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1.
Oncogene ; 36(46): 6508, 2017 11 16.
Article in English | MEDLINE | ID: mdl-28925393

ABSTRACT

This corrects the article DOI: 10.1038/onc.2016.320.

2.
Oncogene ; 36(11): 1537-1545, 2017 03.
Article in English | MEDLINE | ID: mdl-27694900

ABSTRACT

Ovarian cancer is the leading cause of death among all gynecological malignancies due to the development of acquired chemoresistance and disease relapse. Although the role of cancer stem cells (CSCs), a subset of tumor cells with the self-renewal and differentiation capabilities, in therapeutic resistance is beginning to be better understood, the significance of epigenetic regulatory mechanisms responsible for integrating the stemness with drug resistance remain poorly understood. Here we identified that lysine demethylase KDM3A as a critical regulator of ovarian cancer stemness and cisplatin resistance by inducing the expressions of pluripotent molecules Sox2 and Nanog and anti-apoptotic B-cell lymphoma 2 (Bcl-2), respectively. In addition, KDM3A induces ovarian cancer growth while antagonizing cellular senescence by repressing the expression of cyclin-dependent kinase inhibitor, p21Waf1/Cip1. The underlying mechanism of the noted biological processes include KDM3A-mediated stimulation of Sox2 expression, and demethylating p53 protein and consequently, modulating its target genes such as Bcl-2 and p21Waf1/Cip1 expression. Consistently, KDM3A depletion inhibited the growth of subcutaneously implanted cisplatin-resistant human ovarian cancer cells in athymic nude mice. Moreover, KDM3A is abundantly expressed and positively correlated with Sox2 expression in human ovarian cancer tissues. In brief, our findings reveal a novel mechanism by which KDM3A promotes ovarian CSCs, proliferation and chemoresistance and thus, highlights the significance of KDM3A as a novel therapeutic target for resistant ovarian cancer.


Subject(s)
Drug Resistance, Neoplasm/genetics , Jumonji Domain-Containing Histone Demethylases/genetics , Jumonji Domain-Containing Histone Demethylases/metabolism , Lysine/metabolism , Neoplastic Stem Cells/metabolism , Ovarian Neoplasms/genetics , Ovarian Neoplasms/metabolism , Animals , Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Apoptosis/genetics , Cell Cycle/genetics , Cell Line, Tumor , Cellular Senescence/drug effects , Cellular Senescence/genetics , Cisplatin/pharmacology , Cyclin-Dependent Kinase Inhibitor p21/genetics , Cyclin-Dependent Kinase Inhibitor p21/metabolism , Disease Models, Animal , Epigenesis, Genetic , Female , Gene Expression , Gene Knockdown Techniques , Heterografts , Humans , Mice , Ovarian Neoplasms/drug therapy , Ovarian Neoplasms/pathology , Proto-Oncogene Proteins c-bcl-2/genetics , Proto-Oncogene Proteins c-bcl-2/metabolism , SOXB1 Transcription Factors/genetics , SOXB1 Transcription Factors/metabolism , Tumor Suppressor Protein p53/metabolism
3.
Br J Cancer ; 108(4): 848-58, 2013 Mar 05.
Article in English | MEDLINE | ID: mdl-23403820

ABSTRACT

BACKGROUND: Breast cancer, a heterogeneous disease has been broadly classified into oestrogen receptor positive (ER+) or oestrogen receptor negative (ER-) tumour types. Each of these tumours is dependent on specific signalling pathways for their progression. While high levels of survivin, an anti-apoptotic protein, increases aggressive behaviour in ER- breast tumours, oxidative stress (OS) promotes the progression of ER+ breast tumours. Mechanisms and molecular targets by which OS promotes tumourigenesis remain poorly understood. RESULTS: DETA-NONOate, a nitric oxide (NO)-donor induces OS in breast cancer cell lines by early re-localisation and downregulation of cellular survivin. Using in vivo models of HMLE(HRAS) xenografts and E2-induced breast tumours in ACI rats, we demonstrate that high OS downregulates survivin during initiation of tumourigenesis. Overexpression of survivin in HMLE(HRAS) cells led to a significant delay in tumour initiation and tumour volume in nude mice. This inverse relationship between survivin and OS was also observed in ER+ human breast tumours. We also demonstrate an upregulation of NADPH oxidase-1 (NOX1) and its activating protein p67, which are novel markers of OS in E2-induced tumours in ACI rats and as well as in ER+ human breast tumours. CONCLUSION: Our data, therefore, suggest that downregulation of survivin could be an important early event by which OS initiates breast tumour formation.


