Cross-resistance and combined cytotoxic effects of paclitaxel and cisplatin in bladder cancer cells

PURPOSE

We studied the cross-resistance and combined cytotoxic effects of cisplatin and paclitaxel in bladder cancer cells in vitro.

MATERIALS AND METHODS

The cytotoxicity of the 2 agents alone or in combination were studied in the bladder cancer cell line NTUB1 and the 2 sublines NTUB1/P, which is cisplatin resistant, and NTUB1/T, which is paclitaxel resistant, using the microculture tetrazolium assay. Schedule dependence of the 2-drug combination was assayed using 3 treatment schedules, including 1 concurrent and 2 sequential exposures.

RESULTS

The mean cisplatin concentration plus or minus standard error of the means inhibiting 50% of the growth of NTUB1, NTUB1/P and NTUB1/T was 1.9 +/- 0.19, 19.3 +/- 2.33 and 2.1 +/- 0.15 microM., respectively, and the mean paclitaxel concentration inhibiting 50% of the growth of the 3 cell lines was 30 +/- 3.9, 1,033 +/- 120 and 110 +/- 15 nM., respectively. NTUB1/P had strong cross-resistance to paclitaxel. In contrast, NTUB1/T was as sensitive as NTUB1 to cisplatin. On median effect analysis the combined effects of the 2 agents given concurrently were sub-additive in the low fraction affected range of 0.1 to 0.3 and additive in the median to high fraction affected range of 0.4 to 1.0 in the 3 cell lines. Combined cytotoxicity was more synergistic when paclitaxel was given 24 hours earlier than cisplatin. The effects were less synergistic when cisplatin was given before paclitaxel. This phenomenon was noted in sensitive and resistant cells.

CONCLUSIONS

In our bladder cancer cell model cisplatin resistant cells have strong cross-resistance to paclitaxel, whereas paclitaxel resistant cells are sensitive to cisplatin. The combined effects may be optimized by sequential use of the 2 agents, preferably paclitaxel given 24 hours before cisplatin. Our results have clinical implications for the treatment of bladder cancer.

Mutagenicity in Salmonella typhimurium of N-3-methylbutyl-N-1-methyl-acetonyl-nitrosamine and N-methyl-N-benzylnitrosamine, N-nitrosation products isolated from corn-bread contaminated with commonly occurring moulds in linshien county, a high incidence area for oesophageal cancer in Northern China

Two synthetic N-nitrosamines (N-3-methylbutyl-N-1-methyl acetonylnitrosamine and N-methyl-N-benzylnitrosamine), previously isolated from corn-bread which had been inoculated with moulds occurring in Linshien county, Northern China and subsequent nitrosation by sodium nitrite, were tested in Salmonella typhimurium strains TA1535 and TA100 in the presence of a liver postmitochondrial supernatant from Aroclor-treated rats. A concentration-dependent increase in the number of mutant colonies in both bacterial strains was observed when N-3-methylbutyl-N-1-methylacetonyl-nitrosamine was assayed in liquid suspension and N-methyl-N-benzylnitrosamine in plate incorporation assays. Our finding that mutagenic N-nitrosamines are present in foodstuffs that may be consumed in Linshien county are discussed in relation to the possible etiological role of these compounds in cancer of the oesophagus in that area.

Placement matching: challenges and technical progress

Although it is highly desirable, standardized placement matching for substance use disorders poses challenges due to variability in settings, services, and syndromes; multidimensionality of clinical problems; multiplicity of outcome constructs; and temporal phenomena in the course of recovery. Despite these obstacles, progress is being made in developing patient placement criteria that are comprehensive with adequate reliability, feasibility, and resolution. With these methodological advances, it has been possible to initiate controlled research with placement criteria. The first such studies provide early evidence supporting such criteria and indicate areas for refinement.

Characterization of chemoresistance mechanisms in a series of cisplatin-resistant transitional carcinoma cell lines

We explored the mechanisms of cisplatin resistance in a series of bladder transitional carcinoma cells that are either sensitive or progressively resistant to cisplatin. Resistant lines were raised by chronic exposure of the parental cells to progressively increased concentrations of cisplatin. The cisplatin IC50s of the sensitive and the three resistant cells were 4.3, 25.0, 40.4, and 52.2 microM, respectively. The expressions of glutathione S-transferase pi (GST-pi) and multidrug resistance-associated protein (MRP) were enhanced in a dose-response manner as cells acquired progressive cisplatin resistance. Expression of mdr-1 transcript was detected in the three resistant lines but not in the sensitive line. Glutathione contents were increased in resistant cells, yet the trend of increase did not reach statistical significance (p = 0.061). In conclusion, transitional carcinoma cells may gain cisplatin resistance through multiple pathways including up-regulation of GST-pi, MRP and possibly mdr-1. Glutathione contents may play a less significant role in cisplatin chemoresistance.

