Clinical value of Xenopus kinesin-like protein 2 as a prognostic marker in patients with digestive system cancers: a systematic review and meta-analysis

TPX2 expression as a negative predictor of gemcitabine efficacy in pancreatic cancer

BACKGROUND

Targeting protein for Xenopus kinesin-like protein 2 (TPX2) overexpression in human tumours is associated with increased malignancy. Its effect on gemcitabine resistance in pancreatic ductal adenocarcinoma (PDAC) has not been studied yet.

METHODS

The prognostic impact of TPX2 expression was examined in the tumour tissue of 139 patients with advanced PDAC (aPDAC) treated within the AIO-PK0104 trial or translational trials and of 400 resected PDAC (rPDAC) patients. The findings were validated using RNAseq data of 149 resected PDAC patients.

RESULTS

In the aPDAC cohorts, 13.7% of all samples showed high TPX2 expression, conferring significantly shorter progression-free survival (PFS, HR 5.25, P < 0.001) and overall survival times (OS, HR 4.36, P < 0.001) restricted to gemcitabine-based treated patients (n = 99). In the rPDAC cohort, 14.5% of all samples showed high TPX2 expression, conferring significantly shorter disease-free survival times (DFS, HR 2.56, P < 0.001) and OS times (HR 1.56, P = 0.04) restricted to patients treated with adjuvant gemcitabine. RNAseq data from the validation cohort confirmed the findings.

CONCLUSIONS

High TPX2 expression may serve as a negative predictor of gemcitabine-based palliative and adjuvant chemotherapy in PDAC and could be used to inform clinical therapy decisions.

CLINICAL TRIAL REGISTRY

The clinical trial registry identifier is NCT00440167.

Phase separation of TPX2 enhances and spatially coordinates microtubule nucleation

Phase separation of substrates and effectors is proposed to enhance biological reaction rates and efficiency. Targeting protein for Xklp2 (TPX2) is an effector of branching microtubule nucleation in spindles and functions with the substrate tubulin by an unknown mechanism. Here we show that TPX2 phase separates into a co-condensate with tubulin, which mediates microtubule nucleation in vitro and in isolated cytosol. TPX2-tubulin co-condensation preferentially occurs on pre-existing microtubules, the site of branching microtubule nucleation, at the endogenous and physiologically relevant concentration of TPX2. Truncation and chimera versions of TPX2 suggest that TPX2-tubulin co-condensation enhances the efficiency of TPX2-mediated branching microtubule nucleation. Finally, the known inhibitor of TPX2, the importin-α/β heterodimer, regulates TPX2 condensation in vitro and, consequently, branching microtubule nucleation activity in isolated cytosol. Our study demonstrates how regulated phase separation can simultaneously enhance reaction efficiency and spatially coordinate microtubule nucleation, which may facilitate rapid and accurate spindle formation.

Comprehensive analysis of TPX2-related ceRNA network as prognostic biomarkers in lung adenocarcinoma

Background and aim: Competing endogenous RNA (ceRNA) is believed to play vital roles in tumorigenesis. The goal of this study was to screen prognostic biomarkers in lung adenocarcinoma (LUAD). Methods: Common differentially expressed genes (DEGs) were collected from Gene Expression Omnibus (GEO) databases and The Cancer Genome Atlas databases (TCGA) using GEO2R and "limma" package in R, respectively. Overlapping DEGs were conducted using enrichment of functions and protein-protein interaction (PPI) network to discover significant candidate genes. By using a comprehensive analysis, we constructed an mRNA mediated ceRNA network. Survival rates were used Kaplan-Meier analysis. Statistical analysis was used to further identify the prognosis of studied genes. Results: Integrated analysis of GSE32863 and TCGA databases, a total of 886 overlapping DEGs, including 279 up-regulated and 607 down-regulated genes were identified. Considering the highest term of candidate genes in PPI, we identified TPX2, which was enriched in cell division signaling pathway. Besides, 35 differentially expressed miRNAs (DEmiRNAs) were predicted to target TPX2 and only 7 DEmiRNAs were identified to be prognostic biomarkers in LUAD. Then, 30 differentially expressed lncRNAs (DElncRNAs) were predicted to bind these 7 DEmiRNAs. Finally, we found that 7 DElncRNAs were correlated with the overall survival (all p <0.05). Furthermore, we identified elevated TPX2 was strongly correlated with the worse survival rate among 458 samples. Univariate and multivariate cox analysis showed TPX2 may act as an independent factor for prognosis in LUAD (p <0.05). Then pathway enrichment results suggested that TPX2 may facilitate tumorigenesis by participating in several cancer-related signaling pathways in LUAD, especially in Notch signal pathway. Conclusions: TPX2-related lncRNAs and miRNAs are related to the survival of LUAD. 7 lncRNAs, 7 miRNAs and TPX2 may serve as prognostic biomarkers in LUAD.

Prognostic role of targeting protein for Xklp2 in solid tumors: A PRISMA-compliant systematic review and meta-analysis

BACKGROUND

The prognostic role of targeting protein for Xklp2 (TPX2) in solid tumors has been investigated in several researches, but the results remain controversial. Here we present a meta-analysis to systematically review the association between TPX2 expression levels and prognosis of human solid tumors.

METHODS

Studies published until December 2017 were searched in PubMed, Web of Science, and EBSCO, 13 studies (2134 patients) were collected for analysis. Odds ratios (ORs) for overall survival (OS) and disease-free survival (DFS) from individual studies were calculated by the application of Mantel-Haenszel random effect model. Pooled ORs were estimated by Z test. Publication bias and interstudy heterogeneity analyses were also performed.

RESULTS

TPX2 overexpression was associated with poor OS at 3 and 5 years [OR = 4.63, 95% confidence interval (CI): 3.27-6.56, P < .00001; OR = 4.05, 95% CI: 2.32-7.07, P < .00001, respectively] of solid tumors. Similar results were observed with DFS at 3 and 5 years (OR = 3.35, 95% CI: 1.83-6.14, P < .0001; OR = 2.94, 95% CI: 1.74-4.98, P < .0001, respectively). Subgroup analysis revealed that increased TPX2 expression was related to worse prognosis of gastric cancer and hepatocellular cancer, while irrelevant to esophageal squamous cell cancer at 5-year survival rate.

CONCLUSIONS

Overexpression of TPX2 is related to poor survival rate in most solid tumors, which indicates that the expression level of TPX2 is a significant prognostic parameter and potential therapeutic target in various solid tumors.