| 摘要(英) |
Tumors contain a small subpopulation of cancer-initiating cells, known as cancer stem cells (CSCs), which exhibit a self-renewing capacity and are responsible for tumor generation. CSCs are reputed not to be typical cancer cells, and they may persist in tumors as a distinct population, causing relapse and metastasis by giving rise to new tumors. The first evidence for CSCs was reported in 1997 in a study that an isolated subpopulation of leukemic cells that expressed a specific surface marker, CD34, but lacked the CD38 marker; established that the CD34+/CD38- subpopulation was capable of initiating tumors in non-obese diabetic/severe combined immunodeficiency (SCID) mice and that these tumors were histologically similar to the primary leukemic tumors.
CSCs can form tumors and it has been suggested that CSCs persist in tumors as a distinct population and cause relapse and metastasis by giving rise to new tumors. The hypothesis that stem cells drive tumorigenesis in colon cancer raises the question of whether current anticancer therapies can efficiently target the tumorigenic cell population that is responsible for tumor growth and metastasis since current therapies mostly fail to eradicate CSC clones and instead favor expansion of the CSC pool and/or select for drug-resistant CSC clones. The isolation and characterization of tumorigenic colon CSCs should enable the development of novel diagnostic and therapeutic procedures.
Specific surface markers for colon CSCs have been reported, and CD133 is the most studied surface marker for colon CSCs. Using CD133 to identify and confirm expansion of human colon CSCs has been reported. CD133+ colon cancer cells injected subcutaneously readily generated a tumor in SCID mice, whereas CD133- cells did not form tumors but with controversial results.
Using a knock-in lacZ reporter mouse (CD133lacz/+) in which the expression of lacZ was driven by the endogenous CD133 promoters, CD133 expression in the colon was found not to be restricted to stem cells alone; CD133 was ubiquitously expressed on differentiated colonic epithelia. An examination of CD133 expression did not reveal the entire population of CSCs in human metastatic colon cancer; both CD133+ and CD133- metastatic tumor subpopulations were capable of long-term tumorigenesis in a non-obese diabetic/SCID xenotransplantation model.
Other colon CSC markers have been proposed including epithelial specific antigen (EpCAM, BerEp4; cell adhesion molecule), CD44 (CDW44; cell adhesion molecule, hyaluronic acid receptor), CD166 (ALCAM; cell adhesion molecule), Msi-1 (Musashi-1; RNA-binding protein), CD29 (integrin β1; cell adhesion molecule), CD24 (HSA; cell adhesion molecule), Lgr5 (GPR49; Wnt targeting gene), and ALDH-1 (ALDC; enzyme). Exact and reliable surface markers of colon CSCs, however, have not yet been identified. Presently, the only reliable method for identifying and quantifying CSCs is to observe tumor formation in a serial xenotransplantation model.
It is generally accepted that CSCs express active transmembrane ATP-binding cassette (ABC) transporter family members, such as the multidrug-resistant transporter 1 and ABC sub-family G member 2 (ABCG2),7 which render them drug resistant. Drug-resistant cells from human colorectal adenocarcinoma tumors produced two orders higher than normal levels of carcinoembryonic antigen (CEA) per cell. Only 1% of cells treated with acetylsalicylic acid (aspirin) in their culture medium survived, compared with cells grown in the normal expansion medium. This raised questions about whether the drug-resistant colorectal cells, which are increased by adding anticancer drugs into the culture medium, might be CSCs; if so, this method might be the simplest isolation method for CSCs. It will also be important to determine which anticancer drugs or chemotherapy treatments can efficiently deplete CSCs when colon cancer cells are subcutaneously xenotransplanted into mice after the cells have been treated with anticancer drugs.
