TPX2 Knockdown Research Articles

TPX2 upregulates MMP13 to promote the progression of lipopolysaccharide-induced osteoarthritis.

This study seeks to identify potential clinical biomarkers for osteoarthritis (OA) using bioinformatics and investigate OA mechanisms through cellular assays. Differentially Expressed Genes (DEGs) from GSE52042 (four OA samples, four control samples) were screened and analyzed with protein-protein interaction (PPI) analysis. Overlapping genes in GSE52042 and GSE206848 (seven OA samples, and seven control samples) were identified and evaluated using Gene Set Enrichment Analysis (GSEA) and clinical diagnostic value analysis to determine the hub gene. Finally, whether and how the hub gene impacts LPS-induced OA progression was explored by in vitro experiments, including Western blotting (WB), co-immunoprecipitation (Co-IP), flow cytometry, etc. Bioinformatics analysis of DEGs (142 up-regulated and 171 down-regulated) in GSE52042 identified two overlapping genes (U2AF2, TPX2) that exhibit significant clinical diagnostic value. These genes are up-regulated in OA samples from both GSE52042 and GSE206848 datasets. Notably, TPX2, which AUC = 0.873 was identified as the hub gene. In vitro experiments have demonstrated that silencing TPX2 can alleviate damage to chondrocytes induced by lipopolysaccharide (LPS). Furthermore, there is a protein interaction between TPX2 and MMP13 in OA. Excessive MMP13 can attenuate the effects of TPX2 knockdown on LPS-induced changes in OA protein expression, cell growth, and apoptosis. In conclusion, our findings shed light on the molecular mechanisms of OA and suggested TPX2 as a potential therapeutic target. TPX2 could promote the progression of LPS-induced OA by up-regulating the expression of MMP13, which provides some implications for clinical research.

Abstract 2517: The amplification of TPX2 is a potential biomarker of oxaliplatin-sensitivity of colorectal cancers (CRCs) with CIN phenotype

Abstract The amplification of Chr20q11.21 harboring TPX2 gene is the most frequent copy number alteration among the cases of colorectal cancers (CRCs), especially left-sided ones. We retrospectively examined 2828 cases of CRC patients who took cancer-genome panel tests in Japan between June 2019 and November 2022. The time to first-line treatment failure was longer with regimen with oxaliplatin than with those with irinotecan in CRC patients with Chr20q11,21 amplification (12.2 versus 9.2 months, p=0.0481). Oxaliplatin induces double-strand breaks (DSBs) and then cellular apoptosis. A key event of the DNA damage response to DSBs for cellular survival is the extensive phosphorylation of Ser139 of Histone H2AX adjacent to the chromosomal break. TPX2 whose gene resides in Chr20q11,21 has been reported to repress the phosphorylation of H2AX upon ionizing radiation. The purpose of this study is to identify the relationship between the amplification of TPX2 and oxaliplatin sensitivity in human CRCs. The knockdown of TPX2 decreased the oxaliplatin-susceptibility of COLO320 and Caco-2, CIN phenotype CRC cell lines which highly expressed TPX2. However, TPX2 knockdown did not reduce the oxaliplatin sensitivity of HCT-116, an MSI phenotype CRC cell line with low-level of TPX2 expression. The knockdown of TPX2 in CIN phenotype CRC cells, not in the MSI phenotype CRC cells, enhanced the phosphorylation of H2AX upon the DNA-damage induced by oxaliplatin. These findings suggest that amplification of TPX2 contributes to the oxaliplatin-susceptibility of CRCs with CIN phenotype through DNA repair machinery. Citation Format: Shohei Ueno, Taichi Isobe, Ryosuke Taguchi, Kenji Tsuchihashi, Koichi Akashi, Eishi Baba. The amplification of TPX2 is a potential biomarker of oxaliplatin-sensitivity of colorectal cancers (CRCs) with CIN phenotype [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2517.

Integrative analysis confirms TPX2 as a novel biomarker for clinical implication, tumor microenvironment, and immunotherapy response across human solid tumors.