Subject(s)
Breast Neoplasms/genetics , Down-Regulation , Inhibitor of Apoptosis Proteins/genetics , Oxidative Stress/genetics , Animals , Breast Neoplasms/metabolism , Cell Line, Tumor , Dual Specificity Phosphatase 6/genetics , Female , Gene Expression Regulation, Neoplastic , Humans , Mice , Mice, Nude , Rats, Inbred ACI , Survivin , Transplantation, Heterologous
4.
Br J Cancer ; 105(3): 428-37, 2011 Jul 26.
Article in English | MEDLINE | ID: mdl-21730980

ABSTRACT

BACKGROUND: Mechanisms that increase resistance to apoptosis help promote cellular transformation. Cancer cells have deregulated apoptotic pathways, where increased expression and stability of anti-apoptotic proteins Mcl-1 and Bcl-2 increases resistance to apoptosis. Pathways that increase the stability of proteins in cancer cells remain poorly understood. METHODS: Using human mammary epithelial and established breast cancer cell lines, we assessed the mechanisms that increase the stability of anti-apoptotic proteins in breast cancer cells by caspase assay, western blot, small-inhibitory RNA treatment and immunoprecipitation. RESULTS: While breast cancer cells were resistant to de novo inhibition of protein synthesis, a rapid proteosome-mediated degradation of Mcl-1 and Bcl-2 induced apoptosis in mammary epithelial cells. Although Mule, an E3 ligase that targets Mcl-1 for degradation was expressed in mammary epithelial and breast cancer cell lines, rapid increase of polyubiquitinated Mcl-1 and Bcl-2 was detected only in mammary epithelial cells. Only transient formation of the Mule-Mcl-1 complex was detected in breast cancer cells. Downregulation of pERK1/2 in breast cancer cells reduced Mcl-1 levels and increased Mcl-1/Mule complex. CONCLUSION: Our findings suggest that reduced Mule/Mcl-1 complex has a significant role in increasing the stability of Mcl-1 in breast cancer cells and increased resistance to apoptosis.


Subject(s)
Apoptosis Regulatory Proteins/chemistry , Breast Neoplasms/metabolism , Proto-Oncogene Proteins c-bcl-2/chemistry , Ubiquitin-Protein Ligases/metabolism , Apoptosis Regulatory Proteins/metabolism , Cell Line, Tumor , Down-Regulation , Epithelial Cells/metabolism , Humans , Macromolecular Substances/metabolism , Mitogen-Activated Protein Kinase 1/metabolism , Mitogen-Activated Protein Kinase 3/metabolism , Myeloid Cell Leukemia Sequence 1 Protein , Protein Stability , Proto-Oncogene Proteins c-bcl-2/metabolism , Tumor Suppressor Proteins , Ubiquitin-Protein Ligases/chemistry , Ubiquitination
5.
Burns ; 37(4): 692-7, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21334818

ABSTRACT

Burn scar hand contractures of variable degree are frequently encountered. Although the forearm is apparently spared, it was clinically observed that there was disuse atrophy in the unburnt extrinsic forearm muscles. Usually the clinicians do not give much importance to this fact. The girth at the midforearm was significantly reduced as compared to normal side. The flexion of the hand joints are governed by two components (a) intrinsic and (b) extrinsic muscles. The intrinsic muscles are directly involved in the contracted tissue. Therefore it was thought essential to evaluate the extrinsic group of muscles for their contribution in the final functional recovery following corrective surgery. Thirty patients having unilateral post thermal burn contracture sparing forearm were studied. A detailed clinical evaluation was made including grade of contracture and reduction in the forearm girth. The forearm unburnt muscles were evaluated by preoperative electrophysiological studies. Intraoperative biopsies were taken from these muscles for histopathological examination. On histopathological examination, there were significant abnormal changes in the form of muscle fiber atrophy, fibrolipomatous tissue replacement of atrophic muscle fibers and sarcolemmal changes. These changes were directly proportional to the severity of contractures. The electrophysiological studies showed proportionate changes in the form of reduction in amplitude, duration and interference. This study suggests that if these changes are mild and in reversible stage, they will favourably affect the functional recovery following surgery. However if these changes are of severe grade and irreversible, in spite of adequate surgery, splinting and physiotherapy, the functional recovery may not be complete.


