Biomedical subjects

S K Banerjee

Publications and source records attributed to S K Banerjee.

At least 37 records · Page 2Linked to original sources

PubMed2001

Differential expression of WISP-1 and WISP-2 genes in normal and transformed human breast cell lines.

The transcriptional alterations of specific gene(s) are actively associated with the development of different cancers including breast. The preceding studies of different laboratories documented at least 40 genes that may contribute directly to the genesis of cancer. Using differential display, RT-PCR and DNA sequencing analyses in normal human mammary epithelial cells (HMEC) and various breast tumor cell lines including MCF-7, ZR-75, T-47D and SKBR2, we demonstrated that WISP-1 and WISP-2 genes are differentially transcribed in these cells. WISP-2 mRNA transcription was identified in all 4 tumor derived cell lines, but the mRNA expression was undetected or minimally detected in normal breast epithelial cells. WISP-1 mRNA expression was identified in normal and transformed cell lines. However, the level of expression was higher in different breast tumor cell lines as compared to HMEC. The mRNA expression profiles of WISP genes in normal breast epithelial cells and breast tumor derived cell lines indicated a strong possibility of the involvement of WISP-signaling in the development of human breast tumors, and can be utilized as genetic markers of this disease.

Base Sequence↗

PubMed2001

p53 protein overexpression in low grade dysplasia (LGD) in Barrett's esophagus: immunohistochemical marker predictive of progression.

OBJECTIVES: The presence of low grade dysplasia (LGD) within Barrett's esophagus (BE) has a multitude of ramifications. Identification of markers that could risk stratify LGD would be of great clinical benefit. We aimed to prospectively evaluate the prognosis of the immunohistochemical overexpression of p53 protein in BE colocalized to LGD. METHODS: Consecutive BE patients in whom LGD was found had a repeat esophagogastroduodenoscopy within 8-12 wk per an ongoing prospective study. At each esophagogastroduodenoscopy, a therapeutic scope was used in conjunction with the Seattle Biopsy Protocol. Patients were observed until development of multifocal high grade dysplasia (mHGD), presence of an HGD dysplasia-associated lesion or mass (DALM) lesion, or frank adenocarcinoma. p53 protein overexpression was determined by computerized immunoquantitation using image analysis software on step serial-sectioned specimens of BE segment(s) harboring LGD. Kaplan-Meier survival curves were made on the ability of p53 staining colocalized to areas of LGD to predict progression to mHGD, HGD DALM, or cancer during prospective follow-up. RESULTS: Forty-eight BE patients with LGD were observed for a mean of 41.2+/-22.5 months. During this period, five of 48 patients progressed to mHGD with a focus in which intramucosal cancer could not be excluded (one), mHGD/DALM with one or more foci in which intramucosal cancer could not be excluded (two), cancer (one), or mHGD (one). Twelve had persistent LGD and 31 had regressed to no dysplasia. p53 staining was positive and colocalized to areas of LGD in 4/31 of patients that regressed, 3/12 that persisted, and 3/5 that progressed. Kaplan-Meier curves differed significantly between p53 positive and negative patients for outcome defined as progression of LGD. CONCLUSIONS: p53 colocalization with LGD at index LGD diagnosis is a risk factor for progression of LGD. This can potentially be used to risk stratify BE LGD patients in terms of surveillance intervals or enrollment into secondary prevention studies.

Adult↗

PubMed2001

Identification of a new plasmid-encoded sec-dependent bacteriocin produced by Listeria innocua 743.

Listeria innocua 743 produces an inhibitory activity demonstrating broad-spectrum inhibition of Listeria monocytogenes isolates. Gel-electrophoretic analysis of culture supernatants indicated that two inhibitors with different molecular weights were produced by this strain. Insertion of Tn917 into a 2.9 Kb plasmid (pHC743) generated mutants with either an impaired ability or a loss in ability to produce one of the inhibitors. Sequence analysis of the transposon insertion regions revealed the presence of two continuous open reading frames, the first encoding a new pediocin-like bacteriocin (lisA) and the second encoding a protein homologous with genes involved in immunity toward other bacteriocins (lisB). Translation of the bacteriocin gene (lisA) initiates from a noncanonical start codon and encodes a 71-amino-acid prebacteriocin which lacked the double glycine leader peptidase processing site common in other type II bacteriocins. Alignment of the sequence with the processed N termini of related bacteriocins suggests that the mature bacteriocin consists of 43 amino acids, with a predicted molecular mass of 4,484 Da. Mutants containing insertions into lisA were sensitive to the inhibitor, indicating that lisAB forms a single operon and that lisB represents the immunity protein. Cloning of an amplicon containing the lisAB operon into Escherichia coli resulted in expression and export of the bacteriocin. This finding confirms that the phenotype is dependent on the structural and immunity gene only and that export of this bacteriocin is sec dependent. This is the first confirmation of bacteriocin production in a Listeria spp., and it is of interest that this bacteriocin is closely related to the pediocin family of bacteriocins produced by lactic acid bacteria.

