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Gulia A, Puri A, Kamath N, Thakur R, Laskar S, Bajpai J, Khanna N, Chinnaswamy G, Rekhi B. 436P Oncologic outcomes in patients with extraskeletal Ewing’s sarcoma (EES): A tertiary care centre experience. Ann Oncol 2022. [DOI: 10.1016/j.annonc.2022.10.467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
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Kamath N, Iyengar A, V Reddy H, Uthup S, Sharma J, Singhal J, Ekambaram S, Shroff R. SAT-271 DETERMINING THE OPTIMAL DOSE OF CHOLECALCIFEROL SUPPLEMENTATION IN CHILDREN WITH CHRONIC KIDNEY DISEASE (C3 TRIAL) - AN OPEN LABEL MULTICENTRE RANDOMIZED CONTROLLED TRIAL. Kidney Int Rep 2019. [DOI: 10.1016/j.ekir.2019.05.308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Pierce A, Mansour S, Kamath N, Lin P. A multi-omics approach to metabolically optimize a xeno free, serum free medium for T cell expansion. Cytotherapy 2019. [DOI: 10.1016/j.jcyt.2019.03.342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Pinapala A, Garg M, Kamath N, Iyengar A. Clinical and Genetic Profile of Indian Children with Primary Hyperoxaluria. Indian J Nephrol 2017; 27:222-224. [PMID: 28553045 PMCID: PMC5434691 DOI: 10.4103/0971-4065.202831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Primary hyperoxaluria (PH) has heterogeneous renal manifestations in infants and children. This often leads to delay in diagnosis. In the past 3 years, genetic samples were sent for seven children with a clinical diagnosis of PH. Their medical records were reviewed for clinical presentation and outcomes. Of the seven children, three were males. The median age of presentation was 4.9 years with the youngest presenting at 3 months of age. Nephrolithiasis, the most common presentation was associated with renal dysfunction in two children. Two children with no significant history presented in end-stage renal disease (ESRD). The sibling of one of the children in ESRD, with a history of consanguinity in parents, was screened for asymptomatic nephrolithiasis. Bilateral multiple renal calculi were found in majority of children followed by echogenic kidneys on ultrasound examination. Genetic analysis suggested PH Type 1 in five children and type 2 in two children. The mutations detected in our cohort were different from the previously reported common mutations. There was no obvious genotype-phenotype correlation noticed. Three children in ESRD are on maintenance dialysis. Nephrolithiasis being a common presentation of PH needs prompt evaluation. Mutations are generally population specific, and whole gene sequence analysis is critical in diagnosis.
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Affiliation(s)
- A Pinapala
- Department of Pediatric Nephrology, St. John's Medical College Hospital, Bengaluru, Karnataka, India
| | - M Garg
- Department of Pediatric Nephrology, St. John's Medical College Hospital, Bengaluru, Karnataka, India
| | - N Kamath
- Department of Pediatric Nephrology, St. John's Medical College Hospital, Bengaluru, Karnataka, India
| | - A Iyengar
- Department of Pediatric Nephrology, St. John's Medical College Hospital, Bengaluru, Karnataka, India
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Salian S, Vahab SA, Shah H, Shukla A, Shenoy R, Kamath N, Shenoy J, Satyamoorthy K, Girisha KM. EVALUATION OF MULTIPLEX LIGATION DEPENDENT PROBE AMPLIFICATION AS A TOOL FOR DIAGNOSIS AND CARRIER DETECTION IN FAMILIES WITH A DYSTROPHINOPATHY. Genet Couns 2016; 27:449-460. [PMID: 30226963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We set out to evaluate multiplex ligation dependent probe amplification (MLPA) as a tool for diagnosis and carrier detection in families with a dystrophinopathy. Fifty three Indian families with provisional diagnosis of Duchene muscular dystrophy or Becker muscular dystrophy were evaluated by MLPA and multiplex polymerase chain reaction (PCR). Sanger sequencing was used to analyze the entire gene in one patient. Mothers were tested for carrier status whenever possible. Molecular analysis of DMD gene by combining MLPA and multiplex PCR yielded a mutation detection rate of 62% (33/53). Deletions were detected in 27/53 (51%) cases, duplications in 5/53 (9%) cases, a small deletion one case and Sanger sequencing detected a nonsense mutation in one case. Mutation was not detected in 36% (19/53) cases. Fifty six percent of mothers (9/16) were found to be carriers. MLPA helped to refine the results of multiplex PCR testing in 22 patients (5 duplications, 16 deletions and one small deletion). We also describe a situation where a deletion of single exon on MLPA (but not detected by multiplex PCR) was actually due to a deletion of two nucleotides in the probe ligation site. MLPA appears to score over multiplex PCR in diagnosis and carrier detection, specifically by detecting deletions and duplications that are not detected by traditional multiplex PCR.
