Ito Soma, Chambers James K, Sumi Ayumi, Omachi Tetsuo, Haritani Makoto, Nakayama Hiroyuki, Uchida Kazuyuki
The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
Patho-Labo, Ito, Japan.
Vet Pathol. 2023 Jan;60(1):21-34. doi: 10.1177/03009858221139197. Epub 2022 Nov 17.
The involvement of papillomavirus type 2 (FcaPV2) in feline Merkel cell carcinoma (MCC) has been previously hypothesized. In this study, the expression and localization of FcaPV2 oncogene mRNA, the integration of FcaPV2 genes, and mutations in feline MCC were examined by RNAscope in situ hybridization (ISH), whole genome sequencing (WGS), and Sanger DNA sequencing, respectively. Furthermore, the morphological and molecular characteristics of FcaPV2-positive (FMX-MCC01) and FcaPV2-negative (AS-MCC01) MCC cell lines were compared in vitro and in vivo using immunofluorescence, ISH, xenotransplantation into mice, and immunohistochemistry. ISH for FcaPV2 detected viral RNA in 18/21 FcaPV2-positive MCC and not in 1/1 FcaPV2-negative MCC. WGS of 2 FcaPV2-positive cases revealed the integration of FcaPV2 genes in both cases. In cultured cells and xenograft tissues of FMX-MCC01, most cells were positive for E6/E7 by ISH and p16, a few cells were positive for the retinoblastoma protein (pRb), and all cells were negative for p53. In cultured cells and xenograft tissues of AS-MCC01, all cells were negative for p16, most cells were positive for pRb, and some cells were positive for p53. Missense mutations in were identified in 8/10 FcaPV2-positive and 1/1 FcaPV2-negative MCC. These results suggest that the expression of integrated FcaPV2 oncogenes might be associated with reduced expression of the tumor suppressor proteins pRb and p53 and might contribute to the development of feline MCC. On the other hand, mutations may be involved in both FcaPV2-positive and FcaPV2-negative MCC tumorigenesis.
先前曾推测2型乳头瘤病毒（FcaPV2）与猫默克尔细胞癌（MCC）有关。在本研究中，分别通过RNAscope原位杂交（ISH）、全基因组测序（WGS）和桑格DNA测序检测了FcaPV2癌基因mRNA的表达和定位、FcaPV2基因的整合以及猫MCC中的突变。此外，使用免疫荧光、ISH、小鼠异种移植和免疫组织化学在体外和体内比较了FcaPV2阳性（FMX-MCC01）和FcaPV2阴性（AS-MCC01）MCC细胞系的形态和分子特征。FcaPV2的ISH检测到18/21例FcaPV2阳性MCC中有病毒RNA，而1/1例FcaPV2阴性MCC中未检测到。2例FcaPV2阳性病例的WGS显示两例均有FcaPV2基因整合。在FMX-MCC01的培养细胞和异种移植组织中，大多数细胞ISH检测E6/E7和p16呈阳性，少数细胞视网膜母细胞瘤蛋白（pRb）呈阳性，所有细胞p53均呈阴性。在AS-MCC01的培养细胞和异种移植组织中，所有细胞p16均呈阴性，大多数细胞pRb呈阳性，一些细胞p53呈阳性。在8/10例FcaPV2阳性和1/1例FcaPV2阴性MCC中鉴定到错义突变。这些结果表明，整合的FcaPV2癌基因的表达可能与肿瘤抑制蛋白pRb和p53的表达降低有关，并可能促进猫MCC的发生。另一方面，错义突变可能参与FcaPV2阳性和FcaPV2阴性MCC的肿瘤发生。
