Search PubMed⌕ Search

Biomedical subjects

B Drewinko

Publications and source records attributed to B Drewinko.

At least 55 records · Page 3Linked to original sources
PubMed1985

Cellular basis for the inefficacy of 5-FU in human colon carcinoma.

Five established human colorectal carcinoma cell lines with distinct phenotypic properties were exposed to different concentrations of 5-FU for varying time intervals. Effects were measured by sequential cell counts and by inhibition of colony formation. Treatment for 1 hr with 1 microgram/ml barely decreased survival of all cell lines as measured by colony formation; at a concentration of 100 microgram/ml, survival was modestly reduced for all cell lines, and for concentrations of 1000 microgram/ml, survival was decreased by greater than 50%. Extending the length of the treatment interval markedly increased the degree of cell kill for all concentrations of 5-FU. Treatment for greater than 24 hrs resulted in almost complete extermination of colony-forming cells, even for relatively resistant cell lines. The effect of 5-FU treatment on cell number was more complex and depended on drug concentration, length of treatment, and type of cell line. In general, decrements in cell numbers were somewhat related to both drug concentration and length of treatment interval, especially if performed 7 days after terminating drug treatment. Earlier cell counts were inconclusive and the same result could be obtained for different drug concentrations or treatment intervals. Furthermore, these results would change on a daily basis. More important, cell count results never correlated with the survival endpoint measured by inhibition of colony formation. Our results suggest that enhancement of the currently poor performance of 5-FU in the treatment of human colon carcinoma could originate from changing the administration modality to long-term infusion.

Cell Count↗
PubMed1984

ARH-77, an established human IgG-producing myeloma cell line. I. Morphology, B-cell phenotypic marker profile, and expression of Epstein-Barr virus.

Monolayer cultures of ARH-77 cells, a human myeloma cell line propagated in vitro, display a variety of morphologic entities ranging from small lymphocytes to classic plasma cells. The cells show intense pyronin and periodic acid-Schiff affinity but are negative for colloidal iron, sudan black, and naphtol AS-D chloroacetate esterase. The cells exhibit phenotypic markers pertaining to each stage of the B-cell lineage. They fail to display sheep erythrocyte and bovine erythrocyte-IgG antibody complex rosettes, common acute lymphocytic leukemia (ALL) antigens and T-cell antigens, but most cells display surface complement receptors, Ia-like antigens, and surface and intracytoplasmic Ig. Monoclonal antibodies were negative for T-antigens, myelomonocytic cell antigens, leukemia-associated antigens, and BA-1 and OKT-10 antigens. However, 100% of the cells were positive with OKT-9 and B3/25 antibodies that are specific for transferrin receptors. About 50% to 80% of the cells were positive for surface membrane immunoglobulin (kappa IgG) and about 10% to 50% for cytoplasmic immunoglobulin (kappa IgG). Virtually all cells were positive when tested for nuclear Epstein-Barr virus antigens.

Adult↗
PubMed1984

ARH-77, an established human IgG-producing myeloma cell line. II. Growth kinetics, clonogenic capacity, chalone production, xenogeneic transplantations, and response to melphalan.

