Filippi syndrome: Three new families suggest that urinary system abnormalities may belong to clinical spectrum of the disease.

Filippi syndrome is a rare genetic disorder characterized by growth and neurodevelopmental delays, dysmorphism, and selective limb abnormalities. Although the syndrome was described approximately four decades ago, only a few families with molecularly confirmed diagnoses have been reported. In this article, we present three new patients of Filippi syndrome with unusual clinical and genetic aspects. These patients exhibited novel clinical features that have not previously been associated with Filippi syndrome, including renal hypoplasia/aplasia, renal cysts, renal cortical thinning, hypomelanotic, and hypermelanotic macules. All three patients had homozygous frameshift variants of the CKAP2L gene, specifically NM_152515.3: c.554_555del, c.981_982del, and c.1463_1467del, with the second being a novel variant. Given the limited number of reported Filippi syndrome patients to date and the ongoing discovery of new clinical aspects of the disease, exploring its potential connection with kidney and skin pigmentation abnormalities could be valuable for future research.

IGF2BP2 promotes ovarian cancer growth and metastasis by upregulating CKAP2L protein expression in an m6 A-dependent manner.

Ovarian cancer (OC) is the second leading cause of gynecological cancer-related death in women worldwide. N6-methyladenosine (m6 A) is the most abundant internal modification in eukaryotic RNA. Human insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2), an m6 A reader, can enhance mRNA stability and promote translation by recognizing m6 A modifications. Its tumor-promoting effects have been demonstrated in several cancers. However, the roles of m6 A modification and IGF2BP2 in OC remain unclear. Here, by using methylated RNA immunoprecipitation sequencing, we demonstrated that there is widespread dysregulation of m6 A modification in OC tissues. The m6 A modification and the mRNA and protein levels of IGF2BP2 were significantly elevated in OC. Overexpression of IGF2BP2 facilitated OC cell proliferation, migration, and invasion in vitro and accelerated tumor growth and metastasis in vivo. While IGF2BP2-knockdown showed the opposite effect. Mechanistically, we identified cytoskeleton-associated protein 2-like (CKAP2L) as a target of IGF2BP2. IGF2BP2 promoted CKAP2L translation dependent on m6 A modification, rather than affecting mRNA and protein stability. Overexpression of CKAP2L rescued the tumor-suppressive effect of IGF2BP2 knockdown in OC cells. In conclusion, this study revealed the potential role of IGF2BP2 in tumor progression, at least partially via promoting the translation of CKAP2L in an m6 A-dependent manner.

CKAP2L, a crucial target of miR-326, promotes prostate cancer progression.

BACKGROUND: The overexpression of aberrant cell cycle signaling pathway associated protein has been implicated in multiple malignancies and the identification of all-important one among is the crux of the precise targeted therapy. CKAP2L (Cytoskeleton Associated Protein 2 Like) plays a newish role in cancer progression through activation of the process of cell cycle and mitosis. In this study, we aim to delineate the prominent dysregulated expression of CKAP2L and comprehensively reveal its deregulation in prostate cancer.  METHOD: CKAP2L expression was examined in the normal and tumor tissues of prostate cancer patients with RT-QPCR and Western blot. IHC showed the different expression in normal prostate tissue, tissue of BPH, low Gleason Score and high Gleason Score prostate cancer patients. Transwell, colony formation, MTT and flow cytometry were performed to detected the changes in cellular function in vitro. The xenograft model was conducted for the changes in vivo. Dual luciferase and RIP proved the binding relation between CKAP2L and miR-326. RESULTS: In multiple datasets, CKAP2L was found upregulated and positively associated with Gleason grade and poor clinical outcomes of patients. shRNA mediated silence of CKAP2L suppressed cell proliferation, impaired monolayer formation, inhibited cell invasion. CKAP2L was confirmed to be the direct target of miR-326, which had a carcinostatic effect by binding the 3'untranslated regions (3'UTRs) of CKAP2L mRNA. The deletion of CKAP2L resulted in reduced expression of genes involved in the mitotic cell cycle such as multiple cyclin-dependent kinases and cyclins, but also several genes encoding proteins involved in chromosome segregation and spindle assembly. CONCLUSION: Taken together, CKAP2L plays a carcinogenic role in prostate cancer by regulates the expression of cycle-associated proteins.

CKAP2L, transcriptionally inhibited by FOXP3, promotes breast carcinogenesis through the AKT/mTOR pathway.

