Inhibitory Impact Of Cinobufagin In Triple-Negative Breast Cancer Metastasis: Involvements Of Macrophage Reprogramming Through Upregulated MME and Inactivated FAK/STAT3 Signaling.

Cinobufagin (CBG), a key bioactive component in cinobufacini, exhibits antitumor properties. This study explores CBG's impact on triple-negative breast cancer (TNBC) metastasis and elucidates the underpinning mechanism. Murine xenograft and orthotopic metastatic TNBC models were generated and treated with CBG. The burden of metastatic tumor in the mouse lung, the epithelial to mesenchymal transition (EMT) markers, and macrophage polarization markers within the tumors were examined. The phenotype of tumor-associated macrophages (TAMs) and mobility of TNBCs in vitro in a macrophage-TNBC cell coculture system were analyzed. Physiological targets of CBG were identified by bioinformatics analyses. CBG treatment significantly alleviated lung tumor burden and EMT activity. It triggered an M2-to-M1 shift in TAMs, resulting in decreased TNBC cell migration, invasion, and EMT in vitro. CBG upregulated membrane metalloendopeptidase (MME) expression, suppressing FAK and STAT3 phosphorylation. Silencing of MME, either in mice or TAMs, counteracted CBG effects, reinstating M2 TAM predominance and enhancing TNBC cell metastasis. Cotreatment with Defactinib, a FAK antagonist, reversed M2 TAM polarization and TNBC cell metastasis. Notably, MME silencing in TNBC cells had no impact on CBG-suppressed malignant properties, indicating MME's indirect involvement in TNBC cell behavior through TAM mediation. This study unveils CBG's ability to enhance MME expression, deactivate FAK/STAT3 signaling, and inhibit TNBC metastasis by suppressing M2-skewed macrophages.

Zhu Z ，Wang H ，Qian X ，Xue M ，Sun A ，Yin Y ，Tang J ，Zhang J ... -  《-》

Taraxacum mongolicum extract inhibited malignant phenotype of triple-negative breast cancer cells in tumor-associated macrophages microenvironment through suppressing IL-10 / STAT3 / PD-L1 signaling pathways.

Triple-negative breast cancer (TNBC) is the most aggressive and the worst prognosis breast cancer with limited treatment options. Taraxacum mongolicum (also called dandelion) is a traditional Chinese medicine has been used to treat mastitis, breast abscess, and hyperplasia of mammary glands since ancient times. In modern pharmacological research, dandelion has been proven with anti-breast cancer activities. We previously reported that dandelion extract could induce apoptosis in TNBC cells. However, its anti-tumor effects and mechanisms in the tumor microenvironment have not yet been elucidated. Tumor-associated macrophages (TAMs) play an important role in regulating the interaction between tumor cells and the immune system. The present study aimed to investigate the effects and mechanisms of dandelion extract on TNBC cells under the microenvironment of TAMs, as well as its influence on the polarization of M2 macrophages. M2 macrophages were induced by phorbol-12-myristate 13-acetate (PMA) and interleukin 4 (IL-4), and verified by flow cytometry, quantitative RT-PCR (qRT-PCR), Western blotting, and ELISA. MDA-MB-231 and MDA-MB-468 TNBC cells were co-cultured with the supernatant of M2 macrophage which providing the TAMs microenvironment. The antitumor activity of dandelion extract in TNBC cells was evaluated by MTT assay. The invasive and migratory capacity of TNBC cells was measured by transwell assays. The expression of protein and gene was assessed by Western blotting and qRT-PCR, respectively. TAMs microenvironment promoted the proliferation, migration, and invasion of TNBC cells. However, dandelion extract inhibited the malignant property of MDA-MB-231 and MDA-MB-468 cells induced by TAMs. Both of TAMs and IL-10 caused STAT3 activation and PD-L1 higher expression, the immunosuppressive molecules in TNBC cells, and this effect can be attenuated by IL-10 neutralizing antibody. Dandelion extract exerted inhibition on STAT3 and PD-L1 in TNBC cells under TAMs microenvironment. Furthermore, in M2 macrophages, dandelion extract remarkably promoted the expression of M1-like marker TNF-α, IL-8, and iNOS, but reduced M2-like marker IL-10, CD206, Arginase-1, and TGF-β. Dandelion extract inhibited the proliferation, migration and invasion of TNBC cells in TAMs microenvironment through suppressing IL-10/STAT3/PD-L1 immunosuppressive signaling pathway. Furthermore, dandelion extract promoted the polarization of macrophages from M2 to M1 phenotype. Thus, our results indicated that dandelion may serve as a promising therapeutic strategy for TNBC by modulating tumor immune microenvironment.

