Objective: Overexpression of progranulin (also named acrogranin, PC-cell-derived growth factor, or granulin-epithelin precursor) is associated with ovarian cancer, specifically with cell proliferation, malignancy, chemoresistance, and shortened overall survival. The objective of the current study is to identify the signaling pathways involved in the regulation of progranulin expression in ovarian cancer cell lines.
Methods: We studied the relation of protein kinase C (PKC), phosphatidylinositol 3-kinase, protein kinase A, P38, extracellular signal-regulated kinase, and Akt pathways on the modulation of progranulin expression levels in NIH-OVCAR-3 and SK-OV-3 ovarian cancer cell lines. The different pathways were examined using pharmacological inhibitors (calphostin C, LY294002, H89, SB203580, PD98059, and Akt Inhibitor), and mRNA and protein progranulin expression were analyzed by reverse transcriptase polymerase chain reaction and Western blot techniques, respectively.
Results: Inhibition of PKC signal transduction pathway by calphostin C decreased in a dose-dependent manner protein but not mRNA levels of progranulin in both ovarian cancer cell lines. LY294002 but not wortmannin, which are phosphatidylinositol 3-kinase inhibitors, also diminished the expression of progranulin in both cell lines. In addition, LY294002 treatment produced a significant reduction in cell viability. Inhibition of protein kinase A, P38, extracellular signal-regulated kinase, and Akt did not affect progranulin protein expression.
Conclusions: These results suggest that the PKC signaling is involved in the regulation of progranulin protein expression in 2 different ovarian cancer cell lines. Inhibiting these intracellular signal transduction pathways may provide a future therapeutic target for hindering the cellular proliferation and invasion in ovarian cancer produced by progranulin.
*Research Unit in Reproductive Medicine, Unidad Medica de Alta Especialidad en Ginecologia y Obstetricia “Luis Castelazo Ayala,” Instituto Mexicano del Seguro Social; and †Department of Biochemistry, School of Medicine, Universidad Nacional Autonoma de Mexico, México DF, Mexico.
Address correspondence and reprint requests to Laura Diaz-Cueto, MD, PhD, Research Unit in Reproductive Medicine, IMSS, Rio Magdalena 289, Sexto Piso, Tizapan San Angel, CP 01090, México DF, Mexico. E-mail: email@example.com.
This work was supported by grants from the Fondo de Investigación en Salud, Instituto Mexicano del Seguro Social (FIS/IMSS/PROT/C2007/016 and FIS/IMSS/PROT/C2007/518) to Dr Laura Diaz-Cueto. Adriana Diaz-Arizaga was a graduate student from the Universidad Nacional Autonoma de Mexico and was supported by scholarships from the CONACYT and the Instituto Mexicano del Seguro Social, Mexico.
The authors declare that there are no conflicts of interest.
Received February 4, 2012
Accepted February 29, 2012