The growth curve of monolayer cultures of ARH-77 cells, a human myeloma cell line propagated in vitro, is represented by an everbending curve on a semilogarithmic plot; however, the curve can be fitted by a straight line on a linear-linear plot. This unusual growth pattern suggests that, instead of a fixed proportion of the population, a fixed number of ARH-77 cells divide per unit time. The following are cell cycle transit time parameters calculated from percent labeled mitosis experiments: TG1, 10.0 +/- 3.5 hours; Ts, 14.3 +/- 2.3 hours; TG2, 4.3 hours; TM, 1.4 +/- 1.3 hours; and Tc, 30.0 +/- 6.1 hours. For cells exposed continuously to 3H-thymidine the values are: growth fraction, 67%; TG1, 6.5 hours; Ts, 13.0 hours; and TG2 + M, 3.0 hours. The average doubling time is 4.6 days (range, 3.8-4.7 days); after about 10 to 15 days in culture, the growth rate of freshly passaged cells declines markedly, as reflected by a growth curve with a much shallower slope. The changes are accompanied by a marked decline in the labeling index from 41.3% (range, 28.9%-53.7%) during the first 3 days of culture to less than 5% measured on day 21. Flow cytometry for DNA content-dependent cell cycle compartment distribution demonstrates an obvious decline in the proportion of S-phase cells and a marked accumulation of G2 phase cells as the cultures age. When the supernatant medium of ARH-77 cells grown for 10 days is replaced by fresh medium, a new burst of vigorous cellular growth is observed with a curve slope similar to that observed during the first 5 days of culture. If the 10-day-old supernatant medium is used to set up cultures with freshly harvested ARH-77 cells, their growth curve resembles that of 10-day-old cultures. However, this supernatant medium induces no decrease in the growth rate of other human tumor cells, suggesting that inhibition of cellular growth does not result from exhaustion of nutrients, but that ARH-77 cells produce a molecular mediator that specifically inhibits the growth of these cells. ARH-77 cells could be synchronized with a single treatment of 3 or 5 mM thymidine; (dThd) and cloning efficiency was 2% to 4% in a double-layer soft agar assay. Treatment for 1 hour with increasing concentrations of melphalan produced a threshold exponential survival curve (Dq = 0.45 microgram/ml and D0 = 0.35 microgram/ml, 1 hour).(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1984

Evidence for extensive intermolecular disulfide bonds of the proteins of non-ionic detergent high-salt-resistant skeletons of normal lymphocytes, and the altered structure in leukemia.

Normal and leukemic lymphocytes were subjected to lysis with a non-ionic detergent and 2.0 M NaCl. The intact nuclear DNA and the associated molecules resulting from these lyses (the nucleoids) were then separated from DNA-dissociated molecules and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Most of the proteins undissociable by 2.0 M NaCl from normal lymphocyte nuclear DNA or from DNA-associated molecules appear to be intermolecularly S-S linked. A distinct set of these proteins was either absent or only present in greatly decreased amounts in association with the leukemic lymphocyte nuclear DNA exposed to 2.0 M NaCl. On the other hand, the opposite relationship was found for a an MW 71,000 protein with leukemic lymphocytes of every patient studied regardless of the subtype of leukemia. Conversion of normal quiescent lymphocytes to cycling cells by lectin stimulation rendered them similar to leukemic cells in some respects but not in all. Our results show an altered nuclo(cyto)skeletal structure in leukemic cells; in general the proteins involved appear to be sulfhydryl proteins whose redox states and/or DNA association properties are modified by the neoplastic transformation of lymphocytes.

Blood Proteins↗
PubMed1984

Dose-survival curves of cis-platinum, melphalan, and velban in human granulocyte/macrophage progenitor cells.

To optimize the in vitro concentrations of anticancer agents with clinical dose-limiting myelosuppression in the human tumor stem cell assay, we established dose-survival curves for cis-platinum, melphalan, and velban in normal human granulocyte/macrophage colony-forming units (CFU-gm) in a bilayer agar system. The LD50 (drug concentration capable of killing 50% of CFU-gm) of cis-platinum, melphalan, and velban for one-hour exposure was (a) greater than 10 micrograms/ml, (b) 0.9 microgram/ml, and 1.2 micrograms/ml, respectively. The respective values for continuous exposure were 0.3 microgram/ml, 0.12 microgram/ml, and 0.001 microgram/ml. The use of dose ranges based on bone marrow tolerance may influence the clinical value of in vitro tumor sensitivity studies of drugs with hematologic toxicity.

Antineoplastic Agents↗
PubMed1984

Responses of human bone marrow progenitor cells to fluoro-ara-AMP, homoharringtonine, and elliptinium.

The cytotoxicity of the investigational anticancer drugs fluoro-ara-AMP, homoharringtonine, and elliptinium on normal human granulocyte-macrophage colony-forming units in culture (GM-CFU) was investigated using a bilayer soft agar system. For each drug, the dose-dependent survival curve on a semilogarithmic plot formed a straight line. The D0 were: 0.51 microgram/ml (fluoro-ara-AMP), 0.004 microgram/ml (homoharringtonine) and 0.026 microgram/ml (elliptinium). The in vitro toxicity of drugs on bone marrow progenitor cells did not correlate with the relative myelosuppressive potency observed in vivo.

