BackgroundTriple-negative breast cancer (TNBC) is a poor prognostic breast cancer with the highest mutations and limited therapeutic choices. Cytokine networking between cancer cells and the tumor microenvironment (TME) maintains the self-renewing subpopulation of breast cancer stem cells (BCSCs) that mediate tumor heterogeneity, resistance and recurrence. Immunotherapy of those factors combined with targeted therapy or chemoagents may advantage TNBC treatment.ResultsWe found that the oncogene Multiple Copies in T-cell Malignancy 1 (MCT-1/MCTS1) expression is a new poor-prognosis marker in patients with aggressive breast cancers. Overexpressing MCT-1 perturbed the oncogenic breast epithelial acini morphogenesis and stimulated epithelial-mesenchymal transition and matrix metalloproteinase activation in invasive TNBC cells, which were repressed after MCT-1 gene silencing. As mammary tumor progression was promoted by oncogenic MCT-1 activation, tumor-promoting M2 macrophages were enriched in TME, whereas M2 macrophages were decreased and tumor-suppressive M1 macrophages were increased as the tumor was repressed via MCT-1 knockdown. MCT-1 stimulated interleukin-6 (IL-6) secretion that promoted monocytic THP-1 polarization into M2-like macrophages to increase TNBC cell invasiveness. In addition, MCT-1 elevated the soluble IL-6 receptor levels, and thus, IL-6R antibodies antagonized the effect of MCT-1 on promoting M2-like polarization and cancer cell invasion. Notably, MCT-1 increased the features of BCSCs, which were further advanced by IL-6 but prevented by tocilizumab, a humanized IL-6R antibody, thus MCT-1 knockdown and tocilizumab synergistically inhibited TNBC stemness. Tumor suppressor miR-34a was induced upon MCT-1 knockdown that inhibited IL-6R expression and activated M1 polarization.ConclusionsThe MCT-1 pathway is a novel and promising therapeutic target for TNBC.Electronic supplementary materialThe online version of this article (10.1186/s12943-019-0988-0) contains supplementary material, which is available to authorized users.

Upregulation of E2F1 and STMN1 proteins associate with worse outcomes in patients with HCC. E2F1 significantly correlates with STMN1 protein level in HCC lesions and in vitro transactivation assays, suggesting that STMN1 gene is transactivated by the E2F1 protein.

Low-molecular-weight Fucoidan (Oligo-Fucoidan) is a sulfated polysaccharide that has a variety of biological effects and has also been shown to have beneficial health effects. However, the molecular mechanisms underlying the therapeutic effects of Oligo-Fucoidan in patients with cancer remain unclear. Using human colorectal cancer HCT116 cells with (p53+/+) or without (p53−/−) normal p53 expression, we found that Oligo-Fucoidan treatment reduces the occurrence of spontaneous DNA lesions. Etoposide induces double strand DNA breaks. Subsequent administration of Oligo-Fucoidan to etoposide-treated cells promotes p53 accumulation, p21 expression and significant decreases in ataxia-telangiectasia-mutated (ATM), checkpoint kinase 1 (Chk1) and γ-H2AX phosphorylation in p53+/+ cells compared with p53−/− cells. Similarly, co-administration of Oligo-Fucoidan with etoposide inhibits ATM, Chk1 and γ-H2AX phosphorylation, particularly in the presence of p53. Furthermore, Oligo-Fucoidan supplementation increases cancer cell death and attenuates the adverse effects induced by etoposide that decreases production of the pro-inflammatory cytokine IL-6 and chemokine CCL2/MCP-1. Importantly, Oligo-Fucoidan decreases the tumor-promoting M2 macrophages in microenvironment as well as collaborates with p53 and works in combination with etoposide to prevent HCT116 tumorigenicity. Our results first demonstrate that p53 enables Oligo-Fucoidan to effectively inhibit tumor progression, and Oligo-Fucoidan minimizes the side effects of chemotherapy and alters tumor microenvironment.

