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J Albanell

Publications and source records attributed to J Albanell.

At least 37 records · Page 2Linked to original sources
PubMed2000

Gemcitabine/paclitaxel-based three-drug regimens in advanced urothelial cancer.

Transitional cell carcinoma (TCC) of the urothelium is a highly chemosensitive tumour. Combination chemotherapy can provide both palliation and a modest survival advantage in patients with advanced disease. At present, the combination of cisplatin, methotrexate, doxorubicin and vinblastine (M-VAC) is the most widely used for advanced TCC with an overall response rate of 40-72% in phase II, and 35-45% in phase III studies, and a median survival of approximately 12 months. These modest results and the unsuccessful attempts to increase efficacy with dose intensive M-VAC schedules have prompted the identification of new active agents in TCC, such as the taxanes and gemcitabine. The overall response rates for two-drug regimens of cisplatin-paclitaxel, carboplatin-paclitaxel and cisplatin-gemcitabine range from 63 to 72%, 14 to 65% and 42 to 66%, respectively. The overall response rates for platinum-paclitaxel-gemcitabine three-drug regimens range from 58 to 80%. The potential clinical benefit of these new three-drug combinations in the treatment of TCC needs to be tested in future phase III studies.

Adult↗
PubMed2000

Systemic therapy emergencies.

Systemic oncologic therapies can cause multiple emergency situations. There are, however, two unique emergencies directly related to chemotherapy administration: drug extravasation and hypersensitivity reactions (HSRs). Most drugs can cause varying degrees of local tissue injury when extravasated. The medical management of extravasation is based on proper maintenance of the intravenous line, application of local cooling or warming for certain extravasations, and the use of antidotes to prevent the local toxic action of the extravasated drug. Antidotes that appear useful include hyaluronidase (for vinca alkaloids, epipodophyllotoxins, and paclitaxel), sodium thiosulfate (for mechlorethamine and cisplatin), and dimethylsulfoxide (DMSO) (for anthracyclines and mitomycin C). HSRs, another potential adverse effect of chemotherapy administration, are a major concern for therapy with taxanes and with L-asparaginase, and their administration requires the use of premedication to prevent these reactions. Once a HSR has occurred, therapy may be continued by using an analog drug or by the administration of premedication as prophylaxis, in particular if the reaction was minor. On the other hand, it is also pertinent to become acquainted with the emergencies induced by biological agents, taking into consideration their increasing usages. In addition to interferons and interleukin-2 (IL-2), both of which have been in clinical use for several years, cytokine-toxin fusion proteins (DAB3891L-2) and two monoclonal antibodies (rituximab and trastuzumab) were recently approved for cancer therapy. The distinct toxicity profiles of these agents are reviewed.

Antineoplastic Agents↗
PubMed1999

Telomerase activity in germ cell cancers and mature teratomas.

BACKGROUND: An inverse relationship has been reported between the presence of telomerase enzymatic activity and the induction of differentiation in human tumor cell lines. Male germ cell tumors represent an attractive clinical model to assess this relationship further because high telomerase activity is present in normal germ cell progenitors and in embryonal carcinomas that can differentiate into mature teratomas. To investigate how telomerase activity and the differentiation state of germ cell tumors are related, telomerase activities and telomere lengths were measured in benign testicular tissues, germ cell cancers, and mature or immature teratomas. METHODS: By use of a modified telomeric repeat amplification protocol (TRAP) assay, telomerase activity was measured in four specimens of benign testicular tissue, in 27 germ cell cancers, in seven mature teratomas, and in one immature teratoma. Telomere lengths were measured in all specimens by restriction digestion of genomic DNA and Southern blot hybridization analysis. Associations between telomerase activity and tissue histopathology were assessed with two-sided Fisher's exact tests. RESULTS: Telomerase activity was detected in all examined germ cell cancers and in the benign testicular tissue specimens. In marked contrast, telomerase activity was not detected in any mature teratoma (P<.0001). Very long telomeres were detected in some mature teratomas, consistent with telomerase repression as a late event in teratoma formation. The immature teratoma, with malignant transformation, had high telomerase activity. CONCLUSION: Telomerase is active in germ cell cancers and repressed in mature teratomas. The absence of telomerase activity may contribute to the limited proliferative capacity of mature teratomas. These findings support the existence of an inverse relationship between telomerase activity and the differentiation state of clinical germ cell tumors.

