CD133 expression in rectal cancer after preoperative chemoradiotherapy

CD133-positive cells have been reported to possess a cancer-initiating-cell phenotype and the property of resistance to chemoradiation therapy in colorectal cancer. The aim of the present study was to evaluate quantitative and locational changes in CD133-positive cells in rectal cancer patients who received preoperative chemoradiation therapy. The prognostic significance of CD133 expression in patients with preoperative chemoradiation therapy was also analyzed. Immunohistochemical staining for CD133 and cancer-initiating-cell marker CD44 were performed in 92 surgically resected rectal cancers. Of the 92 cases, 43 patients received preoperative chemoradiation therapy and 49 patients underwent surgery alone. Forty pretherapic biopsy specimens from 43 patients in preoperative chemoradiation therapy group were also analyzed. CD133-positive cases were more common in the preoperative chemoradiation therapy group than in the surgery-alone group (P = 0.03). Further, CD133-positive cases were more common in the preoperative chemoradiation therapy group than in pretherapic biopsy specimens (P = 0.02). In the preoperative chemoradiation therapy group, the CD133-positive cases showed poorer prognosis than the CD133-negative cases. On the other hand, the frequency of CD44-positive case within cancer tissue was similar between the preoperative chemoradiation therapy group and the surgery-alone group. CD44 expression in the preoperative chemoradiation therapy group was not associated with prognosis. CD44- and CD133-positive cells were distributed evenly within the tumor both in the preoperative chemoradiation therapy group and surgery-alone group, and locational alteration was not observed. The therapy-resistant ability of CD133-positive cells can be associated with poor outcome in the patients with preoperative chemoradiation therapy.

Demethylation of the CD133 gene is frequently detected in early gastric carcinoma

BACKGROUND

Recently, it has been reported that colorectal carcinoma is created and propagated by a small number of undifferentiated tumorigenic CD133(+) cells. Furthermore, it has been reported that CD133 expression is directly regulated by epigenetic modifications. Therefore, it is possible that CD133 expression by gene demethylation is related to colorectal and gastric carcinogenesis.

MATERIALS AND METHODS

The methylation status of the CD133 gene was examined in primary carcinomas and the corresponding normal tissues derived from 36 patients with gastric cancer using quantitative methylation-specific polymerase chain reaction (qMSP) and the correlation between the methylation status and the clinicopathological findings was evaluated.

RESULTS

Demethylation of the CD133 gene was detected in 14 out of the 36 (39%) primary gastric carcinomas, suggesting that the demethylation of CD133 is frequently observed in gastric carcinomas. The clinicopathological data were correlated with the demethylation results. A significant decrease of CD133 methylation was observed in the extent of tumor (p=0.0421). Moreover, a trend was shown toward smaller maximal tumor size in tumors with demethylated CD133 (p=0.0556).

CONCLUSION

CD133 appears to be frequently demethylated in early gastric carcinomas.

Co-expression of CD173 (H2) and CD174 (Lewis Y) with CD44 suggests that fucosylated histo-blood group antigens are markers of breast cancer-initiating cells

Histo-blood group antigens CD173 (H2) and CD174 (Lewis Y) are known to be developmentally regulated carbohydrate antigens which are expressed to a varying degree on many human carcinomas. We hypothesized that they might represent markers of cancer-initiating cells (or cancer stem cells, CSC). In order to test this hypothesis, we examined the co-expression of CD173 and CD174 with stem cell markers CD44 and CD133 by flow cytometry analysis, immunocytochemistry, and immunohistochemistry on cell lines and tissue sections from breast cancer. In three breast cancer cell lines, the percentage of CD173(+)/CD44(+) cells ranged from 17% to >60% and of CD174(+)/CD44(+) from 21% to 57%. In breast cancer tissue sections from 15 patients, up to 50% of tumor cells simultaneously expressed CD173, CD174, and CD44 antigens. Co-expression of CD173 and CD174 with CD133 was also observed, but to a lesser percentage. Co-immunoprecipitation and sandwich ELISA experiments on breast cancer cell lines suggested that CD173 and CD174 are carried on the CD44 molecule. The results show that in these tissues CD173 (H2) and CD174 (LeY) are associated with CD44 expression, suggesting that these carbohydrate antigens are markers of cancer-initiating cells or of early progenitors of breast carcinomas.

CD133+CD34+ stem cells are mobilized after musculoskeletal surgery and target endothelium activated by surgical wound fluid

PURPOSE

CD133+CD34+ hematopoietic stem cells (HSCs) have been shown to differentiate into cell types of nonhematopoietic lineage. It is unclear whether HSCs target and repair damaged musculoskeletal tissue. We aimed to analyze if HSCs are mobilized after musculoskeletal surgery to circulation, home to surgical wound fluid (SWF)-activated endothelium, and are chemoattracted by SWF under in vitro conditions.

