두경부 편평상피세포암에서 종양억제유전자들의 변이

송시연(Si Youn Song),박강식(Kang Shik Park),배창훈(Chang Hoon Bai) 대한두경부종양학회 2004 대한두경부 종양학회지 Vol.20 No.2

Objectives: Head and neck squamous cell carcinoma (HNSCC) is the most common head and neck malignant tumor. The molecular genetic changes involving both oncogenes and tumor suppressor genes are known to be involved in head and neck squamous cell carcinogenesis, but the roles of the known tumor suppressor genes in carcinogenesis are not fully elucidated. The objectives of this study are to demonstrate the genetic alterations including the loss of heterozygosity (LOH) , amplification, and microsatellite instability of known tumor suppressor genes in HNSCC and to evaluate the relationship between genetic alterations of tumor suppressor genes and clinicopathologic features. Materials and Methods: Genetic alterations of 10 micro satellite markers of the 6 known tumor suppressor genes (APC, EXT1, DPC4, p16, FHIT, and PTEN) were analysed by DNA-PCR in paraffin-embedded histologically confirmed HNSCC specimens. Results: The genetic alterations of tumor suppressor genes were found frequently. Among the genetic alterations, LOH was most frequently found one. LOH was found frequently in APC (45.4%), EXT1 (36.4%), DPC4 (54.5%), and p16 (50%), but not found in FHIT. Also, the author found that abnormalities of APC gene was related to cervical lymph node metastasis and recurrence and that abnormalities of EXT1 gene were coexisted with those of APC gene or DPC4 gene. But these coexistences had no correlation with clinical features. Conclusion: These results suggested that APC, EXT1, p16, and DPC4 genes might play important roles and multiple tumor suppressor genes may participate dependently or independently in the carcinogenesis of HNSCC. These results also suggested that APC gene might relate to prognosis.

유방의 침윤성 관암에서 주요 종양 억제유전자의 이형접합 소실

박찬흔 한국유방암학회 2007 Journal of breast cancer Vol.10 No.1

Purpose: Breast cancer is one of the most frequent malignant tumors in Korea. The major tumor suppressor genes (TSGs) such as p16, Rb, E-cadherin and p53 may play important roles in cell cycle regulation, apoptosis and the regulation of the expression of other genes as well as tumor suppression. Microsatellite alteration such as loss of heterozygosity (LOH) have been reported to be a novel mechanism of carcinogenesis and a useful prognostic factor for many malignant tumors. Also, LOH is also known to be related with allelic loss of various TSGs. This study evaluated LOH of 4 TSGs in invasive ductal carcinomas (IDCs) and we correlated these results with the clinicopathological factors. Methods: LOH analysis was carried out using a polymerase chain reaction with 12 polymorphic microsatellite markers of 4 TSGs in 50 surgically resected tumors and their non-tumorous counterparts. Results: There was no detectable LOH in the normal tissue. LOH was detected in 86% of the 50 cases of IDCs. LOH was detected on al chromosomes and this showed a statistical difference between benign tumor and malignant tumor. LOH of p16, Rb, E-cadherin and p53 TSGs was detected in 36%, 26%, 54% and 60% of the tumors, respectively. LOH of the p16 and Rb genes was inversely correlated with tumor grade 1. The low rate of detecting LOH on the E-cadherin gene was noted in T1 tumor and stage I disease. LOH of the p53 gene correlated well with the tumor size and stage. The LOH-High results correlate well with the tumor size and stage and the LOH-High results are similar to those of the p53 gene LOH. Conclusion: These results suggest that LOH of the 4 major TSGs may contribute to the development and invasion of IDCs. Also, the combined use of various LOH markers may help in deciding the prognosis of IDCs.

Quantification of Tumor Suppressor mRNA Expression by Poly-competitive RT-PCR Using a TS-IS that Contained Multiple Internal Competitors

Hee-Jung Jung,Ji Hyung Chae,김호근,JeonHan Park,Jong Soo Lee,Woong Hwan Choi,김철근 한국분자세포생물학회 2002 Molecules and cells Vol.13 No.3

Despite the recent introduction of real-time PCR methods and cDNA microarrays, competitive PCR techniques continue to play an important role in nucleic acid quantification because of the significantly lower cost of equipment and consumables. In this study, we developed a construct, termed tumor suppressor- internal standard (TS-IS) that produced polycompetitive RNA templates as an internal standard to quantify cellular RNA concentration of tumor suppressor genes. This construct is composed of not only sets of primers for detecting the expression of several tumor suppressor genes (such as pRB, p16INK4A, p15INK4B, p14ARF, p53, and p21WAF1), but also HPRT as an endogenous marker. Using an internal standard RNA that was synthesized from the TS-IS construct, we were able to establish optimized conditions for the quantification of tumor suppressor genes with minimal amounts (50 ng) of cellular RNA. In addition, the usefulness of this method was confirmed by analyzing the expression levels of tumor suppressor genes in fourteen hepatoma cell lines as a model. The TS-IS assay that we used was inexpensive and a widely applicable method that permitted the reliable and accurate quantification of tumor suppressor genes.

