TY - JOUR
T1 - Loss of HSulf-1 expression enhances tumorigenicity by inhibiting Bim expression in ovarian cancer
AU - He, Xiaoping
AU - Khurana, Ashwani
AU - Roy, Debarshi
AU - Kaufmann, Scott
AU - Shridhar, Viji
PY - 2014/10/15
Y1 - 2014/10/15
N2 - The expression of human Sulfatase1 (HSulf-1) is downregulated in the majority of primary ovarian cancer tumors, but the functional consequence of this downregulation remains unclear. Using two different shRNAs (Sh1 and Sh2), HSulf-1 expression was stably downregulated in ovarian cancer OV202 cells. We found that HSulf-1-deficient OV202 Sh1 and Sh2 cells formed colonies in soft agar. In contrast, nontargeting control (NTC) shRNA-transduced OV202 cells did not form any colonies. Moreover, subcutaneous injection of OV202 HSulf-1-deficient cells resulted in tumor formation in nude mice, whereas OV202 NTC cells did not. Also, ectopic expression of HSulf-1 in ovarian cancer SKOV3 cells significantly suppressed tumor growth in nude mice. Here, we show that HSulf-1-deficient OV202 cells have markedly decreased expression of proapoptotic Bim protein, which can be rescued by restoring HSulf-1 expression in OV202 Sh1 cells. Enhanced expression of HSulf-1 in HSulf-1-deficient SKOV3 cells resulted in increased Bim expression. Decreased Bim levels after loss of HSulf-1 were due to increased p-ERK, because inhibition of ERK activity with PD98059 resulted in increased Bim expression. However, treatment with a PI3 kinase/AKT inhibitor, LY294002, failed to show any change in Bim protein level. Importantly, rescuing Bim expression in HSulf-1 knockdown cells significantly retarded tumor growth in nude mice. Collectively, these results suggest that loss of HSulf-1 expression promotes tumorigenicity in ovarian cancer through regulating Bim expression.
AB - The expression of human Sulfatase1 (HSulf-1) is downregulated in the majority of primary ovarian cancer tumors, but the functional consequence of this downregulation remains unclear. Using two different shRNAs (Sh1 and Sh2), HSulf-1 expression was stably downregulated in ovarian cancer OV202 cells. We found that HSulf-1-deficient OV202 Sh1 and Sh2 cells formed colonies in soft agar. In contrast, nontargeting control (NTC) shRNA-transduced OV202 cells did not form any colonies. Moreover, subcutaneous injection of OV202 HSulf-1-deficient cells resulted in tumor formation in nude mice, whereas OV202 NTC cells did not. Also, ectopic expression of HSulf-1 in ovarian cancer SKOV3 cells significantly suppressed tumor growth in nude mice. Here, we show that HSulf-1-deficient OV202 cells have markedly decreased expression of proapoptotic Bim protein, which can be rescued by restoring HSulf-1 expression in OV202 Sh1 cells. Enhanced expression of HSulf-1 in HSulf-1-deficient SKOV3 cells resulted in increased Bim expression. Decreased Bim levels after loss of HSulf-1 were due to increased p-ERK, because inhibition of ERK activity with PD98059 resulted in increased Bim expression. However, treatment with a PI3 kinase/AKT inhibitor, LY294002, failed to show any change in Bim protein level. Importantly, rescuing Bim expression in HSulf-1 knockdown cells significantly retarded tumor growth in nude mice. Collectively, these results suggest that loss of HSulf-1 expression promotes tumorigenicity in ovarian cancer through regulating Bim expression.
KW - Bim
KW - HSulf-1
KW - ovarian cancer
KW - tumorigenicity
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U2 - 10.1002/ijc.28818
DO - 10.1002/ijc.28818
M3 - Article
C2 - 24596063
AN - SCOPUS:84905735682
SN - 0020-7136
VL - 135
SP - 1783
EP - 1789
JO - International Journal of Cancer
JF - International Journal of Cancer
IS - 8
ER -