Reactive oxygen species (ROS) produced during intracellular metabolism or triggered by extrinsic factors can promote neoplastic transformation and malignant microenvironment that mediate tumor development. Oligo-Fucoidan is a sulfated polysaccharide isolated from the brown seaweed. Using human THP-1 monocytes and murine Raw264.7 macrophages as well as human HCT116 colorectal cancer cells, primary C6P2-L1 colorectal cancer cells and human MDA-MB231 breast cancer cells, we investigated the effect of Oligo-Fucoidan on inhibiting M2 macrophage differentiation and its therapeutic potential as a supplement in chemotherapy and tumor prevention. We now demonstrate that Oligo-Fucoidan is an antioxidant that suppresses intracellular ROS and mitochondrial superoxide levels in monocytes/macrophages and in aggressive cancer cells. Comparable to ROS inhibitors (DPI and NAC), Oligo-Fucoidan directly induced monocyte polarization toward M1-like macrophages and repolarized M2 macrophages into M1 phenotypes. DPI and Oligo-Fucoidan also cooperatively prevented M2 macrophage invasiveness. Indirectly, M1 polarity was advanced particularly when DPI suppressed ROS generation and supplemented with Oligo-Fucoidan in the cancer cells. Moreover, cisplatin chemoagent polarized monocytes and M0 macrophages toward M2-like phenotypes and Oligo-Fucoidan supplementation reduced these side effects. Furthermore, Oligo-Fucoidan promoted cytotoxicity of cisplatin and antagonized cisplatin effect on cancer cells to prevent M2 macrophage differentiation. More importantly, Oligo-Fucoidan inhibited tumor progression and M2 macrophage infiltration in tumor microenvironment, thus increasing of anti-tumor immunity.

Triple-negative breast cancer (TNBC) has been shown with high mitochondrial oxidative phosphorylation and production of reactive oxygen species (ROS). MnSOD (SOD2) is a mitochondrial antioxidant defense that has been implicated in inhibition of human malignancies. However, the impact of MnSOD on immunosuppressive macrophage functions and TNBC aggressiveness has never been explored. We found here that SOD2high is primarily observed in the aggressive subtypes of HER2(+) breast cancers and TNBCs patients. Further analyses demonstrated that the oncoprotein multiple copies in T-cell malignancy-1 (MCT-1 or MCTS1) induces mitochondrial superoxide dismutase (MnSOD) in TNBC cells by stabilizing the transcription factor Nrf2. SOD2high/MCTS1high expression correlates with a poor prognosis in breast cancer patients. MnSOD in TNBC cells functions as a prooxidant peroxidase that increases mitochondrial ROS (mROS) and adaptation to oxidative stress under the oncogenic effect. Interleukin-6 (IL-6) in the MCT-1 pathway elevates Nrf2/MnSOD and mROS levels. Knockdown of MnSOD inhibits TNBC cell invasion, breast cancer stem cells (BCSCs), mROS, and IL-6 excretion promoted by MCT-1. TNBC cells deficient in MnSOD prevent the polarization and chemotaxis of M2 macrophages but improve the ability of M1 macrophages to engulf cancer cells. Quenching mROS with MitoQ, a mitochondria-targeted non-metal-based antioxidant MnSOD mimics, effectively suppresses BCSCs and M2 macrophage invasion exacerbated by MnSOD and MCT-1. Consistently, silencing MnSOD impedes TNBC progression and intratumoral M2 macrophage infiltration. We revealed a novel stratagem for TNBC management involving targeting the MCT-1 oncogene-induced mitochondrial prooxidant MnSOD pathway, which prevents the development of an immunosuppressive tumor microenvironment.

