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Biomedical subjects

K Fizazi

Publications and source records attributed to K Fizazi.

At least 19 recordsLinked to original sources
PubMed2006

A phase II monocentric study of oxaliplatin in combination with gemcitabine (GEMOX) in patients with advanced/metastatic transitional cell carcinoma (TCC) of the urothelial tract.

BACKGROUND: The aim of the study was to evaluate the activity and the safety of the gemcitabine-oxaliplatin (GEMOX) combination as first-line treatment in advanced/metastatic transitional cell carcinoma (TCC) of the urothelial tract. MATERIALS AND METHODS: Patients with metastatic or unresectable TCC, PS < or =2, creatinine < or =1.5 upper limit of normal range (UNL) and measurable disease according to RECIST criteria were treated with a combination of gemcitabine (1500 mg/m(2)) followed by oxaliplatin (85 mg/m(2)) on day 1 and 15 of a 28-day cycle. RESULTS: A total of 123 cycles were administered to 30 patients (median 4, range 1-8). Three complete responses (CR) and 11 partial responses (PR) were observed. Overall response rate (ORR) was 47% (95% CI 28% to 66%). Median overall survival (OS) was 15 months (95% CI 8-31). Grade 3 and 4 neutropenia were reported in three and one patient, respectively; grade 3 anaemia in three patients; grade 3 and 4 thrombocytopenia in two and one patient, respectively; grade 1, 2 and 3 peripheral neuropathy in 14, 11 and two patients, respectively; grade 2 and 3 fatigue in 13 and seven patients respectively. CONCLUSIONS: The GEMOX combination is active in advanced/metastatic TCC with minimal toxicity and needs to be evaluated in a selected population of unfit patients and compared with other non-cisplatin-containing regimens.

Aged↗
PubMed2005

The risk of thrombo-embolic events is increased in patients with germ-cell tumours and can be predicted by serum lactate dehydrogenase and body surface area.

The aim of this study was to evaluate the risk of thrombo-embolic events (TEE) in patients with germ-cell tumours (GCT) who receive cisplatin-based chemotherapy, to compare this risk to that of a matched control group of non-GCT cancer patients, and to identify risk factors of TEE. The rate of TEE during the 6 months following the initiation of chemotherapy was assessed in 100 consecutive patients with GCT and in 100 controls with various neoplasms who were matched on sex and age, and who received first-line cisplatin-based chemotherapy during the same period of time at Institut Gustave Roussy, Villejuif, France. Data were subsequently tested on a validation group of 77 GCT patients treated in Lyon, France. A total of 19 patients (19%) (95% confidence interval (CI): 13-28) and six patients (6%) (95% CI: 3-13) had a TEE in the GCT group and the non-GCT control group, respectively (relative risk (RR): 3.4; P<0.01). Three patients from the GCT group died of pulmonary embolism. In multivariate analysis, two factors had independent predictive value for TEE: a high body surface area (>1.9 m2) (RR: 5 (1.8-13.9)) and an elevated serum lactate dehydrogenase (LDH) (RR: 6.4 (2.3-18.2)). Patients with no risk factor (n=26) and those with at least one risk factor (n=71) had a probability of having a TEE of 4% (95% CI: 1-19) and 26% (95% CI: 17-37), respectively. In the GCT validation set, 10 (13%) patients had a TEE; patients with no risk factor and those with at least one risk factor had a probability of having a TEE of 0 and 17% (95% CI: 10-29), respectively. Patients with GCT are at a higher risk for TEE than patients with non-GCT cancer while on cisplatin-based chemotherapy. This risk can be accurately predicted by serum LDH and body surface area. This predictive index may help to study prospectively the impact of thromboprophylaxis in GCT patients.

Adolescent↗
PubMed2005

Sequential high-dose chemotherapy protocol for relapsed poor prognosis germ cell tumors combining two mobilization and cytoreductive treatments followed by three high-dose chemotherapy regimens supported by autologous stem cell transplantation. Results of the phase II multicentric TAXIF trial.