Amino Acid Sequence↗

PubMed2001

Identification of genomic imbalances in gastric MALT lymphoma using arbitrarily primed PCR DNA fingerprinting.

Arbitrarily primed PCR (AP-PCR) is a unique method to identify the cancer cell specific losses and gains of chromosomal regions by targeting specific genes or chromosomal segments. In the present study, introducing the AP-PCR technique with a single primer, we have ascertained the gains and losses of DNA fingerprints in 15 MALT lymphoma samples. Out of 15 prominent DNA fingerprints, the signal intensity of two fingerprints, labeled bands G and I, were significantly lower in 40 and 50% of tumors as compared to adjacent normal DNA fingerprints, respectively. Similarly, gains of signal intensity of DNA fingerprints (bands A and C) were detected in 13% of tumor samples studied. Variations in signal intensities were also found in other bands within a few samples. Although, the functional importance of these bands is unknown, this study indicates that the AP-PCR generated under or over amplified DNA fingerprints may participate during the progression of MALT lymphoma in human stomach. Moreover, these studies also suggest that the AP-PCR technique, with different primers, can be utilized for the determination of new chromosomal segments in MALT lymphoma samples that can be used for the identification of these diseases.

Biopsy↗

PubMed2000

Bioavailability of tobramycin after oral delivery in FVB mice using CRL-1605 copolymer, an inhibitor of P-glycoprotein.

Tobramycin is an aminoglycoside used in the treatment of infection against gram-negative bacteria. Tobramycin cannot be delivered orally probably due to efflux of drug by a P-glycoprotein pump in the brush border of the small intestine. In this report we demonstrate oral delivery of tobramycin in FVB mice using CRL-1605 copolymer as a vehicle. This copolymer is known to inhibit P-glycoprotein. Two different doses of tobramycin (25 mg/kg and 200 mg/kg) were used. The concentration of CRL-1605 copolymer was 132 mg/kg. The liquid formulation was fed to mice by gavage and serum tobramycin concentrations were measured after one and two hours using the fluorescence polarization immunoassay. We observed significant increases in serum tobramycin concentrations when the drug was delivered orally with the copolymer compared to when the drug was delivered alone. We also performed a bioassay using Bacillus subtilis to confirm antibacterial effect of tobramycin in mice sera. This was to ensure that tobramycin did not undergo structural change during oral absorption when delivered in the copolymer vehicle. We observed minimal inhibition in growth of Bacillus subtilis in sera obtained from mice fed with tobramycin alone. In contrast, we observed almost complete inhibition of growth (most specimens) in sera obtained from mice fed with tobramycin in the presence of CRL-1605 copolymer. We conclude that tobramycin delivered orally in mice using copolymer 1605 is also bioactive.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2000

Involvement of a natural transport system in the process of efflux-mediated drug resistance in Mycobacterium smegmatis.

The phosphate-specific transporter (Pst) in bacteria is a multi-subunit system which belongs to the ABC family of transporters. The gene forms part of an operon and it is involved in phosphate uptake in prokaryotes. Its import function is known to be operative only under conditions of phosphate starvation. However, we found overexpression of this transporter in a Mycobacterium smegmatis strain selected for ciprofloxacin resistance (CIPr) which was grown under conditions in which the phosphate-scavenging function of this operon was inoperative. In CIPr cells, active efflux of the drug plays a predominant role in conferring high levels of fluoroquinolone resistance. We therefore investigated the role of this transporter in the process of efflux-mediated drug resistance by inactivating the pst operon in the CIPr strain. Phenotypic characterization of the resulting strain, CIPrd, showed a striking reduction in the minimal inhibitory concentration (MIC) of ciprofloxacin and in the drug extrusion profile as well. Genotype analysis, on the other hand, revealed partial disruption of the pst operon in CIPrd as a consequence of transporter gene amplification. Furthermore, disruption of this operon in wild-type cells resulted in hypersensitivity to ciprofloxacin and other xenobiotics to which CIPr cells exhibited cross-resistance. Thus our results provide strong evidence that Pst is a natural membrane transport system that has the ability to promote drug efflux in addition to its phosphate-scavenging function in the CIPr strain.

