Biomedical subjects

J Baselga

Publications and source records attributed to J Baselga.

At least 91 records · Page 5Linked to original sources

PubMed1996

Expression of the fructose transporter GLUT5 in human breast cancer.

The primary metabolic characteristic of malignant cells is an increased uptake of glucose and its anaerobic metabolism. We studied the expression and function of the glucose transporters in human breast cancer cell lines and analyzed their expression in normal and neoplastic primary human breast tissue. Hexose uptake assays and immunoblotting experiments revealed that the breast carcinoma cell lines MCF-7 and MDA-468 express the glucose transporters GLUT1 and GLUT2, isoforms expressed in both normal and neoplastic breast tissue. We also found that the breast cancer cell lines transport fructose and express the fructose transporter GLUT5. Immunolocalization studies revealed that GLUT5 is highly expressed in vivo in human breast cancer but is absent in normal human breast tissue. These findings indicate that human breast cancer cells have a specialized capacity to transport fructose, a metabolic substrate believed to be used by few human tissues. Identification of a high-affinity fructose transporter on human breast cancer cells opens opportunities to develop novel strategies for early diagnosis and treatment of breast cancer.

Breast↗

PubMed1996

Autocrine regulation of membrane transforming growth factor-alpha cleavage.

Transforming growth factor alpha (TGF-alpha) is biosynthesized as a membrane-bound precursor protein, pro-TGF-alpha, that undergoes sequential endoproteolytic cleavages to release a soluble form of the factor. In the present study, we have analyzed the biosynthesis and regulation of TGF-alpha production in human tumor-derived cell lines that endogenously express pro-TGF-alpha and the epidermal growth factor (EGF) receptor. These cells biosynthesized membrane-anchored forms of the TGF-alpha that accumulated on the cell surface. Membrane-bound pro-TGF-alpha interacted with the EGF receptor, and complexes of receptor and pro-TGF-alpha contained tyrosine-phosphorylated receptor. Activation of the EGF receptor by soluble EGF or TGF-alpha had a dual effect on TGF-alpha production: an increase in pro-TGF-alpha mRNA levels and an increase in pro-TGF-alpha cleavage. These effects were largely prevented by preincubation with an anti-EGF receptor monoclonal antibody that blocked ligand binding. Growth factor autoinduction of cleavage could be stimulated by several second messenger pathways that are activated by the EGF receptor, including protein kinase C and intracellular calcium, and by other alternative mechanisms. EGF-stimulated cleavage of pro-TGF-alpha could be partially blocked by inhibition of these second messenger pathways. These results suggest that juxtacrine stimulation takes place in human tumor cells that coexpress both the EGF receptor and membrane-anchored TGF-alpha and that TGF-alpha is able to induce its own endoproteolytic cleavage by activating the EGF receptor.

Animals↗

PubMed1996

Phase II and pharmacologic study of docetaxel as initial chemotherapy for metastatic breast cancer.

PURPOSE: Because docetaxel (Taxotere, RP 56976; Rhone-Poulenc Rorer, Antony, France) appeared to be active against breast cancer in phase I trials, we performed this phase II study. PATIENTS AND METHODS: Thirty-seven patients with measurable disease were enrolled. Only prior hormone therapy was allowed, as was adjuvant chemotherapy completed > or = 12 months earlier. Docetaxel 100 mg/m2 was administered over 1 hour every 21 days. Diphenhydramine hydrochloride and/or corticosteroid premedication was added after hypersensitivity-like reactions (HSRs) were seen in two of the first six patients. Pharmacokinetic studies were performed during cycle 1 for correlation with toxicity. RESULTS: Thirty-seven patients were assessable. Nineteen (51%) required dose reductions, usually for neutropenic fever. The median nadir WBC count was 1.4 x 10(3)/microL. HSRs were noted in 20 patients (54%). At a median cumulative dose of 297 mg/m2 (range, 99.6 to 424.5 mg/m2), 30 patients (81%) developed fluid retention, for which 11 (30%) subsequently stopped treatment. The first-cycle plasma area under the concentration-time curve (AUC) did not correlate with toxicity, although an ineligible patient with hepatic metastases (pretreatment bilirubin level 1.8 mg/dL) had an elevated AUC and died of toxicity. Responses were seen at all sites. On an intent-to-treat basis, there were two (5%) complete responses (CRs) and 18 (49%) partial responses (PRs). The overall response proportion (CRs plus PRs) was 54% (95% confidence interval, 37% to 71%). The median time to response was 12 weeks (range, 3 to 15) and the median duration was 26 weeks (range, 10 to 58+). CONCLUSION: Docetaxel is active for metastatic breast cancer. Neutropenia and fluid retention are dose-limiting. The AUC did not predict toxicity, but caution is warranted when treating patients with liver dysfunction. An understanding of the pathophysiology of the fluid retention may facilitate prevention. Frequent HSR may warrant prophylactic premedication.

