Profiling follicle stimulating hormone-induced gene expression changes in normal and malignant human ovarian surface epithelial cells.

Epidemiological data have implicated the pituitary gonadotropin follicle stimulating hormone (FSH) as both a risk factor for and a protective agent against epithelial ovarian cancer. Yet, little is known about how this hormone could play such opposing roles in ovarian carcinogenesis. Complementary DNA microarrays containing 2400 named genes were used to examine FSH-induced gene expression changes in ovarian cancer (OC) and immortalized normal human ovarian surface epithelial (HOSE) cell lines. Two-way t-statistics analyses of array data identified two distinct sets of FSH-regulated genes in HOSE and in established OC cell lines established from patients (OVCA cell lines). Among the HOSE cell lines, FSH increased expression of 57% of the 312 genes and downregulated 43%. In contrast, FSH diminished expression of 92% of the 177 genes in the OVCA cell lines. All but 18 of the genes affected by FSH in HOSE cell lines were different from those altered in OVCA cell lines. Among the 18 overlapping genes, nine genes exhibited the same direction of change following FSH challenge, while the other nine showed discordance in response between HOSE and OVCA cell lines. The FSH-induced differential expression of seven out of nine genes was confirmed by real-time RT-PCR. Gene-specific antisense oligonuleotides (ODNs) were used to inhibit the expression of genes encoding GTPase activating protein (rap1GAP), neogenin, and restin in HOSE and OVCA cells. Antisense ODNs to neogenin and restin, but not an antisense ODN to rap1GAP, were effective in inhibiting OVCA cell growth, diminishing proliferating cell nuclear antigen expression, and increasing caspase 3 activities. Furthermore, the ODN to rap1GAP was further shown to be ineffective in altering migration properties of OVCA cell lines. HOSE cell proliferation was not affected by treatment with any of the antisense ODNs. In summary, gene profiling data reveal for the first time that FSH may exert different biological actions on OVCA cells than on HOSE cells, by differential regulation of a set of putative oncogenes/tumor suppressors. Specifically, neogenin and restin were found to exhibit proproliferation/survival action on OC cells.

Molecular mechanisms underlying SHP-1 gene expression.

SHP-1, a protein-tyrosine phosphatase with two src-homology 2 domains, is expressed predominantly in hematopoietic and epithelial cells and has been implicated in numerous signaling pathways as a negative regulator. Two promoters direct the expression of human and murine SHP-1, and two types of transcripts (I) and (II) SHP-1, are initiated from each of these promoters. The cDNA sequences of (I)SHP-1 and (II)SHP-1 are identical except in the 5' untranslated region and in the first few coding nucleotides. In this report, we show that promoter usage is similar in mouse and human hematopoietic cells, but different in epithelial cells. In human epithelial cells, only (I)SHP-1 transcripts were expressed. In addition, 4beta-phorbol 12-myristate 13-acetate up-regulates human (I)SHP-1 transcript expression in SKOV3 cells (an ovarian cancer cell line). Indirect evidence suggests that nuclear factor-kappaB might play a role in this induction. We also show that a 12-bp repeat in the distal SHP-1 promoter, which directs (I)SHP-1 expression, is of functional relevance as deletion of one copy of this E-box-containing 12-bp repeat resulted in a significant decrease in promoter activity. Electrophoretic mobility shift assays and supershift experiments showed that the upstream stimulatory factors USF1 and USF2 hetero-dimerize and interact with this 12 bp repeat. Our results suggest that USFs which have antiproliferative functions might regulate the expression of SHP-1, which itself is predominantly a negative growth regulator.