METHODS

Circulating HSC levels were measured at t = 3, 8, 24, 48 h postoperatively using fluorescence-activated cell sorting (FACS) and compared with preoperative levels (t = 0) and normal volunteers. For adhesion experiments, HSCs were incubated on SWF-activated human umbilical vein endothelial cells (HUVECs) and HSC/HUVEC ratios determined by FACS. Adhesion receptor expression on HSC (L-selectin, lymphocyte function-associated antigen 1 (LFA-1), very late antigen-4) and SWF-activated HUVECs (P-selectin, E-selectin, V-cell adhesion molecules (CAM), I-CAM) was determined and HSC adhesion measured again after blocking upregulated receptors. Using a modified Boyden chamber, HSC chemotaxis was analyzed for an SWF and cytokine-neutralized SWF (vascular endothelial growth factor (VEGF), stromal-derived factor-1, interleukin-8) gradient.

RESULTS

Circulating HSCs were significantly increased 8 h after surgery. Increasing HSC adhesion to HUVECs was shown for SWF isolated at any postoperative time point, and chemoattraction was significantly induced in an SWF gradient with SWF isolated 8 and 24 h postoperatively. Receptor and cytokine blockade experiments with monoclonal antibodies revealed decreased HSC adhesion to SWF-activated endothelium and showed lower chemotaxis after blocking the LFA-1-I-CAM-1 receptor axis (adhesion) and neutralizing VEGF-165 (chemotaxis).

CONCLUSIONS

Our data demonstrate that HSCs are mobilized after trauma, target to wound-associated endothelium via the LFA-1-I-CAM-1 axis, and are chemoattracted by VEGF-165 under in vitro conditions.

Stem cell therapy for the broken heart: mini-organ transplantation

BACKGROUND

Myocardial infarction (MI) is characterized by irreversible loss of cardiomyocytes, resulting in impaired ventricular function. Stem cell therapy using autologous progenitor cells has emerged as a promising approach. Experimental studies have demonstrated that highly selected hematopoeitic stem cells, which are characterized by the presence of the surface markers CD34 and CD133, may contribute to repair of the acutely infarcted myocardium by inducing neovascularization, inhibiting apoptosis, and promoting cardiomyogenesis. We sought, to evaluate the intracoronary injection of CD133+ stem cells for cardiac repair in patients with dysfunctional myocardium after an acute MI.

PATIENTS AND METHODS

In this Canadian randomized, double-blind, placebo-controlled, Phase I-II study ("COMPARE-AMI"), we are evaluating the feasibility, safety, and efficacy of intracoronary injection of selected CD133+ stem cells for cardiac repair in patients with impaired cardiac function after successfully stented acute MI. Since November 2007, we have enrolled 14 patients in the study. Their mean age was 50.5 +/- 9.1 years, including 93% men. The culprit lesion was always on the left anterior descending artery (LAD). Their maximum troponin and CKMB levels were 8.4 +/- 6.1 microg/L and 322 +/- 225 U/L, respectively.

RESULTS

Compared with the baseline, we observed a significant 8.7% improvement in left ventricular ejection fraction at 4 months follow-up, namely, from 41.3 +/- 5.5% to 50.0 +/- 8.2% (n = 7; P = .008). There were no protocol-related complications. Our trial is designed to recruit 40 patients who are randomized 1:1 to receive CD133+ cells or placebo.

PERSPECTIVE

There is a need to seek out new therapeutics for the treatment of ischemic heart disease addressing the early loss of viable myocytes. Stem cell transplantation has shown early promise; this appraisal needs well-designed, controlled studies.

CD133 expression is not selective for tumor-initiating or radioresistant cell populations in the CRC cell line HCT-116

BACKGROUND AND PURPOSE

CD133 is controversially discussed as putative (surrogate) marker for cancer stem/tumor-initiating cell populations (CSC/TIC) in epithelial tumors including colorectal carcinomas (CRCs). We studied CD133 expression in established CRC cell lines and examined in vitro behavior, radioresponse and in vivo tumor formation of CD133+/- subpopulations of one cell line of interest.

MATERIALS AND METHODS

Ten CRC cell lines were analyzed for CD133 expression using flow cytometry and Western blotting. CD133+ and CD133- HCT-116 subpopulations were separated by FACS and studied in 2-D and 3-D culture and colony formation assays after irradiation. Subcutaneous xenograft formation was monitored in NMRI (nu/nu) mice.