Targeting Protein for Xenopus Kinesin Like Protein 2 (TPX2) serves as a microtubule associated protein for the regulation of spindle assembly and tumorigenesis. We aim to investigate the prognostic and immunological role of TPX2 in pan-cancer. TCGA database, Tumor Immune Single-cell Hub (TISCH), and Human Protein Atlas (HPA) were retrieved to evaluate the expression pattern of TPX2 as well as its diagnostic and prognostic value in solid tumors. Genomic alterations of TPX2 were assessed with cBioPortal database. In vitro experiments in lung adenocarcinoma (LUAD) were performed to confirm the potential role of TPX2. Overexpression of TPX2 was found in 22 types of cancers, and was positively related with copy number variations (CNV) and negative with methylation. Up-regulated TPX2 could predict worse outcomes in the majority of cancers. Single-cell analysis revealed that TPX2 was mainly distributed in malignant cells (especially in glioma) and proliferating T cells. Genomic alteration of TPX2 was common in different types of tumors, while with prognostic value in two types of cancers. Additionally, significant correlations were found between TPX2 expression and tumor microenvironment (including stromal cells and immune cells) as well as immune related genes across cancer types. Drug sensitivity analysis revealed that TPX2 could predict response to chemotherapy and immunotherapy. Functional analyses demonstrated close relationship of TPX2 with immune function and malignant phenotypes. Finally, it was confirmed that knockdown of TPX2 could reduce proliferation and migration ability of LUAD cells. In summary, TPX2 could serve as a diagnostic and prognostic biomarker and a potential immunotherapy marker.

MiR-218-5p Targeting TPX2 Regulates p53 Pathway and Inhibits Malignant Progression of Lung Adenocarcinoma

Lung adenocarcinoma (LUAD) is a major subtype of lung cancer, and its treatment and diagnosis remain a hot research topic. Targeting protein for Xenopus kinesin-like protein 2 (TPX2) is highly expressed in a variety of cancer cells and may be associated with the progression of LUAD. This study aimed to investigate the effect of TPX2 on the malignant progression of LUAD cells and the regulatory mechanisms. The expression of gene TPX2 in LUAD tissues from The Cancer Genome Atlas (TCGA) database was analyzed by bioinformatics analysis techniques. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression levels of TPX2 and miR-218-5p in human lung normal cell lines and human LUAD cell lines. Western blot was used to detect TPX2 protein expression in cell lines and its effect on the expression of key proteins in the p53 signaling pathway. The relationship between TPX2 and miR-218-5p was predicted using bioinformatics and verified by dual luciferase reporter gene assay. Cell counting kit-8 (CCK-8) assay, cell clone formation, cell scratching, Transwell assay, and flow cytometry were used to detect the effects of miR-218-5p and TPX2 on LUAD cell function. TPX2 was significantly overexpressed in LUAD cells, and knockdown of TPX2 inhibited LUAD cell proliferation, migration, and invasion, promoted apoptosis and induced G2/M phase block, and promoted the expression of key proteins in the p53 signaling pathway. miR-218-5p, an upstream regulator of TPX2, could inhibit its expression. Overexpression of miR-218-5p eliminated the malignant development caused by high expression of TPX2, inhibited the malignant processes of LUAD cells such as proliferation and migration as well as promoted the p53 signaling pathway. miR-218-5p targets and inhibits TPX2 expression and exerts an inhibitory effect on the malignant progression of LUAD cells via p53.

Integrated bioinformatical and in vitro study on drug targets for liver cirrhosis based on unsupervised consensus clustering and immune cell infiltration.

Liver cirrhosis is one of the most common cause of death in the world. The progress of liver cirrhosis involves health, liver cirrhosis and liver cancer, leading to great challenges in the diagnosis of the disease. Drug targets, which could be obtained conveniently, can help clinicians improve prognosis and treatment. Liver cirrhosis is associated with serum calcium levels. And studies reported Tanshinone IIA plays a therapeutic role in liver injury through activating calcium-dependent apoptosis. In this study, we explored the diagnostic key targets of Tanshinone IIA in liver cirrhosis through exploration of comprehensive dataset including health, liver cirrhosis and liver cancer patients. The unsupervised consensus clustering algorithm identified 3 novel subtypes in which differentially expressed genes (DEGs) between both subtypes were found by pairwise comparison. Then, 4 key drug targets of Tanshinone IIA were determined through the intersection of these DEGs. The diagnostic performance of target genes was assessed and further verified in the external dataset. We found that the 4 key drug targets could be used as effective diagnostic biomarkers. Then the immune scores in the high and low expression groups of target genes were estimated to identify significantly expressed immune cells. In addition, the immune infiltration of high and low target gene expression groups in several immune cells were significantly different. The findings suggest that 4 key drug targets may be a simple and useful diagnostic tool for predicting patients with cirrhosis. We further studied the carcinogenesis role of AKR1C3 and TPX2 in vitro. Both mRNA and protein expression in hepatoma carcinoma cells was detected using qRT-PCR and Western blot. And the knockdown of AKR1C3 and TPX2 significantly suppressed cell proliferation, migration and invasion.

