Chemical and molecular bases of dome formation in human colorectal cancer cells mediated by sulphur compounds from Cucumis melo var. conomon

Abstract

Colorectal cancer was the third most commonly diagnosed malignant tumor and the fourth leading cause of cancer deaths worldwide in 2012. A human colorectal cancer cell line, RCM-1, was established from a colon cancer tissue diagnosed as a well-differentiated rectum adenocarcinoma. RCM-1 cells spontaneously form "domes" (formerly designated "ducts") resembling villiform structures. Two sulphur-containing compounds from Cucumis melo var. conomon (Katsura-uri, or Japanese pickling melon), referred to as

Methylthioacetic acid, a derivative of aroma compounds from <i>Cucumis melo</i> var. <i>conomon</i> dose-dependently triggers differentiation and apoptosis of RCM-1 human colorectal cancer cells

“…RCM-1 cells were cultured as previously described (Kamimura et al, 2020), with minor modifications. Briefly, culture volumes were changed according to the experimental purpose; 1 × 10 5 cells were seeded in a 96-well plate as a small-scale culture for the dome formation, cell viability, DNA fragmentation, and caspase activity assays, while 5.8 × 10 5 cells were seeded in a 24-well plate for the trypan blue exclusion assay and immunoblotting.…”

“…The dome formation assay was performed according to Kamimura et al (2020). The domes were observed and counted under an inverted microscope (IX73, Olympus Corp., Tokyo, Japan).…”

“…T9300A, Takara Bio Inc., Shiga, Japan). Immunoblotting was performed as described by Kamimura et al (2020). The primary antibody reactions were performed using the following antibodies appropriately diluted to each target protein: anti-cleaved poly(ADP-ribose) polymerase (PARP; 1:1,000, #5625, Cell Signaling Technology, Inc., MA, USA), antidipeptidyl peptidase 4 (DPP4; 1:1,000, #67138, Cell Signaling Technology), anti-Krüppel-like factor 4 (KLF4; 1:500, #12173, Cell Signaling Technology), anti-villin (1:500, 66096-1-Ig, Proteintech Group, Inc., IL, USA), and anti-β-actin (1:10,000, 66009-1-Ig, Proteintech).…”

“…We used the number of domes formed in the RCM-1 cell culture as a guide for screening to isolate the above-mentioned MTPE and MTAE from Katsura-uri and piperitenone oxide (PO) from spearmint (Mentha spicata) as well (Nakamura et al, 2008(Nakamura et al, , 2010(Nakamura et al, , 2014. Furthermore, we identified methylthioacetic acid (MTA), an acid-hydrolyzed derivative of MTAE (Aoi et al, 2015) to have the most potent dome-inducing activity among the 37 MTPE and MTAE analogs and it is involved in the cell cycle arrest of RCM-1 (Kamimura et al, 2020). On the other hand, the physiological and molecular properties of MTA remain unknown.…”

OMICS Applications for Medicinal Plants in Gastrointestinal Cancers: Current Advancements and Future Perspectives

“…Administration of methylthioacetic acid (MTA) extracted from Cucumis melo L. facilitated the formation of multicellular and cystic structures (termed domes) in human CRC RCM-1 cells, which is a promising differentiation therapy that aims to alleviate cancer malignancy without massacring normal cells. A microarray demonstrated that MTA-induced dome formation is at least partially associated with the downregulation of cyclin E2 and CDC25A, two crucial genes involved in G1 phase cell cycle control (Kamimura et al, 2020).…”