In this paper, the higher levels of CEA secreted by the LoVo colon carcinoma cell line, which was cultured in serum-free and serum-containing media containing anticancer drugs will be evaluated. Drug-resistant LoVo cells were analyzed to determine whether those cells had CSC characteristics, e.g., small size of the cells/colonosphere and strong expression of CSC surface markers, as indicated by flow cytometry and immunohistochemistry analysis. Finally, in vivo tumorigenesis was examined by subcutaneously xenotrans- planting the isolated drug-resistant LoVo cells into mice. Drug-resistant cells isolated in this study were CSCs will be evaluated.
In conclusion the production of CEA by LoVo cells can be stimulated by the addition of anticancer drugs as well as aspirin in both serum-free and serum-containing media. CSCs are believed to be drug resistant cells; however, although the drug-resistant subpopulation of LoVo colon cancer cells, which were isolated by the addition of anticancer drugs to the culture medium, could stimulate the production of CEA in both serum-free and serum-containing media, these cells did not act as CSCs in in vivo tumor generation experiments. In the clinic, a CEA surge or flare has been observed as an early biochemical phenomenon in metastatic colorectal cancer during chemotherapy in approximately 10% of the patients who experience a clinical benefit. In light of this clinical evidence, we speculate that drug-resistant can?cer cells are not CSCs because patients with CEA surges experience a clinical benefit, which is inconsistent with the CSC theory that predicts that these patients would have a worse prognosis.
|
| 參考文獻 |
1. Trumpp A, Wiestler OD. Mechanisms of disease: cancer stem cells –
targeting the evil twin. Nat Clin Pract Oncol. 2008;5(6):337–347.
2. Bonnet D, Dick JE. Human acute myeloid leukemia is organized as a
hierarchy that originates from a primitive hematopoietic cell. Nat Med.
1997;3(7):730–737.
3. Ferlay J, Autier P, Boniol M, Heanue M, Colombet M, Boyle P. Estimates
of the cancer incidence and mortality in Europe in 2006. Ann Oncol.
2007;18(3):581–592.
4. Ricci-Vitiani L, Fabrizi E, Palio E, De Maria R. Colon cancer stem
cells. J Mol Med (Berl). 2009;87(11):1097–1104.
5. Todaro M, Francipane MG, Medema JP, Stassi G. Colon cancer stem
cells: promise of targeted therapy. Gastroenterology. 2010;138(6):
2151–2162.
6. Papailiou J, Bramis KJ, Gazouli M, Theodoropoulos G. Stem cells in
colon cancer. A new era in cancer theory begins. Int J Colorectal Dis.
2011;26(1):1–11.
7. Klonisch T, Wiechec E, Hombach-Klonisch S, et al. Cancer stem cell
markers in common cancers – therapeutic implications. Trends Mol
Med. 2008;14(10):450–460.
8. Ricci-Vitiani L, Lombardi DG, Pilozzi E, et al. Identification and
expansion of human colon-cancer-initiating cells. Nature. 2007;
445(7123):111–115.
9. Vermeulen L, Todaro M, de Sousa Mello F, et al. Single-cell cloning of
colon cancer stem cells reveals a multi-lineage differentiation capacity.
Proc Natl Acad Sci U S A. 2008;105(36):13427–13432.
10. O’Brien CA, Pollett A, Gallinger S, Dick JE. A human colon cancer cell
capable of initiating tumour growth in immunodeficient mice. Nature.
2007;445(7123):106–110.
11. Ferrand A, Sandrin MS, Shulkes A, Baldwin GS. Expression of gastrin
precursors by CD133-positive colorectal cancer cells is crucial for
tumour growth. Biochim Biophys Acta. 2009;1793(3):477–488.
12. Singh SK, Hawkins C, Clarke ID, et al. Identification of human brain
tumour initiating cells. Nature. 2004;432(7015):396–401.
13. Hilbe W, Dirnhofer S, Oberwasserlechner F, et al. CD133 positive
endothelial progenitor cells contribute to the tumour vasculature in
non-small cell lung cancer. J Clin Pathol. 2004;57(9):965–969.