Multiple copies in T-cell malignancy 1 (MCT-1) is involved in transcription regulation and translation initiation. We have identified that MCT-1 plays important roles in cell transformation and survival, catastrophic mitosis and genomic instability. Enhanced MCT-1 activity decreases p53 promoter function, protein stability and activity, thereby overexpressing MCT-1 further promotes tumorigenicity in a p53-null background. Enhanced MCT-1 activation induces SHCs (Src homology 2 domain containing transforming proteins) that transmit EGFR signaling to extracellular-regulated kinase (ERK) and AKT pathway. Here, we identify a novel carcinoma metabolism pathway involving MCT-1-YY1-EGFR-MnSOD axis which confers oxidative resistance, changes tumor microenvironments and promotes tumor development. Inhibiting this oncogenic pathway may be a novel clinical intervention approach to prevent tumor progression and metastasis. Aims: Reactive oxygen species (ROS) promote tumor progression and metastasis, but the underlying mechanism remains unclear. We aim to investigate whether the oncogenic pathway enhances the generation of ROS, alters tumor microenvironment and potentiates metastasis. Results: We found that oncogene MCT-1 (multiple copies in T-cell malignancy 1) stimulated intracellular ROS formation and mitochondrial superoxide production in relationship with the deregulation of antioxidants and redox signaling. Enhanced MCT-1 activation induced the YY1-EGFR-MnSOD signaling cascade which prevented cells against oxidative damage and promoted tumor development. Importantly, MCT-1 overexpressing in lung cancer cells promoted tumor angiogenesis and necrosis along with increase of tumor-promoted M2 macrophages and cancer-associated myofibroblasts in stroma, which potentially provided a malignant microenvironment for tumor progression and metastasis. Conversely, restricting ROS generation and targeting YY1 suppressed the MCT-1-EGFR-MnSOD pathway and invasion ability in lung cancer cells. Clinical results confirm that MCT-1 overexpression is link to poor clinical outcomes and associates with hyper-activation of YY1, EGFR and MnSOD in patients with lung cancer. Importantly, MCT-1 protein enrichment is often identified in late stage and lymph node metastasis of lung cancer. Innovation and Conclusion: Our data reveal a previously unrecognized mechanism of the oxidative metabolism involving MCT-1-YY1-EGFR-MnSOD network which alters tumor microenvironments and promotes tumor progression and metastasis. Citation Format: Hong-Yu Tseng, Yen-An Chen, Jayu Jen, Yi-Ching Wang, Hsin-Ling Hsu. Oncogenic MCT-1 activation deregulates oxidative metabolism and promotes lung tumor progression and metastasis. [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr A30.

Hepatocellular carcinoma (HCC) is one of the most deadly malignancies worldwide due to its high recurrence rate, high metastatic potential, and resistance to drugs. Elucidation of the mechanisms underlying malignancy in HCC is needed to improve diagnosis, therapy, and prognosis. Previously, we showed that TG‐interacting factor (TGIF) antagonizes arsenic trioxide‐induced apoptosis of HepG2 cells and is associated with poor prognosis and progression of urothelial carcinoma in patients after radical nephroureterectomy. To determine whether TGIF plays a role in HCC tumorigenesis, we compared the expression of TGIF, its downstream targets, and ROS levels between HCC HepG2 cells and the more invasive SK‐Hep1 cells. Superoxide production, phosphorylation of c‐SrcY416 and AKTS473, and expression of TGIF and NADPH oxidase (Nox) were higher in invasive SK‐Hep1 cells than in HepG2 cells. TGIF‐overexpressing HepG2 xenograft tumors markedly promoted tumor growth and metastasis to the lungs. Overexpression of TGIF in HepG2 cells increased superoxide production from Nox4, MMP expression, invadopodia formation, and cellular migration/invasion ability. Conversely, knockdown of TGIF in SK‐Hep1cells attenuated these processes. Using gene knockdown and pharmacological inhibitors, we demonstrate that c‐Src/AKT is the upstream signaling that regulates TGIF‐induced Nox4 activation and subsequent superoxide production. Taken together, our results implicate TGIF as a potential biomarker for prognosis and target for clinical therapy in patients with advanced HCC.

The underlying mechanism of oncogene activation that induces reactive oxygen species (ROS) generation and promotes tumor progression and metastasis is still ambiguous. We now demonstrate that the oncogenic MCT-1 activation protects cells from oxidative damage via increase of YY1 and subsequently enhances EGFR expression and activation. Overexpressing MCT-1 induces cell invasion, intracellular ROS generation and MnSOD expression in mitochondria via YY1 pathway, thus targeting YY1 suppresses cancer cell invasion and blocks EGFR-MnSOD signaling function enhanced by MCT-1. Recapitulating in vitro outcomes, MCT-1 increment promotes tumor angiogenesis, necrosis and metastasis with oxidative metabolism deregulation and malignant microenvironment development in xenograft mice. Clinical data also confirms that MCT-1 enrichment connects to poor survival and prognosis coincident with YY1, EGFR and MnSOD upregulation in patients with lung cancer. Collectively, MCT-1 is a key inducer of YY1-EGFR-MnSOD axis involving the redox mechanism in the process of carcinogenesis. Citation Format: Hong-Yu Tseng, Yen-An Chen, Yi-Rong Chen, Hsin-Ling Hsu. Oncogene MCT-1 deregulates oxidative metabolism and promotes tumor metastasis via YY1 signaling network. [abstract]. In: Proceedings of the AACR Special Conference: Function of Tumor Microenvironment in Cancer Progression; 2016 Jan 7–10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2016;76(15 Suppl):Abstract nr B02.