BACKGROUND: High-dose chemotherapy (HD-CT) is able to circumvent platinum resistance of resistant/refractory germ-cell tumors (GCTs), but expectancy of cure remains low. New strategies are needed with new drugs and a sequential approach. MATERIALS AND METHODS: Patients with relapsed poor-prognosis GCTs were scheduled to receive two cycles combining epirubicin and paclitaxel (Taxol) followed by three consecutive HD-CT supported by stem cell transplantation [one course combining cyclophosphamide, 3 g/m(2) + thiotepa, 400 mg/m(2), followed by two ICE regimens (ifosfamide, 10 g/m(2), carboplatin, AUC 20, etoposide, 1500 mg/m(2))]. RESULTS: From March 1998 to September 2001 (median follow-up, 31.8 months), 45 patients (median age, 28 years) were enrolled in this phase II study. Twenty-two patients received the complete course. Twenty-five patients died from progression and five from toxicity. The overall response rate was 37.7%, including an 8.9% complete response rate. The median overall survival was 11.8 months. The 3-year survival and progression-free survival rate was 23.5%. The 'Beyer' prognostic score predicted the outcome after HD-CT. CONCLUSION: Although our results warrant further studies on HD-CT in relapsed poor prognosis GCTs, patients with a Beyer score >2 did not benefit from this approach and should not be enrolled in HD-CT trials. Better selection criteria have to be fulfilled in forthcoming studies.

Adolescent↗
PubMed2004

Detection of HER-2/neu-positive circulating epithelial cells in prostate cancer patients.

HER-2/neu may play a role in prostate carcinogenesis. The aim of this study was to use the expression of HER-2/neu as a molecular marker for the detection of circulating tumour cells (CTCs) in the blood of patients with prostate cancer (PC). Blood samples were collected from 42 patients with PC and nine healthy volunteers. Immunomagnetic beads were used to harvest epithelial cells from peripheral blood mononuclear cells. Total RNA was extracted and reverse transcribed before analysis by real-time PCR with HER-2/neu-specific primers. CTCs were HER-2/neu positive in six out of 11 (54%) patients with metastatic disease and in three out of 31 (9.6%) patients with localised PC (P=0.004). In blood samples from nine healthy volunteers, we detected no expression of HER-2/neu. The present method appears to be minimally invasive, highly sensitive and a specific approach for detecting CTCs in PC. Furthermore, it may help better target HER-2/neu in advanced PC.

Adult↗
PubMed2004

Bilateral germ-cell tumours: 22-year experience at the Institut Gustave Roussy.

The aim of this study was to describe the incidence, clinical and histological characteristics, treatment and long-term follow-up of bilateral germ-cell tumours (BGCT) of the testis in order to determine in what respects they differ significantly from unilateral germ-cell tumours. In all, 31 patients with BGCT had metachronous tumours and 14 had synchronous tumours. Among the metachronous tumours, 61% occurred more than 5 years after the first tumour. The overall incidence of BGCT in patients with testicular germ-cell tumours (TGCT) was 1.9%. The incidence was 3.2% in patients presenting with a seminoma and 1.4 % in patients presenting with a nonseminomatous germ-cell tumour (NSGCT). Patients under 30 years of age at the time of the initial diagnosis had a higher incidence of bilateral tumours compared with older men. The outcome of BGCT was excellent. A high association was found between BGCT, sterility and suspected genetic risk factors for TGCT. These results argue against a systematic contralateral biopsy at diagnosis of first TGCT in all patients, but emphasise the importance of patient education and of the need to better identify patients at risk for a second TGCT. Therapeutic indications for synchronous BGCT, including conservative treatment, need to be better defined.

Adolescent↗
PubMed2004

European consensus on diagnosis and treatment of germ cell cancer: a report of the European Germ Cell Cancer Consensus Group (EGCCCG).