MiRNA-27b-3p/TPX2 Axis Regulates Clear Cell Renal Cell Carcinoma Cell Proliferation, Invasion and Migration.

There is a wide variety of cancer cells that can be linked to the presence of TPX2. However, there is not a lot of evidence regarding its role in the development and maintenance of clear cell renal cell carcinoma (ccRCC). In our study, bioinformatics analysis was performed to obtain differentially expressed mRNAs and miR-NAs in ccRCC. Survival curves predicted correlation of TPX2 expression with patient survival. The upstream regulatory miRNA of TPX2 was predicted to be miRNA-27b-3p through database, and dual luciferase assay verified the targeted relationship. qRT-PCR and Western blot were employed for examination of TPX2 mRNA and protein expression in ccRCC cells. Proliferation, invasion, migration and cell cycle were detected by CCK-8, colony formation, wound healing, Transwell, and flow cytometry assays. The results showed that TPX2 showed very high expression in ccRCC, and patients with higher TPX2 expression had shorter relative survival. Low miRNA-27b-3p expression was found in ccRCC. Knockdown of TPX2 or forced expression of miRNA-27b-3p in ccRCC cells inhibited cell proliferation, migration, invasion, and arrested cell division in G0/G1 phase. Dual luciferase reporter presented that miRNA-27b-3p targeted TPX2 to inhibit its expression. Rescue experiments demonstrated that the miRNA-27b-3p/ TPX2 axis affected the biological functions of ccRCC cells. Concurrent overexpression of miRNA-27b-3p and TPX2 inhibited the facilitating effect of TPX2 on ccRCC cell growth. The results revealed novel regulatory mechanisms involved in ccRCC progression, hoping that it may spark an insight for later discovery about the new therapeutic targets for ccRCC.

MiR-29c Suppresses the Malignant Phenotype of Hepatocellular Carcinoma Cells In Vitro by Mediating TPX2 Associated with Immune Infiltration.

miR-29-3p, an important tumor suppressor, with inhibitory effects in multiple cancers that have been studied. Its exact molecular function is in HCC, however, still not been explored clearly. The purpose of our study is to make certain how miR-29c-3p affects HCC through TPX2. Expression profile data of miR-29c-3p and TPX2 were acquired and downloaded from the TCGA database, and the respective differential expression was verified by qPCR and immunohistochemistry. The StarBase and dual luciferase reporter confirmed TPX2 targeting miR-29c-3p. Their effects on the biological functions of Hep3B and HepG2 were investigated by cellular assays. miR-29-3p was found to be significantly down-regulated in HCC, and the miR-29-3p low expression group had a poor prognosis. Overexpression of miR-29-3p was detrimental to invasion and migration ability of HCC cells and promoted their apoptosis. We identified miR-29c-3p targeting TPX2 by predictive analysis. TPX2 was significantly upregulated in HCC, and patients with high TPX2 expression had a poor prognosis. TPX2 knockdown partially counteracted the promoting effect of miR-29-3p inhibition on hepatocellular carcinoma cells, and its effect on hepatocellular carcinoma cell biology was similar to miR-29c-3p overexpression. miR-29c, a key gene regulating HCC, is lowly expressed in HCC, its overexpression can remarkably inhibit the biological function of tumor cells. miR-29c can perform this function by regulating the expression of TPX2.

TPX2 regulated by miR-29c-3p induces cell proliferation in osteosarcoma via the AKT signaling pathway.