Frequent epigenetic inactivation of hSRBC in gastric cancer and its implication in attenuated p53 response to stresses

Lee, Jin-Hee,Byun, Do-Sun,Lee, Min-Goo,Ryu, Byung-Kyu,Kang, Min-Ju,Chae, Kwon-Seok,Lee, Kil Yeon,Kim, Hyo-Jong,Park, Heonyong,Chi, Sung-Gil Wiley Subscription Services, Inc., A Wiley Company 2008 International journal of cancer: Journal internati Vol.122 No.7

<P>hSRBC is a putative tumor suppressor located at 11p15.4, at which frequent genomic loss has been observed in several human malignancies. To explore the candidacy of hSRBC as a suppressor of gastric tumorigenesis, we analyzed the expression and mutation status of hSRBC in gastric tissues and cell lines. hSRBC transcript was expressed in all normal and benign tumor tissues examined, but undetectable or very low in 73% (11/15) cancer cell lines and 41% (46/111) primary tumors. Loss or reduction of hSRBC expression was tumor-specific and correlated with stage and grade of tumors. While allelic loss or somatic mutations of the gene were infrequent, its expression was restored in tumor cells by 5-aza-2′-deoxycytidine treatment and aberrant hypermethylation of 23 CpG sites in the promoter region showed a tight association with altered expression. Transient or stable expression of hSRBC led to a G<SUB>1</SUB> cell cycle arrest and apoptosis of tumor cells, and strongly suppresses colony forming ability and xenograft tumor growth. In addition, hSRBC elevated apoptotic sensitivity of tumor cells to genotoxic agents, such as 5-FU, etoposide and ultraviolet. Interestingly, hSRBC increased the protein stability of p53 and expression of p53 target genes, such as p21<SUP>Waf1</SUP>, PUMA and NOXA, while hSRBC-mediated cell cycle arrest and apoptosis were abolished by blockade of p53 function. Our findings suggest that hSRBC is a novel tumor suppressor whose epigenetic inactivation contributes to the malignant progression of gastric tumors, in part, through attenuated p53 response to stresses. © 2007 Wiley-Liss, Inc.</P>

Tumor-Suppression Mechanisms of Protein Tyrosine Phosphatase O and Clinical Applications

Kang, Man-Man,Shan, Shun-Lin,Wen, Xu-Yang,Shan, Hu-Sheng,Wang, Zheng-Jun Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.15

Tyrosine phosphorylation plays an important role in regulating human physiological and pathological processes. Functional stabilization of tyrosine phosphorylation largely contributes to the balanced, coordinated regulation of protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs). Research has revealed PTPs play an important suppressive role in carcinogenesis and progression by reversing oncoprotein functions. Receptor-type protein tyrosine phosphatase O (PTPRO) as one member of the PTPs family has also been identified to have some roles in tumor development. Some reports have shown PTPRO over-expression in tumors can not only inhibit the frequency of tumor cell division and induce tumor cell death, but also suppress migration. However, the tumor-suppression mechanisms are very complex and understanding is incomplete, which in some degree blocks the further development of PTPRO. Hence, in order to resolve this problem, we here have summarized research findings to draw meaningful conclusions. We found tumor-suppression mechanisms of PTPRO to be diverse, such as controlling G0/G1 of the tumor cell proliferation cycle, inhibiting substrate phosphorylation, down-regulating transcription activators and other activities. In clinical anticancer efforts, expression level of PTPRO in tumors can not only serve as a biomarker to monitor the prognosis of patients, but act as an epigenetic biomarker for noninvasive diagnosis. In addition, the re-activation of PTPRO in tumor tissues, not only can induce tumor volume reduction, but also enhance the susceptibility to chemotherapy drugs. So, we can propose that these research findings of PTPRO will not only support new study ideas and directions for other tumor-suppressors, importantly, but also supply a theoretical basis for researching new molecular targeting agents in the future.