ATP-Binding Cassette Transporters↗

PubMed2000

Expression of cdc2 and cyclin B1 in Helicobacter pylori-associated gastric MALT and MALT lymphoma : relationship to cell death, proliferation, and transformation.

Mucosa-associated lymphoid tissue (MALT) may accumulate within gastric mucosa as a result of long standing Helicobacter pylori infection, and this acquired MALT may eventually develop into low-grade B-cell MALT lymphoma. To determine the possible association of cell cycle regulatory proteins and apoptotic cell death in the transformation of H. pylori gastritis to MALT lymphoma, the extent of cell proliferation, cell viability, expression of Cdc2/Cdk1 and cyclin B in gastric mucosal from patients with H. pylori-positive chronic gastritis (n = 7), MALT (n = 12), or MALT lymphoma (n = 12) were undertaken. Control tissue was obtained from H. pylori- negative patients (n = 5). Proliferating cell nuclear antigen (PCNA), Cdc2, and cyclin B1 were examined in paraffin embedded tissue by immunohistochemistry, while the apoptotic index (AI) was determined using the TUNEL assay. H&E staining for histology and modified Giemsa staining for the detection of H. pylori was conducted simultaneously. When compared to chronic gastritis tissue, those with MALT or MALT lymphoma had an increase in PCNA labeling index of 3.3- and 2.7-fold, while that for Cdc2/Cdk1 increased 2.3- and 3.1-fold, respectively. cyclin B1 labeling was 1.9 and 3.0 fold, while the AI was 3.4- and 1.4-fold higher in MALT and MALT lymphoma tissue, respectively, in the same comparison. On the other hand, the AI index of MALT lymphoma was 2. 5-fold lower than that for MALT tissues. The labeling scores for Cdc2/Cdk1 and cyclin B1 were significantly higher in the germinal center when compared to the mantle and marginal zones of MALT tissues. Using chi(2) and Pearson/Spearman's rho correlation coefficient with regression analyses, there was an inverse correlation between the AI and Cdc2/Cdk1 or cyclin B1 in MALT and MALT lymphoma tissues. There was no correlation between AI and PCNA labeling in any of the tissues. These results suggest that Cdc2/Cdk1 and cyclin B1 expression may be actively associated in the modulation of cellular death by apoptosis, as well as cellular proliferation and transformation during the evolution of H. pylori-associated gastritis to MALT lymphoma. Subclassification of high labeling score (>/=40) for Cdc2/Cdk1 and cyclin B1 and low labeling index (<0.6) for apoptotic cells in H. pylori-associated MALT may help in identifying a population of patients with an increased risk of developing MALT lymphoma.

Apoptosis↗

PubMed2000

Anti-inflammatory and anti-arthritic activities of silymarin acting through inhibition of 5-lipoxygenase.

Silymarin, a mixture of flavonolignans, comprised mainly of three isomers, silybin, silydianin and silychristin isolated from the fruits of Silybum marianum, is currently in therapeutic use as a hepatoprotective agent. Silymarin on evaluation exhibited significant antiinflammatory and antiarthritic activities in the papaya latex induced model of inflammation and mycobacterial adjuvant induced arthritis in rats. Results of the study indicate its action through inhibition of 5-lipoxygenase for antiinflammatory and antiarthritic activities.

Animals↗

PubMed2000

Evidence that phosphate specific transporter is amplified in a fluoroquinolone resistant Mycobacterium smegmatis.

We reported in an earlier study that active efflux of drug has a predominant role in conferring resistance in a laboratory-generated ciprofloxacin-resistant mutant of Mycobacterium smegmatis. This mutant exhibited mRNA level overexpression, as well as chromosomal amplification, of the gene pstB, encoding the putative ATPase subunit of phosphate specific transport (Pst) system. We demonstrate here that this mutant shows enhanced phosphate uptake and that inactivation of pstB in the parental strain results in loss of high affinity phosphate uptake and hypersensitivity to fluoroquinolones. These findings suggest a novel role of the Pst system in active efflux, in addition to its involvement in phosphate transport.

