Calcium Signalling; Cancer; Calcium regulated mitochondrial SLCs; Development Transporter Inhibitors; Store-operated calcium entry; Structures of Mitochondrial Transporters; ER-Mitochondrial Membrane Contact Sites; Regulation of Energy Metabolism; SLC Solute Carriers
Schild Achille, Bhardwaj Rajesh, Wenger Nicolas, Tscherrig Dominic, Kandasamy Palanivel, Dernič Jan, Baur Roland, Peinelt Christine, Hediger Matthias A., Lochner Martin (2020), Synthesis and Pharmacological Characterization of 2-Aminoethyl Diphenylborinate (2-APB) Derivatives for Inhibition of Store-Operated Calcium Entry (SOCE) in MDA-MB-231 Breast Cancer Cells, in International Journal of Molecular Sciences
, 21(16), 5604-5604.
Cunha M.R., Bhardwaj R., Carrel A.L., Lindinger S., Romanin C., Parise-Filho R., Hediger M.A., Reymond J-L (2020), Natural product inspired optimization of a selective TRPV6 calcium channel inhibitor., in RSC Med. Chem
, 2020(11), 1032-1040.
Bhardwaj Rajesh, AugustynekBartlomiej, Ercan-HerbstEbru, KandasamyPalanivel, SeedorfMatthias, PeineltChristine, HedigerMatthias A. (2020), Ca2+/Calmodulin Binding to STIM1 Hydrophobic Residues Facilitates Slow Ca2+-Dependent Inactivation of the Orai1 Channel, in Cellular Physiology and Biochemistry
, 54(2), 252-270.
Pereira Gustavo José Vasco, Tavares Maurício Temotheo, Azevedo Ricardo Alexandre, Martins Barbara Behr, Cunha Micael Rodrigues, Bhardwaj Rajesh, Cury Yara, Zambelli Vanessa Olzon, Barbosa Euzébio Guimarães, Hediger Matthias A., Parise-Filho Roberto (2019), Capsaicin-like analogue induced selective apoptosis in A2058 melanoma cells: Design, synthesis and molecular modeling, in Bioorganic & Medicinal Chemistry
, 27(13), 2893-2904.
Intracellular Ca2+ signals control an array of physiological functions including gene expression, cell proliferation, muscle contraction and fertilization and are central to regulating cell death and survival. These Ca2+ signals arise from the release of Ca2+ from endoplasmic reticulum (ER) stores, followed by activation of a refilling pathway known as store-operated Ca2+ entry (SOCE) and/or other Ca2+ influx routes through the plasma membrane (PM), such as epithelial Ca2+ channel TRPV6. The spatiotemporal patterning of Ca2+ signals and the localization of Ca2+-dependent effectors ensure their specific translation into physiological responses. The highly dynamic nature of ER and membrane tethering proteins allows ER to establish transient physical contacts with PM, mitochondria and other organelles and thereby shape the spatiotemporal patterns of Ca2+ signals. The release of Ca2+ at the membrane contact sites (MCS) enable the formation of microdomains of high Ca2+ concentrations also called Ca2+ hotspots between these closely apposed organellar membranes, for example ER-mitochondria (ER-Mt) contact sites. Ca2+ hotspots on the mitochondrial surface facilitate the function of mitochondrial Ca2+ uniporter (MCU) to take up Ca2+ despite its low affinity to Ca2+. Ca2+ signaling is linked to bioenergetic homeostasis, which ensures that energy supply has the capacity to meet energy demand. A rise in intracellular Ca2+ concentration signals an increased cellular energy demand, which in part is also required for the efficient functioning of Ca2+ ATPases crucial for maintaining Ca2+ homeostasis. Despite significant progress in our understanding of how Ca2+ signaling is coupled to energy metabolism, there are still many crucial missing links that we aim to address in this grant application: 1. The role of ER-Mt contact sites and the MCU complex in promoting bioenergetics has been established, because a rise in mitochondrial matrix Ca2+ concentration drives the allosteric activation of the rate-limiting enzymes of the tricarboxylic acid cycle. In addition, several SLC mitochondrial solute carriers are regulated by cytosolic Ca2+ levels and are likely to be involved in this process. It is, however, unknown whether Ca2+-regulated mitochondrial solute carriers (mSLCsCa) are localized in ER-Mt contact sites and whether the bioenergetic function of mSLCsCa is directly modulated by the dynamics of ER-Mt contact sites (WP1, WP2 and WP3). 2. SOCE has also been implicated in regulating mitochondrial bioenergetics. However, the mechanistic basis and the molecular links other than MCU are not clear (WP2 and WP3). 3. It is intriguing to hypothesize that subplasmalemmal mitochondria being in close vicinity to TRPV6 channels at the PM augment bioenergetics through a direct impact on MCU and mSLCsCa, which could explain the role of TRPV6 in prostate and breast cancer progression (WP3). 4. It is largely unknown whether mSLCsCa contribute in a feedback mechanism to the regulation of MCS and the associated Ca2+ flow, thereby affecting Ca2+ homeostasis (WP4). 5. The SOCE machinery and the ER-to-mitochondria Ca2+ transferring machinery are remodeled in several cancer types (partly by the role of oncogenes), with serious consequences on biosynthetic pathways. However, how oncogene and tumor suppressor mutations affect the expression and function of mSLCsCa and whether altered Ca2+ flow across MCS is also linked to dysregulation of mSLCsCa remains elusive (WP5). 6. Structural details on the conformational changes induced by Ca2+ in several mSLCsCa are either entirely missing or partly understood and these studies are essential to understand the Ca2+ regulation mechanism of mSLCsCa-mediated transport (WP6). Thus, the overall purpose of this proposal is to investigate the role of Ca2+ flow across MCS in regulating the bioenergetic function of mSLCsCa in cell physiology and how this contributes to the metabolic reprogramming in cancer. To achieve these goals, we have assembled an interdisciplinary research team that integrates state-of-the-art structural biology, membrane biophysics, synthetic chemistry, super-resolution imaging, electron microscopy and next-generation cancer tissue microarray analysis.