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D S Alberts

Publications and source records attributed to D S Alberts.

At least 19 recordsLinked to original sources

Antineoplastic drugs sulindac sulfide and sulfone inhibit cell growth by inducing apoptosis.

The nonsteroidal anti-inflammatory drug sulindac is known to inhibit chemical carcinogenesis in rodent models and cause regression of adenomas in patients with adenomatous polyposis coli. Sulindac is a prodrug that is metabolized to a pharmacologically active sulfide derivative that potently inhibits prostaglandin synthesis. Recent studies, however, have shown that a sulfone derivative of sulindac, which essentially lacks prostaglandin synthesis inhibitory activity, also inhibits chemical carcinogenesis, suggesting that reduction of prostaglandin levels is not necessary for the antineoplastic activity of this class of drugs. Both sulindac sulfide and the sulfone inhibit the growth of cultured tumor cells, although the cellular mechanism(s) responsible for the antineoplastic activity of sulindac derivatives is unknown. In this study, we investigated the effects of sulindac sulfide and sulfone on the proliferation, differentiation, and apoptosis of HT-29 human colon carcinoma cells. Sulindac sulfide and sulfone significantly reduced cell number in both preconfluent and confluent cultures of HT-29 cells with the sulfide showing approximately 4-fold greater potency. In addition to HT-29 cells, both drugs inhibited the growth of a variety of tumor cell lines derived from other tissues, as well as normal epithelial cells and fibroblasts. Neither sulindac sulfide nor sulfone inhibited cell proliferation under conditions where the drugs were growth inhibitory. Only under specific conditions involving mitogenic stimulation did sulindac sulfide and sulfone cause cell cycle arrest. Neither sulindac sulfide nor the sulfone induced differentiation of HT-29 cells, but both drugs strongly induced apoptosis. The apoptotic response to sulindac sulfide and sulfone was both time- and dose-dependent and involved a mechanism independent of their inhibitory effect on cell cycle progression. These data suggest that apoptosis is responsible for the cell growth inhibitory activity of sulindac sulfide and sulfone and represents a potential mechanism for the antineoplastic activity of these drugs.

Anti-Inflammatory Agents, Non-Steroidal

Amino-substituted 2-[2'-(dimethylamino)ethyl]-1,2-dihydro-3H- dibenz[de,h]isoquinoline-1,3-diones. Synthesis, antitumor activity, and quantitative structure--activity relationship.

Sets of 2-[2-(dimethylamino)ethyl]-1,2-dihydro-3H- dibenz[de,h]isoquinoline-1,3-diones with amino and actylamino groups at each of the eight positions on the anthracene nucleus were synthesized from appropriately substituted anthracenes. Their evaluation in in vitro antitumor and cardiotoxicity assays revealed a very strong dependence of potency on the position of substitution. Certain compounds, including the 4-, 5-, 7-, and 9-amino derivatives, showed significantly higher potency than the unsubstituted parent compound, azonafide. Among them, 7-aminoazonafide had low cardiotoxicity relative to cytotoxicity. In general, the acetylamino analogues were less potent than the amino derivatives against tumor cells and neonatal rat heart myocytes; however, 5-(acetylamino)azonafide was highly cardiotoxic. 9-Aminoazonafide was more efficacious than azonafide or amonafide against P388 leukemia in mice. Statistically significant correlations were made between the ability of amino analogues to increase the transition melt temperature (delta Tm) of DNA and their potency against solid tumors, leukemia cells, or cardiac myocytes.

Adenine

Phase II study of 13-cis-retinoic acid plus interferon-alpha 2a in heavily pretreated squamous carcinoma of the cervix.

The combination of 13-cis-retinoic acid (13-cRA) and interferon (IFN)-alpha 2a has been reported to be highly active in previously untreated squamous carcinoma of the cervix. In this phase II study, 13-cRA was given at a dose of 1 mg/kg/day and IFN-alpha 2a was given subcutaneously at a dose of 3 million units/m2/day. Thirteen of 14 patients enrolled in this study are evaluable for response and toxicity. There were no complete or partial responses. Ten patients had progressive disease and the remaining three had stable disease. Principle toxicities were fatigue, nausea, and vomiting. This regimen appears cross-resistant with radiotherapy and/or platinum-based cytotoxic therapy in heavily pretreated patients with squamous carcinoma of the cervix.

