Small-cell lung cancer, a highly malignant form of lung cancer, often responds to first-line treatments but relapses in most cases with resistance to further treatments. We tested zinc oxide (ZnO) nanoparticles against small-cell lung cancer and other cancer cell lines, in light of reported anticancer effects in vitro. Because of a strong safety record, ZnO nanoparticles are frequently used in biomedical research, including in cellular imaging and drug delivery, and have been used for many years in several commercial products such as skin care agents. Strikingly, ZnO nanoparticles were genotoxic against small-cell lung cancer cells, resulting in low viability, even in cells orthotopically grafted onto mouse models. However, the nanoparticles were less cytotoxic against normal lung-derived cells and did not elicit observable adverse effects after intravenous administration. ZnO nanoparticles were also found to induce highly reactive oxygen species and DNA leakage from nuclei. This study is the first comprehensive evaluation of the anticancer effects of ZnO nanoparticles in vitro and in vivo and highlights new therapeutic opportunities against small-cell lung cancer.

BackgroundProtein tyrosine kinase 2 (PTK2) expression has been reported in various types of human epithelial cancers including lung cancer; however, the role of PTK2 in epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) has not been elucidated. We previously reported that pemetrexed-resistant NSCLC cell line PC-9/PEM also acquired EGFR-TKI resistance with constitutive Akt activation, but we could not find a therapeutic target.MethodsCell viability in EGFR-mutant NSCLC cell lines was measured by the WST-8 assay. Phosphorylation antibody array assay for receptor tyrosine kinases was performed in PC-9 and PC-9/PEM cell lines. We evaluated the efficacy of EGFR and PTK2 co-inhibition in EGFR-TKI-resistant NSCLC in vitro. Oral defactinib and osimertinib were administered in mice bearing subcutaneous xenografts to evaluate the efficacy of the treatment combination in vivo. Both the PTK2 phosphorylation and the treatment combination efficacy were evaluated in erlotinib-resistant EGFR-mutant NSCLC cell lines.ResultsPTK2 was hyperphosphorylated in PC-9/PEM. Defactinib (PTK2 inhibitor) and PD173074 (FGFR inhibitor) inhibited PTK2 phosphorylation. Combination of PTK2 inhibitor and EGFR-TKI inhibited Akt and induced apoptosis in PC-9/PEM. The combination treatment showed improved in vivo therapeutic efficacy compared to the single-agent treatments. Furthermore, erlotinib-resistant NSCLC cell lines showed PTK2 hyperphosphorylation. PTK2 inhibition in the PTK2 hyperphosphorylated erlotinib-resistant cell lines also recovered EGFR-TKI sensitivity.ConclusionPTK2 hyperphosphorylation occurs in various EGFR-TKI-resistant NSCLCs. Combination of PTK2 inhibitor and EGFR-TKI (defactinib and osimertinib) recovered EGFR-TKI sensitivity in the EGFR-TKI-resistant NSCLC. Our study result suggests that this combination therapy may be a viable option to overcome EGFR-TKI resistance in NSCLC.

ABSTRACT. The purposes of this study were to analyze the expression and distribution of human kallikrein 5 (hK5) in triplenegative breast cancer (TNBC) tissues, to establish a standard operating procedure (SOP) for its immunohistochemical assay, and to evaluate the possibility of hK5 being a prognostic biomarker for TNBC. Recombinant hK5 protein and specific antibody were prepared, and the expression and distribution of hK5 in TNBC tissues were detected using immunohistochemistry. An SOP for immunohistochemical staining of hK5 in TNBC tissues was established to allow automatic staining under optimized conditions. The resulting images were digitized for evaluation and statistical analysis via a human scoring system. Our results showed that expression of hK5 protein could predict the progression of TNBC. Pearson's chi-square test results showed that high hK5 expression in tumor stromal cells was significantly correlated with distal metastasis (P = 0.039). A high staining score for lymphocyte infiltration in tumor stroma was significantly correlated with low histological grade of tumor (P = 0.025). Univariate and multivariate Cox regression analyses verified that the staining score for hK5 in tumor stromal cells may be a biomarker for poor prognosis in TNBC patients (univariate HR = 2.289, 95%CI = 1.362-3.848, P = 0.002; multivariate HR = 2.105, 95%CI = 1.189-3.727, P = 0.011). In conclusion, the expression level of hK5 in tumor stromal cells is a promising biomarker for poor prognosis in TNBC. Patients with high histological grade are more prone to distal metastasis and aggressive tumor progression.

Objective: Non-small-cell lung cancer (NSCLC) is one of the most common fatal cancers in the world. Although the treatment of NSCLC has been significantly improved, there is still an unmet need to identify novel targets for developing therapeutic agents and diagnostic/prognostic markers. The aim of this study is explore the role and underlying mechanism of the epithelial splicing regulatory protein (ESRP1) in the development and progression of NSCLC. Methods: A total of 115 participants, 65 cases of NSCLC, 20 cases of precancerous lesions, and 30 cases of benign lung nodules, were included in this study. The expressions of ESRP1 and related transcription factor Twist in enrolled lung tissues were evaluated by histochemistry and immunohistochemistry assay. The survival analysis and related prognosis factors were evaluated by the Kaplan-Meier curve and Cox regression. In addition, the expression of ESRP1 and epithelial-mesenchymal transition (EMT)related transcription factor Twist and EMT markers E-cadherin and N-cadherin were ascertained by immunohistochemical and immunoblotting assay on A549 lung adenocarcinoma cell lines that were exposed to transforming growth factor β1 (TGFβ1). Results: Compared with normal lung tissues, the abundance of ESRP1 protein was significantly increased in precancerous lesions and lung cancer. Correlation analysis demonstrated that ESRP1 was an independent prognostic factor in NSCLC. The expression of ESRP1 and Twist was positively correlated in lung tissues (r = 0.285, p < 0.001). In vitro analysis further showed that TGFβ1 could upregulate the expression of EMT transcription factor Twist while downregulating ESRP1. Conclusions: Our data suggest that the aberrant expression of ESRP1 is an early event in the development of NSCLC. The ESRP1 could serve as a prognostic biomarker for NSCLC, particularly when combined with Twist. The Twist negatively regulated the expression of ESRP1, emphasizing the role of the TGFβ/ESRP1 pathway in the development of NSCLC, which warrants further investigation.