Adult↗

PubMed1996

Phase II study of weekly intravenous recombinant humanized anti-p185HER2 monoclonal antibody in patients with HER2/neu-overexpressing metastatic breast cancer.

PURPOSE: Breast cancer frequently overexpresses the product of the HER2 proto-oncogene, a 185-kd growth factor receptor (p185HER2). The recombinant humanized monoclonal antibody (rhuMAb) HER2 has high affinity for p185HER2 and inhibits the growth of breast cancer cells that overexpress HER2. We evaluated the efficacy and toxicity of weekly intravenous administration of rhuMAb HER2 in patients with HER2-overexpressing metastatic breast cancer. PATIENTS AND METHODS: We treated 46 patients with metastatic breast carcinomas that overexpressed HER2. Patients received a loading dose of 250 mg of intravenous rhuMAb HER2, then 10 weekly doses of 100 mg each. Patients with no disease progression at the completion of this treatment period were offered a maintenance phase of 100 mg/wk. RESULTS: Study patients had extensive metastatic disease, and most had received extensive prior anticancer therapy. Adequate pharmacokinetic levels of rhuMAb HER2 were obtained in 90% of the patients. Toxicity was minimal and no antibodies against rhuMAb HER2 were detected in any patients. Objective responses were seen in five of 43 assessable patients, and included one complete remission and four partial remissions (overall response rate, 11.6%; 95% confidence interval, 4.36 to 25.9). Responses were observed in liver, mediastinum, lymph nodes, and chest wall lesions. Minor responses, seen in two patients, and stable disease, which occurred in 14 patients, lasted for a median of 5.1 months. CONCLUSION: rhuMAb HER2 is well tolerated and clinically active in patients with HER2-overexpressing metastatic breast cancers that had received extensive prior therapy. This is evidence that targeting growth factor receptors can cause regression of human cancer and justifies further evaluation of this agent.

Adult↗

PubMed1996

Five-day course of granulocyte colony-stimulating factor in patients with prolonged neutropenia after adjuvant chemotherapy for breast cancer is a safe and cost-effective schedule to maintain dose-intensity.

PURPOSE: To analyze the safety and efficacy of a short course of granulocyte colony-stimulating factor (G-CSF) to maintain dose-intensity of subsequent cycles of chemotherapy after a prior episode of prolonged neutropenia, without febrile complications, in patients receiving adjuvant treatment for breast cancer. PATIENTS AND METHODS: Thirty-two patients undergoing adjuvant cyclophosphamide, methotrexate, and fluorouracil (CMF) or doxorubicin-CMF for stages I to II breast cancer were included after having chemotherapy delays due to neutropenia (absolute neutrophil count [ANC] < 1.5 x 10(9)/L) on day 22. G-CSF was administered subcutaneously on days 15 to 19 of each subsequent cycle. RESULTS: None of the patients included in this study had to be admitted to the hospital for fever and neutropenia. The median percentage of the projected dose-intensity for CMF or doxorubicin-CMF on an intent-to-treat basis was 0.994, which was significantly higher than the delivered dose-intensity before the start of G-CSF treatment (P < .0001). Patients who received concomitant G-CSF and radiotherapy achieved a similar dose-intensity as patients who did not undergo radiotherapy. Seven patients discontinued G-CSF treatment due to musculoskeletal pain. These patients had more subsequent cycle delays because of day 22 neutropenia than the 25 patients who followed the G-CSF schedule (P = .0028). CONCLUSION: A 5-day course of G-CSF in patients with prior chemotherapy delays due to prolonged neutropenia seems to be a safe and cost-effective schedule to maintain CMF or doxorubicin-CMF dose-intensity in the adjuvant treatment of breast cancer.

Adult↗

PubMed1996

Ninety-six-hour paclitaxel infusion after progression during short taxane exposure: a phase II pharmacokinetic and pharmacodynamic study in metastatic breast cancer.