Blotting, Southern↗
PubMed1999

Cleavage of the HER2 ectodomain is a pervanadate-activable process that is inhibited by the tissue inhibitor of metalloproteases-1 in breast cancer cells.

HER2/neu, a Mr 185,000 tyrosine kinase receptor that is overexpressed in breast cancer, undergoes proteolytic cleavage of its extracellular domain (ECD). In contrast with other membrane-bound proteins, including growth factor receptors, that are cleaved by a common machinery system, we show that HER2 cleavage is a slow process and is not activated by protein kinase C. Pervanadate, a general inhibitor of protein-tyrosine phosphatases, induces a rapid and potent shedding of HER2 ECD. The shedding of HER2 ECD is inhibited by the broad-spectrum metalloprotease inhibitors EDTA, TAPI-2, and batimastat. The tissue inhibitor of metalloproteases-1; an inhibitor of matrix metalloproteases that does not inhibit cleavage by the general protein kinase C-dependent shedding machinery, also inhibited HER2 ECD shedding, whereas tissue inhibitor of metalloproteases-2 did not. These data suggest that HER2 cleavage is a process regulated by an as-yet-unidentified distinct protease.

Breast Neoplasms↗
PubMed1999

The ErbB receptors as targets for breast cancer therapy.

Breast carcinomas express high levels of ErbB receptors and their ligands, and their overexpression has been associated with a more aggressive clinical behavior. For these reasons therapies directed at these receptors have the potential to be useful anti-cancer treatments. A series of monoclonal antibodies (MAbs)3 directed against the EGF (ErbB1) receptor and the closely related HER2/Neu (ErbB2) receptor are currently under evaluation. These MAbs have shown promising preclinical activity and "chimeric" and "humanized" MAbs have been produced in order to obviate the problem of host immune reactions. These antibodies are currently being tested in clinical trials either alone or in combination with chemotherapeutic agents. Clinical activity with one of these antibodies, trastuzumab, a humanized anti-ErbB2 MAb, has been documented in patients with breast cancer in a series of clinical trials and has recently been approved for the therapy of patients with metastatic ErbB2 overexpressing breast cancer. In addition to antibodies, compounds that inhibit receptor tyrosine kinases have shown significant preclinical activity and are currently being evaluated in the clinic.

Adjuvants, Immunologic↗
PubMed1999

Trastuzumab, a humanized anti-HER2 monoclonal antibody, for the treatment of breast cancer.

The HER2/neu gene encodes a 185 kDa transmembrane receptor (HER2) that belongs to the epidermal growth factor receptor family and has intrinsic tyrosine kinase activity. HER2 is overexpressed in 25-30% of breast cancers and is suggested to have a direct role in the pathogenesis and clinical aggressiveness of HER2 overexpressing tumors. A murine monoclonal antibody, 4D5, directed against the extracellular domain of HER2, is a potent inhibitor of growth of human breast cancer cells overexpressing HER2 in vitro and in xenograft models. To facilitate clinical investigation, 4D5 was humanized by inserting the complementary determining regions of 4D5 into the framework of a consensus human IgG1. The resulting recombinant humanized anti-HER2 MAb, trastuzumab, was found to inhibit the growth of human cancer cells and tumor xenografts overexpressing HER2. Data from phase II trials in women with breast cancer whose tumors overexpress HER2 have shown that trastuzumab has a favorable toxicity profile, is active as a single agent and induces long-lasting objective tumor responses. In combination studies, there was no evidence that trastuzumab enhanced the toxicity of cisplatin and the pharmacokinetic parameters of trastuzumab were unaltered by coadministration of cisplatin. Furthermore, clinical response rates were higher than those reported with either agent alone in a similar patient population. Results of a multicenter, phase III clinical trial of chemotherapy (doxorubicin- or paclitaxel-based) plus trastuzumab as compared to chemotherapy alone in patients with advanced breast cancers overexpressing HER2 showed a significant enhancement in the effects of chemotherapy on time to disease progression, response rates and survival with coadministration of trastuzumab, without increases in overall severe adverse events. Myocardial dysfunction syndrome, similar to that observed with anthracyclines, was reported more commonly with chemotherapy plus trastuzumab. Positive results from clinical studies led to the approval of trastuzumab in the U.S in October 1998 for the treatment of metastatic breast cancer in patients with tumors overexpressing HER2. Since then, the MAb has also been marketed in Switzerland and Canada.

