Project description:Introduction: The flavonoid myricetin has been shown to induce cell cycle arrest and mitochondrial-dependent apoptosis in preclinical cancer models. We hypothesised that myricetin-derived flavonoids with redox properties and improved physicochemical attributes that enhance cell uptake and mitochondrial targeting might have increased potential as antitumour agents, since mitochondria are the main site of production of reactive oxygen species (ROS) and redox status is known to regulate the development and advancement of certain cancers. In this study we assessed a small library of novel flavonoids, then focussed on the lead compound, second-generation analogue OncamexTM, its mechanism of action and structure-activity relationships as an anti-proliferative agent. Methods: With this aim, we studied the effect of OncamexTM in a panel of 7 breast cancer cell lines using proliferation, cytotoxicity and apoptosis assays. The redox properties and mitochondrial delivery of the drug were studied using cyclic voltammetry and fluorescence microscopy, respectively. The mechanism of action was further studied using western blotting, gene expression analysis and immunohistochemistry (IHC) of treated xenograft tissue from in vivo mice models. Results: Sulforhodamine B (SRB) proliferation assays demonstrated strong, anti-proliferative properties of OncamexTM, with IC50 values in the low micromolar range. Treatment for 8 h exerted concentration-dependent reduction in cell viability and induction of cytotoxicity and apoptosis, with increased caspase activation. Microarray analysis suggested that OncamexTM regulates changes in cell cycle and apoptosis at gene expression level. Fluorescence microscopy was used to investigate mitochondrial targeting and ROS regulation in treated cells. OncamexTM was found to induce production of superoxide at concentrations which exerted anti-proliferative effects. Initial in vivo studies in mice implanted with a MDA-MB-231 breast cancer xenograft showed that OncamexTM inhibited tumour growth, reducing tissue viability and Ki-67 proliferation, with no overall systemic toxicity. Conclusions: OncamexTM is a novel flavonoid capable of specific delivery to the mitochondria and induction of ROS production. We have shown its antitumor activity in preclinical models of breast cancer, both in vitro and in initial in vivo models, where tumour growth was arrested without inducing toxicity, support the potential of this novel drug for its continued development as an anticancer agent. Total RNA was obtained from 5 breast cancer cell lines subjected to 6 hours of 10µM OncamexTM and matched untreated controls (1% DMSO)

Project description:Introduction: The flavonoid myricetin has been shown to induce cell cycle arrest and mitochondrial-dependent apoptosis in preclinical cancer models. We hypothesised that myricetin-derived flavonoids with redox properties and improved physicochemical attributes that enhance cell uptake and mitochondrial targeting might have increased potential as antitumour agents, since mitochondria are the main site of production of reactive oxygen species (ROS) and redox status is known to regulate the development and advancement of certain cancers. In this study we assessed a small library of novel flavonoids, then focussed on the lead compound, second-generation analogue OncamexTM, its mechanism of action and structure-activity relationships as an anti-proliferative agent. Methods: With this aim, we studied the effect of OncamexTM in a panel of 7 breast cancer cell lines using proliferation, cytotoxicity and apoptosis assays. The redox properties and mitochondrial delivery of the drug were studied using cyclic voltammetry and fluorescence microscopy, respectively. The mechanism of action was further studied using western blotting, gene expression analysis and immunohistochemistry (IHC) of treated xenograft tissue from in vivo mice models. Results: Sulforhodamine B (SRB) proliferation assays demonstrated strong, anti-proliferative properties of OncamexTM, with IC50 values in the low micromolar range. Treatment for 8 h exerted concentration-dependent reduction in cell viability and induction of cytotoxicity and apoptosis, with increased caspase activation. Microarray analysis suggested that OncamexTM regulates changes in cell cycle and apoptosis at gene expression level. Fluorescence microscopy was used to investigate mitochondrial targeting and ROS regulation in treated cells. OncamexTM was found to induce production of superoxide at concentrations which exerted anti-proliferative effects. Initial in vivo studies in mice implanted with a MDA-MB-231 breast cancer xenograft showed that OncamexTM inhibited tumour growth, reducing tissue viability and Ki-67 proliferation, with no overall systemic toxicity. Conclusions: OncamexTM is a novel flavonoid capable of specific delivery to the mitochondria and induction of ROS production. We have shown its antitumor activity in preclinical models of breast cancer, both in vitro and in initial in vivo models, where tumour growth was arrested without inducing toxicity, support the potential of this novel drug for its continued development as an anticancer agent.