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Abstract
Cyclosporine A (CyA) is an effective agent for the treatment of glucocorticoid-dependent idiopathic nephrotic syndrome (GCDNS), but costs are prohibitive in resource-poor societies. The objectives of this study were to evaluate the efficacy and safety of reducing the dose of CyA by co-administering ketoconazole. A prospective study targeting children 2-18 years of age with GCDNS in remission with CyA monotherapy was conducted. CyA dose was reduced by 50% and ketoconazole was added at 25% of the recommended therapeutic dose, and the drug levels and therapeutic and adverse effects (AE) were monitored. Continued combined therapy after completion of the 4-week trial period was offered. Ten patients (median age 9.5 years, range 3.0-16.0 years) were enrolled in the study. At week 4, the CyA dose was 2.2 ± 0.7 mg/kg/day compared with 5.6 ± 0.9 mg/kg/day at enrolment (P < 0.0001). No AE were noted. All patients continued ketoconazole treatment for at least 3 months. CyA drug cost savings were 61%, and approximately 60% with ketoconazole cost included. The combination of an expensive immunosuppressive drug with a cheap metabolic inhibitor reduced the treatment costs by> 50% without increased adverse events or drug monitoring needs. This intervention demonstrates how access of patients with limited resources to needed drugs can be improved by interference with physiological drug elimination.
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Affiliation(s)
- A Iyengar
- Division of Pediatric Nephrology, St John's Medical College Hospital, Bangalore, India
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Iyengar A, Goud BR, Kamath N, Phadke KD, Kasthuri A. Feasibility of screening for urinary abnormalities as a part of school health appraisal. Indian J Nephrol 2012; 22:235-6. [PMID: 23087572 PMCID: PMC3459541 DOI: 10.4103/0971-4065.98807] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- A Iyengar
- Division of Pediatric Nephrology, Department of Pediatrics, St. John's Medical College, Bangalore, India
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Rao S, Shenoy R, Kamath N, Rao S. Unusual Presentation of Duodenal Dieulafoy’s Lesion in a Toddler. JNMA J Nepal Med Assoc 2012. [DOI: 10.31729/jnma.362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Dieulafoy’s lesion is a rare cause of massive upper gastrointestinal haemorrhage in any age. It predominantly occurs in the proximal stomach. We report on a child who presented with massive rectal haemorrhage and a clear nasogastric aspirate due toduodenal Dieulafoy’s lesion.
Keywords: clear nasogastric aspirate; hematemesis; massive rectal haemorrhage; vascular malformation
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Anstey A, McAteer H, Kamath N, Percival F. Extending psychosocial assessment of patients with psoriasis in the UK, using a self-rated, web-based survey. Clin Exp Dermatol 2012; 37:735-40. [DOI: 10.1111/j.1365-2230.2012.04457.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Rao S, Shenoy R, Kamath N, Rao S. Unusual presentation of duodenal Dieulafoy's lesion in a toddler. JNMA J Nepal Med Assoc 2012; 52:133-134. [PMID: 23591174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023] Open
Abstract
Dieulafoy's lesion is a rare cause of massive upper gastrointestinal haemorrhage in any age. It predominantly occurs in the proximal stomach. We report on a child who presented with massive rectal haemorrhage and a clear nasogastric aspirate due to duodenal Dieulafoy's lesion.
