Unique Gene Expression Profiles within South Africa Are Associated with Varied Chemotherapeutic Responses in Conventional Osteosarcoma

TL;DR

This study identifies gene expression patterns in South African osteosarcoma patients that correlate with how well they respond to chemotherapy.

Contribution

The study reveals unique gene expression profiles in South African osteosarcoma patients linked to chemotherapeutic responses, offering potential targets for treatment.

Findings

Downregulation of ABCC3, ABCB1-p-glycoprotein, ERCC1, RFC1, and p53 genes was observed in osteosarcoma tumors.

Upregulated ERCC1 gene expression predicted poor chemotherapeutic response.

Age, histological subtypes, and gene expression levels of ABCC3, ERCC1, and RFC1 were significant predictors of chemotherapeutic response.

Abstract

This study aimed to determine the gene expression profiles associated with chemotherapeutic responses in conventional osteosarcomas (COS) within South Africa. We observed a significant downregulation in the ATP binding cassette subfamily C members (ABCC3 and ABCB1-p-glycoprotein), excision repair cross-complimenting group 1 (ERCC 1), replication factor C subunit 1 (RFC1), and tumour protein 53 (p53) genes in the COS tumours compared to the healthy donors. Furthermore, an upregulated ERCC1 gene expression level predicted a poor chemotherapeutic response. Additionally, the predictors of COS chemotherapeutic response comprised age, chondroblastic and osteoblastic histological subtypes, and ABCC3, ERCC1, and RFC1 gene expression.

Background: We determined the predictive gene expression profiles associated with chemo-response in conventional osteosarcomas (COS) within South Africa. Materials and methods: In 28 patients, we performed an RNA extraction, cDNA synthesis, and quantitative analysis using the RT-PCR 2−∆∆CT method to determine the fold change in gene expression alongside GAPDH (housekeeping gene). Results: We observed a significant downregulation in the mRNA expression profiles of ABCB1-p-glycoprotein (p = 0.0007), ABCC3 (p = 0.002), ERCC1 (p = 0.007), p-53 (p = 0.007), and RFC1 (p = 0.003) in the COS patients compared to the healthy donors. Furthermore, ABCB1-p-glycoprotein (p = 0.008) and ABCC3 (p = 0.020) exhibited a significant downregulation in the COS tumour tissues when compared to the healthy donors. In our univariate logistic regression, the predictors of chemotherapeutic response comprised ERCC1 [restricted cubic spline (RCS) knot: OR −0.27; CI −0.504 to −0.032; p = 0.036]; osteoblastic subtype [OR −0.36; CI −0.652 to −0.092; p = 0.026); fibroblastic subtype [OR 0.91; CI 0.569 to 1.248; p < 0.001]; and mixed subtype [OR 0.53; CI 0.232 to 0.032; p = 0.032]. In our multivariable logistic regression, the significant predictors of chemotherapeutic response comprised age [RCS knot: OR −2.5; CI −3.616 to −1.378; p = 0.022]; ABCC3 [RCS knot: OR 0.67; CI 0.407 to 0.936, p = 0.016]; ERCC1 [RCS knot: OR 0.57; CI 0.235 to 0.901; p = 0.044]; RFC1 [RCS knot: OR −1.04; CI −1.592 to −0.487; p = 0.035]; chondroblastic subtype [OR −0.83; CI −1.106 to −0.520; p = 0.012]; and osteoblastic subtype [OR −1.28; CI −1.664 to −0.901; p = 0.007]. Conclusions: In this South African cohort, we observed the unique gene expression profiles of osteosarcoma tumourigenesis and chemotherapeutic responses. These may serve as prognostication and therapeutic targets. Larger-scale research is needed on the African continent.

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