Mitochondrial DNA deletion of the human detrusor after partial bladder outlet obstruction-correlation with urodynamic analysis

OBJECTIVES

To investigate mitochondrial DNA (mtDNA) mutations in human detrusor after partial bladder outlet obstruction (BOO) and correlate the findings with the results of urodynamic studies.

METHODS

Sixty-two male patients with and without BOO were recruited and assessed by the International Prostate Symptom Score, a quality-of-life assessment index, and sonography. The severity of partial BOO was determined by pressure-flow study with an International Continence Society (ICS) nomogram. Random detrusor biopsies obtained cystoscopically were analyzed by polymerase chain reaction (PCR) techniques to detect possible mtDNA deletions. Primer-shift PCR and DNA sequencing were then performed to characterize specific mtDNA deletions. A semiquantitative PCR method was used to determine the proportion of the deleted mtDNA in detrusor. Finally, the mtDNA deletion and the urodynamic results were compared statistically.

RESULTS

A 4977-bp mtDNA deletion was identified in the human detrusor. Its incidence and proportion were found to increase after partial BOO (P = 0.005 and 0.012, respectively). The incidence of the mtDNA deletion was 4.2% (1 of 24) in the unobstructed group, 27.8% (5 of 18) in the equivocal group, and 40% (8 of 20) in the obstructed group. The mean proportion of the 4977-bp deleted mtDNA was 23.7 and 12.7 times higher in the obstructed and equivocal groups, respectively, compared with that of the unobstructed group.

CONCLUSIONS

We found mtDNA with the 4977-bp deletion in human detrusor and an increase of this deletion after partial BOO. This molecular change might account for the previous observations of mitochondrial functional impairment and voiding dysfunction after partial BOO.

Morphological and morphometric analysis of human detrusor mitochondria with urodynamic correlation after partial bladder outlet obstruction

PURPOSE

We correlated ultrastructural changes in mitochondria in the human detrusor with the severity of partial bladder outlet obstruction on urodynamics.

MATERIALS AND METHODS

We recruited into the study 52 men with and without bladder outlet obstruction symptoms. The severity of partial bladder outlet obstruction was determined by pressure flow study. Random detrusor biopsy specimens obtained by cystoscopy were fixed immediately and processed for transmission electron microscopic observation. Random areas were photographed for further morphological and morphometric analysis using mitochondrial damage score and stereological principles.

RESULTS

Mitochondrial damage score and mean mitochondrial volume strongly correlated with the urodynamic severity of partial bladder outlet obstruction, while mitochondrial volume density, surface density of the mitochondrial outer membrane and number of mitochondria per unit of cytoplasm area did not significantly correlate with severity.

CONCLUSIONS

Detrusor mitochondrial swelling and structural destruction increased with the severity of partial bladder outlet obstruction. These changes may be associated with impaired mitochondrial function and oxidative metabolism after partial bladder outlet obstruction. Detrusor mitochondrial damage may explain voiding dysfunction after partial bladder outlet obstruction develops.

Mifepristone regulation of leukemia inhibitory factor and uterine receptivity in rabbits

The effects of mifepristone on production of leukemia inhibitory factor (LIF) and uterine receptivity in rabbits was studied. In ovariectomized rabbits, LIF protein was at an undetectable level in control (score = 0), and upregulated by progesterone alone (score = 4). Estrogen had no additive effect, and may even have had a slightly negative effect when the rabbits were treated with both estrogen and progesterone (score = 3). Meanwhile, mifepristone obviously inhibited the stimulation of progesterone on the production of LIF in rabbit uterus (score = 1). The results also showed that LIF protein has a beneficial effect on uterine receptivity and mifepristone prevents this effect. The transfer of embryos to LIF-treated recipients significantly increased pregnancy (70%) and implantation rate (31%) as compared with control (pregnant rate = 50% and implantation rate = 17%). The transfer of embryos to LIF and mifepristone-treated recipients significantly decreased pregnancy (30%) and implantation rate (9%). The results of this study suggest that mifepristone prevented the effects of progesterone on LIF production and the beneficial effect of LIF on uterine receptivity.