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Affiliation(s)
- S Rao
- Department of Pediatrics, K.S.Hegde Medical Academy, Mangalore, India
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Abstract
Sodium retention is the hallmark of idiopathic nephrotic syndrome (INS). Sodium retention could be secondary to activation of renin-angiotensin-aldosterone axis or due to an intrinsic activation of Na(+)K(+) ATPase in the cortical collecting duct. Urine potassium/urine potassium + urine sodium (UK(+)/UK(+) + UNa(+)) is a surrogate marker for aldosterone activity and can be useful in differentiating primary sodium retention from secondary sodium retention in children with INS. This was a cross-sectional study of children with INS, presenting to our center from June 2007 to June 2008. Children were categorized into those with steroid responsive and steroid nonresponsive nephrotic syndrome. One hundred and thirty-four children with nephrotic syndrome were analyzed. The FeNa(+) was significantly lower during relapse than in remission but no such difference was observed with UK(+)/UK(+) + UNa(+). The values of FeNa(+) and UK(+)/UK(+) + UNa(+) across various categories of nephrotic syndrome were similar. Correlating FeNa(+) and UK(+)/UK(+) + UNa(+) with cut-off of 0.5 and 60%, respectively, we found 50% of steroid responsive children and 36% of steroid nonresponders having a corresponding UK(+)/UK(+) + UNa(+) of <60% along with low FeNa(+) of <0.5%, favoring primary sodium retention. Urinary indices did not vary with the type of steroid response. In early relapse, the urinary indices revealed an overlap of both primary and secondary sodium retention in most stable edematous children with nephrotic syndrome.
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Affiliation(s)
- A. A. Iyengar
- Department of Pediatrics, Children's Kidney Care Center, St. John's Medical College Hospital, Bangalore, India
| | - N. Kamath
- Department of Pediatrics, Children's Kidney Care Center, St. John's Medical College Hospital, Bangalore, India
| | - A. Vasudevan
- Department of Pediatrics, Children's Kidney Care Center, St. John's Medical College Hospital, Bangalore, India
| | - K. D. Phadke
- Department of Pediatrics, Children's Kidney Care Center, St. John's Medical College Hospital, Bangalore, India
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Alexander E, Pinto J, Pal GS, Kamath N, Kuruvilla M. Disease concomitance in psoriasis: a clinical study of 61 cases. Indian J Dermatol Venereol Leprol 2001; 67:66-8. [PMID: 17664710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Sixty-one patients with psoriasis were studied for concomitant diseases and compared with 61 age and sex-matched controls. Concomitant cutaneous diseases most often seen with psoriasis were lichen simplex chronicus (16.3%), verruca vulgaris (9.8%) and me Iasina (4.9%). Of the systemic disorders, diabetes showed the highest frequency (13.1%) followed by hypertension (8.1%). Two patients had HIV infection (3.2%). Both the patients had severe and atypical lesions.
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Affiliation(s)
- E Alexander
- Department of Skin and STD, Kasturba Medical Collge, Mangalore. Karnataka-575 001, India
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Constantinou AI, Kamath N, Murley JS. Genistein inactivates bcl-2, delays the G2/M phase of the cell cycle, and induces apoptosis of human breast adenocarcinoma MCF-7 cells. Eur J Cancer 1998; 34:1927-34. [PMID: 10023317 DOI: 10.1016/s0959-8049(98)00198-1] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The aim of this study was to identify the molecular mechanism of action of the isoflavone, genistein. Genistein at 0.15 mM caused MCF-7 apoptotic cell death, which was accompanied by cell cycle delay in the G2/M phase. Twenty-four hours post-treatment, 47.3% of the MCF-7 cells accumulated at G2/M, compared with 19.9% in the untreated controls. At 0.15 mM, genistein caused an increase in the steady-state levels of the wild-type tumour suppressor p53, which was attributed to stabilising the tumour suppressor protein, since p53 mRNA levels did not increase. Prior to the upregulation of p53, which became evident within 6 h of genistein treatment, there was increased bcl-2 phosphorylation at 30 min post-treatment. Although early changes (30-120 min) in the phosphotyrosine peptide patterns were not detected, after 24h, genistein inhibited phosphorylation of several peptides. These results suggest that genistein's dual roles of protein tyrosine kinase inhibitor and topoisomerase II inhibitor are essential for the initiation of apoptosis.
