Dolma Lobsang, Patterson Mary I, Banyard Antonia, Hall Callum, Bell Steven, Breitwieser Wolfgang, Sahoo Sudhakar, Weightman John, Gil Maria Pazos, Ashton Garry, Behan Caron, Fullard Nicola, Williams Lewis D, Muller Patricia Aj
Biosciences, Durham University, Durham, UK.
Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK.
Cell Death Discov. 2025 Jul 1;11(1):288. doi: 10.1038/s41420-025-02582-x.
Previously, we identified that mutant p53 expression in cancer cells promotes engulfment of neighbouring cancer cells to form cell-in-cell (CIC) structures. This process gave mutant p53 cells an advantage in tumour formation in mouse xenograft experiments. TP53 can be found mutated at nearly every amino acid in cancers and mutant p53 expression is associated with various GOF (Gain-of-function) processes, including cancer cell invasion, metastasis, stemness and drug resistance. In the current manuscript, we identified SH3BGRL (Src homology 3 binding glutamate rich protein like) as a mutant p53-regulated gene and investigated to what extent SH3BGRL expression and cell engulfment are responsible for mutant p53-dependent anchorage-independent growth and chemoresistance. We demonstrate that mutant p53 expression drives cell engulfment in which the mutant p53 host cell moves in the direction of the target internal cell to form CIC structures. This is therefore more reminiscent of cell engulfment rather than cell entosis, in which cells invade into host cells. Using NGS (Next Generation Sequencing), we identified novel target genes of mutant p53 and demonstrate that cell engulfment requires SH3BGRL expression. We generated mutant p53 and p53 KO cell lines that stably overexpressed SH3BGRL and determined that SH3BGRL promotes etoposide resistance in mutant p53 cells and anchorage-independent growth independent of mutant p53 expression. Through FACS sorting of pure cell engulfing (CIC) populations, we could also show that engulfing cells have an enhanced etoposide resistance. These data suggest that SH3BGRL and cell engulfment are required for certain GOFs of mutant p53.
此前，我们发现癌细胞中突变型p53的表达会促进对邻近癌细胞的吞噬，从而形成细胞内细胞（CIC）结构。在小鼠异种移植实验中，这一过程赋予了突变型p53细胞在肿瘤形成方面的优势。TP53在癌症中几乎每个氨基酸位点都可能发生突变，且突变型p53的表达与多种功能获得（GOF）过程相关，包括癌细胞侵袭、转移、干性和耐药性。在当前的论文中，我们鉴定出SH3BGRL（Src同源3结合富含谷氨酸蛋白样）为一个受突变型p53调控的基因，并研究了SH3BGRL的表达和细胞吞噬在多大程度上导致了依赖于突变型p53的锚定非依赖性生长和化疗耐药性。我们证明，突变型p53的表达驱动细胞吞噬，其中突变型p53宿主细胞朝着目标内部细胞的方向移动以形成CIC结构。因此，这更类似于细胞吞噬而非细胞内吞，细胞内吞是指细胞侵入宿主细胞。通过二代测序（NGS），我们鉴定出了突变型p53的新靶基因，并证明细胞吞噬需要SH3BGRL的表达。我们构建了稳定过表达SH3BGRL的突变型p53和p53基因敲除细胞系，并确定SH3BGRL可促进突变型p53细胞对依托泊苷的耐药性以及不依赖于突变型p53表达的锚定非依赖性生长。通过对纯细胞吞噬（CIC）群体进行荧光激活细胞分选（FACS），我们还可以表明吞噬细胞具有增强的依托泊苷耐药性。这些数据表明，SH3BGRL和细胞吞噬是突变型p53某些功能获得所必需的。