PURPOSE: A phase II trial of paclitaxel infused over 96 hours in patients with metastatic breast cancer with demonstrated disease progression (PD) during short-infusion taxane treatment was performed to evaluate schedule-dependent activity with prolonged drug exposure. The tolerability of this strategy and its pharmacokinetic profile and pharmacodynamic correlates were also investigated. PATIENTS AND METHODS: Paclitaxel was administered to 26 patients with metastatic breast cancer at 120 to 140 mg/m2 intravenously over 96 hours. Twenty-three patients had demonstrated PD while receiving prior 3-hour paclitaxel, two during 1-hour docetaxel, and one during infusions of docetaxel and then paclitaxel. Twenty-one patients (81%) had no prior response to the short taxane infusion (primary resistance) and five (19%) had prior partial responses (PRs) of brief duration before PD (secondary resistance). Plasma paclitaxel concentrations were assessed at 24, 48, 72, and 96 hours. RESULTS: After delivery of 195 cycles, seven of 26 assessable patients (26.9%; 95% confidence interval, 11.6% to 47.8%) had major objective responses, with a median response duration of 6 months (range, 1 to 13). The predominant toxicities were neutropenia (76% grade > or = 3) and stomatitis (15% grade > or = 3). Despite omission of premedications, no significant hypersensitivity reactions occurred. The median steady-state paclitaxel concentration (Css) in 23 assessable patients was 0.047 mumol/L (range, .023 to .176). Patients who experienced grade 4 neutropenia had significantly decreased paclitaxel clearance and higher Css than those with grade 1 to 3 neutropenia (P < .05). Pretreatment elevation of hepatic transaminases was associated with delayed clearance (P < .01) and increased myelo-suppression and mucosal toxicity. CONCLUSION: Paclitaxel demonstrates activity against metastatic breast cancer when administered over 96 hours to patients with disease that recently had progressed during short taxane exposure. Delayed paclitaxel clearance and consequent increased toxicity occurred in patients with hepatic dysfunction. The activity observed supports preclinical data that suggest variability in efficacy and resistance patterns to paclitaxel based on duration of exposure.

Adult↗

PubMed1996

Sequential adjuvant therapy: the Memorial Sloan-Kettering Cancer Center experience.

Adjuvant chemotherapy has a real but modest impact on the disease-free and overall survival of patients with breast cancer. Recent attempts to improve its effectiveness have focused on dose intensity and new agents. Sequential therapy maximized dose intensity while limiting overlapping toxicity. Sequential therapy using doxorubicin followed by cyclophosphamide/methotrexate/5-fluorouracil (CMF) has been found superior in patients with high-risk resectable breast cancer. The novel chemotherapy agent paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) is now known to be highly active in advanced breast cancer and appears to be clinically non-cross-resistant with doxorubicin. Therefore, this drug is being studied as a component of the next generation of adjuvant chemotherapy regimens. The most appropriate way to incorporate paclitaxel has not yet been defined, but its concurrent administration with other agents has, in some cases, been troublesome. Based on the demonstrated advantage of the sequential plan for doxorubicin and CMF, we conducted a series of pilot trials testing sequential high-dose therapy. Initially, we studied multiple cycles of doxorubicin followed by cyclophosphamide; we later added paclitaxel to this regimen. These phase II studies demonstrate the feasibility of sequential therapy with doxorubicin, paclitaxel, and cyclophosphamide, and early disease-free survival results are promising. Cooperative group projects are under way or planned to further define the activity of these regimens.

Antineoplastic Agents, Phytogenic↗

PubMed1995

Paclitaxel as second and subsequent therapy for metastatic breast cancer: activity independent of prior anthracycline response.

