH2 was directly regulated by miR-21. The up-regulation of miR-21 significantly promoted cell proliferation and revealed a higher proportion of cells at S phase. However, knockdown of miR-21 expression resulted in cell cycle arrest at G2/M phase and inhibited cell proliferation. These data suggest miR-21 is a key regulator of hMSH2 and modulates cell cycle and proliferation by targeting hMSH2 in human lung cancer.

The correlation between serum estrogen level and the expression of mismatch repair genes in colonic mucosa

Objective To investigate the effects of estrogen on mismatch repiar gene expression in colonic mucosa in vivo. Methods A total of 42 healthy individuals underwent colonoscopy were enrolled in the study. Half an hour before colonoscopy examination, blood sample was taken for determining the serum estradiol (E2) level. N ormal colonic mucosal tissues determined by naked eye under colonoscopy examination were taken in the right hemi colon to detect HMLH1 and hMSH2 gene expression by semi-quantitative RT-PCR and immunohistochemistry staining. Then the correlation of serum E2 levels with hMLH1 and hMSH2 expression in colonic mucosa was analyzed. Results A bimodal curve was presented for the correlation between serum E2 level in healthy individuals and hMLH1 expression in colonic mucosa. A strong positive correlation of E2 level with hMLH1 expression in normal colonic mucosa was observed when serum E2 level was more than 45 pg/ml (For mRNA, P=0. 003, r=0. 701; for immunohistochemistry positivity index, P=0. 000, r=0. 874).However there was no correlation between E2 level and hMSH2 expression. Conclusion High serum E2 level might increase the hMLH1 gene expression in colonic mucosa in vivo. Key words: Estrogen; Mismatch repair; Colorectal cancer

Loss of hMSH2 gene expression correlates with improved survival in patients with sporadic colorectal cancer

gene expression hadthe tendency to longer survival in all Dukes’ stages.Loss of mismatch repair (MMR) function is implicatedin the phenomena of microsatellite instability (MSI), whichis characterized by the accumulation of somatic alterationin the length of simple, repeated sequences; microsatellites(Ahmed 2003). MSI has been identified in tumours of hered-itary non-polyposis colorectal cancer (HNPCC) colorectalcancer and sporadic colorectal cancer, where it occurs in 10–15% of the cases (Gryfe

Age Related Expression of hMLH1 but Not hMSH2 in Human Hematopoietic Stem Cells Predicts Genomic Instability.

Abstract 3235Poster Board III-172DNA damage repair pathways have been shown to be important for hematopoietic function and longevity. A number of studies focusing on the loss of DNA damage repair genes have reported age related loss of hematopoietic stem cells, reduced hematopoietic function, and increased rates of hematologic cancer. A poorly studied pathway with respect to its effect on hematopoietic function is the mismatch repair (MMR) pathway. Microsatellite instability (MSI), one marker of MMR failure, has been observed in acute lymphoblastic leukemia, myelodysplastic syndrome, and lymphocytes obtained from the peripheral blood of the elderly. Further, studies investigating MMR pathway disruption in mice show an increased incidence of age related hematologic disorders and failure to repopulate in competitive transplant experiments. These reports led to the formation of the hypothesis that age related loss of MMR in a subset hematopoietic stem/progenitor cells (HSC) leads to a progenitor population with a mutator phenotype potentially leading to cell death or leukemogenesis.To test this hypothesis we clonally expanded HSC from cord blood, bone marrow, and bone core samples from various aged individuals most of whom had normal CBCs. These colony forming units (CFU) were then tested for MSI at five microsatellite loci previously used in the diagnosis of the MMR defective disease HNPCC (BAT 25, BAT 26, D2S123, D5S346, and D17S250). These results showed a statistically significant increase in high grade instability (measured as MSI observed at >20% of loci tested) in CFU obtained from individuals over the age of 50 compared to those in the age range between 0 and 50 years (p=0.0034). Next we sought to determine if loss of gene expression in MMR genes could account for the observed MSI. Gene expression of two genes known to be transcriptionally downregulated in MMR failure, hMLH1 and hMSH2, were assessed by qRT-PCR in CFU obtained from pure CD34+ immunomagnetic separations of HSC from various aged donors. Further, individual CD34+ cells from these same donors were fixed to slides and immunostained for hMLH1 and hMSH2. We observed a significant loss of hMLH1 gene expression in a subset of HSC obtained from older donors above age 42, but no pattern of loss of hMSH2 gene expression. The age related loss of MMR in HSC suggests that MMR pathway proficiency is important for hematopoiesis. These results suggest that loss of MMR might precede myelodysplastic syndromes and leukemia in older individuals. DisclosuresNo relevant conflicts of interest to declare.

