Overexpression of CARMA3 in Non-Small-Cell Lung Cancer Is Linked for Tumor Progression

Zixuan Li,Lifeng Liu,Enhua Wang,Wenting Luo,Xueshan Qiu,Lianyue Qu,Bo Huang,Ying Xu,Zhongping Tang,Haiying Li,Qianze Dong,William C S Cho

doi:10.1371/journal.pone.0036903

Zixuan Li, Lifeng Liu + Show 10 more

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https://doi.org/10.1371/journal.pone.0036903

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Abstract

We aimed to investigate the clinical significance of the expression of novel scaffold protein CARMA3 in non-small-cell lung cancer (NSCLC) and the biological function of CARMA3 in NSCLC cell lines. We observed moderate to high CARMA3 staining in 68.8% of 141 NSCLC specimens compared to corresponding normal tissues. The overexpression of CARMA3 was significantly correlated with TNM stage (P = 0.022) and tumor status (P = 0.013). CARMA3 upregulation also correlated with a shorter survival rate of patients of nodal status N0 (P = 0.042)as well as the expression of epidermal growth factor receptor (EGFR) (P = 0.009). In EGFR mutation positive cases, CARMA3 expression was much higher (87.5%) compared to non-mutation cases (66.1%). In addition, we observed that knockdown of CARMA3 inhibits tumor cell proliferation and invasion, and induces cell cycle arrest at the boundary between the G1 and S phase. We further demonstrated a direct link between CARMA3 and NF-κB activation. The change of biological behavior in CARMA3 knockdown cells may be NF-κB-related. Our findings demonstrated, for the first time, that CARMA3 was overexpressed in NSCLC and correlated with lung cancer progression, EGFR expression, and EGFR mutation. CARMA3 could serve as a potential companion drug target, along with NF-kB and EGFR in EGFR-mutant lung cancers.

Highlights

CARMA3 belongs to the CARMA family and contains three members, CARMA1, CARMA2 (CARD14), and CARMA3
We use western-blotting to analyze the expression of CARMA3 in 18 cases.The results show that 56% of the lung cancer specimens show moderate to high CARMA3 expression (Figure S2, S3)
Our results demonstrated that CARMA3 protein expression in lung cancer tissues is higher compared to corresponding normal lung tissues

Summary

Introduction

CARMA3 ( known as CARD10 or Bimp1) belongs to the CARMA family and contains three members, CARMA1 ( known as CARD11), CARMA2 (CARD14), and CARMA3 These three proteins share similar structural motifs, contain a CARD domain, a Src-homology 3 (SH3) domain, one or several PDZ domains, and a GuK domain. Recent studies have demonstrated that CARMA3, as a scaffold protein, plays a critical role in GPCR ligands and PKC-induced NF-kB activation [5,6,7,8]. The PKCa-CARMA3 signaling axis plays an essential role in LPA-induced ovarian cancer cell in vitro invasion [17]. A recent study demonstrated that CARMA3 deficiency impaired cancer cell proliferation in vitro and in vivo, and inhibited survival, migration, and invasion in human breast cancer cell lines MDA468 and A431 [18]. We assessed the association of CARMA3 expression with the proliferation and metastatic potential of several NSCLC cell lines

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