Subject(s)
Burns/complications , Contracture/physiopathology , Electrophysiology , Hand Injuries/physiopathology , Muscle, Skeletal/physiopathology , Adolescent , Adult , Burns/pathology , Child , Child, Preschool , Collagen/analysis , Contracture/pathology , Female , Forearm/physiopathology , Hand Injuries/etiology , Humans , Male , Muscle Fibers, Skeletal/pathology , Muscle, Skeletal/pathology , Young Adult
6.
Ann Hematol ; 86(7): 483-5, 2007 Jul.
Article in English | MEDLINE | ID: mdl-17401564

ABSTRACT

Hereditary hemochromatosis is an autosomal recessive and most commonly inherited single gene disorder among Caucasians, with a prevalence of 5 per 1,000 and a carrier frequency of 1 in 10. Two point mutations were described and are referred as C282Y and H63D. In the present study, we have analyzed 729 north Indian samples for C282Y and H63D mutations. Of these, no allele of the C282Y mutation was seen, while 3 homozygous and 43 heterozygous for the H63D mutation were seen in the patients of thalassemia group. However, 47 cases were found heterozygous for the H63D mutation among the normal groups (11.16%).


Subject(s)
Histocompatibility Antigens Class I/genetics , Membrane Proteins/genetics , Polymorphism, Single Nucleotide/genetics , Thalassemia/genetics , Case-Control Studies , Gene Frequency , Hemochromatosis Protein , Heterozygote , Humans , India/epidemiology , Iron Overload/genetics , Prevalence , Thalassemia/epidemiology
8.
Indian J Otolaryngol Head Neck Surg ; 58(3): 271-3, 2006 Jul.
Article in English | MEDLINE | ID: mdl-23120310

ABSTRACT

Otitis media with effusion is one of the commonest otological problems in paediatric age group. The condition occurs in childhood as overt or covert hearing loss presenting as an educational or behavioural problem. As there is widespread controversy regarding its precise aetiology, natural history and pathogenesis a treatment dilemma still persists. The main goal of this study is to compare the efficacy of different modalities of medical and surgical treatment designed for this condition and analysis of the results statistical.

9.
Carcinogenesis ; 22(11): 1863-9, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11698350

ABSTRACT

We have shown previously that (NOHA) an intermediate in the nitric oxide (NO) synthetic pathway and an inhibitor of arginase significantly reduced intracellular polyamines, activated caspase-3 and induced apoptosis in the human breast cancer cell line MDA-MB-468. These actions of NOHA were abolished in the presence of exogenous L-ornithine suggesting that a reduction in the intracellular polyamine content might be responsible for the activation of caspase-3 and apoptotic actions of NOHA. In order to further explore this possibility, we used SAM-486A and alpha-difluoromethylornithine (DFMO), which are inhibitors of S-adenosylmethionine decarboxylase (SAMDC), and ornithine decarboxylase (ODC), respectively, either alone or in combination to reduce the intracellular polyamine levels. We then assessed whether a reduction in polyamine levels by these two compounds to a similar degree to that produced by NOHA activated caspase-3 which occurs prior to the onset of apoptosis. We observed that both SAM-486A and DFMO, either alone or in combination, inhibited cell proliferation, induced p21 and arrested cells in the G(0)-G(1) phase of the cell cycle but failed to activate caspase-3 as assessed by enzymatic assay of caspase-3, western blot analysis of the proteolytic cleavage of caspase-3 protein as well as TUNEL assay. Furthermore, pre-incubation of the cells with SAM-486A and DFMO for 4 days, either alone or in combination significantly inhibited the activation of caspase-3 and apoptosis by NOHA when compared with that observed with cells treated with NOHA alone. Our results, therefore, indicate that the activation of caspase-3 and apoptosis observed with NOHA cannot be solely explained by a reduction in intracellular polyamine levels and that other mechanisms need to be also considered.