The present study aimed to investigate the significance of targeting protein for Xenopus kinesin-like protein 2 (TPX2) expression in osteosarcoma. First, the TPX2 expression and survival analysis data were evaluated from The Cancer Genome Atlas (TCGA) database. Next, reverse transcription-quantitative PCR was used to explore the expression of TPX2 in osteosarcoma tissues. The observed potential target relationship between TPX2 and microRNA (miR)-29c-3p was verified using TargetScan and luciferase reporter assays. Kaplan-Meier survival analysis was used to determine associations between TPX2 expression levels and survival prognosis. TPX2 small interfering RNA was successfully constructed and transfected into osteosarcoma cell lines. The effects of TPX2 on osteosarcoma cell proliferation were then detected by MTT assay. In addition, the expression levels of AKT signaling pathway-associated proteins were identified by western blot analysis. The expression of TPX2 was upregulated and the expression of miR-29c-3p was downregulated in osteosarcoma. High expression of TPX2 was linked to a poor prognosis. Using luciferase assay and the miRNA mimic and inhibitors, miR-29c-3p was able to target and repress TPX2, and siRNA knockdown of TPX2 resulted in the inhibition of osteosarcoma cell proliferation by affecting the AKT pathway. Overall, the study showed that miR-29c-3p could inhibit the proliferation of osteosarcoma cells via TPX2 downregulation, and that TPX2 and miR-29c-3p may serve as promising prognostic indicators.

The cell cycle‐related genes RHAMM, AURKA, TPX2, PLK1, and PLK4 are associated with the poor prognosis of breast cancer patients

Breast cancer is the third most common type of cancer diagnosed. Cell cycle is a complex but highly organized and controlled process, in which normal cells sense mitogenic growth signals that instruct them to enter and progress through their cell cycle. This process culminates in cell division generating two daughter cells with identical amounts of genetic material. Uncontrolled proliferation is one of the hallmarks of cancer. In this study, we analyzed the expression of the cell cycle-related genes receptor for hyaluronan (HA)-mediated motility (RHAMM), AURKA, TPX2, PLK1, and PLK4 and correlated them with the prognosis in a collective of 3952 breast cancer patients. A high messenger RNA expression of all studied genes correlated with a poor prognosis. Stratifying the patients according to the expression of hormonal receptors, we found that in patients with estrogen and progesterone receptor-positive and human epithelial growth factor receptor 2-negative tumors, and Luminal A and Luminal B tumors, the expression of the five analyzed genes correlates with worse survival. qPCR analysis of a panel of breast cancer cell lines representative of major molecular subtypes indicated a predominant expression in the luminal subtype. In vitro experiments showed that radiation influences the expression of the five analyzed genes both in luminal and triple-negative model cell lines. Functional analysis of MDA-MB-231 cells showed that small interfering RNA knockdown of PLK4 and TPX2 and pharmacological inhibition of PLK1 had an impact on the cell cycle and colony formation. Looking for a potential upstream regulation by microRNAs, we observed a differential expression of RHAMM, AURKA, TPX2, PLK1, and PLK4 after transfecting the MDA-MB-231 cells with three different microRNAs. Survival analysis of miR-34c-5p, miR-375, and miR-142-3p showed a different impact on the prognosis of breast cancer patients. Our study suggests that RHAMM, AURKA, TPX2, PLK1, and PLK4 can be used as potential targets for treatment or as a prognostic value in breast cancer patients.

TPX2 mediates prostate cancer epithelial-mesenchymal transition through CDK1 regulated phosphorylation of ERK/GSK3β/SNAIL pathway

Prostate cancer with high Gleason grade is prone to metastasis, which is one of the factors that seriously threaten the survival of patients, and it is also a treatment difficulty. In this study, we first revealed the potential connection between TPX2 and prostate cancer metastasis. We found that TPX2 is highly expressed in high-grade prostate cancer and is significantly related to poor prognosis. Depletion of TPX2 can significantly inhibit cell activity and migration, and in vivo experiments show that knockdown of TPX2 can significantly inhibit tumor growth. In terms of mechanism, we found that knocking down TPX2 can inhibit the expression of CDK1, repress the phosphorylation of ERK/GSK3β/SNAIL signaling pathway, and thereby inhibit tumor epithelial-mesenchymal transition. Subsequently, we found that after rescuing TPX2, all related proteins and phenotype changes were restored, and this effect can be inhibited by CDK1 inhibitor, RO-3306. Our findings suggest the potential of TPX2 as an important target in anti-tumor metastasis therapy, which is conducive to precision medicine for prostate cancer.