Megestrol acetate antagonizes cisplatin cytotoxicity

Megestrol acetate (MGA) is being widely used for the improvement of appetite and performance status in patients receiving chemotherapy, especially cisplatin-containing therapy. However, little is known about whether MGA has an effect on cisplatin cytotoxicity. We have investigated this using two transitional carcinoma cell lines, i.e. the cisplatin-sensitive parental line NTUB1 and the resistant daughter line NTUB1/P. Combined effects of MGA and cisplatin were assayed with a microculture chemosensitivity method. We explored the level changes of several cisplatin detoxification mechanisms, including metallothionein (MT), glutathione S-transferase-pi (GST-pi) and glutathione (GSH) levels in cells treated with or without MGA. After treatment with 10 microns MGA for 24 h, the cisplatin IC50s of NTUB1 and NTUB1/P increased 1.4- (p = 0.03) and 1.6- (p = 0.02) fold, respectively. By median effect analysis, the combinations of MGA and cisplatin in the two cells appeared to produce an antagonistic interaction. By Northern analysis, MT transcript levels in both cells were significantly upregulated after treatment with MGA, as compared to those without treatment. Exposure to MGA in either sensitive or resistant cells did not alter GST-pi levels as shown by immunoblotting analysis. Cellular GSH content was increased only in NTUB1/P (p = 0.0036) but remained unchanged in NTUB1 cells (p = 0.29) after MGA exposure. In conclusion, MGA may antagonize cisplatin cytotoxicity by upregulating cellular MT and GSH levels. Use of MGA in cisplatin-containing chemotherapy may impair tumor response by antagonizing cisplatin antitumor activity.

Economic reforms and the acute inpatient care of patients with schizophrenia: the Chinese experience

OBJECTIVE

This study compared insured and uninsured schizophrenic inpatients in China and examined changes in the acute inpatient care of schizophrenic patients during China's economic reform era.

METHOD

Detailed chart reviews of 50 randomly selected inpatients discharged from a hospital in central China each year from 1984 through 1993 identified 321 patients with schizophrenia. Demographic, insurance, treatment, and cost data of these patients were collected from the charts.

RESULTS

With logistic regression models to control for confounding variables, the analyses showed that the 129 insured patients were significantly more likely than the 192 uninsured patients to be urban residents, to be older, to have had 7 or more years of schooling, and to have had more psychiatric hospitalizations; moreover, their index admissions were longer and were more likely to include use of traditional Chinese medications. The estimated 19% of schizophrenic individuals in the community with health insurance receive inpatient treatment 2.8 times more frequently than the 81% without insurance. Compared to admissions in 1984-1988, admissions in 1989-1993 were significantly shorter and involved longer periods of polypharmacy with multiple antipsychotic medications but included lower mean chlorpromazine-equivalent doses of medication. The relative cost of inpatient care for an acute episode of schizophrenia increased 3.5-fold over the 10-year period, from 11% of mean annual household income in 1984 to 37% in 1993.

CONCLUSIONS

Changes in the incentive system for care providers and rapid increases in the cost of care during the economic reform era have resulted in increasingly restricted availability of services for the many schizophrenic patients without health insurance.

Non-small cell lung cancer with testicular metastasis: a case report

A 51-year-old man was diagnosed to have non-small cell lung cancer, right middle lobe, with multiple bony metastasis. Systemic chemotherapy with the regimens of cisplatin plus etoposide was administered. A 2 x 2.5 cm firm nodule in the right testis was incidentally found two weeks after the first course of chemotherapy. Transinguinal right radical orchiectomy was performed. Pathologic examination revealed a picture similar to his lung cancer. Secondary carcinoma of the testis is extremely rare. The relevant literature about its incidence, clinical manifestations, sources of primary tumor and routes of metastasis are reviewed.

