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BACKGROUND Most cancer cells are more glycolytic even under aerobic conditions compared with their normal counterparts. Recent evidence of tumor cell metabolism, however, shows that some tumors also increase mitochondrial oxidative phosphorylation (ox-phos) at some disease states during progression and/or development of drug resistance. Our data show that anti-androgen enzalutamide (ENZA) resistant prostate cancer (PCa) cells use more mitochondrial metabolism leading to higher ox-phos as compared to the ENZA-sensitive cells and can become vulnerable to mitochondrial metabolism targeted therapies. METHODS Seahorse assay, mass spectrometry and high resolution fluorescence confocal microscopy coupled with image analysis has been used to compare mitochondrial metabolism in ENZA-treated and -untreated anti-androgen-sensitive LNCaP and -resistant C4-2, CWR22ν1, and PCa2b cells. Ex vivo fluorescence microscopy and image analysis has been standardized to monitor mitochondrial electron transport (ETS) activity that likely increases ox-phos in circulating tumor cells (CTCs) isolated fom patients undergoing AR-targeted therapies. RESULTS Our data show that PCa cells that are resistant to anti-androgen ENZA switch from glycolysis to ox-phos leading to an increased ETS activity. ENZA pretreated cells are more vulnerable to ETS component complex I inhibitor IACS-010759 (IACS) and mitochondrial glutaminase inhibitor CB-839 that reduces glutamate supply to tricarboxylic acid cycle. CTCs isolated from 6 of 20 patient blood samples showed relatively higher ETS activity than the rest of the patients. All six patients have developed ENZA resistance within less than 6 months of the sample collection. CONCLUSION The enhanced growth inhibitory effects of mitochondrial metabolic inhibitors IACS and CB-839 in ENZA pretreated PCa cells provides a rationale for designing a drug combination trial. Patients can be selected for such trials by monitoring the mitochondrial ETS activities in their CTCs to maximize success.

Background: Most cancer cells depend more on glycolysis for their energy need compared with their normal counterparts incubated under identical condition. In addition to glycolysis, tumor cells also engage mitochondrial ox-phos to support growth. Here, we show that PCa cells surviving under anti-androgen enzalutamide (ENZA) treatment switch from glycolysis to ox-phos for their energy need and are more vulnerable to mitochondria-targeted metabolic inhibitors. We have also standardized a high-resolution quantitative fluorescence microscopic method to detect this metabolic switch in patient circulating tumor cells (CTCs). Methods: Seahorse assay has been used to compare mitochondrial metabolism in ENZA treated anti-androgen-sensitive LNCaP and -resistant C4-2 and PCa2b cells. The Seahorse data were supported by mass spectroscopic analysis of corresponding metabolites and metabolic fluxes. An ex vivo fluorescence staining for the CTC mitochondria with high ox-phos followed by high-resolution quantitative microscopic image analysis method has been standardized to follow such changes in cultured cells and patient CTCs. Results: Seahorse, mass spectroscopy and high-resolution microscopy of mitochondrial ox-phos showed that ENZA significantly decreases glycolysis and increases ox-phos in all surviving PCa cells within 24h of treatment. These cells are more vulnerable to treatment with mitochondrial ox-phos inhibitor IACS-010759 and a glutaminase inhibitor CB-839. High-resolution microscopic analysis of CTCs has thus far been performed in 18 patient blood samples. Six out of the 18 patients developed resistance to anti-androgen therapy within 0-6 months of sample collection. CTCs from all six patients showed a relatively higher average fluorescence due to high mitochondrial ox-phos as compared with the rest of the patients. Discussion: The data presented here may lead to informed combination therapy for selected PCa patients developing resistance to anti-androgen therapy for better clinical outcome. Citation Format: Hirak S. Basu, Nathaniel Wilganowski, Samantha Robertson, Sumankalai Ramachandran, Amado Zurita-Saavedra, Mark Titus, Evan Cohen, James Reuben, George Wilding. Metabolic switch from glycolysis to oxidative phosphorylation (ox-phos) provides survival advantage to anti-androgen-treated prostate cancer cells and make them vulnerable to mitochondrial metabolism inhibitors IACS-010759 and CB-839 [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4791.

