# Chondrosarcoma: Multi-Targeting Therapeutic Effects of Doxorubicin, BEZ235, and the Small Molecule Aspartyl-Asparaginyl-β-hydroxylase Inhibitor SMI1182

## TL;DR

This study explores how combining doxorubicin, BEZ235, and SMI1182 can improve treatment for chondrosarcoma by targeting multiple pathways involved in tumor growth.

## Contribution

The novel contribution is the identification of a triple-drug combination that synergistically targets ASPH, Notch, and PI3K/mTOR pathways in chondrosarcoma.

## Key findings

- SMI1182 and BEZ235, with or without doxorubicin, significantly reduced tumor cell motility.
- Combined treatments caused additive cytotoxic effects by reducing ASPH, Notch, and insulin receptor substrate type I expression.
- Triple-drug therapy could potentially improve survival by targeting multiple mediators of aggressive tumor behavior.

## Abstract

This study compares molecular features in intermediate and high-grade conventional chondrosarcomas and their responses to individual, combination, and novel chemotherapeutic agents. The findings may account for differences in aggressive tumor behavior in relation to histopathological grade and suggest that chondrosarcoma tumor grade should be factored in for predicting the efficacy of emerging chemotherapeutic approaches.

Background/Objectives: Chondrosarcoma (CS), the most common malignant bone tumor in adults, exhibits a poor prognosis due to high rates of post-surgical recurrence and metastasis, and resistance to chemotherapy. CS’s abundant expression of aspartyl-asparaginyl-β-hydroxylase (ASPH), which drives invasive tumor growth via Notch and PI3K/mTOR activation, opens opportunities for treatment in combination with standard Doxorubicin (DOX) chemotherapy. We hypothesized that the small molecule inhibitor SMI1182, which targets the catalytic domain of ASPH, and BEZ235, which targets PI3K/mTOR, could enhance the chemotherapeutic effects of DOX. Human CS1 (Grade 3) and CDS11 (Grade 2) conventional CS cell lines were treated with broad dose ranges of DOX, BEZ235, or SMI1182 as mono- or combination therapy to assess their anti-tumor effects on cell viability, toxicity, and motility. Methods: Mechanistic studies included the analysis of ASPH expression, Notch signaling, and insulin/IGF/IRS pathway activation through mTOR. DOX, BEZ235, or SMI1182 treatments caused dose-dependent cell loss and cytotoxicity. Results: SMI1182 and BEZ235, with or without DOX, significantly reduced directional motility. Combined treatments had additive cytotoxic effects linked to the reduced expression of ASPH, Notch transcription factors, and insulin receptor substrate type I, which positively regulates both ASPH and Notch. Conclusions: Triple-drug treatment with DOX, SMI1182, and BEZ235 could potentially improve disease-free survival with CS by the simultaneous targeting of multiple upstream mediators of aggressive malignant tumor cell behavior.