p53 mutations in esophageal tumors from high-incidence areas of China

Carcinomas of the upper digestive tract (squamous-cell carcinoma of the esophagus, adenocarcinoma of the cardia) from 24 patients residing in Linxian (China) and near-by high-incidence areas were analyzed for mutations in exons 5-8 of the p53 tumor-suppressor gene. Mutations were identified by polymerase chain reaction amplification and direct sequencing in 50% of the specimens. Eleven tumors harbored a single base-pair substitution leading to either an amino-acid substitution (8 tumors) or a chain-termination signal (3 tumors), and one tumor revealed a 15-bp deletion in exon 7 with a silent base substitution adjacent to the deletion site. Mutations occurred in all 4 exons examined, with a preponderance in exon 5. Of the 6 mutations identified among the 14 adenocarcinomas examined, 3 were G to T transversions, a mutation that has thus far been absent from reported mutations in Barrett's esophageal adenocarcinomas and dysplasias from patients residing in Europe and North America.

Volatile N-nitrosamines and their precursors in Chinese salted fish--a possible etological factor for NPC in china

Epidemiological studies show that the consumption of Chinese salted fish is a causative factor for nasopharyngeal carcinoma (NPC) in southern China. In the present study, N-nitrosamines and their precursors were analyzed in 145 samples of cooked, salted fish collected from various areas in China. The results show that N-dimethylnitrosamine (NDMA), N-diethylnitrosamine (NDEA), N-nitrosopyrrolidine (NPYR) and N-nitrosopiperidine (NPIP) were present in the salted fish. Total volatile N-nitrosamines (TVN) in the salted fish were 0.028 to 4.54 mg/kg. The samples from areas with higher NPC risk showed a higher average level of TVN than those from areas of lower NPC risk. Positive correlations were found between the levels of NDMA, NDEA and TVN and mortality from NPC. Although neither the nitrates nor the nitrites in the salted fish were present at significantly high levels, in vitro data regarding nitrosation of salted fish showed that the N-nitrosamine content had increased substantially. The results support the conclusion that the high NPC risk in southern Chinese may be attributed to consumption of salted fish containing high levels of N-nitrosamines.

Altered expression of the cyclin D1 and retinoblastoma genes in human esophageal cancer

We have examined DNA from four human esophageal carcinoma cell lines and 50 primary esophageal carcinomas obtained from China, Italy, and France for amplification of the cyclin D1 gene. We also examined 36 of these 50 carcinomas for expression of the cyclin D1 and retinoblastoma (RB) proteins by immunohistochemistry. We found a 3- to 10-fold amplification of the cyclin D1 gene in 16 of the 50 (32%) tumors and in two of the four cell lines. Cyclin D1 protein was overexpressed in 12 of 13 tumors and the two cell lines that showed gene amplification when compared to normal controls. Studies on RB protein expression indicated that 6 of the 36 (17%) tumor samples examined and one cell line did not show detectable expression of this protein. The tumors and cell lines that had cyclin D1 gene amplification and overexpression exhibited normal levels of expression of RB protein. By contrast, the tumors and cell line that did not appear to express the RB protein did not show amplification of the cyclin D1 gene and expressed only low levels of the cyclin D1 protein (P = 0.03). These results suggest that the inhibitory effect of RB on cell cycle progression can be abrogated during tumor development either by loss of expression of the RB gene or by increased expression of the cyclin D1 gene.

Inhibitory effect of interferon and tumor necrosis factor on human luteal function in vitro

OBJECTIVE

To investigate whether immunological mechanisms may be involved in human luteal function.

DESIGN

The effects of the cytokines, interferon-alpha (IFN-alpha), interferon-gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) on steroidogenesis by human luteal cells were examined in vitro. The dispersed human luteal cells, obtained from a total of 17 women at laparotomy, were cultured separately in the presence or absence of human chorionic gonadotropin (hCG) and IFNs/TNF-alpha with the medium being replaced at 48 hours. The medium was collected at 48 and 96 hours for steroid assays.

RESULTS

The IFN-alpha had no significant effect on the production of estradiol or progesterone (P), whereas a dose-related inhibition of basal, as well as hCG-stimulated P formation, was observed after the addition of IFN-gamma (10 to 1,000 U/mL). Progesterone production was inhibited to about 45% of the control at 48 hours and even lower at 96 hours (n = 6, P < 0.001). The combination of IFN-gamma and low doses of TNF-alpha induced a further significant inhibition, whereas there was no effect of TNF-alpha alone. This inhibitory effect of IFN-gamma could be completely neutralized with a monoclonal antibody to IFN-gamma. Incubation with the antibody alone increased the production of P from luteal cells in culture, suggesting a local tonic inhibitory action of endogenous IFN-gamma.

