Unfolding the Potency of Adenosine in Targeting Triple Negative Breast Cancer via Paclitaxel-Incorporated pH-Responsive Stealth Liposomes

Triple-negative breast cancer (TNBC) belongs to the category of the most destructive forms of breast cancer. Being a highly potent chemotherapeutic agent, paclitaxel (PTX) is extensively utilized in the management of various cancers. Commercially available PTX formulations contain non-targeted drug carriers that result in low antitumor activity because of non-specific tissue distribution. Thus, to resolve this issue, we designed PTX-loaded pH-sensitive liposomes (pH Lipos) in the present investigation and used adenosine (ADN) as a targeting ligand. Further, D-alpha-tocopheryl polyethylene glycol succinate (TPGS) was incorporated into the liposomes to impart a stealth effect to the system. For the development of these pH Lipos, different conjugates were synthesized (ADN-CHEMS and TPGS-ADN) and further utilized for the preparation of ADN-PEG-pH Lipo and ADN-pH Lipo by a thin-film hydration method. DOPE:HSPC:CHEMS:cholesterol at a molar ratio of 3:3:2:2 was selected for the preparation of pH-Lipo possessing 7.5% w/w drug loading. They showed a particle size below 140 nm, a PDI below 0.205, and a % EE greater than 60%. All of the pH Lipos displayed a biphasic pattern of PTX release at pH 7.4 and 5.5. However, the percent drug release at pH 5.5 was substantially greater because of the pH-sensitive nature of the liposomes. The MDA MB 231 and 4T1 cell lines depicted improvement in the qualitative as well as quantitative cellular uptake of PTX ADN-PEG-pH Lipo with a substantial decrease in the IC50 value. Moreover, a higher apoptotic index was observed with pH Lipo compared to free PTX. PTX ADN-PEG-pH Lipo revealed a 3.98-and 3.41-fold rise in the AUC and t1/2 values of PTX compared to Intaxel, respectively. Overall, characteristic decreases in tumor volume and serum toxicity marker levels were observed, which confirmed the development of an efficient and safe formulation.

Automated summary

In this study, a novel pH-sensitive liposome loaded with paclitaxel (PTX) and targeted with adenosine (ADN) was designed. The liposomes exhibited desirable particle size, drug encapsulation efficiency, and pH-responsive release. In cellular experiments, ADN-PEG-pH liposomes showed improved cellular uptake and apoptosis induction compared to free PTX. Moreover, ADN-PEG-pH liposomes demonstrated higher drug exposure and longer half-life than Intaxel. Overall, the development of this new drug delivery system is of great significance for TNBC treatment.