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Pierre Validire

Publications and source records attributed to Pierre Validire.

At least 19 recordsLinked to original sources
PubMed2007

BCAR1 expression in prostate cancer: association with 16q23 LOH status, tumor progression and EGFR/KAI1 staining.

BACKGROUND: The 16q23 locus has been recently suggested in both breast and prostate cancer to contain a gene involved in disease progression. The breast cancer antiestrogen resistance 1 (BCAR1) gene, located at 16q23, contributes to many cellular processes including migration and survival, and interacts in vitro with the growth factor receptor EGFR and the metastasis suppressor KAI1. METHODS: BCAR1, EGFR, and KAI1 expression was studied by immunohistochemistry on a tissue microarray containing 100 localized prostate cancers (LPC), 15 hormone refractory prostate cancers (HRPC), and 15 lymph node metastasis (LNM). Forty eight of the LPC were also analyzed for 16q23 LOH status using microsatellite markers. RESULTS: BCAR1 staining was present in 25% of LPC, associated with higher Gleason score, and in 60% and 80% of, respectively, LNM and HRPC. BCAR1 expression was inversely correlated with 16q23 LOH status (P < 0.001), and was associated with high EGFR staining (P < 0.02), and negative KAI1 expression (P < 0.01). CONCLUSIONS: BCAR1 expression in LPC seems to be regulated at least in part by genetic events. The increased expression of BCAR1 with disease progression suggests a potential interest for both prognosis and treatment.

Aged↗
PubMed2007

Establishment of human colon cancer cell lines from fresh tumors versus xenografts: comparison of success rate and cell line features.

Obtaining representative human colon cancer cell lines from fresh tumors is technically difficult. Using 32 tumor fragments from patients with colon cancer, the present study shows that prior xenograft leads to more efficient cell line establishment compared with direct establishment from fresh tumors (P < 0.05). From 26 tumor specimens, we successfully established 20 tumor xenografts in nude mice (77%); among 19 of these xenografts, 9 (47%) led to cell lines, including four from liver metastases. Only 3 of 31 tumor specimens (9.7%) grew immediately in vitro, and all were derived from primary tumors. To compare major phenotypic and genotypic characteristics of human colon cancer cell lines derived from the same tumor fragment using two protocols, the two pairs of cell lines obtained from 2 of 32 tumor fragments were extensively studied. They displayed similar morphology and were able to form compact spheroids. Chemosensitivity to 5-fluorouracil, CPT11, and L-OHP differed between cell lines obtained from patient tumors and those derived from xenografts. Matched cell lines shared a common core of karyotype alterations and distinctive additional chromosomal aberrations. Expression levels of genes selected for their role in oncogenesis evaluated by real-time quantitative PCR were found to be statistically correlated whatever the in vitro culture model used. In conclusion, xenotransplantation in mice of tumor fragments before establishment of cell lines enables generation of more novel human cancer cell lines for investigation of colon cancer cell biology, opening up the opportunity of reproducing the diversity of this disease.

Animals↗
PubMed2006

Cytokeratin 19 fragments in patients with acute lung injury: a preliminary observation.

OBJECTIVE: Cytokeratin 19 (CK19) is a specific cytoskeletal structure for alveolar epithelium. We hypothesized that the levels of CK19 fragments in bronchoalveolar lavage (BAL) fluid could serve as an index of epithelial injury and as a prognosis marker in patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). The aims of our study were, in patients with ALI/ARDS: (1) to measure CK19 fragments concentrations in BAL fluid, (2) to assess its prognostic value, and (3) to identify the cellular source of CK19 in the alveolar space. DESIGN: Prospective preliminary study. SETTING: University hospital surgical ICU. PATIENTS: Twenty-two mechanically ventilated patients with ALI/ARDS and 10 non-ventilated control patients. Plasma samples were obtained for 11 ALI/ARDS patients. MEASUREMENTS AND RESULTS: The concentration of BAL CK19 fragments was higher in patients (median 4916 pg/ml, 25th-75th percentile 2717-10533) than in controls (2208 pg/ml. 767-3923; p =0.05), and higher in 10 non-survivors (7051 pg/ml, 4372-13371) than in 12 survivors (2888 pg/ml, 1315-5639; p =0.03 among ALI/ARDS patients). BAL CK19 fragment concentration did not correlate with simplified acute physiologic score, lung injury score or PaO(2)/FIO(2) ratio, but correlated positively with BAL albumin concentration (p =0.002) and with number of BAL macrophages (p=0.0001). Plasma CK19 fragment concentrations were 10 times lower than those in BAL. Immunohistochemical staining for CK19 showed a strong labelling of injured detached epithelial cells and hyperplastic epithelium in ALI/ARDS lung samples. CONCLUSION: CK19 fragment concentrations were found to be elevated in BAL fluid in ALI/ARDS patients compared with control subjects. High BAL CK19 fragment levels were associated with a poor prognosis.