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Affiliation(s)
- A I Constantinou
- Department of Surgical Oncology, College of Medicine, University of Illinois at Chicago 60612, USA
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Abraham S, Kamath N, Pai GS, Pinto J. Nail changes in systemic diseases : A clinical study of 435 cases. Indian J Dermatol Venereol Leprol 1998; 64:144-145. [PMID: 20921746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Nail changes often are reflectors of an internal disease. Four hundred and thirty-five patients admitted in the Medical, Surgical and Obstetric and Gynaecology wards were studied. Nail changes were seen in 134 which included clubbing (21.3%) longitudinal melanonychia (17.2%) and platonychia (14.2%). In patients with HIV associated pulmonary tuberculosis, clubbing was associated with an unique red "crescent sign".
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Affiliation(s)
- S Abraham
- Department of Dermatology and Venereology, Wenlock District Hospital, Mangalore - 575 001, India
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Patel N, Kamath N, Smith CE, Pinchak AC, Hagen JH. Intubating conditions and neuromuscular block after divided dose mivacurium or single dose rocuronium. Can J Anaesth 1997; 44:49-53. [PMID: 8988824 DOI: 10.1007/bf03014324] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
PURPOSE To evaluate the tracheal intubating conditions and neuromuscular blocking characteristics of divided dose mivacurium or single dose rocuronium. METHODS Thirty-two patients undergoing elective surgery were studied. Anaesthesia was with propofol 2 mg.kg-1, followed by an infusion of 150 micrograms.kg-1.min.1. Patients were randomized to receive either mivacurium-0.15 mg.kg-1 followed 30 sec later by 0.1 mg.kg-1, or rocuronium- 0.9 mg.kg-1, followed 30 sec later by placebo. Tracheal intubating conditions were assessed 90 sec after the initial dose of relaxant by an anaesthetists who was unaware of patient group. The electromyographic (EMG) response of the first dorsal interosseus muscle to ulnar nerve train-of-four was measured. RESULTS Successful tracheal intubation was performed in all patients after both mivacurium and rocuronium. Intubating conditions (jaw relaxation, open visible vocal cords) were judged to be good-excellent in all but one patient before insertion of the tracheal tube. However, patients receiving mivacurium were more likely to experience coughing and bucking after tracheal tube insertion (10/16 patients) than those receiving rocuronium (3/16 patients, P < 0.05). No patient in the rocuronium group experienced moderately vigorous coughing and bucking after insertion of the tracheal tube vs six patients in the mivacurium group (P < 0.05). Time to 10 and 25% recovery of neuromuscular function was faster (P < 0.05) after divided dose mivacurium (20 +/- 1 and 23 +/- 1 min, respectively) than after rocuronium (45 +/- 5 and 57 +/- 8 min, respectively). CONCLUSION The results suggest that, during conditions of the study, divided dose mivacurium is not recommended for a 90-sec tracheal intubation in patients where moderate coughing and bucking is deemed unacceptable.
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Affiliation(s)
- N Patel
- Department of Anesthesiology, Case Western Reserve University, Cleveland, Ohio 44109, USA
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Constantinou AI, Vaughan AT, Yamasaki H, Kamath N. Commitment to erythroid differentiation in mouse erythroleukemia cells is controlled by alterations in topoisomerase II alpha phosphorylation. Cancer Res 1996; 56:4192-9. [PMID: 8797591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
To explore the program of cell differentiation in Friend murine erythroleukemia (MEL) cells, we used three clonal variants: phorbol 12-myristate 13-acetate (PMA)-hypersensitive TS-19-101, PMA-resistant TR19-9, and hexamethylene bis-acetamide (HMBA)- and PMA-resistant DS19/R1. After treating TS19-101 cells with HMBA, topoisomerase II (topo II) enzymatic activity was dramatically reduced, and cells became terminally differentiated. The initial reduction in activity was soon followed by reduced topo II alpha phosphorylation, but only later did the protein level drop significantly. PMA, which completely blocked HMBA-induced differentiation in TS19-101 cells, increased the phosphorylation of topo II alpha and restored the enzymatic activity to its original levels. Reduced topo II activity and phosphorylation were also evident in HMBA-treated TR19-9 cells. PMA failed to restore topo II activity and phosphorylation to their original levels in TR19-9 cells. Predictably, the topo II activity and phosphorylation of DS19/R1 cells showed little change in response to HMBA or PMA treatment. Structural changes in chromatin became evident in sensitive cells 24 h after HMBA treatment, suggesting that alterations in topo II alpha phosphorylation may control cell differentiation by altering nuclear architecture.
