위암의 Phosphorylated Akt 단백질의 발현

이석형,이종우,박원상,이정용,유남진,김수영,Lee Sug Hyung,Lee Jong Woo,Park Won Sang,Lee Jung Young,Yoo Nam Jin,Kim Su Young 대한위암학회 2003 대한위암학회지 Vol.3 No.2

Purpose: Mounting evidence suggests that alterations of Akt/protein kinase B (PKB) play an important role in tumorigenesis. Phosphorylated Akt regulates many of the key effector molecules involved in apoptosis, angiogenesis, and cell-cycle progression during tumorigenesis. The expression of phosphorylated Akt has been described in some human malignancies, but not in primary human gastric cancer. The purpose of this study was to explore the expression status of phosphorylated Akt protein in gastric carcinomas. Materials and Methods: In the current study, we analyzed the expression of phosphorylated Akt protein in 60 advanced gastric adenocarcinomas by using immunohistochemistry and a tissue microarray approach. Results: Immunopositivity (defined as $\geq\30\%$) was observed for the phosphorylated Akt in 42 ($70\%$) of the 60 cancers. Normal gastric mucosal cells showed no or weak expression of phosphorylated Akt protein. Conclusion: Taken together, these results indicate that Akt is frequently activated in gastric adenocarcinoma cells and suggest that phosphorylayed Akt may play a role in the development of human gastric adenocarcinomas.

위암의 Fas-associated Death Domain Protein 단백질의 발현

이석형,이종우,박원상,이정용,유남진,Lee, Sug-Hyung,Lee, Jong-Woo,Park, Won-Sang,Lee, Jung-Young,Yoo, Nam-Jin 대한위암학회 2003 대한위암학회지 Vol.3 No.2

Purpose: Evidence exists that dysregulation of apoptosis is involved in the pathogenesis of cancer development. Fasassociated death domain (FADD) protein, an adaptor protein of death receptors, is a critical regulatory component of the extrinsic cell- death pathway that exerts its pro-apoptotic effect upon binding with death receptors. Expression of the FADD protein has not been reported in stomach cancer. The aim of this study was to explore the expression status of the FADD protein in stomach cancers. Materials and Methods: In the current study, we analyzed the expression of the FADD protein in 60 advanced stomach cancer by using immunohistochemistry and a tissue microarray approach. Results: Immunopositivity (defined as $\geq\30\%$) was observed for the FADD protein in 23 ($38\%$) of the 60 cancers. Normal gastric mucosal cells showed expression of the FADD protein. Conclusion: Taken together, these results indicate that decreased expression of the FADD protein is a frequent event in stomach cancers and suggest that to avoid apoptosis, stomach cancer cells in vivo may need loss of FADD expression, which might contribute to tumor development.

위암의 BAD 단백질의 발현

유남진,이종우,박원상,이정용,이석형,Yoo, Nam-Jin,Lee, Jong-Woo,Park, Won-Sang,Lee, Jung-Young,Lee, Sug-Hyung 대한위암학회 2003 대한위암학회지 Vol.3 No.2

Purpose: Evidence exists that dysregulation of apoptosis is involved in the pathogenesis of cancer development. The Bcl-$x_{L}$/Bcl-2-associated death promoter (BAD), a member of the Bcl-2 family, is a critical regulatory component of the intrinsic cell-death pathway that exerts its pro-apoptotic effect upon heterodimerization with anti-apoptotic proteins Bcl-2 and Bcl-$X_{L}$. Expression of the BAD protein has been reported in several cancer types, but not in stomach cancer. The aim of this study was to explore the expression status of the BAD protein in gastric carcinomas. Materials and Methods: In the current study, we analyzed the expression of the BAD protein in 60 advanced gastric adenocarcinomas by using immunohistochemistry and a tissue microarray approach. Results: Immunopositivity (defined as $\geq\30\%$) was observed for the BAD protein in 57 ($95\%$) of the 60 cancers. Normal gastric mucosal cells showed weaker expressions of the BAD protein than gastric carcinomas. Conclusion: Taken together, these results suggest that stomach cancer cells in vivo may need BAD protein expression for apoptosis. Also, the higher expression of the BAD protein in stomach cancer cells than in normal gastric mucosal cells suggests that apoptosis might be easily triggered in susceptible stomach cancer cells, thereby producing selective pressure to make more apoptosis-resistant cells during tumor development.