Bronchoalveolar Lavage Fluid↗
PubMed2006

Ultraviolet-induced autofluorescence characterization of normal and tumoral esophageal epithelium cells with quantitation of NAD(P)H.

Cellular autofluorescence was characterized in normal human esophageal cells and in malignant esophageal epithelial cells. The study was performed under excitation at 351 nm where the cell fluorescence is mainly due to the reduced pyridine nucleotides (NAD(P)H) with a very small contribution from the oxidized flavins (FMN, FAD) or lipopigments. The autofluorescence emission of squamous cell carcinoma, adenocarcinoma on Barrett's mucosa and normal cells was characterized by microspectrofluorimetry on monolayers and by spectrofluorimetry on cell suspensions. The relative contribution of each fluorophore to the fluorescence emission of the different cell types was evaluated by a curve-fitting analysis. A statistically highly significant difference was observed between the average intensity of the raw spectra of the different cell types. Tumoral cells had a fluorescence intensity approximately twice as high as that of normal cells. The results of the NAD(P)H quantitation analyzed by microspectrofluorimetry on single living cells and spectrofluorimetry on cell suspensions were consistent with those obtained by biochemical cycling assays, showing that the amount of intracellular NAD(P)H is higher in tumoral cells than in normal cells. Bound NAD(P)H concentration was found to be quite stable whatever the cell type while the amount of free NAD(P)H showed a very important increase in tumoral cells.

Barrett Esophagus↗
PubMed2006

Follicular dendritic cell tumor of the mediastinum: expression of fractalkine and SDF-1alpha as mast cell chemoattractants.

Follicular dendritic cell tumor (FDCT) is a rare tumor mainly located in laterocervical lymph nodes. We report one case of mediastinal FDCT associated with a history of bullous skin disease and clinically obvious immunosuppression. This tumor was characterized by heavy mast cell infiltration. Mast cells were in close relationship with tumor cells as demonstrated by ultrastructural examination and their presence are probably related with the strong expression of mast cell chemoattractants as fraktalkine and stromal cell-derived factor-1alpha by tumor cells. The long follow-up period of more than 17 years allowed to us assess the relatively indolent evolution of this tumor characterized by three slowly growing local recurrences without metastasis.

Antigens, CD↗
PubMed2006

[Morbidity/mortality reviews: assessment of their implementation in one hospital].

OBJECTIVES: The objective of this study was to describe the steps involved in establishing a morbidity/mortality review committee (MMRC) to analyze the causes of avoidable deaths or life-threatening complications and the development of plans and protocols to avoid their recurrence. METHODS: The MMRC included physicians from each hospital department. Each member was responsible for organizing departmental meetings to analyze its avoidable deaths and life-threatening complications. RESULTS: During its meetings three times a year, the MMRC developed a method for analysis of these serious events. Each department organized 3 (range: 1-12) meetings a year and analyzed 1-3 cases at each. Over 30 months, 35,817 patients were admitted to the hospital and 341 (1%) died. The unexpected mortality rate varied by department and specialty (median: 27%, range: 6-65%). In all, 92 cases were referred to MMRC meetings (27%; range: 6-70% of hospital deaths), and 30% of them involvement nosocomial diseases. Heart disease was the primary cause of unexpected deaths. DISCUSSION: The principal improvements involved medical and surgical strategies, surgical techniques, drug prescriptions, and patient monitoring.

Aged↗
PubMed2006

Influence of endothelial cells on vascular smooth muscle cells phenotype after irradiation: implication in radiation-induced vascular damages.

