TY - JOUR
T1 - Expression of chromobox homolog 7 (CBX7) is associated with poor prognosis in ovarian clear cell adenocarcinoma via TRAIL-induced apoptotic pathway regulation
AU - Shinjo, Kanako
AU - Yamashita, Yoriko
AU - Yamamoto, Eiko
AU - Akatsuka, Shinya
AU - Uno, Nozomi
AU - Kamiya, Akihiro
AU - Niimi, Kaoru
AU - Sakaguchi, Yuka
AU - Nagasaka, Tetsuro
AU - Takahashi, Takashi
AU - Shibata, Kiyosumi
AU - Kajiyama, Hiroaki
AU - Kikkawa, Fumitaka
AU - Toyokuni, Shinya
PY - 2014/7/15
Y1 - 2014/7/15
N2 - Ovarian cancer is the most lethal gynecologic malignancy, and clear cell adenocarcinoma of the ovary (OCCA), in particular, has a relatively poor prognosis among the ovarian cancer subtypes because of its high chemoresistance. Chromobox (CBX) 7 is a polycomb repressive complex 1 component that prolongs the lifespan of normal human cells by downregulating the INK4a/ARF expression which promotes cell-cycle progression. However, recent reports studying the relationship between CBX7 expression and patient survival have differed regarding the tumor cell origins, and the precise role of CBX7 in human carcinomas remains obscure. In this study, we analyzed CBX7 expression by immunohistochemistry in 81 OCCA patients and evaluated its association with their clinical outcomes. Both the overall and progression-free survival rates of the CBX7-positive patients were significantly shorter than those of the CBX7-negative patients (p < 0.05). CBX7 knockdown experiments using two OCCA cell lines, TOV21G and KOC-7C, revealed that cell viability was significantly reduced compared to the control cells (p < 0.001). Expression microarray analysis revealed that apoptosis-related genes, particularly tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), were significantly upregulated in CBX7 knockdown cells (p < 0.01). We further confirmed that CBX7 knockdown resulted in TRAIL-induced apoptosis in the OCCA cells. Thus, in this study, we showed for the first time that CBX7 was associated with a decreased OCCA prognosis. We also successfully demonstrated that the TRAIL pathway is a novel target for CBX7 expression modulation in these cells, and therapeutic agents utilizing the TRAIL pathway may be particularly effective for targeted OCCA therapy. What's new? Ovarian cancer is the most lethal gynecologic malignancy, with clear celladenocarcinoma of the ovary (OCCA) having a particularly poor prognosis due to high chemoresistance. Chromobox homolog 7 (CBX7) is a polycomb group transcriptional repressor whose role in human cancer remains controversial. Here, the authors showed for the first time that CBX7 expression is related to worse prognosis in OCCA. Furthermore, knockdown of CBX7 in vitro induced apoptosis in OCCA cell lines, possibly via regulation of the TRAIL-pathway. The findings thus indicate CBX7 as a good prognostic marker, andthe TRAIL-pathway as a potential target for OCCA diagnosis and therapy.
AB - Ovarian cancer is the most lethal gynecologic malignancy, and clear cell adenocarcinoma of the ovary (OCCA), in particular, has a relatively poor prognosis among the ovarian cancer subtypes because of its high chemoresistance. Chromobox (CBX) 7 is a polycomb repressive complex 1 component that prolongs the lifespan of normal human cells by downregulating the INK4a/ARF expression which promotes cell-cycle progression. However, recent reports studying the relationship between CBX7 expression and patient survival have differed regarding the tumor cell origins, and the precise role of CBX7 in human carcinomas remains obscure. In this study, we analyzed CBX7 expression by immunohistochemistry in 81 OCCA patients and evaluated its association with their clinical outcomes. Both the overall and progression-free survival rates of the CBX7-positive patients were significantly shorter than those of the CBX7-negative patients (p < 0.05). CBX7 knockdown experiments using two OCCA cell lines, TOV21G and KOC-7C, revealed that cell viability was significantly reduced compared to the control cells (p < 0.001). Expression microarray analysis revealed that apoptosis-related genes, particularly tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), were significantly upregulated in CBX7 knockdown cells (p < 0.01). We further confirmed that CBX7 knockdown resulted in TRAIL-induced apoptosis in the OCCA cells. Thus, in this study, we showed for the first time that CBX7 was associated with a decreased OCCA prognosis. We also successfully demonstrated that the TRAIL pathway is a novel target for CBX7 expression modulation in these cells, and therapeutic agents utilizing the TRAIL pathway may be particularly effective for targeted OCCA therapy. What's new? Ovarian cancer is the most lethal gynecologic malignancy, with clear celladenocarcinoma of the ovary (OCCA) having a particularly poor prognosis due to high chemoresistance. Chromobox homolog 7 (CBX7) is a polycomb group transcriptional repressor whose role in human cancer remains controversial. Here, the authors showed for the first time that CBX7 expression is related to worse prognosis in OCCA. Furthermore, knockdown of CBX7 in vitro induced apoptosis in OCCA cell lines, possibly via regulation of the TRAIL-pathway. The findings thus indicate CBX7 as a good prognostic marker, andthe TRAIL-pathway as a potential target for OCCA diagnosis and therapy.
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U2 - 10.1002/ijc.28692
DO - 10.1002/ijc.28692
M3 - Article
C2 - 24375438
AN - SCOPUS:84899998613
SN - 0020-7136
VL - 135
SP - 308
EP - 318
JO - International Journal of Cancer
JF - International Journal of Cancer
IS - 2
ER -