Deng XX ，Jiao YN ，Hao HF ，Xue D ，Bai CC ，Han SY ... -  《-》

Lidocaine combined with general anesthetics impedes metastasis of breast cancer cells via inhibition of TGF-β/Smad-mediated EMT signaling by reprogramming tumor-associated macrophages.

Seok Han B ，Ko S ，Seok Park M ，Ji Lee Y ，Eun Kim S ，Lee P ，Jin Cho Y ，Gyeol Go H ，Kwak S ，Park E ，Lim A ，Lee S ，Yoo S ，Kim H ，Hee Jung K ，Hong SS ... -  《-》

Tamoxifen reverses epithelial-mesenchymal transition by demethylating miR-200c in triple-negative breast cancer cells.

Wang Q ，Cheng Y ，Wang Y ，Fan Y ，Li C ，Zhang Y ，Wang Y ，Dong Q ，Ma Y ，Teng YE ，Qu X ，Liu Y ... -  《BMC CANCER》

Tumor-associated macrophages promote epithelial-mesenchymal transition and the cancer stem cell properties in triple-negative breast cancer through CCL2/AKT/β-catenin signaling.

Triple-negative breast cancer (TNBC) is a highly aggressive subtype of breast cancer with poor prognosis and limited treatment. As a major component of the tumor microenvironment, tumor-associated macrophages (TAMs) play an important role in facilitating the aggressive behavior of TNBC. This study aimed to explore the novel mechanism of TAMs in the regulation of epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC) properties in TNBC. Expression of the M2-like macrophage marker CD163 was evaluated by immunohistochemistry in human breast cancer tissues. The phenotype of M2 macrophages polarized from Tohoku-Hospital-Pediatrics-1 (THP1) cells was verified by flow cytometry. Transwell assays, wound healing assays, western blotting, flow cytometry, ELISA, quantitative polymerase chain reaction (qPCR), luciferase reporter gene assays, and immunofluorescence assays were conducted to investigate the mechanism by which TAMs regulate EMT and CSC properties in BT549 and HCC1937 cells. Clinically, we observed a high infiltration of M2-like tumor-associated macrophages in TNBC tissues and confirmed that TAMs were associated with unfavorable prognosis in TNBC patients. Moreover, we found that conditioned medium from M2 macrophages (M2-CM) markedly promoted EMT and CSC properties in BT549 and HCC1937 cells. Mechanistically, we demonstrated that chemokine (C-C motif) ligand 2 (CCL2) secretion by TAMs activated Akt signaling, which in turn increased the expression and nuclear localization of β-catenin. Furthermore, β-catenin knockdown reversed TAM-induced EMT and CSC properties. This study provides a novel mechanism by which TAMs promote EMT and enhance CSC properties in TNBC via activation of CCL2/AKT/β-catenin signaling, which may offer new strategies for the diagnosis and treatment of TNBC. Video Abstract.

Chen X ，Yang M ，Yin J ，Li P ，Zeng S ，Zheng G ，He Z ，Liu H ，Wang Q ，Zhang F ，Chen D ... -  《Cell Communication and Signaling》