Expression of Spindle and Kinetochore-Associated Protein 1 Is Associated with Poor Prognosis in Papillary Thyroid Carcinoma

Pancancer analysis of SKA1 mutation and its association with the diagnosis and prognosis of human cancers

This study aims to explore the role of SKA1 in cancer diagnosis and prognosis and to investigate the mechanism by which SKA1 affects the malignant behaviors of ovarian cancer. Herein, we analyzed the oncogenic role of SKA1 at pan-cancer level by multiple informatics databases and verified the analysis by in vitro experiments. As a result, SKA1 was upregulated across cancers and was related to poor clinical outcome and immune infiltration. Specifically, the constructed nomogram showed superior performance in predicting the prognosis of epithelial ovarian cancer patients. Furthermore, the in vitro experiments revealed that silencing SKA1 significantly inhibited the proliferation, migratory ability and enhanced the cisplatin sensitivity of ovarian cancer cells. Therefore, we explored the oncogenic and potential therapeutic role of SKA1 across cancers through multiple bioinformatic analysis and revealed that SKA1 may promote ovarian cancer progression and chemoresistance to cisplatin by activating the AKT-FOXO3a signaling pathway.

SKA1 promotes tumor metastasis via SAFB-mediated transcription repression of DUSP6 in clear cell renal cell carcinoma

The most hostile form of urologic cancer, clear cell renal cell carcinoma (ccRCC), has a high fatality rate and poor prognosis due to tumor metastasis at initial presentation. The complex process driving ccRCC metastasis is still unknown, though. In this study, we demonstrate that Spindle and kinetochore-associated protein 1 (SKA1) expression is significantly upregulated in ccRCC tissues and associated with aggressive clinicopathologic characteristics. Functionally, SKA1 knockdown on ccRCC cells reduced cancer cell motility both in vivo and in vitro research. These bioactivities of SKA1 may be brought on by its specific interaction with scaffold attachment factor B, according to the proposed mechanism (SAFB), which could further depress the transcription of dual specificity phosphatase 6 (DUSP6). Our findings may provide a new way of researching SKA1-regulated tumor metastasis, and indicate that SKA1 is a prospective therapeutic target for renal carcinoma.

Identification of HCG18 and MCM3AP-AS1 That Associate With Bone Metastasis, Poor Prognosis and Increased Abundance of M2 Macrophage Infiltration in Prostate Cancer

Background:

Bone metastasis is a leading cause of the high mortality rate of prostate cancer (PCa), but curative strategies remain lacking. Recent studies suggest long non-coding RNAs (lncRNAs) may be potential targets to develop drugs. However, PCa bone metastasis-specifically-related lncRNAs were rarely reported. This study aimed to identify crucial lncRNAs and reveal their function mechanisms.

Methods:

GSE32269 and GSE26964 microarray datasets, downloaded from the Gene Expression Omnibus database, were used to analyze differentially expressed genes (DEGs)/lncRNAs (DELs) and miRNAs (DEMs), respectively. Weighted gene co-expression network analysis was performed to screen PCa bone metastasis-associated modules. The co-expression and competing endogenous RNAs (ceRNAs) networks were constructed to identify hub lncRNAs. Univariate Cox regression analysis was conducted to determine their prognostic values. The correlation of lncRNAs with immune infiltrating cells was analyzed by using Tumor IMmune Estimation Resource. Therapeutic drugs were predicted by querying the Connectivity Map (CMap) and the Comparative Toxicogenomics Database (CTD).

Results:

A total of 18 DELs, 2,614 DEGs and 86 DEMs were screened between bone metastatic and primary PCa samples. Four modules enriched by DEGs were shown to be bone metastasis-associated. LncRNA HCG18 and MCM3AP-AS1 were identified to be important because they existed in both of the co-expression and ceRNA networks (forming the relationship pairs: HCG18/MCM3AP-AS1-KNTC1, MCM3AP-AS1-hsa-miR-508-3p-DTL and HCG18/MCM3AP-AS1-hsa-miR-127-3p-CDKN3). All the genes in these interaction pairs were significantly associated with overall survival of PCa patients. Also, HCG18, MCM3AP-AS1 and their target mRNAs were positively correlated with various tumor-infiltrated immune cells, especially increased M2 macrophages. Valproic acid and trichostatin A may be effective to treat PCa bone metastasis by targeting HCG18 and MCM3AP-AS1.