Cytoskeleton-associated protein 2-like (CKAP2L) is a mitotic spindle protein and its high expression is reported to be associated with the poor prognosis of cancer patients. Interestingly, TNMplot website analysis indicated that CKAP2L expression was significantly higher in breast cancer (BC) tissues than in normal breast tissues (P < 0.001). Thus, this study was conducted to investigate the role of CKAP2L in breast carcinogenesis and its underlying molecular mechanisms. The mRNA and protein expression levels of CKAP2L in 40 paired fresh BC and para-carcinoma specimens were first analyzed, and the results confirmed the high expression of CKAP2L in BC tissues. Functional studies revealed that CKAP2L silencing dramatically suppressed the proliferation, migration, and invasion, induced cell cycle arrest and apoptosis of BC cells in vitro, and inhibited the growth of xenografted tumors in vivo. However, CKAP2L overexpression produced the opposite results. Mechanically, CKAP2L could activate the AKT/mTOR signaling pathway in BC cells accompanied by increased phosphorylation levels of AKT, mTOR, and p70S6K in CKAP2L-overexpressed cells. Forkhead box protein P3 (FOXP3), a transcription factor with tumor-suppressive properties, was proved to negatively regulate CKAP2L expression in BC cells through binding to the promoter of CKAP2L and inhibiting its transcription. In summary, the present study demonstrates that CKAP2L, transcriptionally regulated by FOXP3, activates the AKT/mTOR signaling pathway and promotes breast carcinogenesis. CKAP2L may serve as a promising target of therapeutic intervention for BC.

Prognostic significance of CKAP2L expression in patients with clear cell renal cell carcinoma.

Background: Cytoskeleton-associated protein 2-like protein (CKAP2L) is thought to promote the progression of glioma, breast cancer, and ovarian cancer. However, the role of cytoskeleton-associated protein 2-like protein in clear cell renal cell carcinoma (ccRCC) is still unclear. The study aimed to investigate the roles and mechanisms of cytoskeleton-associated protein 2-like protein in clear cell renal cell carcinoma. Methods: The level of cytoskeleton-associated protein 2-like protein in tumors was explored by using UALCAN and Oncomine databases. Gene expression datasets of clear cell renal cell carcinoma from The Cancer Genome Atlas and Gene Expression Omnibus (GEO) were also used to validate the cytoskeleton-associated protein 2-like protein level in clear cell renal cell carcinoma. Survival analysis was performed to investigate the relationship between cytoskeleton-associated protein 2-like protein level and prognosis of clear cell renal cell carcinoma patients. Cox regression analysis was used for identifying the independent prognostic factors. Gene set enrichment analysis (GSEA), gene set variation analysis (GSVA), protein-protein interaction analysis, co-expression analysis, and immune infiltration analysis were used to explore the potential mechanisms of cytoskeleton-associated protein 2-like protein in clear cell renal cell carcinoma. Moreover, the levels of cytoskeleton-associated protein 2-like protein in clinical clear cell renal cell carcinoma tissues were also measured using RT-PCR, immunohistochemical analysis, and Western blotting. M1 macrophages and CD4+ T cells were also detected by immunohistochemistry between tumor and normal tissues. Results: The level of cytoskeleton-associated protein 2-like protein was upregulated in clear cell renal cell carcinoma according to multiple databases and experimental verification. Upregulated cytoskeleton-associated protein 2-like protein is an independent prognostic factor, which might activate the JAK-STAT signaling pathway, the P53 signaling pathway, the TGF-ß signaling pathway, the WNT signaling pathway, etc., in clear cell renal cell carcinoma. Protein-protein interaction analysis and co-expression analysis suggest that cytoskeleton-associated protein 2-like protein might interact with some proliferation proteins. Immune infiltration analysis indicates that cytoskeleton-associated protein 2-like protein may affect the level of activated CD4+ memory T cells, M1 macrophages, CD8+ T cells, and neutrophils in clear cell renal cell carcinoma. More M1 macrophage infiltrations in tumor tissues with higher cytoskeleton-associated protein 2-like protein were validated by clear cell renal cell carcinoma tumor tissues. Conclusion: Cytoskeleton-associated protein 2-like protein is upregulated in clear cell renal cell carcinoma tissues, which may promote progression of the disease. Cytoskeleton-associated protein 2-like protein is a potential target for prognostic markers and a potential treatment target in clear cell renal cell carcinoma.

Identification of a novel pathogenic variant in CKAP2L and literature review in a child with Filippi syndrome and congenital talipes equinovarus.

Filippi syndrome (MIM #272440), one of the craniodigital syndromes, is a rare genetic entity with autosomal recessive inheritance and characterized by pre- and postnatal growth retardation, microcephaly, distinctive facial appearance, developmental delay/intellectual disability, and variable syndactylies of the fingers and toes. In this report, a further female patient of Filippi syndrome who additionally had a unilateral congenital talipes equinovarus (CTEV), a feature not previously recorded, is described. Genetic testing revealed a novel homozygous frameshift pathogenic variant (c.552_555delCAAA, p.Asn184Lysfs*8) in CKAP2L and thus confirmed the diagnosis of Filippi syndrome. We hope that the newly recognized feature (CTEV) will contribute to expand the clinical spectrum of this extremely rare condition. In view of the paucity of reported cases, the full spectrum of clinical findings of Filippi syndrome necessitates obviously further affected individuals/pedigrees delineation in order to elucidate the etiological and phenotypic aspects of this orphan disease appropriately.