Damage to vessels is one of the most common effects of therapeutic irradiation on normal tissues. We undertook a study in patients treated with preoperative radiotherapy and demonstrated in vivo the importance of proliferation, migration, and fibrogenic phenotype of vascular smooth muscle cells (VSMCs) in radiation-induced vascular damage. These lesions may result from imbalance in the cross talk between endothelial cells (ECs) and VSMCs. Using co-culture models, we examined whether ECs influence proliferation, migration, and fibrogenic phenotype of VSMCs. In the presence of irradiated ECs, proliferation and migration of VSMCs were increased. Moreover, expressions of alpha-smooth muscle actin, connective tissue growth factor, plasminogen activator inhibitor type 1, heat shock protein 27, and collagen type III, alpha 1 were up-regulated in VSMCs exposed to irradiated ECs. Secretion of transforming growth factor (TGF)-beta1 was increased after irradiation of ECs, and irradiated ECs activated the Smad pathway in VSMCs by inducing Smad3/4 nuclear translocation and Smad-dependent promoter activation. Using small interferring RNA targeting Smad3 and a TGFbeta-RII neutralizing antibody, we demonstrate that a TGF-beta1/TGF-beta-RII/Smad3 pathway is involved in the fibrogenic phenotype of VSMCs induced by irradiated ECs. In conclusion, we show the importance of proliferation, migration, and fibrogenic phenotype of VSMCs in patients. Moreover, we demonstrate in vitro that ECs influence these fundamental mechanisms involved in radiation-induced vascular damages.

Actins↗
PubMed2005

Allelic loss at 16q23.2 is associated with good prognosis in high grade prostate cancer.

PURPOSE: Loss of heterozygosity (LOH) at 16q23.2 is an early and frequent event in prostate cancer. LOH is thought to be involved in tumor development and progression mainly through inactivation of tumor suppressor genes. However, it has been demonstrated that LOH at 16q23.2 is an independent marker of good prognosis in breast cancer. In the present study, we evaluated the clinical relevance of 16q23.2 LOH in prostate cancer, together with other LOH frequently associated with this disease. EXPERIMENTAL DESIGN: Tumoral and normal DNA were extracted from 61 radical prostatectomies, including 30 pT2 tumors with low Gleason score 5,6 (group 1), and 31 pT3 high grade (G8-9) tumors (group 2). Median follow-up after surgery was 42 months. Three patients reccured in group 1, and 20 in group 2. LOH analysis was performed using highly informative microsatellites markers, at 16q23.2, and at other chromosome loci frequently deleted in prostate cancer: 7q31, 8p22, 12p13, 13q14, and 18q21. RESULTS: LOH at 16q23.2 is associated with low stage low grade tumors and lower preoperative PSA, while LOH at 8p22 is more frequent in high stage high grade prostate cancer. In group 2, 16q23.2 LOH was the only predictor of disease-free survival in univariate and multivariate analysis, and the cumulative LOH rate was not higher in patients non-deleted for 16q23.2. CONCLUSION: These results emphasize the interest of 16q23.2 as an independent prognostic factor in high-grade prostate cancer, and suggest that this chromosomal region may contain a gene involved in tumor progression.

Aged↗
PubMed2005

Tissue microarray analysis of the prognostic value of E-cadherin, Ki67, p53, p27, survivin and MSH2 expression in upper urinary tract transitional cell carcinoma.

OBJECTIVES: Invasive upper urinary tract transitional cell carcinoma (UUT-TCC) has a poor prognosis (survival <50% at 5 years), and tumor stage and grade often fail to predict outcome. Our purpose was to establish whether the expression of Ki67, p53, p27, E-cadherin, survivin or MSH2 can provide prognostic information in UUT-TCC. METHODS: The following data from the files of 62 patients treated for UUT-TCC over 12 years were collated: age at diagnosis, prior history of cancer, tobacco consumption, tumor stage (including surgical margins) and grade, and disease progression. Immunohistochemistry (IHC) for Ki67, p53, p27, E-cadherin, survivin and MSH2 was performed on tissue microarray sections from tumor tissue. RESULTS: Overall, 31 patients died with metastasis from UUT-TCC. Mean survival was 20+/-16 months (range 2-83). In a univariate analysis, advanced age (>68 years), high stage, and loss of E-cadherin and high Ki67 expression were associated with a poor prognosis and disease recurrence. In a multivariate analysis, the independent factors of prognosis and recurrence were E-cadherin (p=0.001; p=0.004), age (p=0.022; p=0.008), and high stage (p=0.023; p=0.008). CONCLUSIONS: E-cadherin is a useful independent prognostic factor in UUT-TCC, for use in addition to age and tumor stage. It is of particular interest to predict recurrence in patients with low grade non-invasive tumors. Ki67 expression is informative but less significant. Survivin, p53, p27 and MSH2 have no prognostic value.