Subject(s)
Apoptosis , Arginase/antagonists & inhibitors , Arginine/analogs & derivatives , Arginine/pharmacology , Breast Neoplasms/metabolism , Caspases/metabolism , Polyamines/metabolism , Tumor Cells, Cultured/drug effects , Adenosylmethionine Decarboxylase/antagonists & inhibitors , Blotting, Western , Breast Neoplasms/pathology , Caspase 3 , Cell Division/drug effects , Cyclin-Dependent Kinase Inhibitor p21 , Cyclins/metabolism , Enzyme Activation , Enzyme Inhibitors/pharmacology , Humans , In Situ Nick-End Labeling , Ornithine/pharmacology , Ornithine Decarboxylase/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Tumor Cells, Cultured/metabolism , Tumor Cells, Cultured/pathology
10.
Biochem Pharmacol ; 62(5): 569-80, 2001 Sep 01.
Article in English | MEDLINE | ID: mdl-11585054

ABSTRACT

Leishmania, a parasitic protozoan, infects human macrophages, often causing severe morbidity and mortality. The pathogenic form of this parasite, the amastigote, lives inside the acidic phagolysosomes of infected macrophages. In our attempt to develop anti-miniexon phosphorothioate oligodeoxyribonucleotides (S-oligos) as an alternative chemotherapy against Leishmania, we found that intracellular as well as 'axenic' amastigotes were more susceptible to these S-oligos than were the cultured promastigotes. Lower pH (4.5) and elevated temperature (35 degrees) of the medium were among the direct enhancing factors for killing. Addition of the cationic polypeptide poly-l-lysine (PLL) to the growth medium further enhanced the killing effect of the S-oligo at pH 4.5. The enhancement of specific ablation of mRNA expression was directly correlated to the increased leishmanicidal activity of the S-oligo. This was shown by the increased inhibition of luciferase activity expressed in transgenic Leishmania amazonensis promastigotes by anti-miniexon S-oligo or anti-luciferase S-oligo at acidic pHs and in the presence of PLL. The leishmanicidal effects of S-oligos at acidic pH and in the presence of PLL were related to increased uptake of the S-oligos under these conditions. The rate of S-oligo uptake was enhanced up to 15-fold at pH 4.5. The addition of PLL to the assay medium at acidic pH further enhanced the uptake of S-oligo up to 80-fold. RNase H is known to accentuate the antisense action of S-oligos. We found that at an elevated temperature RNase H activity in Leishmania cell extracts increased about 5-fold. Thus, enhanced uptake of S-oligos at the acidic pH of macrophage phagolysosomes and activation of RNase H may explain the efficient killing of the parasite in macrophages, both in tissue culture and in the animal model, by antisense miniexon oligonucleotide/PLL, when targeted directly to the parasite-containing phagolysosomes.


Subject(s)
Leishmania/drug effects , Oligodeoxyribonucleotides, Antisense/pharmacology , Polylysine/pharmacology , Ribonuclease H/metabolism , Thionucleotides/pharmacology , Animals , Disease Models, Animal , Drug Carriers , Drug Delivery Systems , Drug Interactions , Enzyme Activation , Germ-Free Life/drug effects , Hydrogen-Ion Concentration , Leishmania/metabolism , Leishmaniasis/drug therapy , Liposomes , Luciferases/biosynthesis , Luciferases/drug effects , Macrophages/drug effects , Macrophages/parasitology , Mice , Mice, Inbred BALB C , Oligodeoxyribonucleotides, Antisense/pharmacokinetics , Oligodeoxyribonucleotides, Antisense/therapeutic use , Parasitic Sensitivity Tests , Phagosomes/drug effects , Phagosomes/parasitology , Temperature , Thionucleotides/pharmacokinetics , Thionucleotides/therapeutic use , Transfection
11.
Med Hypotheses ; 57(3): 393-7, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11516235

ABSTRACT

Recently in an open population-based program composed of 15 354 pregnant women in Colombia we applied a biopsychosocial risk model, which permitted us to identify pregnant women at high risk of preeclampsia. 1443 (9.4%) of patients at high risk for developing preeclampsia received 450 mg of linoleic acid, and 1.5 g/day of calcium. Bacteriuria was identified in 1766 (11.5%) and vaginal infections in 2150 (14.0%) of the pregnant women. These women received oral antibiotics for 10 days. The incidence of low birthweight, preterm delivery and preeclampsia were reduced by 53% (6.2% vs 13.2%), 64.7% (1.8% vs 5.1%), and 52.5% (3.8% vs 8.0%) respectively, when compared with the incidence of the preceding five years. We believe that these dramatic reductions were due to early identification of risk factors, administration of nutritional supplements and principally by treatment of asymptomatic infections. Unfortunately, because of the study design it is not possible to confirm that infection was the major risk factor for preeclampsia in our population. However, we hypothesize that chronic subclinical infections may cause increased maternal cytokine levels sufficient to affect vascular endothelial function, and so prime individuals for the subsequent development of preeclampsia. This hypothesis can be tested in a more appropriately designed clinical trial to assess whether there is a relationship between infection, inflammation and preeclampsia.


