Multi‑drug‑resistance efflux in cisplatin‑naive and cisplatin‑exposed A2780 ovarian cancer cells responds differently to cell culture dimensionality

Abstract

A primary reason for chemotherapy failure is chemoresistance, which is driven by various mechanisms. Multi-drug resistance (MDR) is one such mechanism that is responsible for drug extrusion from the intracellular space. MDR can be intrinsic and thus, may pre-exist the first application of chemotherapy. However, MDR may also be acquired during tumor exposure to chemotherapeutic agents. To understand whether cell clustering can influence intrinsic and acquired MDR, the present study assessed cultured monolayers (representing individual cells) and spheroids (representing clusters) formed by cisplatin-naïve (intrinsic MDR) and cisplatin-exposed (acquired MDR) lines of ovarian cancer A2780 cells by determining the cytometry of reaction rate constant (CRRC). MDR efflux was characterized using accurate and robust cell number vs. MDR efflux rate constant (k MDR ) histograms. Both cisplatin-naïve and cisplatin-exposed monolayer cells presented unimodal histograms; the histogram of cisplatin-exposed cells was shifted towards a higher k MDR value suggesting greater MDR activity. Spheroids of cisplatin-naïve cells presented a bimodal histogram indicating the presence of two subpopulations with different MDR activity. In contrast, spheroids of cisplatin-exposed cells presented a unimodal histogram qualitatively similar to that of the monolayers of cisplatin-exposed cells but with a moderate shift towards greater MDR activity. A flow-cytometry assessment of multidrug resistance-associated protein 1 transporter levels in monolayers and dissociated spheroids revealed distributions similar to those of k MDR , thus, suggesting a plausible molecular mechanism for the observed differences in MDR activity. The observed greater effect of cell clustering on intrinsic rather than in acquired MDR can help guide the development of new therapeutic strategies targeting clusters of circulating tumor cells.

Aryl Hydrocarbon Receptor Promotes Cell Growth, Stemness Like Characteristics, and Metastasis in Human Ovarian Cancer via Activation of PI3K/Akt, β-Catenin, and Epithelial to Mesenchymal Transition Pathways

“…Surprisingly, A2780cis cells were resistant to the anti-apoptotic effect of AhR activation as evidenced by no induction of the levels of BCL-2 proteins, cell cycle phases, and DNA strand break. Although the mechanisms of resistance are not fully understood, this effect could be correlated to the property of drug efflux mechanisms carried out by chemoresistant cell lines [ 25 ].…”

“…In this regard, although the PI3K/Akt/cyclin D1 proteins are constitutively expressed in both cells, TCDD only induced these proteins in A2780 but not in resistant cells. This could be attributed to the property of drug efflux mechanisms carried out by chemoresistant cell lines [ 25 ].…”

Profiling the compendium of changes in Saccharomyces cerevisiae due to mutations that alter availability of the main methyl donor S-Adenosylmethionine

“…2019 ). Previous research has identified several multidrug exporters in human cells that exhibit upregulation in cells resistant to cisplatin ( Koshkin et al . 2021 ).…”

Automated identification and tracking of cells in Cytometry of Reaction Rate Constant (CRRC)

“…In the previous CRRC studies, imaging was performed with confocal laser-scanning fluorescence microscopy [ 12 , 25 , 26 ]. In the current work, we used epifluorescence microscopy with a Leica DMi8 high-throughput cell-imaging system.…”