Adult

A phase II trial of piroxantrone in advanced ovarian carcinoma after failure of platinum-based chemotherapy: Southwest Oncology Group Study 8904.

A phase II trial of the new anthrapyrazole piroxantrone was conducted by the Southwest Oncology Group in advanced ovarian carcinoma. The objective were to evaluate its response rate and toxicity in patients who had disease persistence, progression, or recurrence either during or after platinum-containing chemotherapy. A two-stage statistical design targeted accrual to 15 eligible patients if no responses were observed. The piroxantrone starting dose was 120 mg/m2, with the provision to escalate to 150 and 180 mg/m2. There were 16 eligible patients, all of whom had received either one (12 patients) or two (4 patients) prior platinum-containing regimens; one patient had received doxorubicin. Fourteen of the 16 patients were enrolled either at the time of disease persistence/progression during initial chemotherapy or with recurrence or progression within 6 months of the previous platinum-based remain. One to 5 cycles of piroxantrone were given. Dose escalation was feasible in 7 patients but was prevented in the other 9 by neutropenia. Maximum toxicity for all cycles was none or grade 1 in 2 patients; grade 2, 5; grade 3, 8; and grade 4, 1. All but one of the grade 3 or 4 events was from myelosuppression; there were no adverse cardiac events. No responses were observed. Thus, piroxantrone appears inactive in patients with persistent, progressive, or recurrent ovarian cancer who recently had received a platinum-based regimen.

Adult

An overview of clinical cancer chemoprevention studies with emphasis on positive phase III studies.

Cancer prevention aims to halt or reverse the development and progression of precancerous cells through the use of noncytotoxic nutrients and/or pharmacologic agents during the lengthy time period between tumor initiation and frank malignancy. This paper reviews cancer chemoprevention studies and focuses on Phase III trials, which are large, randomized, placebo-controlled studies that usually last several years. Studies may include multiple agents and dose levels, long-term toxicity evaluations or the modulation of surrogate endpoint biomarkers. Sample sizes of individual studies vary depending on statistical concerns and the demographics of the subject population. Recent Phase III trials include several promising agents: retinol; the retinoids 13-cis retinoic acid, all-trans-retinoic acid and 4-hydroxyphenyl retinamide; beta-carotene; finasteride and tamoxifen. Because one of the many actions of retinoids is the induction of epidermal differentiation, clinical trials with this class of agents have largely been conducted in epithelial or squamous cell tumor types. Several Phase III studies that have targeted the reversal of premalignant lesions or the prevention of second primary tumors have shown promising positive results. In contrast, some studies have shown that chemopreventive agents may have limited activity against the recurrence or progression of cells that have already undergone malignant transformation. Thus, the role of chemoprevention appears to lie in reversal of the premalignant process rather than suppression of malignant growth.

Antineoplastic Agents

Cisplatin-associated neurotoxicity: can it be prevented?

Neurotoxicity remains the major dose-limiting toxicity of cisplatin. Peripheral sensory neuropathy, the primary type of cisplatin neurotoxicity, has been reported in 30-100% of patients with clinical symptoms typically developing after cumulative cisplatin doses of > or = 300 mg/m2. Several clinical studies have established an important dose-response, dose intensity-response and cumulative total dose-response relationship for cisplatin in the treatment of head and neck, testicular, melanoma, and ovarian cancers. In patients with these tumor types, the occurrence of moderate or severe neuropathy presents an important therapeutic dilemma. Several types of agents--including micleophilic sulfur thiols, neurotrophic factors, phosphonic acid antibiotics and free oxygen radical scavengers--have been investigated for amelioration of cisplatin-related neurotoxicity. Of these, amifostine is likely to be the first neuroprotective agent widely used to enhance the clinical effectiveness of cisplatin. Recently reported results from a multicenter phase III trial of women with advance ovarian cancer receiving combination chemotheraphy with cisplatin plus cyclophosphamide showed that amifostine pretreatment was associated with moderate but significant reductions in cisplatin-associated peripheral neuropathy, tinnitus and nephrotoxicity, while achieving equivalent pathological response rates and median survival. Preclinical data suggest that several additional agents, especially the neurotropic factors nerve growth factor, insulin-like growth factor-I and neurotrophin-3, merit further investigation. Nerve growth factor is the only agent reported to prevent, rather than partially protect, cisplatin-induced neuropathy in an experimental model.