CONCLUSION

Interferon-gamma and TNF-alpha, whose function classically is known as antiviral, also may play a role in human luteal regression by inhibiting luteal P production.

Amplification and expression of the human cyclin D gene in esophageal cancer

Amplification of the hst-1 and int-2 genes on chromosome 11q13 has previously been found in over 20% of human primary esophageal cancers. However, these two genes do not appear to be transcribed in appreciable amounts. Recently, the human cyclin D gene (also referred to as prad1) has been mapped to the 11q13 locus. Here, we report coamplification of the cyclin D and hst-1 genes in 5 of 20 (25%) human squamous esophageal tumors. We also detected significant levels of cyclin D transcription in two esophageal carcinoma cell lines, even though they did not express detectable amounts of hst-1 transcription. These findings provide the first evidence for the amplification of a cyclin gene in human esophageal cancer and suggest that an increase in cyclin D gene dosage could be an important factor in the pathogenesis of esophageal cancer. Additionally, because the 11q13 locus is found to be amplified in many types of human tumors, cyclin gene amplification could also play an important role in the development of other forms of human cancer.

Control of inhibin production by dispersed human luteal cells in vitro

The production of inhibin in vitro by dispersed cells from early to mid (Days 16-19) and late stage (Day 23) human corpus luteum (CL) was examined, and the effects of human chorionic gonadotrophin (hCG), follicle stimulating hormone (FSH), oestradiol and testosterone on inhibin production were determined. Corpora lutea from five subjects in the early to mid luteal stage and three subjects in late luteal stage were dispersed with enzymes and the luteal cells cultured in medium supplemented with 5% calf serum and either FSH (1, 10 or 100 ng mL-1), oestradiol-17 beta (2.5, 5 or 10 micrograms mL-1) or testosterone (0.25, 1 or 5 micrograms mL-1) with or without hCG (1 I.U. mL-1). Cells were cultured for 1 to 3 days without changes of medium, and the concentrations of progesterone, oestradiol and immunoreactive inhibin in the medium were measured by radioimmunoassay. Cells from both types of CL produced inhibin in vitro under basal conditions, but only cells from early to mid CLs responded to hCG with a significant increase in inhibin production. Both progesterone and oestradiol production were stimulated by hCG in both groups of CL. Inhibin concentrations in the cell cultures declined with time in culture, particularly in the late CL group, whereas the concentration of steroids increased. Neither FSH, oestradiol nor testosterone significantly changed inhibin production in either CL group. It was concluded that inhibin production by human luteal cells in vitro is influenced by the age of the CL, and is dependent on LH (hCG) but not on FSH or sex steroids.

Rapid detection of ras oncogenes in human tumors: applications to colon, esophageal, and gastric cancer

We have developed a rapid, nonradioactive large scale method for the detection of ras oncogenes in human tumors. DNA is amplified by the polymerase chain reaction (PCR), and then digested with specific restriction enzymes to detect either endogenous or primer-mediated Restriction Fragment Length Polymorphisms (RFLPs). We report here that three of 15 colon tumors tested contain K-ras codon 12 aspartic acid mutations and one, along with the HCT 116 colon carcinoma cell line, contains a K-ras codon 13 aspartic acid mutation. On the other hand, we did not detect H- or K-ras codon 12 mutations or the K-ras codon 13 aspartic acid mutation in 25 esophageal and 27 gastric cardia tumors isolated from patients in Lin-xing County, China. By incorporating nucleotide substitutions in PCR primers, this method can be applied towards the rapid, non-radioactive screening of virtually any genetic disease caused by known point mutations.

A study of sex identification of trace, dried bloodstains using a Y-chromosome-specific deoxyribonucleic acid (DNA) probe

A new method is discussed which examines trace, dried bloodstains by gel in situ hybridization using a Y-chromosome-specific deoxyribonucleic acid (DNA) probe to determine the sex of the bloodstain for forensic medicine application. The complete DNA is transferred directly by electrophoresis onto the gel intact, bypassing the possibilities of impurities contaminating the sample and of DNA degradation. The method has proven accurate for small (2.5-mm-diameter) samples aged up to eight years and is quick, simple, and easily read.