Subject(s)
Pre-Eclampsia/etiology , Pregnancy Complications, Infectious , Anti-Bacterial Agents/therapeutic use , Colombia/epidemiology , Female , Humans , Infant, Newborn , Pre-Eclampsia/epidemiology , Pregnancy , Pregnancy Complications, Infectious/drug therapy , Pregnancy Outcome , Risk Factors
12.
J Org Chem ; 66(1): 20-9, 2001 Jan 12.
Article in English | MEDLINE | ID: mdl-11429900

ABSTRACT

A highly convenient method has been developed for the synthesis of (Z)-4-alkyl-2-alkyl(aryl)idene-3,4-dihydro-2H-1,4-benzoxazines 9 and (Z)-3-alkyl(aryl)idene-4-tosyl-3,4-dihydro-2H-1,4-benzoxazines 34-38 through palladium-copper-catalyzed reactions. Aryl halides 7 reacted with 2-[N-alkyl(benzyl)-N-prop-2'-ynyl]aminophenyl tosylate 6 in the presence of (PPh3)2PdCl2 (3 mol %), CuI(5 mol %) in triethylamine at room temperature to yield 2-[N-alkyl(benzyl)-N-(3-aryl-prop-2'-ynyl)]-aminophenyl tosylates 8 in extremely good yields (72-96%). The latter could then be cyclized with KOH in ethanol-water to Z-9 in a highly regio- and stereoselective manner. Similarly, palladium-copper-catalyzed reaction of 2-(prop-2'-ynyloxy)aniline (21) with aryl iodides 7 led to 22-26 which after tosylation and cyclization with cuprous iodide in CH3CN in the presence of K2CO3 and Bu4-NBr led to the (Z)-3-alkyl(aryl)idene-4-tosyl 3,4-dihydro-2H-1,4-benzoxazines 34-38 in good overall yields. The Z-stereochemistry of the products was established from 1H NMR spectra, 3JCH values (between vinylic proton and methylenic carbon of the heterocyclic ring), NOE experiments, and X-ray analysis. The method was also found to be suitable for the synthesis of bis(benzoxazinylated) derivatives 17, 39, and 2-alkyl-3,4-dihydro-2H-1,4-benzoxazines 18. Our method for the synthesis of 3,4-dihydro-2H-1,4-benzoxazines is highly efficacious, using easily available starting materials under very mild conditions. Also the synthesis of some novel 5-substituted uracil derivatives 40 and 41 containing the benzoxazinyl moiety and of potential biological interest is being reported.

13.
Cancer Res ; 61(12): 4701-6, 2001 Jun 15.
Article in English | MEDLINE | ID: mdl-11406540

ABSTRACT

High amounts of nitric oxide (NO) produced by activated macrophages or NO donors are required to induce cytotoxicity and apoptosis in pathogens and tumor cells. High concentrations of NO may lead to nonspecific toxicity thereby limiting the use of NO donors in the treatment of cancer. In this study, we tested the possibility of potentiating the apoptotic action of NO in a human breast cancer cell line, MDA-MB-468, by combining it with a farnesyltransferase inhibitor (FTI), which has been shown to induce apoptosis in some other cancer cell lines with minimal toxicity to normal cells. DETA-NONOate, a long acting NO donor which has a half-life of 20 h at 37 degrees C, was used in this study. DETA-NONOate (1 mM), which releases NO in the range produced by activated macrophages, induced apoptosis after 36 h in MDA-MB-468 cells via cytochrome c release and caspase-9 and -3 activation. FTI (25 microM) potentiated the action of lower concentrations of DETA-NONOate (25-100 microM) by inducing apoptosis in these cells within 24 h by increasing cytochrome c release and caspase-9 and -3 activation. This effect was observed preferentially in the cancer cell lines studied with no apoptosis induction in normal breast epithelial cells. This novel combination of FTI and NO may emerge as a promising approach for the treatment of breast cancer.