Animals

Carboplatin versus cisplatin in ovarian cancer.

The predominant data from clinical trials of advanced ovarian cancer have documented that carboplatin is equivalent to cisplatin in activity and causes considerably less ototoxicity, neurotoxicity, and nephrotoxicity. A large meta-analysis of over 2,000 patients entered into phase III clinical studies showed that patients with advanced ovarian cancer had virtually identical survival durations when treated with carboplatin- versus cisplatin-containing regimens. Furthermore, in the recent National Institutes of Health Consensus Conference on Ovarian Cancer, it was concluded that "data from mature randomized clinical trials have indicated that the combination of carboplatin and cyclophosphamide is effective therapy" and that "the substitution of carboplatin for cisplatin leads to more acceptable toxicity." Cisplatin appears to be the analog of choice for intraperitoneal therapy, which has proven superior to intravenous (IV) therapy in a recently completed intergroup study. Thus, both analogs are likely to play an important role in therapy of curative intent for patients with stage III, optimal disease. Now that paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) has proven to be an essential first-line agent in combination with cisplatin or carboplatin in the management of previously untreated, advanced disease, several new strategies have been developed. In the setting of phase III clinical trials by the Gynecologic Oncology Group (GOG) and the Southwest Oncology Group's (SWOG) Gynecologic Cancer Committee, for example, GOG-114/SWOG-9227 compares the standard IV paclitaxel/cisplatin regimen to a dose-intensive regimen incorporating two courses of carboplatin (area under the concentration-time curve = 9 mg/mL/min) plus intraperitoneal cisplatin/IV paclitaxel. The planned GOG replacement for this study will compare the standard IV paclitaxel (24-hour infusion)/cisplatin regimen to a paclitaxel (3-hour infusion)/carboplatin regimen. In the SWOG, two different high-dose regimens followed by autologous bone marrow transplantation are being evaluated in the setting of a phase II randomized trial. These regimens include high-dose carboplatin/cyclophosphamide/mitoxantrone and high-dose cisplatin/cyclophosphamide/thiotepa. The results of these and other GOG and SWOG trials will dictate the management of advanced ovarian cancer through the end of the century.

Antineoplastic Combined Chemotherapy Protocols

Chemoprevention of cervical cancer with folic acid: a phase III Southwest Oncology Group Intergroup study.

Several epidemiological reports and experimental investigations have suggested a preventive role for folic acid in the etiology of cervical cancer. The effect of p.o. folic acid supplementation on the natural history of cervical intraepithelial neoplasia (CIN) was evaluated in a multiinstitutional prospective, randomized, double-blind, placebo-controlled trial. Three hundred thirty-one women with biopsy-proven koilocytic atypia, mild CIN, or moderate CIN were randomized to receive oral folic acid (5 mg) or a similar-appearing placebo daily for 6 months following a 1-month run-in placebo period. Colposcopy, Papanicolaou smear, and serum vitamin levels (folate, retinol, alpha-tocopherol, beta-carotene, and retinyl palmitate) were monitored every 3 months. Demographic, medical, dietary, and sexual history data were obtained from personal interviews. The primary end point of the study was improvement in both Papanicolaou smear and colposcopic picture after 3 and 6 months of treatment as compared to the start of treatment. After 6 months of treatment there was no significant difference between the two study groups in the percentage of patients improved. Median serum folate levels in the treatment arm at 3 and 6 months (29.0 and 20.0 micrograms/dl) were significantly higher than those in the placebo arm (7.8 and 7.1 micrograms/dl, respectively). Mean serum levels of retinol, retinyl palmitate, alpha-tocopherol, and beta-carotene did not differ significantly between the two treatment arms. Our data support the conclusion that supplementation with folic acid (5 mg/day) does not enhance the regression of early epithelial abnormalities of the cervix.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral

Analysis of the p53 gene in human precancerous actinic keratosis lesions and squamous cell cancers.