Germ cell tumour is the most frequent malignant tumour type in young men with a 100% rise in the incidence every 20 years. Despite this, the high sensitivity of germ cell tumours to platinum-based chemotherapy, together with radiation and surgical measures, leads to the high cure rate of > or = 99% in early stages and 90%, 75-80% and 50% in advanced disease with 'good', 'intermediate' and 'poor' prognostic criteria (IGCCCG classification), respectively. The high cure rate in patients with limited metastatic disease allows the reduction of overall treatment load, and therefore less acute and long-term toxicity, e.g. organ sparing surgery for specific cases, reduced dose and treatment volume of irradiation or substitution of node dissection by surveillance or adjuvant chemotherapy according to the presence or absence of vascular invasion. Thus, different treatment options according to prognostic factors including histology, stage and patient factors and possibilities of the treating centre as well may be used to define the treatment strategy which is definitively chosen for an individual patient. However, this strategy of reduction of treatment load as well as the treatment itself require very high expertise of the treating physician with careful management and follow-up and thorough cooperation by the patient as well to maintain the high rate for cure. Treatment decisions must be based on the available evidence which has been the basis for this consensus guideline delivering a clear proposal for diagnostic and treatment measures in each stage of gonadal and extragonadal germ cell tumour and individual clinical situations. Since this guideline is based on the highest evidence level available today, a deviation from these proposals should be a rare and justified exception.

Europe↗
PubMed2003

Acute respiratory distress syndrome after chemotherapy for lung metastases from non-seminomatous germ-cell tumors.

GOALS: To describe an acute respiratory distress syndrome (ARDS) occurring after chemotherapy for non-seminomatous germ-cell tumors (NSGCT) with diffuse lung metastases, we conducted a retrospective study in a 15-bed intensive care unit (ICU) in a comprehensive cancer center. PATIENTS AND METHODS: During a 10-year period, 16 consecutive patients with diffuse lung metastases from a NSGCT were admitted to the ICU for respiratory distress and high-risk chemotherapy. MAIN RESULTS: Nine patients developed acute respiratory failure requiring mechanical ventilation (MV) within 3 days of the initiation of chemotherapy, while the respiratory status of the seven other patients improved. The evolution was independent of tumor marker levels and the type of chemotherapy regimen. The SAPS II score did not accurately describe the severity of this population. The only predictor of intubation was the initial PaO2/FiO2 ratio upon admission to the ICU. Six out of seven patients who did not require MV were discharged alive from the hospital, whereas all but one patient requiring MV died. Refractory hypoxemia and ventilator-associated pneumonia were the leading causes of death. CONCLUSIONS: Acute respiratory distress in patients with lung metastases from NSGCT is a rare cause of ARDS. Chemotherapy could be responsible for triggering the respiratory worsening. Patients with severe respiratory insufficiency (PaO2 <70 mmHg on room air) on admission to hospital should be promptly transferred to the ICU for the first chemotherapy course.

Adult↗
PubMed2003

Combination of raltitrexed and oxaliplatin is an active regimen in malignant mesothelioma: results of a phase II study.