Subject(s)
Alkyl and Aryl Transferases/antagonists & inhibitors , Apoptosis/drug effects , Breast Neoplasms/pathology , Nitric Oxide/pharmacology , Apoptosis/physiology , Breast Neoplasms/drug therapy , Breast Neoplasms/enzymology , Drug Synergism , Enzyme Inhibitors/pharmacology , Farnesyltranstransferase , Humans , Nitric Oxide/pharmacokinetics , Nitric Oxide Donors/pharmacokinetics , Nitric Oxide Donors/pharmacology , Nitroso Compounds/pharmacokinetics , Nitroso Compounds/pharmacology , Tumor Cells, Cultured
14.
Acta Crystallogr C ; 57(Pt 6): 740-1, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11408691

ABSTRACT

In the title compound, C22H17Cl2NO3S, the molecule is a substituted 3,4-dihydro-2H-1,4-benzoxazine compound which has three phenyl rings which are essentially planar. The 3,4-dihydro-2H-oxazine part of the molecule is fused to the benzo ring and has a half-boat conformation; the dihedral angle between the planar part of the oxazine ring and the benzo ring is 10.2 (2) degrees. The (3-chlorophenyl)methylidene substituent has a Z configuration in relation to the ring N atom of the oxazine moiety. Interestingly, the p-toluenesulfonyl (p-tosyl) substituent on the ring N atom protrudes away from the 3-chlorophenyl substituent thus avoiding any steric interaction.


Subject(s)
Oxazines/chemistry , Tosyl Compounds/chemistry , Crystallography, X-Ray , Molecular Structure
15.
Am J Physiol Regul Integr Comp Physiol ; 280(5): R1546-54, 2001 May.
Article in English | MEDLINE | ID: mdl-11294780

ABSTRACT

In women, during pregnancy, there is decreased motility of the gastrointestinal tract leading to a delay in gastric emptying and an increase in colonic transit time. Whether the rise in estradiol (E2) or progesterone (P4) is responsible for this effect is controversial. As the nitrergic component of the nonadrenergic, noncholinergic (NANC) nerves is responsible for modulating gastrointestinal motility in vivo, the purpose of this study was to evaluate whether the increased release of nitric oxide (NO) from the nitrergic component of the NANC nerves innervating the gastric fundus and colon that occurs during late pregnancy in rats is mediated by E2 or P4. Ovariectomized rats treated with E2 or P4 alone or in combination were used for our studies. We also wanted to assess the cellular and molecular mechanisms involved. The NANC activity was studied by assessing changes in tone after application of electric field stimulation (EFS). The role of NO was determined by observing the effects of EFS in the presence and absence of the NO synthase (NOS) inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) and the reversibility of the effects of L-NAME by L-arginine. Our studies indicated that there was increased magnitude of relaxation of isolated strips of rat gastric fundus and rat colon after application of EFS to tissues obtained from animals treated with E2 alone or a combination of E2 + P4 but not from those treated with P4 alone. L-NAME attenuated relaxation responses in E2- and E2 + P4-treated animals. To elucidate whether the increased NO release may be due to an increase in neuronal NOS (nNOS) protein, we used both Western blot analysis and immunohistochemistry. We also used RT-PCR to determine whether there was an increase in nNOS mRNA after treatment with sex steroids. In nonpregnant animals, nNOS was detected by Western blot in the fundus and the colon and was barely detectable in the ileum. In pregnancy, there was an increase in nNOS in both the gastric fundus and the colon. The nNOS protein was also increased in ovariectomized animals treated with either E2 alone or E2 + P4 but not P4 alone when compared with ovariectomized animals receiving vehicle. Our results indicated that there was an increase in nNOS protein that was localized to the neurons of the myenteric plexus in the gastric fundus and colon in E2- and E2 + P4-treated animals, but this increase was not observed in animals treated with P4 alone. This increase in nNOS protein was accompanied by an increase in nNOS mRNA. These results suggest the possibility that E2, rather than P4, may be responsible for the delay in gastric emptying and increase in colonic transit time observed in pregnancy.


Subject(s)
Digestive System/innervation , Estradiol/physiology , Muscle, Smooth/physiology , Pregnancy, Animal/physiology , Progesterone/physiology , Animals , Arginine/pharmacology , Colon/drug effects , Colon/physiology , Electric Stimulation , Estradiol/pharmacology , Female , Humans , Ileum/drug effects , Ileum/physiology , In Vitro Techniques , Muscle Contraction/drug effects , Muscle Contraction/physiology , Muscle Relaxation/drug effects , Muscle Relaxation/physiology , Muscle, Smooth/drug effects , NG-Nitroarginine Methyl Ester/pharmacology , Nitric Oxide/physiology , Ovariectomy , Pregnancy , Progesterone/pharmacology , Rats , Rats, Sprague-Dawley , Stomach/drug effects , Stomach/physiology
16.
Proc Natl Acad Sci U S A ; 98(6): 3583-8, 2001 Mar 13.
Article in English | MEDLINE | ID: mdl-11248121