Proteome profile changes that are differentially regulated by lipid and protein phosphatase activities of tumor suppressor PTEN in PTEN-expressing U-87 MG human glioblastoma cells

Shim, Jung Hye,Kim, Yu Sam,Bahk, Young Yil WILEY-VCH 2006 Proteomics Vol. No.

<P>The phosphatase and tensin homolog tumor suppressor (PTEN) belongs to a class of “gatekeeper” tumor suppressors together with p53, retinoblastoma and adenomatous polyposis. It is considered one of the most important tumor suppressors in the post p53 era. Previously to identify the molecules involved in the signaling network regulated by PTEN using proteomic tools, we reported global proteome profiles at different time points using the PTEN inducible NIH3T3 cells (Kim, S.-y., Kim, Y. S., Bahk, Y. Y., Mol. Cells 2003, 15, 396–405). However, the system had a critical limitation that NIH3T3 cell has endogenous wild-type PTEN and, thus to be exact, the induced PTEN could not give the answer about the real physiological roles of this tumor suppressor. Here, to find out PTEN-related protein network we have established various PTEN (wild-type, an activity inert C124G, and a lipid phosphatase deficient G129E)-expressing cell clones in U-87 MG human glioblastoma cells lacking detectable PTEN as a result of genetic lesions. In this biological context, we compared their morphological and expression patterns, and proteome images of each PTEN-expressing cell clone by 2-DE followed by identification with MALDI-TOF MS. We obtained some pieces of evidence that morphological change by PTEN expression is mediated by its protein phosphatase activity and their growth rate by the lipid phosphatase activity. The proteomic approaches showed that 30 proteins possibly correlated with PTEN's protein phosphatase activity (13 down-regulated and 17 up-regulated) and 20 with the lipid phosphatase activity (14 down-regulated and 6 up-regulated) were identified. Taken together, we conclude that the comparative analysis of proteome from various PTEN-expressing cells has yielded interpretable data to elucidate the protein network directly and/or indirectly caused by individual phosphatase activities of PTEN in vivo.</P>

NSAID Activated Gene (NAG-1), a Modulator of Tumorigenesis

Eling, Thomas E.,Baek, Seung-Joon,Shim, Min-sub,Lee, Chang-Ho Korean Society for Biochemistry and Molecular Biol 2006 Journal of biochemistry and molecular biology Vol.39 No.6

The NSAID activated gene (NAG-1), a member of the TGF-$\beta$ superfamily, is involved in tumor progression and development. The over-expression of NAG-1 in cancer cells results in growth arrest and increase in apoptosis, suggesting that NAG-1 has anti-tumorigenic activity. This conclusion is further supported by results of experiments with transgenic mice that ubiquitously express human NAG-1. These transgenic mice are resistant to the development of intestinal tumors following treatment with azoxymethane or by introduction of a mutant APC gene. In contrast, other data suggest a pro-tumorigenic role for NAG-1, for example, high expression of NAG-1 is frequently observed in tumors. NAG-1 may be like other members of the TGF-$\beta$ superfamily, acting as a tumor suppressor in the early stages, but acting pro-tumorigenic at the later stages of tumor progression. The expression of NAG-1 can be increased by treatment with drugs and chemicals documented to prevent tumor formation and development. Most notable is the increase in NAG-1 expression by the inhibitors of cyclooxygenases that prevent human colorectal cancer development. The regulation of NAG-1 is complex, but these agents act through either p53 or EGR-1 related pathways. In addition, an increase in NAG-1 is observed in inhibition of the AKT/GSK-$3{\beta}$ pathway, suggesting NAG-1 alters cell survival. Thus, NAG-1 expression is regulated by tumor suppressor pathways and appears to modulate tumor progression.

Analysis of the Expression and Regulation of PD-1 Protein on the Surface of Myeloid-Derived Suppressor Cells (MDSCs)