Alkaloids↗
PubMed1984

Effect of thymidine on the toxicity and antitumor activity of cis-diamminedichloroplatinum (II).

The effect of thymidine (TdR) on the preclinical toxicity of cis-diamminedichloroplatinum (II) (DDP) was investigated in the BDF1 mouse and the Sprague-Dawley rat. The effect of TdR on the antitumor activity of DDP was investigated using the ascites P388 murine leukemia model. TdR at 500 mg/kg consistently decreased the recovery of body weight after DDP treatment IP, but did not affect the lethal toxicity of DDP to non-tumor-bearing mice or those with the P388 murine leukemia. This effect was greatest when TdR was injected 30 min prior to DDP and at higher doses of DDP. A 500-mg/kg dose of TdR did not affect the antitumor activity of DDP 5 mg/kg administered on days 1, 5, and 9. Treatment of rats with TdR 500 mg/kg according to various schedules of timing relative to a 5-mg/kg dose of DDP did not consistently affect the DDP-related loss in body weight or nephrotoxicity at day 3. Pretreatment of mice with TdR 1,500 mg/kg 30 min prior to DDP 5 mg/kg (every 4 days X 3) resulted in a slower recovery of body weight, which became more pronounced with increasing doses of DDP. Pretreatment of ascites P388-bearing mice with TdR 1,500 mg/kg increased the number of early deaths when mice were treated with DDP 5 mg/kg (days 1, 5, and 9). These data suggest that the cytotoxicity of DDP is increased by TdR only at higher doses of either drug, but that the antitumor activity against P388 murine leukemia is not affected.

Animals↗
PubMed1984

Cultured human tumour cells may be arrested in all stages of the cycle during stationary phase: demonstration of quiescent cells in G1, S and G2 phase.

Six human colon carcinoma cell lines were induced to enter stationary phase of growth by nutrient deprivation and cell crowding. Growth kinetics parameters (cell number, flow cytometric analysis of DNA distribution, and labelling and mitotic indices) were measured sequentially for all lines during the various stages of in vitro growth. Our results demonstrated that a substantial fraction of cells (9-18%) were located in G2 phase when they changed from an exponential to a stationary mode of growth. Moreover, a large number of cells in stationary phase of growth had an S-phase DNA content, as determined by flow cytometry, but failed to incorporate radioactive DNA precursors (up to 15-fold difference). To substantiate these findings, cells in stationary phase of growth were induced to enter exponential growth by re-seeding in fresh medium at a lower density. Subsequently observed changes in DNA-compartment distribution, and in labelling and mitotic indices were those expected from cells that had been arrested at different stages of the cycle during their previous stationary phase. Thus, the non-proliferating quiescent state (Q), traditionally located 'somewhere' in G1 phase, appears to be composed also of cells that can be arrested at other stages of the cycle (Qs and QG2). Although the proportion of such cells is rather small, their contribution to the growth kinetics behaviour of human in vivo tumours will become apparent following 'recruiting' or 'synchronizing' clinical manoeuvres and will prevent the formation of a clear-cut wave of synchronized cells.

Cell Cycle↗
PubMed1984

The true predictive value of the human tumor stem cell assay: does a workable assay select for treatment responders?

In practice, the human tumor clonogenic assay is workable for less than half of the patient population to which it is applied, since the remainder of the specimens fail to produce sufficient numbers of colonies. Thereby a bias may be introduced which could result in a false predictive value positive of the test. It is therefore necessary to compare the responses to treatment of patients whose tumors could be assayed in vitro to those whose tumors failed to grow adequately, to assure that the prevalence of treatment responders has not changed within the group of patients for which the assay worked. From an analysis of the treatment response of 70 patients with stage III and IV ovarian carcinomas and 70 patients with stage IV breast cancer, no selection bias did occur and no preferential in vitro growth of tumor samples from patients with treatment response was found.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1984

Cellular discriminants for a biological classification of human colon carcinoma.

