Abstract 2807: Variations in glycolytic activity of HCC subtypes as monitored by in vivo h 13C MRI

Abstract

Abstract Hepatocellular carcinoma (HCC) is the 4th leading cause of cancer-related death worldwide. Despite therapeutic advancements, a significant proportion of patients progress, highlighting the need to improve diagnostic approaches to monitor therapy. Radiofrequency ablation (RFA), an accepted locoregional therapy for early HCC, can stimulate more aggressive tumor biology within under-treated or distant tumors. Increased glycolytic activity is a hallmark feature of cancer, but variations in metabolism and its link to tumor aggression can impact the sensitivity of HCC to therapies affecting these pathways. Tumor metabolic phenotypes can be characterized by hyperpolarized 13C MRI (h13C MRI), which can also be used to assess treatment response. In this study, we used orthotopic rat HCC models with two different cell lines N1S1 and MCA-RH7777, and analyzed their mRNA expression of glycolysis-related genes and in vivo glycolytic activity with h13C MRI. We then partially-treated tumors with radiofrequency ablation (RFA) and used h13C MRI to measure in vivo tumor metabolism before and 3 days after RFA to compare them to histologic and phenotypical measures of disease progression. N1S1 tumors grew only as single lesions, while MCA-RH7777 rapidly produced intra-hepatic and distal metastases. Glycolysis-related genes including HK2, HK3, PFKFB3, and MCT4 were highly expressed in N1S1, but not in MCA-RH7777, while GPT1 was highly expressed in MCA-RH7777 but not in N1S1. In vivo h13C MRI demonstrated significantly increased 13C lactate flux in N1S1 tumor compared to the background normal liver, while 13C lactate flux in MCA-RH7777 rat model did not, consistent with mRNA expression patterns. Tumor 13C lactate flux was significantly increased and 13C alanine flux was significantly decreased following partial RFA treatment to N1S1 tumors when compared to untreated tumors, which was associated with an increase in tumor Ki67 expression. However, no change was seen on h13C MRI between the RFA and control arms in MCA-RH7777 tumors, even though growth and total tumor burden progressed significantly more following RFA. In contrast to N1S1, there was also no difference between 13C lactate flux and 13C alanine flux within MCA-RH7777 tumors and the neighboring normal hepatic parenchyma, suggesting that glycolytic activity in these tumors did not drive RFA-stimulated progression. Targeting of glycolytic pathways as a potential therapy for HCC may therefore be limited to certain subtypes, and h13C MRI may be used to select for sensitivity. Citation Format: Qianhui Dou, Aaron K. Grant, Cody Callahan, Muneeb Ahmed, Leo L. Tsai. Variations in glycolytic activity of HCC subtypes as monitored by in vivo h 13C MRI [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2807.