Conclusion:

HCG18 and MCM3AP-AS1 that regulate M2 macrophage infiltration may be important targets to treat PCa bone metastasis and improve prognosis.

SKA1 expression in oral squamous cell carcinoma and its relationship to P53 and clinicopathologic features

In this study, 57 paraffin-embedded tissue specimens from patients with oral squamous cell carcinoma (OSCC) were collected and analyzed. Spindle and kinetochore-associated complex subunit 1 (SKA1) and P53 protein expression in selected samples was detected by immunohistochemistry. The positive expression rate of SKA1 and P53 was significantly higher in oral squamous cell carcinoma tissues than in normal controls. The expression of SKA1 protein was significantly associated with tumor-node-metastasis (TNM) stage, and p53 expression was significantly correlated with pathologic differentiation grade in oral squamous cell carcinoma tissues. There was a significant correlation between SKA1 and p53 protein expression in oral squamous cell carcinoma tissues. Our results indicate that the SKA1 gene might be involved in the development of oral squamous cell carcinoma and might predict its prognosis. SKA1 is expected to be a new molecular target for oral squamous cell carcinoma.

SKA1 promotes malignant phenotype and progression of glioma via multiple signaling pathways

Background

Spindle and kinetochore associated protein 1 (SKA1) is a protein involved in chromosome congression and mitosis. It has been found to be upregulated and oncogenic in several human cancers. Herein, we investigated the precise role of SKA1 in the progression and malignant phenotype of human glioma.

Methods

Bioinformatic analysis was carried out based on the RNA-seq data and corresponding clinical data from GEO, TCGA and CGGA databases. Western blot was performed to analyze the expression of SKA1 in clinical samples and signaling pathway proteins in glioma cells, respectively. CCK8 assay, colony forming assay and EdU assay were performed to assess the cell viability. Cell migration and invasion assays were also performed. Moreover, xenograft model was established and the expression of SKA1 was assessed in the xenograft by immunohistochemistry.

Results

SKA1 expression is positively correlated with glioma grade and could be a promising biomarker for GBM. Moreover, overexpression of SKA1 may lead to poor prognosis in glioma. Downregulation of SKA1 attenuated cell viability, migration, and invasion in U251, U87, LN229 and T98 cells. Furthermore, GSEA analysis demonstrated that SKA1 was involved in the cell cycle, EMT pathway as well as Wnt/β-catenin signaling pathway, which were then confirmed with Western blot analysis.

Conclusion

SKA1 promotes malignant phenotype and progression of glioma via multiple pathways, including cell cycle, EMT, Wnt/β-catenin signaling pathway. Therefore, SKA1 could be a promising therapeutic target for the treatment of human gliomas.

SKA1 overexpression is associated with the prognosis of esophageal squamous cell carcinoma and regulates cell proliferation and migration

Spindle and kinetochore‑associated protein 1 (SKA1), a microtubule‑binding subcomplex of the outer kinetochore, is essential for complete chromosomal separation. SKA1 has been suggested as a potential biomarker for various types of cancer. However, the exact role of SKA1 in esophageal squamous cell carcinoma (ESCC) remains unclear. The present study investigated whether SKA1 affects the biological behavior of ESCC. The expression of SKA1 in ESCC tissues was measured using immunohistochemistry and reverse transcription‑quantitative polymerase chain reaction. In addition, a SKA1‑silencing lentivirus was constructed, which was transfected into TE‑1 cells to establish stable SKA1‑knockdown TE‑1 cells. Proliferation was analyzed using a Celigo image cytometer and a MTS assay. Cell cycle progression and apoptosis were analyzed by flow cytometry, while cell migration was assessed using a Transwell assay. SKA1 was significantly overexpressed in ESCC tissues, and SKA1 overexpression was significantly associated with differentiation, pathological N stage and pathological tumor‑node‑metastasis stage. SKA1 was determined to be an independent prognostic factor for ESCC. Furthermore, SKA1 was significantly overexpressed in ESCC cells, and SKA1‑silencing inhibited cell proliferation and migration, arrested the cell cycle and promoted cell apoptosis. In summary, SKA1 may serve as a potential therapeutic target and prognostic biomarker for ESCC.