Hepatic cancer is one of the most lethal cancers worldwide. Here, we report that the expression of Ca2+/calmodulin-dependent protein kinase kinase 2 (CaMKK2) is significantly up-regulated in hepatocellular carcinoma (HCC) and negatively correlated with HCC patient survival. The CaMKK2 protein is highly expressed in all eight hepatic cancer cell lines evaluated and is markedly up-regulated relative to normal primary hepatocytes. Loss of CaMKK2 function is sufficient to inhibit liver cancer cell growth, and the growth defect resulting from loss of CaMKK2 can be rescued by ectopic expression of wild-type CaMKK2 but not by kinase-inactive mutants. Cellular ablation of CaMKK2 using RNA interference yields a gene signature that correlates with improvement in HCC patient survival, and ablation or pharmacological inhibition of CaMKK2 with STO-609 impairs tumorigenicity of liver cancer cells in vivo. Moreover, CaMKK2 expression is up-regulated in a time-dependent manner in a carcinogen-induced HCC mouse model, and STO-609 treatment regresses hepatic tumor burden in this model. Mechanistically, CaMKK2 signals through Ca2+/calmodulin-dependent protein kinase 4 (CaMKIV) to control liver cancer cell growth. Further analysis revealed that CaMKK2 serves as a scaffold to assemble CaMKIV with key components of the mammalian target of rapamycin/ribosomal protein S6 kinase, 70 kDa, pathway and thereby stimulate protein synthesis through protein phosphorylation. Conclusion: The CaMKK2/CaMKIV relay is an upstream regulator of the oncogenic mammalian target of rapamycin/ribosomal protein S6 kinase, 70 kDa, pathway, and the importance of this CaMKK2/CaMKIV axis in HCC growth is confirmed by the potent growth inhibitory effects of genetically or pharmacologically decreasing CaMKK2 activity; collectively, these findings suggest that CaMKK2 and CaMKIV may represent potential targets for hepatic cancer. (Hepatology 2015;62:505–520

Fluorescence-guided surgery is an emerging imaging technique that can enhance the ability of surgeons to detect tumors when compared with visual observation. To facilitate characterization, fluorescently labeled probes have been dual-labeled with a radionuclide to enable cross-validation with nuclear imaging. In this study, we selected the somatostatin receptor imaging agent DOTATOC as the foundation for developing a dual-labeled analog. We hypothesized that a customized dual-labeling approach with a multimodality chelation (MMC) scaffold would minimize steric effects of dye conjugation and retain agonist properties. Methods: An MMC conjugate (MMC-TOC) was synthesized on solid-phase and compared with an analog prepared using conventional methods (DA-TOC). Both analogs were conjugated to IRDye 800 using copper-free click chemistry. The resulting compounds, MMC(IR800)-TOC and DA(IR800)-TOC, were labeled with Cu and 64Cu and tested in vitro in somatostatin receptor subtype 2-overexpressing HEK-293 cells to assess agonist properties, and in AR42J rat pancreatic cancer cells to determine receptor binding characteristics. Multimodality imaging was performed in AR42J xenografts. Results: Cu-MMC(IR800)-TOC demonstrated higher potency for cyclic adenosine monophosphate inhibition (half maximal effective concentration [EC50]: 0.21 ± 0.18 vs. 1.38 ± 0.54 nM) and receptor internalization (EC50: 41.9 ± 29.8 vs. 455 ± 299 nM) than Cu-DA(IR800)-TOC. Radioactive uptake studies showed that blocking with octreotide caused a dose-dependent reduction in 64Cu-MMC(IR800)-TOC uptake whereas 64Cu-DA(IR800)-TOC was not affected. In vivo studies revealed higher tumor uptake for 64Cu-MMC(IR800)-TOC than 64Cu-DA(IR800)-TOC (5.2 ± 0.2 vs. 3.6 ± 0.4 percentage injected dose per gram). In vivo blocking studies with octreotide reduced tumor uptake of 64Cu-MMC(IR800)-TOC by 66%. Excretion of 64Cu-MMC(IR800)-TOC was primarily through the liver and spleen whereas 64Cu-DA(IR800)-TOC was cleared through the kidneys. Ex vivo analysis at 24 h confirmed PET/CT data by showing near-infrared fluorescence signal in tumors and a tumor-to-muscle ratio of 5.3 ± 0.8 as determined by γ-counting. Conclusion: The findings demonstrate that drug design affected receptor pharmacology and suggest that the MMC scaffold is a useful tool for the development of dual-labeled imaging agents.