Journal Article↗
PubMed1998

Recombinant humanized anti-HER2 antibody (Herceptin) enhances the antitumor activity of paclitaxel and doxorubicin against HER2/neu overexpressing human breast cancer xenografts.

Recombinant humanized anti-HER2 antibody, rhuMAb HER2, inhibits the growth of breast cancer cells overexpressing HER2 and has clinical activity. We explored in preclinical models its capacity to enhance the tumoricidal effects of paclitaxel and doxorubicin. In cultures of naturally HER2-overexpressing cancer cells, rhuMAb HER2 inhibited growth and enhanced the cytotoxic effects of paclitaxel. Treatment of well established BT-474 breast cancer xenografts overexpressing HER2 in athymic mice with rhuMAb HER2 resulted in a dose-dependent antitumor activity. In combination studies, treatment with paclitaxel and rhuMAb HER2 or doxorubicin and rhuMAb HER2 resulted in greater inhibition of growth than that observed with any agent alone. The combination of paclitaxel and rhuMAb HER2 resulted in the highest tumor growth inhibition and had a significantly superior complete tumor regression rate when compared with either paclitaxel or rhuMAb HER2 alone. Clinical trials that are built on these results are under way.

Animals↗
PubMed1998

Cyclophosphamide, methotrexate, and chronic oral tegafur modulated by folinic acid in the treatment of patients with advanced breast carcinoma.

BACKGROUND: Chronic oral tegafur (a 5-fluorouracil prodrug) modulated by folinic acid has antitumor activity in patients with metastatic breast carcinoma resistant to 5-fluorouracil or doxorubicin-based regimens. In this study, bolus 5-fluorouracil was substituted with chronic oral tegafur and folinic acid in a cyclophosphamide, methotrexate, and 5-fluorouracil-based regimen to study the activity of this novel regimen in patients with advanced breast carcinoma. METHODS: This study was comprised of patients with advanced breast carcinoma and measurable or evaluable disease. Patients with prior chemotherapy were eligible. The regimen was comprised of cyclophosphamide, 600 mg/m2, and methotrexate, 40 mg/m2, both given intravenously on Day 1, and tegafur, 750 mg/m2, with folinic acid, 45 mg/day, both given orally in 3 daily fractions on Days 2-14, every 3 weeks. RESULTS: Forty-seven patients were included, 44 of whom were fully assessable. Three patients (7%) achieved a complete remission and 17 (38.6%) achieved a partial remission, for an objective response rate of 45.5% (95% confidence interval, 29-59%). The median duration of response was 11 months. In previously untreated patients the response rate was 54.5%. In patients previously treated with anthracycline or 5-fluorouracil-based regimens the response rates were 41% and 39%, respectively. Sixteen patients (36.4%) had disease stabilization. The median overall time to progression was 10 months. Toxicities usually were mild and were comprised of leukocytopenia, mucositis, emesis, and diarrhea. CONCLUSIONS: Chronic oral tegafur and folinic acid combined with intravenous cyclophosphamide and methotrexate at the dose and schedule used in the current study has significant antitumor activity both as first-line chemotherapy as well as in other patients with advanced breast carcinoma who had prior chemotherapy. This regimen is well tolerated, with gastrointestinal toxicity being the most frequent and dose-limiting toxicity.

Administration, Oral↗
PubMed1998

Dose-dense therapy with weekly 1-hour paclitaxel infusions in the treatment of metastatic breast cancer.