CircPOSTN/miR-361-5p/TPX2 axis regulates cell growth, apoptosis and aerobic glycolysis in glioma cells

BackgroundGlioma is the most primary central nervous system tumor in adults. The 5 year survival rate for glioma patients remains poor, although treatment strategies had improved in the past few decades. The cumulative studies have shown that circular RNA (circRNA) is associated with glioma process, so the purpose of this study is to clarify the function of circPOSTN in glioma.MethodsThe expression levels of circPOSTN, miR-361-5p, and targeting protein for Xenopus kinesin-like protein 2 (TPX2) were assessed with real-time quantitative polymerase chain reaction (RT-qPCR). The 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-2H-tetrazol-3-ium bromide (MTT) and flow cytometry assays were executed to examine proliferation and apoptosis of glioma cells, respectively. Western blot was applied to assess protein expression. The glucose metabolism of glioma cells was analyzed by testing the glucose consumption, lactate production, ATP level, reactive oxygen species (ROS) accumulation and performing Seahorse XF assay. The interaction relationship between miR-361-5p and circPOSTN or TPX2 was analyzed by bioinformatics database and dual-luciferase reporter assay. The influences of circPOSTN silencing in vivo were observed by a xenograft experiment.ResultsCircPOSTN was overexpressed in glioma tissues and cells. Absence of circPOSTN in glioma cells promoted apoptosis while impeded proliferation and aerobic glycolysis, which were mitigated by silencing miR-361-5p. What’s more, loss-of-functional experiment suggested that knockdown of TPX2 repressed proliferation and aerobic glycolysis, while induced apoptosis in glioma cells. In addition, circPOSTN targetedly regulated TPX2 expression in glioma cells via sponging miR-361-5p. In vivo study revealed that deficiency of circPOSTN restrained tumor growth.ConclusionMechanistically, circPOSTN regulated cell growth, apoptosis, and aerobic glycolysis in glioma through miR-361-5p/TPX2 axis.

The critical role of dysregulated Hh-FOXM1-TPX2 signaling in human hepatocellular carcinoma cell proliferation

BackgroundAberrant activation of the Hedgehog (Hh) signaling pathway is frequently observed in hepatocellular carcinoma (HCC), nevertheless, the precise molecular mechanism remains unclear. Forkhead box M1 (FOXM1), a target of the Hh pathway, is a key oncofetal transcription factor and a master cell cycle regulator. Targeting protein for Xenopus kinesin-like protein 2 (TPX2) is an oncogene critical for mitosis. However, how these molecular events affect HCC progression remains unclear.MethodsRealtime PCR, immunohistochemistry, western blotting, and analyses of datasets TCGA and Gene Expression Omnibus (GEO) were conducted to assess the expression of TPX2 and FOXM1 at the mRNA and protein levels in HCC samples or HCC cells. Expression and knockdown of TPX2 and FOXM1 were performed to assess their role in regulating HCC cell proliferation in vitro and in vivo. Dual luciferase report assay and chromosome immunoprecipitation (ChIP) were investigated to seek the FOXM1 binding sites in the promoter of TPX2.ResultsSpecific antagonists (cyclopamine and GANT61) of the Hh pathway down-regulated TPX2, whereas activation of Hh signaling stimulated TPX2 expression. Furthermore, TPX2 over-expression accelerated HCC cell proliferation when upstream events of Hh signaling were inhibited, and TPX2 knockdown significantly alleviated Sonic Hh ligand (Shh)-induced HCC cell proliferation. Reporter assays and ChIP showed that FOXM1 bound to the TPX2 promoter, confirming that TPX2 is a direct downstream target of FOXM1. Xenograft model further verified the cell function and expression regulation of TPX2 and FOXM1 in vivo. Furthermore, FOXM1 regulated TPX2 activity to drive HCC proliferation. Immunohistochemical (IHC) analysis indicated that FOXM1 and TPX2 were highly-expressed in HCC samples and cohort study revealed that FOXM1 and TPX2 may act as negative predictors for the prognosis of patients with HCC.ConclusionsTPX2 acts as a novel downstream target and effector of the Hh pathway, and Hh signaling contributes to HCC proliferation via regulating the FOXM1-TPX2 cascade, suggesting that this signaling axis may be a novel therapeutic target for HCC.Graphical abstract

TPX2 silencing exerts anti‑tumor effects on hepatocellular carcinoma by regulating the PI3K/AKT signaling pathway.