Aged↗
PubMed2005

Differential expression of 37 selected genes in hormone-refractory prostate cancer using quantitative taqman real-time RT-PCR.

Progression of prostate cancer to androgen independence remains the primary obstacle to improved survival. The development of more effective treatments depends on our understanding of the molecular events associated with the hormone-refractory stage. We quantified, among 90 screened genes, the expression of 37 target genes, using real-time quantitative RT-PCR. Gene expression was studied in 13 samples of HPRC compared to 33 clinically localised cancers and normal prostate tissue. We identify 19 genes with significant differential expression in HRPC compared to localised prostate cancer. Genes with decreased expression included receptors for growth factors, MMR genes and the serine protease hepsin. Analysis of increased gene expression confirmed the importance of AR upregulation and highlighted genes not previously linked to HRPC, including enzymes involved in steroid synthesis and the antiapoptotic factor survivin. Progression of prostate cancer to the hormone-refractory state is associated with differential gene expression, which may prove useful for both understanding disease progression and the development of new therapeutic approaches.

Androgens↗
PubMed2005

Epidermal growth factor receptor, HER-2/neu and related pathways in lung adenocarcinomas with bronchioloalveolar features.

Lung adenocarcinomas with bronchioalveolar features (ABAF), formerly called bronchioloalveolar cancers (BAC), constitute a distinct clinical, radiological and pathological entity among lung malignancies. Epidermal growth factor receptor (EGFR) and to a less extent, HER-2/neu, are known to be overexpressed in non-small lung cancers, but their exact status in ABAF is not well-documented. Stimulation of these two receptors results in the initiation of two major cascades, namely phosphatidylinositol 3-kinase (PI-3K) and Ras-dependent pathways. We have therefore studied the expressions of EGFR, HER-2/neu as well as phosphorylated AKT (pAKT) and phosphorylated extracellular-signal regulated kinase (ERK), which are key molecules in these two pathways, in 15 ABAF patients. EGFR was found to be overexpressed in 9 of 15 patients (60%). HER-2/neu overexpression was detected in 6 of the 14 tumors tested (43%). pAKT and pERK were both found to be positive in 13 of 15 patients (87%). Six of the seven tumors with mucinous pattern were negative for EGFR, while all of the other eight cases were positive (P=0.001). Mucinous tumors were also less likely than non-mucinous tumors to overexpress HER-2/neu (17% versus 63%, respectively). These findings suggest that ABAF, particularly those with non-mucinous histology, commonly harbors EGFR and HER-2/neu overexpression. PI-3K and Ras-dependant pathways that lie downstream are generally activated, even in the absence of EGFR and/or HER-2/neu overexpression. ABAF may be a particularly promising candidate for EGFR-targeted strategies and this possibility merits extensive evaluation in clinical trials.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed2005

Pre-operative predictive factors of early recurrence after resection of adenocarcinoma of the esophagus and cardia.

OBJECTIVES: To determine pre-operative predictive factors of early recurrence in patients with esophageal and cardial adenocarcinoma. PATIENTS AND METHODS: We retrospectively analyzed consecutive patients who underwent resection for esophageal and cardial adenocarcinoma in our institution between October 1992 and October 2001. Patient files were studied and classified according to the occurrence of early recurrence (within one year) (group A) and patients without recurrence (group B). Pre-operative clinical, biological and radiological parameters were recorded. Both groups were compared in univariate and multivariate analysis. RESULTS: One hundred patients underwent surgical resection. Tumor was located in lower esophagus in 71 cases and at the cardia in 29 cases. R0 resection was feasible in 95 cases. Hospital mortality was 2%. Survival rate at 3 years was 56%. Recurrence before 1 year occurred in 28 patients (group A) and not in 72 (group B). In univariate analysis, younger age (P=0.01), dysphagia (P=0.04) and percentage of weight loss (P<0.0004) were significantly different between both groups. Weight loss more than 10% was observed in 2 patients of group B, and in 9 patients of group A. In multivariate analysis, weight loss more than 10% was the only pre-operative factor associated with early recurrence (P=0.018). CONCLUSION: Important weight loss could be a pre-operative predictive factor of early recurrence after resection of esophageal and cardial adenocarcinoma and surgery as first line treatment could be avoided in these patients.

