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G W Sledge

Publications and source records attributed to G W Sledge.

At least 55 records · Page 3Linked to original sources
PubMed1999

Metastatic breast cancer: the role of chemotherapy.

Treatment of metastatic breast cancer remains in flux. A flurry of new chemotherapeutic agents with activity against this disease has been identified in recent years, yet breast cancer remains a cause of significant morbidity and mortality. The taxanes in particular appear to hold promise for improved outcome and, in fact, are the treatment of choice for salvage therapy. Using the taxanes in high-dose regimens, with stem cell transplantation, in alternative schedules, and in combination regimens, including with biologic treatments, is the focus of future potential advances. Continued investigative energy and the discovery of novel drugs and therapeutic approaches for addition to established techniques hopefully will improve outcomes in the next generation of treatment strategies for metastatic breast cancer.

Antineoplastic Agents, Phytogenic↗
PubMed1999

Breast cancer: challenges and opportunities.

The pace of research in breast cancer has picked up significantly in recent years, due to both increased public awareness and improved technology. The availability of many new agents in an already crowded field has resulted in several challenges (both practical and conceptual) for the research community. This report suggests that the "business-as-usual" approach to drug development has important limitations rendering it inadequate to the current research climate. Future drug development, in the form of biologically targeted therapies, offers the best hope for defeating this disease.

Angiogenesis Inhibitors↗
PubMed1998

Characterization of multiple 12p rearrangements in testicular germ cell tumor cell line 833K and its subclone 64CP by chromosome microdissection.

Rearrangements of chromosome arm 12p are known to be common in germ cell tumors (GCT). Previous studies, using fluorescence in situ hybridization (FISH) with a whole chromosome 12 painting probe, showed unusual distributions of chromosome 12-derived chromatin in GCT cell line 833K and its cisplatin-resistant subclone, 64CP, located next to AgNOR (silver staining nucleolus organizer regions), some of which were ectopic. In this study, the ectopic stalk regions were shown by FISH to be composed of 18s and 28s rDNA, but were flanked by beta-satellite DNA, which may form a barrier around the rDNA. In order to determine the specific origins of the rearranged chromosome 12 segments, three different derived chromosome 12 regions were isolated from 64CP, using chromosomal microdissection. The microdissected fragments were labeled and hybridized by FISH to normal human chromosomes. All three segments localized to distal 12p; 12p12-->12pter, but with apparently different breakpoints for each segment. Furthermore, three-color FISH experiments with 12p band-specific probes demonstrated that the derivative chromosome 12 regions in 833K also originate from distal 12p (12p12-->p13). These sequences now can be evaluated for degree of overlap or common breakpoints which may be of significance in the development or progression of GCT.

Chromosome Aberrations↗
PubMed1998

Effects of doxycycline on human prostate cancer cells in vitro.

Prostate cancer is the most common form of cancer in older men and the major cause of death from prostate cancer is metastatic disease. The matrix metalloproteinases (MMPs) play a significant role in the growth, invasion and metastasis of many tumors, including those of the prostate. We previously demonstrated that doxycycline, a synthetic tetracycline, inhibits MMPs and cell proliferation and induces apoptosis in several cancer cell lines. We also demonstrated that in an in vivo model of metastatic breast cancer in athymic mice doxycycline inhibits tumor size and regrowth after resection. In the present study, gelatinolytic activity in the human prostate cancer cell line, LNCaP, was suppressed and significant inhibition of cell growth occurred after exposure to 5 or 10 microg/ml of doxycycline, while cell growth was normal in untreated cells. Radioisotope incorporation into proteins was reduced by doxycycline. DNA fragmentation, consistent with apoptosis, was demonstrated in cells treated with doxycycline. These data suggest that doxycycline may have potential utility in the management of prostate cancer.

Adenocarcinoma↗
PubMed1998

Myeloid progenitor cell proliferation and mobilization effects of BB10010, a genetically engineered variant of human macrophage inflammatory protein-1alpha, in a phase I clinical trial in patients with relapsed/refractory breast cancer.