PURPOSE: The aim of this open-label phase II study was to evaluate the activity of raltitrexed (Tomudex; AstraZeneca, Cergy, France) and oxaliplatin combination therapy in patients with diffuse malignant pleural mesothelioma. PATIENT AND METHODSs: Fifteen pretreated and 55 chemotherapy-naive patients (median age, 60 years; World Health Organization performance status of < or = 2) were enrolled. Most patients (66%) had advanced disease. Patients received raltitrexed 3 mg/m2 followed by oxaliplatin 130 mg/m2 every 3 weeks. RESULTS: Twenty-four patients (34%) were classified as having a poor prognosis. In the overall study population, 14 patients (20%) had a partial response, and 32 patients (46%) had stable disease. The symptomatic response rates were as follows: shortness of breath, 36%; pain, 30%; activity, 23%; appetite, 21%; and asthenia, 20%. Median time to disease progression was 18 weeks (95% confidence interval [CI], 13 to 22 weeks). In chemotherapy-naive patients, median survival was 31 weeks (95% CI, 23 to 40 weeks) from the start of treatment and 49 weeks (95% CI, 40 to 52 weeks) from diagnosis of mesothelioma. In pretreated patients, median survival was 44 weeks (95% CI, 24 to 40 weeks) from the start of treatment and 226 weeks (95% CI, 63 to 292 weeks) from the diagnosis of mesothelioma. Overall 1-year survival was 26% (95% CI, 15.5% to 36.4%), survival was 22% (95% CI, 10.9% to 33.2%) in chemotherapy-naive patients and 40% (95% CI, 15.2% to 64.8%) in pretreated patients. Hematologic toxicity was mild, and there was no alopecia. The most common adverse events were asthenia, nausea/vomiting, and paraesthesia, and no treatment-related deaths were reported. CONCLUSION: The raltitrexed and oxaliplatin combination is an active outpatient regimen in malignant mesothelioma and has an acceptable tolerability profile.

Adult↗
PubMed2002

Alternating dose-dense chemotherapy in patients with high volume disseminated non-seminomatous germ cell tumours.

Only about half of patients with a poor-prognosis non-seminomatous germ-cell tumours can achieve a cure. The aim of this phase II study was to assess the efficacy and toxicity of a dose-dense alternating chemotherapy regimen in this subset of patients. High volume non-seminomatous germ-cell tumours was defined as follows: at least two sites of non pulmonary metastases, an extragonadal primary tumour, a serum human chorionic gonadotropin level higher than 10 000 mIU x ml(-1), or a alpha-foetoprotein level higher than 2000 mIU ml(-1). Patients who fulfilled these criteria were treated with the so-called BOP-CISCA-POMB-ACE regimen (bleomycin, vincristine, and cisplatin; cisplatin, cyclophosphamide, and doxorubicin; cisplatin, vincristine, methotrexate, and bleomycin; etoposide, dactinomycin, and cyclophosphamide) plus granulocyte colony-stimulating factor. A total of 58 patients were enrolled. Patients were retrospectively classified according to the International Germ-Cell Cancer Consensus Group classification; 38 patients (66%) had poor-prognosis disease and 19 patients (33%) had intermediate-prognosis. Patients received a median of 2.5 courses (range 0.25 to five courses) of the BOP-CISCA-POMB-ACE regimen. Forty-two patients (72.4%) had a complete response to therapy. With a median follow-up time of 31 months, the 3-year progression-free survival rate was 71% (95% confidence interval, 60 to 84%) and the 3-year overall survival rate was 73% (95% confidence interval: 62 to 86%). The 3-year PFS rates were 83% (95% confidence interval: 68 to 100%) in the intermediate-prognosis group and 65% (95% confidence interval: 51 to 82%) in the poor-prognosis group. Early side effects included mainly grade 4 haematologic toxicity (neutropaenia in 79% of patients, thrombocytopaenia in 69%, anaemia in 22%), grade 4 stomatitis (19%), and four early deaths (7% of patients), at least partially related to toxicity. The dose-dense BOP-CISCA-POMB-ACE regimen is highly active in patients with non-seminomatous germ-cell tumours classified as intermediate-prognosis or poor-prognosis according to the International Germ-Cell Cancer Consensus Group. Because outcomes with this regimen compare favourably with outcome after standard therapy, dose-dense chemotherapy should be further investigated in this subset of patients.

Adolescent↗
PubMed2002

A 20% dose reduction of the original CISCA/VB regimen allows better tolerance and similar survival rate in disseminated testicular non-seminomatous germ-cell tumors: final results of a phase III randomized trial.