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Affiliation(s)
- A I Constantinou
- University of Illinois at Chicago, College of Medicine, Department of Surgical Oncology 60612, USA.
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Ganapathi R, Constantinou A, Kamath N, Dubyak G, Grabowski D, Krivacic K. Resistance to etoposide in human leukemia HL-60 cells: reduction in drug-induced DNA cleavage associated with hypophosphorylation of topoisomerase II phosphopeptides. Mol Pharmacol 1996; 50:243-8. [PMID: 8700130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Tumor cell resistance to anthracyclines and epipodophyllotoxins can be due to reduced drug accumulation and/or alterations in the activity of topoisomerase II (TOPO II). HL-60 cells selected in 0.05 micrograms/ml doxorubicin (DOX) are 10-fold and > 20-fold resistant to DOX and etoposide (VP-16), respectively. The accumulation of [3H]VP-16 was 2-3-fold lower in the resistant cells (HL-60/DOX 0.05) than in similarly treated parent-sensitive cells (HL-60/S). However, compared with HL-60/S cells, the HL-60/DOX 0.05 cells required > 20-fold higher concentrations of VP-16 to produce equivalent damage to DNA. The reduced formation of VP-16-stabilized DNA cleavable complex in the HL-60/DOX 0.05 cells was not due to differences in the amount of 170-kDa TOPO (alpha) II protein or enzyme catalytic activity between HL-60/S and HL-60/DOX 0.05 cells. Metabolic labeling with [32P]orthophosphoric acid and immunoprecipitation indicated that the level of phosphorylated 170-kDa TOPO II alpha protein in the HL-60-/S cells was 2.2 +/- 0.4-fold higher than that in HL-60/DOX 0.05 cells. Hypophosphorylation (3-fold) of 170-kDa TOPO II protein in HL-60/S cells treated with the calcium chelator 1,2-bis-(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester produced a > 2-fold reduction in VP-16-induced TOPO II-mediated DNA cleavable complex formation. Two-dimensional mapping of phosphopeptides in complete tryptic digests demonstrated that the reduced phosphorylation of the 170-kDa TOPO II alpha in HL-60/DOX 0.05 cells was due to the hypophosphorylation of at least three phosphopeptides characteristic of HL-60/S cells. Thus, the attenuated ability of TOPO II to form drug-stabilized DNA cleavable complex is related to the phosphorylated state of 170-kDa TOPO II, and in HL-60/DOX 0.05 cells, resistance may be related to hypophosphorylation of three phosphopeptides characteristic of HL-60/S cells.
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Affiliation(s)
- R Ganapathi
- Department of Cancer Biology, Cleveland Clinic Foundation, Ohio 44195, USA
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Abstract
The tumor cell growth inhibitory activity of tamoxifen was enhanced significantly by verapamil treatment in an estrogen receptor positive human breast cancer cell line, MCF-7. Treatment of MCF-7 cells with 5 and 10 micrograms/mL verapamil produced a 1.8- and 2.8-fold increase, respectively, in tamoxifen activity. Unlike reversal of multi-drug resistance, the verapamil-mediated increase in tamoxifen activity was not associated with enhanced drug accumulation. Tamoxifen treatment alone or in combination with verapamil did not affect the activity of protein kinase C, an enzyme implicated in the anti-tumor activity of tamoxifen. Addition of 17 beta-estradiol in the cell survival assay system partially abrogated the modulatory effect of verapamil. These data suggest that potentiation of tamoxifen activity by verapamil may involve interaction of this agent with the estrogen receptor. In conclusion, potentiation of tamoxifen activity by calcium channel blockers represents a novel approach for improving the therapeutic results with tamoxifen in women with breast cancer.
