Yen-Chung Chen

Influence of GSTP1 I105V polymorphism on cumulative neuropathy and outcome of FOLFOX-4 treatment in Asian patients with colorectal carcinoma

Glutathione S‐transferase P1 (GSTP1) participates in detoxification of potentially genotoxic compounds that may alter the efficacy and toxicity of platinum‐based chemotherapy. We analyzed the influence of I105V polymorphism of GSTP1 on clinico‐pathological features and outcomes in 166 Chinese patients with metastatic colorectal carcinoma who had been treated with first‐line FOLFOX‐4. Combined analysis of GSTP1 I105V, ERCC1‐118, and XPD‐751 polymorphisms was also conducted. The results showed that, in comparison with Caucasian populations, a remarkably lower prevalence of Val105 allele variants was noted (24.7%). Patients with Val105 allele variants had a higher response to FOLFOX‐4 (56.1%vs 37.6%, P = 0.04), and a longer progression‐free (P < 0.01) as well as overall (P < 0.01) survival. By adjusted analysis, this polymorphism was identified as an independent prognostic factor (P = 0.01). In combined analysis, patients without any risk genotype, including GSTP1‐105 Ile/Ile, ERCC1‐118 C/T or T/T, and XPD‐751 Lys/Gln, had significantly longer progression‐free and overall survivals (P < 0.01). In addition, patients with Val105 allele variants had a higher incidence of grade 3/4 cumulative neuropathy after different cycles of treatment. These data suggest that Asian populations have a lower prevalence of I105V polymorphism in GSTP1. I105V polymorphism in GSTP1, by reducing its enzymatic activity and consequential detoxification to oxaliplatin, could be a key determinant for a better outcome, but more neurotoxicity, to FOLFOX‐4 treatment. (Cancer Sci 2009)

Downregulation of Sirt1 as aging change in advanced heart failure

BackgroundIn congestive heart failure the balance between cell death and cell survival in cardiomyocytes is compromised. Sirtuin 1 (Sirt1) activates cell survival machinery and has been shown to be protective against ischemia/reperfusion injury in murine heart. The role of Sirt1 in heart failure, especially in human hearts is not clear.ResultsThe expression of Sirt1 and other (associated) downstream molecules in human cardiomyocytes from patients with advanced heart failure was examined. Sirt1 was down-regulated (54.92% ± 7.80% in advanced heart failure samples compared with healthy control cardiomyocytes). The modulation of molecules involved in cardiomyocyte survival and death in advanced heart failure were also examined. The expression of Mn-superoxide dismutase and thioredoxin1, as well as an antiapoptotic molecule, Bcl-xL, were all significantly reduced in advanced heart failure cardiomyoctes (0.71 ± 0.02-fold, 0.61 ± 0.05-fold, and 0.53 ± 0.08-fold vs. control, respectively); whereas the expression of proapoptotic molecule Bax was significantly increased (1.62 ± 0.18-fold vs. control). Increased TUNEL-positive number of cardiomyocytes and oxidative stress, confirmed by 8-hydorxydeoxyguanosine staining, were associated with advanced heart failure. The AMPK-Nampt-Sirt1 axis also showed inhibition in advanced heart failure in addition to severely impaired AMPK activation. Increased p53 (acetyl form) and decreased FoxO1 translocation in the nucleus may be the mechanism of down-regulation of antioxidants and up-regulation of proapoptotic molecules due to low expression of Sirt1.ConclusionIn advanced heart failure, low Sirt1 expression, like aging change may be a significant contributing factor in the downregulation of antioxidants and upregulation of proapoptotic molecules through the p53, FoxO1, and oxidative stress pathways.

Human cytomegalovirus preferentially infects the neoplastic epithelium of colorectal cancer: a quantitative and histological analysis.