Kinetochore Recruitment of the Spindle and Kinetochore-Associated (Ska) Complex Is Regulated by Centrosomal PP2A in Caenorhabditis elegans

During mitosis, kinetochore-microtubule interactions ensure that chromosomes are accurately segregated to daughter cells. RSA-1 (regulator of spindle assembly-1) is a regulatory B″ subunit of protein phosphatase 2A that was previously proposed to modulate microtubule dynamics during spindle assembly. We have identified a genetic interaction between the centrosomal protein, RSA-1, and the spindle- and kinetochore-associated (Ska) complex in Caenorhabditis elegans In a forward genetic screen for suppressors of rsa-1(or598) embryonic lethality, we identified mutations in ska-1 and ska-3 Loss of SKA-1 and SKA-3, as well as components of the KMN (KNL-1/MIS-12/NDC-80) complex and the microtubule end-binding protein EBP-2, all suppressed the embryonic lethality of rsa-1(or598) These suppressors also disrupted the intracellular localization of the Ska complex, revealing a network of proteins that influence Ska function during mitosis. In rsa-1(or598) embryos, SKA-1 is excessively and prematurely recruited to kinetochores during spindle assembly, but SKA-1 levels return to normal just prior to anaphase onset. Loss of the TPX2 homolog, TPXL-1, also resulted in overrecruitment of SKA-1 to the kinetochores and this correlated with the loss of Aurora A kinase on the spindle microtubules. We propose that rsa-1 regulates the kinetochore localization of the Ska complex, with spindle-associated Aurora A acting as a potential mediator. These data reveal a novel mechanism of protein phosphatase 2A function during mitosis involving a centrosome-based regulatory mechanism for Ska complex recruitment to the kinetochore.

SKA1 overexpression is associated with poor prognosis in hepatocellular carcinoma

BACKGROUND

SKA1, an important mitosis protein, has been indicated in the initiation and progression of several malignancies. However, its clinical significance in hepatocellular carcinoma (HCC) remain to be elucidated.

METHODS

mRNA expression of SKA1 was examined in 126 HCC and paired non-neoplastic tissues using real-time PCR and validated in The Cancer Genome Atlas (TCGA) database. SKA1 protein expression was detected using immunohistochemistry in the 126 HCC tissues and its associations with clinicopathological parameters and prognosis were analyzed. Hierarchical cluster analysis and gene set enrichment analysis (GSEA) were performed in selected Gene Expression Omnibus data sets.

RESULTS

SKA1 mRNA expression was significantly elevated in HCC tissues from both local hospital and TCGA database. Immunohistochemistry revealed that increased SKA1 expression was present in 65 of the 126 cases and was significantly associated with higher serum alpha-fetoprotein concentration, larger tumor size and higher TNM stage. Patients with positive SKA1 expression showed significantly worse overall and relapse-free survival. Multivariate Cox regression analysis revealed that SKA1 was an independent predictor of patient prognosis. Gene expression profiling analysis of public data showed that high-SKA1 expression HCC tissues had similar gene expression profiles with fetal liver tissues. Moreover, GSEA showed that genes up-regulated in high SKA1 HCC subgroup were significantly enriched in cell cycle pathway, while genes down-regulated were significantly enriched in apoptosis pathway.

CONCLUSIONS

Our findings indicate that the oncofetal gene SKA1 might be involved in the progression of the HCC and could serve as a prognostic marker for HCC.

Targeting mitotic pathways for endocrine-related cancer therapeutics

A colossal amount of basic research over the past few decades has provided unprecedented insights into the highly complex process of cell division. There is an ever-expanding catalog of proteins that orchestrate, participate and coordinate in the exquisite processes of spindle formation, chromosome dynamics and the formation and regulation of kinetochore microtubule attachments. Use of classical microtubule poisons has still been widely and often successfully used to combat a variety of cancers, but their non-selective interference in other crucial physiologic processes necessitate the identification of novel druggable components specific to the cell cycle/division pathway. Considering cell cycle deregulation, unscheduled proliferation, genomic instability and chromosomal instability as a hallmark of tumor cells, there lies an enormous untapped terrain that needs to be unearthed before a drug can pave its way from bench to bedside. This review attempts to systematically summarize the advances made in this context so far with an emphasis on endocrine-related cancers and the avenues for future progress to target mitotic mechanisms in an effort to combat these dreadful cancers.