위암에서 발견된 돌연변이형 Fas 단백의 기능적 결함

박원상,조용구,김창재,박조현,김영실,김수영,남석우,이석형,유남진,이정용,Park Won Sang,Cho Young Gu,Kim Chang Jae,Park Cho Hyun,Kim Young Sil,Kim Su Young,Nam Suk Woo,Lee Sug Hyung,Yoo Nam Jin,Lee Jung Young 대한위암학회 2003 대한위암학회지 Vol.3 No.4

Purpose: The balance between cell proliferation and apoptosis is crucial for homeostatic maintenance in a cell population. Decreased apoptosis or uncontrolled proliferation can lead to cancer. The Fas receptor signal through a cytoplasmic death domain is very important in the apoptotic pathway. To identify the effect of the death domain of the Fas gene in the development and/or progression of gastric cancer, we examined the apoptotic potential of five known Fas mutants detected in gastric cancers. Materials and Methods: A wild-type Fas gene was cloned with cDNA from normal liver tissue and full length Fas was sequenced. Mutants of the gene were generated with sitedirected mutagenesis by using the wild-type gene and specific primers. Wild- and mutant-type genes were transfected to HEK293 cells. Forty-eight hours after transfection the cells were stained with DAPI and cell death was counted under fluorescent microscopy. Results: In wild-type Fas-transfected cells, the percentage of apoptotic cells was $85.9\pm3.6\%$, and significant cell death and classic morphologic signs of apoptosis were observed. However, the percentages of apoptotic cells transfected with N239D, E240G, D244V, and R263H of tumor-derived mutant Fas were $29.5\pm2.08\%,\;28.5\pm3.34\%,\;25.225\pm2.06\%,\;and\;36.625\pm4.49\%$, respectively. Conclusion: These results suggest that inactivation of Fas caused by mutations in the death domain of the Fas gene may be one of the possible escape mechanisms against Fas-mediated apoptosis and that inactivating mutation of the Fas may contribute to the development or progression of gastric cancers.

한국인 위암에서 KLF6 단백 발현 양상

조용구,김창재,박조현,김수영,남석우,이석형,유남진,이정용,박원상,Cho Young Gu,Kim Chang Jae,Park Cho Hyun,Kim Su Young,Nam Suk Woo,Lee Sug Hyung,Yoo Nam Jin,Lee Jung Young,Park Won Sang 대한위암학회 2005 대한위암학회지 Vol.5 No.1

목적: KLF6는 모든 조직에서 발현되고 있는 zinc finger를 가진 종양억제유전자로 인체 여러 암에서 불활성화되어 있다. 연구자들은 KLF6 단백의 발현 변화가 위암의 발생에 관여하는 지를 알아보고자 하였다. 대상 및 방법: 85예의 파라핀 포매된 위암조직에서 암세포들으 각각 3군데에서 펀치하여 새로운 파라핀 블록으로 옮겨 위암의 tissue microarray를 제작하였다. Tissue microarray 절편에서 KLF6 단백에 대한 항체로 면역화학염색을 실시한 후 발현 양상을 병리 지표들인 조직학적 소견, 침습 정도, 림프절 전이 및 복막파종 등과의 연관성을 조사하였다. 결과: KLF6 단백은 위점막의 표면과 소와 상피세포에서 주로 발현되고 있었고 85예 중 28예($28.9\%$)에서 발현 소실이 관찰되었다. 흥미롭게도 KLF6 단백의 발현 소실은 림프절 전이와 통계적으로 연관성이 있었으나 조직학적 소견, 침습 정도와 복막파종과는 연관성이 없었다. 결론: 이러한 소견들은 KLF6 단백의 발현 소실이 위장관 상피세포의 비정상적인 성장과 분화를 유도하고 위암의 발생 및 진행에 관여한다는 것을 의미한다. Purpose: KLF6, a member of the KLF family, is a ubiquitous zinc finger tumor suppressor protein that is mutated in several human cancers. Our aim was to determine whether the expression pattern of KLF6 might be associated with gastric cancer development and, if so, to determine to which pathologic parameter it is linked. Materials and Methods: For the construction of the gastric cancer tissue microarray, 85 paraffin-embedded tissues containing gastric cancer areas were cored 3 times and transferred to the recipient master block. The expression pattern of KLF6 was examined on tissue microarray slides by using immunohistochemistry and was compared with pathologic parameters, including histologic type, depth of invasion, lymph node metastasis, and peritoneal dissemination. Results: The KLF6 protein was expressed on superficial and foveolar epithelial cells in the gastric mucosa. We found loss of KLF6 expression in 28 ($32.9\%$) of the 85 gastric cancer tissues. There was a significant correlation between loss of KLF6 expression and lymph-node metastasis. However, other pathologic parameters, such as histologic type, depth of invasion, and peritoneal dissemination, were not statistically associated with loss of KLF6 expression. Conclusion: Our findings suggest that loss of KLF6 expression may contribute to abnormal regulation of gastrointestinal epithelial cell growth and differentiation and to the development and/or progression of Korean gastric cancer.

