Epigeneres Biotech Pvt Ltd, Todi Mill Compound, Senapati Bapat Marg, Lower Parel, 400013, Mumbai, India.
Barts Health NHS Trust, Englands, UK.
Stem Cell Rev Rep. 2024 May;20(4):857-880. doi: 10.1007/s12015-024-10694-7. Epub 2024 Mar 8.
Multiple theories exist to explain cancer initiation, although a consensus on this is crucial for developing effective therapies. 'Somatic mutation theory' suggests that mutations in somatic cells during DNA repair initiates cancer but this concept has several attached paradoxes. Research efforts to identify quiescent cancer stem cells (CSCs) that survive therapy and result in metastasis and recurrence have remained futile. In solid cancers, CSCs are suggested to appear during epithelial-mesenchymal transition by the dedifferentiation and reprogramming of epithelial cells. Pluripotent and quiescent very small embryonic-like stem cells (VSELs) exist in multiple tissues but remain elusive owing to their small size and scarce nature. VSELs are developmentally connected to primordial germ cells, undergo rare, asymmetrical cell divisions and are responsible for the regular turnover of cells to maintain tissue homeostasis throughout life. VSELs are directly vulnerable to extrinsic endocrine insults because they express gonadal and gonadotropin hormone receptors. VSELs undergo epigenetic changes due to endocrine insults and transform into CSCs. CSCs exhibit genomic instability and develop mutations due to errors during DNA replication while undergoing excessive proliferation and clonal expansion to form spheroids. Thus tissue-resident VSELs offer a connection between extrinsic insults and variations in cancer incidence reported in various body tissues. To conclude, cancer is indeed a stem cell disease with mutations occurring as a consequence. In addition to immunotherapy, targeting mutations, and Lgr5 + organoids for developing new therapeutics, targeting CSCs (epigenetically altered VSELs) by improving their niche and epigenetic status could serve as a promising strategy to treat cancer.
存在多种解释癌症发生的理论,但对于开发有效的治疗方法来说,达成共识至关重要。“体细胞突变理论”认为,在 DNA 修复过程中体细胞发生突变会引发癌症,但这一概念存在几个相关悖论。尽管研究人员一直努力寻找在治疗后存活并导致转移和复发的静止癌症干细胞 (CSC),但迄今仍未成功。在实体瘤中,CSC 被认为是通过上皮-间充质转化,由上皮细胞去分化和重编程而出现的。多能和静止的非常小胚胎样干细胞 (VSEL) 存在于多种组织中,但由于其体积小且数量稀少,因此难以捉摸。VSEL 与原始生殖细胞在发育上有关联,经历罕见的不对称细胞分裂,负责维持整个生命周期组织内稳态的细胞常规更新。VSEL 直接易受外在内分泌干扰,因为它们表达性腺和促性腺激素受体。VSEL 会因内分泌干扰而发生表观遗传变化,并转化为 CSC。CSC 表现出基因组不稳定性,并因在 DNA 复制过程中发生错误而产生突变,同时过度增殖和克隆扩增形成球体。因此,组织驻留的 VSEL 为外在刺激与各种身体组织中报告的癌症发病率变化之间提供了联系。总之,癌症确实是一种干细胞疾病,突变是其后果之一。除了免疫疗法、针对突变和 Lgr5+类器官开发新的治疗方法外,通过改善其生态位和表观遗传状态来靶向 CSC(表观遗传改变的 VSEL),可能是治疗癌症的一种有前途的策略。