Regulation of spindle and kinetochore-associated protein 1 by antitumor miR-10a-5p in renal cell carcinoma

Analysis of our original microRNA (miRNA) expression signature of patients with advanced renal cell carcinoma (RCC) showed that microRNA‐10a‐5p (miR‐10a‐5p) was significantly downregulated in RCC specimens. The aims of the present study were to investigate the antitumor roles of miR‐10a‐5p and the novel cancer networks regulated by this miRNA in RCC cells. Downregulation of miR‐10a‐5p was confirmed in RCC tissues and RCC tissues from patients treated with tyrosine kinase inhibitors (TKI). Ectopic expression of miR‐10a‐5p in RCC cell lines (786‐O and A498 cells) inhibited cancer cell migration and invasion. Spindle and kinetochore‐associated protein 1 (SKA1) was identified as an antitumor miR‐10a‐5p target by genome‐based approaches, and direct regulation was validated by luciferase reporter assays. Knockdown of SKA1 inhibited cancer cell migration and invasion in RCC cells. Overexpression of SKA1 was observed in RCC tissues and TKI‐treated RCC tissues. Moreover, analysis of The Cancer Genome Atlas database demonstrated that low expression of miR‐10a‐5p and high expression of SKA1 were significantly associated with overall survival in patients with RCC. These findings showed that downregulation of miR‐10a‐5p and overexpression of the SKA1 axis were highly involved in RCC pathogenesis and resistance to TKI treatment in RCC.

Hypoxia promotes chemotherapy resistance by down-regulating SKA1 gene expression in human osteosarcoma

Drug resistance has always been the main problem in osteosarcoma treatment, and hypoxia seems to be one of the many causes for drug resistance. Therefore, in this study, we investigated how hypoxia triggers chemotherapy resistance in osteosarcoma. We first screened hypoxia- and normoxia- cultured osteosarcoma cells in silico to identify the differentially expressed genes specifically related to drug resistance. This led to the identification of spindle and kinetochore associated complex subunit 1 (SKA1) as a probable gene of interest. SKA1 was further overexpressed by a lentiviral vector into an osteosarcoma cell line to study its role in chemoresistance. Our data revealed that SKA1 overexpression reduced the expression of some multidrug resistance genes, and enhanced the sensitivity of two common chemotherapeutic drugs used in osteosarcoma patients, epirubicin (EPI) and ifosfamide (IFO). In addition, we also confirmed the role of SKA1 in EPI drug sensitivity in vivo. Taken together, our study indicated that hypoxia mediated downregulation of SKA1 expression increased the chemotherapy resistance in human osteosarcoma cells.

SKA1 regulates the metastasis and cisplatin resistance of non-small cell lung cancer

Currently, chemotherapy with platinum-based drugs including cisplatin is the most effective therapy for the treatment of non-small cell lung carcinoma (NSCLC). However, the efficacy of chemotherapy is limited due to commonly developed drug resistance. Spindle and kinetochore-associated complex subunit 1 (SKA1) is part of a complex essential for stabilizing the attachment of spindle microtubules to kinetochores and for maintaining the metaphase plate during mitosis. In the present study, we aimed to investigate the role of SKA1 in the process of metastasis and drug resistance of NSCLC. We completed a series of experiments to investigate the function of SKA1 in NSCLC metastasis and drug resistance including qRT-PCR, immunohistochemistry and western blotting, as well as MTT, BrdU, wounded healing, Transwell and gelatin zymography assays. We demonstrated that the expression levels of SKA1 were elevated in NSCLC and were correlated with cancer progression and malignancy. We also reported that SKA1 positively regulated the proliferation and metastatic ability of NSCLC cells. In addition, we determined that SKA1 contributed to cisplatin resistance in NSCLC cells by protecting these cells from cisplatin-induced cell apoptosis. SKA1 also appeared to regulate the ERK1/2 and the Akt-mediated signaling pathways in NSCLC cells. SKA1 is required for metastasis and cisplatin resistance of non-small cell lung cancer.