Dong Geun Lee

Overexpression of VEGF and Angiopoietin 2: A Key to High Vascularity of Hepatocellular Carcinoma?

Hepatocellular carcinoma (HCC) is becoming one of the most common malignant tumors worldwide and is characterized by a high vascularity. Angiogenesis, formation of new microvessels, is critical for the growth and progression of various human solid tumors. Vascular endothelial growth factor (VEGF) and angiopoietins (Ang1 and Ang2) are endothelial cell–specific vasculogenic and angiogenic growth factors, but their expression and roles in HCC have not been extensively explored. The aim of this study was to determine the expression and cellular localization of VEGF, Ang1, and Ang2 in specimens of resected human HCC using in situ hybridization and immunohistochemical staining and to examine their relationship to microvessel density (MVD) and tumor size. We also investigated whether mutation of p53 protein might affect the expression of the above angiogenic growth factors. VEGF and Ang2 were strongly expressed and localized predominantly to cancer cells, whereas Ang1 was detected in supportive cells of large blood vessels, stromal cells, endothelial cells, and tumor cells. Expression of the VEGF protein and the Ang2 (but not Ang1) mRNA were strongly correlated with MVD (P < .05, P = .001) and tumor size (P < .05). There was also a strong correlation between VEGF protein and Ang2 mRNA expression (P < .001). However, no significant correlation was found between overexpression of p53 and the expression of VEGF, angiopoietins, or MVD. These findings suggest that overproduction of the angiogenic growth factors VEGF and Ang2 by HCC cells may increase vascularity and tumor growth in a paracrine manner. Our findings also suggest that interaction between VEGF and Ang2 may play a critical role in tumor angiogenesis in HCC.

Expression of DBC1 and SIRT1 Is Associated with Poor Prognosis of Gastric Carcinoma

Purpose: SIRT1 (silent mating-type information regulation 2 homologue 1) expression has been reported to predict poor survival in some cancers. We therefore investigated the expression levels of SIRT1 and its negative regulator, DBC1 (deleted in breast cancer 1), in gastric cancer patients. Experimental Design: We evaluated immunohistochemical expression of DBC1, SIRT1, and p53 using 3-mm tumor cores from 177 gastric cancer patients for tissue microarray. Results: Positive expressions of DBC1 and SIRT1 were seen in 62% (109 of 177) and in 73% (130 of 177) of patients, respectively. Expression of DBC1 was significantly correlated with tumor stage (P = 0.007), lymph node metastasis (P < 0.001), tumor invasion (P = 0.001), venous invasion (P = 0.001), histologic types (P < 0.001), p53 expression (P < 0.001), and SIRT1 expression (P < 0.001). SIRT1 expression was also significantly correlated with tumor stage (P < 0.001), lymph node metastasis (P < 0.001), tumor invasion (P < 0.001), histologic types (P < 0.001), and p53 expression (P = 0.001). In addition, expression of DBC1 was significantly associated with shorter overall survival and relapse-free survival by univariate analysis (P < 0.001 and P < 0.001, respectively). SIRT1 expression was also significantly associated with shorter overall survival and relapse-free survival by univariate analysis (P = 0.001 and P = 0.001, respectively). Multivariate analysis showed that tumor stage and expression of DBC1 were independent prognostic factors significantly associated with overall survival and relapse-free survival. Conclusion: This study shows that expression of DBC1 and SIRT1 is a significant prognostic indicator for gastric carcinoma patients.

SIRT1 Expression is Associated With Poor Prognosis of Diffuse Large B-Cell Lymphoma

Sirtuin1 (SIRT1) is a nicotinamide adenine dinucleotide-dependent deacetylase. Recently, it is suggested that SIRT1 may be involved in the development of malignant tumors including mouse lymphoma. Therefore, we investigated the prevalence and the prognostic impact of SIRT1 expression in diffuse large B-cell lymphoma (DLBCL). Immunohistochemical expression of SIRT1, p53, bcl2, CD10, bcl6, and multiple myeloma-1 (MUM1) were evaluated by using a 2 mm core from 104 DLBCL patients for tissue microarray. Positive expression of SIRT1 was seen in 74% (77/104) of patients. In total DLBCL patients, SIRT1 and p53 expression were significantly associated with shorter overall survival (OS) by univariate analysis (P=0.001 and P=0.011, respectively). SIRT1 was also an independent prognostic factor by multivariate analysis (P=0.01). According to the expression patterns of CD10, bcl6, and MUM1, germinal center B cell (GCB) types were represented in 38 cases (37%) and non-GCB types were represented in 66 cases (63%). In the GCB type, only p53 expression was associated with a significantly shorter OS (P=0.032). In the non-GCB type, expression of SIRT1 correlated with shorter OS by univariate analyses (P=0.005) and multivariate analyses (P=0.049). In conclusion, we showed that SIRT1 expression is a clinically significant prognostic indicator for DLBCL patients.

Expression and prognostic significance of SIRT1 in ovarian epithelial tumours.