RESULTS AND CONCLUSIONS

CRC cell lines could be classified into three groups: (i) CD133-, (ii) CD133+ and (iii) those with two distinct CD133+ and CD133- subpopulations. Isolated CD133+/- HCT-116 subpopulations were studied relative to the original fraction. No difference was found in 2-D growth, spheroid formation or radioresponse in vitro. Also, tumor formation and growth rate did not differ for the sorted subpopulations. However, a subset of xenografts originated from CD133- HCT-116 showed a striking enrichment in the CD133+ fraction. Our data show that CD133 expression is not selective for sphere forming, tumor-initiating or radioresistant subpopulations in the HCT-116 CRC cell line. This implies that CD133 cannot be regarded as a CSC/TIC marker in all CRC cell lines and that functional measurements of tumor formation have to generally accompany CSC/TIC-directed mechanistic or therapeutic studies.

Isolation and characterization of hepatic cancer cells with stem-like properties from hepatocellular carcinoma

BACKGROUND & AIMS

Major burdens in the treatment of hepatocellular carcinoma (HCC) are the high percentage of recurrence and resistance to chemotherapy. Hepatic cancer stem cells provide a reservoir of cells that can self-renew, maintain the tumor by generating differentiated non-stem cells which make up the bulk of the tumor and are responsible for recurrence after ablative surgery and chemoradiotherapy. The objective of this study was to identify and characterize a self-renewing subpopulation of human liver tumor cells with a distinctive genetic profile that adds the capacity to proliferate despite chemotherapy and promotes cancer recurrence.

METHODS

Stemness properties of tumor cells isolated from a HCC biopsy were established by their capacity to form spheroids and by cell proliferation assays. The cells also showed enhanced chemoresistance to cancer drugs. The up-regulation of stem cell markers is proven by immunocytochemistry stainings and reverse transcription-PCR.

RESULTS

Cells had a high proliferative potential, even when cultured in medium supplemented with doxorubicin and carboplatin, eliminated Rhodamine 123 immediately in culture and also formed spheroids in suspension. Molecular diagnosis techniques showed that cells expressed the stem cell markers Oct 3/4 and CXCR4. Cells were also positive for CD133 and CD90 cancer stem cell specific markers, with monoclonal antibody staining.

CONCLUSION

The unique characteristics identified in cancer stem cells explain self-renewal and could drive metastasis in patients that have received treatment for cancer. The identification and cloning of such cells can aid in developing of better therapeutic approaches for patients with HCC, as chemosensitive pretherapeutic assays or targeted therapies.

Human cord blood-derived AC133+ progenitor cells preserve endothelial progenitor characteristics after long term in vitro expansion

Background

Stem cells/progenitors are central to the development of cell therapy approaches for vascular ischemic diseases. The crucial step in rescuing tissues from ischemia is improvement of vascularization that can be achieved by promoting neovascularization. Endothelial progenitor cells (EPCs) are the best candidates for developing such an approach due to their ability to self-renew, circulate and differentiate into mature endothelial cells (ECs). Studies showed that intravenously administered progenitors isolated from bone marrow, peripheral or cord blood home to ischemic sites. However, the successful clinical application of such transplantation therapy is limited by low quantities of EPCs that can be generated from patients. Hence, the ability to amplify the numbers of autologous EPCs by long term in vitro expansion while preserving their angiogenic potential is critically important for developing EPC based therapies. Therefore, the objective of this study was to evaluate the capacity of cord blood (CB)-derived AC133+ cells to differentiate, in vitro, towards functional, mature endothelial cells (ECs) after long term in vitro expansion.

Methodology

We systematically characterized the properties of CB AC133+ cells over the 30 days of in vitro expansion. During 30 days of culturing, CB AC133+ cells exhibited significant growth potential that was manifested as 148-fold increase in cell numbers. Flow cytometry and immunocytochemistry demonstrated that CB AC133+ cells' expression of endothelial progenitor markers was not affected by long term in vitro culturing. After culturing under EC differentiation conditions, cells exhibited high expression of mature ECs markers, such as CD31, VEGFR-2 and von Willebrand factor, as well as the morphological changes indicative of differentiation towards mature ECs. In addition, throughout the 30 day culture cells preserved their functional capacity that was demonstrated by high uptake of DiI fluorescently conjugated-acetylated-low density lipoprotein (DiI-Ac-LDL), in vitro and in vivo migration towards chemotactic stimuli and in vitro tube formation.

Conclusions

These studies demonstrate that primary CB AC133+ culture contained mainly EPCs and that long term in vitro conditions facilitated the maintenance of these cells in the state of commitment towards endothelial lineage.

Porcine EPCs downregulate stem cell markers and upregulate endothelial maturation markers during in vitro cultivation

In recent years, interest in endothelial progenitor cells (EPCs) in the field of tissue engineering and regenerative medicine has increased tremendously. However, each clinical stem cell application requires prior validation through animal experiments. This study investigates the isolation and characterization of porcine EPCs from peripheral blood and the change of their cell surface marker expression during in vitro cultivation. RT-PCR demonstrated that the EPCs express stem cell markers CD34 and CD133, which decrease with in vitro cultivation time. Throughout the cultivation process EPCs did not express monocytic (CD14) or haematopoietic marker (CD45). Surprisingly, the CD31 and VE-cadherin expression in EPCs was significantly higher than in endothelial cells (ECs). In contrast, the VEGFR2 and E-selectin expression was significantly lower than in ECs, but increased during the expansion process. This study clarifies the characteristic properties of porcine EPCs during cell culture and may help to improve the impact of EPC-based therapies in porcine animal studies.