남소림,이아람,임지현,임종석 한국응용약물학회 2019 Biomolecules & Therapeutics(구 응용약물학회지) Vol.27 No.1

Myeloid-derived suppressor cells (MDSCs) that are able to suppress T cell function are a heterogeneous cell population frequently observed in cancer, infection, and autoimmune disease. Immune checkpoint molecules, such as programmed death 1 (PD-1) expressed on T cells and its ligand (PD-L1) expressed on tumor cells or antigen-presenting cells, have received extensive attention in the past decade due to the dramatic effects of their inhibitors in patients with various types of cancer. In the present study, we investigated the expression of PD-1 on MDSCs in bone marrow, spleen, and tumor tissue derived from breast tumor-bearing mice. Our studies demonstrate that PD-1 expression is markedly increased in tumor-infiltrating MDSCs compared to expression in bone marrow and spleens and that it can be induced by LPS that is able to mediate NF-κB signaling. Moreover, expression of PD-L1 and CD80 on PD-1+ MDSCs was higher than on PD-1– MDSCs and proliferation of MDSCs in a tumor microenvironment was more strongly induced in PD-1+ MDSCs than in PD-1– MDSCs. Although we could not characterize the inducer of PD-1 expression derived from cancer cells, our findings indicate that the study on the mechanism of PD-1 induction in MDSCs is important and necessary for the control of MDSC activity; our results suggest that PD-1+ MDSCs in a tumor microenvironment may induce tumor development and relapse through the modulation of their proliferation and suppressive molecules.

The Expressions of E2F1 and p53 in Gastrointestinal Stromal Tumors and Their Prognostic Significance

권미정,남은숙,박혜림,신형식,이종석,박찬흔,신운건,조성진 대한병리학회 2009 Journal of Pathology and Translational Medicine Vol.43 No.3

Background : E2F1 plays a critical role in the G1-to-S phase transition by inducing various genes that encode S phase-activating proteins and that modulate such diverse cellular functions as DNA synthesis, mitosis and apoptosis. The purpose of this study was to assess the E2F1 expression in relation to the clinicopathologic parameters and other tumor markers in gastrointestinal stromal tumors. Methods : Immunohistochemical stainings for obtaining the E2F1, p53, and Ki-67 labeling indices were performed on a tissue microarray of 72 gastrointestinal stromal tumor specimens. The clinicopathologic parameters that were analyzed including the risk grade system by Miettinen et al. and the disease-free survival (DFS) rate. Results : 1) An E2F1 expression was correlated with a larger tumor size, a p53 expression and a shorter period of DFS (p=0.014, p=0.007, and p=0.039). 2) A p53 expression was significantly associated with a high risk grade, a larger tumor size, high mitotic counts and a shorter period of DFS (p=0.003, p=0.044, p<0.001, and p<0.0001). 3) A high-risk grade and the epithelioid type were significantly associated with a shorter period of DFS (p=0.0006 and p=0.0008). Conclusions : E2F1, as well as p53, may be a potentially novel independent prognostic factor for predicting a worse outcome for those patients suffering with Gastrointestinal stromal tumors.

Loss of Heterozygosities in Five Tumor Suppressor Genes (FHIT Gene, p16, pRb, E-Cadherin and p53) in Thyroid Tumors

김진환,최규영,이동진,노영수,조성진 대한이비인후과학회 2014 Clinical and Experimental Otorhinolaryngology Vol.7 No.1

Objectives. To evaluate the loss of heterozygosities (LOH) of chromosomes 3p14 (FHIT gene), 9p21 (p16), 13q21 (pRb), 6q22 (E-cadherin) and 17p13 (p53) in various thyroid tumors. Methods. Eighty thyroid tumor cases (20 follicular adenomas, 10 follicular carcinomas, and 50 papillary carcinomas) have been analyzed for the presence of LOH in chromosomes 3p14, 9p21, 13q21, 6q22, and 17p13 allelic loss, using mic- rosatellite markers and DNA obtained from formalin-fixed paraffin-embedded archival tissues. Results. LOH on 3p14 was found in 10.5%, 33.3%, and 30.4% of follicular adenomas, follicular carcinomas, and papillary carcinomas, respectively. LOH on 9p21 was detected in 6%, 44.4%, and 47.8%, respectively. LOH on pRb gene was found in 5.3%, 20.0%, and 35.4%, respectively. LOH on E-cadherin gene was found in 5.3%, 22.2%, and 43.8%, respectively. LOH on 17p13 was detected in 0%, 40%, and 45.8%, respectively. LOH in FHIT gene, p16, pRb, E- cadherin, and p53 genes were more frequently identified in follicular carcinoma and papillary carcinoma than in fol- licular adenoma. Conclusion. LOH results of the five tumor suppressor genes (FHIT gene, p16, pRb, E-cadherin, and p53) showed statistical differences between benign tumor and malignant tumor. Among papillary carcinoma, LOH in p16, E-cadherin and p53 genes well correlated with poorly differentiated grade, and LOH of E-cadherin was associated with lymph node metastasis.