A biomarker of skin cancer would be beneficial in evaluating the efficacy of potential cancer chemoprevention agents. To this end, we investigated the tumor suppressor gene p53 in precancerous actinic keratosis lesions (AK) and malignant squamous cell carcinomas (SCCs) using polymerase chain reaction and single-strand conformation polymorphism analysis (PCR-SSCP) techniques. In addition, p53 protein expression was evaluated using immunohistochemistical analysis with the PAB 1801 monoclonal antibody. Nine out of 13 (69%) SCCs and 8 of 15 (53%) AKs were positive for p53 mutations. In contrast, normal skin samples were negative for p53 mutations. Sequence analysis of AKs and SCCs showed primarily C to T transition mutations. Nuclear immunochemical staining for p53 was observed in 12/15 (80%) AK and 12/13 (92%) SSCs. These results suggest that p53 mutations may be involved in the malignant conversion of AKs to SCCs and that p53 may be useful as a biomarker to study the potential modulatory effects of cancer chemopreventive agents against skin cancer.

Base Sequence

Dose de-escalation chemoprevention trial of alpha-difluoromethylornithine in patients with colon polyps.

BACKGROUND: alpha-Difluoromethylornithine (DFMO) is a potent inhibitor of carcinogenesis in experimental animal models. In these animal models, DFMO has been especially active in preventing carcinogen-induced epithelial cancers, including those of the skin, colon, breast, and urinary bladder. Although DFMO is known to exert its diverse biological effects by suppressing intracellular pools of the polyamines putrescine and spermidine, the precise mechanism by which polyamine depletion, induced by DFMO, suppresses carcinogenesis is unknown. PURPOSE: The specific aim of our study was to determine the lowest dose of DFMO that would deplete target tissue (colorectal mucosa) levels of these polyamines in humans who had undergone prior removal of colon polyps while producing minimal toxic effects. METHODS: A dose de-escalation chemoprevention trial of DFMO was conducted in 111 patients (36 female and 75 male) who were in generally good health, aged 39-79, and who had undergone colonoscopy for surgical removal of an adenomatous colon polyp greater than 3 mm within 5 years prior to entering the study. Groups of patients (12-20 patients per group) were orally treated with single, daily doses of DFMO ranging from 3.0 to 0.1 g/m2 for 4 weeks (28 days). Prior to initiation of DFMO treatment and at the end of treatment, six colorectal biopsy specimens were collected from each patient, along with serum samples. All biopsies were performed between 9 AM and noon to avoid possible effects of diurnal variations in laboratory end points. Samples for analysis of plasma DFMO levels were also collected during this time period on the day after the last day of drug administration. RESULTS: DFMO caused a decrease in both putrescine content and the ratio of spermidine to spermine for all dose groups down to 0.25 g/m2. Both putrescine content and the ratio of spermidine to spermine and changes in these parameters as a function of DFMO treatment decreased as a function of donor age. None of the 30 patients receiving either 0.25 or 0.5 g/m2 experienced any clinical ototoxicity in this trial. CONCLUSIONS: DFMO is both safe and effective in reducing colorectal mucosal polyamine contents when it is administered orally to patients at doses as low as 0.25 g/m2 for 28 days. No ototoxicity was observed at doses up to twice this amount. IMPLICATIONS: If DFMO is also found to be effective in suppressing polyamine contents in other target tissues, it may be useful in preventing a wide range of human epithelial cancers, including those of the prostate and breast.

Administration, Oral

Enhancement of regression of cervical intraepithelial neoplasia II (moderate dysplasia) with topically applied all-trans-retinoic acid: a randomized trial.