ATP-Binding Cassette Transporters↗

PubMed2000

Tumor angiogenesis in chronic pancreatitis and pancreatic adenocarcinoma: impact of K-ras mutations.

Chronic pancreatitis (CP) is one condition in which epidemiologic studies have demonstrated a definite association with pancreatic adenocarcinoma (PAC). The pathophysiologic and molecular events that either predispose to the development of, or potentiate the growth of, PAC are unknown. Mutation of the codon 12 K-ras gene is one genetic aberration commonly associated with development of PAC. Tumor angiogenesis, or microvascular proliferation of new capillaries, is another pathophysiologic alteration associated with PAC. Although activated ras oncogenes modulate tumor angiogenesis/neovascularization in some tumors, the importance of tumor angiogenesis and the role of K-ras mutation in regulating angiogenesis in CP and PAC are unknown. The aim of this study was to elucidate the relationship between angiogenesis and K-ras mutations in CP and PAC. Tumor angiogenesis and K-ras mutations were evaluated in resected specimens from 25 CP (23 CP plus two CP with PAC) and 16 PAC patients. Tumor angiogenesis was determined using immunohistochemistry of factor VIII-related antigen (FVIIIRAg) and ras mutations were identified by enriched-nested polymerase chain reaction. The mean number of FVIIIRAg-positive blood vessels was significantly (p < 0.005) higher in PAC (23.0 +/- 7.5), CP with a mutant K-ras genome (17.7 +/- 2.8) and CP with a normal K-ras genome (6.5 +/- 3.8), compared to unaffected areas. Codon 12 K-ras mutations were detected in three of 25 CP specimens (12%) and in 15 of 16 PAC specimens (94%). In CP patients with mutant K-ras in their genome, microvessel density was significantly (p < 0.01) elevated, compared to patients with a normal K-ras genome. Statistical analyses (Spearman rank-difference correlation coefficient, Student t test, and chi2 analysis) indicated a significant association between codon 12 K-ras mutations and tumor angiogenesis in both CP and PAC. This study demonstrates a significant association between angiogenesis and K-ras mutation in both PAC and CP. At a minimum, K-ras mutation is associated with the events that increase angiogenesis and it may potentiate or promote tumor angiogenesis.

Adenocarcinoma↗

PubMed2000

Overexpression of vascular endothelial growth factor164 and its co-receptor neuropilin-1 in estrogen-induced rat pituitary tumors and GH3 rat pituitary tumor cells.

We have shown previously that the VEGF system plays a crucial role in regulation of tumor angiogenesis during the development of estrogen-induced prolactin-secreting pituitary tumors in Fisher 344 rats. Studies also suggested that both endothelial and non-endothelial cells expressed VEGF. However, several questions concerning the VEGF signals in regulation of estrogen-induced angiogenesis in rat pituitary remained unanswered. VEGF exists in a number of isoforms in human and rodent tissue (i.e., VEGF206h/205r, VEGF189h/188r, VEGF165h/164r, VEGF145h/144r and VEGF121) that differ in their molecular masses and biological activities. The VEGF isoforms bind with two tyrosine-kinase receptors, KDR/flk-1 and flt-1. In addition, VEGF165 binds with a newly identified co-receptor, neuropilin-1, which is expressed in human endothelial cells and several types of non-endothelial cells including tumor cells. The present study was undertaken to elucidate which isoforms of VEGF are predominantly expressed in normal Fisher 344 rat pituitaries, estrogen-induced prolactin secreting rat pituitary tumors and in prolactin secreting rat pituitary tumor cell line (GH3 cell line). To identify the isoform, RT-PCR with primer pairs derived from exon 1 and exon 8 of the VEGF gene, cloning, sequencing and Western blot analysis were performed. The status of neuropilin-1 in the rat pituitaries (normal and transformed) and GH3 pituitary tumor cell line has also been investigated using RT-PCR and Western blot analysis. These studies demonstrate that normal rat pituitaries, estrogen-induced rat pituitary tumors and GH3 pituitary tumor cells expressed VEGF164 and co-receptor, neuropilin-1. The VEGF164 was the predominant form in all of these cells. The VEGF164 and neuropilin-1 mRNA and protein levels were significantly higher in the estrogen-induced pituitary tumors and GH3 tumor cell line, as compared to normal pituitary. The data suggest that both VEGF164 and neuropilin-1 may actively participate in modulation of tumor angiogenesis and the development of pituitary tumors in Fisher 344 rats.