[Correlative study of distribution of brain tumor stem cell with micro-vascular system]

OBJECTIVE

To investigate the expressions of putative brain tumor stem cell (BTSC) marker CD133, Nestin and blood vessel endothelial cell marker CD31 in 65 cases of formalin fixed paraffin embedded gliomas. The relationship of BTSC distribution with micro-blood vessels was analyzed using morphometry.

METHODS

(1) The expression levels of Nestin and CD133 proteins were detected using SABC immunohistochemical analysis. Then we calculated the percentage of CD133(+) cells, CD133(+) blood vessels, Nestin(+) cells and Nestin(+) blood vessels among 65 tumors, grade II (n = 18), grade III (n = 23) and grade IV (n = 24), according to WHO 2000 classification of nervous system tumors. (2) Double immunofluorescence staining was used to detect the co-expressions of CD133/CD31, CD133/Nestin and Nestin/CD31. Then the correlation of two different marked cells with the corresponding positive vascular endothelial cells were determined.

RESULTS

CD133(+) cells and Nestin(+) cells could be observed in all glioma tissues. Furthermore they could also be observed expressing in the endothelial cells. In low-grade group, there were fewer CD133(+) blood vessels or Nestin(+) blood vessels in the regions which CD133(+)cells or Nestin(+) cells distributed compared with the high-grade group. The CD133(+)/CD31(+) and Nestin(+)/CD31(+) cells could be found co-expressed in the endothelial cells by using double immunofluorescence staining. Positive correlation was observed between the CD133(+) cells and CD133(+) blood vessels (r = 0.945, P < 0.01). It was similar to the correlation between the Nestin(+) blood vessels and Nestin(+) cells (r = 0.727, P < 0.01).

CONCLUSION

In gliomas, the endothelial cells express brain tumor stem cells markers. Therefore the capillaries in gliomas may come from the differentiation of BTSCs. And the BTSCs are accumulated around the capillaries. Along with the rank of tumor grades, positive correlation is observed between CD133(+) cells or Nestin(+) cells with the corresponding blood vessels.

Biological heterogeneity of putative bladder cancer stem-like cell populations from human bladder transitional cell carcinoma samples

Transitional cell carcinoma (TCC) is the most common type of bladder cancer. Emerging evidence has suggested that the capability of a tumor to grow and propagate is dependent on a small subset of cells, the cancer stem-like cells (CSCs) or tumor initiating cells. We report on the isolation and biological characterization of putative bladder CSC populations from primary TCCs. Isolated cells were induced to proliferate in stem cell culture conditions (serum-free medium containing mitogenic growth factors). The proliferating cells formed spheroids (urospheres) and their abilities for extensive proliferation and self-renewal were assayed. Their positivity for several stem cell markers (CD133, Oct-3/4, nestin, and cytokeratins) was also assessed by immunofluorescence tests and they could have the potential to differentiate in the presence of serum. In stem cell culture conditions they gradually showed loss of proliferation, adherence to the substrate, and morphological changes, which might reflect their progressive acquisition of differentiative capacity and loss of self-renewal ability. To evaluate if effective cell selection occurred after isolation, conventional cytogenetic studies on fresh chromosome spreads immediately after isolation and after culture were carried out. In addition, a molecular cytogenetic study by UroVysion assay was carried out on paraffin-embedded tissue sections and on fresh and after culture nuclei preparations. The data collected indicated important karyotype changes and a positive selection for hypo- or near-diploid cells, losing the complexity present in fresh tumors.

[Changes of differentiation and gene expression of CD133+ cells in human umbilical cord blood induced by SCF and bFGF]

This study was aimed to investigate the changes of differentiation and gene expression of CD133(+) cells in human umbilical cord blood induced by stem cell factor (SCF) and basic fibroblast growth factor (bFGF) in vitro, and to explore the biological characteristics of CD133(+) cells so as to provide experimental basis for potential use in regenerative medicine. The human umbilical cord blood CD133(+) cells were isolated from umbilical cord blood and purified by MACS magnetic selection. The CD133(+) cells were cultured in DMEM/F12 medium containing SCF, bFGF and B27 for 10 to 15 days. The total RNA of these cells was extracted before and after culture, and the analysis of related gene expression levels of these cells was performed using oligonucleotide microarrays. The results showed that out of 263 genes 21 genes were obviously up-regulated after culture than that before culture, whereas 7 genes were found to be significant down-regulated as compared with fresh-separated CD133(+) cells. These genes were involved in stem cell specific markers, cell cycle regulators, stem cell differentiation markers and signaling pathways that are important for stem cell maintenance. It is concluded that SCF and bFGF can induce differentiation of human cord blood CD133(+) cells through up- or down-regulation of specific genes. This study provides gene expression information for SCF and bFGF-induced human cord blood CD133(+) cells and contributes to understand the effect of SCF and bFGF on proliferation and differentiation CD133(+) cells at gene level, and promotes therapeutic applications of the CD133(+) cells induced by SCF and bFGF.

