Head and Neck Cancer Cell Death due to Mitochondrial Damage Induced by Reactive Oxygen Species from Nonthermal Plasma‐Activated Media: Based on Transcriptomic Analysis

Abstract

Mitochondrial targeted therapy is a next-generation therapeutic approach for cancer that is refractory to conventional treatments. Mitochondrial damage caused by the excessive accumulation of reactive oxygen species (ROS) is a principle of mitochondrial targeted therapy. ROS in nonthermal plasma-activated media (NTPAM) are known to mediate anticancer effects in various cancers including head and neck cancer (HNC). However, the signaling mechanism of HNC cell death via NTPAM-induced ROS has not been fully elucidated. This study evaluated the anticancer effects of NTPAM in HNC and investigated the mechanism using transcriptomic analysis. The viability of HNC cells decreased after NTPAM treatment due to enhanced apoptosis. A human fibroblast cell line and three HNC cell lines were profiled by RNA sequencing. In total, 1 610 differentially expressed genes were identified. Pathway analysis showed that activating transcription factor 4 (ATF4) and C/EBP homologous protein (CHOP) were upstream regulators. Mitochondrial damage was induced by NTPAM, which was associated with enhancements of mitochondrial ROS (mtROS) and ATF4/CHOP regulation. These results suggest that NTPAM induces HNC cell death through the upregulation of ATF4/CHOP activity by damaging mitochondria via excessive mtROS accumulation, similar to mitochondrial targeted therapy.

Open Questions in Cold Atmospheric Plasma Treatment in Head and Neck Cancer: A Systematic Review

“…A total of 47 full-text articles were finally evaluated, and 23 were subsequently excluded [ 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 ] for the reasons listed in Table 1 . A total of 24 studies [ 5 , 6 , 15 , 23 , 36 , 37 , 38 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 ] fulfilled the selection criteria of the present review and were included for qualitative analysis. The value of the k-statistic was 0.78, which indicates an excellent level of agreement between reviewers…”

“… Nineteen [ 5 , 6 , 23 , 36 , 37 , 38 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 ] preclinical studies investigated the CAP in vitro effect on different HNC cell lines, and 3 [ 73 , 74 , 77 ] out of those 19 articles conducted in vivo experiments on an animal model ( Table 2 ); Five [ 15 , 84 , 85 , 86 , 87 ] clinical studies were conducted on human beings ( Table 3 ). …”

“…Only in one study [ 23 ] was there inadequate information about the “condition of cell culture before treatment” domain, while three other studies lacked “multiple experiments performed” evidence. All three in vivo animal studies [ 73 , 74 , 77 ] were at high risk of bias based on SYRCLE features. Only three domains, such as “sequence generation”, “baseline characteristics”, and “selective outcome reporting”, were adequate in all the studies.…”

“…Only three domains, such as “sequence generation”, “baseline characteristics”, and “selective outcome reporting”, were adequate in all the studies. “Blinding” in outcome assessment was adequate only in Kang et al [ 73 ], while “incomplete outcome data” was adequate only in the Oh et al study [ 77 ]. Information about the following domains, such as “allocation concealment”, “random housing”, “blinding”, “random outcome assessment”, and “other sources of bias”, were not retrievable.…”

“…The 19 in vitro studies [ 5 , 6 , 23 , 36 , 37 , 38 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 ] evaluated the CAP effect on various HNC cell lines ( Figure 4 ) arising at specific anatomical sites and representative of specific cancers, such as the human floor of the mouth squamous cell carcinoma (AMC-HN6, Ho-1-u-1), human tongue squamous cell carcinoma (CAL-27, HNO-97, HSC-3, HSC-4, OSC-19, SAS, SCC-15, SCC-25, SCC-4), human oral cavity squamous cell carcinoma (HSC-2, SCC-QLL1), human oral retromolar trigone cavity squamous cell carcinoma (SCC-1483), human hypopharynx squamous cell carcinoma (FaDu, SNU-1041), human laryngeal squamous cell carcinoma (JHU-022, JHU-029, SNU-899, SNU-1076), human pharyngeal squamous cell carcinoma (Detroit-562), human undifferentiated carcinoma of the parotid gland (AMC-HN-9), and normal oral cavity cell lines: human gingival fibroblasts (HGF-1), human normal oral keratinocytes (NOKsi) and normal human floor of the mouth keratinocytes (OKF6/T).…”