Hepatocellular carcinoma (HCC) is one of the primary causes of cancer-associated deaths worldwide. Current treatment methods include surgical resection, chemotherapy and radiotherapy; however the curative rate remains low, thus novel treatments are required. The aim of the present study was to investigate the role of targeting protein for Xenopus kinesin-like protein 2 (TPX2) in the growth of HCC and its underlying molecular mechanism. Immunohistochemistry staining, reverse transcription-quantitative (RT-q)PCR and western blotting were used to detect the expression of TPX2 mRNA and protein in liver cancer tissue samples, adjacent normal liver tissue samples, and the HCC cell lines Huh7, Hep3B, PLC/PRF/5 and MHCC97-H. The recombinant plasmid pMagic4.1-shRNA-TPX2 was constructed and transfected into Huh7 and Hep3B HCC cells to silence TPX2 expression. The proliferation, apoptosis, migration and invasion of Huh7 cells and Hep3B cells were evaluated before and after TPX2 silencing. The mRNA and protein expression levels of multiple signaling pathway-associated genes were detected by RT-qPCR and western blotting. The expression levels of TPX2 mRNA and protein were significantly higher in HCC tissue samples compared with adjacent normal liver tissue sample. TPX2 mRNA and protein expression levels were detected in the different HCC cell lines. The recombinant plasmid pMagic4.1-shRNA-TPX2 was successfully transfected into Huh7 and Hep3B cells, resulting in TPX2 silencing. TPX2 knockdown significantly reduced cell proliferation, cell migration and cell invasion of Huh7 and Hep3B cells, whilst also increasing the rate of apoptosis in these cells. Following TPX2 silencing, the expression levels of PI3K, phospho-AKT, Bcl-2, c-Myc and Cyclin D1 were significantly decreased, whereas the expression levels of P21 and P27 were significantly increased. In conclusion, TPX2 may suppress the growth of HCC by regulating the PI3K/AKT signaling pathway and thus, TPX2 may be a potential target for the treatment of liver cancer.

Glucolipotoxicity Alters Insulin Secretion via Epigenetic Changes in Human Islets.

Type 2 diabetes (T2D) is characterized by insufficient insulin secretion and elevated glucose levels, often in combination with high levels of circulating fatty acids. Long-term exposure to high levels of glucose or fatty acids impair insulin secretion in pancreatic islets, which could partly be due to epigenetic alterations. We studied the effects of high concentrations of glucose and palmitate combined for 48 h (glucolipotoxicity) on the transcriptome, the epigenome, and cell function in human islets. Glucolipotoxicity impaired insulin secretion, increased apoptosis, and significantly (false discovery rate <5%) altered the expression of 1,855 genes, including 35 genes previously implicated in T2D by genome-wide association studies (e.g., TCF7L2 and CDKN2B). Additionally, metabolic pathways were enriched for downregulated genes. Of the differentially expressed genes, 1,469 also exhibited altered DNA methylation (e.g., CDK1, FICD, TPX2, and TYMS). A luciferase assay showed that increased methylation of CDK1 directly reduces its transcription in pancreatic β-cells, supporting the idea that DNA methylation underlies altered expression after glucolipotoxicity. Follow-up experiments in clonal β-cells showed that knockdown of FICD and TPX2 alters insulin secretion. Together, our novel data demonstrate that glucolipotoxicity changes the epigenome in human islets, thereby altering gene expression and possibly exacerbating the secretory defect in T2D.