CD133+ circulating haematopoietic progenitor cells predict for response to sorafenib plus erlotinib in non-small cell lung cancer patients

BACKGROUND

Blood-based biomarkers may be particularly useful for patient selection and prediction of treatment response for angiogenesis inhibitors. Circulating endothelial cells (CECs) and haematopoietic progenitor cells (HPCs) might have a role in tumour angiogenesis and in tumour growth. Measurement of CECs and HPCs in the blood of patients could be a simple, non-invasive way to monitor or predict responses to treatment.

METHODS

(VEGFR2(+)) CECs(,) (CD133(+)) HPCs, plasma vascular endothelial growth factor (VEGF) and erythropoietin were measured in blood from 25 non-small cell lung cancer (NSCLC) patients before and during treatment with sorafenib plus erlotinib (SO/ER). In order to assess the drug specificity of changes in CECs and HPCs, 18 patients treated with bevacizumab plus erlotinib (BV/ER) and 10 patients with erlotinib (ER) monotherapy were studied. Response was measured in all patient groups by Response Evaluation Criteria in Solid Tumors (RECIST).

RESULTS

At day 7, SO/ER-treated patients showed a three-fold increase in CECs (P<0.0001) comparable to BV/ER-treated patients (P<0.01), and the CECs did not change with erlotinib treatment (P=0.8). At day 7, CD133(+)/HPCs decreased with SO/ER treatment (P<0.0001). HPC numbers did not change with either BV/ER or erlotinib. In SO/ER-treated patients pre-treatment CD133(+)/HPCs were significantly lower in responders (P=0.01) and pre-treatment CD133(+)/HPC numbers lower than the median correlated with a longer time-to-progression (TTP) (P=0.037).

CONCLUSION

Pre-treatment CD133(+)/HPCs are a promising candidate biomarker to further explore for use in selecting NSCLC patients who might benefit from SO/ER treatment.

Biomarkers: important clues to the pathogenesis of infantile haemangioma and their clinical significance

Infantile haemangioma is the most common tumour of infancy, yet the pathogensis of this lesion remains unknown and the predictable life cycle is poorly understood. Though much new information on infantile haemangioma has emerged over the past decade, researchers continue to debate the fundamental features; including cells of origin, nonrandom distribution, and mechanisms regulating the sometimes explosive growth and slow involution. The development of biomarkers has shed light on the pathogenesis and management of infantile haemangioma. Several useful biomarkers and their suggestions as to the aetiology of infantile haemangioma are reviewed. In addition, the application in clinical diagnosis and choice of treatment methods of infantile haemangioma is summarised.

[Generation and preliminary functional study of a CD133-2-harboring L929 cell line]

AIM

To generate an engineered L929 cell line harboring human CD133-2 and perform the functional study of the gene-modified cell line.

METHODS

The human CD133-2 gene was obtained by PCR from a cDNA library of foetus liver. After digested with Hind III and BamH I, the PCR product was cloned into pIRES2-EGFP vector. The recombinant plasmid CD133-2/pIRES2-EGFP was transfected into L929 cell line using lipofectamine, followed by G418 selection. RT-PCR, Western blot and flow cytometry (FCM) were used to detect the expression of CD133-2. MTT was used to analyze the effect of the CD133-2/L929 cells on proliferation of T cells. FCM was performed to monitor T cell activation by detecting T cell surface markers of CD4CD25 and CD8CD25 after T cells were cocultured with the CD133-2/L929 cells in the presence of an anti-CD3 mAb.

RESULTS

A stable cell line constitutively expressing the human CD133-2 was established successfully. In the presence of the anti-CD3 mAb, CD133-2/L929 cells caused inhibition of T cell proliferation and down-regulation of the activation markers of CD4CD25 and CD8CD25 on T cells.

CONCLUSION

The engineered CD133-2/L929 cell line provides a gain-of-function cell model for further understanding the biological role of CD133-2.