ABSTRACT

DETA-NONOate, a nitric oxide (NO) donor, induced cytostasis in the human breast cancer cells MDA-MB-231, and the cells were arrested in the G(1) phase of the cell cycle. This cytostatic effect of the NO donor was associated with the down-regulation of cyclin D1 and hypophosphorylation of the retinoblastoma protein. No changes in the levels of cyclin E or the catalytic partners of these cyclins, CDK2, CDK4, or CDK6, were observed. This NO-induced cytostasis and decrease in cyclin D1 was reversible for up to 48 h of DETA-NONOate (1 mM) treatment. DETA-NONOate (1 mM) produced a steady-state concentration of 0.5 microM of NO over a 24-h period. Synchronized population of the cells exposed to DETA-NONOate remained arrested at the G(1) phase of the cell cycle whereas untreated control cells progressed through the cell cycle after serum stimulation. The cells arrested at the G(1) phase after exposure to the NO donor had low cyclin D1 levels compared with the control cells. The levels of cyclin E and CDK4, however, were similar to the control cells. The decline in cyclin D1 protein preceded the decrease of its mRNA. This decline of cyclin D1 was due to a decrease in its synthesis induced by the NO donor and not due to an increase in its degradation. We conclude that down-regulation of cyclin D1 protein by DETA-NONOate played an important role in the cytostasis and arrest of these tumor cells in the G(1) phase of the cell cycle.


Subject(s)
Cyclin D1/physiology , Nitric Oxide/metabolism , Breast Neoplasms , Cell Cycle , Cell Division , Cyclin D1/biosynthesis , Cyclin D1/genetics , Cyclin D1/metabolism , Down-Regulation , G1 Phase , Growth Inhibitors/pharmacology , Humans , Nitric Oxide Donors/pharmacology , Nitroso Compounds/pharmacology , Tumor Cells, Cultured
17.
Proc Natl Acad Sci U S A ; 98(6): 3589-93, 2001 Mar 13.
Article in English | MEDLINE | ID: mdl-11248122

ABSTRACT

The effects of testosterone on early atherogenesis and the role of aromatase, an enzyme that converts testosterone to estrogens, were assessed in low density lipoprotein receptor-deficient male mice fed a Western diet. Castration of male mice increased the extent of fatty streak lesion formation in the aortic origin compared with testes-intact animals. Administration of anastrazole, a selective aromatase inhibitor, to testes-intact males increased lesion formation to the same extent as that observed with orchidectomized animals. Testosterone supplementation of orchidectomized animals reduced lesion formation when compared with orchidectomized animals receiving the placebo. This attenuating effect of testosterone was not observed when the animals were treated simultaneously with the aromatase inhibitor. The beneficial effects of testosterone on early atherogenesis were not explained by changes in lipid levels. Estradiol administration to orchidectomized males attenuated lesion formation to the same extent as testosterone administration. Aromatase was expressed in the aorta of these animals as assessed by reverse transcription-PCR and immunohistochemistry. These results indicate that testosterone attenuates early atherogenesis most likely by being converted to estrogens by the enzyme aromatase expressed in the vessel wall.


Subject(s)
Aromatase/physiology , Coronary Artery Disease/pathology , Estradiol/metabolism , Testosterone/metabolism , Animals , Aorta/enzymology , Aromatase/genetics , Aromatase Inhibitors , Cholesterol/blood , Coronary Vessels/drug effects , Coronary Vessels/pathology , Estradiol/administration & dosage , Estradiol/blood , Estradiol/pharmacology , Gene Expression , Lipoproteins, HDL/blood , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Orchiectomy , Testosterone/administration & dosage , Testosterone/blood
18.
Biochem Pharmacol ; 61(4): 467-76, 2001 Feb 15.
Article in English | MEDLINE | ID: mdl-11226381