BACKGROUND: Retinoids enhance differentiation of most epithelial tissues. Epidemiologic studies have shown an inverse relationship between dietary intake or serum levels of vitamin A and the development of cervical dysplasia and/or cervical cancer. Pilot and phase I investigations demonstrated the feasibility of the local delivery of all-trans-retinoic acid (RA) to the cervix using a collagen sponge insert and cervical cap. A phase II trial produced a clinical complete response rate of 50%. PURPOSE: This randomized phase III trial was designed to determine whether topically applied RA reversed moderate cervical intraepithelial neoplasia (CIN) II or severe CIN. METHODS: Analyses were based on 301 women with CIN (moderate dysplasia, 151 women; severe dysplasia, 150 women), evaluated by serial colposcopy, Papanicolaou cytology, and cervical biopsy. Cervical caps with sponges containing either 1.0 mL of 0.372% beta-trans-RA or a placebo were inserted daily for 4 days when women entered the trial, and for 2 days at months 3 and 6. Patients receiving treatment and those receiving placebo were similar with respect to age, ethnicity, birth-control methods, histologic features of the endocervical biopsy specimen and koilocytotic atypia, and percentage of involvement of the cervix at study. Treatment effects were compared using Fisher's exact test and logistic regression methods. Side effects were recorded, and differences were compared using Fisher's exact test. RESULTS: RA increased the complete histologic regression rate of CIN II from 27% in the placebo group to 43% in the retinoic acid treatment group (P = .041). No treatment difference between the two arms was evident in the severe dysplasia group. More vaginal and vulvar side effects were seen in the patients receiving RA, but these effects were mild and reversible. CONCLUSIONS: A short course of locally applied RA can reverse CIN II, but not more advanced dysplasia, with acceptable local side effects. IMPLICATIONS: A derivative of vitamin A can reverse or suppress an epithelial preneoplasia, lending further support to the notion that chemoprevention of human cancer is feasible.

Administration, Intravaginal

Simple numeric abnormalities as primary karyotype changes in ovarian carcinoma.

Simple near-diploid karyotypes in ovarian cancer may indicate either primary alterations related to tumor pathogenesis or abnormalities associated with early tumor progression. We have identified a series of 13 epithelial ovarian tumors with very simple karyotypes. Specifically, these karyotypes were near-diploid and displayed numeric abnormalities alone or combined with one or two structural alterations. The present series includes samples from 10 patients with newly diagnosed adenocarcinomas and 3 patients having borderline malignancies. Recurrent numeric abnormalities were identified and included 9/13 cases (69%) with +12, eight cases (62%) with +8, five cases (38%) with +7, three cases (23%) each with +3 or +5, and two cases (15%) with -X. Five cases in this series displayed certain numeric abnormalities (+12, +7, and -X) as the sole anomalies, thereby qualifying as primary karyotype changes. Of the 6 cases with structural abnormalities, 4 involved chromosome 19, 2 involved chromosome 1, and the remaining abnormalities or translocation partners involved other chromosomes. These findings indicate that some numeric abnormalities are primary karyotype alterations in patients with malignant epithelial ovarian tumors and that chromosome 19 may be preferrentially involved in structural rearrangements during early tumor progression.

Adult

Strategy and planning for chemopreventive drug development: clinical development plans. Chemoprevention Branch and Agent Development Committee. National Cancer Institute.

At the National Cancer Institute, Division of Cancer Prevention and Control, the Chemoprevention Branch and Agent Development Committee develop strategies for efficiently identifying, procuring, and advancing the most promising drugs into clinical trials. Scientific expertise is applied at each phase of development to critically review the testing methods and results, and to establish and apply criteria for evaluating the agents for further development. The Clinical Development Plan, prepared by the Chemoprevention Branch and the Agent Development Committee, is a summary of the status of the agent regarding evidence for safety and chemopreventive efficacy in preclinical and clinical studies. It also contains the strategy for further development of the drug that addresses pharmacodynamics, drug effect measurements, intermediate biomarkers for monitoring efficacy, toxicity, supply and formulation, regulatory approval, and proposed clinical trials. Sixteen Clinical Development Plans are presented here: N-acetyl-l-cysteine (NAC), aspirin, calcium, beta-carotene, 2-difluoromethylornithine (DFMO), DHEA analog 8354, 18 beta-glycyrrhetinic acid, N-(4-hydroxyphenyl)retinamide (4-HPR), ibuprofen, oltipraz, piroxicam, Proscar, sulindac, tamoxifen, vitamin D3 and analogs, and vitamin E. The objective of publishing these plans is to stimulate interest and thinking among the scientific community on the prospects for developing chemopreventive drugs.

Clinical Trials as Topic

In vitro drug testing of ovarian cancer using the human tumor colony-forming assay: comparison of in vitro response and clinical outcome.