Aims: Sirtuin1 (SIRT1) is a nicotinamide adenine dinucleotide‐dependent deacetylase. Recently, some studies have suggested that SIRT1 could be over‐expressed in breast, prostate and colon cancers and up‐regulated SIRT1 inactivates p53 by deacetylation. Therefore, we investigated the prevalence and the prognostic impact of SIRT1 and p53 expression in ovarian epithelial tumours. Methods: Immunohistochemical expression of SIRT1 and p53 were evaluated using tissue microarray in 40 cases of benign epithelial tumours, 36 cases of borderline tumours, and 90 cases of malignant tumours. Results: Expression of SIRT1 was significantly increased in malignant epithelial tumours compared to benign and borderline epithelial tumours (p < 0.001). In particular, a high proportion of serous carcinoma expressed SIRT1 (86%, 55/64 cases). Despite the frequent expression of SIRT1 in malignant ovarian epithelial tumours, serous carcinomas of high FIGO stage showed less frequent SIRT1 expression compared to that of low stage serous carcinomas (p = 0.029). Moreover, increased expression of SIRT1 in serous carcinoma correlated with increased overall survival by univariate (p = 0.014) and multivariate analyses. Conclusions: Over‐expression of SIRT1 may play an important role in the early stage of ovarian carcinogenesis.

Involvement of Endoplasmic Reticulum Stress in Myofibroblastic Differentiation of Lung Fibroblasts

Stress that impairs endoplasmic reticulum (ER) function leads to an accumulation of unfolded or misfolded proteins in the ER (ER stress) and triggers the unfolded protein response (UPR). Recent studies suggest that ER stress is involved in idiopathic pulmonary fibrosis (IPF). The present study was undertaken to determine the role of ER stress on myofibroblastic differentiation of fibroblasts. Fibroblasts in fibroblastic foci of IPF showed immunoreactivity for GRP78. To determine the role of ER stress on α-smooth muscle actin (α-SMA) and collagen type I expression in fibroblasts, mouse and human lung fibroblasts were treated with TGF-β1, and expression of ER stress-related proteins, α-SMA, and collagen type I was analyzed by Western blotting. TGF-β1 significantly increased expression of GRP78, XBP-1, and ATF6α, which was accompanied by increases in α-SMA and collagen type I expression in mouse and human fibroblasts. A chemical chaperone, 4-PBA, suppressed TGF-β1-induced UPR and α-SMA and collagen type I induction. We also showed that TGF-β1-induced UPR was mediated through the reactive oxygen species generation. Our study provides the first evidence implicating the UPR in myofibroblastic differentiation during fibrosis. These findings of the role of ER stress and chemical chaperones in pulmonary fibrosis may improve our understanding of the pathogenesis of IPF.

Inactivation of the PTEN gene protein product is associated with the invasiveness and metastasis, but not angiogenesis, of breast cancer.

PTEN is a novel tumor‐suppressor gene located on chromosomal band 10q23. Loss of PTEN function has been implicated  in  the  progression  of  several  types  of  cancer, but the correlation between loss of PTEN expression and advanced carcinomas is not well established. The capacity for angiogenesis of a tumor is known to play a very important role in growth and metastasis, and there have been reports that PTEN relates to angiogenesis. In the present study, formalin‐fixed and paraffin embedded tissues from 101 patients with breast carcinomas, including 88 cases of invasive ductal carcinomas and 13 cases of ductal carcinoma in situ (DCIS), were evaluated by immunohistochemical methods for the expression of PTEN and vascular endothelial growth factor (VEGF), as well as microvessel density (MVD). The results were compared with the clinicopathologic parameters. There was no loss of PTEN expression in any of the cases of DCIS, but 28 (32%) of the 88 invasive cases did not express PTEN. Loss of PTEN expression was associated with lymph node metastasis (P = 0.03), but  did  not  correlate  with  tumor  size,  tumor  grade,  MVD or recurrence. VEGF expression significantly correlated with lymph node metastasis in invasive ductal carcinoma (P = 0.01). There was no correlation between the expression of PTEN and that of VEGF (P = 0.63). The present study suggests that loss of PTEN expression is common and correlates with tumor progression and lymph node metastasis  in  breast  carcinoma.  The  relationship  between  loss of PTEN and progression of breast cancer may not be explained by modulation of angiogenesis.

Expression of ER stress and autophagy-related molecules in human non-small cell lung cancer and premalignant lesions.