PURPOSE: Two phase II clinical trials were performed to determine efficacy and tolerability of paclitaxel (Taxol; Bristol-Myers Squibb Co, Wallingford, CT) and granulocyte colony-stimulating factor ([G-CSF] Neupogen; Amgen, Inc, Thousand Oaks, CA) as second or subsequent therapy for metastatic breast cancer. PATIENTS AND METHODS: Paclitaxel plus G-CSF was administered as a second stage IV regimen to 25 patients with metastatic breast cancer at a dose of 250 mg/m2 intravenously over 24 hours. Fifty-two patients received paclitoxel plus G-CSF at 200 mg/m2 as a third or subsequent regimen (no restriction on number of prior regimens or on prior high-dose chemotherapy). All patients had received prior anthracycline treatment, and ultimately had progressive bidimensionally measurable disease. RESULTS: Twenty-five of 76 patients (32.8%) had a major objective response (95% confidence interval [CI], 14% to 37%). The median duration of response was 7 months (range, 1 to 20+). Responses were as likely in patients with disease demonstrated to be unresponsive to anthracycline, ie, de novo resistance (11 of 37, or 30%) as in those with disease that once exhibited anthracycline sensitivity, ie, acquired resistance, (10 of 31, or 32%). G-CSF administration was associated with febrile neutropenic episodes in 36 of 402 cycles (9%) in 16 of 76 patients (21%). CONCLUSION: Paclitaxel's clinically significant activity against metastatic breast cancer extends to patients with many prior chemotherapy regimens. The lack of impact of prior doxorubicin therapy on the likelihood of subsequent response to paclitaxel suggests an important role for this agent in the treatment of refractory metastatic breast cancer.

Adult↗

PubMed1995

Memorial Sloan-Kettering Cancer Center experience with paclitaxel in the treatment of breast cancer.

Paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) is the most important new cytotoxic agent to be introduced for the management of breast cancer in many years. During this decade, investigators at Memorial Sloan-Kettering Cancer Center have conducted multiple clinical and laboratory investigations aimed at optimally integrating this agent into therapeutic strategies for breast cancer. These studies address both single-agent and combination regimens in the metastatic and adjuvant settings. This report will review previous results, but focus on active studies and future avenues of research.

Antineoplastic Agents, Phytogenic↗

PubMed1995

Sequential adjuvant therapy with doxorubicin/paclitaxel/cyclophosphamide for resectable breast cancer involving four or more axillary nodes.

The results of both retrospective and prospective studies suggest that the effectiveness of systemic adjuvant chemotherapy with doxorubicin and cyclophosphamide for breast cancer may be related to the dose intensity of these agents. Recent trials also have demonstrated the high activity of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) against metastatic breast cancer. Clinically, paclitaxel appears to be noncross-resistant with doxorubicin, but the unique and overlapping toxicities of these three agents might preclude concurrent adjuvant administration. A possible solution is sequential rather than concurrent administration, an approach that kinetic modelling predicts to be superior. A pilot study testing dose-intensive sequential administration of doxorubicin/paclitaxel/cyclophosphamide enrolled 42 patients with a median age of 42 years who had resected breast cancer metastatic to four or more ipsilateral axillary lymph nodes. Intravenous treatment, given at 14-day intervals, began with three cycles of doxorubicin 90 mg/m2, followed by three cycles of paclitaxel 250 mg/m2, given as a 24-hour infusion, and, finally, three cycles of cyclophosphamide 3 g/m2. Selected patients received radiotherapy. The median number of positive lymph nodes was eight (range, four to 25), and the median tumor size was 3.0 cm (range, 0 to 11.0 cm). Granulocyte colony-stimulating factor support was given. Both hematologic and non-hematologic toxicity were substantial but manageable. Hospital admission was necessary in 62 (17%) of 369 chemotherapy cycles in 29 patients (69%). As planned, the median intertreatment interval was 14 days through all nine cycles of therapy, and the median delivered dose intensity exceeded 98% for all three agents. The median follow-up from local control surgery in December 1994 was 448 days (range, 82 to 632 days). Three patients (7.2%) had disease relapses, one during the doxorubicin portion of treatment and two (4.9%) who had completed treatment with all three agents. Sequential dose-intensive therapy with doxorubicin/paclitaxel/cyclophosphamide has manageable toxicity and, with short follow-up, is a promising new regimen suitable for randomized testing.

Adult↗

PubMed1995

Cooperative antiproliferative effects of 8-chloro-cyclic AMP and 528 anti-epidermal growth factor receptor monoclonal antibody on human cancer cells.

