Revisiting Mitochondria Scored Cancer Progression and Metastasis

The Pro-Oncogenic Protein IF1 Promotes Proliferation of Anoxic Cancer Cells during Re-Oxygenation

Cancer cells overexpress IF1, the endogenous protein that inhibits the hydrolytic activity of ATP synthase when mitochondrial membrane potential (ΔμH+) falls, as in ischemia. Other roles have been ascribed to IF1, but the associated molecular mechanisms are still under debate. We investigated the ability of IF1 to promote survival and proliferation in osteosarcoma and colon carcinoma cells exposed to conditions mimicking ischemia and reperfusion, as occurs in vivo, particularly in solid tumors. IF1-silenced and parental cells were exposed to the FCCP uncoupler to collapse ΔμH+ and the bioenergetics of cell models were validated. All the uncoupled cells preserved mitochondrial mass, but the implemented mechanisms differed in IF1-expressing and IF1-silenced cells. Indeed, the membrane potential collapse and the energy charge preservation allowed an increase in both mitophagy and mitochondrial biogenesis in IF1-expressing cells only. Interestingly, the presence of IF1 also conferred a proliferative advantage to cells highly dependent on oxidative phosphorylation when the uncoupler was washed out, mimicking cell re-oxygenation. Overall, our results indicate that IF1, by allowing energy preservation and promoting mitochondrial renewal, can favor proliferation of anoxic cells and tumor growth. Therefore, hindering the action of IF1 may be promising for the therapy of tumors that rely on oxidative phosphorylation for energy production.

MTA1, a Novel ATP Synthase Complex Modulator, Enhances Colon Cancer Liver Metastasis by Driving Mitochondrial Metabolism Reprogramming

Liver metastasis is the most fatal event of colon cancer patients. Warburg effect has been long challenged by the fact of upregulated oxidative phosphorylation (OXPHOS), while its mechanism remains unclear. Here, metastasis-associated antigen 1 (MTA1) is identified as a newly identified adenosine triphosphate (ATP) synthase modulator by interacting with ATP synthase F1 subunit alpha (ATP5A), facilitates colon cancer liver metastasis by driving mitochondrial bioenergetic metabolism reprogramming, enhancing OXPHOS; therefore, modulating ATP synthase activity and downstream mTOR pathways. High-throughput screening of an anticancer drug shows MTA1 knockout increases the sensitivity of colon cancer to mitochondrial bioenergetic metabolism-targeted drugs and mTOR inhibitors. Inhibiting ATP5A enhances the sensitivity of liver-metastasized colon cancer to sirolimus in an MTA1-dependent manner. The therapeutic effects are verified in xenograft models and clinical cases. This research identifies a new modulator of mitochondrial bioenergetic reprogramming in cancer metastasis and reveals a new mechanism on upregulating mitochondrial OXPHOS as the reversal of Warburg effect in cancer metastasis is orchestrated.

Bioactive inorganic nanomaterials for cancer theranostics

Bioactive materials are a special class of biomaterials that can react in vivo to induce a biological response or regulate biological functions, thus achieving a better curative effect than traditional inert biomaterials. For cancer theranostics, compared with organic or polymer nanomaterials, inorganic nanomaterials possess unique physical and chemical properties, have stronger mechanical stability on the basis of maintaining certain bioactivity, and are easy to be compounded with various carriers (polymer carriers, biological carriers, etc.), so as to achieve specific antitumor efficacy. After entering the nanoscale, due to the nano-size effect, high specific surface area and special nanostructures, inorganic nanomaterials exhibit unique biological effects, which significantly influence the interaction with biological organisms. Therefore, the research and applications of bioactive inorganic nanomaterials in cancer theranostics have attracted wide attention. In this review, we mainly summarize the recent progress of bioactive inorganic nanomaterials in cancer theranostics, and also introduce the definition, synthesis and modification strategies of bioactive inorganic nanomaterials. Thereafter, the applications of bioactive inorganic nanomaterials in tumor imaging and antitumor therapy, including tumor microenvironment (TME) regulation, catalytic therapy, gas therapy, regulatory cell death and immunotherapy, are discussed. Finally, the biosafety and challenges of bioactive inorganic nanomaterials are also mentioned, and their future development opportunities are prospected. This review highlights the bioapplication of bioactive inorganic nanomaterials.

Mitochondrial Control in Inflammatory Gastrointestinal Diseases

Mitochondria play a central role in the pathophysiology of inflammatory bowel disease (IBD) and colorectal cancer (CRC). The maintenance of mitochondrial function is necessary for a stable immune system. Mitochondrial dysfunction in the gastrointestinal system leads to the excessive activation of multiple inflammatory signaling pathways, leading to IBD and increased severity of CRC. In this review, we focus on the mitochondria and inflammatory signaling pathways and its related gastrointestinal diseases.

