HSP90 modulates actin dynamics: Inhibition of HSP90 leads to decreased cell motility and impairs invasion

Abstract

HSP90, a major molecular chaperone, plays an essential role in the maintenance of several signaling molecules. Inhibition of HSP90 by inhibitors such as 17-allylamino-demethoxy-geldanamycin (17AAG) is known to induce apoptosis in various cancer cells by decreasing the activation or expression of pro-survival molecules such as protein kinase B (Akt). While we did not observe either decrease in expression or activation of pro-survival signaling molecules in human breast cancer cells upon inhibiting HSP90 with 17AAG, we did observe a decrease in cell motility of transformed cells, and cell motility and invasion of cancer cells. We found a significant decrease in the number of filopodia and lamellipodia, and in the F-actin bundles upon HSP90 inhibition. Our results show no change in the active forms or total levels of FAK and Pax, or in the activation of Rac-1 and Cdc-42; however increased levels of HSP90, HSP90α and HSP70 were observed upon HSP90 inhibition. Co-immuno-precipitation of HSP90 reveals interaction of HSP90 with G-actin, which increases upon HSP90 inhibition. FRET results show a significant decrease in interaction between actin monomers, leading to decreased actin polymerization upon HSP90 inhibition. We observed a decrease in the invasion of human breast cancer cells in the matrigel assay upon HSP90 inhibition. Over-expression of αB-crystallin, known to be involved in actin dynamics, did not abrogate the effect of HSP90 inhibition. Our work provides the molecular mechanism by which HSP90 inhibition delays cell migration and should be useful in developing cancer treatment strategies with known anti-cancer drugs such as cisplatin in combination with HSP90 inhibitors.

HSP90 and HSP70 Proteins Are Essential for Stabilization and Activation of WASF3 Metastasis-promoting Protein

“…When HSP70 was inactivated using shRNA knockdown in cell lines from cervical and bladder cancer, invasion and migration was also suppressed, in the same way these phenotypes are affected by WASF3 knockdown. In other studies of breast cancer (17), treatment with 17-AAG led to decreased filopodia and lamellipodia formation, as well as actin bundles and actin polymerization. These changes were associated with decreased invasion, as we demonstrated for different cell lines in this study.…”

“…HSP90 has emerged as a promising target for the treatment of cancer and inhibition of its function by the 17-AAG drug leads to decreased cancer cell motility and invasion (15)(16)(17). We have recently demonstrated that WASF3 is important in controlling cell motility and invasion in breast and prostate cancer cells (2,3,5).…”

Vibsanin B Preferentially Targets HSP90β, Inhibits Interstitial Leukocyte Migration, and Ameliorates Experimental Autoimmune Encephalomyelitis

“…It dynamically distributes in almost every cellular compartment: the cytoplasmic HSP90, which is the dominant form in the cell and is comprised of a and b isoforms; the endoplasmic reticulum-localized HSP90 protein glucose-regulated protein 94; and the mitochondrial HSP90, which includes the TNF receptorassociated protein (TRAP) family member TRAP1 (14). Recently, it was shown that HSP90 regulates the migration of endothelial cells or tumor cells by influencing cell membrane polarization, which is mainly mediated by the PI3K-AKT pathway (1,(15)(16)(17). Given the similarity between tumor cells and leukocytes with respect to their amoeboid migration (18), HSP90 could also be involved in interstitial leukocyte migration; thus, targeting HSP90 could ameliorate inflammation-associated diseases.…”

Calpain Genetic Disruption and HSP90 Inhibition Combine To Attenuate Mammary Tumorigenesis

“…Although calpain (29,30) and HSP90 (31) have been independently implicated in promoting cell migration and invasion, cooperative effects have not been described. 17AAG alone suppressed MBA-MB-231 cell migration by 20% (P ϭ 4.47 ϫ 10 Ϫ4 ) and 17% (P ϭ 4.44 ϫ 10 Ϫ4 ) at 10 and 25 M, respectively ( Fig.…”

“…Cell migration and metastasis are two essential processes of the metastatic cascade. HSP90 (31) and calpain (29,30) have previously been shown to positively regulate these processes. Inhibition of HSP90 or calpain knockdown was associated with decreased in vitro migration and invasion ( Fig.…”