BACKGROUND: This prospective randomized clinical trial was designed to compare the efficacy of a low-dose regimen of cisplatin, doxorubicin and cyclophosphamide alternated with vinblastine and bleomycin (CISCA/VB) with the original CISCA/VB regimen in patients with disseminated nonseminomatous germ-cell tumors (NSGCT) and a predicted favorable outcome. PATIENTS AND METHODS: One hundred and twenty-five patients with disseminated NSGCT and a predicted favorable outcome according to the M.D. Anderson Cancer Center classification [testicular primary and human chorionic gonadotropin (hCG) serum level <50000 mIU/ml] were randomized to receive the original CISCA/VB regimen (100% dose) or a low-dose CISCA/VB regimen (80% dose). RESULTS: Among the 124 eligible patients, there was no significant difference in the number of patients in the two treatment arms who achieved a complete response to therapy: 53 of 65 patients (82%) on the original CISCA/VB regimen and 53 of 59 patients (90%) on the low-dose CISCA/VB regimen (P = 0.29). Overall, the original CISCA/VB regimen resulted in a significantly higher relative dose intensity (P <0.0001). After a median follow-up of 6.8 years (range 0.37 to 12.94 years), there was no significant difference in disease-free survival (P = 0.87) or in overall survival (P = 0.88) between the two treatment arms. The 5-year overall survival rate was 93.7% [95% confidence interval (CI) 88% to 100%] and 94.1% (95% CI 84% to 100%) in the original CISCA/VB arm and the low-dose CISCA/VB arm, respectively. The 5-year overall survival rate for the entire study population was 98% (95% CI 94% to 100%) and 88% (95% CI 76% to 100%) in the good- and intermediate-prognosis groups, respectively, as defined by the International Germ Cell Consensus Classification Group (IGCCCG). The low-dose CISCA/VB regimen resulted in significantly less neutropenic fever (P <0.001), grade 4 thrombocytopenia (P <0.03) and severe mucositis (P <0.01) than the original CISCA/VB regimen. CONCLUSIONS: CISCA/VB is highly efficient in patients with good or intermediate prognosis NSGCT according to the IGCCCG criteria. Although equivalent antitumor efficacy cannot be claimed, the low-dose CISCA/VB regimen appears to be a better mode of delivery than the original CISCA/VB regimen with respect to toxicity, since survival is comparable.

Adolescent↗
PubMed2001

Incidence of metachronous testicular cancer in patients with extragonadal germ cell tumors.

BACKGROUND: The frequency of subsequent testicular cancer (referred to as metachronous testicular cancer) in men who have had previous testicular cancer is relatively high. The rate of metachronous testicular cancer in men with extragonadal germ cell tumors (EGCTs), however, is largely unknown. We conducted a retrospective study of EGCT patients to determine the incidence, cumulative risk, and specific risk factors for metachronous testicular cancers. METHODS: A standardized questionnaire about patient characteristics, the extent of EGCT disease, any second malignancies, and treatments received was completed for 635 patients with EGCTs identified from the medical records of 11 cancer centers in Europe and the United States from 1975 through 1996. Comparisons with age group-specific data from the Saarland, Germany, population-based cancer registry were used to calculate the standardized incidence ratio (SIR). The Kaplan-Meier method was used to analyze survival data and cumulative risk. All statistical tests were two-sided. RESULTS: Sixteen EGCT patients (4.1%) developed metachronous testicular cancers, with a median time between diagnoses of 60 months (range, 14-102 months). The risk of developing metachronous testicular cancers was statistically significantly increased in patients with EGCTs (observed = 16; expected = 0.26; SIR = 62; 95% confidence interval [CI] = 36 to 99) and in subsets of EGCT patients with mediastinal location (SIR = 31; 95% CI = 8 to 59), retroperitoneal location (SIR = 100; 95% CI = 54 to 172), and nonseminomatous histology (SIR = 75; 95% CI = 43 to 123). The cumulative risk of developing a metachronous testicular cancer 10 years after a diagnosis of EGCT was 10.3% (95% CI = 4.9% to 15.6%) and was higher among patients with nonseminomatous EGCTs (14.3%; 95% CI = 6.7% to 21.9%) and retroperitoneal EGCTs (14.2%; 95% CI = 5.6% to 22.8%) than among patients with seminomatous EGCTs (1.4%; 95% CI = 0.0% to 4.2%) and mediastinal EGCTs (6.2%; 95% CI = 0.1% to 12.2%). CONCLUSIONS: Patients with EGCTs, particularly those with retroperitoneal or nonseminomatous tumors, but also those with primary mediastinal EGCTs, are at an increased risk of metachronous testicular cancer.