8-Chloro-cyclic AMP (8-Cl-cAMP), a site-selective cAMP analogue, is a specific inhibitor of type I cAMP-dependent protein kinase (PKAI) and induces growth inhibition in several human and rodent tumor cell lines. The anti-epidermal growth factor receptor (EGFR) mAb 528 is a blocking antibody able to inhibit the in vitro and in vivo growth of several human cancer cell lines that express functional EGFRs. Since enhanced levels of PKAI are generally found in tumor cells and an increase in PKAI expression is induced by transformation through a transforming growth factor alpha/EGFR autocrine pathway, we have evaluated whether treatment with mAb 528 in combination with 8-Cl-cAMP may have an additive or synergistic growth inhibitory effect on human cancer cells. A dose-dependent inhibition of monolayer cell growth was observed in two human colon cancer cell lines (GEO and CBS) and in a human breast cancer cell line (MDA-468) by treatment with either mAb 528 or 8-Cl-cAMP with 50% inhibitory concentration of 2-10 microgram/ml or 20-25 micrometer, respectively. The combined treatment with low noninhibitory doses of mAb 528 (0.25 microgram/ml) and with 8-Cl-cAMP had a more than additive growth inhibitory effect with a 3- to 5-fold reduction in the 8-Cl-cAMP 50% inhibitory concentration in all cell lines tested. This combined treatment was similarly effective in inhibiting the soft agar cloning efficiency of GEO cells. 8-Cl-cAMP treatment of GEO cells induced a dose-dependent increase in cell membrane-associated EGFRs with a maximum 3- to 4-fold increase within 48-72 h of treatment. These results suggest that a double blockade of the PKAI serine-threonine kinase-dependent and of the EGFR tyrosine kinase-dependent pathways is potentially useful in cancer therapy.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1994

The epidermal growth factor receptor as a target for therapy in breast carcinoma.

The epidermal growth factor (EGF) receptor and its ligands have an important regulatory role in breast carcinoma. We have produced a series of monoclonal antibodies (MAbs) directed against the external portion of the EGF receptor. These MAbs prevent the binding of the ligands to the receptor, block ligand-induced activation of the receptor, and can inhibit the growth of breast cancer cells both in tissue culture and in human tumor xenografts in nude mice. We have also shown that anti-EGF receptor antibodies greatly enhance the antitumor effects of chemotherapeutic agents active in breast cancer. Phase I clinical trials with single doses of MAb conducted in patients with tumors over-expressing EGF receptors demonstrated favorable pharmacokinetics, good tumor imaging, and a lack of toxicity. A human:murine chimeric antibody has been produced with comparable affinity and antitumor activity that will enable us to administer repeated doses of MAb either alone or in combination with chemotherapy. Our pre-clinical data support the concept that the EGF receptor may be an optimal target for treatment with receptor blocking antibodies, either alone or in combination with chemotherapy.

Adenocarcinoma↗

PubMed1994

Receptor blockade with monoclonal antibodies as anti-cancer therapy.

Human tumors express high levels of growth factors and their receptors, and many types of malignant cells appear to exhibit autocrine- or paracrine-stimulated growth. Therefore, antireceptor directed therapies have the potential of being useful anti-cancer agents. A series of murine monoclonal antibodies (MAbs) directed against human growth factor receptors and their corresponding growth factors have been produced. MAbs against the receptors for epidermal growth factor, Her2/Neu, transferrin, insulin-like growth factor, interleukin, (IL)-2 and IL-1 are currently being evaluated. MAbs directed against epidermal growth factor, transforming growth factor-alpha, bombesin, IL-2, and IL-6 also are under study. These MAbs have shown promising preclinical activity, and some of them are being tested in clinical trials. So far, anti-tumor responses have been observed with anti-IL-2 receptor, anti-bombesin and anti-IL-6 MAbs. Further research is focusing in the production of "chimeric" and "humanized" MAbs, in order to obviate the problem of host immune reactions.

Animals↗

PubMed1994

All-trans-retinoic acid and hexamethylene bisacetamide (HMBA) regulate TGF-alpha and Hst-1/kFGF expression in differentiation sensitive but not in resistant human teratocarcinomas.

