No abstract

Colorectal cancer (CRC) is one of the most common and fatal gastrointestinal cancers worldwide. Considering their diversity, the establishment of new continuous CRC cell lines with clear genetic backgrounds will provide useful tools for exploring molecular mechanisms, screening and evaluating antitumor drugs in CRC studies. Our de novo CRC cell line, PUMC-CRC1 (Peking Union Medical College Colorectal Cancer 1) was derived from a 47-year-old Chinese female patient diagnosed with moderately to poorly differentiated colon adenocarcinoma. Multiple experiments were used for full characterization. The new cell line was epithelial-like and was passaged for more than 40 times, with a population doubling time of 44 h in vitro, detected by cell counts. The cells exhibited complicated chromosomal abnormalities. The tumor formation rate in SCID mice was 100%. The xenograft tumor was adenocarcinoma with poor to moderate differentiation by Haematoxylin and Eosin staining (H&E) sections. Immunohistochemistry (IHC) analysis and next-generation sequencing (NGS) revealed microsatellite stable (MSS), APC (p.T1493fs) inactivation, KRAS (p.G12V) activation, and SMAD4 (p.V506A) mutation. Quality control of the cell line proved mycoplasma negative and identical STR profile with that of the original tissue, and no interspecific or intraspecific cross contamination was detected. In conclusion, PUMC-CRC1 was a newly established and well characterized human colon cancer cell line, which might be a good model for both in vitro and in vivo studies of the mechanism of colon cancer progression and the treatment strategies for MSS CRC.

The short‐tandem‐repeats (STR) profiles of MGc80‐3 and HeLa partially overlap, raising suspicion of contamination in the MGc80‐3 cell line. However, there has not been any relevant study demonstrating whether MGc80‐3 was fully replaced by HeLa cells, just mixed with HeLa cells (co‐existing), or was a somatic hybrid with HeLa cells. In addition to STR profiling, various approaches, including single nucleotide polymorphisms genotyping, polymerase chain reaction, screening for human papillomaviruses type 18 (HPV‐18) fragment, chromosome karyotyping, pathological examination of xenografts, tissue‐specific‐90‐gene expression signature and high‐throughput RNA sequencing were used to determine the nature of MGc80‐3. Our study found that the abnormal STR profile, partially overlapping with that of HeLa cells (64.62% to 71.64%), could not verify MGc80‐3 as a HeLa cell line. However, the STR 13.3 repeat allele in the D13S317 locus that seemed to be unique to HeLa cells was detected in MGc80‐3. Almost all the MGc80‐3 cells exhibited HPV‐18 fragments in the genome as well as certain HeLa marker chromosomes, such as M7 and M12. The molecular assay of the 90‐gene expression signature still considered MGc80‐3 as a stomach cancer using an algorithmic analysis. The expression pattern of multiple genes in MGc80‐3 was quite different from that in HeLa cells, which showed that certain characteristics belonged to gastric cancer cell lines. High throughput RNA sequencing showed the distinct patterns of gene expression in MGc80‐3. In conclusion, MGc80‐3 cell line is a somatic hybrid with HeLa cells rather than a pure gastric cancer cell line.