PURPOSE: To evaluate the efficacy and toxicity of paclitaxel administered as a 1-hour infusion on weekly basis, without interruption, to patients with metastatic breast cancer who had received prior therapy. PATIENTS AND METHODS: Thirty patients with metastatic breast cancer received sustained weekly paclitaxel therapy at an initial dose of 100 mg/m2 until disease progression. Prior therapy included adjuvant only (n=17), metastatic only (n=7), or both (n=6). Eighteen patients had received prior anthracycline therapy, 12 of whom had demonstrated progression of disease within 12 months of it. All patients were assessable for efficacy; 29 patients were assessable for toxicity. Pharmacokinetic studies of paclitaxel were also performed. RESULTS: A total of 469 weekly paclitaxel infusions were administered to 30 patients (median, 14 infusions/patient). The median delivered dose-intensity was 91 mg/m2/wk (range, 80 to 108). The overall response rate was 53% (95% confidence interval [CI], 34% to 72%), with 10% complete responses (CRs) and 43% partial responses (PRs). Median response duration was 7.5 months (range, 2 to 11+). Responses were observed in nine of 18 (50%) patients with prior anthracycline therapy, including six of 12 (50%) with disease progression on anthracycline within 1 year (three of four within 6 months). Therapy was well tolerated and remarkable for a lack of overall and cumulative myelosuppression. Grade 3/4 neutropenia occurred in four patients; febrile neutropenia was not observed. Peripheral neuropathy prohibited dose escalation above 100 mg/m2, and grade 3 neuropathy was observed in two of 21 patients at < or = 100 mg/m2. CONCLUSION: Weekly paclitaxel therapy is active and well tolerated in patients with metastatic breast cancer. Weekly therapy should be considered as a current clinical option for these patients and should be incorporated into future comparative clinical trials.

Adult↗
PubMed1997

Carboplatin-based versus cisplatin-based chemotherapy in the treatment of surgically incurable advanced bladder carcinoma.

BACKGROUND: The carboplatin-based chemotherapeutic regimen M-CAVI (methotrexate, carboplatin, and vinblastine) is active against bladder carcinoma and can be administered to patients who are ineligible to receive cisplatin or doxorubicin. The authors designed a randomized study to evaluate whether M-CAVI offers a therapeutic advantage over the cisplatin-based regimen M-VAC (methotrexate, vinblastine, doxorubicin, and cisplatin) in the treatment of patients with surgically incurable advanced bladder carcinoma. METHODS: Patients with surgically incurable advanced bladder carcinoma were enrolled on a randomized trial comparing M-CAVI, which consists of carboplatin (300 mg/m2 on Day 2, adjusted using Calvert's formula for an area under the curve of 5), methotrexate (30 mg/m2 on Days 1, 15, and 22), and vinblastine (3 mg/m2 on Days 2, 15, and 22) administered every 28 days, versus standard M-VAC. The eligibility criteria included histologically proven bladder carcinoma, surgically incurable disease, and no prior chemotherapy. Patients were treated until disease progression or unacceptable toxicity occurred. RESULTS: From January 1989 to January 1994, 47 assessable patients were included. Seventeen patients had lymph node disease and 30 had distant metastatic disease. Twenty-three patients were randomized to receive M-CAVI and 24 to receive M-VAC. Patient characteristics in the two groups were similar. Overall response rates were 39% (95% confidence interval [CI], 20-62%) for M-CAVI and 52% (95% CI, 30-73%) for M-VAC (P = 0.3), with 3 complete responses observed among patients treated with M-VAC and none among those in the M-CAVI group. M-VAC was associated with more gastrointestinal toxicity, stomatitis, alopecia, and Grade 4 neutropenia than M-CAVI. One toxicity-related death occurred in the M-VAC group. There was a statistically significant difference in median disease-related survival time favoring M-VAC (16 months; range, 6 to 22+) versus M-CAVI (9 months; range, 6 to 14+) (P = 0.03). CONCLUSIONS: M-CAVI is less toxic but less active than M-VAC in the treatment of patients with advanced bladder carcinoma. Carboplatin-based regimens in which carboplatin is administered at the dose range used in the current study should be reserved for patients who cannot tolerate cisplatin treatment. Further research is required to assess the impact of high dose carboplatin in the treatment of this disease.

Adult↗
PubMed1997

High telomerase activity in primary lung cancers: association with increased cell proliferation rates and advanced pathologic stage.