Project description:BackgroundThe transfer of whole mitochondria that occurs during cell contact has been found to support cancer progression. However, the regulatory role of mitochondria alone is difficult to elucidate due to the complex microenvironment. Currently, mitochondrial transplantation is an available approach for restoring mitochondrial function in mitochondrial diseases but remains unclear in breast cancer. Herein, effects of mitochondrial transplantation via different approaches in breast cancer were investigated.MethodsWhole mitochondria (approximately 10.5 μg/ml) were transported into MCF-7 breast cancer cells via passive uptake or Pep-1-mediated delivery. Fresh mitochondria isolated from homeoplasmic 143B osteosarcoma cybrids containing mitochondrial DNA (mtDNA) derived from health individuals (Mito) or mtDNA with the A8344G mutation (Mito8344) were conjugated with cell-penetrating peptide Pep-1 (P-Mito) or not conjugated prior to cell co-culture. Before isolation, mitochondria were stained with MitoTracker dye as the tracking label. After 3 days of treatment, cell viability, proliferation, oxidative stress, drug sensitivity to Doxorubicin/Paclitaxel and mitochondrial function were assessed.ResultsCompared with P-Mito, a small portion of Mito adhered to the cell membrane, and this was accompanied by a slightly lower fluorescent signal by foreign mitochondria in MCF-7 cells. Both transplantations induced cell apoptosis by increasing the nuclear translocation of apoptosis-inducing factor; inhibited cell growth and decreased oxidative stress in MCF-7 cells; and increased the cellular susceptibility of both the MCF-7 and MDA-MB-231 cell lines to Doxorubicin and Paclitaxel. Mitochondrial transplantation also consistently decreased Drp-1, which resulted in an enhancement of the tubular mitochondrial network, but a distinct machinery through the increase of parkin and mitochondrial fusion proteins was observed in the Mito and P-Mito groups, respectively. Furthermore, although there were no differences in energy metabolism after transplantation of normal mitochondria, metabolism was switched to the energetic and glycolytic phenotypes when the mitochondria were replaced with dysfunctional mitochondria, namely, Mito8344 and P-Mito8344, due to dramatically induced glycolysis and reduced mitochondrial respiration, respectively. Consequently, transplant-induced growth inhibition was abolished, and cell growth in the Mito8344 group was even higher than that in the control group.ConclusionThis study reveals the antitumour potential of mitochondrial transplantation in breast cancer via distinct regulation of mitochondrial function.

Project description:Metastatic disease remains one of the most urgent clinical challenges accounting for over 90% of cancer-related deaths. Yet, the identification of novel therapeutic targets to fight or prevent metastatic disease has been hampered by the limited availability of clinically relevant mouse models of metastasis formation. To address this caveat, we developed a novel preclinical mouse model of spontaneous metastatic breast cancer that recapitulates the key biological events of the metastatic cascade and mimics the clinical course of metastatic disease in humans. Exploiting the conditional K14cre;CdhF/F;Trp53F/F mouse model of de novo mammary tumor formation, we orthotopically transplanted K14cre;CdhF/F;Trp53F/F derived mouse invasive lobular carcinoma (mILC) fragments into mammary glands of wild-type syngeneic hosts. Once recipient mammary tumors were established, we mimicked the clinical setting and performed a mastectomy. Following surgery, recipient mice eventually succumbed to wide-spread clinically overt metastatic disease in lymph nodes, lungs and gastrointestinal tract. Using aCGH analyses, we explored the relationship between the genomic profiles of mammary donor tumors and paired recipient outgrowths and observed a strong correlation, indicating that the genomic profile of the parental K14cre;CdhF/F;Trp53F/F mILC is highly conserved in recipient mammary tumors. To investigate the genomic relationship between recipient mammary tumors and their metastases, we examined the correlation structure of genomic profiles derived from paired sets of primary tumors and metastases. Genomic profiles of clonally-related recipient mammary tumors were highly conserved in local and distant metastases, indicating that few genomic alterations occur during transition from a primary tumor to a distant site. To more thoroughly examine potential site-specific genomic alterations, we constructed so-called ‘delta-profiles’ by calculating the difference between the genomic profile of a recipient mammary tumor and its paired lymph node- and lung metastasis. Site-specific recurrent alterations were not observed in lymph node nor lung metastases. Taken together, these data show that genomic profiles of metastases are highly similar to those of parental recipient tumors and that, if changes occurred, they did not recur in different independent samples. We performed aCGH analyses on DNA isolated from K14cre;Cdh-/-;Trp53-/- derived donor mILCs (n=3) and their recipient mammary tumor outgrowths (n=10). Furthermore, we also analyzed genomic profiles derived from lung (n=10), tumor-draining (n=7) and distant lymph node metastases (n=5) isolated from the same recipient mice. DNA from each of these samples was hybridized against related donor splenic DNA.

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Antitumour activity of the novel flavonoid Oncamex in preclinical breast cancer models.

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Antitumour activity of the novel flavonoid Oncamex in preclinical breast cancer models.

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