Rack1 mediates tyrosine phosphorylation of Anxa2 by Src and promotes invasion and metastasis in drug-resistant breast cancer cells

Abstract

Background: Acquirement of resistance is always associated with a highly aggressive phenotype of tumor cells. Recent studies have revealed that Annexin A2 (Anxa2) is a key protein that links drug resistance and cancer metastasis. A high level of Anxa2 in cancer tissues is correlated to a highly aggressive phenotype. Increased Anxa2 expression appears to be specific in many drug-resistant cancer cells. The functional activity of Anxa2 is regulated by tyrosine phosphorylation at the Tyr23 site. Nevertheless, the accurate molecular mechanisms underlying the regulation of Anxa2 tyrosine phosphorylation and whether phosphorylation is necessary for the enhanced invasive phenotype of drug-resistant cells remain unknown. Methods: Small interfering RNAs, small molecule inhibitors, overexpression, loss of function or gain of function, rescue experiments, Western blot, wound healing assays, transwell assays, and in vivo metastasis mice models were used to investigate the functional effects of Rack1 and Src on the tyrosine phosphorylation of Anxa2 and the invasion and metastatic potential of drug-resistant breast cancer cells. The interaction among Rack1, Src, and Anxa2 in drug-resistant cells was verified by co-immunoprecipitation assay. Results: We demonstrated that Anxa2 Tyr23 phosphorylation is necessary for multidrug-resistant breast cancer invasion and metastasis. Rack1 is required for the invasive and metastatic potential of drug-resistant breast cancer cells through modulating Anxa2 phosphorylation. We provided evidence that Rack1 acts as a signal hub and mediates the interaction between Src and Anxa2, thereby facilitating Anxa2 phosphorylation by Src kinase. Conclusions: Our findings suggest a convergence point role of Rack1/Src/Anxa2 complex in the crosstalk between drug resistance and cancer aggressiveness. The interaction between Anxa2 and Rack1/Src is responsible for the association between drug resistance and invasive/metastatic potential in breast cancer cells. Thus, our findings provide novel insights on the mechanism underlying the functional linkage between drug resistance and cancer aggressiveness.

Identification of regulatory networks and hub genes controlling mammary gland development and lactation in dairy goats during the late lactation, dry period, and late gestation stages

“…The expression level of RACK1 in the LL stage was the lowest, while it was the highest in the LG stage. The scaffold proteins encoded by RACK1 can participate in the recruitment and assembly of a variety of signaling molecules, including protein kinase C [50], phosphodiesterases [51], Src tyrosine kinase [52], and insulin and insulin-like growth factors [53]. Therefore, RACK1 may participate in the apoptosis of mammary gland cells by regulating a variety of signaling molecules.…”

Metastatic function of METTL18 in breast cancer via actin methylation and Src

“…Src kinase is a well-known oncogenic protein, and a critical role for Src activation in promoting brain metastasis of breast cancer cells has been well-defined (Fan et al, 2019; Lamar et al, 2019). Indeed, blockade of Src gave us a promising activities to suppress metastatic potential of breast tumor cells.…”

Drug-resistant cancer cell-derived exosomal EphA2 promotes breast cancer metastasis via the EphA2-Ephrin A1 reverse signaling

“…Western blotting was performed as described previously [17]. In brief, whole-cell lysates or exosomal proteins were separated by SDS-PAGE and transferred onto PVDF membranes.…”

“…Wound healing assay was performed as described previously [17]. Cells were cultured to con uence in 6well plates and then treated with CM for 12 h. Then, a 10 μL pipette tip was used to scrape a wound on the cell monolayer.…”

“…The width of the wound gap was captured under an inverted microscope. Transwell assay was performed by using a Boyden chamber with a pore size of 8 μm as described previously [17].…”