Filip1l, or Filamin A-interacting protein 1-like, is a multifunctional protein involved in various biological processes [4]. It has been associated with cancer progression, apoptosis, and angiogenesis. It may also have a connection with mitochondria as it colocalizes with the mitochondrial marker TOM20 [4]. In cancer, its down-regulation through promoter hypermethylation has been observed in multiple types, and when overexpressed, it inhibits cancer cell invasion and metastasis via inhibiting canonical WNT signaling [5].

In mucinous colorectal adenocarcinoma, loss of Filip1l increased xenograft growth, and in colon-specific knockout mice, it induced colonic epithelial hyperplasia and mucin secretion. It was found that Filip1l is required for proper centrosomal localization of PFDN1 and regulates its proteasome-dependent degradation. Down-regulation of Filip1l led to increased PFDN1, driving multinucleation and cytokinesis defects [1]. In lung adenocarcinoma, cigarette smoking caused Filip1l down-regulation by promoter methylation. Lung-specific knockout mice with loss of Filip1l showed increased xenograft growth, lung adenoma formation, and mucin secretion [2]. In posterior capsular opacification, knockdown of Filip1l enhanced epithelial-mesenchymal transition (EMT), extracellular matrix (ECM) synthesis, and cell migration, while its overexpression reversed these effects [3].

In conclusion, Filip1l plays essential roles in processes like apoptosis, cell division, and cell-matrix interactions. Gene knockout mouse models, such as in colon-specific and lung-specific knockout mice, have revealed its significance in cancer development and other pathological conditions like posterior capsular opacification. These findings suggest Filip1l could be a potential therapeutic target in related diseases.