Urciaga-Gutierrez Pedro Ivan, Franco-Topete Ramon Antonio, Bastidas-Ramirez Blanca Estela, Solorzano-Ibarra Fabiola, Rojas-Diaz Jose Manuel, Garcia-Barrientos Nadia Tatiana, Klimov-Kravtchenko Ksenia, Tellez-Bañuelos Martha Cecilia, Ortiz-Lazareno Pablo Cesar, Peralta-Zaragoza Oscar, Meneses-Acosta Angelica, Alejandre-Gonzalez Alan Guillermo, Bueno-Topete Miriam Ruth, Haramati Jesse, Del Toro-Arreola Susana
Instituto de Investigación en Enfermedades Crónico Degenerativas, Departamento de Biología Molecular y Genómica, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara 44340, Jalisco, Mexico.
Laboratorio de Patología, Departamento de Microbiología y Patología, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara 44340, Jalisco, Mexico.
Cancers (Basel). 2024 Sep 11;16(18):3126. doi: 10.3390/cancers16183126.
CMTM6 is a membrane protein that acts as a regulator of PD-L1, maintaining its expression on the cell surface, and can prevent its lysosome-mediated degradation. It is unknown if CMTM6 is present in the plasma of patients with cervical cancer, and if it has non-canonical subcellular localizations in cell lines derived from cervical cancer. Our objective was to determine whether CMTM6 is found in plasma derived from cervical cancer patients and its subcellular localization in cell lines. Patient plasma was separated into exosome-enriched, exosome-free, and total plasma fractions. The levels of CMTM6 in each fraction were determined using ELISA and Western blot. Finally, for the cellular model, HeLa, SiHa, CaSki, and HaCaT were used; the subcellular locations of CMTM6 were determined using immunofluorescence and flow cytometry. Soluble CMTM6 was found to be elevated in plasma from patients with cervical cancer, with a nearly three-fold increase in patients (966.27 pg/mL in patients vs. 363.54 pg/mL in controls). CMTM6 was preferentially, but not exclusively, found in the exosome-enriched plasma fraction, and was positively correlated with exosomal PD-L1; CMTM6 was identified in the membrane, intracellular compartments, and culture supernatant of the cell lines. These results highlight that CMTM6, in its various presentations, may play an important role in the biology of tumor cells and in immune system evasion.
CMTM6是一种膜蛋白，作为程序性死亡受体配体1（PD-L1）的调节剂，维持其在细胞表面的表达，并可防止其被溶酶体介导降解。目前尚不清楚CMTM6是否存在于宫颈癌患者的血浆中，以及它在源自宫颈癌的细胞系中是否具有非典型的亚细胞定位。我们的目的是确定CMTM6是否存在于宫颈癌患者的血浆中及其在细胞系中的亚细胞定位。将患者血浆分离为富含外泌体、无外泌体和总血浆部分。使用酶联免疫吸附测定（ELISA）和蛋白质免疫印迹法（Western blot）测定各部分中CMTM6的水平。最后，对于细胞模型，使用了人宫颈癌细胞系HeLa、SiHa、CaSki和人永生化角质形成细胞系HaCaT；使用免疫荧光和流式细胞术确定CMTM6的亚细胞定位。发现可溶性CMTM6在宫颈癌患者血浆中升高，患者体内几乎增加了三倍（患者为966.27 pg/mL，对照组为363.54 pg/mL）。CMTM6优先但并非唯一地存在于富含外泌体的血浆部分中，并且与外泌体PD-L1呈正相关；在细胞系的细胞膜、细胞内区室和培养上清液中鉴定到了CMTM6。这些结果表明，CMTM6的各种表现形式可能在肿瘤细胞生物学和逃避免疫系统中发挥重要作用。