CKAP2L Knockdown Exerts Antitumor Effects by Increasing miR-4496 in Glioblastoma Cell Lines.

Despite advances in the diagnosis and treatment of the central nervous system malignancy glioma, overall survival remains poor. Cytoskeleton-associated protein 2-like (CKAP2L), which plays key roles in neural progenitor cell division, has also been linked to poor prognosis in lung cancer. In the present study, we investigated the role of CKAP2L in glioma. From bioinformatics analyses of datasets from The Cancer Gene Atlas and the Chinese Glioma Genome Atlas, we found that CKAP2L expression correlates with tumor grade and overall survival. Gene set enrichment analysis (GSEA) showed that MITOTIC_SPINDLE, G2M_CHECKPOINT, and E2F_TARGETS are crucially enriched phenotypes associated with high CKAP2L expression. Using U87MG, U118MG, and LNZ308 human glioma cells, we confirmed that CKAP2L knockdown with siCKAP2L inhibits glioma cell proliferation, migration, invasion, and epithelial-mesenchymal transition. Interestingly, CKAP2L knockdown also induced cell cycle arrest at G2/M phase, which is consistent with the GSEA finding. Finally, we observed that CKAP2L knockdown led to significant increases in miR-4496. Treating cells with exogenous miR-4496 mimicked the effect of CKAP2L knockdown, and the effects of CKAP2L knockdown could be suppressed by miR-4496 inhibition. These findings suggest that CKAP2L is a vital regulator of miR-4496 activity and that CKAP2L is a potentially useful prognostic marker in glioma.

Oncogenic and prognostic role of CKAP2L in hepatocellular carcinoma.

Cytoskeleton-associated protein 2-like (CKAP2L) exerts crucial function in the cell-cycle progression and mitotic spindle formation of neural stem/progenitor cells. However, in hepatocellular carcinoma (HCC), the expression pattern, clinical significance and biologic role of CKAP2L remain unexplored. We analysed The Cancer Genome Atlas (TCGA) database and found that CKAP2L was dramatically upregulated in HCC tissues at the mRNA level compared to adjacent tissues, which was validated in 48 paired HCC and para-tumor tissues using quantitative real-time PCR (qRT-PCR). Immunohistochemical analysis of tissue microarray revealed that CKAP2L was also significantly overexpressed at the protein level. Further clinical and survival analysis of the TCGA cohort revealed that increased CKAP2L expression was strongly associated with reduced overall survival. We further validated that higher CKAP2L protein expression was associated with worse prognosis in the Peking Union Medical College Hospital (PUMCH) cohort. Univariate and multivariate Cox regression analyses in the TCGA and PUMCH cohort suggested that CKAP2L overexpression was an independent risk factor for poor prognosis in HCC patients. Then, we validated that CKAP2L silencing inhibited HCC cell proliferation, migration, and invasion abilities. Knockdown of CKAP2L in Huh7 cells suppressed the growth of xenograft tumors in vivo. Furthermore, qRT-PCR and western blotting results demonstrated that the expression of Class I Phosphoinositide 3-Kinase PIK3CA/p110α and PIK3CB/p110ß isoforms reduced obviously in Huh7 cells after depleting CKAP2L. This study demonstrated for the first time that high CKAP2L expression in HCC tissues is significantly correlated with poor prognosis in HCC patients and greatly facilitate the malignancy of HCC, thus providing a new prognostic biomarker and potential therapeutic target.

Up-regulation of CKAP2L expression promotes lung adenocarcinoma invasion and is associated with poor prognosis.

AIM: The purpose of this study is to consider the function of cytoskeleton-associated protein 2-like (CKAP2L) in lung adenocarcinoma (LAD) development and its prognostic value. METHODS: The mRNA expression of CKAP2L and its correlation with clinical factors in LAD patients were analyzed from the data taken from The Cancer Genome Atlas and The First Affiliated Hospital of Kunming Medical University. We constructed H460 and A549 cell lines with silenced CKAP2L using RNA interference. Cell counting kit-8 assay and colony formation assays were carried out to determine the function of CKAP2L in H460 and A549 cell proliferation. Transwell and wound healing assays were applied to determine the effect of CKAP2L on H460 and A549 cell invasion and migration. The influences of CKAP2L on mitogen-activated protein kinase signaling pathway-related proteins were tested by Western blotting. RESULTS: CKAP2L expression is enhanced in LAD tissues and is predictive of poor prognosis in LAD patients. High expression of CKAP2L is associated with stage (P<0.001), lymph node status (P=0.002), and metastasis (P=0.025). Depletion of CKAP2L dramatically suppressed the proliferation, migration, and invasion of H460 and A549 cells. Moreover, the ratio of p-MEK/ MEK and p-ERK/ERK reduced obviously in A549 cells after depleting CKAP2L. CONCLUSION: Our findings implied that CKAP2L might be a promoter of LAD and could serve as a predictor for LAD patients.