Macrophage Inflammatory Protein (MIP)-1alpha is myelosuppressive in vitro and in vivo for hematopoietic stem and immature subsets of myeloid progenitor cells, demonstrates some myeloprotective effects in mice treated with Ara-C and hydroxyurea, and has stem/progenitor cell mobilizing activity in mice. Based on these observations, BB10010, a genetic variant of MIP-1alpha, was assessed for effects on marrow and blood myeloid progenitor cells in patients with relapsed/refractory breast cancer. MIP-1alpha readily polymerizes, whereas BB10010 has a reduced tendency to form large polymers at physiological pH and ionic strength and retains biological activity. Patients were injected with 5, 10, 30 or 100 microg/kg BB10010 s.c. daily for 3 days. BB10010 significantly reduced the cycling status of marrow myeloid progenitors from pretreatment levels of 39-58% to 0 - 11% one day after the third and last injection of BB10010. This was associated with significant decreases in frequency of marrow progenitors (number of colonies formed per number of cells plated) and percent biopsied marrow CD34+ cells. The suppressive effects were reversible in patients and the rapidity of this reversal demonstrated in mouse studies. BB10010 had no effect on nucleated cellularity or on the proliferation of nucleated cells as assessed in marrow biopsies from the patients. These latter effects may in part reflect the noted decreased apoptosis of nucleated cells by BB10010. BB10010 also demonstrated significant but modest myeloid progenitor cell mobilizing capacity. Blood progenitors were in a slow or non-cycling state prior to treatment and this did not change after administration of BB10010. The above effects of BB10010 were similar at the four different dosage levels assessed. These results demonstrate in humans the suppressive and mobilizing effects of MIP-1alpha and BB10010 previously noted in vivo in mice.

Adult↗
PubMed1998

Eastern Cooperative Oncology Group randomized trials of observation versus maintenance therapy for patients with metastatic breast cancer in complete remission following induction treatment.

PURPOSE: To investigate the value of maintenance treatment for patients with metastatic breast cancer whose disease is in complete remission (CR). PATIENTS AND METHODS: One hundred ninety-five women (141 eligible) whose disease was in CR or in CR except for bone metastases following six cycles (6 months) of doxorubicin-containing induction treatment were randomized to receive cyclophosphamide, methotrexate, fluorouracil, prednisone, tamoxifen, and halotestin [CMF(P)TH] or observation. In a previous pilot study, patients in CR after 24 months of induction treatment were randomized to continue chemotherapy for 4 more years or stop chemotherapy. RESULTS: Among patients randomized to CMF(P)TH, life-threatening toxicity included leukopenia in 3%, thrombocytopenia in 3%, cardiac in 2%, and diabetes in 1%. The median time to relapse from randomization was 18.7 months on CMF(P)TH and only 7.8 months on observation (P < .0001). The median time to death was 32.2 months on CMF(P)TH and 28.7 months on observation (P=.74). Similar results were seen in the pilot study (median time to relapse, 12.6 and 6.4 months; median survival, 37.7 and 24.2 months; study too small for statistical significance). Maintenance treatment was always the most significant covariate in time-to-relapse models. CONCLUSION: There is definite toxicity associated with CMF(P)TH maintenance treatment. When CR was obtained on induction, maintenance treatment with CMF(P)TH was never significant in survival models. However, maintenance treatment was always the most significant covariate in the time-to-relapse models, which motivates its consideration for appropriately informed patients.

Adult↗
PubMed1997

Effects of vitamin D3 on proliferation of cancer cells in vitro.

The principal cause of death from most forms of cancer is metastatic disease. Cancer cells appear to grow quickly out of the control of the normal host regulatory mechanisms. Many factors contribute to this unrestrained proliferation, including increased metalloproteinase activity causing degradation of the extracellular matrix surrounding cancer cells, angiogenesis permitting easy access of the cells to the bloodstream and decrease or loss of programmed cell death, or apoptosis, an important mechanism for removal of abnormal or senescent cells. Treatment modalities targeted towards arresting cancer cell proliferation and spread are needed to improve the survival of patients with cancer. Vitamin D3, 1,25-dihydroxychole-calciferol D3, has been shown to induce apoptosis in the human breast cancer cell line, MCF-7. We have studied the effects of three concentrations of vitamin D3 on the human breast cancer cell line, MDA-MB-435, the human prostate cancer cell line, LNCaP, and a human osteosarcoma cell line, U20S. We report here that vitamin D3 strikingly inhibits cell proliferation and induces apoptosis in all three cell lines.