BACKGROUND It has long been suggested that human cytomegalovirus (HCMV) might be involved in human oncogenesis. However, whether HCMV was associated with colorectal cancer (CRC) was still controversial. OBJECTIVE To clarify whether HCMV specifically infects the tumorous tissue of CRC. STUDY DESIGN Paired tumor and adjacent non-neoplastic CRC specimens were collected from 163 patients. HCMV DNA was detected and quantified through PCR and quantitative real-time PCR. Virus location was determined by in situ hybridization (ISH) of formalin-fixed paraffin-embedded tissue sections with an HCMV-specific probe. RESULTS By PCR, HCMV DNA was detected in 42.3% (69/163) of the tumor specimens, while only 5.6%(14/163) samples of adjacent non-neoplastic tissue were positive for HCMV (p<0.0001). Quantitative real-time PCR in 54 sample pairs revealed significantly higher viral copies in the tumor specimens than the adjacent non-neoplastic tissue specimens (p<0.001). By ISH, the nucleic acids of HCMV were detected in the cytoplasm of neoplastic epithelium. No hybridization was detected in the inflammatory infiltrates, submucosa, or other stromal tissues. CONCLUSIONS HCMV preferentially infects the tumor epithelium of CRC. How the virus subsists in and interacts with the microenvironment of tumor epithelium of CRC should be studied.

Bacteriology of acute appendicitis and its implication for the use of prophylactic antibiotics.

BACKGROUND To prevent surgical site infection (SSI) after appendectomy, antibiotic prophylaxis has been recommended for all patients, but this approach is based largely on bacteriologic findings that are decades old. The objective of this study was to reevaluate the bacteriology of acute appendicitis in order to assess the usefulness of current antibiotic prophylaxis. METHODS Between January 1 and December 31, 2010, 117 patients with pathology-proved acute appendicitis were recruited. Antibiotic prophylaxis was given according to national guidelines. Immediately after operation, the luminal contents of the appendices were swabbed for bacterial culture. The charts of the patients were surveyed retrospectively for postoperative complications until June 30, 2011. RESULTS Bacteria were isolated from 115 of 117 specimens sent for culture (98%). Of the 115 samples that yielded bacteria, all gave rise to aerobic isolates and five yielded mixed aerobic and anaerobic isolates. The most common aerobic organism was Escherichia coli, which was present in 100 of 117 patients who had pathology-proved acute appendicitis (85%). Less frequent organisms were Klebsiella pneumoniae (30 cases; 26%), Streptococcus spp. (29 cases; 25%), Enterococcus spp. (21 cases; 18%), and Pseudomonas aeruginosa (18 cases; 15%). All P. aeruginosa isolates were sensitive to amikacin, ceftazidime, and cefepime; but seven of the eight were resistant to cefuroxime. Eight patients were identified as having had a postoperative SSI, and P. aeruginosa was isolated from five of these cases. The isolation of P. aeruginosa correlated significantly with SSI (p=0.002). CONCLUSIONS The most commonly identified aerobic bacteria associated with acute appendicitis were E. coli, followed by K. pneumoniae, Streptococcus, Enterococcus, and P. aeruginosa. Pseudomonas aeruginosa frequently was not covered by the prophylactic antibiotics chosen and might be associated with SSI.

Phosphorylation of telomeric repeat binding factor 1 (TRF1) by Akt causes telomere shortening.

Telomeric repeat binding factor 1 (TRF1) belongs to the shelterin complex, which modulates the telomere structures. Akt/protein kinase B activation caused genomic instability and contributes to tumorigenesis, although the molecular mechanism remained little known. Here, we show the direct interaction between Akt and TRF1. In vitro kinase assays showed the phosphorylation of a putative Akt phosphorylation site (Threonine 273) in wild type TRF1, but not the mutant TRF1 (T273A), by Akt. Overexpression of Akt decreased telomere length in a HTC cell line. These results indicate that Akt plays an important role in telomere length regulation, contributing to genomic instability and tumorigenesis.

Tumoral presence of human cytomegalovirus is associated with shorter disease-free survival in elderly patients with colorectal cancer and higher levels of intratumoral interleukin-17