Targeting TPX2 suppresses proliferation and promotes apoptosis via repression of the PI3k/AKT/P21 signaling pathway and activation of p53 pathway in breast cancer

Targeting protein for Xenopus kinesin-like protein 2 (TPX2) is a microtubule-associated protein required for mitosis and spindle assembly. Previous studies showed that TPX2 is overexpressed in various human cancers and promotes cancer progression. In this study, the differentially expressed genes including TPX2 were screened in GEO database for gene expression microarray of breast cancer. The TPX2 expression level was significantly increased in breast cancer cells and the breast malignant tissues compared with those controls. In vitro experiment further confirmed that knockdown of TPX2 by small hairpin RNA inhibited breast cancer cell proliferatio, migration, and induced cell apoptosis. TPX2 silencing decreased the expression of PI3K and extent of AKT phosphorylation, as well as increased expression of p53 and p21. Taken together, our findings indicate that TPX2 silencing negatively regulates the PI3K/AKT and activates p53 signaling pathway by which breast cancer cells proliferation were inhibited whereas cellulars apoptosis were accelerated, suggesting that TPX2 may be a potential target for anticancer therapy in breast cancer.

TPX2 promotes cell proliferation and migration via PLK1 in OC.

Targeting protein for Xenopus kinesin-like protein 2 (TPX2) is a microtubule-associated proteinrequired for mitosis and spindle assembly. It has been revealed that TPX2 is overexpressedin various human cancers and promotes cancer progression. The expression of TPX2 was examined in ovarian cancer (OC) tissues and by Western blotting, quantitative real-time reverse transcription PCR (qRT-PCR) and immunohistochemistry. The effects of TPX2 on proliferation and migration of two OC cell lines SKOV3and RMG1 were analyzed using the methylthiazol tetrazolium (MTT) assay, flow cytometry and transwell assay. The mechanisms underlying the effects of TPX2 on OC cells were explored by qRT-PCR and Western blot. In this study, we found that TPX2 was upregulated in OC tissues. We observed knockdown of TPX2 inhibited the expression of Polo-like kinase 1 (PLK1), which has an important role in the regulation of M phase of the cell cycle, and the activity of Cdc2, induced cell arrested at the G2/M phase and decreased proliferation. Moreover, our data revealed that the levels of PLK1, β-catenin, MMP7 and MMP9 were inhibited following TPX2 knockdown, leading to decrease of cell migration. Finally, we showed that the restoration of PLK1 expression attenuated the anti-proliferation and anti-migration effects of TPX2 knockdown in OC cells. TPX2 promotes the proliferation and migration of human OC cells by regulating PLK1 expression.

Targeting protein for Xenopus kinesin-like protein 2 knockdown enhances radiation sensitivity of human lung squamous carcinoma cell.

The targeting protein for Xenopus kinesin-like protein 2 (TPX2) has been demonstrated to be associated with the tumourigenesis of many cancers. In the present study, we investigated the role and preliminary mechanism of TPX2 in the resistance of lung squamous carcinoma to radiation therapy. The results showed that SK-MES-1R and NCI-H226R cells were more resistant to X-ray irradiation than the parental cells (SK-MES-1 and NCI-H226). Moreover, TPX2 was upregulated in the radioresistant cells compared with the parental cells. TPX2 knockdown significantly decreased TPX2 expression in SK-MES-1 cells, while TPX2 overexpression increased TPX2 expression in NCI-H226 cells compared with the corresponding control cells. TPX2 knockdown enhanced the radiosensitivity of SK-MES-1 and promoted cell apoptosis following exposure to irradiation, whereas TPX2 overexpression decreased the radiosensitivity of NCI-H226 and inhibited cell apoptosis. In in vivo studies, the combination of TPX2 knockdown and irradiation significantly inhibited tumour growth, decreased tumour weight, downregulated TPX2 expression in tumour tissue and induced cell apoptosis in nude mice, while TPX2 overexpression exerted an opposite effect. Our results indicated that TPX2 was correlated with cell radioresistance and it might be served as a therapeutic target to enhance cell radiosensitivity in the radiation therapy of lung squamous carcinoma.

TPX2 promotes glioma cell proliferation and invasion via activation of the AKT signaling pathway.