BACKGROUND: Telomerase enzyme activity is not detected in most normal cells, a phenomenon believed to be associated with limitations on cellular proliferation. Since this activity is detected in nearly all human tumors, including non-small-cell lung cancers, it has been suggested that telomerase activation may be coupled to acquisition of the malignant phenotype. In this study, we determined whether telomerase activity was associated with tumor pathologic stage, tumor cell proliferation rates, and clinical outcome in a cohort of patients with resected non-small-cell lung cancer for whom long-term follow-up was available. METHODS: Primary tumor specimens from 99 patients treated with surgery alone and six patients treated with surgery after chemotherapy were analyzed. Telomerase activity was measured by means of a modified Telomeric Repeat Amplification Protocol (TRAP) assay. Southern blot analysis of terminal restriction fragments was used to evaluate telomere length. Immunohistochemical analysis of Ki-67, a proliferation-associated nuclear antigen, was used to assess tumor cell proliferation. RESULTS: Telomerase activity was detected in 84 of the 99 tumors treated with surgery alone; this activity was not detected in specimens of adjacent, benign lung tissue. Telomerase was detected in only three of six tumors resected after chemotherapy. For the surgery-alone group, statistically significant positive associations were found between the level of telomerase activity and tumor stage, lymph node metastasis, pathologic TNM (tumor-node-metastasis) stage, and Ki-67 immunostaining; a statistically significant inverse association was found between telomerase activity and patient age. No statistically significant differences in telomere length were found in relation telomerase activity or pathologic stage. Telomerase activity was not found to be associated with clinical outcome in a multivariate Cox proportional hazards analysis adjusted for tumor stage and lymph node status. CONCLUSIONS: High telomerase activity is detected frequently in primary non-small-cell lung cancers that exhibit high tumor cell proliferation rates and advanced pathologic stage.

Adenocarcinoma↗
PubMed1997

Downregulation of telomerase activity in HL60 cells by differentiating agents is accompanied by increased expression of telomerase-associated protein.

Telomerase activity provides a mechanism for the unlimited division potential of neoplastic cells. Induced differentiation of these cells was found to be associated with repression of telomerase activity irrespective of the inducing agent. We have employed a series of sublines of human promyelocytic leukemia line HL60 with differing degrees of resistance to differentiation to determine how tightly the expression of the differentiated phenotype is coupled to the downregulation of telomerase activity and to the expression of the recently identified telomerase-associated protein 1 (TP1). As expected, in the 1,25D3-dihydroxyvitamin D3 (1,25D3)-resistant subclones (20A-100A cells), telomerase activity was not significantly downregulated by 1,25D3 and, in most cases, by all-trans retinoic acid (atRA), to which these cells were cross-resistant, but telomerase activity was repressed by dimethylsulfoxide (DMSO) and phorbol-12-myristate-13-acetate (TPA), to which the sublines were in general sensitive. However, there were exceptions; in some instances telomerase activity was repressed in the absence of the expression of markers of differentiation. Also, there was an inverse relationship between telomerase activity and the cellular levels of TP1 transcripts. We conclude that in HL60 cells downregulation of telomerase is loosely associated with upregulation of differentiation markers and with other cellular changes which include an upregulation of TP1.

Calcitriol↗
PubMed1997

Telomerase regulation, cell cycle, and telomere stability in primitive hematopoietic cells.

Low levels of telomerase activity have recently been detected in human primitive hematopoietic cells, however, blood cells exhibit telomere shortening on cell proliferation. This challenging observation led us to study telomerase regulation and telomere length in human hematopoietic progenitor cells from fetal liver (FL), cord blood (CB), peripheral blood (PB), and bone marrow (BM). We found telomerase activity in CD34+/CD38+ cells exceeding levels in CD34+/CD38-, CD34- , and mononuclear cells (P < .05). Baseline telomerase activity was highest in BM (n = 5) CD34+ cells, followed by PB (n = 20), CB (n = 11), and FL (n = 1). Within 48 hours to 72 hours of in vitro culture of CD34+ cells in the presence of cytokines (KL, interleukin-3 [IL-3], IL-6, erythropoietin, granulocyte colony-stimulating factor), telomerase activity was upregulated, peaked after 1 week of culture, and decreased to baseline levels or below detection after 3 to 4 weeks. Stimulation of CD34+ cells with single cytokines resulted in no or minor telomerase upregulation, whereas cytokine combinations resulted in a significant telomerase increase (P < .001). There was a correlation between telomerase activity, cell cycle status by BrdU incorporation, and induction of phosphorylated retinoblastoma protein, CDC2, CDK2, cyclin D1, and cyclin A, but not cyclin E and B1 after 72 hours with multiple (but not single) cytokines. In nonexpanding CD34+ cells, telomerase was low or undetectable. Secondary CD34+ cells showed a reduced ability to upregulate telomerase activity. Antiproliferative cytokines such as transforming growth factor-beta1 and high concentrations of all-trans-retinoic acid in cytokine-supported CD34+ cultures downmodulated telomerase activity. Average telomere lengths were 10.4 kbp, 7.4 kbp, and 7.6 kbp in CB, PB, and BM CD34+ cells, respectively. In ex vivo expansion cultures, an average telomeric DNA loss of 1 to 2 kbp over 4 weeks was observed. However, the rate of base pair loss per population doubling was significantly lower during the first 2 weeks, when telomerase was upregulated, than during weeks 3 and 4 of culture. In summary, telomerase is upregulated in response to cytokine-induced proliferation and cell cycle activation in primitive hematopoietic cells. Telomerase is downregulated between weeks 3 and 4 of ex vivo expansion culture linked with decreased proliferation and greater expansion of more mature cell subsets. Our data suggest that telomerase activity in hematopoietic cells reduces, but does not prevent, telomere shortening on proliferation.

