This study provides insight into the architecture of common genetic variation contributing to CRC etiology and improves risk prediction for individualized screening.
Human mitochondrial pyrroline-5-carboxylate reductase (PYCR) is a house-keeping enzyme that catalyzes the reduction of Δ1-pyrroline-5-carboxylate to proline. This enzymatic cycle plays pivotal roles in amino acid metabolism, intracellular redox potential and mitochondrial integrity. Here, we hypothesize that PYCR1 might be a novel prognostic biomarker and therapeutic target for breast cancer. In this study, breast cancer tissue samples were obtained from Zhejiang University (ZJU set). Immunohistochemistry analysis was performed to detect the protein level of PYCR1, and Kaplan-Meier and Cox proportional analyses were employed in this outcome study. The prognostic significance and performance of PYCR1 mRNA were validated on 13 worldwide independent microarray data sets, composed of 2500 assessable breast cancer cases. Our findings revealed that both PYCR1 mRNA and protein expression were significantly associated with tumor size, grade and invasive molecular subtypes of breast cancers. Independent and pooled analyses verified that higher PYCR1 mRNA levels were significantly associated with poor survival of breast cancer patients, regardless of estrogen receptor (ER) status. For in vitro studies, inhibition of PYCR1 by small-hairpin RNA significantly reduced the growth and invasion capabilities of the cells, while enhancing the cytotoxicity of doxorubicin in breast cancer cell lines MCF-7 (ER positive) and MDA-MB-231 (ER negative). Further population study also validated that chemotherapy significantly improved survival in early-stage breast cancer patients with low PYCR1 expression levels. Therefore, PYCR1 might serve as a prognostic biomaker for either ER-positive or ER-negative breast cancer subtypes and can also be a potential target for breast cancer therapy.
Malignant gliomas are difficult to treat in clinical practice. This study was aimed to investigate the preclinical efficacy of CRLX101, an investigational nanoparticle-drug conjugate developed by conjugating camptothecin (CPT) with cyclodextrin-polyethylene glycol, against gliomas. CPT fluorescence was detected across tight-junction barriers and in mouse plasma and brain. Following CRLX101 treatment, CPT was distributed in the cytoplasm of human U87 MG glioma cells. U87 MG cell viability was decreased by CRLX101 and CPT. Moreover, CRLX101 induced less cytotoxicity to human astrocytes compared to CPT. Exposure of U87 MG cells to CRLX101 induced G2/M cell cycle arrest and apoptosis. Administration of CRLX101 induced apoptosis in mice brain tumor tissues and prolonged the survival rate of mice. In addition, CRLX101 inhibited hypoxia and angiogenesis by suppressing the expression of carbonic anhydrase IX, vascular endothelial growth factor, and CD31 in tumor sections. Taken together, this preclinical study showed that CRLX101 possesses antitumor abilities by inducing cell cycle arrest and apoptosis in glioma cells and inhibiting tumor angiogenesis, thereby prolonging the lifespan of mice bearing intracranial gliomas. These data support further research of CRLX101 in patients with brain tumors.
Abnormal spindle-like microcephaly-associated (ASPM) protein is essential for mitotic spindle function during cell replication. The present study aimed to evaluate the hypothesis that ASPM serves a critical role in cancer invasiveness and may act as a prognostic biomarker in bladder cancer. In total, 6 independent worldwide bladder cancer microarray mRNA expression datasets (n=1,355) with clinical and follow-up annotations were collected from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases. Reverse transcription-quantitative polymerase chain reaction analysis revealed that ASPM mRNA expression was higher in bladder cancer tissue compared with adjacent normal bladder mucosae in 10 paired human tissue samples (P=0.004). ASPM overexpression in human bladder cancer samples was consistent with the mRNA expression datasets from GEO and TCGA. Bioinformatics analysis indicated that ASPM mRNA expression was significantly associated with grade and tumor node metastasis (TNM) stage in bladder cancer, based on pooled GEO and TCGA datasets (P<0.05). Stratification analysis indicated that the clinical significance of ASPM was particularly pronounced in low-grade or papillary subtypes of bladder cancer. Individual Cox and pooled Kaplan-Meier analyses suggested that ASPM expression was significantly directly correlated with poor overall (OS) and progression-free survival (PFS) in bladder cancer. Multivariate and stratification analyses demonstrated that the prognostic significance of ASPM was evident in low-grade or papillary bladder cancers, yet not in high-grade or non-papillary subgroups. Increased expression of ASPM was associated with poor OS in muscle-invasive bladder cancer and with poor PFS in non-muscle-invasive bladder cancer (P<0.05). Bioinformatics analysis identified the top 11 ASPM-related genes on STRING-DB.org. The expression of the majority of these genes was associated with poor outcomes of bladder cancer with statistical significance. Gene set enrichment analysis indicated that the high expression of ASPM could enrich gene signatures involved in mitosis, differentiation and metastasis in bladder cancer. Further analysis of TCGA datasets indicated that increased ASPM expression was significantly associated with higher Gleason score, T stage, N stage and poor clinical outcome in prostate cancer. It was also significantly associated with late TNM stage and poor PFS in renal cell carcinoma. In summary, ASPM may serve as a novel prognostic biomarker for low-grade or papillary bladder cancer.
Mitochondrial serine hydroxylmethyltransferase 2 (SHMT2) is a key enzyme in the serine/glycine synthesis pathway. SHMT2 has been implicated as a critical component for tumor cell survival. The aim of the present study was to evaluate the prognostic value and efficiency of SHMT2 as a biomarker in patients with breast cancer. Individual and pooled survival analyses were performed on five independent breast cancer microarray datasets. Gene signatures enriched by SHMT2 were also analyzed in these datasets. SHMT2 protein expression was detected using immunohistochemistry (IHC) assay in 128 breast cancer cases. Gene set enrichment analysis revealed that SHMT2 was significantly associated with gene signatures of mitochondrial module, cancer invasion, metastasis and poor survival among breast cancer patients (p<0.05). The clinical relevance of SHMT2 was validated on IHC data. The mitochondrial localization of SHMT2 protein was visualized on IHC staining. Independent and pooled analysis confirmed that SHMT2 expression was associated with breast cancer tumor aggressiveness (TNM staging and Elson grade) in a dose-dependent manner (p<0.05). The prognostic performance of SHMT2 mRNA was comparable to other gene signatures and proved superior to TNM staging. Further analysis results indicated that SHMT2 had better prognostic value for estrogen receptor (ER)-negative breast cancer patients, compared to ER-positive patients. In cases involving stage IIb breast cancer, chemotherapy significantly extended survival time among patients with high SHMT2 expression. These results indicate that SHMT2 may be a valuable prognostic biomarker in ER-negative breast cancer cases. Furthermore, SHMT2 may be a potential target for breast cancer treatment and drug discovery.
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