Stress that impairs endoplasmic reticulum (ER) function leads to an accumulation of unfolded or misfolded proteins in the ER (ER stress). Autophagy is a lysosomal pathway involved in the turnover of cellular macromolecules and organelles, which emerging data indicate that ER stress is also a potent inducer of autophagy. ER stress and autophagy are involved in human cancer. We examined the expression of ER stress‐related proteins [GRP78 and C/EBP homologous protein (CHOP)] and autophagic proteins (Beclin‐1 and LC3) in non‐small cell lung carcinomas (NSCLCs), bronchioloalveolar carcinomas (BACs) and atypical adenomatous hyperplasias (AAHs) to understand their role in the NSCLC pathogenesis. The expression of GRP78 and CHOP, Beclin‐1 and LC3 were analyzed using immunohistochemistry on tissue sections from 133 NSCLC (69 squamous cell carcinomas, 56 adenocarcinomas (AC) and eight other NSCLCs), 21 BAC and 9 AAH. Expression of GRP78 and Beclin‐1 was correlated with low tumor stage (p < 0.001 and p = 0.019, respectively) and longer survival (p = 0.007 and p <0.001, respectively) by Kaplan–Meier analysis. However, CHOP was correlated with high tumor stage (p = 0.038) and shorter survival (p = 0.012). Expression of GRP78 and Beclin‐1 was positively correlated (p = 0.006). Our study showed that the expression of GRP78, CHOP, Beclin‐1 and LC3 in lung cancer and its relation with clinicopathologic factors and patients survival. These results suggest that GRP78, CHOP and Beclin‐1 may play an important role in tumorigenesis of lung AC and may serve as new prognostic indicators for outcome of the patients with NSCLC.

Effects of Delay in the Snap Freezing of Colorectal Cancer Tissues on the Quality of DNA and RNA

PURPOSE The success of basic molecular research using biospecimens strongly depends on the quality of the specimen. In this study, we evaluated the effects of delayed freezing time on the stability of DNA and RNA in fresh frozen tissue from patients with colorectal cancer. METHODS Tissues were frozen at 10, 30, 60, and 90 minutes after extirpation of colorectal cancer in 20 cases. Absorbance ratio of 260 to 280 nm (A(260)/A(280)) and agarose gel electrophoresis were evaluated. In addition, the RNA integrity number (RIN) was assayed for the analysis of the RNA integrity. RESULTS Regardless of delayed freezing time, all DNA and RNA samples revealed A(260)/A(280) ratios of more than 1.9, and all DNA samples showed a discrete, high-molecular-weight band on agarose gel electrophoresis. The RINs were 7.53 ± 2.04, 6.70 ± 1.88, 6.47 ± 2.58, and 4.22 ± 2.34 at 10, 30, 60, and 90 minutes, respectively. Though the concentration of RNA was not affected by delayed freezing, the RNA integrity was decreased with increasing delayed freezing time. CONCLUSION According to the RIN results, we recommend that the collection of colorectal cancer tissue should be done within 10 minutes for studies requiring RNA of high quality and within 30 minutes for usual RNA studies.

Expression of SIRT1 and cortactin is associated with progression of non-small cell lung cancer.

Cortactin is an F-actin binding protein involved in cell migration and tumor metastasis. Recent reports suggest that silent mating-type information regulation 2 homologue 1 (sirtuin1; SIRT1) enhances the function of cortactin and promotes cell migration. We investigated SIRT1 and cortactin expression in 144 invasive non-small cell lung cancers (NSCLC) and 19 adenocarcinomas in situ (AIS) by immunohistochemistry and evaluated their clinicopathological significance in NSCLC. Positive SIRT1 and cortactin expression was observed in 67% (96 of 144) and 58% (84 of 144) of patients with invasive NSCLC, respectively. SIRT1 and cortactin expression was significantly associated with unfavorable clinicopathological factors, including high pathological T stage, lymph node metastasis, and advanced tumor invasion (AIS vs. invasive adenocarcinoma). Cortactin was significantly associated with high pathological T stage and lymph node metastasis in SIRT1-positive tumors. Cytoplasmic SIRT1 was significantly associated with high pathological T stage and large tumor size compared to that of nuclear SIRT1. Large tumor size, high pathological T stage, lymph node metastasis, and cytoplasmic SIRT1 expression were significantly associated with shorter overall survival in a univariate analysis. Our findings suggest that SIRT1 and cortactin may play a role in the progression of NSCLC and may cooperate during tumor progression in NSCLC.

Acetylation status of P53 and the expression of DBC1, SIRT1, and androgen receptor are associated with survival in clear cell renal cell carcinoma patients

Aims: Recently, the important role of silent mating type information regulation 2 homolog 1 (SIRT1) and deleted in breast cancer 1 (DBC1) in human cancer has been extensively studied and their role has been closely related with the control of P53 and androgen receptor (AR) functions. However, their role in clear cell renal cell carcinoma (CRCC) is still unknown. Methods: We evaluated the expression of SIRT1, P53, acetylated-P53, DBC1 and AR and their prognostic significance in 200 CRCC patients. Results: The expression of SIRT1, P53, DBC1, and AR significantly correlated with each other and all of them predicted shorter overall survival (OS), relapse-free survival (RFS), and cancer-specific survival (CSS). In contrast, the expression of acetylated-P53 predicted favourable OS, RFS, and CSS. Combined expression pattern of acetylated-P53 and P53 (Ac-P53/P53) also closely correlated with survival of CRCC patients. Multivariate analysis revealed DBC1, acetylated-P53, and Ac-P53/P53 expression as independent prognostic indicators for OS and RFS, and Ac-P53 expression as an independent prognostic indicator for CSS. Conclusions: This study demonstrates that the acetylation status of P53 and the expression of SIRT1, DBC1, and AR could be new prognostic indicators for CRCC and suggest that SIRT1-P53 and DBC1-AR related pathways could be new therapeutic targets for the treatment of CRCC.