14. Shmelkov SV, Butler JM, Hooper AT, et al. CD133 expression is not
restricted to stem cells, and both CD133+ and CD133– metastatic colon
cancer cells initiate tumors. J Clin Invest. 2008;118(6):2111–2120.
15. Lugli A, Iezzi G, Hostettler I, et al. Prognostic impact of the expression
of putative cancer stem cell markers CD133, CD166, CD44 s, EpCAM,
and ALDH1 in colorectal cancer. Br J Cancer. 2010;103(3):382–390.
16. Horst D, Kriegl L, Engel J, Kirchner T, Jung A. CD133 expression is
an independent prognostic marker for low survival in colorectal cancer.
Br J Cancer. 2008;99(8):1285–1289.
17. Du L, Rao G, Wang H, et al. CD44-positive cancer stem cells expressing
cellular prion protein contribute to metastatic capacity in colorectal
cancer. Cancer Res. 2013;73(8):2682–2694.
18. Li CY, Li BX, Liang Y, et al. Higher percentage of CD133+ cells is
associated with poor prognosis in colon carcinoma patients with stage
IIIB. J Transl Med. 2009;7:56–63.
19. Crea F, Fornaro L, Masi G, Falcone A, Danesi R, Farrar W. Faithful
markers of circulating cancer stem cells: is CD133 sufficient for validation
in clinics? J Clin Oncol. 2011;29(25):3487–3488.
20. Chu P, Clanton DJ, Snipas TS, et al. Characterization of a subpopulation
of colon cancer cells with stem cell-like properties. Int J Cancer.
2009;124(6):1312–1321.
21. LaBarge MA, Bissell MJ. Is CD133 a marker of metastatic colon cancer
stem cells? J Clin Invest. 2008;118(6):2021–2024.
22. Du L, Wang H, He L, et al. CD44 is of functional importance for colorectal
cancer stem cells. Clin Cancer Res. 2008;14(21):6751–6760.
23. Dalerba P, Dylla SJ, Park IK, et al. Phenotypic characterization of human
colorectal cancer stem cells. Proc Natl Acad Sci U S A. 2007;104(24):
10158–10163.
24. Todaro M, Perez Alea M, Scopelliti A, Medema JP, Stassi G. IL-4-
mediated drug resistance in colon cancer stem cells. Cell Cycle.
2008;7(3):309–313.
25. Huang EH, Hynes MJ, Zhang T, et al. Aldehyde dehydrogenase 1 is a
marker for normal and malignant human colonic stem cells (SC) and
tracks SC overpopulation during colon tumorigenesis. Cancer Res.
2009;69(8):3382–3389.
26. Lohberger B, Rinner B, Stuendl N, et al. Aldehyde dehydrogenase 1, a
potential marker for cancer stem cells in human sarcoma. PLoS One.
2012;7(8):e43664.
27. Garcia VM, Batlle JF, Casado E, et al. Immunohistochemical analysis
of tumour regression grade for rectal cancer after neoadjuvant
chemoradiotherapy.
Colorectal Dis. 2011;13(9):989–998.
28. Fan LF, Dong WG, Jiang CQ, Xia D, Liao F, Yu QF. Expression of
putative stem cell genes Musashi-1 and beta1-integrin in human colorectal
adenomas and adenocarcinomas. Int J Colorectal Dis. 2010;25(1):
17–23.
29. Fan X, Ouyang N, Teng H, Yao H. Isolation and characterization of
spheroid cells from the HT29 colon cancer cell line. Int J Colorectal
Dis. 2011;26(10):1279–1285.
30. Hellsten R, Johansson M, Dahlman A, Sterner O, Bjartell A.
Galiellalactone
inhibits stem cell-like ALDH-positive prostate cancer
cells. PLoS One. 2011;6(7):e22118.
31. Singh A, Settleman J. EMT, cancer stem cells and drug resistance: an
emerging axis of evil in the war on cancer. Oncogene. 2010;29(34):
4741–4751.
32. Higuchi A, Uchiyama S, Demura M, et al. Enhanced CEA production
associated with aspirin in a culture of CW-2 cells on some polymeric
films. Cytotechnology. 1999;31(3):233–242.
