Prado-Celis Linley P, Zamora-Cárdenas Rodrigo, Alamilla Javier, Sánchez-Pastor Enrique A, Ferrer Tania, Moreno-Galindo Eloy G, Navarro-Polanco Ricardo A
Centro Universitario de Investigaciones Biomédicas "CUIB", Universidad de Colima, Colima, Colima, Mexico.
Consejo Nacional de Humanidades, Ciencia y Tecnología (CONAHCYT), Universidad de Colima, Colima, Mexico.
PLoS One. 2025 May 13;20(5):e0323554. doi: 10.1371/journal.pone.0323554. eCollection 2025.
Multiple investigations have shown that the different types of cannabinoids, phytocannabinoids, synthetic cannabinoids, and endocannabinoids, possess antiproliferative and anticancer properties. The cannabinoid type-2 receptor (CB2R) has been proposed as a central player in tumor progression and has been correlated with the aggressiveness of breast cancer. Using immunocytochemistry and confocal microscopy, in the present work, we studied the expression level and subcellular localization of CB2R in two human triple-negative breast cancer (TNBC) cell lines, corresponding to early (stage I, HCC-1395) and metastatic (MDA-MB-231) stages, and they were compared with a non-tumoral mammary epithelial cell line (MCF-10A). We found that although CB2R was detected at the plasma membrane, it was mainly localized intracellularly, with ~40-fold higher expression in both TNBC cell lines than in MCF-10A (P < 0.0001). Notably, double staining with DAPI or with the nucleoli-specific fluorescent marker (3xnls-mTurquoise2) showed that most of the CB2R overexpressed in the nucleoli of cancer cells. This finding is supported by the fact that CB2R expression was markedly lower in mitotic cells compared to interphase cells (P < 0.0001). Interestingly, exposure of cancer cells to the specific agonist HU-308 reversed the nucleolar sequestration of CB2R while increasing the presence of the receptor in the nucleoplasm and cytoplasm (P < 0.0001). In addition, we found that this agonist reduced both the cell migration (P < 0.05-0.0001) and proliferation (P < 0.001) of TNBC cells. It remains to determine the function and signaling ability of CB2R in the nucleolus. Although our study only includes cell lines (tumoral and non-tumoral), we consider that this feature of nucleolar sequestration of CB2R could be a potential diagnostic marker for TNBC from the early stage.
多项研究表明，不同类型的大麻素，包括植物大麻素、合成大麻素和内源性大麻素，具有抗增殖和抗癌特性。大麻素2型受体（CB2R）被认为是肿瘤进展的关键因素，并且与乳腺癌的侵袭性相关。在本研究中，我们使用免疫细胞化学和共聚焦显微镜技术，研究了CB2R在两种人三阴性乳腺癌（TNBC）细胞系中的表达水平和亚细胞定位，这两种细胞系分别对应早期（I期，HCC-1395）和转移期（MDA-MB-231），并将它们与非肿瘤性乳腺上皮细胞系（MCF-10A）进行比较。我们发现，虽然在质膜上检测到了CB2R，但它主要定位于细胞内，在两种TNBC细胞系中的表达均比MCF-10A高约40倍（P < 0.0001）。值得注意的是，用DAPI或核仁特异性荧光标记物（3xnls-mTurquoise2）进行双重染色显示，癌细胞核仁中过表达了大部分CB2R。这一发现得到了以下事实的支持：与间期细胞相比，有丝分裂细胞中CB2R的表达明显较低（P < 0.0001）。有趣的是，将癌细胞暴露于特异性激动剂HU-308可逆转CB2R的核仁隔离，同时增加该受体在核质和细胞质中的存在（P < 0.0001）。此外，我们发现该激动剂降低了TNBC细胞的迁移能力（P < 0.05 - 0.0001）和增殖能力（P < 0.001）。CB2R在核仁中的功能和信号传导能力仍有待确定。虽然我们的研究仅包括细胞系（肿瘤性和非肿瘤性），但我们认为CB2R的核仁隔离这一特征可能是TNBC早期潜在的诊断标志物。
