Differential activation of protein kinase C in the osmosensing signaling pathways of human cervical cells with different tumor potential

Previous studies show that the regulatory volume decrease (RVD) in human cervical cells with different tumor potential is mediated by different ion channels. The signaling events involved in regulating these channel activities are not clear. To screen the possible mechanisms involved in cell volume regulation in these cells, we examine intracellular mechanisms and second messengers listed as follows: phospholipase C, phospholipase A₂, tyrosine kinase, protein kinase C, protein kinase A, and cAMP. Our results showed the differential activation of protein kinase C in different human cervical epithelial cell types. Phospholipase C signaling with downstream activation of protein kinase C was involved during the process of RVD in cervical cancer cells. On the other hand, protein kinase C isoform that is not related to upstream phospholipase C regulation was involved in the RVD of human papillomavirus-immortalized and normal cervical epithelia.