ABSTRACT
The epidermal growth factor receptor is the only available tyrosine kinase molecular target for treating oral cancer. To improve the prognosis of tongue squamous cell carcinoma (TSCC) patients, a novel molecular target for tyrosine kinases is thus needed. We examined the expression of interleukin-2-inducible T-cell kinase (ITK) using immunohistochemistry, and the biological function of ITK was investigated using biochemical, phosphoproteomic, and metabolomic analyses. We found that ITK is overexpressed in TSCC patients with poor outcomes. The proliferation of oral cancer cell lines expressing ITK via transfection exhibited significant increases in three-dimensional culture assays and murine inoculation models with athymic male nude mice as compared with mock control cells. Suppressing the kinase activity using chemical inhibitors significantly reduced the increase in cell growth induced by ITK expression. Phosphoproteomic analyses revealed that ITK expression triggered phosphorylation of a novel tyrosine residue in trifunctional purine biosynthetic protein adenosine-3, an enzyme in the purine biosynthesis pathway. A significant increase in de novo biosynthesis of purines was observed in cells expressing ITK, which was abolished by the ITK inhibitor. ITK thus represents a potentially useful target for treating TSCC through modulation of purine biosynthesis.
ABSTRACT
AIM: Although several clinical trials demonstrated the benefits of platinum-combination adjuvant chemotherapy for stage II-IIIA lung adenocarcinoma, predictive biomarkers for the efficacy of such therapy have not yet been identified. We evaluated protein overexpression of actinin-4 as a predictive biomarker of the efficacy of adjuvant chemotherapy in resected lung adenocarcinoma. MATERIALS & METHODS: We measured actinin-4 protein levels in patients with completely resected stage II-IIIA lung adenocarcinoma using immunohistochemistry and then retrospectively compared survival between adjuvant chemotherapy and observation groups. RESULTS: A total of 148 eligible patients were classified into actinin-4 positive or negative cases by immunohistochemistry. In the former, patients with adjuvant chemotherapy survived significantly longer than those with observation (hazard ratio [HR]: 0.307; p = 0.028). But, no significant survival benefit was noted with adjuvant chemotherapy (HR: 0.926; p = 0.876) in the latter. CONCLUSION: This marker could predict the efficacy of adjuvant chemotherapy for resected lung adenocarcinoma patients.
Subject(s)
Actinin/metabolism , Adenocarcinoma of Lung/drug therapy , Biomarkers, Tumor/metabolism , Chemotherapy, Adjuvant , Actinin/genetics , Adenocarcinoma of Lung/mortality , Adenocarcinoma of Lung/pathology , Adenocarcinoma of Lung/surgery , Aged , Aged, 80 and over , Antineoplastic Agents/therapeutic use , Area Under Curve , Biomarkers, Tumor/genetics , Female , Humans , Kaplan-Meier Estimate , Male , Middle Aged , Neoplasm Staging , Prognosis , Proportional Hazards Models , ROC Curve , Retrospective StudiesABSTRACT
Although several clinical trials have demonstrated the benefits of platinum-combined adjuvant chemotherapy for resected non-small cell lung cancer (NSCLC), predictive biomarkers for the efficacy of such therapy have not yet been identified. Selection of patients with high metastatic ability in the early stage of non-small cell lung cancer (NSCLC) has the potential to predict clinical benefit of adjuvant chemotherapy (ADJ).In order to develop a predictive biomarker for efficacy of ADJ, we reanalyzed patient data using a public database enrolled by JBR.10, which was a clinical trial to probe the clinical benefits of ADJ in stage-IB/II patients with NSCLC. The patients who were enrolled by JBR.10 were classified into 2 subgroups according to expression of the ACTN4 transcript: ACTN4 positive (ACTN4 (+)) and ACTN4 negative (ACTN4 (-)). In the ACTN4 (+) group, overall survival (OS) was significantly higher in the ADJ subgroup compared with the observation subgroup (OBS), indicating a significant survival benefit of ADJ. However, no difference in OS was found between ADJ and OBS groups in ACTN4 (-). Although ACTN4 expression level did not correlate with the chemosensitivity of cancer cell lines for cytotoxic drugs, the metastatic potential of A549 lung adenocarcinoma cells was significantly reduced by ACTN4 shRNA in in vitro assays and in an animal transplantation model. The clinical and preclinical data suggested that ACTN4 is a potential predictive biomarker for efficacy of ADJ in stage-IB/II patients with NSCLC, by reflecting the metastatic potential of tumor cells.
