ARHI overexpression induces epithelial ovarian cancer cell apoptosis and excessive autophagy.
OBJECTIVE
ARHI is a maternally imprinted tumor suppressor gene that is responsible for initiating programmed cell death and inhibiting cancer cell growth. However, the influence of ARHI on epithelial ovarian cancer cell death and the underlying mechanisms behind how ARHI regulates cancer cells still require further studies.


METHODS
Epithelial ovarian cancer cells TOV112D and ES-2 were used in this in vitro study. Cell proliferation, apoptosis, and autophagy activities were compared in TOV112D and ES-2 cells transfected with ARHI vectors or control vectors. Bcl-2 siRNA was transfected into TOV112D cells to investigate the roles of Bcl-2 played in regulating apoptosis and autophagy.


RESULTS
ARHI expression was reduced in TOV112D and ES-2 cells compared with normal epithelial ovarian cells (NOE095 and HOSEpiC). Overexpressed ARHI inhibited cancer cell proliferation, whereas induced forced cell apoptosis and excessive formation of autophagosomes inhibited promoted cell death. Furthermore, we found that Bcl-2 expression moderately declined in response to ARHI overexpressing in ES-2 and TOV112D cells; meanwhile, more apoptotic cells and higher LC3 level presented after silence of Bcl-2 in TOV112D cells. Reduced Bcl-2-Beclin 1 complex were observed in ARHI overexpressing cells. Moreover, modulation of ARHI to Bcl-2 expression could be ascribed partially to the activation of PI3k/AKT pathway. The addition of LY294002 enabled to suppress Bcl-2 expression and cell proliferation.


CONCLUSIONS
The silence of ARHI expression in vitro seems to accelerate the malignant transformation of healthy ovarian cells by restraining apoptosis and autophagy. The overexpressed ARHI in TOV112D cancer cells suppresses the activation of PI3K/AKT and reduces the expression of Bcl-2, leading to enhanced cell apoptosis and autophagic cancer cell death.
Departments of *Gynecology and Obstetrics, †Orthopedics, and ‡Pathology, General Hospital of PLA, Beijing, People's Republic of China.
Jie
J
Li
Geng
G
Cui
Lu
L
Sun
Shu-Juan
SJ
Wang
Shuang
S
Tian
Zheng
Z
Guan
Wen-Sheng
WS
Fan
Zhi-Feng
ZF
Yan
Yi-Zhuo
YZ
Yang
Yan-Qin
YQ
You
Xiao-Yu
XY
Fu
Li-An
LA
Li
Ke
K
Huang
Ya-Li
YL
Li
Yuan-Guang
YG
Meng
D000230:Adenocarcinoma / Q000378:metabolism*; D017209:Apoptosis; D001343:Autophagy; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D015536:Down-Regulation; D005260:Female; D006801:Humans; D010051:Ovarian Neoplasms / Q000378:metabolism*; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000378:metabolism*
C117386:DIRAS3 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D058539:Phosphatidylinositol 3-Kinase; D051057:Proto-Oncogene Proteins c-akt; D020741:rho GTP-Binding Proteins