Kinectin 1 promotes the growth of triple-negative breast cancer via directly co-activating NF-kappaB/p65 and enhancing its transcriptional activity

Lin Gao,Ni Xie,Xiang Gao,Qinhe Yang,Jigang Wang,Wenbin Zhou,Pan Zhao,Junying Qiu,Chang Zou,Hsien-Da Huang,Li Fu,Malin Hong,Shanze Chen,Yong Dai,Bilan Wang,Jinquan Xia

doi:10.1038/s41392-021-00652-x

Abstract

Triple-negative breast cancer (TNBC) is the most challenging subtype of breast cancer. Various endeavor has been made to explore the molecular biology basis of TNBC. Herein, we reported a novel function of factor Kinectin 1 (KTN1) as a carcinogenic promoter in TNBC. KTN1 expression in TNBC was increased compared with adjacent tissues or luminal or Her2 subtypes of breast cancer, and TNBC patients with high KTN1 expression have poor prognosis. In functional studies, knockdown of KTN1 inhibited the proliferation and invasiveness of TNBC both in vitro and in vivo, while overexpression of KTN1 promoted cancer cell proliferation and invasiveness. RNA-seq analysis revealed that the interaction of cytokine-cytokine receptor, particularly CXCL8 gene, was upregulated by KTN1, which was supported by the further experiments. CXCL8 depletion inhibited the tumorigenesis and progression of TNBC. Additionally, rescue experiments validated that KTN1-mediated cell growth acceleration in TNBC was dependent on CXCL8 both in vitro and in vivo. Furthermore, it was found that KTN1 enhanced the phosphorylation of NF-κB/p65 protein at Ser536 site, and specifically bound to NF-κB/p65 protein in the nucleus and cytoplasm of cells. Moreover, the transcription of CXCL8 gene was directly upregulated by the complex of KTN1 and NF-κB/p65 protein. Taken together, our results elucidated a novel mechanism of KTN1 gene in TNBC tumorigenesis and progression. KTN1 may be a potential molecular target for the development of TNBC treatment.

Highlights

Triple-negative breast cancer (TNBC) is a, breast cancer (BCa) subtype with no expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (Her2) protein
The results suggested that NF-κB/p65 protein and NF-κB/p65(Ser536) protein enrichment was increased in Kinectin 1 (KTN1)-overexpressed cells by KTN1, while KTN1 protein and NF-κB/p65(Ser536) protein enrichment was decreased in NF-κB/p65-defiency cells in TNBC cells (Supplementary Fig. S9)
These findings demonstrated that overexpression of KTN1 promoted TNBC tumorigenesis, whereas, knockdown of CXCL8 could neutralize the effect of KTN1 in vivo

Summary

RESULTS

KTN1 is overexpressed in TNBC tumor decreased, while epithelial biomarkers was increased (Fig. 2j). We conducted the luciferase survival rate (Supplementary Fig. S6) These findings suggested that vector containing binding sites of CXCL8, which regulated the overexpression of CXCL8 might be mediated by KTN1 and expression of luciferase reporter gene to detect the activities of contribute to the development of TNBC tumor. Knockdown of KTN1 led to decrease the expression protein is overexpressed in high-grade BCa compared with other of phosphorylated NF-κB/p65 (Ser536) in two cell lines as subtypes of BCa (Supplementary Fig. S2), suggesting that compared to siNC oligo groups (Supplementary Fig. S7a) These upregulation of KTN1 may promote BCa growth and malignancy. IHC analysis of the harvested tumors demonstrated that the expression of mesenchymal biomarkers was markedly decreased, whereas epithelial biomarkers were increased (Fig. 6f) Taken together, these findings demonstrated that overexpression of KTN1 promoted TNBC tumorigenesis, whereas, knockdown of CXCL8 could neutralize the effect of KTN1 in vivo. Data were analyzed using two-tailed Student’s t-test, One-Way ANOVA and Dunnett’s multiple comparison test

DISCUSSION

Findings

MATERIALS AND METHODS