Nanoparticle formulations of cisplatin for cancer therapy

Repurposing platinum-based chemotherapies for multi-modal treatment of glioblastoma

Glioblastoma (GBM) is a fatal brain cancer for which new treatment options are sorely needed. Platinum-based drugs have been investigated extensively for GBM treatment but few have shown significant efficacy without major central nervous system (CNS) and systemic toxicities. The relative success of platinum drugs for treatment of non-CNS cancers indicates great therapeutic potential when effectively delivered to the tumor region(s). New insights into the broad anticancer effects of platinum drugs, particularly immunomodulatory effects, and innovative delivery strategies that can maximize these multi-modal effects and minimize toxicities may promote the re-purposing of this chemotherapeutic drug class for GBM treatment.

Interstitial Release of Cisplatin from Triggerable Liposomes Enhances Efficacy against Triple Negative Breast Cancer Solid Tumor Analogues

Liposomal cisplatin, a promising triple negative breast cancer treatment modality, has been shown to decrease toxicities associated with cisplatin's free agent form. However, the heterogeneous intratumoral distributions of the liposomes themselves, combined with limited release of cisplatin from them contribute to limited penetration of cisplatin within tumors reducing efficacy. This study uses pH-responsive liposomes designed to release cisplatin within the acidic tumor interstitium (7.0 > pH ≥ 6.0) with a dual aim (1) to improve the penetration of the free drug within tumors on the assumption of greater diffusivities based on the free drug's much smaller size than its carrier's size and (2) to increase the availability of the free agent near cancer cells deep into the tumor. On cell monolayers treated with pH-releasing liposomal cisplatin, acidification of the extracellular solution resulted in decreased LD50 values, which were significantly lower than the LD50 values for non-pH-releasing liposomal cisplatin. In multicellular spheroids with acidic interstitia, pH-releasing liposomal cisplatin significantly decreased spheroid volumes relative to non-pH-releasing liposomal cisplatin. Improved efficacy was correlated with increased spheroid penetration of a fluorescent cisplatin surrogate. These findings demonstrate that interstitial release of cisplatin by pH-responsive liposomes may improve the intratumoral distributions of the free drug enhancing efficacy.