The multipotent human teratocarcinoma (TC) cell NTera-2 clone D1 (abbreviated NT2/D1) differentiates into a neuronal lineage after retinoic acid (RA) treatment and a distinct phenotype after hexamethylene bisacetamide (HMBA) treatment. We previously reported that RA treatment of NT2/D1 cells reduces cellular cloning efficiency and nude mouse tumorigenicity. This accompanied a loss of mRNA expression of transforming growth factor-alpha (TGF-alpha) and the fibroblast growth factor kFGF, also known as hst-1 (abbreviated hst-1/kFGF). This study extends prior work by reporting that the distinct phenotype induced by HMBA also decreases cloning efficiency, tumorigenicity, and TGF-alpha and hst-1/kFGF mRNA expression in NT2/D1 cells. These RNA findings were confirmed by measurements of growth factor protein in the conditioned media of inducer-treated and untreated NT2/D1 cells. In two established human TC lines refractory to the actions of RA, N2102ep and Tera-1, RA fails to decrease expression of either growth factor despite induction of its nuclear receptor, RAR-beta. However, HMBA induces morphologic maturation and down-regulation of these growth factors in N2102ep cells. This indicates that the loss of TGF-alpha and hst-1/kFGF expression serves as a new marker of differentiation in human TCs. To explore the effects of these growth factors on growth and differentiation of NT2/D1 cells, TGF-alpha or hst-1/kFGF protein was added following inducer treatment or no treatment. Neither growth factor blocked immunophenotypic differentiation, but both promoted the growth of uninduced NT2/D1 cells in cloning assays.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetamides↗

PubMed1993

Antitumor effect of anti-epidermal growth factor receptor monoclonal antibodies plus cis-diamminedichloroplatinum on well established A431 cell xenografts.

We have explored the therapeutic effects of anti-epidermal growth factor receptor monoclonal antibodies (MAbs) 225 and 528 on well established A431 epidermoid carcinoma xenografts, approximately 400 mm3 (1 cm in diameter) at the start of treatment. In previous reports we demonstrated that MAbs 225 and 528 prevented the growth of A431 cell xenografts in nude mice when treatment was begun on the day of tumor cell inoculation. Since anti-epidermal growth factor receptor MAb therapy of well established tumors was unable to retard growth, we explored combination therapy with MAb plus the chemotherapeutic agent cis-diamminedichloroplatinum (cis-DDP). Additive and concentration-dependent growth-inhibitory effects of MAb with cis-DDP were observed in cultures of A431 cells. Neither intensive treatment with 225 MAb (1 mg/mouse, i.p. on day 8 after tumor inoculation, and twice weekly for 4 weeks) nor a maximally tolerated single dose of cis-DDP [150 micrograms/25 g (6 mg/kg) mouse weight, i.p. on day 8] had significant effects on tumor growth. However, the two treatments in combination resulted in substantial xenograft growth inhibition, compared with both an untreated control group and animals treated with a single modality. When a second dose of cis-DDP (150 micrograms/25 g) was added after 10 days, combination therapy with 225 MAb produced striking antitumor effects. At the end of 1 month tumor xenografts had disappeared in all but one mouse, and no tumor relapses occurred during 6 months of observation. Identical results were obtained with anti-epidermal growth factor receptor MAb 528 in combination with cis-DDP. The results of these studies provide a novel approach to the treatment of well established tumor xenografts, which may have application in the therapy of human malignancies.

Animals↗

PubMed1993

Antitumor effects of doxorubicin in combination with anti-epidermal growth factor receptor monoclonal antibodies.

