Involvement of adaptor protein Crk in malignant feature of human ovarian cancer cell line MCAS

Abstract

Signaling adaptor protein Crk regulates cell motility and growth through its targets Dock180 and C3G, those are the guanine-nucleotide exchange factors (GEFs) for small GTPases Rac and Rap, respectively. Recently, overexpression of Crk has been reported in various human cancers. To define the role for Crk in human cancer cells, Crk expression was targeted in the human ovarian cancer cell line MCAS through RNA interference, resulting in the establishment of three Crk knockdown cell lines. These cell lines exhibited disorganized actin fibers, reduced number of focal adhesions, and abolishment of lamellipodia formation. Decreased Rac activity was demonstrated by pull-down assay and FRET-based timelapse microscopy, in association with suppression of both motility and invasion by phagokinetic track assay and transwell assay in these cells. Furthermore, Crk knockdown cells exhibited slow growth rates in culture and suppressed anchorage-dependent growth in soft agar. Tumor forming potential in nude mice was attenuated, and intraperitoneal dissemination was not observed when Crk knockdown cells were injected into the peritoneal cavity. These results suggest that the Crk is a key component of focal adhesion and involved in cell growth, invasion, and dissemination of human ovarian cancer cell line MCAS.

CRKL plays a pivotal role in tumorigenesis of head and neck squamous cell carcinoma through the regulation of cell adhesion

“…2A). Since CRK was already known to contribute to cell adhesion and motility [10][11][12], we investigated whether CRKL has similar biological mechanisms.…”

“…The bound cells in each well were lysed, stained with 0.04% crystal violet, and quantified by spectrophotometry at OD 595 nm [10].…”

“…CRK was shown to play an essential role in the malignant potential of various human tumors including ovarian cancer, synovial sarcoma, glioblastoma, and head and neck squamous cell carcinoma (HNSCC) [10][11][12][13].…”

Fibroblast Growth Requires CT10 Regulator of Kinase (Crk) and Crk-like (CrkL)

“…Overexpression of Crk and CrkL has been reported in several human cancers, including oral squamous cell carcinoma (5), ovarian carcinoma (6), colon cancer (7), lung cancer (8,9), breast cancer (10,11), gastric cancer (12), and glioblastoma (13,14). Reduced expression of either Crk or CrkL by RNA interference-mediated knockdown lowered the in vivo tumor formation of human ovarian (15), synovial sarcoma (16), glioblastoma (14), breast cancer (10), head and neck squamous cell carcinoma (17), and rhabdomyosarcoma (18) cell lines. Taken together, these reports imply that elevated levels of Crk family proteins promote cell transformation and enhance tumor cell growth (for review see Refs.…”

PTPN4 negatively regulates CrkI in human cell lines

“…In this way, CrkI functions as a signaling adaptor protein to mediate diverse cellular responses, including proliferation, differentiation and migration [25][26][27]. Overexpression of CrkI has been detected in many types of human cancer cells [16,[28][29][30][31]. A possible role has been suggested for CrkI during these tumorigenesis events, specifically in mediating intracellular signaling related to cell motility and proliferation [29].…”