Local administration of liposomal adriamycin inhibited proliferation of metastatic cells in axillary lymph nodes in rabbit breast cancer model

ObjectiveTo assess the inhibitory effects of liposomal adriamycin (LADR) locally injected into mammary glands of VX2 tumor-bearing rabbits on proliferation of lymph nodal metastatic cells.MethodsTwenty-one VX2 tumor-bearing rabbits were randomly and equally divided into 3 groups. Rabbits were randomized to receive sham treatment (Group I), subcutaneous LADR around tumor (Group II) and intravenous free adriamycin (Group III), respectively. Breast tumor and axillary lymph nodes were harvested after 3 repeated treatment. Nodal sizes of both pre- and post-treatment were measured. Proliferating cell nuclear antigen (PCNA) mRNA in both tumor and lymph nodes were determined by RT-PCR.ResultsThe mean size of axillary lymph nodes in Group I, II and III increased by 3.70%, 1.55% and 2.89%, respectively, with significant difference between Group III and I (P=0.004) and between Group II and III (P=0.002). Relative expression values of PCNA mRNA in breast tumors of Group I, II and III were 0.486, 0.513 and 0.396, respectively. For Group III, PCNA mRNA was significantly less expressed than that in Group I (P=0.023) and II (P=0.005). Relative expression values of PCNA mRNA in axillary lymph nodes of Group I, II and III were 0.541, 0.329 and 0.450, respectively. Compared with Group I, Group III showed a markedly decreased expression of PCNA (P=0.021). The least level of PCNA mRNA was found in Group II, with a significant difference from that in Group III (P=0.004).ConclusionLocal injection of LADR was an effective therapeutic regimen for lymphatic metastases from breast cancer, regardless of its little effect on primary tumor.