Research Summary
Patients diagnosed with advanced cholangiocarcinoma (CCA) have poor overall outcomes and face
limited treatment options. Small interfering RNA (siRNA) therapeutics offer an attractive strategy for silencing
oncogenic drivers of CCA that lack FDA-approved molecularly-targeted therapeutics, particularly KRAS, which
is mutated in ~22% of intrahepatic and ~42% of extrahepatic CCAs. Combination siRNA therapeutics may be
devised to preempt compensatory resistance pathways that frequently arise in the course of targeted therapy.
Furthermore, siRNA may be targeted to sites of malignancy, avoiding adverse effects due to molecularly on-
target activity in healthy organs, as is seen with many small molecule drugs. However, delivery challenges
including nuclease degradation, rapid clearance, and lack of a mechanism for cellular uptake or endosome
escape have traditionally limited clinical use of siRNA. Our group has recently developed technology to
chemically modify siRNAs with twin fatty acids (siRNA-L2) that form non-covalent nanocomplexes with
endogenous albumin (alb-NCs). Since albumin is ordinarily long-circulating in the vasculature but is actively
taken up by tumors, we have found that alb-NCs extend siRNA circulation time, promote homogeneous tumor
penetration, and increase tumor-selective siRNA uptake. Such a technology is well-suited for fibrotic tumors like
CCA, for which an active uptake mechanism is necessary for delivery of large biologic therapeutics. However,
the siRNA-L2 design has not yet been integrated with “on-board” functionality to escape from endosomes, which
represent a critical barrier to siRNA activity. In this project, I propose to optimize and tailor the siRNA-L2 alb-NC
platform to enable efficient tumor-selective knockdown of oncogenic drivers in CCA.
The studies proposed here will test the hypothesis that alb-NC-mediated delivery of a combination of
siRNAs targeting both KRAS and complementary resistance pathways will provide therapeutic benefit in KRAS-
driven cholangiocarcinoma. First, I will chemically optimize alb-NCs for efficient endosomal escape and
intracellular siRNA delivery. Second, I will credential gene targeting of KRAS in combination with rationally-
selected complementary gene targets involved in mTOR signaling or apoptotic pathways implicated in KRAS
treatment resistance. I will then perform pre-clinical therapeutic studies using alb-NCs to deliver KRAS-based
siRNA combinations to orthotopic mouse models of KRAS-mutant intrahepatic CCA. This project will thus
address a pressing need for new targeted therapeutic approaches in CCA by developing efficacious siRNA
delivery technologies to target key gene combinations in KRAS-driven disease.