ABSTRACT

Ribonuclease H (RNase H), an enzyme that cleaves an RNA sequence base-paired with a complementary DNA sequence, is proposed to be the mediator of antisense phosphorothioate oligonucleotide (S-oligo) lethality in a cell. To understand the role of RNase H in the killing of the parasitic protozoan Leishmania by antisense S-oligos, we expressed an episomal copy of the Trypanosoma brucei RNase H1 gene inside L. amazonensis promastigotes and amastigotes that constitutively express firefly luciferase. Our hypothesis was that S-oligo-directed degradation of target mRNA is facilitated in a cell that has higher RNase H activity. Increased inhibition of luciferase mRNA expression by anti-luciferase S-oligo and by anti-miniexon S-oligo in these stably transfected promastigotes overexpressing RNase H1 was correlated to the higher activity of RNase H in these cells. The efficiency of killing of the RNase H overexpressing amastigotes inside L. amazonensis-infected macrophages by anti-miniexon S-oligo was higher than in the control cells. Thus, RNase H appears to play an important role in the antisense S-oligo-mediated killing of Leishmania. Chemical modification of S-oligos that stimulate RNase H and/or co-treatment of cells with an activator of RNase H may be useful for developing an antisense approach against leishmaniasis. The transgenic Leishmania cells overexpressing RNase H should be a good model system for the antisense-mediated gene expression ablation studies in these parasites.


Subject(s)
Antiprotozoal Agents/pharmacology , Leishmania/drug effects , Oligonucleotides, Antisense/pharmacology , Ribonuclease H/physiology , Thionucleosides/pharmacology , Animals , Base Sequence , DNA, Protozoan/analysis , Drug Evaluation, Preclinical , Gene Expression/drug effects , Leishmania/enzymology , Leishmania/genetics , Leishmania/metabolism , Luciferases/biosynthesis , Luciferases/genetics , Molecular Sequence Data , RNA, Messenger/biosynthesis , RNA, Messenger/drug effects , Ribonuclease H/biosynthesis , Transfection , Trypanosoma brucei brucei/drug effects , Trypanosoma brucei brucei/enzymology , Trypanosoma brucei brucei/metabolism
19.
Indian J Exp Biol ; 39(12): 1249-53, 2001 Dec.
Article in English | MEDLINE | ID: mdl-12018519

ABSTRACT

Adult male rats received daily injections (sc) of gonadotropin releasing hormone antagonist (0.2 mg/kg(-1) x day(-1)) for 21 days when they were sacrificed on day 22, adrenal weight, adrenal A5-3beta (delta 5-3beta) hydroxysteroid dehydrogenase (Delta5-3beta-HSD) activity and serum level of corticosterone were increased significantly while testicular 17beta (17beta) hydroxysteroid dehydrogenase (17beta-HSD) activity and serum level of testosterone and spermatogenesis were decreased in the rats fed on 5% casein diet. GnRH antagonist treated rats fed on 20% casein diet, resulted significant decrease in adrenal weight, serum corticosterone and adrenal A5-3beta-HSD activity while testicular 17beta-HSD activity serum testosterone levels and the weights of sex organs were increased with respect to anti GnRH treated rats fed on 5% casein diet. But the GnRH antagonist treated rats fed on 20% casein diet showed decreased spermatogenesis quantitatively and sperm count appeared similar to anti GnRH treated rats fed on 5% casein diet. These results indicate that high casein diet protects adrenocortical activity and stimulates testosterone synthesis without effecting spermatogenic arrest in GnRH antagonist treated rats. It may be concluded that GnRH antagonist in presence of high milk protein diet may be considered to be a suitable antihormone in the development of an ideal male contraceptive.


Subject(s)
Adrenal Glands/physiology , Caseins/administration & dosage , Dietary Proteins/administration & dosage , Gonadotropin-Releasing Hormone/antagonists & inhibitors , Testis/physiology , Adrenal Glands/enzymology , Animals , Hydroxysteroid Dehydrogenases/metabolism , Male , Rats , Rats, Wistar , Spermatogenesis , Testis/enzymology
20.
Disabil Rehabil ; 22(15): 690-2, 2000 Oct 15.
Article in English | MEDLINE | ID: mdl-11087065

ABSTRACT

PURPOSE: This is a case study of improvement in pelvic instability due to a stroke, with treatment. The patient had narrow knee-to-knee distance due to weakness in the pelvic muscles resulting in a narrow base of support. METHOD: Treatment was focused on pre-gait activities to improve upright posture control followed by gait training involving extrinsic auditory feedback about knee-to-knee distance. RESULTS: After two weeks of therapy with feedback technique incorporated in a functional context of gait therapy, the patient was able to advance his left lower extremity with proper foot placement. Laboratory measurements showed that step width and stride length gotten better after treatment as well. CONCLUSION: An inclusion of feedback information about knee-to-knee distance could benefit gait training of patients with pelvic instability.


Subject(s)
Biofeedback, Psychology , Joint Instability/therapy , Pelvis , Physical Therapy Modalities , Stroke Rehabilitation , Aged , Gait , Humans , Male
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