Engineered Living Materials as Programmable Therapeutic Implants for Pancreatic Cancer

Abstract public domain (NIH RePORTER)

PROJECT SUMMARY Pancreatic ductal adenocarcinoma (PDAC) is a devastating cancer with a 5-year survival rate below 5%. A cen- tral challenge in PDAC treatment is poor drug delivery due to its avascular and dense extracellular matrix. This proposal aims to develop an innovative drug delivery platform by encapsulating drug-producing bacteria within an implantable hydrogel, creating an engineered living material (ELM) for localized, dynamic, and tunable ther- apeutic delivery to PDAC tumors. This proposal builds upon the project I am currently completing with support from an NCI K00 fellowship (K00 CA253756), where I discovered a novel mechanical feedback mechanism to control bacterial growth within a hydrogel matrix. I have further developed inducible genetic circuits and identified potent bacterially-produced anticancer toxins against PDAC cells. During the K99 phase, I will engineer a novel hydrogel to encapsulate therapeutic bacteria (Aim 1) and prevent post-surgical recurrence with inducible drug delivery (Aim 2). In Aim 1, I will fabricate stiff and tough polyvinyl alcohol (PVA) cryogels to mechanically confine bacterial growth and prevent escape while maintaining bacterial viability and optimizing drug release profiles. Probiotic E. coli will be encapsulated within the PVA to create a composite ELM. In Aim 2, I will develop an implantable ELM to prevent post-surgical recurrence by delivering anticancer therapeutics in a triggerable and sustained manner. By engineering a bacterial genetic circuit that allows small-molecule-triggered expression of anticancer toxin payloads, I will enable high-dosage and inducible delivery of therapeutics. This ELM will be implanted at the surgical cavity of partially resected PDAC xenograft mouse models to address the clinical challenge of recurrence. During the R00 phase, I will focus on overcoming PDAC's immunosuppressive microenvironment by deliv- ering sequential immunotherapies (Aim 3). I will develop an in situ cancer vaccine strategy using peritumorally- implanted ELM. Specifically, I will engineer a sequential gene circuit to initially secrete cytotoxic molecule, re- leasing tumor-associated antigens, and degrade dense stroma. Subsequently, the ELM will release GM-CSF to recruit and stimulate antigen-presenting cells. Therapeutic efficacy and immune responses will be characterized in syngeneic and genetically engineered pancreatic cancer mouse models. This approach will leverage the in- trinsic and engineered immunomodulation from ELM to temporally control antitumoral immunity. Collectively, the successful completion of this proposal will integrate material science and synthetic biology to create a novel therapeutic approach for PDAC, aiming to improve patient outcomes by preventing recurrence and enhancing antitumoral immunity.

Public health relevance public domain (NIH RePORTER)

PROJECT NARRATIVE A long-standing challenge of pancreatic cancer is poor drug delivery and immunosuppressive environment, con- tributing to reduced drug efficacy and a low survival rate. Implantable drug depots enable direct therapeutic targeting of tumors but often lack the precise dosage and kinetics control necessary for effective treatment. This proposal integrates genetically engineered bacteria within implantable materials, creating novel engineered living materials that locally and dynamically deliver anticancer therapeutics to orchestrate cytotoxic effects and anti- tumoral immunity against pancreatic cancer.