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Affiliation(s)
- V Gupta
- Cancer Research Laboratory, Mercy Cancer Center, Mercy Hospital, Pittsburgh, PA 15219
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Kamath N, Grabowski D, Ford J, Ganapathi R. Calmodulin inhibitor trifluoperazine in combination with doxorubicin induces the selection of tumour cells with the multidrug resistant phenotype. Br J Cancer 1993; 67:1203-8. [PMID: 8099806 PMCID: PMC1968516 DOI: 10.1038/bjc.1993.226] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Trifluoperazine (TFP) is effective in modulating DNA damage/repair in doxorubicin (DOX) treated cells. In the present study we have characterised the resistance phenotype of parental sensitive L1210 mouse leukaemia cells (L1210/S) adapted to grow in the presence of 0.017 microns DOX+5 microM TFP (L1210/DT). Although with prolonged exposure, 0.017 microM DOX alone produced < 35% cell kill in L1210/S cells, similar cytotoxicity was achieved at 0.43 microM DOX in L1210/S cells selected in the presence of 0.017 microM DOX+5 microM TFP. L1210/DT cells were > 30-fold resistant to DOX following a 3 h drug exposure in a soft agar colony assay. In contrast, DOX sensitivity in cells adapted to grow in 5 microM TFP alone was comparable to L1210/S cells. Resistance to other inhibitors of topoisomerase II in L1210/DT cells was > 30-fold to etoposide and > 6-fold to amsacrine. The levels of the 170 kDa and 180 kDa isoforms of topoisomerase II in an immunoblot were comparable between the L1210/S and L1210/DT cells. Cross resistance to vincristine in the L1210/DT cells was accompanied by the overexpression of plasma membrane P-glycoprotein. Although a 1.5-2-fold decrease in accumulation of etoposide and DOX was observed in the L1210/DT cells, drug levels for equivalent DNA damage in the alkaline elution assay were > 5-fold higher in the L1210/DT versus L1210/S cells. No abrogation in the modulating effects of TFP on DOX, VP-16 or amsacrine induced cytotoxicity was apparent in the L1210/DT cells. Results suggest that: (a) TFP in combination with low concentrations DOX can induce the selection of cells with the multidrug resistant phenotype; and (b) characteristics of cells selected for resistance to DOX or DOX plus TFP are comparable.
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Affiliation(s)
- N Kamath
- Department of Cancer Biology, Cleveland Clinic Foundation, Ohio 44195
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Kamath N, Grabowski D, Ford J, Kerrigan D, Pommier Y, Ganapathi R. Overexpression of P-glycoprotein and alterations in topoisomerase II in P388 mouse leukemia cells selected in vivo for resistance to mitoxantrone. Biochem Pharmacol 1992; 44:937-45. [PMID: 1356339 DOI: 10.1016/0006-2952(92)90126-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The overexpression of P-glycoprotein (PGP) and alterations in DNA topoisomerase II (TOPO II) were evaluated in mouse leukemia P388 cells selected in vivo for mitoxantrone (MTT) resistance (P388/MTT) and compared to doxorubicin (DOX) resistant (P388/DOX) or vincristine (VCR) resistant (P388/VCR) models. Among a panel of TOPO II inhibitors which included etoposide (VP-16), DOX, MTT and 4'-[(9-acridinyl)-amino]methanesulfon-m-anisidide (m-AMSA), the relative resistance compared to parental sensitive P388/S cells was: P388/DOX greater than P388/MTT greater than P388/VCR. All the resistant sublines exhibited minimal cell kill (less than 20%) at vincristine concentrations greater than 100-fold the IC50 for P388/S cells. In a soft-agar colony-forming assay, the modulation of cytotoxicity in P388/MTT cells by the calmodulin inhibitor trifluoperazine following a 3-hr drug treatment demonstrated a marked potentiation in cell kill with MTT, VP-16, DOX and m-AMSA but not VCR. Immunoblotting data revealed that while PGP was not detectable in P388/S cells, the overexpression of PGP was apparent in P388/MTT cells and the relative expression between the resistant sublines was: P388/DOX greater than P388/MTT greater than P388/VCR. Although the amount and DNA cleavage activity of TOPO II in nuclear extracts from P388/VCR cells were comparable to those in P388/S cells, they were markedly lower in both P388/DOX and P388/MTT cells. However, decatenation activity of TOPO II in nuclear extracts was comparable between the sensitive (P388/S) and resistant sublines (P388/MTT, P388/DOX, and P388/VCR). Results from the present study demonstrated that P388 cells selected for resistance to mitoxantrone exhibit changes in TOPO II and overexpression of PGP similar to P388/DOX cells, while vincristine resistant cells only overexpress PGP. Since therapeutic strategies are primarily designed to interfere with PGP-mediated drug efflux, the choice of agents for modulating resistance in tumors which overexpress PGP versus tumors which overexpress PGP with altered TOPO II could be different.