위암에서의 고사유발성 Bcl-2 Family의 돌연변이에 관한 연구

유남진,이종우,송영화,김홍석,박원상,이정용,이석형,Yoo Nam Jin,Lee Jong Woo,Soung Young Hwa,Kim Hong Sug,Park Won Sang,Lee Jung Young,Lee Sug Hyung 대한위암학회 2003 대한위암학회지 Vol.3 No.2

Purpose: Evidence exists that dysregulation of Bcl-2 family members is involved in the pathogenesis of cancer development. The aim of this study was to explore whether the somatic mutation of proapoptotic Bcl-2 member genes, one of the mechanisms that prolong the survival of cancer cells, is involved in gastric carcinogenesis. Materials and Methods: In the current study, to detect somatic mutations of the DNA sequences encoding the Bcl-2 homology 3 (BH3) domain of the human BAD, BIM, BIK, and Bcl-G genes in 60 advanced gastric adenocarcinomas, we used the polymerase chain reaction (PCR), single strand conformation polymorphism (SSCP), and DNA sequencing. Results: The SSCP analysis revealed no mutations in the coding regions of the BH3 domain in the cancers. Conclusion: The data presented here indicate that proapoptotic Bcl-2 member genes, BAD, BIM, BIK, and Bcl-G, may not be mutated in human gastric carcinomas and suggest that these genes might be altered by mechanisms other mechanisms somatic mutation.

Interleukin-1$\beta$ 및 Interleukin-1 Receptor Antagonist의 유전적 다형성과 한국인 위암과의 연관 관계

박직영,조용구,김창재,박용규,김영실,박조현,이석형,유남진,이정용,박원상,Park Jik Young,Cho Young Gu,Kim Chang Jae,Park Yong Kyu,Kim Young Sil,Park Cho Hyun,Lee Sug Hyung,Yoo Nam Jin,Lee Jung Young,Park Won Sang 대한위암학회 2002 대한위암학회지 Vol.2 No.3

Purpose: Interleukin 1$\beta$ (IL-1$\beta$) polymorphisms are associated with hypochlorhydria, atrophic gastritis, and increased risk of gastric cancer in Caucasians. We tried to determine whether the IL-1.. and IL-1 receptor antagonist (IL-1 RN) genetic polymorphisms contribute to the development of gastric cancer and the specific type of gastritis in Korean. Materials and Methods: The study population was comprised of 128 gastric cancer patients with histologically proven carcinoma and 63 normal healthy individuals. Sixty-eight carcinomas were of intestinal-type and sixty tumors were of diffuse-type. No patient had a familial gastric cancer history. The 511 bp and 31 bp polymorphisms in the IL-1.. were genotyped by polymerase chain reaction (PCR)-restriction fragment length polymorphism. The polymorphism of the IL-1 RN was analyzed with variable number tandem repeat after PCR. Results: The genotype of 511C/-31T of IL-1$\beta$ and allele 1 of IL-1 RN was dominant in the present subjects. The allelic frequencies of the C allele IL-1$\beta$, which is a high risk genotype for gastric cancer, were 0.551 and 0.429 in gastric cancer and normal controls, respectively. Statistically, significant difference in allelic frequencies of three polymorphic sites between gastric cancer patients and normal controls, and between intestinal-type and diffuse-type was not observed. Conclusions: These results suggest that the polymorphisms of IL-1$\beta$ and IL-1 RN may not contribute to the development of Korean gastric caner and that other endogenous or exogenous factors will be important for gastric carcinogenesis.

