In-Vivo Fusion of Human Cancer and Hamster Stromal Cells Permanently Transduces and Transcribes Human DNA

After demonstrating, with karyotyping, polymerase chain reaction (PCR) and fluorescence in-situ hybridization, the retention of certain human chromosomes and genes following the spontaneous fusion of human tumor and hamster cells in-vivo, it was postulated that cell fusion causes the horizontal transmission of malignancy and donor genes. Here, we analyzed gene expression profiles of 3 different hybrid tumors first generated in the hamster cheek pouch after human tumor grafting, and then propagated in hamsters and in cell cultures for years: two Hodgkin lymphomas (GW-532, GW-584) and a glioblastoma multiforme (GB-749). Based on the criteria of MAS 5.0 detection P-values ≤0.065 and at least a 2-fold greater signal expression value than a hamster melanoma control, we identified 3,759 probe sets (ranging from 1,040 to 1,303 in each transplant) from formalin-fixed, paraffin-embedded sections of the 3 hybrid tumors, which unambiguously mapped to 3,107 unique Entrez Gene IDs, representative of all human chromosomes; however, by karyology, one of the hybrid tumors (GB-749) had a total of 15 human chromosomes in its cells. Among the genes mapped, 39 probe sets, representing 33 unique Entrez Gene IDs, complied with the detection criteria in all hybrid tumor samples. Five of these 33 genes encode transcription factors that are known to regulate cell growth and differentiation; five encode cell adhesion- and transmigration-associated proteins that participate in oncogenesis and/or metastasis and invasion; and additional genes encode proteins involved in signaling pathways, regulation of apoptosis, DNA repair, and multidrug resistance. These findings were corroborated by PCR and reverse transcription PCR, showing the presence of human alphoid (α)-satellite DNA and the F11R transcripts in additional tumor transplant generations. We posit that in-vivo fusion discloses genes implicated in tumor progression, and gene families coding for the organoid phenotype. Thus, cancer cells can transduce adjacent stromal cells, with the resulting progeny having permanently transcribed genes with malignant and other gene functions of the donor DNA. Using heterospecific in-vivo cell fusion, genes encoding oncogenic and organogenic traits may be identified.

研究人员通过核型分析、聚合酶链式反应（polymerase chain reaction, PCR）及荧光原位杂交（fluorescence in-situ hybridization）证实，体内人肿瘤细胞与仓鼠细胞发生自发融合后，部分人类染色体与基因得以保留；据此提出假说：细胞融合可导致恶性表型与供体基因发生水平传递。本研究对3种不同的杂交肿瘤进行基因表达谱分析——这些杂交肿瘤首先通过将人肿瘤细胞移植至仓鼠颊囊生成，随后在仓鼠体内及细胞培养中传代多年，分别为2例霍奇金淋巴瘤（GW-532、GW-584）与1例多形性胶质母细胞瘤（GB-749）。基于MAS 5.0算法检测P值≤0.065、且信号表达值至少较仓鼠黑色素瘤对照高2倍的筛选标准，我们从3种杂交肿瘤的福尔马林固定石蜡包埋切片中鉴定出3759个探针集（每个移植样本的探针集数量介于1040至1303之间），这些探针集可明确匹配至3107个独特的Entrez基因ID（Entrez Gene IDs），覆盖所有人类染色体；但核型分析显示，其中1例杂交肿瘤（GB-749）的细胞中共包含15条人类染色体。在上述匹配的基因中，有39个探针集（对应33个独特的Entrez基因ID）在所有杂交肿瘤样本中均符合上述检测标准。这33个基因中，5个编码已知可调控细胞生长与分化的转录因子；5个编码参与肿瘤发生、转移及侵袭的细胞黏附与跨迁移相关蛋白；其余基因则分别编码参与信号通路、细胞凋亡调控、DNA修复及多药耐药的蛋白。上述发现通过PCR及逆转录PCR（reverse transcription PCR）得到验证：在额外的肿瘤移植传代样本中，可检测到人类α卫星DNA（human alphoid (α)-satellite DNA）及F11R转录本（F11R transcripts）。我们提出，体内细胞融合可揭示与肿瘤进展相关的基因，以及编码类器官表型的基因家族。据此，癌细胞可转导邻近的基质细胞，最终产生的子代细胞可永久转录供体DNA所携带的恶性及其他功能基因。利用异种体内细胞融合模型，可鉴定出编码致瘤与器官发生相关性状的基因。