Antigens, CD34↗
PubMed1997

Feasibility trial of high-dose 7-day continuous-infusion ifosfamide given on an outpatient basis.

High-dose ifosfamide (HD-IFX) has shown significant antitumor activity in advanced sarcoma and breast carcinoma. The use of uroprotective agents and the availability of ambulatory continuous-infusion pumps has allowed dose escalation in the administration of ifosfamide (IFX) on an outpatient schedule. We report the results of a phase II trial of IFX given at high doses to heavily pretreated patients. IFX was infused at 2 g/m2 per day for a total of 7 days through a central venous access, with cycles being repeated every 21 days. Mesna was given concomitantly at equimolar doses. No hematopoietic support was used. A total of 27 heavily pretreated patients whose disease had progressed during conventional-dose chemotherapy were included (14 sarcomas, 10 breast carcinomas, and 3 bladder carcinomas). Reversible neutropenia and gastrointestinal toxicity were the most frequently encountered toxicities. Only two patients developed transient renal failure, and two others developed central nervous system toxicity. No treatment-related death was observed. Of 22 patients who were evaluable for response, 6 (27%) showed an objective response (OR), all ORs being partial responses (PRs) with a median duration of 6 months, and 12 patients had stable disease (SD; 55%) with a median duration of 3.5 months. The median overall survival (OS) was 6 months. Three patients underwent high-dose chemotherapy after showing a response to our IFX schedule. We conclude that continuous-infusion IFX given in an outpatient setting is a feasible and active regimen that produces, a manageable toxicity profile in heavily pretreated breast cancer and sarcoma patients. Early institution of this schedule in less advanced stages could improve the results obtained.

Antineoplastic Agents, Alkylating↗
PubMed1997

Common defects of different retinoic acid resistant promyelocytic leukemia cells are persistent telomerase activity and nuclear body disorganization.

The acute promyelocytic leukemia (APL) t(15;17) rearrangement fuses the promyelocytic leukemia (PML) gene to the retinoic acid receptor-alpha (RAR alpha). There is expression of the chimeric transcript, PML/RAR alpha, in these APL cells. These clinical APL cases respond to the differentiation agent all-trans retinoic acid (ATRA) with complete but not durable remissions because ATRA resistance develops. The NB4 APL cell line expresses PML/RAR alpha and responds to the growth inhibitory and differentiation-inducing signals of ATRA. To identify mechanisms responsible for ATRA resistance in APL, ATRA-resistant NB4 cell lines were derived from parental NB4 cells using different strategies. These lines were resistant to the growth inhibition and differentiation effects of ATRA. ATRA-resistant cells were isolated as a de novo resistant line from parental NB4 cells (NB4-R1), following chemical mutagenization and selection in ATRA (NB4-R2), or after chronic selection in ATRA (NB4-R3). Common defects linked to this ATRA resistance were found. When cultured in ATRA, these resistant cells still express PML, RAR alpha, and PML/RAR alpha proteins. Sequence abnormalities were not detected in the RAR alpha DNA binding domains cloned from a representative RA-resistant NB4 line. In ATRA-sensitive but not ATRA-resistant NB4 cells, ATRA down-regulated retinoid X receptor-alpha (RXR alpha) expression, a known marker of ATRA response in parental NB4 cells. Notably, engineered overexpression of RXR alpha in ATRA-sensitive NB4 cells did not block ATRA-mediated growth suppression. ATRA treatment of these resistant NB4 lines did not signal a decline in telomerase activity or reorganization of PML-associated nuclear bodies, but both events occurred in ATRA-sensitive NB4 cells. These ATRA-resistant NB4 lines are not fully differentiation-defective, since monocytic maturation was induced following treatment with phorbol 12-myristate 13-acetate (PMA) and 1,25 dihydroxy vitamin D3 (vitamin D3). Notably, induced monocytic differentiation of these distinct ATRA-resistant APL lines markedly repressed telomerase activity. Thus, this study suggests that persistent telomerase activity and nuclear body disorganization are linked to ATRA resistance in APL.