한국인 위암에서 KLF4 단백 발현 양상

송재휘,조용구,김창재,박조현,김수영,남석우,이석형,유남진,이정용,박원상,Song, Jae-Hwi,Cho, Yong-Gu,Kim, Chang-Jae,Park, Cho-Hyun,Kim, Su-Young,Nam, Suk-Woo,Lee, Sug-Hyung,Yoo, Nam-Jin,Lee, Jung-Young,Park, Won-Sang 대한위암학회 2005 대한위암학회지 Vol.5 No.3

목적: Zinc finger를 가진 KLF4는 위장관 상피세포의 항상성 유지에 중요한 역할을 하는 종양억제유전자이다. 연구자들은 KLF4 단백의 발현 변화가 위암의 발생에 관여하는지를 파악하고 위암의 병리 지표들과 연관성이 있는지를 알아보고자 하였다. 대상 및 방법: 84예의 파라핀 포매된 위암조직에서 암세포들을 각각 3군데에서 펀치하여 새로운 파라핀 블록으로 옮겨 위암의 tissue microarray를 제작하였다. Tissue microarray 절편에서 KLF4 단백에 대한 항체로 면역화학염색을 실시한 후 발현 양상을 병리 지표들인 조직학적 소견, 침습 정도, 림프절 전이 및 복막파종 등과의 연관성을 조사하였다. 결과: KLF4 단백은 위점막의 표면과 소와 상피세포의 세포질과 핵에서 주로 발현되고 있었고 조사된 위암 84예 중 43예(51.2%)에서 발현이 현저히 저하되어 있거나 소실되어 있었다. 이러한 KLF4 단백의 발현 소실은 조직학적 소견, 침습 정도, 림프절 전이 및 복막파종과는 통계적으로 연관성이 없었다. 결론: 이러한 연구 결과는 KLF4 단백의 발현 소실이 위장관 상피세포의 비정상적인 성장과 분화를 유도하고 위암의 발생 초기에 관여한다는 것을 의미한다. Purpose: KLF4, a member of the KLF family, is a zinc finger tumor suppressor protein that is critical for gastric epithelial homeostasis. Our aim was to determine whether the altered expression of KLF4 might be associated with gastric cancer development and, if so, to determine to which pathologic parameter it is linked. Materials and Methods: For the construction of the gastric cancer tissue microarray, 84 paraffin-embedded tissues containing gastric cancer areas were cored 3 times and transferred to the recipient master block. The expression pattern of KLF4 was examined on tissue microarray slides by using immunohistochemistry and was compared with pathologic parameters, including histologic type, depth of invasion, lymph node metastasis, and peritoneal dissemination. Results: The KLF4 protein was expressed in cytoplasm and nucleus of superficial and foveolar epithelial cells in the normal gastric mucosa. We found markedly reduced or loss of KLF4 expression in 43 (51.2%) of the 84 gastric cancer tissues. There was no significant correlation between KLF4 expression and pathologic parameters, including histologic type, depth of invasion, lymph node metastasis and peritoneal dissemination. Conclusion: Our findings suggest that altered expression of KLF4 may contribute to abnormal regulation of gastrointestinal epithelial cell growth and differentiation and to the development of Korean gastric cancer, as an early event.

