The aim of the study was to detect PPA1 expression in various tumors and to investigate the relationship between PPA1 expression and clinicopathological parameters to further analyze its clinical significance. Immunohistochemical staining detected PPA1 expression in 305 noncancerous tissues and 675 tumor tissues, which included 12 different tumor types. QPCR and western blot examined PPA1 expression in tumor‐derived cell lines including those derived from liver, breast, lung, and ovarian cancers. Cell proliferation and apoptosis assays were used to investigate PPA1‐regulated cell growth in tumor cells. Finally, a bioinformatics analysis was used to verify the role of PPA1 in carcinogenesis. Among the 12 types of tumors, PPA1 expression was significantly higher in lung and ovarian cancers (P < 0.001). In lung cancer, PPA1 expression was associated with tumor size, patients’ age, and smoking status, whereas in ovarian cancer, PPA1 expression was associated with pathological grade (P < 0.05). Moreover, we found that PPA1 expression was up‐regulated in lung and ovarian cancer cell lines compared with nontumor cells. In addition, suppression of PPA1 expression by RNA interference in lung and ovarian cancer cells showed increased cell apoptosis and decreased cell proliferation, which was mediated by TP53 and p21 signaling. Notably, a bioinformatics analysis was used to verify the function of PPA1 in the development and progression of tumors. PPA1 expression is significantly higher in many tumors, especially those of lung and ovarian origin, which suggests that PPA1 plays an important role in carcinogenesis and in the development of some tumors.

To date, only some cancer patients can benefit from chemotherapy and targeted therapy. Drug resistance continues to be a major and challenging problem facing current cancer research. Rapidly accumulated patient-derived clinical transcriptomic data with cancer drug response bring opportunities for exploring molecular determinants of drug response, but meanwhile pose challenges for data management, integration, and reuse. Here we present the Cancer Treatment Response gene signature DataBase (CTR-DB, http://ctrdb.ncpsb.org.cn/), a unique database for basic and clinical researchers to access, integrate, and reuse clinical transcriptomes with cancer drug response. CTR-DB has collected and uniformly reprocessed 83 patient-derived pre-treatment transcriptomic source datasets with manually curated cancer drug response information, involving 28 histological cancer types, 123 drugs, and 5139 patient samples. These data are browsable, searchable, and downloadable. Moreover, CTR-DB supports single-dataset exploration (including differential gene expression, receiver operating characteristic curve, functional enrichment, sensitizing drug search, and tumor microenvironment analyses), and multiple-dataset combination and comparison, as well as biomarker validation function, which provide insights into the drug resistance mechanism, predictive biomarker discovery and validation, drug combination, and resistance mechanism heterogeneity.

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Inorganic pyrophosphatase (PPA1) promotes tumor progression in several tumor types. However, the underlying mechanism remains elusive. Here, we disclosed that PPA1 expression is markedly upregulated in lung carcinoma tissue versus normal lung tissue. We also found that the non-small cell lung cancer (NSCLC) cell lines show increased PPA1 expression levels versus normal lung cell line control. Moreover, the knockdown of PPA1 promotes cell apoptosis and inhibits cell proliferation. Whereas, the ectopic expression of PPA1 reduces cell apoptosis and enhances cell proliferation. Most interestingly, the expression of mutant PPA1 (D117A) significantly abolishes PPA1-mediated effect on cell apoptosis and proliferation. The underlying mechanism demonstrated that TP53 expression deficiency or JNK inhibitor treatment could abolish PPA1-mediated NSCLC progression. In summary, the aforementioned findings in this study suggest a new pathway the PPA1 mediates NSCLC progression either via TP53 or JNK. Most important, the pyrophosphatase activity is indispensible for PPA1-mediated NSCLC progression. This may provide a promising target for NSCLC therapy.