We categorized established human colon carcinoma cell lines into three biological groups. Our studies were performed on six colorectal cancer lines representing the proposed three groups. Group I consisted of two lines designated LoVo and SW 48; Group II comprised two lines called SW 480 and SW 620; and Group III was represented by lines SW 403 and SW 1116. Group I consisted of the most differentiated cells. This differentiation encompassed morphological markers, gland and signet ring formation, and ciliary development. The outstanding morphological characteristic of Group III was the development of numerous multinucleated giant cells. The range and modal chromosome number increased from Group I to Group III, a change reflected by the higher DNA content of these cells as measured by flow cytometry. Carcinoembryonic antigen synthesis was maximal for Group III and virtually absent for Group II. The number of clonogenic cells decreased from Group I to Group III, while the proportion of nonproliferating cells calculated both by experiments using continuous labeling with tritiated thymidine, and by the primer-available alpha-DNA polymerase index, increased from Group I through Group III. Another important cytokinetic difference was that Group I had an exponential cell cycle stage distribution not seen for the other groups. Cells in Group I were easily propagated in athymic (nude) rats by s.c. injection; cells in Group II injected s.c. grew for about 30 days and then regressed spontaneously. Cells in Group III could only be grown when inoculated intracerebrally. Thus, our studies have now confirmed and extended the hypothesis that cultured human colorectal carcinomas can be separated into at least three groups on the basis of morphological differentiation, chromatin distribution, carcinoembryonic antigen production, cytokinetic properties, and xenograft propagation. Perhaps this classification is just the tip of the iceberg, and future studies will determine the existence of additional groups or subgroups on the basis of other markers. However, at present it appears established that malignant cells with a common histological origin in the gut express their phenotypic potential in a sufficiently discrete manner as to permit their classification into distinct biological groups. Thus, the stage is set for extrapolating this in vitro classification for an in vivo segregation of human colorectal tumors into categories with specific properties and diverse prognosis.

Animals↗
PubMed1984

Normalization of in vitro sensitivity testing of human tumor clonogenic cells.

The use of normal bone marrow (granulocyte-macrophage colony-forming units) as a point of reference to normalize the in vitro activities of anticancer agents has been investigated. The cytotoxic effects of four substituted anthraquinone derivatives, and of vinblastine on myeloid progenitors of different donors were reproducible up to a cell kill of approximately 60%. Equitoxic in vitro concentrations for normal bone marrows did not correlate with in vivo pharmacokinetic concentrations of these drugs. Breast tumor progenitor cells of 46 specimens were more sensitive than were bone marrow progenitors to the anthraquinone derivatives in 26 to 39% of instances, ratios which are similar to the clinically observed response rates of patients with breast carcinoma to these agents. Tumors were either sensitive or resistant to all four drugs in 68% (10 tumors were more sensitive, and 21 tumors were less sensitive than normal bone marrow); but in 32% of instances there were differences in tumor sensitivity for the four drugs, and the assay could select one to three drugs for which the tumor sensitivity was greater than that of bone marrow. Correlations of in vitro sensitivity and of clinical response to single agent treatments were determined in 21 patients, and the concordance was 71%. The value of the assay in predicting clinical response ranked best for sensitivity determinations within the normalized dose ranges, when testing within three different dose ranges was compared in a group of six patients. The concordance was higher in the small (1 or 2 metastatic sites) than in the large (greater than or equal to 3 metastatic sites) tumors (85 versus 50%), indicating a confounding influence of tumor load on the ability of the assay to predict efficacy of treatment. A rule of thumb is proposed for altering the in vitro sensitivity test results for large tumors that improves the overall concordance to 90%.

Antineoplastic Agents↗
PubMed1983

The lethal activity and repair inhibition capacity of 1-(2-chloroethyl)-3-(2,6-dioxo-3-piperidyl)-1-nitrosourea (NSC 95466, PCNU), a nitrosourea with low carbamoylating activity.

The survival response of human colorectal carcinoma cells treated in vitro for 1 h with PCNU was characterized by a threshold exponential curve, Dq = 8 micrograms/ml (1 h) and Do = 22 micrograms/ml (1 h). Continuous treatment induced decreasing degrees of cell kill although PCNU was biologically stable in solution for at least 24 h. Cells treated with PCNU were unable to recover from potentially lethal damage but were quite capable of repairing PCNU-induced sublethal damage. Thus, PCNU with different alkylating and carbamoylating than other nitrosourea congeners had similar cytotoxic and repair inhibition capacities. Any therapeutic gain in the clinical use of PCNU must derive only from its lipophilic properties and not from its superior activity at the cellular level.

