Sung-Hun Woo, Bohee Kim, Sung Hoon Kim, Byung Chul Jung, Yongheum Lee & Yoon Suk Kim. BMB Reports 2022;55:148-53. https://doi.org/10.5483/BMBRep.2022.55.3.119

Interferon (IFN)-β and/or tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) secreted by adipose tissue-derived mesenchymal stem cells (ASCs) have been proposed as key mechanistic factors in anti-cancer efficacy in lung cancer and breast cancer cells, where they act through paracrine signaling. We hypothesized that IFN-β and TRAIL produced by ASCs suppress proliferation of hepatocellular carcinoma cells (HCCs). The present study evaluated the anti-cancer effects of ASCs on HCCs in vitro. We found that indirect co-culture with ASCs diminished growth of Huh7 hepatocellular carcinoma cells with increased protein levels of p53/p21 and phosphorylated STAT1 (pSTAT1), without apoptosis. Treatment with ASC-conditioned medium (ASC-CM) also decreased growth of Huh7 cells through elevated p53/p21 and pSTAT1 signaling. ASC-CM-mediated inhibition of cell growth was neutralized in Huh7 cells treated with anti-IFN-β antibody compared to that in ASC-CM-treated Huh7 cells incubated with an anti-TRAIL antibody. Treatment with JAK1/JAK2 inhibitors recovered inhibition of growth in Huh7 cells incubated in ASC-CM or IFN-β via down-regulation of pSTAT1/p53/p21. However, treatment of IFN-β resulted in no alterations in resistance of Huh7 cells to TRAIL. Our findings suggest that ASCs decrease growth through activated STAT1-mediated p53/p21 by IFN-β, but not TRAIL, in Huh7 cells.

Characterization of cellular dielectrophoretic (DEP) behaviors, when cells are exposed to an alternating current (AC) electric field of varying frequency, is fundamentally important to many applications using dielectrophoresis. However, to date, that characterization has been performed with monotonically increasing or decreasing frequency, not with successive increases and decreases, even though cells might behave differently with those frequency modulations due to the nonlinear cellular electrodynamic responses reported in previous works. In this report, we present a method to trace the behaviors of numerous cells simultaneously at the single-cell level in a simple, robust manner using dielectrophoretic tweezers-based force spectroscopy. Using this method, the behaviors of more than 150 cells were traced in a single environment at the same time, while a modulated DEP force acted upon them, resulting in characterization of nonlinear DEP cellular behaviors and generation of different cross-over frequencies in living cells by modulating the DEP force. This study demonstrated that living cells can have non-linear di-polarized responses depending on the modulation direction of the applied frequency as well as providing a simple and reliable platform from which to measure a cellular cross-over frequency and characterize its nonlinear property.

Byung Chul Jung, Sung-Hun Woo , Sung Hoon Kim & Yoon Suk Kim. BMB Reports 2024;57:104-9. https://doi.org/10.5483/BMBRep.2023-0225

Background/Aim: Gefitinib exhibits anticancer activity against cervical cancer cells via anoikis, a type of apoptosis induced by cell detachment from the extracellular matrix. Previous studies have reported that Parkin expression affects the efficacy of anticancer drugs. However, the impact of Parkin expression on the therapeutic effects of gefitinib in human cervical cancer remains unclear. Thus, this study aimed to evaluate whether Parkin over-expression improves the therapeutic effects of gefitinib against HeLa cervical cancer cells. Materials and Methods: Cell viability and apoptotic death of HeLa cells were measured by trypan blue dye exclusion assay and flow cytometry. Cell detachment, adhesion, spreading, and cell-cell interaction were observed by inverted microscopy. Alteration of adhesion-related molecules was evaluated by confocal microscopy and western blot assay. Results: Parkin expression potentiated gefitinib-induced cell detachment by affecting the organization of the actin cytoskeleton. In addition, Parkin expression induced a further reduction in the reattachment of and interaction between detached cells. The therapeutic efficacy of low-dose gefitinib combined with Parkin expression was equivalent to that of high-dose gefitinib alone. Conclusion: Parkin expression promotes gefitinib-induced anoikis, consequently increasing the efficacy of gefitinib against HeLa human cervical cancer cells. Based on our results, we propose that Parkin can be used to increase the anti-cancer effect of gefitinib on cervical cancer cells.

Background/Aim: Pulsed electromagnetic field (PEMF) stimulation enhances the efficacy of several anticancer drugs. Doxorubicin is an anticancer drug used to treat various types of cancer, including breast cancer. However, the effect of PEMF stimulation on the efficacy of doxorubicin and the underlying mechanisms remain unclear. Thus, this study aimed to investigate the effect of PEMF stimulation on the anticancer activity of doxorubicin in MDA-MB-231 human breast cancer cells. Materials and Methods: MDA-MB-231 cells were seeded and allowed to incubate for 48 h. The cells were treated with doxorubicin, cisplatin, 5-fluorouracil, or paclitaxel for 48 h. Subsequently, the cells were stimulated with a 60-min PEMF session thrice a day (with an interval of 4 h between each session) for 24 or 48 h. Cell viability was assessed by trypan blue dye exclusion assay and cell-cycle analysis was analyzed by flow cytometry. Molecular mechanisms involved in late G₂ arrest were confirmed by a western blot assay and confocal microscopy. Results: MDA-MB-231 cells treated with a combination of doxorubicin and PEMF had remarkably lower viability than those treated with doxorubicin alone. PEMF stimulation increased doxorubicin-induced cell-cycle arrest in the late G₂ phase by suppressing cyclin-dependent kinase 1 (CDK1) activity through the enhancement of myelin transcription factor 1 (MYT1) expression, cell division cycle 25C (CDC25C) phosphorylation, and stratifin (14-3-3σ) expression. PEMF also increased doxorubicin-induced DNA damage by inhibiting DNA topoisomerase II alpha (TOP2A). Conclusion: These findings support the use of PEMF stimulation as an adjuvant to strengthen the antiproliferative effect of doxorubicin on breast cancer cells.