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Browsing by Author "Mohallem, Rodrigo"
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Item Alkynyl nicotinamides show antileukemic activity in drug-resistant acute myeloid leukemia(The American Society for Clinical Investigation, 2024-06-17) Ramdas, Baskar; Dayal, Neetu; Pandey, Ruchi; Larocque, Elizabeth; Kanumuri, Rahul; Pasupuleti, Santhosh Kumar; Liu, Sheng; Kanellopoulou, Chrysi; Chu, Elizabeth Fei Yin; Mohallem, Rodrigo; Virani, Saniya; Chopra, Gaurav; Aryal, Uma K.; Lapidus, Rena; Wan, Jun; Emadi, Ashkan; Haneline, Laura S.; Holtsberg, Frederick W.; Aman, M. Javad; Sintim, Herman O.; Kapur, Reuben; Pediatrics, School of MedicineActivating mutations of FLT3 contribute to deregulated hematopoietic stem and progenitor cell (HSC/Ps) growth and survival in patients with acute myeloid leukemia (AML), leading to poor overall survival. AML patients treated with investigational drugs targeting mutant FLT3, including Quizartinib and Crenolanib, develop resistance to these drugs. Development of resistance is largely due to acquisition of cooccurring mutations and activation of additional survival pathways, as well as emergence of additional FLT3 mutations. Despite the high prevalence of FLT3 mutations and their clinical significance in AML, there are few targeted therapeutic options available. We have identified 2 novel nicotinamide-based FLT3 inhibitors (HSN608 and HSN748) that target FLT3 mutations at subnanomolar concentrations and are potently effective against drug-resistant secondary mutations of FLT3. These compounds show antileukemic activity against FLT3ITD in drug-resistant AML, relapsed/refractory AML, and in AML bearing a combination of epigenetic mutations of TET2 along with FLT3ITD. We demonstrate that HSN748 outperformed the FDA-approved FLT3 inhibitor Gilteritinib in terms of inhibitory activity against FLT3ITD in vivo.Item Sulfotransferase 1C2 Increases Mitochondrial Respiration by Converting Mitochondrial Membrane Cholesterol to Cholesterol Sulfate(American Chemical Society, 2024) Kolb, Alexander J.; Corridon, Peter; Ullah, Mahbub; Pfaffenberger, Zechariah J.; Xu, Wei Min; Winfree, Seth; Sandoval, Ruben H.; Hato, Takeshi; Witzmann, Frank A.; Mohallem, Rodrigo; Franco, Jackeline; Aryal, Uma K.; Atkinson, Simon J.; Basile, David P.; Bacallao, Robert L.; Biology, School of ScienceHypothesis: In this communication, we test the hypothesis that sulfotransferase 1C2 (SULT1C2, UniProt accession no. Q9WUW8) can modulate mitochondrial respiration by increasing state-III respiration. Methods and results: Using freshly isolated mitochondria, the addition of SULT1C2 and 3-phosphoadenosine 5 phosphosulfate (PAPS) results in an increased maximal respiratory capacity in response to the addition of succinate, ADP, and rotenone. Lipidomics and thin-layer chromatography of mitochondria treated with SULT1C2 and PAPS showed an increase in the level of cholesterol sulfate. Notably, adding cholesterol sulfate at nanomolar concentration to freshly isolated mitochondria also increases maximal respiratory capacity. In vivo studies utilizing gene delivery of SULT1C2 expression plasmids to kidneys result in increased mitochondrial membrane potential and confer resistance to ischemia/reperfusion injury. Mitochondria isolated from gene-transduced kidneys have elevated state-III respiration as compared with controls, thereby recapitulating results obtained with mitochondrial fractions treated with SULT1C2 and PAPS. Conclusion: SULT1C2 increases mitochondrial respiratory capacity by modifying cholesterol, resulting in increased membrane potential and maximal respiratory capacity. This finding uncovers a unique role of SULT1C2 in cellular physiology and extends the role of sulfotransferases in modulating cellular metabolism.