Adolescent↗
PubMed2001

Weekly vinorelbine is an effective palliative regimen after failure with anthracyclines and taxanes in metastatic breast carcinoma.

BACKGROUND: Currently, there is no gold standard for the treatment of patients with metastatic breast carcinoma who have experienced failure with anthracyclines and taxanes. A biologic rationale suggests that the mechanism of taxane resistance could be because of an excess of depolymerized tubulin that could enhance sensitivity to vinorelbine. The objective of the study was to assess the tolerance and efficiency of weekly vinorelbine in metastatic breast carcinoma after failure with taxanes. METHODS: Patients with measurable disease, a World Health Organization performance status of less than 3 and a life expectancy longer than 3 months were eligible. Persistent taxane-induced neuropathy higher than Grade 1 was an exclusion criterion. The initial planned dose was 30 mg/m(2)/week on an outpatient basis without granulocyte colony-stimulating factor (G-CSF). Neutrophil and platelet counts of 1.0 and 80 g/L, respectively, were required before each new injection; otherwise vinorelbine was delayed for 7 days with a dose reduction of 5 mg/m(2) at the second episode. The dose also was reduced if Grade 3 or 4 toxicity occurred. If the adverse event persisted or if the delay exceeded 14 days between 2 injections given at a dose of 20 mg/m(2), vinorelbine was definitively discontinued. RESULTS: Between November 1997 and March 1999, 40 patients with a median age of 49 (range, 39-69) were enrolled. All of them had previously received anthracyclines and taxanes. Because of the delays in neutrophil recovery, the median dose intensity did not exceed 22.5 mg/m(2)/week (range, 11.25-30), and the initial planned dose of 30 mg/m(2)/week appeared unfeasible without G-CSF. The starting dose therefore was 25 mg/m(2)/week after the first 6 patients. Neutropenia led to fever in only three patients. Other severe toxicities were Grade 2-3 neuropathy (n = 5), Grade 2-3 ileus (n = 7), Grade 3 anemia (n = 4), and Grade 3 sepsis (n = 1). Objective responses were observed in 10 of 40 patients (25%), 7 of whom had visceral metastases and 4 who were refractory to taxanes (including 2 patients with liver involvement > 50%). The median time to failure was 6 months (range, 4-12) for responding patients. Disease stabilization was achieved in 9 patients (23%) for a median duration of 5 months (range, 4-6). The median survival duration for the whole population was 6 months (range, 2-18+). CONCLUSIONS: Weekly vinorelbine is an active salvage therapy for metastatic breast carcinoma after failure with anthracyclines and taxanes, even in patients with taxane-refractory metastatic breast carcinoma. This confirms that vinorelbine and taxanes are not cross-resistant.

Adult↗
PubMed2001

Germ cell tumors in patients infected by the human immunodeficiency virus.

