Biology subjects

Thevanesan, C.

Publications and source records attributed to Thevanesan, C..

3 recordsLinked to original sources

bioRxiv2022

Transcriptional signals of dedifferentiation in human cancer

As normal cells transform into cancers, their cell state changes (or "dedifferentiates"), which may drive cancer cells into a stem-like or more primordial, foetal or embryonic cell state. Here, we used single cell atlases to study dedifferentiation in transcriptional terms across a wide spectrum of adult and childhood cancers. At the level of the whole transcriptome, we find that adult cancers rarely return to an embryonic state, but rather that a foetal state is a near-universal feature of childhood cancers. We extend these bulk transcriptomic findings to a single cell resolution analysis of colorectal and liver cancers, confirming the lack of reversion to a primordial state in adult tumours and the retention of foetal signals in childhood cancers. Our findings provide a nuanced picture of dedifferentiation in these two groups of neoplasms, indicating cancer-specific rather than universal patterns of dedifferentiation pervade adult epithelial cancers.

cancer biology↗

bioRxiv2020

Tumor to normal single cell mRNA comparisons reveal a pan-neuroblastoma cancer cell

Neuroblastoma is an embryonal childhood cancer that arises from aberrant development of the neural crest, mostly within the fetal adrenal medulla. It is not established what developmental processes neuroblastoma cancer cells represent. Here, we sought to reveal the phenotype of neuroblastoma cancer cells by comparing cancer (n=16,591) with fetal adrenal single cell transcriptomes (n=57,972). Our principal finding was that the neuroblastoma cancer cell resembled fetal sympathoblasts, but no other fetal adrenal cell type. The sympathoblastic state was a universal feature of neuroblastoma cells, transcending cell cluster diversity, individual patients and clinical phenotypes. We substantiated our findings in 652 neuroblastoma bulk transcriptomes and by integrating canonical features of the neuroblastoma genome with transcriptional signals. Overall, our observations indicate that there exists a pan-neuroblastoma cancer cell state which may be an attractive target for novel therapeutic avenues.

cancer biology↗

bioRxiv2020

Cellular mRNA signals in human kidney tumors

The cellular transcriptome may provide clues into the differentiation state and origin of human cancer, as tumor cells may retain patterns of gene expression similar to the cell they derive from. Here, we studied the differentiation state and cellular origin of human kidney tumors, by assessing mRNA signals in 1,300 childhood and adult renal tumors, spanning seven different tumor types. Using single cell mRNA reference maps of normal tissues generated by the Human Cell Atlas project, we measured the abundance of reference "cellular signals" in each tumor. Quantifying global differentiation states, we found that, irrespective of tumor type, childhood tumors exhibited fetal cellular signals, thus replacing the long-held presumption of "fetalness" with a precise, quantitative readout of immaturity. By contrast, in adult cancers our assessment refuted the suggestion of dedifferentiation towards a fetal state in the overwhelming majority of cases, with the exception of lethal variants of clear cell renal cell carcinoma. Examining the specific cellular phenotype of each tumor type revealed an intimate connection between the different mesenchymal populations of the developing kidney and childhood renal tumors, whereas adult tumors mostly represented specific mature tubular cell types. RNA signals of each tumor type were remarkably uniform and specific, indicating a possible therapeutic and diagnostic utility. We demonstrated this utility with a case study of a cryptic renal tumor. Whilst not classifiable by clinical pathological work-up, mRNA signals revealed the diagnosis. Our findings provide a cellular definition of human renal tumors through an approach that is broadly applicable to human cancer.

cancer biology↗