33. Zhang J, Li H, Wang X, et al. Phage-derived fully human antibody
scFv fragment directed against human vascular endothelial growth
factor receptor 2 blocked its interaction with VEGF. Biotechnol Prog.
2012;28(4):981–989.
34. Alfred R, Radford J, Fan J, et al. Ef?cient suspension bioreactor expansion
of murine embryonic stem cells on microcarriers in serum-free
medium. Biotechnol Prog. 2011;27(3):811–823.
35. Higuchi A, Huang SC, Shen PY, et al. Differentiation ability of amniotic
fluid-derived stem cells cultured on extracellular matrix-immobilized
surface. Curr Nanosci. 2011;7(6):893–901.
36. Liu JY, Peng HF, Gopinath S, Tian J, Andreadis ST. Derivation of
functional smooth muscle cells from multipotent human hair follicle
mesenchymal stem cells. Tissue Eng Part A. 2010;16(8):2553–2564.
37. Shi B, Deng L, Shi X, et al. The enhancement of neural stem cell survival
and growth by coculturing with expanded sertoli cells in vitro.
Biotechnol Prog. 2012;28(1):196–205.
38. Mohr JC, de Pablo JJ, Palecek SP. Electroporation of human embryonic
stem cells: small and macromolecule loading and DNA transfection.
Biotechnol Prog. 2006;22(3):825–834.
39. Malpique R, Tostoes R, Beier AFJ, et al. Surface-based cryopreservation
strategies for human embryonic stem cells: a comparative study.
Biotechnol Prog. 2012;28(4):1079–1087.
40. Aquino A, Prete SP, Guadagni F, et al. Effect of 5-fluorouracil on carcinoembryonic
antigen expression and shedding at clonal level in colon
cancer cells. Anticancer Res. 2000;20(5B):3475–3484.
41. Prete SP, Rossi L, Correale PP, et al. Combined effects of protein kinase
inhibitors and 5-fluorouracil on CEA expression in human colon cancer
cells. Pharmacol Res. 2005;52(2):167–173.
42. Yan H, Chen X, Zhang Q, et al. Drug-tolerant cancer cells show reduced
tumor-initiating capacity: depletion of CD44 cells and evidence for
epigenetic mechanisms. PLoS One. 2011;6(9):e24397.
43. Staab HJ, Anderer FA, Brummendorf T, Stumpf E, Fischer R. Prognostic
value of preoperative serum CEA level compared to clinical staging. I.
colorectal carcinoma. Br J Cancer. 1981;44(5):652–662.
44. Wolmark N, Fisher B, Wieand HS, et al. The prognostic significance
of preoperative carcinoembryonic antigen levels in colorectal cancer.
Results from NSABP (National Surgical Adjuvant Breast and Bowel
Project) clinical trials. Ann Surg. 1984;199(4):375–382.
45. Ailawadhi S, Sunga A, Rajput A, Yang GY, Smith J, Fakih M.
Chemotherapy-
induced carcinoembryonic antigen surge in patients
with metastatic colorectal cancer. Oncology. 2006;70(1):49–53.
46. Fakih MG, Padmanabhan A. CEA monitoring in colorectal cancer. What
you should know. Oncology (Williston Park). 2006;20(6):579–587.
47. Sorbye H, Dahl O. Carcinoembryonic antigen surge in metastatic
colorectal cancer patients responding to oxaliplatin combination chemotherapy:
implications for tumor marker monitoring and guidelines.
J Clin Oncol. 2003;21(23):4466–4467. |
[Endnote RIS 格式]
[相關文章]
[文章引用]
[完整記錄]
[館藏目錄]
至系統瀏覽論文 ( 永不開放)
plurk
funp
live
udn
HD
myshare
netvibes
friend
youpush
delicious
baidu
Google bookmarks
del.icio.us
hemidemi
facebook
twitter
google
reddit