위암에서 여러 종양억제유전자 부위의 이형접합성 소실과 현미 부수체 불안정성

조용구,김창재,박조현,김영실,김수영,남석우,이석형,유남진,이정용,박원상,Cho Young Gu,Kim Chang Jae,Park Cho Hyun,Kim Young Sil,Kim Su Young,Nam Suk Woo,Lee Sug Hyung,Yoo Nam Jin,Lee Jung Young,Park Won Sang 대한위암학회 2003 대한위암학회지 Vol.3 No.4

Purpose: The aim of this study was to investigate the frequency of loss of heterozygosity and the microsatellite instability at multiple tumor suppressor gene loci in gastric adenocarcinomas. Materials and Methods: Loss of heterozygosity and the microsatellite instability at several tumor suppressor gene loci were analyzed in 29 primary gastric carcinomas by using microdissection and the polymerase chain reaction. Results: Twenty-three ($79\%$) of the 29 cases demonstrated loss of heterozygosity at one or more loci. The frequency of loss of heterozygosity at the p53 locus was the highest ($63\%$) and those at the VHL, APC, p16, Rb, MEN1, BRCA1, DPC4, 3p21, and 16p13 region were $41\%,\;36\%,\;19\%,\;29\%,\;33\%,\;26\%,\;21\%,\;32\%,\;and\;11\%$, respectively. Compared with histological type, loss of heterozygosity was more common in diffuse-type gastric cancer (P<0.01). Interestingly, 9 of 10 tumors with allelic deletion at the p53 locus showed loss of heterozygosity at other tumor suppressor gene loci. The microsatellite instability was also detected in 6 ($20\%$) of the 29 cases at one or more loci. Conclusion: These data suggest that frequent loss of heterozygosity and the microsatellite instability at multiple tumor suppressor genes might be required for the development and the progression of gastric carcinomas and that p53 allelic loss may be the most frequent event in the development of gastric carcinomas.

현미부수체 불안정성을 동반한 위암에서 Chk1 유전자의 돌연변이

이종흔,조용구,송재휘,박조현,김수영,남석우,이석형,유남진,이정용,박원상,Lee, Jong-Heun,Cho, Young-Gu,Song, Jae-Whie,Park, Cho-Hyun,Kim, Su-Yeong,Nam, Suk-Woo,Lee, Sug-Hyung,Yoo, Nam-Jin,Lee, Jung-Young,Park, Won-Sang 대한위암학회 2005 대한위암학회지 Vol.5 No.4

목적: Chk1 kinase는 세포 내 DNA 손상에 따른 세포주기의 저지에 관여하며 G2/M checkpoint에서 중요한 역할을 한다. 연구자들은 위암에서 현미부수체 불안정성과 Chk1 유전자의 격자이동 돌연변이와의 연관성을 알아보고자 하였다. 대상 및 방법: 95예의 위암조직에서 레이저를 이용하여 정상과 암세포를 미세절제한 다음 6개의 현미부수체 표식자를 이용하여 현미부수체 불안정성을 조사하였다. 현미부수체 불안정이 있는 예에서 single strand conformational polymorphism과 염기서열 분석으로 Chk1 유전자의 격자이동 돌연변이를 조사하였다. 결과: 현미부수체 불안정성은 95예의 위암 중 19예 (20%)에서 발견되었는데 고빈도와 저빈도의 현미부수체 불안정성은 각각 13예와 6예였다. 고빈도의 현미부수체 불안정성이 있는 13예 중 2예에서 Chk1 유전자의 격자이동 돌연변이가 발견되었는데 이는 아미노산의 격자이동으로 truncated 단백을 형성하였다. 결론 : 이러한 결과는 현미부수체 불안정성은 Chk1 유전자의 격자이동 돌연변이를 유도하여 세포주기 조절 기능을 상실하게 함으로써 위암의 발생에 관여한다는 것을 의미한다. Purpose: The protein kinase Chk1 is required for cell cycle arrest in response to DNA damage and is shown to play an important role in the G2/M checkpoint. The aim of this study was to investigate the relationship between microsatellite instability and frameshift mutation of the Chk1 gene in gastric cancers. Materials and Methods: The microsatellite instability was analyzed in 95 primary gastric carcinomas by using microdissection and 6 microsatellite markers. We also peformed single strand conformational polymorphism and sequencing to detect frameshift mutation of the Chk1 gene. Results: We found positive microsatellite instability in 19 (20%) of the 95 gastric cancers, 13 high- and 6 low-frequency microsatellite instability cases. The frameshift mutation of Chk1, which resulted in a truncated Chk1 protein, was detected in two high-frequency microsatellite instability cases. Conclusion: These data suggest that the microsatellite instability may contribute to the development of gastric carcinomas through inactivation of Chk1.