Isolation, characterization and mobilization of prostate cancer tissue derived CD133+ MDR1+ cells

Cancer stem cells undoubtedly exist in many tumor types, including the prostate. CD133 has recently been considered an important marker that represents the subset population of cancer stem cells. The purpose of the present study is to isolate CD133+ and CD133- cells from normal healthy volunteers and prostate cancer patients to check the prostate stem cells markers and chemokine receptors like CXCR4 for their mobilization. In this study we isolated CD133+ and CD133- cells using magnetic beads from prostate tissues and peripheral blood samples of normal healthy volunteers and prostate cancer patients (NV-CD133+, NV-CD133-, PC-CD133+ and PC-CD133-). The isolated cells were analyzed using flow cytometry and western blot analysis of MDR1, alpha2beta1, CD44, Oct-4 and CXCR4. PC-CD133+ cells displayed higher expressions of CD44, MDR1, Oct-4 and alpha2beta1 expressions with the ability to differentiate into prostate cancer cells. Furthermore, PC-CD133+, highly expressed the chemokine receptor CXCR4 and its ligand SDF1-alpha. Here we conclude that, PC-CD133+ displayed a higher expression of prostate stem cell markers like CD44, MDR1 and Oct-4 and chemokine receptor CXCR4 and its ligand SDF1-alpha in peripheral blood and prostate cancer tissue derived CD133+ cells The CXCR4 and SDF1-alpha expressions will have impact on the mobilization of prostate cancer stem cells (PC-CD133+ cells).

Medullary thyroid carcinoma cell lines contain a self-renewing CD133+ population that is dependent on ret proto-oncogene activity

CONTEXT

Medullary thyroid carcinoma (MTC) is a cancer of the parafollicular C cells commonly caused by an inherited or acquired RET proto-oncogene mutation. Therapeutic resistance and recurrence of the disease imply the presence of cancer stem cells in MTC.

OBJECTIVE

In this study, we sought to identify and characterize cancer stem cell-like cells in MTC.

MAIN OUTCOME MEASURES

The characterization of stem cell properties was performed using immunostaining, flow cytometry, sphere formation assay, rederivation assay, Western blotting, and quantitative RT-PCR of defined markers of neural stem and progenitor cells. The role of ret proto-oncogene activation was assessed through RNA interference knockdown.

RESULTS

CD133 positivity was identified by immunostaining patient MTC. Flow cytometry confirmed a subpopulation of CD133(+) cells in two MTC cell lines. The CD133(+) cells could be expanded by sphere formation assay, passaged multiple times, and expressed neural progenitor markers beta-tubulin 3 and glial fibrillary acidic protein. The MZ-CRC-1 cell line, which harbors a M918T RET mutation, had greater CD133(+) cell numbers and sphere-forming ability than the TT cell line, which harbors the less active C634W mutation. Sphere formation was more dependent on ret proto-oncogene activity than epidermal growth factor or fibroblast growth factor.

CONCLUSION

Our data support the existence of cancer stem-like cells in MTC, which exhibit the features of self-renewal and of multiple lineage differentiation that is dependent on ret proto-oncogene receptor activity. These findings may provide new insights to develop more promising therapy for MTC.

Endothelial progenitor cells in subclinical hypothyroidism: the effect of thyroid hormone replacement therapy

CONTEXT

Subclinical hypothyroidism (SCH) is associated with cardiovascular (CV) risk factors, and possibly CV disease. However, its management remains controversial. Endothelial progenitor cells (EPC), expressing both endothelial and stem cell markers, are known to offer a novel CV risk marker.

OBJECTIVE

The aim of the study was to ascertain whether EPC count or function is reduced in SCH and whether it improves with T(4) therapy.

DESIGN AND INTERVENTION

EPC were studied in peripheral blood by fluorescence-activated cell sorter and following in vitro cultures before and after T(4) together with CV risk factors in 20 SCH and healthy controls (HC).

MAIN OUTCOME MEASURE

EPC count was measured at baseline and after T(4) replacement in SCH.

RESULTS

EPC count was significantly reduced in SCH compared to HC: median (range)-CD133+/VEGFR-2+, 0.09 (0.02-0.44) vs. 0.47 (0.17-2.12), P < 0.001; CD34+/VEGFR-2+, 0.10 (0.04-0.46) vs. 0.39 (0.11-2.13), P < 0.001; whereas EPC function was similar. There was a significant positive correlation between CD133+/VEGFR-2+ with free T(4) levels (r = 0.38; P = 0.02); high-density lipoprotein cholesterol levels (r = 0.51; P = 0.001); and negative correlation with TSH concentrations (r = -0.64; P < 0.001). After adjustment for conventional CV risk factors, SCH predicted lower EPC count, beta coefficient/P value: CD133+/VEGFR-2+ (-0.77/<0.001), and CD34+/VEGFR-2+ (-0.71/<0.001). In SCH participants, EPC count increased and was similar to HC after T(4); CD133+/VEGFR-2+, 0.32 (0.03-0.94) vs. 0.09 (0.02-0.44), P < 0.001; and CD34+/VEGFR-2+, 0.26 (0.06-0.88) vs. 0.10 (0.04-0.46), P < 0.001.

