Protein kinase C isoforms involved in regulation of cell shape and locomotion of human fibrosarcoma HT1080 cells

Abstract

The role of protein kinase C (PKC) isoforms in the regulation of cell shape [switch between fibroblast‐like and crescent shape (CS)] and of locomotion of human fibrosarcoma HT1080 cells has been investigated. The PKC activator phorbol myristate acetate (PMA) induced the transition of elongated fibroblast‐like cells into CS cells and stimulated locomotion. Both responses to PMA were inhibited by the PKC inhibitor Ro 31‐8220. Analysis of the time course showed that stimulation of shape changes (formation of CS cells) and locomotor activity (increase in the proportion and speed of locomoting cells) was maximal in the early phase of the response (up to 2.5 hr) and significantly decreased later (15 to 21 hr). CS formation and stimulated locomotion correlated closely with a marked redistribution from the cytosol to the membrane of PKC isoforms α, β1 and γ in the early phase (0.5 to 2 hr) following activation with PMA. The subsequent reduction of the proportion of CS cells and of cell locomotion correlated with down‐regulation of these isoforms in the second phase (16 to 21 hr). In contrast, the total amount and distribution of PKC β2 remained almost unchanged with 10–8 M PMA up to 21 hr. Furthermore, changes in shape and locomotion did not correlate with the responses of PKC δ to PMA. Inhibition of PMA‐stimulated locomotion by the more specific inhibitor Gö 6976 is consistent with a role of PKC α and β1 in this response. Ro 31‐8220 alone induced a moderate down‐regulation of PKC isoforms α and δ, but it also inhibited the more pronounced down‐regulation of these isoforms by PMA. Our results indicate that activation of PKC isoforms α, γ and β1, but not β2 or δ, stimulates locomotion and formation of CS cells in human fibrosarcoma HT1080 cells. Int. J. Cancer 88:195–203, 2000. © 2000 Wiley‐Liss, Inc.

Differential regulation of keratinocyte chemokinesis and chemotaxis through distinct nicotinic receptor subtypes

“…PKC-δ has been reported to play a major role in initiating and sustaining cell migration (Andre et al, 1999;Keller et al, 2000;Kruger and Reddy, 2003;Li et al, 1980), and in tumorcell metastasis (Kiley et al, 1999). The signaling pathway involving both PKC-δ and RhoA has been implicated in mediating regulation of cell motility downstream of other types of cell surface receptors, such as the leukotriene D 4 , lysophosphatidic acid and bombesin receptors (Barry and Critchley, 1994;Massoumi et al, 2002).…”

PKC signalling regulates tight junction membrane assembly in the pre-implantation mouse embryo

“…The inhibitor was washed out before activator treatment to avoid interaction between the two chemicals. These protein kinase inhibitors inhibit PKC at nanomolar concentrations (100-1000-fold more efficient for PKC than, for example, for PKA) and can be effective within minutes of treatment within other systems (Staendart et al 1997, Lin & Chen 1998, Keller et al 2000. The inhibitors have been shown to affect a broad range of PKC isoforms with slightly varying efficiency (summarised in Way et al 2000).…”

Protein kinase Cδ in tumorigenesis of human malignant fibrous histiocytoma

“…Several PKC isoforms have been reported to act as regulators of cell differentiation, growth, survival, migration, invasion, and apoptosis in various human malignancies (7,10,(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33). Therefore, PKC may be an attractive candidate for targeting using novel anticancer therapies.…”

“…Therefore, PKC may be an attractive candidate for targeting using novel anticancer therapies. Among the PKC isoforms, PKCα, β, and γ are the most abundant isoforms in various tissues (19), and in general, PKCα and PKCβ have been linked to increased invasion, proliferation, drug resistance and genetic instability in tumor cells (9,19,21,(24)(25)(26)(27)(28)(29)(30)(31)(32), while PKCδ is thought to promote apoptosis (7,10,33). Koivunen et al theorized that increased proportional activation of PKCα/β to PKCδ is an important factor in the aggressiveness of cancers (9), and other studies demonstrated that PKCβ plays an important role in the signal transduction pathway for vascular endothelial growth factor-mediated tumor development and angiogenesis in human malignancies (26,27).…”

“…Keller et al reported that the PKC isoforms α, γ and β1, but not β2 or δ, are involved in the regulation of cell shape and locomotion of human fibrosarcoma HT1080 cells (30). Zhan et al demonstrated that p53 signaling has been linked to the regulation of PKCα expression, and that PKCα activates the multiple drug resistance (MDR) gene in a human leiomyosarcoma cell line (31).…”