BACKGROUND: The objective of this study was to assess the natural history of the two disease courses, patient immune system tolerance, and results of therapy in human immunodeficiency virus (HIV)-infected patients with germ cell tumors (GCT). METHODS: From 1985 to 1996, 34 HIV-infected men received a diagnosis of GCT. Their charts were analyzed retrospectively. RESULTS: Sixteen patients had seminomas, and 18 had nonseminomatous GCTs (NSGCT); 71% had International Union Against Cancer (UICC), 1997 Stage I-II GCTs. At the time of chemotherapy, 69%, 6%, and 25% of patients with advanced NSGCT were in the International Germ Cell Consensus Classification (IGCCC) good, intermediate, and poor prognostic group, respectively. All except 1 of the 10 patients with advanced seminomas were in the IGCCC good prognostic group. At diagnosis of GCT, 85% of patients were classified as having asymptomatic HIV infection or only persistent generalized lymphadenectomy. The median CD4 cell count was 325/microL (range, 6-1125). Overall, 26 patients were given chemotherapy, but the planned dose intensity was respected in only 15 (57%) patients. Severe toxic effects included febrile neutropenia in 35% of patients. During chemotherapy, zidovudine, prophylactic granulocyte colony-stimulating factor (G-CSF), and a Pneumocystis carinii prophylaxis were given in 19%, 23%, and 35% of cases, respectively. CD4 cell count decreased in 7 (64%) of 11 patients during chemotherapy. Infradiaphragmatic radiotherapy was given in 10 cases and was clinically well tolerated. At a median follow-up of 27 months (range, 3-150), 50% of patients were alive, and only 18% of patients died of GCT. Two patients developed a non-GCT malignancy while in complete remission, namely, Hodgkin disease and an acute leukemia. CONCLUSIONS: The prognosis of GCT in HIV-infected patients is mostly dictated by the HIV infection. Patients should be treated according to stage and histologic subtype, although dose reduction of chemotherapy might be necessary in approximately half of the patients. Close surveillance of neutrophil and CD4 cells counts, as well as the use of G-CSF and systematic anti-Pneumocystis carinii prophylaxis are recommended during chemotherapy. The use of highly active antiretroviral therapy during chemotherapy for GCT requires a prospective assessment.

Adolescent↗
PubMed2001

Prostate cancer cells induce osteoblast differentiation through a Cbfa1-dependent pathway.

Metastases from prostatic adenocarcinoma (prostate cancer) are characterized by their predilection for bone and typical osteoblastic features. An in vitro model of bone metastases from prostate cancer was developed using a bicompartment coculture system of mouse osteoblasts and human prostate cancer cells. In this model, the bone-derived prostate cancer cell lines MDA PCa 2a and MDA PCa 2b induced a specific and reproducible increase in osteoblast proliferation. Moreover, these cells were able to induce osteoblast differentiation, as assessed by increased alkaline phosphatase activity, Osteocalcin expression, and calcified matrix formation. This osteoblastic reaction was confirmed in vivo by intrafemoral injection of MDA PCa 2b cells into severe combined immunodeficiency disease mice. In contrast, the highly undifferentiated, bone-derived human prostate cancer cell line PC3 did not produce an osteoblastic reaction in vitro and induced osteolytic lesions in vivo. The osteoblast differentiation induced by MDA PCa 2b cells was associated with up-regulation of the osteoblast-specific transcriptor factor Cbfa1. Moreover, treatment of osteoblasts with conditioned medium obtained from MDA PCa 2b cells resulted in up-regulation of Cbfa1 and Osteocalcin expression. In support of the differentiation studies, a microarray analysis showed that primary mouse osteoblasts grown in the presence of MDA PCa 2b cells showed a shift in the pattern of gene expression with an increase in mRNA-encoding Procollagen type I and Osteopontin and a decrease in mRNA-encoding proteins associated with myoblast differentiation, namely myoglobin and myosin light-chain 2. Taken together, these findings suggest that the bone-derived prostate cancer cells MDA PCa 2a and MDA PCa 2b promote differentiation of osteoblast precursors to an osteoblastic phenotype through a Cbfa1-dependent pathway. These results also established that soluble factors produced by prostate cancer cells can induce expression of osteoblast-specific genes. This in vitro model provides a valuable system to isolate molecules secreted by prostate cancer cells that favor osteoblast differentiation. Moreover, it allows to screen for therapeutic agents blocking the osteoblast response to prostate cancer.

Animals↗