Adenocarcinoma↗
PubMed2004

Moderate and chronic hemodynamic overload of sheep atria induces reversible cellular electrophysiologic abnormalities and atrial vulnerability.

OBJECTIVES: The aim of this study was to evaluate the myocardial consequences of a chronic volume overload of the left atrium (LA). BACKGROUND: Atrial dilation is a major risk factor for atrial fibrillation (AF), but the underlying mechanisms are poorly understood. METHODS: A left-right aorto-pulmonary artery shunt (APS) was created in sheep. The cardiopathy was characterized by echocardiography, electrophysiologic testing, and histologic analysis. Cellular action potential (AP) and calcium current (I(Ca)) were recorded by means of microelectrode and patch clamp techniques. RESULTS: Three to four months after surgery, all animals in the APS state had a dilated LA (146.2 +/- 35.4 cm(2)/m(2) vs. 91.7 +/- 10.4 cm(2)/m(2) in the control state; p = 0.0024) but remained in sinus rhythm. Repetitive atrial firing was triggered by a single extra beat in five of six animals in the APS state and in two of six animals in the control state. Moreover, in two animals in the APS state, a single extra beat triggered sustained AF. Myocytes were enlarged and 39.8% showed some degree of myolysis. In animals in the APS state, the AP had no plateau phase or small amplitude and numerous myocytes were unexcitable. The I(Ca) density was 45.2% lower in APS animals than in control animals. Beta-adrenergic stimulation normalized I(Ca) and restored the plateau phase of the AP. After shunt suppression, the electrophysiologic properties of the atria returned to normal. CONCLUSIONS: The APS induced moderate, isolated LA dilation, which was sufficient to cause major changes in cellular electrophysiologic properties and to render the atria vulnerable to fibrillation. These effects were reversed by shunt suppression.

Action Potentials↗
PubMed2004

Uncertain benefit from surgery in patients with lung metastases from breast carcinoma.

BACKGROUND: Isolated lung metastases have been reported to occur in 10-20% of all women with breast carcinoma. The authors described a series of patients who underwent surgery for lung metastases from breast carcinoma. METHODS: They reviewed the files of 125 consecutive patients who underwent surgery with a curative intent for lung metastases from breast carcinoma between 1972 an 1998 at a single institution. Survival curves were plotted by the Kaplan-Meier method. Prognostic factors were identified using the log-rank test and a Cox proportional hazards model for univariate and multivariate analyses, respectively. RESULTS: The median age at surgery was 53 years. There was a median of 1 resected metastasis (range, 1-16 resected metastases). The median size of the largest metastasis was 19 mm (range, 5-70 mm). The median disease-free interval (DFI) was 3 years. The median follow-up time after surgery was 8.5 years (range, 25 days to 22 years). The 3-year, 5-year, and 10-year probabilities of survival were 58% (95% confidence interval [95% CI], 49-67%), 45% (95% CI, 36-55%), and 30% (95% CI, 21-41%), respectively. The median survival time after surgery was 4.2 years. Complete resection was achieved in 96 patients. The quality of the resection (complete vs. incomplete) was not a statistically significant prognostic factor by univariate analysis and there was no significant difference between these two groups in terms of adjuvant postoperative therapy. The characteristics of the primary tumor and the number of metastases (one vs. two or more) had no detectable influence on survival. The size of the largest metastasis (> 20 mm or < or = 20 mm) and the DFI (< or = 3 years vs. > 3 years) were highly significant prognostic factors (P = 0.006 and P = 0.003, respectively). This was confirmed by multivariate analysis. Patients with a DFI < or = 3 years and/or the largest metastasis > 20 mm reportedly had a poor outcome (median survival, 2.6 years vs. 8.5 years for patients with none of these poor prognostic factors). CONCLUSIONS: Resection of lung metastases from breast carcinoma was associated with a significant 5-year survival rate of 45%. Whether these encouraging findings resulted from the surgical procedure itself or the preoperative selection of patients remained uncertain. When surgery is considered in this setting, the size of the largest metastasis and the DFI should be taken into account.

Adult↗
PubMed2004

Molecular profiling of benign prostatic hyperplasia using a large scale real-time reverse transcriptase-polymerase chain reaction approach.