David R Powell,Jason P Gay,Melinda Smith,Nathaniel Wilganowski,Angela Harris,Autumn Holland,Maricela Reyes,Laura Kirkham,Laura L Kirkpatrick,Brian Zambrowicz,Gwenn Hansen,Kenneth A Platt,Isaac van Sligtenhorst,Zhi-Ming Ding,Urvi Desai Metabolism Research, Lexicon Pharmaceuticals, Inc., The Woodlands, TX, USA Abstract: Delta-5 desaturase (D5D) and delta-6 desaturase (D6D), encoded by fatty acid desaturase 1 (FADS1) and FADS2 genes, respectively, are enzymes in the synthetic pathways for w3, w6, and w9 polyunsaturated fatty acids (PUFAs). Although PUFAs appear to be involved in mammalian metabolic pathways, the physiologic effect of isolated D5D deficiency on these pathways is unclear. After generating >4,650 knockouts (KOs) of independent mouse genes and analyzing them in our high-throughput phenotypic screen, we found that Fads1 KO mice were among the leanest of 3,651 chow-fed KO lines analyzed for body composition and were among the most glucose tolerant of 2,489 high-fat-diet-fed KO lines analyzed by oral glucose tolerance test. In confirmatory studies, chow- or high-fat-diet-fed Fads1 KO mice were leaner than wild-type (WT) littermates; when data from multiple cohorts of adult mice were combined, body fat was 38% and 31% lower in Fads1 male and female KO mice, respectively. Fads1 KO mice also had lower glucose and insulin excursions during oral glucose tolerance tests along with lower fasting glucose, insulin, triglyceride, and total cholesterol levels. In additional studies using a vascular injury model, Fads1 KO mice had significantly decreased femoral artery intima/media ratios consistent with a decreased inflammatory response in their arterial wall. Based on this result, we bred Fads1 KO and WT mice onto an ApoE KO background and fed them a Western diet for 14weeks; in this atherogenic environment, aortic trees of Fads1 KO mice had 40% less atheromatous plaque compared to WT littermates. Importantly, PUFA levels measured in brain and liver phospholipid fractions of Fads1 KO mice were consistent with decreased D5D activity and normal D6D activity. The beneficial metabolic phenotype demonstrated in Fads1 KO mice suggests that selective D5D inhibitors may be useful in the treatment of human obesity, diabetes, and atherosclerotic cardiovascular disease. Keywords: delta-5 desaturase, delta-6 desaturase, obesity, diabetes, atherosclerosis

Introduction: The mechanism of prostate cancer (PCa) progression to the mostly lethal, metastatic, castrate-resistant stage (mCRPC) remains generally unknown. This prevents identifying patients likely to progress to mCRPC and designing new therapies for their treatment. A transcription factor JunD is overexpressed in PCa, but not in normal prostate epithelial cells. It complexes with androgen receptor (AR) to induce spermidine/spermine acetyl transferase (SSAT) [3]. SSAT initiates polyamine oxidation that generates copious amounts of reactive oxygen species (ROS) production in polyamine-rich PCa cells. ROS activate NF-κB. NF-κB can also induce SSAT and activate AR. This sets up a feed-forward loop for PCa growth at low androgen. Here, we present one mechanism of PCa progression to CRPC as well as its invasion and metastasis that may provide predictive biomarkers to identify patients with potentially lethal PCa at an early stage. Effects of an agent that can block both AR-JunD and AR-NF-κB interactions and prevent growth of PCa cells in vitro as well as in vivo xenografts will also be presented. Method: We have used a novel microscale device to separate invading from noninvading PCa cells ex vivo in a bone microenvironment. Immunocytochemistry (ICC), proteomic and metabolomic techniques have been employed to analyze the separated cells to understand the mechanism of invasion. Gaussia luciferase reconstitution assay has been used in a high-throughput screen (HTS) to identify inhibitors of AR-JunD and AR-NF-κB interactions. State-of-the-art in vitro cell growth assay along with in vivo pharmacokinetic (PK), maximum tolerated dose (MTD) and enzalutamide-resistant CRPC cell xenograft growth in nude mice are used to optimize the lead. Summary of Unpublished Results: Immunocytochemistry (ICC) data show that in cultured