HMOX1 promotes lung adenocarcinoma metastasis by affecting macrophages and mitochondrion complexes

Background

Metastasis is the leading cause of lung adenocarcinoma (LUAD) patient death. However, the mechanism of metastasis is unclear. We performed bioinformatic analyses for HMOX1 (Heme oxygenase-1), aiming to explore its role in LUAD metastasis.

Methods

Pan-cancer analysis was first used to identify the metastasis-associated role of HMOX1 in LUAD. HMOX1-related genomic alterations were then investigated. Based on functional enrichment, we systematically correlated HMOX1 with immunological characteristics and mitochondrial activities. Furthermore, weighted gene co-expression network analysis (WGCNA) was applied to construct the HMOX1-mediated metastasis regulatory network, which was then validated at the proteomic level. Finally, we conducted the survival analysis and predicted the potential drugs to target the HMOX1 network.

Results

HMOX1 expression was significantly associated with epithelial-mesenchymal transition (EMT) and lymph and distant metastasis in LUAD. High HMOX1 levels exhibited higher macrophage infiltration and lower mitochondrial complex expression. WGCNA showed a group of module genes co-regulating the traits mentioned above. Subsequently, we constructed an HMOX1-mediated macrophage-mitochondrion-EMT metastasis regulatory network in LUAD. The network had a high inner correlation at the proteomic level and efficiently predicted prognosis. Finally, we predicted 9 potential drugs targeting HMOX1-mediated metastasis in LUAD, like chloroxine and isoliquiritigenin.

Conclusions

Our analysis elaborates on the role of HMOX1 in LUAD metastasis and identified a highly prognostic HMOX1-mediated metastasis regulatory network. Novel potential drugs targeting the HMOX1 network were also proposed, which should be tested for their activity against LUAD metastasis in future studies.

Mitochondrial dynamics regulators: implications for therapeutic intervention in cancer

Regardless of the recent advances in therapeutic developments, cancer is still among the primary causes of death globally, indicating the need for alternative therapeutic strategies. Mitochondria, a dynamic organelle, continuously undergo the fusion and fission processes to meet cell requirements. The balanced fission and fusion processes, referred to as mitochondrial dynamics, coordinate mitochondrial shape, size, number, energy metabolism, cell cycle, mitophagy, and apoptosis. An imbalance between these opposing events alters mitochondWangrial dynamics, affects the overall mitochondrial shape, and deregulates mitochondrial function. Emerging evidence indicates that alteration of mitochondrial dynamics contributes to various aspects of tumorigenesis and cancer progression. Therefore, targeting the mitochondrial dynamics regulator could be a potential therapeutic approach for cancer treatment. This review will address the role of imbalanced mitochondrial dynamics in mitochondrial dysfunction during cancer progression. We will outline the clinical significance of mitochondrial dynamics regulators in various cancer types with recent updates in cancer stemness and chemoresistance and its therapeutic potential and clinical utility as a predictive biomarker.

High mitochondrial content is associated with breast cancer aggressiveness

Mitochondria are relevant for cancer initiation and progression. Antibodies against mitochondrially encoded cytochrome c oxidase II (MTCO2), targeting a mitochondria specific epitope, can be used to quantitate the mitochondria content of tumor cells. The present study evaluated the impact of the cellular mitochondrial content on the prognosis of patients with breast cancer using immunohistochemical analysis on 2,197 arrayed breast cancer specimens. Results were compared with histological tumor parameters, patient overall survival, tumor cell proliferation using Ki67 labeling index (Ki67LI) and various other molecular features. Tumor cells exhibited stronger MTCO2 expression than normal breast epithelial cells. MTCO2 immunostaining was largely absent in normal breast epithelium, but was observed in 71.9% of 1,797 analyzable cancer specimens, including 34.6% tumors with weak expression, 22.3% with moderate expression and 15.0% with strong expression. High MTCO2 expression was significantly associated with advanced tumor stage, high Bloom-Richardson-Elston/Nottingham (BRE) grade, nodal metastasis and shorter overall survival (P<0.0001 each). In multivariate analysis, MTCO2 expression did not provide prognostic information independent of BRE grade, pathological tumor and pathological lymph node status. Additionally, significant associations were observed for high MTCO2 expression and various molecular features, including high Ki67LI, amplifications of HER2, MYC, CCND1 and MDM2, deletions of PTEN, 8p21 and 9p, low estrogen receptor expression (P<0.0001 each) and progesterone receptor expression (P<0.0001). The present study demonstrated that high MTCO2 expression was strongly associated with a poor prognosis and unfavorable phenotypical and molecular tumor features in patients with breast cancer. This suggests that the mitochondrial content may have a pivotal role in breast cancer progression.