Effects of the NF-κB Pathway Agonist IL-1ß on Non-Small Cell Lung Cancer Cell Lines.

OBJECTIVE: Canakinumab is an interleukin (IL)-1ß inhibitory antibody. Recently, a large trial of canakinumab in cardiac patients described lower lung cancer incidence in patients treated with canakinumab compared to controls. This finding is the basis for ongoing clinical trials of canakinumab in lung cancer. To address the underlying mechanism, we established lung cancer co-cultures to investigate the interactions between lung cancer cells and immunocyte macrophages as related to the expression of IL-1ß and the effect of IL-1ß on the NF-κB pathway on lung cancer cells. METHODS: Lung cancer cell lines H838 and H1975 and macrophages were mono-cultured separately as control groups. Lung cancer cell lines and macrophages were co-cultured respectively in a ratio of 5:1 under the conditions of 37°C in a humidified atmosphere of 5% CO2 for seven days. Cell culture supernatants were collected at predetermined time points, and cell morphology was observed and photographed by microscopy. IL-1ß was detected by ELISA. H838 and H1975 cells were treated with PBS or IL-1ß for 24 hours. Cells were harvested and lysed, then analyzed in a proteome profiler array. RESULTS: Cells in co-cultures initially grew well. IL-1ß was almost undetectable in lung cancer cell lines and macrophage monoculture groups but was highly expressed in co-cultures after 24h and declined at the 7th day. In the H838 and H1975 co-culture group, the lung cancer cells occupied a great majority. IL-1ß activates the NF-κB pathway on H838 and H1975 cells. CONCLUSION: Our data showed that in a lung cancer co-culture incorporating lung cancer cells and macrophages lead to a higher expression of IL-1ß than monoculture. It is possible that such dynamic changes in IL-1ß expression may also occur in vivo in response to changes in the tumor microenvironment and interactions with immune cell populations. These interactions are likely important components to be considered when studying and modeling the expression of IL-1ß as a potential therapeutic target in lung cancer.

The loss-of-function of DNA methyltransferase 1 by siRNA impairs the growth of non-small cell lung cancer with alleviated side effects via reactivation of RASSF1A and APC in vitro and vivo.

Hypermethylation of tumor suppressor genes (TSGs) promoters by DNA methyltransferase (DNMT) can be observed in almost all cancers which represent a hallmark of carcinogenesis, including lung cancer. DNMT inhibitors (e.g.5-Aza-CR/CdR) reactivate TSGs to exert anti-cancer activity and have been applied into the clinical. However, it is cytotoxic even at low concentrations, which might be not directly related to DNA methylation. We here investigated an alternative strategy in the lung cancer therapy and aimed to estimate and compare its efficiency and side effects of knockdown of DNMT1 in vitro and in vivo. Lung cancer tissues (n=20) showed enhanced expression of DNMT1 than corresponding non-neoplastic tissues. Similar results were found in lung cancer cell lines A549 and H538. The treatment of 5-Aza-CR or knockdown of DNMT1 in vitro could inhibit the expressions of DNMT1 but restore the TSGs expressions including the Ras association domain family 1A (RASSF1A) and the adenomatous polyposis coli (APC) via the demethylation of its promoter region, which results in the decreased proliferation, increased apoptosis and impaired ability of migration. Importantly, knockdown of DNMT1 by siRNA in vivo also effectively demethylated the RASSF1A and APC promoter, elevated their expressions and limited tumor growth, which functioned like 5-Aza-CR but with alleviated side effects, suggesting that knockdown of DNMT1 might be potential strategy for the treatment of lung cancer with better tolerability.