enzalutamide-resistant C4-2 and -sensitive LNCaP cells as well as in some patient PCa cells, more SSAT-positive cells are in the migratory than in the stationary section of the microscale device. Metabolomic analysis show a decrease in 3-phospho-glycerate levels in C4-2 cells, suggesting a decrease in GAPDH enzymatic activity that is related to an enhanced oxidation of GAPDH protein. Our published data of screening of 27,000+ compounds from two different chemical libraries detected a single compound that specifically inhibits both AR-JunD and AR-NF-κB2 (p52) interactions. We have synthesized several of its analogs. Lead analogs inhibit growth of AR-positive C4-2 and LNCaP cells, but have little effect on the growth of AR-negative PC-3 and SSAT-silent LNCaP siSSAT cells in culture. Co-immunoprecipitation (co-IP) assay shows its efficacy in inhibiting AR-JunD and AR-p52 interactions in LNCaP cells. It has been formulated in 25% ethanol:water and administered to nude mice orally. It is well tolerated at 50 mg/kg p.o. daily for more than 28 days and has a serum Cmax of ~ 3 μM within 30 minutes and a plasma t1/2 of ~1 h after a single oral dose of 100 mg/kg. Twenty-four hours after dosing it is found in the flank tumor (1.5 ng/mg tissue; ~450 nM) and in the prostate tissues (10 ng/mg tissue; ~3 μM) in addition to liver and kidney. Its effects on the growth of C4-2 xenografts in nude mice will be presented. Conclusion: A mechanism of PCa progression to CRPC and then to mCRPC provides a rational basis for targeted drug design that prevents PCa progression and metastasis. This should open up a new avenue of precision therapy of potentially lethal PCa at an early stage. Citation Format: Hirak Basu, Nathaniel Wilganowski, Jessica Lieblich, Grace Wu, Izabela Fokt, Sumankalai Ramachandran, Jiaquin Yu, Mark Titus, Waldemar Priebe, David J. Beebe, George Wilding. Small-molecule inhibitors targeting a specific metabolic pathway for precision therapy of advanced castrate-resistant prostate cancer [abstract]. In: Proceedings of the AACR Special Conference: Prostate Cancer: Advances in Basic, Translational, and Clinical Research; 2017 Dec 2-5; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(16 Suppl):Abstract nr B091.

After creating >4650 knockouts (KOs) of independent mouse genes, we screened them by high-throughput phenotyping and found that cannabinoid receptor 1 (Cnr1) KO mice had the same lean phenotype published by others. We asked if our KOs of DAG lipase a or b (Dagla or Daglb), which catalyze biosynthesis of the endocannabinoid (EC) 2-Arachidonoylglycerol (2-AG), or Napepld, which catalyzes biosynthesis of the EC anandamide, shared the lean phenotype of Cnr1 KO mice. We found that Dagla KO mice, but not Daglb or Napepld KO mice, were among the leanest of 3651 chow-fed KO lines screened. In confirmatory studies, chow- or high fat diet-fed Dagla and Cnr1 KO mice were leaner than wild type (WT) littermates; when data from multiple cohorts of adult mice were combined, body fat was 47% and 45% lower in Dagla and Cnr1 KO mice, respectively, relative to WT values. In contrast, neither Daglb nor Napepld KO mice were lean. Weanling Dagla KO mice ate less than WT mice and had body weight similar to pair-fed WT mice, and adult Dagla KO mice had normal activity and VO2 levels, similar to Cnr1 KO mice. Our Dagla and Cnr1 KO mice also had low fasting insulin, triglyceride and total cholesterol levels, and after a glucose challenge had normal glucose but very low insulin levels. Dagla and Cnr1 KO mice also showed similar responses to a battery of behavioral tests. These data suggest: 1) the lean phenotype of young Dagla and Cnr1 KO mice is mainly due to hypophagia; 2) in pathways where ECs signal through Cnr1 to regulate food intake and other metabolic and behavioral phenotypes observed in Cnr1 KO mice, Dagla alone provides the 2-AG that serves as the EC signal; and 3) small molecule Dagla inhibitors with a pharmacokinetic profile similar to that of Cnr1 inverse agonists are likely to mirror the ability of these Cnr1 inverse agonists to lower body weight and improve glycemic control in obese patients with type 2 diabetes, but may also induce undesirable neuropsychiatric side-effects.