Glioblastoma multiforme (GBM) is the most common and most malignant type of primary adult brain cancer. The most common phenotype associated with GBM is cellular invasion; however, the molecular mechanisms governing this process are poorly understood. Targeting protein for Xenopus kinesin-like protein 2 (TPX2) is a nuclear protein with roles in cellular proliferation and mitotic spindle assembly. TPX2 is overexpressed in various malignancies, including human malignant astrocytoma. Despite this finding, the exact role of TPX2 in human glioma is not well defined. The present study reports the elevated expression of TPX2 in a number of glioma cell lines. TPX2 overexpression promoted cellular proliferation, decreased the percentage of cells in G0/G1 phase, and increased invasion of both U251 and U87 cells. Overexpression of TPX2 also significantly enhanced the phosphorylation of AKT, decreased the expression of p21, and increased the expression of cyclin D1 and matrix metallopeptidase (MMP)-9. In both U251 and U87 cells, knockdown of TPX2 resulted in phenotypes that are in direct contrast to those observed following TPX2 overexpression. Specifically, TPX2 knockdown inhibited cell proliferation, increased the percentage of cells in G0/G1 phase, inhibited invasion, decreased AKT phosphorylation, decreased the expression of MMP-9 and cyclin D1, and increased p21 expression. The AKT inhibitor IV in large part phenocopied the effect of TPX2 knockdown. The present data suggest that TPX2 promotes glioma cell proliferation and invasion via AKT signaling.

The AURKA/TPX2 axis drives colon tumorigenesis cooperatively with MYC

The MYC oncogene has long been established as a central driver in many types of human cancers including colorectal cancer. However, the realization of MYC-targeting therapies remains elusive; as a result, synthetic lethal therapeutic approaches are alternatively being explored. A synthetic lethal therapeutic approach aims to kill MYC-driven tumors by targeting a certain co-regulator on the MYC pathway. We analyzed copy number and expression profiles from 130 colorectal cancer tumors together with publicly available datasets to identify co-regulators on the MYC pathway. Candidates were functionally tested by in vitro assays using colorectal cancer and normal fibroblast cell lines. Additionally, survival analyses were carried out on another 159 colorectal cancer patients and public datasets. Our in silico screening identified two MYC co-regulator candidates, AURKA and TPX2, which are interacting mitotic regulators located on chromosome 20q. We found the two candidates showed frequent co-amplification with the MYC locus while expression levels of MYC and the two genes were positively correlated with those of MYC downstream target genes across multiple cancer types. In vitro, the aberrant expression of MYC, AURKA and TPX2 resulted in more aggressive anchorage-independent growth in normal fibroblast cells. Furthermore, knockdown of AURKA or TPX2, or treatment with an AURKA-specific inhibitor effectively suppressed the proliferation of MYC-expressing colorectal cancer cells. Additionally, combined high expression of MYC, AURKA and TPX2 proved to be a poor prognostic indicator of colorectal cancer patient survival. Through bioinformatic analyses and experiments, we proposed TPX2 and AURKA as novel co-regulators on the MYC pathway. Inhibiting the AURKA/TPX2 axis would be a novel synthetic lethal therapeutic approach for MYC-driven cancers.

TPX2 as a novel prognostic biomarker for hepatocellular carcinoma.

Targeting protein for Xenopus kinesin-like protein 2 (TPX2) is a microtubule-associated protein that impacts spindle assembly in human cells. Several studies have shown that the overexpression of TPX2 is correlated with multiple tumor types. However, the role of TPX2 in hepatocellular carcinoma (HCC) remains undetermined. TPX2 expression was detected by quantitative reverse transcription polymerase chain reaction and immunoblotting in six cell lines and 130 pairs of HCC and adjacent non-cancerous liver tissues. Matrix metalloproteinase (MMP)2 and MMP9 expression was detected by immunohistochemistry to evaluate their correlations with TXP2. TPX2 siRNA was used to knock down TPX2 expression, and cell migration and invasion were determined. Moreover, clinical significance of TPX2 in HCC was analyzed. TPX2 expression was found to be obviously higher in HCC tissues than that in non-tumor tissues. Elevated TPX2 expression was observed in HCC cell lines as compared with that in a non-transformed hepatic cell line. Clinical analysis indicated that TPX2 expression in the HCC tissues was evidently correlated with the tumor-node-metastasis stage, tumor number and tumor differentiation. TPX2 is a novel prognostic marker for predicting 5-year overall survival and disease-free survival of HCC patients. TPX2 expression was positively correlated with MMP2 and MMP9. In vitro studies found that TPX2 knockdown prominently reduced cell invasion and migration and decreased phosphorylated AKT, MMP2 and MMP9 expression in MHCC-97H cells. Overexpression of TPX2 was associated with clinicopathological characteristics and poor patient outcomes. TPX2 may serve as a novel prognostic marker for HCC.