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CD49f(high) cells retain sphere-forming and tumor-initiating activities in human gastric tumors.

Fukamachi H, Seol HS, Shimada S, Funasaka C, Baba K, Kim JH, Park YS, Kim MJ, Kato K, Inokuchi M, Kawachi H, Yook JH, Eishi Y, Kojima K, Kim WH, Jang SJ, Yuasa Y - PLoS ONE (2013)

Bottom Line: We thus searched for another marker for gastric TICs, and found that CD49f(high) cells from newly-dissected gastric cancers formed tumors with histological features of parental ones while CD49f(low) cells did not when subcutaneously injected into immunodeficient mice.Using this system, we found that some sphere-forming TICs were more resistant than gastric tumor cell lines to chemotherapeutic agents, including doxorubicin, 5-fluorouracil and doxifluridine.There was a patient-dependent difference in the tumorigenicity of sphere-forming TICs and their response to anti-tumor drugs.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Oncology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.

ABSTRACT
Identification of gastric tumor-initiating cells (TICs) is essential to explore new therapies for gastric cancer patients. There are reports that gastric TICs can be identified using the cell surface marker CD44 and that they form floating spheres in culture, but we could not obtain consistent results with our patient-derived tumor xenograft (PDTX) cells. We thus searched for another marker for gastric TICs, and found that CD49f(high) cells from newly-dissected gastric cancers formed tumors with histological features of parental ones while CD49f(low) cells did not when subcutaneously injected into immunodeficient mice. These results indicate that CD49f, a subunit of laminin receptors, is a promising marker for human gastric TICs. We established a primary culture system for PDTX cells where only CD49f(high) cells could grow on extracellular matrix (ECM) to form ECM-attaching spheres. When injected into immunodeficient mice, these CD49f(high) sphere cells formed tumors with histological features of parental ones, indicating that only TICs could grow in the culture system. Using this system, we found that some sphere-forming TICs were more resistant than gastric tumor cell lines to chemotherapeutic agents, including doxorubicin, 5-fluorouracil and doxifluridine. There was a patient-dependent difference in the tumorigenicity of sphere-forming TICs and their response to anti-tumor drugs. These results suggest that ECM plays an essential role for the growth of TICs, and that this culture system will be useful to find new drugs targeting gastric TICs.

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Sphere cells form tumors with histological features of parental ones.Light micrographs of tumors formed by subcutaneous injection of sphere cells into NOD-SCID mice (right panels), which are obtained by cultures of (A) unsorted HGC-1, (B) unsorted HGC-2 and (C) unsorted HGC-4 tumor cells. Histological features of tumors formed in mice correspond well with those of parental ones (left panels). Tissue specimens are stained with hematoxylin and eosin. Scale bars represent 50 µm.
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pone-0072438-g004: Sphere cells form tumors with histological features of parental ones.Light micrographs of tumors formed by subcutaneous injection of sphere cells into NOD-SCID mice (right panels), which are obtained by cultures of (A) unsorted HGC-1, (B) unsorted HGC-2 and (C) unsorted HGC-4 tumor cells. Histological features of tumors formed in mice correspond well with those of parental ones (left panels). Tissue specimens are stained with hematoxylin and eosin. Scale bars represent 50 µm.

Mentions: We then examined tumorigenicity of these sphere-forming CD49fhigh cells. We found that sphere cells obtained by primary culture of unsorted HGC-1 tumor cells were strongly tumorigenic because subcutaneously injection of 3,000 sphere cells always formed tumors and injection of 10 cells sometimes formed a tumor in NOD-SCID mice (Table 2). The tumors exhibited histological features of the parental one (Figure 4), indicating that the CD49fhigh sphere-forming cells retained differentiation potency of TICs in the original tumor. Sphere cells obtained by culture of unsorted HGC-2 and HGC-4 cells also formed tumors with histological features of parental ones (Table 2 and Figure 4), but tumorigenicity of HGC-4 sphere cells was less than that of HGC-1 sphere cells, and that of HGC-2 sphere cells was at the intermediate between HGC-1 and HGC-4 sphere cells (Table 2). We thus concluded that only CD49fhigh sphere-forming TICs could grow when unsorted tumor cells were cultured. These results are consistent with our idea that CD49f is a useful marker for gastric TICs.