The purpose of this study was to assess the prognostic value of in vitro drug chemosensitivity testing using the Hamburger-Salmon human tumor colony-forming assay (HTCA) in fresh tumor samples obtained from newly diagnosed patients with stage II-IV ovarian cancer undergoing maximum cytoreductive surgery and prior to platinum-based chemotherapy. The HTCA was performed on fresh ovarian cancers obtained from 93 patients at their initial exploratory laparotomy to evaluate in vitro sensitivity to cisplatin, carboplatin, and cyclophosphamide following a 1-hr drug exposure. Prospective clinical follow-up was performed on all patients with the primary study endpoints being pathologically proven complete response at second-look surgery and disease-free and overall survival durations. In vitro drug sensitivity was strongly dose-dependent. At a concentration of 5 micrograms/ml only 23% of tumor samples were sensitive (as defined by a > or = 50% decrease in tumor colony-forming units compared to controls) to cisplatin; 13% of tumors were sensitive to carboplatin at a concentration of 50 micrograms/ml and 11% to 4-OH-cyclophosphamide at a concentration of 1 microgram/ml. At doses which were 10 times the previously stated concentrations, the sensitivity rates to cisplatin, carboplatin, and 4-OH-cyclophosphamide increased to 72, 63, and 53%, respectively. Subjects were categorized as having drug-sensitive disease if HTCA results showed in vitro drug sensitivity to at least one of the agents used in their primary chemotherapy. Multivariate analysis failed to show any advantage in clinical response rate, progression-free interval, or survival duration for patients with drug-sensitive disease compared to drug-resistant disease; however, there was evidence of a trend toward an enhanced pathologically proven complete response rate in patients who had chemosensitive tumors in vitro. Second-look surgery was performed in 28 of 55 patients with optimal surgical resections and no clinical evidence of disease at the completion of their primary chemotherapy. Fifty percent (5/10) of patients with drug-sensitive disease achieved a pathologic complete response, while only 3/18 (17%) patients with drug-resistant tumors had a documented pathologic complete response (P = 0.13). As reported in other ovarian cancer studies, patient characteristics which were found to be significantly associated with survival were stage of disease (II-III vs IV), optimal primary surgical resection (i.e., < 1 cm2 residual tumor) vs suboptimal resection, clinical measurability of disease at initiation of chemotherapy, and response to primary chemotherapy. In conclusion, in vitro drug sensitivity, as measured by the HTCA, does not appear to be an independent prognostic factor for survival in patients with stage II-IV epithelial ovarian cancer who undergo standard treatment with tumor debulking surgery and primary platinum-based chemotherapy.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult

Inhibiting intracellular signalling as a strategy for cancer chemoprevention.

The intracellular signalling pathways that mediate the effects of growth factors and oncogenes on cell growth and transformation offer potential targets for the development of chemopreventive agents that prevent the progression of premalignant cells to invasive cancer. Agents acting on signalling targets would be expected to be cytostatic rather than cytotoxic agents. A number of existing chemopreventive agents exhibit, among their properties, inhibition of intracellular signalling enzymes. It is possible that this activity accounts, at least in part, for their chemopreventive properties.

Animals

Carotenoids, tocopherols, and retinoids in human buccal mucosal cells: intra- and interindividual variability and storage stability.

The baseline, intra-, and interindividual variability as well as storage stability of carotenoids, tocopherols, and retinoids in human buccal mucosal cells were determined because this information is lacking. All the buccal mucosal cell samples were collected after an overnight fast. In the variability study, 154 subjects (median age 57.5 y) provided three samples each at 7-10-d intervals over a 1-mo period. In the stability study, 13 young volunteers provided four samples each before and during the 11 d of oral administration of beta-carotene, alpha-tocopherol, and vegetable juice; the cells were pooled and stored as a pellet at -80 degrees C. Eleven micronutrients were analyzed simultaneously with HPLC. The results indicated that 1) lycopene and beta-carotene were the two major carotenoids, retinol was not detected in most cell samples; 2) the intra-individual variability was small, but the interindividual variability was very large; 3) two measurements of micronutrient concentration in fasting buccal mucosal cells should be adequate to establish a representative baseline for each micronutrient; and 4) the micronutrients under the storage conditions were stable for > or = 8 mo.

Administration, Oral