Adenocarcinoma↗
PubMed1997

Inhibition of proliferation and induction of apoptosis by doxycycline in cultured human osteosarcoma cells.

Matrix metalloproteinases (MMPs) play a major role in the phenomena of growth, invasion, and metastasis of malignant disease. We studied the effects of doxycycline, a synthetic tetracycline that has been shown to suppress MMP activity in other solid tumors, on osteosarcoma (OSA) cell proliferation and MMP activity in vitro. OSA cells from 6 patients and from one established human tumor cell line (U2OS) (American Type Culture Collection) were cultured in the presence or absence of doxycycline. Doxycycline (10 microg/ml) suppressed OSA cell proliferation threefold to sevenfold in all cultures. MMP activity was assessed by gelatin zymography and was diminished by approximately 50% in all cultures. We examined the hypothesis that induction of apoptosis is one of the mechanisms by which doxycycline inhibits OSA cell proliferation. Ethidium bromide-stained gels of DNA from cells grown in the presence of 5 microg/ml and 10 microg/ml of doxycycline revealed laddering consistent with apoptosis after 24 hours in culture. The demonstration that doxycycline suppresses cell proliferation and MMP activity and induces apoptosis in human OSA cells in vitro suggests that this well-tolerated oral agent may be effective in the in vivo treatment of OSA.

Apoptosis↗
PubMed1997

Constitutive activation of NF-kappaB during progression of breast cancer to hormone-independent growth.

Breast cancers often progress from a hormone-dependent, nonmetastatic, antiestrogen-sensitive phenotype to a hormone-independent, antiestrogen- and chemotherapy-resistant phenotype with highly invasive and metastatic growth properties. This progression is usually accompanied by altered function of the estrogen receptor (ER) or outgrowth of ER-negative cancer cells. To understand the molecular mechanisms responsible for metastatic growth of ER-negative breast cancers, the activities of the transcription factor NF-kappaB (which modulates the expression of genes involved in cell proliferation, differentiation, apoptosis, and metastasis) were compared in ER-positive (MCF-7 and T47-D) and ER-negative (MDA-MB-231 and MDA-MB-435) human breast cancer cell lines. NF-kappaB, which is usually maintained in an inactive state by protein-protein interaction with inhibitor IkappaBs, was found to be constitutively active in ER-negative breast cancer cell lines. Constitutive DNA binding of NF-kappaB was also observed with extracts from ER-negative, poorly differentiated primary breast tumors. Progression of the rat mammary carcinoma cell line RM22-F5 from an ER-positive, nonmalignant phenotype (E phenotype) to an ER-negative, malignant phenotype (F phenotype) was also accompanied by constitutive activation of NF-kappaB. Analysis of individual subunits of NF-kappaB revealed that all ER-negative cell lines, including RM22-F5 cells of F phenotype, contain a unique 37-kDa protein which is antigenically related to the RelA subunit. Cell-type-specific differences in IkappaB alpha, -beta, and -gamma were also observed. In transient-transfection experiments, constitutive activity of an NF-kappaB-dependent promoter was observed in MDA-MB-231 and RM22-F5 cells of F phenotype, and this activity was efficiently repressed by cotransfected ER. Since ER inhibits the constitutive as well as inducible activation function of NF-kappaB in a dose-dependent manner, we propose that breast cancers that lack functional ER overexpress NF-kappaB-regulated genes. Furthermore, since recent data indicate that NF-kappaB protects cells from tumor necrosis factor alpha-, ionizing radiation-, and chemotherapeutic agent daunorubicin-mediated apoptosis, our results provide an explanation for chemotherapeutic resistance in ER-negative breast cancers.

