Efficiency of Different Treatment Regimens Combining Anti-tumor and Anti-inflammatory Liposomes for Metastatic Breast Cancer.

Nanomedicines such as liposomes have been widely exploited in the treatment of tumors, and are also involved in combination therapies to enhance anti-tumor efficacy and reduce side effects. However, few studies have systematically discussed the significance and optimized regimens for nanomedicine-based combination therapy. In this study, we used anti-inflammatory and anti-tumor liposomes for co-administration, and compared three regimens: intermittent, metronomic, or sequential administration (IA, MA, and SA). The anti-inflammatory liposome HA/TN-CCLP was constructed in our previous research, which co-loaded curcumin (CUR) and celecoxib (CXB), modified with TAT-NBD peptide (TN) and finally coated with hyaluronic acid (HA), thereby inhibiting NF-κB and STAT3 pathways in the treatment of metastatic breast cancer. Furthermore, doxorubicin liposomes with and without TN modification (namely TN-DOXLP and DOXLP) were constructed and administrated with HA/TN-CCLP. The anti-tumor and anti-metastasis efficacy of different regimens was investigated. Results showed that in vitro cytotoxicity of DOXLP and TN-DOXLP was significantly enhanced when combined with HA/TN-CCLP. In vivo experiments also revealed the superiority of three combination therapies in inhibiting tumor growth, prolonging the survival of tumor-bearing mice, inducing apoptosis, and reducing lung metastases. In particular, the combination therapy could reduce MDSCs (Gr-1/CD11b) and CSCs (CD44/CD24) infiltration, which are two important factors in tumor metastasis and recurrence. Among three regimens, sequential administration (SA) showed the best therapeutic outcome and was especially effective for the inhibition of CSCs. In general, the results demonstrated that combination therapy, particularly the sequential administration of anti-inflammatory and anti-tumor liposome, was superior to monotherapy in inhibiting the development and metastasis of inflammation-related tumors.