scholarly journals Dynamic Control of Mitochondrial Ca2+ Levels as a Survival Strategy of Cancer Cells

2021 ◽  
Vol 9 ◽  
Author(s):  
Corina T. Madreiter-Sokolowski ◽  
Benjamin Gottschalk ◽  
Armin A. Sokolowski ◽  
Roland Malli ◽  
Wolfgang F. Graier
Keyword(s):  
Cell Death ◽  
Cancer Cells ◽  
Cancer Cell ◽  
Uncoupling Protein ◽  
Expression Patterns ◽  
Prostate Adenocarcinoma ◽  
Invasive Cancer ◽  
Fine Tuning ◽  
Human Breast ◽  
Interaction Sites

Cancer cells have increased energy requirements due to their enhanced proliferation activity. This energy demand is, among others, met by mitochondrial ATP production. Since the second messenger Ca2+ maintains the activity of Krebs cycle dehydrogenases that fuel mitochondrial respiration, proper mitochondrial Ca2+ uptake is crucial for a cancer cell survival. However, a mitochondrial Ca2+ overload induces mitochondrial dysfunction and, ultimately, apoptotic cell death. Because of the vital importance of balancing mitochondrial Ca2+ levels, a highly sophisticated machinery of multiple proteins manages mitochondrial Ca2+ homeostasis. Notably, mitochondria sequester Ca2+ preferentially at the interaction sites between mitochondria and the endoplasmic reticulum (ER), the largest internal Ca2+ store, thus, pointing to mitochondrial-associated membranes (MAMs) as crucial hubs between cancer prosperity and cell death. To investigate potential regulatory mechanisms of the mitochondrial Ca2+ uptake routes in cancer cells, we modulated mitochondria–ER tethering and the expression of UCP2 and analyzed mitochondrial Ca2+ homeostasis under the various conditions. Hence, the expression of contributors to mitochondrial Ca2+ regulation machinery was quantified by qRT-PCR. We further used data from The Cancer Genome Atlas (TCGA) to correlate these in vitro findings with expression patterns in human breast invasive cancer and human prostate adenocarcinoma. ER-mitochondrial linkage was found to support a mitochondrial Ca2+ uptake route dependent on uncoupling protein 2 (UCP2) in cancer cells. Notably, combined overexpression of Rab32, a protein kinase A-anchoring protein fostering the ER-mitochondrial tethering, and UCP2 caused a significant drop in cancer cells' viability. Artificially enhanced ER-mitochondrial tethering further initiated a sudden decline in the expression of UCP2, probably as an adaptive response to avoid mitochondrial Ca2+ overload. Besides, TCGA analysis revealed an inverse expression correlation between proteins stabilizing mitochondrial-ER linkage and UCP2 in tissues of human breast invasive cancer and prostate adenocarcinoma. Based on these results, we assume that cancer cells successfully manage mitochondrial Ca2+ uptake to stimulate Ca2+-dependent mitochondrial metabolism while avoiding Ca2+-triggered cell death by fine-tuning ER-mitochondrial tethering and the expression of UCP2 in an inversed manner. Disruption of this equilibrium yields cancer cell death and may serve as a treatment strategy to specifically kill cancer cells.

scholarly journals Fatty acid synthase (FASN) regulates the mitochondrial priming of cancer cells

2021 ◽  
Vol 12 (11) ◽  
Author(s):  
Barbara Schroeder ◽  
Travis Vander Steen ◽  
Ingrid Espinoza ◽  
Chandra M. Kurapaty Venkatapoorna ◽  
Zeng Hu ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Death ◽  
Fatty Acid ◽  
Cancer Cells ◽  
Cancer Cell ◽  
Breast Cancer Cells ◽  
Fatty Acid Synthase ◽  
Xenograft Model ◽  
Fine Tuning ◽  
Bh3 Mimetic