Animals↗
PubMed1997

Phase II trial of biweekly paclitaxel and cisplatin in advanced breast carcinoma: an Eastern Cooperative Oncology Group study.

PURPOSE: To determine the efficacy of a biweekly paclitaxel and cisplatin regimen in patients with advanced breast carcinoma, which has previously been reported to produce an 85% response rate in such patients. PATIENTS AND METHODS: Sixteen patients with metastatic breast carcinoma who had relapsed after prior doxorubicin-containing adjuvant chemotherapy were treated with paclitaxel (90 mg/m2) by intravenous (i.v.) infusion over 3 hours followed by cisplatin (60 mg/m2) given by i.v. infusion over 1 hour on an outpatient basis. Treatment was repeated every 2 weeks if the absolute neutrophil count was > or = 750/microL and platelet count > or = 75,000/microL. After a maximum of eight cycles of paclitaxel/cisplatin, patients received biweekly paclitaxel alone (90 mg/m2 with dose escalation). Thirteen patients were assessable for response and all for toxicity. Nine of 13 patients assessable for response (69%) had at least three sites of metastases and 10 patients (77%) had visceral-dominant disease. RESULTS: Partial response occurred in three of 13 assessable patients (23%; 90% confidence interval, 7% to 49%). All responders had two or fewer sites of metastases. The median time to progression was 4.3 months and the median survival duration was 11.4 months. Patients received a median of seven cycles of therapy (range, two to 21). Severe and/or life-threatening toxicity occurred in 50% and 38%, respectively, and consisted primarily of granulocytopenia, anemia, and neuropathy. The trial was terminated after the first interim analysis as per its two-stage design, since it was unlikely that the response rate would exceed 70%. CONCLUSION: Biweekly paclitaxel/cisplatin is not likely to produce a response rate greater than 70% in patients with metastatic breast cancer who have relapsed after prior doxorubicin-containing adjuvant chemotherapy and who have multiple sites of metastases and/or visceral-dominant disease.

Adult↗
PubMed1996

A phase I trial of recombinant human interleukin-11 (neumega rhIL-11 growth factor) in women with breast cancer receiving chemotherapy.

We performed a phase I trial of recombinant human interleukin-11 (rhIL-11) in women with breast cancer. Cohorts of three to five women were accrued to five dosage levels of rhIL-11 (10, 25, 50, 75, and 100 micrograms/kg/d). rhIL-11 alone was administered by a daily subcutaneous injection for 14 days during a 28-day prechemotherapy "cycle 0." Patients (pts) subsequently received up to four 28-day cycles of cyclophosphamide (1,500 mg/m2) and doxorubicin (60 mg/m2) chemotherapy followed by rhIL-11 at their assigned dose (days 3 through 14). Sixteen pts (13 stage IV, 3 stage IIIB) were accrued to this study. Median age was 53 years and median Eastern Cooperative Oncology Group Performance Status was 0. A grade 3 neurologic event was seen in 1 pt at 100 micrograms/kg. Because of the degree of grade 2 constitutional symptoms (myalgias/arthralgias and fatigue) at 75 micrograms/kg, dose escalation was stopped and 75 micrograms/kg was the maximally tolerated dose. No other grade 3 or 4 adverse events related to rhIL-11 were seen. The administration of rhIL-11 was not associated with fever. Reversible grade 2 fatigue and myalgias/arthralgias were seen in all pts at 75 micrograms/kg. Weight gain of 3% to 5% associated with edema was seen at doses > 10 micrograms/kg but a capillary leak syndrome was not seen. rhIL-11 alone was associated with a mean 76%, 93%, 108%, and 185% increase in platelet counts at doses of 10, 25, 50, and 75 micrograms/kg, respectively. No significant changes in leukocytes were seen. A mean 19% decrease in hematocrit was observed. Acute-phase proteins increased with treatment at all doses. Compared with patients at the 10 micrograms/kg dose, patients receiving doses > or = 25 micrograms/kg experienced less thrombocytopenia in the first two cycles of chemotherapy. We conclude that rhIL-11 has thrombopoietic activity at all doses studied, is well tolerated at doses of 10, 25, and 50 micrograms/kg, and at doses > or = 25 micrograms/kg has the potential to reduce chemotherapy-induced thrombocytopenia in this model.

