Association between tumorigenic potential and the fate of cancer cells in a syngeneic melanoma model

PLoS One. 2013 Apr 23;8(4):e62124. doi: 10.1371/journal.pone.0062124. Print 2013.

Abstract

The self-renewal potential of a cancer cell can be estimated by using particular assays, which include xenotransplantation in immunocompromised animals or culturing in non-adherent serum-free stem-cells media (SCM). However, whether cells with self-renewal potential actually contribute to disease is unknown. Here we investigated the tumorigenic potential and fate of cancer cells in an in-vivo melanoma model. We examined cell lines which were derived from the same parental line: a non-metastatic cell line (K1735/16), a metastatic cell line (K1735/M4) and a cell line which was selected in non-adherent conditions (K1735/16S). All cell lines exhibited similar proliferation kinetics when grown on culture plates. K1735/16 cells grown in soft agar or in suspension non-adherent conditions failed to form colonies or spheroids, whereas the other cell lines showed prominent colonogenicity and spheroid formation capacity. By using sphere limiting dilution analysis (SLDA) in serum-free media, K1735/16S and K1735/M4 cells grown in suspension were capable of forming spheroids even in low frequencies of concentrations, as opposed to K1735/16 cells. The tumorigenic potential of the cell lines was determined in SCID mice using intra footpad injections. Palpable tumors were evident in all mice. In agreement with the in-vitro studies, the K1735/M4 cell line exhibited the highest growth kinetics, followed by the K1735/16S cell line, whereas the K1735/16 cell line had the lowest tumor growth potential (P<0.001). In contrast, when we repeated the experiments in syngeneic C3H/HeN mice, the K1735/16 cell line produced macroscopic tumors 30-100 days after injection, whereas K1735/M4 and K1735/16S derived tumors regressed spontaneously in 90-100% of mice. TUNEL analysis revealed significantly higher number of apoptotic cells in K1735/16S and K1735/M4 cell line-derived tumors compared to K1735/16 tumors (P<0.001). The models we have examined here raised the possibility, that cells with high-tumorigenic activity may be more immunogenic and hence are more susceptible to immune-regulation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Apoptosis
  • Biomarkers / metabolism
  • Cell Line, Tumor
  • Disease Models, Animal
  • Female
  • Gene Expression
  • Immunophenotyping
  • Melanoma / genetics
  • Melanoma / metabolism*
  • Mice
  • Mice, SCID
  • Neoplasm Regression, Spontaneous
  • Neoplasm Transplantation
  • Neoplastic Stem Cells / metabolism*
  • Spheroids, Cellular
  • Transplantation, Isogeneic
  • Tumor Cells, Cultured
  • Tumor Stem Cell Assay

Substances

  • Biomarkers

Grants and funding

This research was supported by the Israel Science Foundation (number 1680/08 and 482/11), the Israel Cancer Association (grant donated by Ellen and Emanuel Kronitz in memory of Dr Leon Kronitz number 20090068), the Israeli Ministry of Health (number 3-7355), the Weizmann Institute - Sourasky Medical Center Joint Grant, the Tel Aviv Sourasky Intramural Grant, the ICRF Barbara S. Goodman endowed research career development award (2011-601-BGPC) and a grant from the US-Israel Binational Science Foundation (number 2007312) to Z.G. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.