Infectious diseases are closely related to cancer. Human cytomegalovirus (HCMV) has been implicated in the promotion of tumour growth, and is present in the tumour specimens of colorectal cancer (CRC). This study aimed to investigate whether tumoral presence of HCMV is associated with a different clinical outcome in elderly patients with CRC. We analysed archived tumour specimens from 95 CRC patients aged ≥65 years. HCMV was detected by PCR. Clinical, pathological, disease-free and overall survival data were compared between patients with HCMV-positive and HCMV-negative tumours. A quantitative RT-PCR array was used to evaluate the expression levels of cytokines genes of T-helper subpopulations in tumours. In the Kaplan-Meier analysis of the 81 patients who underwent curative surgery, 39 patients with HCMV-positive tumours had a lower disease-free survival rate (p 0.024). For patients with stage II or stage III tumours, tumoral HCMV status correlated with disease-free survival more closely than the traditional histopathological staging methods. In a multivariate Cox proportional hazard model, tumoral presence of HCMV independently predicted tumour recurrence in 5 years (hazard ratio 4.42; 95% CI 1.54-12.69, p 0.006). The qRT-PCR analysis of ten stage II tumours showed that the gene expression levels of interleukin-17-the signature cytokine of T-helper 17 cells-and its receptor, interleukin-17 receptor C, were higher in the five HCMV-positive tumours. Our results suggest that the presence of HCMV in CRC is associated with poorer outcome in elderly patients. How the virus interacts with the tumour microenvironment should be further investigated.

CBX3/heterochromatin protein 1 gamma is significantly upregulated in patients with non–small cell lung cancer

Lung cancer is typically categorized into small cell lung cancer (SCLC) and non–small cell lung cancer (NSCLC). NSCLC comprises of the majority of lung cancer with a poor prognosis in advanced cases. Transcriptional profiling studies, including microarrays and RNA‐sequencing studies, have significantly enriched our knowledge of gene expression patterns in NSCLC. A recent transcriptional profiling study identified high prevalence of CBX3/HP1‐gamma upregulation in human NSCLC samples. CBX3/HP1‐gamma is an isoform of the heterochromatin protein 1 family, which plays a role in heterochromatin formation and is linked to cancer.

Identification of human cytomegalovirus in tumour tissues of colorectal cancer and its association with the outcome of non-elderly patients.

Increasing evidence suggests that human cytomegalovirus (HCMV) plays an oncomodulatory role in human cancers. In colorectal cancer (CRC), presence of HCMV in tumours has been associated with a poor outcome in elderly patients. This study aimed to investigate the association between HCMV and the outcome of non-elderly patients with CRC. In tumour samples, HCMV DNA was detected by PCR. Viral transcript and protein were detected by in situ hybridization (ISH) and immunohistochemical staining (IHC), respectively. Clinical, pathological and survival data were compared between patients with HCMV-positive and -negative tumours. Quantitative reverse transcription PCR (qRT-PCR) was used to analyse the expression levels of cellular signals related to CRC progression and metastasis. Among 89 CRC non-elderly patients aged <65 years, HCMV was detected in 31 (34.8 %) tumour samples by PCR. By ISH and IHC, viral transcript and protein specifically localized to the cytoplasm of neoplastic mucosal epithelium. Outcome analysis revealed a more favourable disease-free survival (DFS) rate in patients with HCMV-positive tumours (P<0.01), specifically in patients with stage III disease. In a multivariate Cox proportional-hazard model, tumoural presence of HCMV independently predicted a higher DFS rate (hazard ratio 0.22; 95 % confidence interval 0.075-0.66, P<0.01). By qRT-PCR, the tumoural levels of interleukin-1 were relatively lower in samples positive for HCMV. The results suggest that HCMV may influence the outcome of CRC in an age-dependent manner and possibly has a dual oncomodulatory effect. How the virus interacts with the tumour microenvironment should be further studied.

Interaction between NBS1 and the mTOR/Rictor/SIN1 Complex through Specific Domains

Nijmegen breakage syndrome (NBS) is a chromosomal-instability syndrome. The NBS gene product, NBS1 (p95 or nibrin), is a part of the Mre11-Rad50-NBS1 complex. SIN1 is a component of the mTOR/Rictor/SIN1 complex mediating the activation of Akt. Here we show that NBS1 interacted with mTOR, Rictor, and SIN1. The specific domains of mTOR, Rictor, or SIN1 interacted with the internal domain (a.a. 221-402) of NBS1. Sucrose density gradient showed that NBS1 was located in the same fractions as the mTOR/Rictor/SIN1 complex. Knockdown of NBS1 decreased the levels of phosphorylated Akt and its downstream targets. Ionizing radiation (IR) increased the NBS1 levels and activated Akt activity. These results demonstrate that NBS1 interacts with the mTOR/Rictor/SIN1 complex through the a.a. 221–402 domain and contributes to the activation of Akt activity.