CONCLUSION

SCH predicted lower EPC count, which improved with T(4) treatment, independent of other CV risk factors, providing additional evidence that T(4) replacement may improve CV risk in SCH.

Insulin-like growth factor binding proteins-2 and -4 enhance the migration of human CD34-/CD133+ hematopoietic stem and progenitor cells

The insulin-like growth factor (IGF) system is involved in cell migration, which plays an important role in cancer progression. It has been shown that cancer progression correlates with the level of circulating human hematopoietic stem and progenitor cells (HSPCs) expressing CD34 and/or CD133. However, it is unknown whether factors released from cancer cells, including soluble compounds of the IGF system, recruit these HSPCs via enhancing their migration. Our study showed the expression of type I IGF receptor (IGF-IR) in human HSPCs expressing CD34 and/or CD133. In an indirect co-culture model, soluble factors released from human lung epithelial cancer cells (H358, H322) increased the migration of CD34-/CD133+ cells towards cancer cells, whereas migration of CD34+/CD133+ or CD34+/CD133- cells remained unchanged. The lung epithelial cancer cell lines H358 and H322, exhibited a high expression of IGFBP-2, -4 and -6 but not IGF-I and IGFBP-3. Subsequent analyses with those soluble compounds of the IGF system revealed a dose-dependent stimulating effect of the IGFBP-2 and -4 on the migration of CD34-/CD133+ cells. In contrast, IGF-I and IGFBP-3 and -6 did not influence the migration of CD34-/CD133+ cells. Because IGFBPs are involved in cell migration via IGF-dependent and -independent mechanisms, our study indicates that IGFBP-2 and -4, which are expressed in lung epithelial cancer cells, enhance the migration of CD34-/CD133+ HSPCs independent of IGF-I.

Stemness characteristics of fibrolamellar hepatocellular carcinoma: immunohistochemical analysis with comparisons to conventional hepatocellular carcinoma

The involvement of cancer stem cells (CSC) in tumorigenesis has been studied in several malignancies, but their presence in fibrolamellar hepatocellular carcinoma (FLHCC) has not previously been evaluated. General characteristics of "stemness" include the expression of putative stem cell antigens, reduced cell cycle progression, and limited functional differentiation or dedifferentiation under the influence of the microenvironment. Immunohistochemical probes applied to 8 archival cases of FLHCC vis-à-vis contiguous non-neoplastic parenchyma, which was present in 5 cases, revealed such stemness characteristics by showing: (a) stem cell antigens, with moderate to intense expression of CD133 in the cytoplasm (6 of 8 FLHCC cases and comprising >40% of the tumoral areas) and of CD44 on the plasmalemmal aspect (7 of 8 FLHCC cases and comprising 50 to 95% of the tumor cells), vs foci of such overexpressions in only 1 of 5 of the contiguous liver parenchyma (p = 0.053 and p = 0.015, respectively); (b) limited G1 to S phase progression ( <1 % of tumor cells with nuclear S phase kinase-associated protein [Skp]2 expression); and (c) dedifferentiation or reduced functional differentiation in the form of minimal to absent expression of a differentiation-associated marker, peroxisomal proliferator-activator receptor (PPAR)-gamma in tumoral nuclei and loss of plasmalemmal expression of beta-catenin in 6 of 8 FLHCC cases vs expression of these proteins in the non-neoplastic, differentiated hepatocytes in 5 of 5 and 4 of 5 cases, respectively, in contiguous liver parenchyma (p <0.01 and p = 0.053, respectively). In contrast, only 1 of 11 cases of well-differentiated, conventional hepatocellular carcinoma (HCC) showed mild to moderate expression of CD133 in the cytoplasm, but with the majority (8 of 11) showing occasional nuclear expression. Similarly, only 3 of 11 cases of conventional HCC expressed plasmalemmal CD44. Notably, 11 of 11 cases of conventional HCC expressed beta-catenin on the plasmalemmal aspect of the tumor cells, and 3 of 11 showed nuclear translocation. These findings in conventional HCC were significantly different from those in FLHCC (p = 0.003, 0.009, and 0.0005, respectively). This study provides evidence of stemness in FLHCC and discusses the implications of stemness in the histogenesis of FLHCC vs conventional, well-differentiated HCC.