CD49f(high) cells retain sphere-forming and tumor-initiating activities in human gastric tumors.

Fukamachi H, Seol HS, Shimada S, Funasaka C, Baba K, Kim JH, Park YS, Kim MJ, Kato K, Inokuchi M, Kawachi H, Yook JH, Eishi Y, Kojima K, Kim WH, Jang SJ, Yuasa Y - PLoS ONE (2013)

Sphere cells form tumors with histological features of parental ones.Light micrographs of tumors formed by subcutaneous injection of sphere cells into NOD-SCID mice (right panels), which are obtained by cultures of (A) unsorted HGC-1, (B) unsorted HGC-2 and (C) unsorted HGC-4 tumor cells. Histological features of tumors formed in mice correspond well with those of parental ones (left panels). Tissue specimens are stained with hematoxylin and eosin. Scale bars represent 50 µm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3756075&req=5

pone-0072438-g004: Sphere cells form tumors with histological features of parental ones.Light micrographs of tumors formed by subcutaneous injection of sphere cells into NOD-SCID mice (right panels), which are obtained by cultures of (A) unsorted HGC-1, (B) unsorted HGC-2 and (C) unsorted HGC-4 tumor cells. Histological features of tumors formed in mice correspond well with those of parental ones (left panels). Tissue specimens are stained with hematoxylin and eosin. Scale bars represent 50 µm.
Mentions: We then examined tumorigenicity of these sphere-forming CD49fhigh cells. We found that sphere cells obtained by primary culture of unsorted HGC-1 tumor cells were strongly tumorigenic because subcutaneously injection of 3,000 sphere cells always formed tumors and injection of 10 cells sometimes formed a tumor in NOD-SCID mice (Table 2). The tumors exhibited histological features of the parental one (Figure 4), indicating that the CD49fhigh sphere-forming cells retained differentiation potency of TICs in the original tumor. Sphere cells obtained by culture of unsorted HGC-2 and HGC-4 cells also formed tumors with histological features of parental ones (Table 2 and Figure 4), but tumorigenicity of HGC-4 sphere cells was less than that of HGC-1 sphere cells, and that of HGC-2 sphere cells was at the intermediate between HGC-1 and HGC-4 sphere cells (Table 2). We thus concluded that only CD49fhigh sphere-forming TICs could grow when unsorted tumor cells were cultured. These results are consistent with our idea that CD49f is a useful marker for gastric TICs.

Bottom Line: We thus searched for another marker for gastric TICs, and found that CD49f(high) cells from newly-dissected gastric cancers formed tumors with histological features of parental ones while CD49f(low) cells did not when subcutaneously injected into immunodeficient mice.Using this system, we found that some sphere-forming TICs were more resistant than gastric tumor cell lines to chemotherapeutic agents, including doxorubicin, 5-fluorouracil and doxifluridine.There was a patient-dependent difference in the tumorigenicity of sphere-forming TICs and their response to anti-tumor drugs.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Oncology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.

ABSTRACT
Identification of gastric tumor-initiating cells (TICs) is essential to explore new therapies for gastric cancer patients. There are reports that gastric TICs can be identified using the cell surface marker CD44 and that they form floating spheres in culture, but we could not obtain consistent results with our patient-derived tumor xenograft (PDTX) cells. We thus searched for another marker for gastric TICs, and found that CD49f(high) cells from newly-dissected gastric cancers formed tumors with histological features of parental ones while CD49f(low) cells did not when subcutaneously injected into immunodeficient mice. These results indicate that CD49f, a subunit of laminin receptors, is a promising marker for human gastric TICs. We established a primary culture system for PDTX cells where only CD49f(high) cells could grow on extracellular matrix (ECM) to form ECM-attaching spheres. When injected into immunodeficient mice, these CD49f(high) sphere cells formed tumors with histological features of parental ones, indicating that only TICs could grow in the culture system. Using this system, we found that some sphere-forming TICs were more resistant than gastric tumor cell lines to chemotherapeutic agents, including doxorubicin, 5-fluorouracil and doxifluridine. There was a patient-dependent difference in the tumorigenicity of sphere-forming TICs and their response to anti-tumor drugs. These results suggest that ECM plays an essential role for the growth of TICs, and that this culture system will be useful to find new drugs targeting gastric TICs.

Show MeSH
Related in: MedlinePlus