Impact of genotypic and phenotypic differences in sarcoma models on the outcome of photochemical internalization (PCI) of bleomycin

Abstract

The low curative response to current treatment regimens for most soft tissue sarcomas indicates a strong need for alternative treatment strategies and predictive markers for treatment outcome. PCI (photochemical internalization) is a novel treatment strategy to translocate drugs into cytosol that otherwise would have been degraded in lysosomes. Two highly geno-and phenotypically different uterine and vulvar leiomyosarcoma cell lines, MES-SA and SK-LMS-1, were treated with bleomycin (BLM) activated by PCI (PCI). The MES-SA cells were much more sensitive to PCI than the SK-LMS-1 cells and the treatment induced a 7-8 fold higher increase in DNA double-strand breaks at the same dose of light as measure by γH2AX staining. A 3-fold higher induction of apoptosis and stronger activation of Bax and p21 was also measured in the P53WT MES-SA cells, compared to the P53mut SK-LMS-1 cells. The basal formation of reactive oxygen species (ROS) was 3-fold higher in SK-LMS-1 cells than in the MES-SA cells and SK-LMS-1 cells expressed glutathione peroxidase 1 (GPx1) and more superoxide dismutase 2 (SOD2) than the MES-SA cells. Glutathione depletion with the glutathione synthetase inhibitor buthionine sulfoximine increased the cytotoxic effect of the photochemical treatment (PDT) most strongly in the SK-LMS-1 cells, and reduced PCI-induced H2AX activation in the MES-SA cells, but not in the SK-LMS-1 cells. The results indicate PCI as a potential novel treatment strategy for soft tissue sarcomas, with antioxidant enzymes, in particular GPx1, and the P53 status as potential predictive markers for response to PCI.

Upregulated microRNA‐423‐5p promotes oxidative stress through targeting glutathione S‐transferase mu 1 in asthenozoospermia

“…GSS plays an antioxidant role by promoting GSH synthesis. Treatment with buthionine sulfoximine, the GSS inhibitor, increased the cytotoxic effect of photochemical treatment (PDT) most strongly in SK‐LMS‐1 cells (Olsen et al, 2017). GPX is an important enzyme, which is involved in GSH function.…”

Cytotoxic and Photocytotoxic Effects of Cercosporin on Human Tumor Cell Lines

“…The cells were incubated for 1 h in a 37°C humidified atmosphere (non CO 2 ), and thereafter, cell respiration was monitored by measurement of the oxygen consumption rate (OCR) with a Seahorse XFe96 Analyzer (Agilent, Santa Clara, CA). Cells were examined for their respiration and glycolytic activity by measuring the rate of extracellular acidification as described previously .…”

Predictive biomarkers for 5‐ALA‐PDT can lead to personalized treatments and overcome tumor‐specific resistances

“…31,32 In general, the sensitivity of cell lines to PDT was found to be variant, due to phenotypic and genotypic differences as also reported elsewhere. 33 Furthermore, there was no direct correlation between the intracellular amount of PpIX and 5-ALA-PDT cytotoxicity, across the cell lines (Figure S4). We further investigated these differential cytotoxicities delineated above for three Our experimental observations warranted the investigation of possible ways to sensitize the GBM cells to 5-ALA-PDT, especially since it is well established that 5-ALA-derived PpIX fluorescence is used to precisely guide the surgical resection of GBM and bladder lesions due to its high specificity.…”