Evaluating the relationship between cell viability and volatile organic compound production following DMSO treatment of cultured human cells.

Methylsulfinylmethane (dimethyl sulfoxide; DMSO) is widely used in clinical treatment and bioresearch. Moreover, there is bioconversion between methylsulfanylmethane (dimethyl sulfide; DMS), DMSO, and methylsulfonylmethane (DMSO2) in mammalian metabolism. Due to the real-time detection limits for volatile compounds, most research has focused on DMSO2 as a stable byproduct of DMSO. Therefore, details about the production of DMS as a byproduct of DMSO metabolism remain to be elucidated. Here, we report the characterization of trace-level volatile organic compounds (VOCs) produced following DMSO treatment of cultured human cells using an ultrasensitive vacuum ultraviolet photoionization mass spectrometer (VUV-PIMS). Using this approach, 24 h after DMSO treatment we detected 16.9 and 21 parts per billion by volume (ppbv) DMS in the atmosphere above the cells (headspace) within HeLa and 293T tissue culture flasks, respectively. When simultaneously exposed to 50 nM paclitaxel (PTX), 17.6 and 22.3 ppbv DMS were detected in the headspace of HeLa and 293T culture flasks, respectively. Nevertheless, at doses of PTX more or less than 50 nM, the detectable levels of DMS were reduced to as low as 8.4 ppbv. Our experimental results demonstrate that by co-administering 5 to 10 nM PTX with DMSO, it is possible to moderate the production of DMS considerably. However, at higher doses of PTX, increased apoptosis was observed that likely contributed to higher DMS production by cells.