PET Evaluation For The Therapeutic Effect Of Huaier Extract On Breast Cancer Xenografts In Nude Mice

ObjectiveThis study aimed to monitor and evaluate the therapeutic effect of Huaier extract (trametes robiniophila murr) on Luminal B and Triple negative breast cancer xenografts by small animal positron emission tomography (micro-PET) imaging, and to provide evidence for the application of Huaier extract on the treatment of different breast cancer subtypes.MethodsBALB/c female nude mice bearing subcutaneous human BT474m (Luminal B) or MDA-MB-231 (Triple negative) breast cancer xenografts were randomized into control and treatment groups (n= 6 in each group). Mice were treated daily with saline or Huaier extract (2.5g/kg) by gavage for 3 weeks. Tumor size and body weight were measured twice a week.18F-FDG micro-PET was performed before treatment (Week 0) and on Week 1,2,3. Following the last micro-PET acquisition, mice were sacrificed and tumor tissues were collected for immunohistochemical studies to assess the expression of Ki-67, Caspase-3 and vascular endothelial growth factor (VEGF).ResultsFor BT474 xenografts, tumor growth index (TGI) and the 18F-FDG uptake of Huaier group decreased significantly compared to the control after 3 weeks of treatment (P<0.05). However, for MDA-MB-231 xenografts, no significant differences of TGI and 18F-FDG uptake were found between Huaier group and the control after treatment (P> 0.05). Immunohistochemical findings showed Huaier group had lower expression of Ki-67 and VEGF as well as higher expression of Caspase-3 compared with the control in BT474 xenografts (P< 0.05), while Huaier group had no significantly different expression of Ki-67, VEGF and Caspase-3 compared to the control in MDA-MB-231 xenografts (P> 0.05).ConclusionOur results suggested that Huaier extract was effective in Luminal B breast cancer xenografts, but showed no significant effect in Triple negative breast cancer xenografts. Moreover,18F-FDG PET was an important method to noninvasively monitor and evaluate the therapeutic effect of Huaier extract on Luminal B breast cancer subtype.