TISSUE MICROARRAY ANALYSIS OF hMSH2 EXPRESSION PREDICTS OUTCOME IN MEN WITH PROSTATE CANCER

Mismatch repair genes are responsible for the coordinated correction of misincorporated nucleotides formed during DNA replication. Mismatch repair expression is altered in a subset of prostate cancers (PCs) and a recent study suggested that time to biochemical recurrence following prostatectomy correlated with the degree of hMSH2 immunohistochemical staining. We compared hMSH2 expression and survival in clinically organ confined PC. A prostate tissue microarray was constructed using 243 specimens from patients who underwent radical prostatectomy with extended lymph node dissection for clinically organ confined PC with up to 12 years of followup. Immunohistochemistry was performed with anti-human MSH2 monoclonal antibody. Three independent observers evaluated hMSH2 expression on a scale of 0 to 4. Low expression was defined as a score of less than 2 and high expression was defined as a score of 2 or higher. Statistical analysis used the Fisher exact test, and Goodman and Kruskal gamma coefficient. Higher Gleason score significantly correlated with higher hMSH2 expression (p < 0.0002). Low hMSH2 expression correlated with increased overall, disease-free and biochemical disease-free survival (all p < 0.01). Analysis comparing low vs high hMSH2 expression was significant with respect to overall (p = 0.0004), disease-free (p = 0.005) and biochemical disease-free (p = 0.0177) survival. hMSH2 is differentially expressed in malignant prostate tissue and hMSH2 immunohistochemical staining intensity correlates with Gleason score, overall and disease-free survival. Taken together our results suggest that hMSH2 expression may be a useful prognostic biomarker for outcome in men with clinically organ confined PC.

Microsatellite instability and hMLH1 and hMSH2 gene expression in Taiwanese hereditary nonpolyposis colorectal cancer.

The mutation rate of hMSH2 and hMLH1 (20%) in Taiwanese hereditary nonpolyposis colorectal cancer (HNPCC) is lower than that reported in other countries. This study aimed to examine the microsatellite instability (MSI) status and gene expression pattern of Taiwanese HNPCC in an effort to establish correlation between these data and results of prior genetic screening. The "Bethesda markers" were used for the MSI analysis. Tumor and neighboring tissues were obtained from 10-mm sections of neutral formalin-fixed, paraffin-embedded, hematoxylin and eosin-stained specimens with a PixCell laser-capture microdissector. Four-mm sections were used for the immunohistochemical analysis by avidin-biotin complex method and final coloring with diaminobenzidine. A pathologist performed scoring of the pathological specimens twice, using a double-blinded methodology. Thirteen tissue blocks from 8 HNPCC families (Amsterdam's criteria) were included in this study. Although the majority of the HNPCC tissues displayed a MSI-high phenotype (10/13, 76.9%), lack of expression of MSH2 and MLH1 was infrequent. Furthermore, only 1 germ-line mutation was detected in the peripheral blood leukocytes of the patients whose tumors had lost protein expression of MSH2 or MLH1. Our results indicate that the pathogenesis of Taiwanese HNPCC is different from that in other countries. Rather than immunohistochemical analysis, MSI status, and genetic screening, clinical history remains a reliable method for diagnosis of HNPCC in Taiwanese the population.

