Abstract 97: The effect of hyaluronan degradation on the uptake and cytotoxic activity of liposome-encapsulated doxorubicin in 3D tumor spheroid models
Authors: Gao Feng , Zimmerman Susan , Chen Kelly , Maneval Daniel C. , Zhao Chunmei 
Published: August 2019

Abstract
The accumulation of hyaluronan (HA) in the solid tumor microenvironment (TME) can be associated with poor prognosis in several human cancers. Accumulation of HA in the TME can increase interstitial pressure that compresses local blood vessels and impairs the access of anti-cancer therapy. In preclinical models, enzymatic degradation of HA by pegvorhyaluronidase alfa (PEGPH20; PVHA), a PEGylated form of recombinant human hyaluronidase PH20 (rHuPH20), is associated with decreased tumor interstitial pressure, improved tumor vascular perfusion, and increased access and anti-tumor efficacy of cytotoxic and immunotherapies.
The functional effect of HA degradation on the TME has been mostly characterized in animal tumor models. Here, we describe the utilization of 3D tumor spheroid models to evaluate the effects of HA degradation on the cytotoxic effect of anti-cancer therapies. A number of commonly used human colorectal cancer (CRC) cell lines were assessed for HA accumulation and tumor spheroid morphology: HCT 116, HT-29 parental, and HT-29/HAS3 (HT-29 cells engineered to over-express hyaluronan synthase 3). CRC 3D tumor spheroid models were developed to evaluate the uptake and cytotoxic activity of liposome-encapsulated doxorubicin (DOX) using the IncuCyte® S3 Live-Cell Analysis System. The effect of HA degradation on DOX uptake and cytotoxic activity was initially tested with rHuPH20 treatment in all three models, and further evaluated with PVHA treatment in HT-29 parental and HT-29/HAS3 models.
A dose-dependent uptake and cytotoxic activity of DOX was observed in HCT 116 tumor spheroids. HA degradation after rHuPH20 treatment enhanced DOX uptake by an average of 6.1% (up to 7.7%) and cytotoxicity by an average of 37.9% (up to 58.2%) over the 5-day duration of the experiment compared with DOX alone. Dose-dependent uptake and cytotoxic activity of DOX in HT-29/HAS3 tumor spheroids were enhanced with rHuPH20 treatment to a greater extent than in HT-29 parental tumor spheroids. Specifically, rHuPH20 treatment led to an average increase in DOX uptake of 9.2% (up to 14.6%) with HT-29/HAS3 spheroids and 2.6% (up to 5.1%) with HT-29 parental spheroids. The addition of rHuPH20 resulted in an average increase in DOX cytotoxicity of 101% (up to 227.6%) with HT-29/HAS3 spheroids and 24.9% (up to 63.9%) with HT-29 parental spheroids. Enhanced uptake and cytotoxic activity of DOX was also observed with PVHA treatment in HT-29 and HT-29/HAS3 models.
These data corroborate our previous findings with in vivo tumor models, in which the combination of PVHA-mediated HA degradation and other anti-cancer therapies display enhanced anti-tumor activity compared with either agent alone. Further, 3D tumor spheroid models may be used to evaluate the effect of extracellular matrix remodeling such as HA degradation and serve as a bridge between 2D cell-based assays and in vivo tumor models.
Citation Format: Feng Gao, Susan Zimmerman, Kelly Chen, Daniel C. Maneval, Chunmei Zhao. The effect of hyaluronan degradation on the uptake and cytotoxic activity of liposome-encapsulated doxorubicin in 3D tumor spheroid models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 97.