Antineoplastic Agents↗
PubMed1983

Marrow cytometry and prognosis in myeloma.

We have previously shown that flow cytometric analysis of acridine orange-stained bone marrow cells is useful for the objective enumeration and characterization of plasma cells from patients with myeloma, frequently exhibiting an abnormal DNA and an elevated RNA content. In this report on 77 previously untreated patients, we have investigated the biologic and prognostic implications of these quantitative tumor cell parameters. The degree of marrow involvement by tumor, both by microscopic and cytometric analysis, correlated with the clinically derived tumor mass stage. Examination of the product of relative tumor cell RNA content and marrow tumor infiltrate (as a measure of metabolic capacity for immunoglobulin production) in relationship to the myeloma protein concentration in the serum revealed differences in the efficiency of immunoglobulin production and/or catabolism. There was an inverse relationship between the degree of marrow tumor involvement and RNA index, suggesting a more aggressive behavior of myeloma in patients with a low tumor cell RNA content. Prognostically, high tumor cell RNA content identified patients with a high likelihood of response to both initial treatment (32 patients, P = 0.004) and salvage therapy (29 patients, P = 0.01). Favorable factors for survival were low clinical tumor mass stage (P = 0.07) and low marrow tumor infiltrate as determined morphologically (P = 0.04) and cytometrically (P = 0.004). Thus, the direct examination of marrow cellular DNA and RNA content permitted assessment of tumor burden and was useful in the prediction of response and survival.

Bone Marrow↗
PubMed1983

Effect of diethylaminoethyl-dextran on colony formation of human tumor cells in semisolid suspension cultures.

The effect of diethylaminoethyl-dextran on colony formation of established and primary human ovarian and breast tumor cells in semisolid suspension cultures was investigated. At the concentration of 250 to 300 micrograms/ml used in the human tumor stem cell assay, diethylaminoethyl-dextran inhibited in vitro growth of 3 of 4 human breast tumor cell lines and of 10 of 19 primary tumors. It did not affect growth in 7 primary tumors and enhanced colony formation in 2 tumors. We suggest that diethylaminoethyl-dextran may interact in the human tumor stem cell assay with other sites additional to sulfuric acid residues of the agar and that these effects may cancel or outweigh its purported beneficial effects.

Breast Neoplasms↗
PubMed1983

Potentiation of DNA-reactive antineoplastic agents and protection against S-phase-specific agents by anguidine in Chinese hamster ovary cells.

Anguidine, a protein synthesis inhibitor, has been shown to induce a reversible cell cycle arrest in exponentially growing Chinese hamster ovary cells. The effect of pretreatment with anguidine on the cytotoxicity of subsequently administered various chemotherapeutic agents, hyperthermia, and radiation was investigated. We found that anguidine greatly potentiated the cytotoxic activity of cis-dichlorodiammineplatinum(II) and melphalan by abolishing the initial shoulder and steepening the subsequent exponential portion of the survival curves. Bleomycin-induced cell kill was also potentiated by anguidine pretreatment but to a lesser extent. However, anguidine pretreatment did not substantially alter radiation cytotoxicity. In contrast, anguidine markedly reduced the lethal effect of hydroxyurea, 5-fluorouracil, and hyperthermia, three modalities with S-phase activity. To investigate whether both anguidine-induced potentiation and protection of cells by different antitumor agents were due to its induction of complete suspension of cycle traverse, experiments were also conducted with plateau-phase cultures. Whereas anguidine potentiated cis-dichlorodiammineplatinum(II) cytotoxicity in an identical fashion as noted in exponentially growing cells, its protective effect against lethal damage from Adriamycin was absent. Thus, it appears that the two opposite effects of anguidine modification of cell kill by cytotoxic agents (protection and potentiation) come about by two different mechanisms, with cell cycle arrest underlying cytoprotection and the mechanism of synergistic toxicity remaining obscure.

Animals↗