Antineoplastic Agents↗
PubMed1997

Frequent dose delays and growth factor requirements with the sequential doxorubicin-CMF schedule.

Doxorubicin for four cycles plus cyclophosphamide, methotrexate and 5-fluorouracil (CMF) for eight cycles is an effective adjuvant regimen for breast cancer patients with more than three involved axillary lymph nodes. We reviewed the incidence of dose delays and growth factor requirements when this regimen is administered to patients receiving concurrent irradiation. Thirty-six patients with more than three involved axillary lymph nodes were treated with the sequential regimen doxorubicin-CMF and irradiation. Patients with two or more dose delays received G-CSF treatment. Seventy-five percent of the patients required dose delays for day-22 neutropenia, and growth factors were needed for half of the patients in order to maintain a received dose intensity of 0.940. The first delayed cycle occurred in 74% of the patients while receiving concomitant chemoradiotherapy. Frequent dose delays were required when the sequential regimen doxorubicin-CMF was administered along with radiotherapy. Growth factors are needed to maintain dose intensity similar to that achieved in the original trial.

Adult↗
PubMed1997

Relative contribution of normal and neoplastic cells determines telomerase activity and telomere length in primary cancers of the prostate, colon, and sarcoma.

Telomerase and telomere length are increasingly investigated as potential diagnostic and prognostic markers in human tumors. Among other factors, telomerase and telomere length may be influenced by the degree of tumor cell content in tumor specimens. We studied telomerase activity and telomere length with concomitant integration of histopathological data to determine whether both were influenced by the amount of tumor cells. We measured telomerase in 153 specimens: in 51 solid tumor blocks; in 51 cryostat sections; and in 51 adjacent normal tissues from patients with sarcoma (n = 10) and colorectal (n = 11) and prostate cancer (n = 30) using the sensitive and rapid detection telomeric repeat amplification protocol assay. Telomere length was determined by telomere restriction fragment Southern blot analysis. From cryostat sections, tumor cell infiltration was assessed. Telomerase activity was detected in all colorectal tumors and sarcomas, as expected. In primary prostate cancer, however, telomerase activity was less frequently observed (14 of 30, 47%). Moreover, a decreased intensity compared to colon cancer and sarcoma was evident (P < 0.001). The median tumor cell infiltration was significantly higher in sarcoma (65%) and colon (30%) compared to prostate cancer (5%; P < 0.001). There was a positive correlation between tumor cell infiltration and telomerase activity (r = 0.89; P < 0.001). Telomere restriction fragments in tumors were shorter compared to the normal tissues with peak differences in colon, sarcoma, and prostate of 1.8, 2.8, and 1 kilobase pairs, respectively (P < 0.002). Our data suggest the presence of a positive correlation between the degree of tumor cell content in human solid tumors and the level of telomerase activity detected. We demonstrated that the amount of tumor cells also affects telomere restriction fragment analysis. Therefore, with the predominance of normal cells in tumor specimens, telomerase activity measured may not reflect the malignant phenotype, and telomere loss may be underestimated. This phenomenon was most evident in prostate cancer. Our results will have implications for the future when telomerase activity and telomere lengths may be used for early screening, diagnosis, and prognosis determinations and when telomerase inhibitors are applied to clinical practice.

Adenocarcinoma↗