跨膜糖蛋白basigin,免疫球蛋白超家族的一员,刺激基质金属蛋白酶(MMP)介导的细胞外基质(ECM)降解,从而驱动癌细胞侵袭。Basigin蛋白水解地从细胞表面脱落,并且血液中高浓度的可溶性Basigin指示癌症患者的不良预后。已经报道了basigin与前列腺癌患者血清中的解整合素和金属蛋白酶(ADAM)-12之间的正相关。然而,这种相关性的功能相关性是未知的。这里,我们显示ADAM12与basigin相互作用并在近膜区域将其裂解。具体来说,ADAM12的过表达增加了碱性磷酸酶标记的basigin报告蛋白从细胞表面的胞外域脱落。此外,CRISPR/Cas9介导的人HeLa癌细胞中ADAM12的敲除导致Basigin报告基因的脱落减少,这可以通过ADAM12的再表达来挽救。我们检测到内源性Basigin片段,对应于ADAM12生成的胞外域的预期大小,在来自表达ADAM12的癌细胞系的条件培养基中,以及一名健康怀孕捐献者和五名膀胱癌患者的血清样本,已知含有高ADAM12水平。支持我们发现的癌症相关性,我们在basigin膜近端区发现了几种癌症相关突变.随后的体外表达表明,这些突变体中的一些更容易发生ADAM12介导的脱落,并且脱落的胞外域可以增强癌细胞的明胶降解。总之,我们将ADAM12鉴定为一种新型Basigin脱落酶,在癌症中具有潜在的意义.
The transmembrane glycoprotein basigin, a member of the immunoglobulin superfamily, stimulates matrix metalloproteinase (MMP)-mediated extracellular matrix (ECM) degradation and thereby drives cancer cell invasion. Basigin is proteolytically shed from the cell surface and high concentrations of soluble basigin in the blood dictates poor prognosis in cancer patients. A positive correlation between basigin and a disintegrin and metalloproteinase (ADAM)-12 in serum from prostate cancer patients has been reported. Yet, the functional relevance of this correlation is unknown. Here, we show that ADAM12 interacts with basigin and cleaves it in the juxtamembrane region. Specifically, overexpression of ADAM12 increases ectodomain shedding of an alkaline phosphatase-tagged basigin reporter protein from the cell surface. Moreover, CRISPR/Cas9-mediated knockout of ADAM12 in human HeLa carcinoma cells results in reduced shedding of the basigin reporter, which can be rescued by ADAM12 re-expression. We detected endogenous basigin fragments, corresponding to the expected size of the ADAM12-generated ectodomain, in conditioned media from ADAM12 expressing cancer cell-lines, as well as serum samples from a healthy pregnant donor and five bladder cancer patients, known to contain high ADAM12 levels. Supporting the cancer relevance of our findings, we identified several cancer-associated mutations in the basigin membrane proximal region. Subsequent in vitro expression showed that some of these mutants are more prone to ADAM12-mediated shedding and that the shed ectodomain can enhance gelatin degradation by cancer cells. In conclusion, we identified ADAM12 as a novel basigin sheddase with a potential implication in cancer.