Overcoming chemoresistance in osteosarcoma: the role of autophagy in cell death or survival following chemotherapy

Rosa, Gabriel Santos Neves, Burczynska, Beata ORCID: https://orcid.org/0000-0003-4101-8525, Stordal, Britta K. ORCID: https://orcid.org/0000-0002-7892-951X and Roberts, Helen C. ORCID: https://orcid.org/0000-0003-1974-0319 (2018) Overcoming chemoresistance in osteosarcoma: the role of autophagy in cell death or survival following chemotherapy. In: 2018 NCRI Cancer Conference, 04-06 Nov 2018, Glasgow, Scotland. . [Conference or Workshop Item]

Abstract

Background: For the past 30 years, long-term survival rates in metastatic and recurrent osteosarcoma (OS) patients has remained unchanged. Drug resistance is thought to be the main cause and overcoming this phenomenon is a key step towards greater efficacy with OS therapy. Increasing evidence shows that autophagy, a ‘self-degradation’ pathway, can act as a protective mechanism to help cancer cells thrive under chemotherapeutic stress. The current study investigated the function of autophagy in two OS cell lines of varying metastatic capacity in response to two standard chemotherapy treatments, doxorubicin and cisplatin.

Method: HOS-143B (highly metastatic) and MG-63 (less metastatic) cell lines were treated with doxorubicin (Dox) and cisplatin (Cis) for 48h (1). An acid phosphatase-based proliferation assay was used to calculate IC50s of each drug. Autophagy activation was determined based on the protein expression of p62 and autophagic flux (LC3-I/LC3-II protein conversion), analysed with Western blotting. Gene expression of MAPLC3B and p62/SQSTM1 was measured using RT-PCR. LC3-II punctate formation was detected using immunofluorescence.

Results: Both drugs significantly induced autophagic flux in MG63 and HOS-143B cells as shown by increased LC3-I to LC3-II conversion, with Dox increasing LC3-II expression to a higher extent compared with Cis. Immunofluorescence of LC3-II punctate confirmed this pattern. Dox treatment was also associated with reduced p62/SQSTM1 protein, indicating greater autophagic clearance. MAPLC3B and p62/SQSTM1 gene expression was elevated in both Dox treated cell lines.

Conclusion: In both highly metastatic HOS-143B cells and less metastatic MG63 cell line, dox treatment induces autophagy to a greater extent when compared with cis. These results will be coupled with apoptosis assays to compare the level of autophagy induction and cell death. It is envisaged that enhancing our knowledge on the role of autophagy in chemoresistance will help us to identify novel targets for osteosarcoma treatment.

Actions (login required)

View Item

Statistics

DownloadsShow export options

Export as CSVXMLJSON

Activity Overview

6 month trend

0Downloads

6 month trend

64Hits

Additional statistics are available via IRStats2.