AbstractInhibitors of the lipogenic enzyme fatty acid synthase (FASN) have attracted much attention in the last decade as potential targeted cancer therapies. However, little is known about the molecular determinants of cancer cell sensitivity to FASN inhibitors (FASNis), which is a major roadblock to their therapeutic application. Here, we find that pharmacological starvation of endogenously produced FAs is a previously unrecognized metabolic stress that heightens mitochondrial apoptotic priming and favors cell death induction by BH3 mimetic inhibitors. Evaluation of the death decision circuits controlled by the BCL-2 family of proteins revealed that FASN inhibition is accompanied by the upregulation of the pro-death BH3-only proteins BIM, PUMA, and NOXA. Cell death triggered by FASN inhibition, which causally involves a palmitate/NADPH-related redox imbalance, is markedly diminished by concurrent loss of BIM or PUMA, suggesting that FASN activity controls cancer cell survival by fine-tuning the BH3 only proteins-dependent mitochondrial threshold for apoptosis. FASN inhibition results in a heightened mitochondrial apoptosis priming, shifting cells toward a primed-for-death state “addicted” to the anti-apoptotic protein BCL-2. Accordingly, co-administration of a FASNi synergistically augments the apoptosis-inducing activity of the dual BCL-XL/BCL-2 inhibitor ABT-263 (navitoclax) and the BCL-2 specific BH3-mimetic ABT-199 (venetoclax). FASN inhibition, however, fails to sensitize breast cancer cells to MCL-1- and BCL-XL-selective inhibitors such as S63845 and A1331852. A human breast cancer xenograft model evidenced that oral administration of the only clinically available FASNi drastically sensitizes FASN-addicted breast tumors to ineffective single-agents navitoclax and venetoclax in vivo. In summary, a novel FASN-driven facet of the mitochondrial priming mechanistically links the redox-buffering mechanism of FASN activity to the intrinsic apoptotic threshold in breast cancer cells. Combining next-generation FASNis with BCL-2-specific BH3 mimetics that directly activate the apoptotic machinery might generate more potent and longer-lasting antitumor responses in a clinical setting.

Magneto Mitochondrial Dysfunction Mediated Cancer Cell Death Using Intracellular Magnetic Nano-Transducers

2021 ◽  
Author(s):  
Wooram Park ◽  
Seok-Jo Kim ◽  
Paul Cheresh ◽  
Jeanho Yun ◽  
Byeongdu Lee ◽  
...  
Keyword(s):  
Cell Death ◽  
Cancer Therapy ◽  
Mitochondrial Dysfunction ◽  
Cancer Cells ◽  
Cancer Cell ◽  
High Sensitivity ◽  
Intrinsic Pathway ◽  
Cancer Cell Death

Mitochondria are crucial regulators of the intrinsic pathway of cancer cell death. The high sensitivity of cancer cells to mitochondrial dysfunction offers opportunities for emerging targets in cancer therapy. Herein,...

Sulindac induces apoptotic cell death in susceptible human breast cancer cells through, at least in part, inhibition of IKKβ

APOPTOSIS ◽  
2009 ◽  
Vol 14 (7) ◽  
pp. 913-922 ◽  
Author(s):  
A-Mi Seo ◽  
Seung-Woo Hong ◽  
Jae-Sik Shin ◽  
In-Chul Park ◽  
Nam-Joo Hong ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Death ◽  
Cancer Cells ◽  
Human Breast Cancer ◽  
Breast Cancer Cells ◽  
Apoptotic Cell ◽  
Apoptotic Cell Death ◽  
Human Breast Cancer Cells ◽  
Human Breast

scholarly journals AKT but not MYC promotes reactive oxygen species-mediated cell death in oxidative culture

2019 ◽  
Author(s):  
Dongqing Zheng ◽  
Jonathan H. Sussman ◽  
Matthew P. Jeon ◽  
Sydney T. Parrish ◽  
Alireza Delfarah ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Reactive Oxygen Species ◽  
Cell Death ◽  
Oxidative Phosphorylation ◽  
Cancer Cells ◽  
Cell Lines ◽  
Cancer Cell ◽  
Breast Cancer Cell ◽  
Breast Cancer Cell Lines ◽  
Oxygen Species

ABSTRACTOncogenes can generate metabolic vulnerabilities in cancer cells. Here, we tested how AKT and MYC affect the ability of cells to shift between respiration and glycolysis. Using immortalized mammary epithelial cells, we discovered that constitutively active AKT but not MYC induced cell death in galactose culture, where cells must rely on oxidative phosphorylation for energy generation. However, the negative effects of AKT were short-lived, and AKT-expressing cells recommenced growth after ~15 days in galactose. To identify the mechanisms regulating AKT-mediated cell death, we used metabolomics and found that AKT cells dying in galactose upregulated glutathione metabolism. Next, using proteomics, we discovered that AKT-expressing cells dying in galactose upregulated nonsense-mediated mRNA decay, a marker of sensitivity to oxidative stress. We therefore measured levels of reactive oxygen species (ROS) and discovered that galactose induced ROS in cells expressing AKT but not MYC. Additionally, ROS were required for the galactose-induced death of AKT-expressing cells. We then tested whether these findings could be replicated in breast cancer cell lines with constitutively active AKT signaling. Indeed, we found that galactose induced rapid cell death in breast cancer cell lines and that ROS were required for galactose-induced cell death. Together, our results demonstrate that AKT but not MYC induces a metabolic vulnerability in cancer cells, namely the restricted flexibility to use oxidative phosphorylation.ImplicationsThe discovery that AKT but not MYC restricts the ability to utilize oxidative phosphorylation highlights that therapeutics targeting tumor metabolism must be tailored to the individual genetic profile of tumors.