BACKGROUND: A variety of human tumors frequently express high levels of epidermal growth factor (EGF) receptor and its ligand, transforming growth factor alpha (TGF-alpha), which in some tumors is associated with poor prognosis. Monoclonal antibodies (MAbs) that block the binding of TGF-alpha or EGF to the receptor can inhibit proliferation of tumor cells that express the receptor. Studies suggest that these MAbs may enhance the antitumor effects of chemotherapy. PURPOSE: Our purpose was to study, in vitro and in vivo, the antitumor effects of doxorubicin in combination with anti-EGF receptor MAbs against tumor cells expressing high levels of EGF receptor. Our goal was to achieve maximum initial cytoreduction with high-dose doxorubicin in association with prolonged blockade of EGF receptor with MAbs. METHODS: Anti-EGF receptor MAbs 528 (isotype IgG2a) and 225 (isotype IgG1) were used in combination with doxorubicin against cells from human A431 squamous cell carcinoma and human MDA-468 breast adenocarcinoma. Both A431 and MDA-468 cells express high levels of EGF receptors and TGF-alpha. Cultured cells were treated with doxorubicin (range, 0-10 nM) in the presence or absence of MAb 528 or 225 (range, 0-30 nM). At 48 hours, doxorubicin-containing medium was removed, and treatment with antibody was continued for 5 days, when cell proliferation assays were performed. The activity of the agents and the combinations against well-established xenografts in BALB/c nude mice was also studied. In nude mice, doxorubicin was given at doses of 50-100 micrograms/20 g body weight on 2 successive days, and MAbs 528 and 225 were given at a dose range of 0-2 mg intraperitoneally twice a week. RESULTS: MAbs 528 and 225 both enhanced the antitumor effects of doxorubicin against A431 and MDA-468 tumor cells, producing additive growth suppression in cell cultures. MAb 528 increased the antitumor effects of doxorubicin by 32%-42%, and similar results were obtained with MAb 225. In BALB/c athymic mice, the treatment of well-established xenografts with either doxorubicin or anti-EGF receptor MAb alone temporarily inhibited growth, but the combination of both agents substantially enhanced antitumor activity over that of doxorubicin alone in A431 and MDA-468 cell xenografts. The combination treatment of mice bearing A431 xenografts resulted in tumor eradication of 40%-100% in the surviving mice in several independent experiments. The enhanced antitumor activity was dose dependent. CONCLUSIONS: Our results suggest that anti-EGF receptor MAbs substantially enhance the effects of doxorubicin against well-established xenografts of tumor cells expressing high levels of EGF receptors. IMPLICATIONS: Clinical trials with anti-EGF receptor MAbs are being conducted, and trials with anti-EGF receptor MAbs combined with doxorubicin are planned.

Adenocarcinoma↗

PubMed1993

Differential expression of the epidermal growth factor receptor and its ligands in primary non-small cell lung cancers and adjacent benign lung.

The epidermal growth factor receptor (EGFR) and one of its ligands, transforming growth factor alpha (TGF-alpha), are thought to function as a potential autocrine loop in non-small cell lung cancer (NSCLC). However, the expression pattern of EGFR and the TGF-alpha-related ligands have not been fully characterized in primary NSCLC and adjacent benign lung tissue. For this reason, we comprehensively examined the coexpression and differential expression of EGFR and its ligands, TGF-alpha, epidermal growth factor (EGF), and amphiregulin (AR), by Northern analysis, in paired samples of primary tumors and uninvolved lung. For those RNA species overexpressed in malignant lung, single cell expression patterns were studied by immunohistochemistry. Specimens were obtained from 57 consecutive patients who underwent resection of carefully staged resectable NSCLC and were followed prospectively. Most (112 of 114) tissue samples yielded high-quality RNA. EGFR was expressed in 82 of 88 (93%) tissue samples, while TGF-alpha was expressed in 62 of 72 (86%) samples, and AR was expressed in 64 of 70 (92%) samples. EGF was unexpressed in total cellular RNA in both tumor and uninvolved lung. In a comparison of RNA expression patterns in tumors and uninvolved lung, overexpression of EGFR was found in 45% (22 of 44) of tumors, while overexpression of TGF-alpha was seen in 61% (22 of 36) of tumors, and decreased expression of AR was seen in 63% (22 of 35) of tumors. Cell type and stage did not influence differential expression, indicating that this is a frequent event in primary NSCLC. Simultaneous overexpression of EGFR and TGF-alpha was seen in only 38% of tumors. Simultaneous overexpression of EGFR and decreased expression of AR were seen in only 21% of tumors. Thus far, the differential expression of EGFR, TGF-alpha, and AR does not correlate with either disease-free or overall survival. These findings indicate that histologically dissimilar tumors can express similar components of autocrine or paracrine growth factor loops. Differential expression of EGFR and its ligands in tumor specimens compared to uninvolved lung is a common event in NSCLC and may participate in tumor growth without necessarily influencing tumor progression or histology.

Adenocarcinoma↗

PubMed1993

Acquired immune deficiency syndrome-related pulmonary non-Hodgkin lymphoma regressing after zidovudine therapy.

BACKGROUND: Zidovudine is a thymidine analogue that has been reported to have antiviral and antineoplastic activity in vitro. METHODS: The case of a patient with acquired immune deficiency syndrome (AIDS) and a pulmonary non-Hodgkin lymphoma treated with zidovudine and no other treatment is presented. RESULTS: The patient achieved a prolonged partial remission of a pulmonary non-Hodgkin lymphoma while receiving zidovudine alone. CONCLUSIONS: Zidovudine may have antitumor effects in AIDS-related lymphomas and should be evaluated for its antitumor potential.

Adult↗