CBP501 inhibits EGF-dependent cell migration, invasion and epithelial-to-mesenchymal transition of non-small cell lung cancer cells by blocking KRas to calmodulin binding

Abstract

The anti-cancer agent CBP501 binds to calmodulin (CaM). Recent studies showed that migration and metastasis are inhibited by several CaM antagonists. However, there is no available evidence that CBP501 has similar effects. Here we found that CBP501 inhibits migration of non-small cell lung cancer (NSCLC) cells in vitro, even in the presence of migration inducing factors such as WNT, IL-6, and several growth factors. CBP501 also inhibited epidermal growth factor (EGF) enhanced invasion and the epithelial-to-mesenchymal transition (EMT), and this inhibition was accompanied by (i) suppression of Akt and ERK1/2 phosphorylation, and (ii) suppression of expression of transcription factor Zeb1 and the mesenchymal marker Vimentin. A pull down analysis performed using sepharose-immobilized CaM showed that CBP501 blocks the interaction between CaM and KRas. Furthermore, EGF induced Akt activation and cell migration was effectively suppressed by KRas down-regulation in NSCLC cells. Stable knockdown of KRas also made cells insensitive to CBP501’s inhibition of growth factor-induced migration. Taken together, these results indicate that CBP501 inhibits binding of CaM with KRas and thereby suppresses the PI3K/AKT pathway, migration, invasion and EMT. These findings have identified a previously unrecognized effect of CBP501 on downstream KRas signaling mechanisms involving EMT and invasion, and provide support for the further clinical development of this agent.

Silencing of RAD51AP1 suppresses epithelial–mesenchymal transition and metastasis in non‐small cell lung cancer

“…Vimentin and E‐cadherin play key roles in EMT, for instance, downregulation of E‐cadherin subsequently leads to deprived epithelial morphology and an acquired aggressive mesenchymal phenotype . Existing literature supports the involvement of upregulated vimentin in cell migration and tissue invasion, as well as poor survival in resected NSCLC patients . Evidence has been presented of the regulation of various epithelial markers (E‐cadherin, occludin, and CK18) and mesenchymal markers (such as N‐cadherin) by MUC4, which promotes invasion and metastasis in pancreatic cancer .…”

Transfer of Extracellular Vesicle-Associated-RNAs Induces Drug Resistance in ALK-Translocated Lung Adenocarcinoma

“…To determine the functional effects of EV transfer, cell viability and motility were determined by MTT cell viability assay and cell migration assay respectively. Cell migration was performed using the transwell migration assay in EV recipient cells [43]. Briefly, ALK-TKI-sensitive subclones FA34.8 were treated with EVs (10 μg/mL isolated from CM of drug resistant subclones for 24 h. Treated cells were then subjected to transwell migration assay with corresponding EV loaded into the lower chamber.…”

The Role of Calmodulin in Tumor Cell Migration, Invasiveness, and Metastasis

“…The results obtained in this murine model, however, do not necessarily lead to useful insights into the biology of human cancers. In any event, the CaM antagonist CBP501, a modified-peptide, inhibited human NSCLC cell migration, EGF-induced invasiveness, and EMT by blocking the interaction between CaM with K-Ras, as well as metastasis formation by Lewis lung carcinoma cells, leading to inhibition of cytokine production by the tumor-associated macrophages [71,72]. W-7 also downregulates the metastatic-associated suppressor genes MTS1 (multiple tumor suppressor 1) and NM23 in mouse melanoma [86].…”