Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) have been strikingly effective in lung cancers harboring activating EGFR mutations. Unfortunately, the cancer cells eventually acquire resistance to EGFR-TKI. Approximately 50% of the acquired resistance involves a secondary T790M mutation. To overcome the resistance, we focused on EGFR suppression using microRNA-7 (miR-7), targeting multiple sites in the 3 0 -untranslated region of EGFR mRNA. Two EGFR-TKI-sensitive cell lines (PC-9 and H3255) and two EGFR-TKI-resistant cell lines harboring T790M (RPC-9 and H1975) were used. We constructed miR-7-2 containing miR-7-expressing plasmid. After transfection of the miR-7-expressing plasmid, using cationic liposomes, a quantitative PCR and dual luciferase assay were conducted to examine the efficacy. The antiproliferative effect was evaluated using a cell count assay and xenograft model. Protein expression was examined by Western blotting. The miR-7 expression level of the transfectants was approximately 30-fold higher, and the luciferase activity was ablated by 92%. miR-7 significantly inhibited cell growth not only in PC-9 and H3255 but also in RPC-9 and H1975. Expression of insulin receptor substrate-1 (IRS-1), RAF-1, and EGFR was suppressed in the four cell lines. Injection of the miR-7-expressing plasmid revealed marked tumor regression in a mouse xenograft model using RPC-9 and H1975. EGFR, RAF-1, and IRS-1 were suppressed in the residual tumors. These findings indicate promising therapeutic applications of miR-7-expressing plasmids against EGFR oncogene-addicted lung cancers including T790M resistance by liposomal delivery.

DTP PET/CT with a semiquantitative technique may improve diagnostic capacity for nodal staging of NSCLC.

To investigate the role of an activating epidermal growth factor receptor (EGFR) mutation in lung cancer, we generated transgenic mice expressing the delE748-A752 mutant version of mouse EGFR driven by the SP-C promoter, which is equivalent to the delE746-A750 mutation found in lung cancer patients. Strikingly, the mice invariably developed multifocal lung adenocarcinomas of varying sizes at between 5 and 6 weeks of age, and they died from tumor progression approximately 2 months later if left untreated. Daily oral administration of the EGFR tyrosine kinase inhibitor (TKI) gefitinib (5 mg/kg/day) reduced the total and phosphorylation levels of EGFR to those in wild-type mouse lung tissue; in addition, it abrogated tumor growth within 1 week and prolonged survival to >30 weeks. Interestingly, phosphorylated ErbB2, ErbB3, and thyroid transcriptional factor-1 increased in the transgenic mice compared with those in wild-type mice. They might play some roles in tumors progression in the transgenic mice. This model will be useful for studying the mechanisms of carcinogenesis, chemoprevention, and acquired resistance to EGFR TKIs in lung cancer patients carrying activating EGFR mutations.

Background: Immune checkpoint inhibitors (ICIs) represent a paradigm shift in the development of cancer treatment. However, it remains to be clarified whether the benefits that they confer differ according to patient age. We conducted a systematic review and meta-analysis to assess age differences in the benefits of ICI treatment. Methods: We systematically searched the PubMed database for randomised controlled trials of ICIs, including PD-1, PD-L1 and CTLA-4 inhibitors across multiple cancer types, such as melanoma, lung cancer and gastric cancer. We extracted trials including hazard ratios (HRs) for death stratified by patient age (cut-off age, 65 years). The primary objective of this study was to assess the difference in ICI efficacy between younger and older patients. We calculated pooled HRs and 95% confidence intervals (CIs) for younger and older cancer patients, and assessed data heterogeneity. Results: We identified 3999 studies in our search. Of these, 24 eligible randomised trials, including a total of 8157 (57%) younger and 6104 (43%) older cancer patients, fulfilled the criteria for our study and were thus further analysed. The pooled HRs of the younger and older patients were 0.76 (95% CI: 0.69-0.84) and 0.80 (95% CI: 0.71-0.86), respectively; the difference in ICI efficacy between younger and older cancer patients was not significant (p ¼ .82). Regarding the PD-1 and PD-L1 inhibitors, the survival benefit was similar in both age groups (HR: 0.74; p ¼ .96), whereas for the CTLA-4 inhibitors, there tended to be less survival benefit for older versus younger patients (HR: 0.90 and 0.77, respectively; p ¼ .26). Conclusions: The survival benefit conferred by ICI was not age-dependent, amongst patients aged 65 years or younger. However, age-dependent benefits may vary amongst different types of ICIs.

Molecular agents targeting the epidermal growth factor receptor (EGFR)‐, anaplastic lymphoma kinase (ALK)‐ or c‐ros oncogene 1 (ROS1) alterations have revolutionized the treatment of oncogene‐driven non‐small‐cell lung cancer (NSCLC). However, the emergence of acquired resistance remains a significant challenge, limiting the wider clinical success of these molecular targeted therapies. In this study, we investigated the efficacy of various molecular targeted agents, including erlotinib, alectinib, and crizotinib, combined with anti‐vascular endothelial growth factor receptor (VEGFR) 2 therapy. The combination of VEGFR2 blockade with molecular targeted agents enhanced the anti‐tumor effects of these agents in xenograft mouse models of EGFR‐, ALK‐, or ROS1‐altered NSCLC. The numbers of CD31‐positive blood vessels were significantly lower in the tumors of mice treated with an anti‐VEGFR2 antibody combined with molecular targeted agents compared with in those of mice treated with molecular targeted agents alone, implying the antiangiogenic effects of VEGFR2 blockade. Additionally, the combination therapies exerted more potent antiproliferative effects in vitro in EGFR‐, ALK‐, or ROS1‐altered NSCLC cells, implying that VEGFR2 inhibition also has direct anti‐tumor effects on cancer cells. Furthermore, VEGFR2 expression was induced following exposure to molecular targeted agents, implying the importance of VEGFR2 signaling in NSCLC patients undergoing molecular targeted therapy. In conclusion, VEGFR2 inhibition enhanced the anti‐tumor effects of molecular targeted agents in various oncogene‐driven NSCLC models, not only by inhibiting tumor angiogenesis but also by exerting direct antiproliferative effects on cancer cells. Hence, combination therapy with anti‐VEGFR2 antibodies and molecular targeted agents could serve as a promising treatment strategy for oncogene‐driven NSCLC.