Abstract 6353: Metabolic changes in the spleen and pancreas induced by PDAC xenografts with or without glutamine transporter downregulation
Authors: Sharma Raj Kumar , Bharti Santosh Kumar , Krishnamachary Balaji , Mironchik Yelena , Winnard Paul , Penet Marie-France , Bhujwalla Zaver M. 
Published: June 2022

Introduction: Our ongoing studies are focused on characterizing metabolic changes induced in the organs of mice with cachexia-inducing Pa04C human pancreatic cancer xenografts. Because pancreatic cancer cells are glutamine dependent [1], we downregulated the glutamine transporter SLC1A5 in Pa04C cells to determine if metabolic changes induced in the spleen and pancreas by Pa04C tumors were normalized when SLC1A5 was downregulated in these tumors. Metabolic patterns were characterized using high-resolution quantitative 1H magnetic resonance spectroscopy (MRS) of spleen and pancreas tissue obtained from normal mice and mice with Pa04C tumors and mice with Pa04C tumors with SLC1A5 downregulated.

Method: Patient derived cachexia-inducing Pa04C pancreatic cancer cells were lentivirally transduced to express shRNA to stably downregulate SLC1A5. Mice were euthanized once tumors were ~500 mm3, the spleen and pancreas were excised and snap frozen. Snap frozen spleen (normal n= 5, Pa04C n= 11, Pa04C_SLC1A5 n= 10) and pancreas (normal n= 4, Pa04C n= 16, Pa04C_SLC1A5 n= 10) tissue samples were pulverized for dual phase extraction. The aqueous phase was used for 1H MRS analysis. Topspin 3.5 software was used for data processing and analyses.

Results and Discussion: Significant downregulation of SLC1A5 mRNA and protein was confirmed in Pa04C_SLC1A5 cells and tumors. SLC1A5 downregulation resulted in significant growth delay and attenuation of weight loss. A comparison of normal mice vs empty vector/wild type tumor (EV/WT) bearing mice identified significant changes in succinate, aspartate and fumarate in the spleen, lactate, acetate, pyruvate, methionine, asparagine, creatine, choline phosphocholine, uracil, histidine and phenylalanine in the pancreas, with leucine, isoleucine, valine, alanine, glutamate, glutamine, glutathione, glycerophosphocholine, glycine, glucose and tyrosine commonly altered in the spleen and pancreas. A comparison of normal vs Pa04C_ SLC1A5 tumor bearing mice identified similar metabolic changes in the spleen and pancreas but these were reduced. Fumarate did not change in the spleen, and of the metabolic changes common to spleen and pancreas, glutamine did not change when tumor SLC1A5 was downregulated. Metabolite changes induced only in the pancreas were also similar to normal vs EV/WT with the exception of a change in glutamine with SLC1A5 downregulation and no change in lactate. Our data highlight the profound metabolic changes in spleen and pancreas metabolism that occur with growth of a cachexia-inducing pancreatic cancer xenograft, and the impact on these metabolic patterns as a result of downregulating the glutamine transporter in these cancer cells. The metabolic patterns identified in the spleen and pancreas may provide novel targets to reduce the morbidity from cachexia.

Reference: 1. Son J et al, Nature. 2013;496(7443):101-5.

Citation Format: Raj Kumar Sharma, Santosh Kumar Bharti, Balaji Krishnamachary, Yelena Mironchik, Paul Winnard Jr., Marie-France Penet, Zaver M. Bhujwalla. Metabolic changes in the spleen and pancreas induced by PDAC xenografts with or without glutamine transporter downregulation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6353.