Functional and mutational analysis after radiation and cetuximab treatment on prostate carcinoma cell line DU145

Raik Schneider,Burkhard Jandrig,Hans-Joachim Ochel,Peter Hass,Günther Gademann,Karsten Neumann,Thomas Brunner,Frank Christoph,Martin Schostak,Mathias Walke

doi:10.1186/s13014-021-01859-6

Abstract

BackgroundEpidermal Growth Factor Receptor is often overexpressed in advanced prostate carcinoma. In-vitro-studies in prostate carcinoma cell line DU145 have demonstrated increased sensibility to radiation after cetuximab treatment, but clinical data are not sufficient to date.MethodsWe analyzed effects of radiation and cetuximab in DU145 and A431 using proliferation, colony-forming-unit- and annexin-V-apoptosis-assays. Changes in protein expression of pEGFR and pERK1/2 after radiation and cetuximab treatment were analyzed. Using NGS we also investigated the impact of cetuximab long-term treatment.ResultsCell counts in DU145 were reduced by 44% after 4 Gy (p = 0.006) and 55% after 4 Gy and cetuximab (p < 0.001). The surviving fraction (SF) was 0.69 after 2 Gy, 0.41 after 4 Gy and 0.15 after 6 Gy (each p < 0.001). Cetuximab treatment did not alter significantly growth reduction in 4 Gy radiated DU145 cells, p > 0.05 or SF, p > 0.05, but minor effects on apoptotic cell fraction in DU145 were detected. Using western blot, there were no detectable pEGFR and pERK1/2 protein signals after cetuximab treatment. No RAS mutation or HER2 amplification was detected, however a TP53 gen-mutation c.820G > T was found.ConclusionsRadiation inhibits cell-proliferation and colony-growth and induces apoptosis in DU145. Despite blocking MAP-Kinase-pathway using cetuximab, no significant radiation-sensitizing-effect was detected. Cetuximab treatment did not induce resistance-mutations. Further research must clarify which combination of anti-EGFR treatment strategies can increase radiation-sensitizing-effects.

Highlights

Epidermal Growth Factor Receptor is often overexpressed in advanced prostate carcinoma
The daily growth rate from a starting cell count of 20,000 sown, untreated cells in cell line DU145 and 10,000 cells in A431 was significant in the observed period of nine days
Counts in DU145 between control and radiation at 4 Gy as well as control and radiation + cetuximab treated cells; there was no difference between control and cells treated with cetuximab only

Summary

Introduction

Epidermal Growth Factor Receptor is often overexpressed in advanced prostate carcinoma. In-vitrostudies in prostate carcinoma cell line DU145 have demonstrated increased sensibility to radiation after cetuximab treatment, but clinical data are not sufficient to date. Prostate carcinoma represents the most common cancer disease in men and affects 26% of all male cancer patients [1]. The Epidermal Growth Factor Receptor is a 170 kD transmembraneous glycoprotein, its gene is located on chromosome 7p11.2 and it triggers in epithelial tissues, mitosis, apoptosis, migration and cell differentiation [5, 6]. EGFR is overexpressed in nearly 50% of all cases of the prostate carcinomas [7]. EGFR protein expression levels increase with tumor stage and were highly correlated with hormone refractory status [8, 9].

Methods

Results

Conclusion