Adult↗
PubMed1996

Adjuvant therapy for early stage breast cancer.

Metastatic disease in women who have undergone appropriate local therapy remains the leading ultimate cause of death in breast cancer. Therapy for overt metastatic disease is unlikely to offer curative potential for any but a small proportion of patients. Therapy for micrometastatic disease is offered in the hope that patients with a smaller tumor burden will be more amenable to cure. This report will examine the extent to which this hope has been fulfilled and discuss the future of adjuvant therapy. The initial adjuvant therapy trials used chemotherapy to treat women with lymph node-positive breast cancer. These trials clearly demonstrated a disease-free and overall survival benefit for women receiving combination chemotherapy in the adjuvant setting. These benefits were subsequently extended to women with lymph node-negative disease, and (in the form of adjuvant hormonal therapy) to women with steroid receptor-positive breast cancer. Current adjuvant therapy clearly improves disease-free and overall survival in patients with micrometastatic disease. It is less clear whether these improvements translate to a "cure" in the sense of total elimination of micrometastatic disease. Numerous questions remain to be answered regarding the dose intensity of chemotherapy, the appropriate sequencing of chemotherapy agents, and the use of novel chemotherapy agents, such as the taxanes. These and other questions are the subject of ongoing clinical trials.

Adult↗
PubMed1996

Implications of the new biology for therapy in breast cancer.

It is a truism that a better understanding of the biology of breast cancer should lead to improvements in diagnosis and therapy. Despite this, our significantly improved grasp of breast cancer biology has had little direct therapeutic impact to date. The technologies used to treat breast cancer (surgery, radiation therapy, chemotherapy, and hormonal therapy) were in general developed decades ago. With the exception of the prognostic factor area, advances in biological knowledge have not translated into either new therapies or altered outcomes. Fortunately, this now appears to be changing. This paper will focus on three emerging areas in which the new biology is most likely to have a therapeutic impact. The first area involves growth factors and their receptors. It is now clear that the growth of breast cancer is regulated by growth factor receptors (eg, EGFR and Her-2/neu), and that their upregulation is associated with impaired prognosis. Growth factors and their receptors represent a promising therapeutic target, both alone and in combination with other standard agents. Recent evidence suggests that growth factors and their receptors may be important for regulating programmed cell death (apoptosis) in breast cancer. A second emerging area involves matrix metalloproteinases. Breast cancer invasion and metastasis involves and requires activation of enzymes capable of dissolving natural barriers to spread. The most heavily studied of these are the matrix metalloproteinases, for which considerable in vitro and in vivo evidence suggests an important role in breast cancer. The recent advent of compounds with matrix metalloproteinase inhibitory activity makes a therapeutic intervention against matrix metalloproteinases appear reasonable. In vivo laboratory evidence suggests that their use may occur in the very near future. A third emerging area revolves around the question of neoangiogenesis (new blood vessel formation) in breast cancer. Breast cancers (indeed, all solid tumors) are incapable of growth beyond a certain critical diameter without new blood vessel formation. Recent work has demonstrated that breast cancers produce angiogenic factors stimulating this new growth. Therapies aimed at blocking this stimulation, and preventing neovascularization represent a promising therapeutic target. Numerous agents capable of preventing new blood vessel formation have been discovered in the laboratory and are poised to enter clinical trials.

Angiogenesis Inducing Agents↗
PubMed1996

Role of paclitaxel in the treatment of breast cancer: the American Cooperative Group Experience.

Phase I and II trials to evaluate paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) as a single agent and combined with other drugs have generated considerable enthusiasm for this interesting new agent. Despite these trials, or because of them, many important questions remain regarding the use of paclitaxel. Ongoing Cooperative Oncology Group trials investigating the use of paclitaxel in breast cancer include CLB 9342, examining the question of paclitaxel dose intensity; the National Surgical Adjuvant Breast Project trial B-26, investigating the question of duration of infusion; E1193, testing the relative activity and synergy of paclitaxel and doxorubicin in a metastatic setting; and CLB 9344, focusing on the adjuvant use of paclitaxel. The cooperative groups are currently investigating novel paclitaxel-based combination therapy in phase II trials.

