Doxorubicin-provoked increase of mitotic activity and concomitant drain of G0-pool in therapy-resistant BE(2)-C neuroblastoma

Abstract

In this study chemotherapy response in neuroblastoma (NB) was assessed for the first time in a transplantation model comprising non-malignant human embryonic microenvironment of pluripotent stem cell teratoma (PSCT) derived from diploid bona fide hESC. Two NB cell lines with known high-risk phenotypes; the multi-resistant BE(2)-C and the drug sensitive IMR-32, were transplanted to the PSCT model and the tumour growth was exposed to single or repeated treatments with doxorubicin, and thereafter evaluated for cell death, apoptosis, and proliferation. Dose dependent cytotoxic effects were observed, this way corroborating the experimental platform for this type of analysis. Notably, analysis of doxorubicin-resilient BE(2)-C growth in the PSCT model revealed an unexpected 1,5-fold increase in Ki67-index (p<0.05), indicating that non-cycling (G0) cells entered the cell cycle following the doxorubicin exposure. Support for this notion was obtained also in vitro. A pharmacologically relevant dose (1μM) resulted in a marked accumulation of Ki67 positive BE(2)-C cells (p<0.0001), as well as a >3-fold increase in active cell cycle (i.e. cells positive staining for PH3 together with incorporation of EdU) (p<0.01). Considering the clinical challenge for treating high-risk NB, the discovery of a therapy-provoked growth-stimulating effect in the multi-resistant and p53-mutated BE(2)-C cell line, but not in the drug-sensitive p53wt IMR-32 cell line, warrants further studies concerning generality and clinical significance of this new observation.

Heterogeneities in Cell Cycle Checkpoint Activation Following Doxorubicin Treatment Reveal Targetable Vulnerabilities in TP53 Mutated Ultra High-Risk Neuroblastoma Cell Lines

“…The flow cytometry data showed, for all cell lines, high, but not full, resistance to doxo induced apoptosis Table 1, in agreement with previous literature and a proposed role of p53 in the induction of cell death [11]. Furthermore, a dose-dependent decrease of cells in G0/G1 (2N-fraction) and an accumulation in S-and/or G2/M-phase was observed in all cell lines following either 0.1 or 1 µM doxo, in agreement with the notion that cells with a dysfunctional p53 pathway generally fail to arrest at the G1/S-checkpoint [29,30]. However, the cell response was dose-dependent, where for example the two cell lines, SK-N-AS and Kelly, which showed preferred accumulation in S-phase following 1 µM doxo, instead had preferred accumulation in G2/M-phase following 0.1 µM doxo.…”

The role of exogenous epidermal growth factor on Ki-67 proliferation marker expression in the submandibular salivary gland of albino rats receiving doxorubicin

“…Saggar & Tannok (2015) noted that DXR resulted in the highest increase in Ki-67 cells in reoxygenated surviving hypoxic cells. Hultman et al (2018) found that post DXR treatment the BE (2)-C (neuroblastoma cell line derived from human bone marrow) tumor growth presented a remarkable increase in Ki-67-index (from 43% to 64%; p<0.01), thus indicating a move towards cycling cells by application of DXR. Tredan et al (2007) previously determined the same hypothesis and found in vitro that quiescent (G0) tumor cells enter cell cycle after DXR treatment.…”

“… Hultman et al . (2018) found that post DXR treatment the BE (2)-C (neuroblastoma cell line derived from human bone marrow) tumor growth presented a remarkable increase in Ki-67-index (from 43% to 64%; p<0.01), thus indicating a move towards cycling cells by application of DXR.…”

Lactic Acidosis Interferes With Toxicity of Perifosine to Colorectal Cancer Spheroids: Multimodal Imaging Analysis

“…Therefore, perifosine might improve the supply of nutrients to the spheroid cells ( Supplementary Image 9). The chemotherapyinduced cell proliferation has been observed previously and might contribute to chemotherapy failure (79,80). However, perifosine downregulates Ki-67 during 48 and 72 h, and this effect is spatially restricted to the most peripheral cell layers 0-50 µm from the spheroid boundary.…”