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Affiliation(s)
- N Kamath
- Research Institute, Cleveland Clinic Foundation, OH 44195
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Ganapathi R, Kamath N, Constantinou A, Grabowski D, Ford J, Anderson A. Effect of the calmodulin inhibitor trifluoperazine on phosphorylation of P-glycoprotein and topoisomerase II: relationship to modulation of subcellular distribution, DNA damage and cytotoxicity of doxorubicin in multidrug resistant L1210 mouse leukemia cells. Biochem Pharmacol 1991; 41:R21-6. [PMID: 1674871 DOI: 10.1016/0006-2952(91)90115-l] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The results from the present study using the sensitive and progressively DOX resistant L1210 model system demonstrated that the effects of TFP are not due to redistribution of DOX to the nucleus, and modulation of cytotoxicity is related to effects on DOX-induced DNA strand breaks. Although TFP affects phosphorylation of PGP and TOPO II (R2 greater than R1), the comparable DNA strand breaks at lower DOX levels with TFP in the resistant sublines suggest that modulation of TOPO II function related to drug-induced DNA damage by calmodulin-mediated events may be an important mode of action.
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Affiliation(s)
- R Ganapathi
- Research Institute, Cleveland Clinic Foundation, OH 44195
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Kamath N, Grabowski D, Ford J, Drake F, Kerrigan D, Pommier Y, Ganapathi R. Trifluoperazine modulation of resistance to the topoisomerase II inhibitor etoposide in doxorubicin resistant L1210 murine leukemia cells. Cancer Commun (Lond) 1991; 3:37-44. [PMID: 1995027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Murine leukemia L1210 cells selected for progressive resistance to doxorubicin (DOX) display both the multidrug resistant (MDR) phenotype and reductions in drug induced topoisomerase II-mediated DNA cleavage in nuclear extracts (Ganapathi, R.; Grabowski, D.; Ford, J.; Heiss, C.; Kerrigan, D.; Pommier, Y., Cancer Commun. 1:217-224; 1989). The present study was performed to characterize the results of exposure of the sensitive (S) and progressively DOX-resistant (10-fold, R1, and 40-fold, R2) L1210 cells to the topoisomerase II inhibitor, etoposide, and to investigate the modulating effects of the calmodulin inhibitor, trifluoperazine (TFP). Immunoblotting experiments indicated no apparent decrease in the p170 or p180 isoforms of topoisomerase II in the resistant sublines versus parental sensitive cells. Cross-resistance to etoposide (VP-16) was similar to that of DOX (10- and 40-fold). A non-cytotoxic concentration of 5 microM TFP enhanced cell kill 1.5- fold in the sensitive and 3- to 5-fold in the progressively DOX-resistant cells. Accumulation of VP-16 was 30% to 50% lower in the resistant sublines versus similarly treated sensitive cells, and a marked enhancement of drug uptake in the presence of TFP was observed in the sensitive but not in the resistant cells exposed to equivalent extracellular levels of VP-16. Although equimolar concentrations of VP-16 produced fewer DNA single strand breaks (SSB) and DNA protein crosslinks (DPC) in the resistant versus sensitive cells, similar DNA damage was apparent when S and R1, but not R2, cells were treated at VP-16 concentrations that produced equivalent cell death.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- N Kamath
- Research Institute, Cleveland Clinic Foundation, Ohio 44195
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