Antineoplastic Agents, Phytogenic↗
PubMed1996

Effects of recombinant human interleukin-11 (Neumega rhIL-11 growth factor) on megakaryocytopoiesis in human bone marrow.

We examined the effects of recombinant human interleukin 11 (rhIL-11) on in vivo human hematopoiesis. Twelve women with advanced breast cancer and no evidence of bone marrow (BM) involvement were treated with 10, 25, 50, or 75 micrograms/kg/day of rhIL-11 administered subcutaneously for 14 consecutive days. Examination of bone marrow trephine biopsies obtained before and after rhIL-11 treatment revealed unchanged BM cellularity at all doses, and a statistically significant increase in megakaryocyte (MK) frequencies (from 0.5 +/- 0.1% to 1.0 +/- 0.3%) following administration of the two highest doses (p < 0.001). The BM biopsies also showed an increased proportion of immature myeloid and erythroid precursors following 14 days of treatment in all cases. The mean proportion of marrow cells stained with PC10, a monoclonal antibody (mAb) that recognizes the proliferating cell nuclear antigen (PCNA), increased from 16.3 +/- 5.7% to 45.8 +/- 17.1% (p < 0.001) following the two highest treatment doses. Most of the PC10+ cells were promyelocytes and proerythroblasts. In this same group, the proportion of PC10+ MKs increased from 28.3 +/- 11.5% to 56.8 +/- 24.3% (p < 0.01) after treatment, while megakaryocyte ploidy analysis revealed a greater number of higher ploidy (64N) megakaryocytes following rhIL-11 treatment (p < 0.012). Numbers of BM and peripheral blood (PB) CD34+, CD34+DR+, and CD34+DR- cells did not change following rhIL-11 treatment. Following rhIL-11 therapy at the highest dose studied, a 3- and 10-fold increase in the number of committed BM MK progenitor cells (CFU-MK) was observed in two of three patients, while no change was seen in the number of the other BM or PB progenitor cells examined. rhIL-11 administration was also associated with an increase in BM reticulin content (fibrosis grade 1-2) in 7 patients. These results indicate that the administration of rhIL-11 to patients with normal hematopoiesis stimulates MK endoreduplication, PCNA expression, and, at high doses, increases MK and CFU-MK progenitor cell numbers. In addition, rhIL-11 was able to stimulate precursor cells of different marrow lineages without affecting the number of assayable progenitor cells.

Administration, Cutaneous↗
PubMed1996

Paclitaxel doublets in metastatic breast cancer: Eastern Cooperative Oncology Group and Hoosier Oncology Group Studies.

The recognition of the activity of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) in metastatic breast cancer led to attempts to combine this drug with other active agents. Two agents that have received particular attention are doxorubicin and cisplatin. Initial pilot and phase I trials by the Eastern Cooperative Oncology Group (ECOG) led to the development of a three-arm, prospective randomized trial comparing single-agent doxorubicin, single-agent paclitaxel, and the combination of doxorubicin and paclitaxel (E 1193). This trial is currently closed to accrual and the initial results are being analyzed. Based on data from Gianni et al (J Clin Oncol 13:2688-2699, 1995), the ECOG is currently involved in two trials attempting both to confirm the superior activity of the regimen used by Gianni et al and, in a phase I/II trial, to ameliorate its cardiac toxicity through the addition of dexrazoxane. Similarly, both the ECOG and the Hoosier Oncology Group were unable to confirm the strikingly positive results obtained by the Vancouver group when cisplatin was combined with paclitaxel (Semin Oncol 22:108-111, 1995 [suppl 6]: Proc Am Soc Clin Oncol 13:71, 1994 [abstr 88]). Indiana University investigators are currently involved in a phase I trial attempting to combine carboplatin and paclitaxel in a biweekly schedule.

Antibiotics, Antineoplastic↗