MiR-301a-3p Suppresses Estrogen Signaling by Directly Inhibiting ESR1 in ERα Positive Breast Cancer.

Background/aims: MiRNA-301a-3p is an oncogenic miRNA whose expression is associated with tumor development, metastases and overall poor prognosis. Estrogen receptor α (ERα) is one of the estrogen hormone-activated transcription factors, which regulates a large number of genes and is involved in the mammary gland development. Expression of ERα is considered to be a good indicator for endocrine therapy and breast cancer survival.

Selective Disruption of Respiratory Supercomplexes as a New Strategy to Suppress Her2 Breast Cancer.

Aims: Expression of the HER2 oncogene in breast cancer is associated with resistance to treatment, and Her2 may regulate bioenergetics. Therefore, we investigated whether disruption of the electron transport chain (ETC) is a viable strategy to eliminate Her2 disease.

Results: We demonstrate that Her2 cells and tumors have increased assembly of respiratory supercomplexes (SCs) and increased complex I-driven respiration in vitro and in vivo.

The effect of mitochondrially targeted anticancer agents on mitochondrial (super)complexes.

The mitochondrial respiratory chain is organized into dynamic high molecular weight complexes that associate to form supercomplexes. The function of these SCs is to minimize the production of reactive oxygen species (ROS) generated during electron transfer within them and to efficiently transfer electrons to complex IV. These supra-molecular structures as well as whole mitochondria are stress-responsive and respond to mitochondrially targeted anti-cancer agent by destabilization and induction of massive production of ROS leading to apoptosis.

Mitochondrially targeted vitamin E succinate modulates expression of mitochondrial DNA transcripts and mitochondrial biogenesis.

Aims: To assess the effect of mitochondrially targeted vitamin E (VE) analogs on mitochondrial function and biogenesis.

Results: Mitochondrially targeted vitamin E succinate (MitoVES) is an efficient inducer of apoptosis in cancer cells. Here, we show that unlike its untargeted counterpart α-tocopheryl succinate, MitoVES suppresses proliferation of cancer cells at sub-apoptotic doses by way of affecting the mitochondrial DNA (mtDNA) transcripts.

Mitochondrial genome acquisition restores respiratory function and tumorigenic potential of cancer cells without mitochondrial DNA.

We report that tumor cells without mitochondrial DNA (mtDNA) show delayed tumor growth, and that tumor formation is associated with acquisition of mtDNA from host cells. This leads to partial recovery of mitochondrial function in cells derived from primary tumors grown from cells without mtDNA and a shorter lag in tumor growth. Cell lines from circulating tumor cells showed further recovery of mitochondrial respiration and an intermediate lag to tumor growth, while cells from lung metastases exhibited full restoration of respiratory function and no lag in tumor growth.

Mitochondrial targeting of α-tocopheryl succinate enhances its anti-mesothelioma efficacy.

Unlabelled: Malignant mesothelioma (MM) is a fatal neoplastic disease with no therapeutic option. Therefore, the search for novel therapies is of paramount importance.

Methods: Since mitochondrial targeting of α-tocopheryl succinate (α-TOS) by its tagging with triphenylphosphonium enhances its cytotoxic effects to cancer cells, we tested its effect on MM cells and experimental mesotheliomas.

Antiproliferative and antiangiogenic effects of flavone eupatorin, an active constituent of chloroform extract of Orthosiphon stamineus leaves.

Flavone eupatorin is one of the constituents of Orthosiphon stamineus, a medicinal herb used in folk medicine in South East Asia for treatment of various disorders. In our study, we investigated the antiproliferative properties of a chloroform extract of the leaves of O. stamineus and of pure eupatorin.