Animals↗

PubMed1999

Studies on antidiarrhoeal activity of Punica granatum seed extract in rats.

Methanol extract of Punica granatum seed was evaluated for antidiarrhoeal activity against different experimental models of diarrhoea in rats. P. granatum seed extract treated animals showed significant inhibitory activity against castrol-oil induced diarrhoea and PGE2 induced enteropooling in rats. The extract also showed a significant reduction in gastro-intestinal motility in charcoal meal test in rats. The results obtained established the efficacy of P. granatum seed extract as an antidiarrhoeal agent.

Animals↗

PubMed1999

Overexpression and amplification of c-myc in the Syrian hamster kidney during estrogen carcinogenesis: a probable critical role in neoplastic transformation.

An estrogen receptor-driven, multistep process for estrogen carcinogenesis in the Syrian hamster kidney is proposed. Because in this species the reproductive and urogenital tracts arise from the same embryonic germinal ridge, it is evident that the kidney has carried over genes that are responsive to estrogens. Using in situ hybridization, overexpression of early estrogen-response genes, i.e., c-myc and c-fos, has been shown to be localized preferentially in early renal tumor foci after 3.5-4.0 months of estrogen treatment. This event coincides with an increased number of S-phase proliferating cell nuclear antigen-labeled cells in these tumor foci, along with a rapid rise in aneuploid frequency in the kidney. Western blot analyses of c-MYC and c-FOS protein products support the overexpression of these genes. Amplification of c-myc, 2.4-3.6-fold, but not of c-fos, was detected in 67% of the primary renal tumors examined, by Southern blot analyses. Consistent chromosomal gains, common to both diethylstilbestrol- and estradiol-induced renal neoplasms, were observed in chromosomes 1, 2, 3, (6), 11, (13), 16, 20, and 21 (chromosome number alterations are indicated in parentheses). Using fluorescence in situ hybridization, the c-myc gene was localized to hamster chromosome 6qb. Chromosome 6 exhibited a high frequency of trisomies and tetrasomies in the kidney after 5.0 months of estrogen treatment and in primary renal tumors. The data presented indicate that estrogen-induced genomic instability may be a key element in carcinogenic processes induced by estrogens.

Aneuploidy↗

PubMed1999

Role of an ABC importer in mycobacterial drug resistance.

Phosphate specific transporter (Pst) in bacteria is involved in phosphate transport. Pst is a multisubunit system which belongs to the ABC family of transporters. The import function of this transporter is known to be operative at media phosphate concentrations below the millimolar range. However, we found amplification of this transporter in a laboratory generated ciprofloxacin resistant Mycobacterium smegmatis colony (CIPr) which was grown in a condition when phosphate scavenging function of this operon was inoperative. Our results therefore argue the role of this ABC importer in conferring high level of fluoroquinolone resistance in CIPr.

ATP-Binding Cassette Transporters↗

PubMed1999

p53 status, cellular recovery and cell cycle arrest as prognosticators of in vitro radiosensitivity in human pancreatic adenocarcinoma cell lines.

PURPOSE: To investigate the factors contributing to the in vitro radiosensitivity of four human pancreatic adenocarcinoma cell lines differing in p53 status, and the basis for the lack of post-irradiation G1 arrest in the two cell lines that have retained a wild-type p53 allele. MATERIALS AND METHODS: Cells were X-irradiated and the parameters related to radiosensitivity, as well as the modulation of gene products linked to regulation of cell cycle transit (p53, p21/WAF1/CIP1, pRb) or DNA replication and repair (DNA topoisomerase I and II), were determined. RESULTS: Both cell lines expressing either mutant (mt) R248W or R273H p53 proteins were more radioresistant. All the cell lines arrested in G2. None of the cell lines arrested in G1 and this was linked to the inability to upregulate p21/WAF1/CIP1. There were no correlations between p53 status and the magnitude or time of maximum G2 arrest. However, there was a negative correlation between a protracted arrest in G2 and the ability to recover from potentially lethal damage (PLD). CONCLUSIONS: Variation in radiosensitivity is related to p53 status, but the survival advantage conferred by having mutant p53 status is not readily explained neither by recovery from PLD nor by cell cycle arrest kinetics. There is no p53-independent pathway for the recruitment of p21 in these cell lines following irradiation.

