Rapid induction of orthotopic hepatocellular carcinoma in immune-competent rats by non-invasive ultrasound-guided cells implantation

Abstract

BackgroundThe fact that prognoses remain poor in patients with advanced hepatocellular carcinoma highlights the demand for suitable animal models to facilitate the development of anti-cancer medications. This study employed a relatively non-invasive approach to establish an orthotopic hepatocellular carcinoma model in immune-competent rats. This was done by ultrasound-guided implantation of cancer cells and the model was used to evaluate the therapeutic efficacy of short-term and low-dose epirubicin chemotherapy.MethodsRat Novikoff hepatoma cells were injected percutaneously into the liver lobes of Sprague-Dawley rats under the guidance of high resolution ultrasound. The implantation rate and the correlation between dissected and ultrasound-measured tumor sizes were evaluated. A similar induction procedure was performed by means of laparotomy in a different group of rats. Pairs of tumor measurement were compared by ultrasound and computerized tomography scan. Rats with a successful establishment of the tumor were divided into the treatment (7-day low-dose epirubicin) group and the control group. The tumor sizes were non-invasively monitored by the same ultrasound machine. Blood and tumor tissues from tumor-bearing rats were examined by biochemical and histological analysis respectively.ResultsUltrasound-guided implantation of Novikoff hepatoma cells led to the formation of orthotopic hepatocellular carcinoma in 60.4% (55/91) of the Sprague-Dawley rats. Moreover, tumor sizes measured by ultrasound significantly correlated with those measured by calipers after sacrificing the animals (P < 0.00001). The rate of tumor induction by ultrasound-guided implantation was comparable to that of laparotomy (55/91, 60.4% vs. 39/52, 75%) and no significant difference in sizes of tumor was noted between the two groups. There was a significant correlation in tumor size measurement by ultrasound and computerized tomography scan. In tumor-bearing rats, short-term and low-dose epirubicin chemotherapy caused a significant reduction in tumor growth, and was found to be associated with enhanced apoptosis and attenuated proliferation as well as a decrease in the microvessel density in tumors.ConclusionsUltrasound-guided implantation of Novikoff hepatoma cells is an effective means of establishing orthotopic hepatocellular carcinoma in Sprague-Dawley rats. Short-term and low-dose epirubicin chemotherapy had perturbed tumor progression by inducing apoptosis and neovascularization blockade.

Celecoxib suppresses hepatoma stemness and progression by up-regulating PTEN

“…However, the therapeutic efficacy of celecoxib for HCC has not been tested in immune-competent animals with orthotopic hepatoma. Thus, this study investigated the therapeutic potential and mechanism of celecoxib in rat Novikoff hepatoma induced by US-guided implantation [21]. …”

Ultrasound-Guided Intratumoral Delivery of Doxorubicin from in Situ Forming Implants in a Hepatocellular Carcinoma Model

“…On average implants released between 4.4 and 6.8 μg/day of doxorubicin in vitro, which was greater than the 1 μg/ml needed to reduce cell viability by 95%. Furthermore, the ability to inject an implant into an orthotopic tumor under image guidance is not only faster, but also reduces complications that arise from placement through laparotomy such as bleeding and infection [42].…”

“…After anesthetization, using 1% isofluorane at a flowing oxygen rate of 1 l/m (EZ150 Isoflurane Vaporizer, EZ Anesthesias™), the rats were shaved and the incision site was cleaned using isopropanol and betadine. Then an incision was made along the ventral midline in order to expose liver, and 100 μl N1-S1 cells were injected into the liver parenchyma using a 26-gauge syringe at a concentration of 5 × 10 6 cells/ml in IMEM [42].…”

“…Immune deficient mice can be used to make a subcutaneous xenograft, but these models lack the physiological complexity of the liver. The Novikoff hepatoma (N1-S1) cells can be used to create an orthotopic model in Sprague-Dawley rats, which not only more accurately recapitulate the tumor-associated physiology, but the model uses immune competent animals [42]. Physiological features are important to consider with minimally invasive procedures, because the collateral blood supply may reduce treatment efficacy of the system [42].…”

High-Resolution Ultrasound Allows Percutaneous Initiation and Surveillance of Prostate Cancer in an Orthotopic Murine Model

“…Another model used such a procedure for orthotopic hepatocellular carcinoma. The ultrasound method led to the formation of orthotopic liver tumors in 60.4%, indicating a slightly lower take rate than after laparotomy (75%), but there were no significant differences in tumor sizes between the two groups [21]. Another model for liver tumors showed a tumor take rate of almost 100% [22].…”