Sustained Supratherapeutic Paclitaxel Delivery Enhances Irreversible Sarcoma Cell Death

Area of Science:

• Oncology
• Biomaterials Science
• Drug Delivery

Background:

• Sarcoma resection has a high risk of locoregional recurrence, leading to increased morbidity and mortality.
• Systemic paclitaxel (PTX) delivery is limited by dose constraints and inability to achieve sustained, supratherapeutic concentrations at the tumor site.
• The biological mechanisms behind the enhanced efficacy of localized PTX delivery via polymer films remain largely unknown.

Purpose of the Study:

• To investigate the in vitro and in vivo biological effects of supratherapeutic paclitaxel (PTX) concentrations delivered by polymer films for sarcoma treatment.
• To elucidate the cellular and molecular mechanisms underlying the efficacy of localized PTX delivery in preventing sarcoma recurrence.

Main Methods:

• In vitro dose- and time-dependent PTX efficacy studies on human chondrosarcoma (CS-1) cells.
• In vivo evaluation of PTX-eluting films in murine models of recurrent sarcoma, including patient-derived liposarcoma (LP6) and leiomyosarcoma (LMS20).
• Analysis of cell cycle arrest, apoptosis induction, p21 expression, DNA integrity, and gene expression using microarray analysis.

Main Results:

• In vitro, prolonged PTX exposure significantly reduced IC50 values for CS-1 cells.
• In vivo, PTX films delivered supratherapeutic doses (>130 μmol/L) to the tumor bed, causing irreversible cell cycle arrest and apoptosis in multiple sarcoma types.
• Supratherapeutic PTX upregulated p21 in arrested cells, induced apoptosis and cell death within 4 hours, and led to poor DNA integrity, consistent with microarray findings.

Conclusions:

• Localized, sustained delivery of supratherapeutic paclitaxel via polymer films effectively reduces sarcoma lethality in vivo.
• This approach offers a novel paradigm for preventing sarcoma recurrence by overcoming the limitations of systemic drug delivery.
• The study elucidates the biological basis for enhanced PTX efficacy, involving cell cycle arrest, apoptosis, and DNA damage induction.