Adenocarcinoma↗

PubMed1999

False-positive troponin I in the MEIA due to the presence of rheumatoid factors in serum. Elimination of this interference by using a polyclonal antisera against rheumatoid factors.

We report false-positive cardiac troponin (cTn) I results in the microparticle enzyme immunoassay (MEIA) using the AxSYM analyzer. We studied serum samples from 12 patients with positive rheumatoid factor but with no indication of myocardial infarction (MI); 2 also had positive antinuclear antibody (ANA) titers. Serum samples from 7 patients with positive ANA titers and negative rheumatoid factors also were studied. Total creatine kinase (CK) was run using a Hitachi 747 analyzer, cTnT using an Elecsys 2010 analyzer, and cTnI and CK-MB using an AxSYM analyzer. We observed no measurable cTnI and cTnT concentrations in 12 control samples or in specimens with positive ANA titers and negative rheumatoid factors. In contrast, samples from 7 of 12 patients containing rheumatoid factors had measurable cTnI concentrations. Four specimens showed cTnI concentrations more than 2.0 micrograms/L, the suggested diagnostic cutoff for MI. None of the specimens showed detectable cTnT. The concentrations of total CK and CK-MB were within normal ranges in all specimens. False-positive results were observed only with the MEIA for cTnI. This interference can be eliminated by using a polyclonal antisera against rheumatoid factor. The chemiluminescent assay for cTnI showed no detectable cTnI concentration in any specimen.

Antibodies, Antinuclear↗

PubMed1999

Operator error: a critical determinant of false amikacin and tobramycin concentrations using fluorescence polarization immunoassay kits and TDX analyzer.

Amikacin and tobramycin are aminoglycosides used to treat severe Gram-negative infections. Therapeutic monitoring of both drugs is essential to avoid drug toxicity. Fluorescence polarization immunoassay kits for both amikacin and tobramycin are available from Abbott Laboratories, and assays can be run using the TDx analyzer. The test code for amikacin is 3, whereas the test code for tobramycin is 2. Here the authors report that when the operator mistakenly programmed test code 3 (amikacin code) while using the tobramycin kit, the tobramycin values were falsely elevated. The instrument software does not have any mechanism to detect this error. Similarly, when the amikacin kit was used and the operator mistakenly programmed test code 2 (tobramycin code), the amikacin values were falsely lowered. For example, in a serum sample taken from a patient the true amikacin concentration was 20.9 microg/mL. When the amikacin kit was used correctly but test code 2 was programmed, the observed concentration was falsely lowered to 6.1 microg/mL. Similarly, in another specimen the true tobramycin concentration was 3.1 microg/mL. However, when the tobramycin kit was used correctly but test code 3 was used, the observed concentration was falsely elevated to 14.3 microg/mL. The authors also observed a similar effect with controls and spiked specimens containing either amikacin or tobramycin. They conclude that correct programming of the test code is vital to obtaining useful results in amikacin and tobramycin analysis using the TDx analyzer.

Amikacin↗

PubMed1999

2-methoxyestradiol-induced growth suppression and lethality in estrogen-responsive MCF-7 cells may be mediated by down regulation of p34cdc2 and cyclin B1 expression.

MCF-7 breast cancer cells increase their rate of proliferation, as indicated by incorporation of tritiated thymidine into DNA, when exposed to estrogen. In confirmation of other studies, 10 nM 17beta-estradiol (E2) increased proliferation by 2.8-fold after 6 days of exposure. As indicated by trypan blue exclusion and TUNEL assays, cell survival was increased and apoptosis decreased by the presence of E2. The estradiol metabolite 2-methoxyestradiol (2-ME) when present in the culture medium in concentrations greater than 1 microM for three days, dose-dependently reduced the effectiveness of E2 on cell proliferation by increasing the rate of apoptosis. To examine a mechanism for the increase in apoptosis, expression of p34cdc2 and cyclin B1 protein levels were monitored by examination of immunoblots of their proteins. E2 increased p34cdc2 and cyclin B1 protein levels significantly after 6 days of exposure. This effect was inhibited significantly by the presence of 2-ME. The results indicate that up-regulation of p34cdc2 and cyclin B1 is closely associated with increased survivability and lack of apoptosis in estrogen-induced proliferation of MCF-7 cells. Further, anti-estrogenic effects of 2-ME in these cells can be accounted for by its activation of apoptotic functions, which are correlated with reductions in expression of p34cdc2 and cyclin B1 genes.

2-Methoxyestradiol↗