Characterisation of four merkel cell carcinoma adherent cell lines

Abstract

We have previously described the establishment of a number of cell lines from Merkel cell carcinoma (MCC), also known as small cell cancer of the skin or neuroendocrine carcinoma of the skin. These cells, all of which grew as suspension cultures, were found to resemble small cell lung cancer (SCLC) lines types 1, 2 and 3 by their morphology and growth characteristics. We now report 4 more MCC cell lines which resemble the SCLC type 4 cell lines in that they grow as adherent monolayers. These MCC lines would belong to the variant subgroup as they no longer express most neuroendocrine markers, grow at low cell density and have population doubling times of 1-5 days in contrast to the MCC suspension lines which have doubling times of 6-12 days. MCC14/1 and MCC14/2 were established from the same metastatic node and would appear to represent 2 clones of the tumour which differ in morphology, histochemical markers and DNA content. We present details of the morphology, DNA content and immunohistochemistry of these 4 lines and compare their growth patterns with those of SCLC and MCC lines which grow in suspension.

T antigen mutations are a human tumor-specific signature for Merkel cell polyomavirus

“…These cell culture characteristics reflect differences in gene expression profiles, suggesting that MCC may have multiple different causes (19). We tested one classic (MKL-1) (20, 21) and three variant (UISO, MCC13, MCC26) cell lines (21)(22)(23), and several common laboratory cell lines, for the presence of MCV infection [supporting information (SI) Table S1]. Only the classic cell line MKL-1 harbors MCV infection.…”

Gene-expression profiling reveals distinct expression patterns for Classic versus Variant Merkel cell phenotypes and new classifier genes to distinguish Merkel cell from small-cell lung carcinoma

“…Due to the small gene-expression level variances between MCC and SCLC, as a result of their similarity, we had to choose a rather low delta (D ¼ 0.33878) in order to include as many genes as possible with significant but sometimes small expression differences in MCC versus SCLC and Classic MCC cell lines express neuroendocrine markers including neuron-specific enolase and Chromogranin A, and contain neurosecretory granules (Leonard et al, 1993). Variant MCC cell lines have a selective loss of neuroendocrine markers including Chromogranin A, and do not contain neurosecretory granules, as evidenced by electron microscopy (Leonard et al, 1995a vice versa. This led to the identification of a total of 121 differentially expressed genes with a median FDR of 27.9%, that is, 33.8 false-positive genes on average.…”

“…be made. Originally, the grouping of Classic and Variant phenotypes for MCCs was cell line based (Leonard et al, 1993;Leonard et al, 1995aLeonard et al, , 2002Leonard and Bell, 1997). However, we have observed concordant results between tumor samples and their respective cell lines in several genomic deletion analyses (Leonard and Hayard, 1997;Leonard et al, 2000;Van Gele et al, 2000;Cook et al, 2001) and in immunohistochemical studies.…”

“…Merkel cell carcinoma cell lines MCC5, MCC6, MCC13, MCC14/1, MCC14/2 and MCC26 were established at the Queensland Radium Institute Research Unit, Queensland, Australia and have been described in detail previously by Leonard et al (1993Leonard et al ( , 1995a. MCC cell line UISO was described by Ronan et al (1993) and MKL-1 by Rosen et al (1987).…”

“…Further support for this hypothesis comes from the fact that cell lines derived from MCC and SCLC resemble each other in their biochemical, morphological and growth characteristics. Similar to SCLC, MCC cell lines are classified into two groups: 'Classic' and 'Variant' defined on their biochemical markers and neurosecretory granule status, which are further subdivided into four subtypes (I-IV) based on morphology, colony shape and aggregation Gazdar et al, 1985;Leonard et al, 1993Leonard et al, , 1995aLeonard et al, , 2002Leonard and Bell, 1997). At present, little is known about the genes associated with these characteristics.…”