Microsatellite Instability Is Associated with Hypermethylation of the hMLH1 Gene and Reduced Gene Expression in Mycosis Fungoides

Fifty-one mycosis fungoides samples were analyzed for microsatellite instability (MSI) using the panel of markers recommended for hereditary nonpolyposis colorectal cancer kindred and a panel we designed for cutaneous T cell lymphoma in order to compare detection rates and determine if MSI is a genome-wide phenomenon. Samples demonstrating MSI were analyzed for abnormalities of the hMLH1 gene including loss of heterozygosity, mutations, and promoter hypermethylation. MSI was detected in 16% using the hereditary nonpolyposis colorectal cancer panel and 22% with the cutaneous T cell lymphoma panel. Overall, 27% demonstrated MSI and 73% had a stable phenotype. hMLH1 gene studies did not detect loss of heterozygosity or reveal any mutations. Promoter hypermethylation was detected in nine of 14 patients with MSI, however (64%). In addition hMLH1 and hMSH2 protein expression was studied using immunohistochemical techniques. Five of nine patients with MSI and hMLH1 promoter methylation showed abnormal hMLH1 protein expression with normal hMSH2 gene expression. All other patients tested demonstrated normal hMLH1 and hMSH2 protein expression. MSI was found to be more prevalent in tumor stage mycosis fungoides (47%) than early stage disease (20%) and was associated with an older age of onset of mycosis fungoides. MSI may be a consequence of hMLH1 promoter hypermethylation in mycosis fungoides patients and may prevent transcription in a subset of patients. This suggests that the development of a mutator phenotype may contribute to disease progression in mycosis fungoides.

Differential expression of the mismatch repair gene hMSH2 in malignant prostate tissue is associated with cancer recurrence

Mismatch repair (MMR) genes are responsible for coordinated correction of misincorporated nucleotides formed during DNA replication. Inactivating mutations in MMR genes have been described in sporadic cancers and a hereditary cancer predisposition syndrome. Mismatch repair deficiency causes instability at microsatellites and increased mutation rates. Although microsatellite instability (MSI) has been described in high-grade and lymph node positive prostate carcinoma specimens, an analysis comparing hMSH2 expression, MSI, and outcome in clinically organ confined prostate carcinoma has not been reported. Immunohistochemical analysis of benign and malignant prostate tissue from 101 patients was performed using a monoclonal antibody specific for the hMSH2 protein. Expression was correlated with MSI using dinucleotide repeat markers and laser-captured microdissected DNA from normal and tumor cells. hMSH2 protein expression and MSI were assessed with respect to pathologic stage, Gleason score, and time to detectable serum prostate specific antigen (PSA) after prostatectomy in patients with clinically localized prostate carcinoma. In normal glands, hMSH2 staining was minimal to low and confined to the basal cell layer. In 32% of benign prostatic hyperplasia cases, hMSH2 staining was increased in the basal and luminal cell layers whereas 71% of cancer specimens had uniform moderate to high staining. Microsatellite instability was detected in 60% of absent to low staining and 26% of moderate to high staining prostate carcinoma specimens. Differential staining in benign versus malignant prostate tissues was statistically significant (P < 0.001) as was the correlation between absent to low hMSH2 staining and presence of MSI (P = 0.028). Decreased risk for PSA recurrence after radical prostatectomy correlated with absent to low hMSH2 staining in malignant prostate tissue but was only marginally significant (P = 0.05 for 24 month recurrence and P = 0.08 for overall time to PSA recurrence). The results of the current study demonstrate differential hMSH2 expression in benign and malignant prostate tissue. Moreover, hMSH2 expression is altered in a subset of clinically localized prostate carcinoma specimens independent of pathologic stage and Gleason pattern. A statistically significant correlation between hMSH2 immunohistochemical staining intensity and MSI also was identified in prostate carcinoma specimens. Furthermore, the time to cancer recurrence as determined by detectable serum PSA after prostatectomy was associated with hMSH2 staining intensity. Taken together, our results suggest that hMSH2 gene expression in prostate carcinoma may be a useful prognostic marker for outcome in men with clinically organ confined prostate carcinoma.