PURPOSE: Benign prostatic hyperplasia (BPH) is characterized by a hyperplastic growth of epithelial and stromal cells in the prostate. Despite the high prevalence of the disease little is known regarding the molecular etiology of BPH. Therefore, a comparison of gene expression patterns between normal prostate, BPH and prostate cancer could provide insights into the pathogenic mechanisms of the disease and identify candidate genes that could be targeted for therapeutic use. MATERIALS AND METHODS: Prostate tissue specimen were obtained from 30 patients undergoing adenomectomy for BPH. Adenoma weight was less than 60 gm in 15 patients and more than 60 gm in the remainder. Normal prostate tissue was obtained from 15 patients undergoing radical prostatectomy for cancer from areas selected for absent tumor and BPH. Two pools of organ confined prostate cancer were also analyzed. We quantified in the 5 pools of tissues the expression of 327 genes using real-time quantitative reverse transcriptase-polymerase chain reaction. RESULTS: A total of 23 genes showed increased expression in BPH with a fold change of at least 2.5 between normal prostate and the 2 BPH groups, of which most were normal or down-regulated in prostate cancer. Seven genes showed decreased expression in BPH with a fold change of at least 3.5 between normal prostate and BPH. Most of them were also normal or down-regulated in prostate cancer. CONCLUSIONS: We identified a set of genes up-regulated in BPH compared to normal prostate tissue and often prostate cancer, including genes previously implicated in BPH and others not previously linked to this disease to our knowledge. Further investigations are now warranted to determine the clinical relevance and therapeutic potential of these genes.

Aged↗
PubMed2004

Impact of margin size on the incidence of local residual tumor after laparoscopic radical prostatectomy.

PURPOSE: Since October 2001 we have performed intraoperative frozen section (IFS) on the posterolateral areas of the radical prostatectomy specimen with bilateral nerve sparing. In cases of positive surgical margin (SMs) the corresponding neurovascular bundle (NVB) was resected. We evaluated the impact of several biological and pathological parameters on the incidence of local residual tumor in the NVB. MATERIALS AND METHODS: A total of 487 laparoscopic radical prostatectomies with bilateral nerve sparing and IFS were performed between October 2001 and December 2003. When IFS was positive, the whole NVB was removed and analyzed after fixation in serial sections. The size of the positive SM was measured in its largest dimension. The association of NVB residual tumor with positive SM size, preoperative prostate specific antigen, pathological stage and Gleason score was analyzed using the t and chi-square tests, and logistic regression. RESULTS: Of the 487 patients 84 had a positive SM on IFS. In 25 of the 84 additionally resected NVBs we found residual tumor. On univariate and multivariate analysis the only predictor of residual tumor was positive SM size (p<0.001). In all cases of a positive SM of 0.1 cm or less we found no residual tumor cells in the NVB. CONCLUSIONS: In case of a positive SM in the posterolateral area of the prostatectomy specimen margin size is predictive of the incidence of residual tumor in the corresponding NVB. This finding could help management and the decision about local adjuvant treatment.

Adult↗
PubMed2003

A three-dimensional tumor cell defect in activating autologous CTLs is associated with inefficient antigen presentation correlated with heat shock protein-70 down-regulation.

We described previously a CTL clone able to lyse the autologous carcinoma cell line IGR-Heu after specific recognition of an HLA-A2/mutated alpha-actinin-4 peptide complex. Here, we used IGR-Heu, cultured either as standard two-dimensional monolayers or as three-dimensional spheroids, to further analyze the influence of target architecture on CTL reactivity. Interestingly, we found that changes in the tumor structure from two- to three-dimensional induced a dramatic decrease in its capacity to activate autologous CTL, as measured by IFN-gamma and tumor necrosis factor-alpha secretion. These functional alterations were attributable neither to MHC class I expression nor to tumor antigen (Ag) down-regulation, because IGR-Heu, cultured as two- or three-dimensional, expressed similar levels of HLA-A2 and alpha-actinin-4. More importantly, incubation of three-dimensional cells with synthetic epitope completely restored cytokine release by CTL. This defective Ag presentation correlated with a decrease in heat shock protein (hsp)70 expression by three-dimensional tumors compared with two-dimensional cells. Furthermore, transfection of the tumor cells with hsp70 cDNA completely restored the Ag-presenting potential of spheroids and, therefore, cytokine production by T cells. These data strongly suggest that hsp70 down-regulation in three-dimensional cells may result in tumor resistance to the immune response.

Antigen Presentation↗