Umbilical cord blood stem cells: induction of differentiation into mesenchymal lineages by cell-cell contacts with various mesenchymal cells

CD133(+) cells isolated from bone marrow, peripheral blood, or umbilical cord blood (UCB) represent an established source of transplantable hematopoietic progenitors. Further, there is increasing evidence that such CD133(+) cell isolates comprise subpopulations capable of differentiating into several mesenchymal lineages. In this study, we investigated conditions under which mesenchymal differentiation can be induced, particularly the role of cell-cell contacts with mesenchymal cells. A purified, nearly homogeneous CD133(+) population of human UCB cells was expanded by stimulation with platelet-derived growth factor and epidermal growth factor, labeled with the fluorescent marker DiI and cocultivated with rat osteoblasts, C2C12 myoblasts, or rat cardiomyocytes, respectively. In control experiments, the two cell types were separated by microporous membranes to avoid cell-cell contacts. Direct coculture of DiI-labeled UCB cells with the different mesenchymal cell populations resulted in both significant morphological changes and upregulation of lineage-specific markers. Expression of osteocalcin, myosin heavy chain, or alpha-actinin confirmed differentiation of the UCB cells into an osteoblastic, myoblastic, or cardiomyocytic phenotype, respectively. In contrast, coculture of UCB cells with the respective inducer cells under conditions preventing cell-cell contacts yielded minor, if any, evidence for such differentiation. Our data, thus, indicate that UCB cell expansion in vitro and subsequent direct cell-cell contacts with mesenchymal cells can induce their differentiation into mesenchymal lineages specific to the cell type they are in contact with. This finding has important implications for understanding the homing of adult stem cells and the promise of UCB as a cell source for tissue engineering and regenerative medicine.

Maintenance of HCT116 colon cancer cell line conforms to a stochastic model but not a cancer stem cell model

The cancer stem cell (CSC) model, in which a small population of cells within a tumor possesses the ability to self-renew and reconstitute the phenotype of primary tumor, has gained wide acceptance based on evidence over the past decade. It has also been reported that cancer cell lines contain a CSC subpopulation. However, phenotypic differences between CSCs and non-CSCs in cancer cell lines are not better defined than in primary tumors. Furthermore, some cell lines do not have a CSC population, revealed as a side population and expression of CD133. Thus, the identification of CSCs in cancer cell lines remains elusive. Here, we investigated the CSC hierarchy within HCT116 colon cancer cells, which do not have a CD133-positive subpopulation. We examined the expression of alternative CSC markers epithelial specific antigen (ESA) and CD44 in floating-sphere-derived cells, which are known to be the cells of enriching CSCs. Sphere-derived HCT116 cells exhibited heterogeneous expression of ESA and CD44. The two major subpopulations of HCT116 sphere cells (ESA(low)CD44(-/low) and ESA(high)CD44(high)) exhibited a biological/proliferative hierarchy of sphere-forming and soft agar colony-forming activity. However, there was no difference between the two subpopulations in the incidence of xenograft tumors. When ESA(low)CD44(-/low) cells were allowed to aggregate and re-form floating-spheres, the biological/proliferative hierarchy of parental HCT116 spheres was reconstituted, in terms of ESA and CD44 expression. Thus, HCT116 cells have plasticity when they are set in floating-spheres, suggesting that maintenance of the HCT116 cell line conforms to a stochastic model, not a CSC model.

[Autologous stem cell therapy with surgical myocardial revascularization - The Rostock University experience]

OBJECTIVE

Stem cell therapy has gained great attraction in the treatment of acute and chronic myocardial diseases in recent years. The aim was to evaluate our experience in light of the middle term results of intramyocardial stem cell treatment with concomitant coronary artery bypass surgery (CABG) since 2001.

METHODS

After encouraging initial results of the Phase I (safety) trial with the first 15 patients, a prospective, controlled Phase II (efficacy) study was begun with 40 patients aiming to determine functional benefit of stem cell treatment using bone marrow derived CD 133+stem cell therapy with concomitant CABG in comparison to CABG only since 2003. Medium-term results of intervention were evaluated using patient's clinical findings, Holter monitoring, echocardiography, magnetic resonance imaging, computed tomography and myocardial scintigraphy. Statistical analyses were performed using unpaired t, Mann-Whitney U, ANOVA for repeated measurements and Chi-square tests.

RESULTS

Left ventricular ejection fraction (LVEF) has increased significantly at 6th and 18th months follow-up in the first 15 patients who received therapy since 2001 (preoperative: 39.0+/- 8.7%; 6th month: 50.2+/- 8.5% and 18th month: 47.9+/- 6.0%; p=0.012). In the late group of patients, LVEF increased from 37.4+/- 8.4% to 47.1+/- 8.3% (p<0.001) whilst although an increase in LVEF has been observed in the CABG alone group (from 37.9+/- 10.3% to 41.3+/- 9.1%) the increase has not been statistically significant. Mortality occurred in 2 patients [1 patient from the early and 1 patient from the medium term follow-up] due to non-cardiac reasons. Myocardial calcification, lethal ventricular arrhythmia, and tumor formation have not been observed in any of the patients in the long-term follow up.

CONCLUSION

Direct injection of bone marrow derived CD 133+ stem cells into the myocardium with concomitant CABG is safe. However, this treatment modality may only be applied as standard treatment after completion of the long- term detailed results of prospective, randomized multicenter trials.