Development of a methodology for in vivo follow-up of hepatocellular carcinoma in hepatocyte specific Trim24-null mice treated with myo-inositol trispyrophosphate.

Mihaela Ignat,Cherif Youssef Akladios,Jacques Marescaux,Marius Teletin,Pierre Marc Aprahamian,Konstantin Khetchoumian,Véronique Lindner,Didier Muttter

doi:10.1186/s13046-016-0434-8

Abstract

BackgroundGenetically induced hepatocellular carcinoma (HCC) models are generally used to investigate carcinogenesis pathways, but very few attempts were made to valorize them for pharmacological testing. This study describes a micro-computed tomography (micro-CT) - based methodology for the diagnostic and lifelong follow-up of HCC in the hepatocyte-specific Trim24-null mouse line. Myo-inositol trispyrophosphate (ITPP) was tested as anti-cancer drug.MethodsPartial hepatectomy was performed in 2 months-old Trim24-null mice, in order to accelerate the carcinogenesis process. HCC diagnosis was obtained by micro-CT scan with double contrast agent: 10 μl/g Fenestra™ LC was injected intraperitoneally 6 h prior to imaging and 10 μl/g Fenestra™ VC was injected intravenously 15 min prior to imaging. Twenty three hepatocyte-specific Trim24-null mice were considered for ITPP testing (3 mg/g/week intraperitoneally during 10 months in 12 mice, versus 11 controls). Lifelong follow-up was performed using micro-CT. Comparative analysis was performed using unpaired t test with Welch correction and survival curves were compared by log-rank test. Gene expression analysis was performed using the RT q-PCR technique.ResultsDouble contrast micro-CT scan allowed HCC diagnosis as hypodense, isodense or hyperdense nodules. Positive predictive value was 81.3 %. Negative predictive value was 83.3 %. Tumor growth could be objectified by micro-CT scan before the ITPP treatment was started, and at 3 and 9 months follow-up. Significant progression of tumor volume was demonstrated in the both groups, with no difference between groups (p > 0.05). In the ITPP group, a mild decrease in tumor doubling time was first observed (31.9 +/− 12 days, p > 0.05) followed by a significant increase (59.8 +/− 18.3 days, p = 0.008). However, tumor doubling time was not different between groups (p > 0.05). Median survival after treatment initiation was 223 days (controls) versus 296 days (ITPP group, p = 0.0027). HIF1α, VEGF, glutamine synthase, osteopontin expression levels were not significantly modified at the end of follow-up. In the ITPP group, the p53 expression profile was inversed as compared to the control group, higher in non-tumor livers than in tumors.ConclusionITPP treatment allowed for a two-month survival improvement, with better tolerance of tumor burden and apoptosis increase in non-tumor, pathological livers.Electronic supplementary materialThe online version of this article (doi:10.1186/s13046-016-0434-8) contains supplementary material, which is available to authorized users.

Highlights

Induced hepatocellular carcinoma (HCC) models are generally used to investigate carcinogenesis pathways, but very few attempts were made to valorize them for pharmacological testing
Partial hepatectomy Based on the principle of partial hepatectomy (PH) as promoter of liver carcinogenesis [16], a two-third partial hepatectomy was performed in Trim24L2/L2Alb-Cre males at the age of 2 months
Acceleration of hepatocarcinogenesis process by means of partial hepatectomy (PH) Early and medium-term consequences of PH were evaluated by relative liver mass measurements, proliferation and apoptosis levels

Summary

Introduction

Induced hepatocellular carcinoma (HCC) models are generally used to investigate carcinogenesis pathways, but very few attempts were made to valorize them for pharmacological testing. Small animal models are often the only available means of testing the safety, potency, and efficacy of new anticancer agents prior to clinical trials. Several types of mouse models of HCC are available, depending on tumor-inducing mechanisms. The most frequently used models are xenograft models. They are easy to obtain and follow up, with a rapid growth rate, but their relevance is limited, as the resemblance between xenograft tumors and human HCC is rather poor [4]. There are significant differences in tumor growth inhibition between HCC cell lines [5]

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