Gefitinib inhibits M2-like polarization of tumor-associated macrophages in Lewis lung cancer by targeting the STAT6 signaling pathway.

M2-like polarized tumor-associated macrophages (TAMs) play a pivotal role in promoting cancer cell growth, invasion, metastasis and angiogenesis. The identification of M2-like TAMs during tumor progression is an attractive approach for cancer therapy. In this study, we investigated the relevance of macrophage polarization and the antitumor effect of gefitinib in Lewis Lung cancer (LLC) in vitro and in vivo. Gefitinib at a concentration below 2.5 µmol/L did not cause significant growth inhibition on LLC and RAW 264.7 cell lines and bone marrow-derived macrophage (BMDMs). However, a small concentration of gefitinib (0.62 µmol/L) significantly inhibited IL-13-induced M2-like polarization of macrophages, evidenced by the decreased expression of the M2 surface markers CD206 and CD163, down-regulation of specific M2-marker genes (Mrc1, Ym1, Fizz1, Arg1, IL-10 and CCL2) as well as inhibition of M2-like macrophage-mediated invasion and migration of LLC cells. In RAW 264.7 cells, gefitinib inhibits IL-13-induced phosphorylation of STAT6, which was a crucial signaling pathway in macrophage M2-like polarization. In LLC mice metastasis model, oral administration of gefitinib (75 mg·kg-1·d-1, for 21 d) significantly reduced the number of lung metastasis nodules, down-regulated the expression of M2 marker genes and the percentages CD206+ and CD68+ macrophages in tumor tissues. These results demonstrated that gefitinib effectively inhibits M2-like polarization both in vitro and in vivo, revealing a novel potential mechanism for the chemopreventative effect of gefitinib.

[Advances in study of macrophages in chemotherapy resistance of cancer].

As extremely important inflammatory cells in the tumor microenvironment, tumor-associated macrophages (TAMs) can secrete a variety of chemokines and cytokines, which play an important role in the occurrence of tumor growth and metastasis. Recent years, increasing studies have shown that macrophages are associated with tumor chemotherapy sensitivity. The chemical substances produced by macrophages affect the efficacy of chemotherapeutic agents. In addition, some chemotherapeutic agents have an effect on the recruitment and bioactivity of macrophages in the tumor issue, which influences the anti-tumor efficacy of chemotherapy drugs. In this review, we summarize the roles of macrophages in the chemotherapy resistance, including the regulatory mechanism and the strategy of targeting macrophages.

[Combination of lapatinib with chlorogenic acid inhibits breast cancer metastasis by suppressing macrophage M2 polarization].

OBJECTIVE: To determine the effect of the combination of lapatinib with chlorogenic acid on metastasis of breast cancer in mouse model. METHODS: The classical macrophage M2 polarization model induced by interlukin13in vitro was adopted in the study. Flow cytometric analysis was performed to detect the expression of M2 marker CD206. The transcription of M2-associated genes was measured by RT-PCR. HE staining was used to analyze the metastatic nodes of breast cancer in lungs of MMTV-PyVT mice. Immunostaining analysis was used to detect the expression of related proteins in breast cancer. RESULTS: The combination of lapatinib and chlorogenic acid inhibited the expression of CD206 induced by IL-13[(42.17%±2.59%) vs (61.15%±7.58%), P<0.05]. The combination more markedly suppressed expression of M2-associated gene Ym1 than lapatinib alone[(0.9±0.1) vs (1.8±0.0), P<0.05]. The combination of lapatinib and chlorogenic acid significantly reduced metastatic nodes in lung[P<0.05], and also significantly decreased the percentage of CD206(+) cells in breast cancer compared to controls[(6.08%±2.60%) vs(29.04%±5.86%), P<0.05]. CONCLUSION: The combination of lapatinib and chlorogenic acid can effectively inhibit macrophage M2 polarization and metastasis of breast cancer.

[Statins enhance anti-tumor effect of suberoylanilide hydroxamic acid on human non-small cell lung carcinoma cells].

OBJECTIVE: To evaluate the anti-tumor effect of the combination of suberoylanilide hydroxamic acid(SAHA) with statins(lovastatin or simvastatin) on non-small cell lung carcinoma(NSCLC) cells. METHODS: Human NSCLC A549 cells were treated with SAHA in combination of lovastatin or simvastatin. The cell growth was analyzed by SRB method, and the apoptosis of A549 cells was assessed by flow cytometer. The expression of cleaved poly-ADP-ribose polymerase(cleaved-PARP) and p21 protein was analyzed by Western-blotting when A549 cells were challenged with 2.5µmol/L SAHA and 5µmol/L lovastatin. RESULTS: Lovastatin and simvastatin synergized SAHA in the inhibition of A549 cells. SAHA induced apoptosis was also enhanced by lovastatin. Treatment with 2.5µmol/L SAHA significantly up-regulated the expression of p21 protein in 48 h, while the protein expression was reduced in combined treatment with 5µmol/L lovastatin. CONCLUSION: Statins can synergize the anti-tumor effect of SAHA in human NSCLC cells through a p21-dependent way.