scholarly journals ERβ-induced MFN2 inhibits the migration and invasiveness of breast cancer cells by inhibiting the P-AKT signaling pathway

2020 ◽  
Author(s):  
Mengyu Wei ◽  
Jun Hao ◽  
Xiaomei Liao ◽  
Yinfeng Liu ◽  
Ruihuan Fu ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Cancer Cell ◽  
Breast Cancer Cell ◽  
Breast Cancer Cells ◽  
Akt Pathway ◽  
Cancer Cell Migration ◽  
Breast Cancer Patients ◽  
Human Breast ◽  
Mcf 7

Abstract Background Mitofusin 2 (MFN2) is localized on the outer membrane of mitochondria and is closely related to the migration of malignant tumor cells. Estrogen receptor β (ERβ) plays an anticancer role in breast cancer. Our previous experiments showed that ERβ can induce MFN2 expression, which then inhibits breast cancer cell migration. However, the exact mechanism by which ERβ-induced MFN2 inhibits breast cancer cell migration is unknown. Methods In this study, immunohistochemistry was first used to detect the expression of MFN2 in breast cancer tissues, and its relationship with the clinicopathological characteristics and prognosis of breast cancer patients was analyzed. MCF-7 and MDA-MB-231 cells were transfected with ERβ and MFN2 knockdown or expression plasmids. Western blot was used to detect the effects of ERβ on MFN2 and MFN2 on P-AKT473 and MMP2; the P-AKT pathway inhibitor LY294002 was administered to cells transfected with MFN2 knockdown plasmids, Western blot, immunocytofluorescence, and a wound healing assay revealed the effect of MFN2 on its downstream signaling pathway and the migration of breast cancer cells. Results This study found that the expression of MFN2 is related to the molecular type and prognosis of breast cancer patients ( P <0.05). The positive expression rate of MFN2 in triple-negative breast cancer was significantly lower than that in the HER2 + and luminal types. However, MFN2 expression was unrelated to age, tumor size, lymph node metastasis, TNM stage, histological type and grade ( P >0.05); ERβ positively regulated MFN2 expression and reduced the migration of both MCF-7 and MDA-MB-231 cells, while MFN2 knockdown increased the expression of P-AKT473 and MMP2. In contrast, the overexpression of MFN2 inhibited the expression of P-AKT473 and MMP2. These results showed that in MFN2 knockdown cells treated with LY294002, P-AKT473 and MMP2 expression levels were reversed. The reversal of P-AKT473 and MMP2 expression levels inhibits the invasiveness of human breast cancer cells. Conclusion MFN2 is related to the molecular subtype and prognosis of breast cancer. In human breast cancer MCF-7 and MDA-MB-231 cells, ERβ-induced MFN2 can inhibit the P-AKT pathway, which inhibits the invasiveness and migration of both breast cancer cell lines.

scholarly journals Hydrogen Phosphate Selectively Induces MDA-MB-231 Breast Cancer Cell Death in vitro

2021 ◽  
Author(s):  
Aya Shanti ◽  
Kenana Al Adem ◽  
Cesare Stefanini ◽  
Sungmun Lee
Keyword(s):  
Breast Cancer ◽  
Cell Death ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Dihydrogen Phosphate ◽  
Human Breast ◽  
Hydrogen Phosphate ◽  
Cancer Cell Death ◽  
Phosphate Ions

Abstract Phosphate ions are the most abundant anions inside the cells, and they are increasingly gaining attention as key modulators of cellular function and gene expression. However, little is known about the effect of inorganic phosphate ions on cancer cells, particularly breast cancer cells. Here, we investigated the toxicity of different phosphate compounds to triple-negative human breast cancer cells (MDA-MB-231) and compared it to that of human monocytes (THP-1). We found that, unlike dihydrogen phosphate (H2PO4−), hydrogen phosphate (HPO42−) at 20 mM or lower concentrations induced breast cancer (MDA-MB-231) cell death more than immune (THP-1) cell death. We correlate this effect to the fact that phosphate in the form of HPO42− raises pH levels to alkaline levels which are not optimum for transport of phosphate into cancer cells. The results in this study highlight the importance of further exploring hydrogen phosphate (HPO42−) as a potential therapeutic for the treatment of breast cancer.

Sign in / Sign up

Export Citation Format

Share Document