Combination therapy with pazopanib and tivantinib modulates VEGF and c-MET levels in refractory advanced solid tumors.

The vascular endothelial growth factor (VEGF)/VEGFR and hepatocyte growth factor (HGF)/c-MET signaling pathways act synergistically to promote angiogenesis. Studies indicate VEGF inhibition leads to increased levels of phosphorylated c-MET, bypassing VEGF-mediated angiogenesis and leading to chemoresistance. We conducted a phase 1 clinical trial with 32 patients with refractory solid tumors to evaluate the safety, pharmacokinetics, and pharmacodynamics of combinations of VEGF-targeting pazopanib and the putative c-MET inhibitor ARQ197 (tivantinib) at 5 dose levels (DLs). Patients either took pazopanib and tivantinib from treatment initiation (escalation phase) or pazopanib alone for 7 days, with paired tumor sampling, prior to starting combination treatment (expansion phase). Hypertension was the most common adverse event. No more than 1 dose limiting toxicity (DLT) occurred at any DL, so the maximum tolerated dose (MTD) was not determined; DL5 (800 mg pazopanib daily and 360 mg tivantinib BID) was used during the expansion phase. Twenty of 31 evaluable patients achieved stable disease lasting up to 22 cycles. Circulating VEGF, VEGFR2, HGF, and c-MET levels were assessed, and only VEGF levels increased. Tumor c-MET levels (total and phosphorylated) were determined in paired biopsies before and after 7 days of pazopanib treatment. Total intact c-MET decreased in 6 of 7 biopsy pairs, in contrast to previously reported c-MET elevation in response to VEGF inhibition. These results are discussed in the context of our previously reported analysis of epithelial-mesenchymal transition in these tumors.

Sternocleidomastoid flap for pedicled reconstruction in head & neck surgery- revisiting the anatomy and technique.

BACKGROUND: Previous studies on sternocleidomastoid flaps, have defined the importance of preserving sternocleidomastoid (SCM) branch of superior thyroid artery (STA). This theory drew criticism, as this muscle is known to be a type II muscle, i.e., the muscle has one dominant pedicle (branches from the occipital artery at the superior pole) and smaller vascular pedicles entering the belly of muscle (branches from STA and thyrocervical trunk) at the middle and lower pole respectively. It was unlikely for the SCM branch of STA to supply the upper and lower thirds of the muscle. We undertook a cadaveric angiographic study to investigate distribution of STA supply to SCM muscle. METHODS: It is a cross-sectional descriptive study on 10 cadaveric SCM muscles along with ipsilateral STA which were evaluated with angiography using diatrizoate (urograffin) dye. Radiographic films were interpreted looking at the opacification of the muscle. Results were analyzed using frequency distribution and percentage. RESULTS: Out of ten specimens, near complete opacification was observed in eight SCM muscle specimens. While one showed poor uptake in the lower third of the muscle, the other showed poor uptake in the upper third segment of muscle. CONCLUSION: Based on the above findings we suggest to further investigate sternocleidomastoid muscle as a type III flap, as the STA branch also supplies the whole muscle along with previously described pedicle from occipital artery. However, this needs to be further corroborated intra-operatively using scanning laser doppler. This also explains better survival rates of superior thyroid artery based sternomastoid flaps.

Real time detection and quantification of Epstein Barr virus in different grades of oral gingivitis and periodontitis patients.

BACKGROUND: Periodontal diseases are of microbial etiology and are globally causing loss of teeth in adult population. Many severe oral diseases have been recently associated to Herpes viruses, of which Epstein Barr Virus (EBV) and human cytomegalovirus (HCMV) have been indicated in the etiology of periodontal diseases. AIM: The purpose of the study was to compare the effect of EBV in different types of periodontal diseases namely acute gingivitis, chronic gingivitis, acute and chronic, localized and generalized aggressive (juvenile) periodontitis and apical periodontitis. MATERIAL AND METHOD: 70 individuals were included in this study. Supragingival plaque and plaque from two deepest sites of the periodontal pockets were collected then stored at 70° c and prepared for nucleic acid extraction. For EBV detection, DNA were extracted from the plaque samples with the QIAamp DNA mini kit. Q-PCR was performed by targeting the non-polymorphic Epstein-Barr nuclear antigen-1 (EBNA-1) gene using Corbett Research 6000 Q-PCR instrument and Rotor gene 6000 software. RESULTS: Overall prevalence of EBV in the disease group was 60% (27/45 patients) as compared to only 8% (4/25 people) in the normal population. The mean copy number of EBV DNA was found to be significantly higher in periodontitis (2234 ± 1811.34) when compared to gingivitis (554 ± 537.64, p = .001) and normal patients (370 ± 161.03, p < .001). CONCLUSION: Here, we found that the prevalence of EBV as well as copy number of EBV was significantly higher in periodontitis patients as compared to gingivitis patients or normal population.

A multianalytical approach to evaluate the association of 55 SNPs in 28 genes with obesity risk in North Indian adults.

OBJECTIVES: The aim of the study was to investigate the association of 55 SNPs in 28 genes with obesity risk in a North Indian population using a multianalytical approach. METHODS: Overall, 480 subjects from the North Indian population were studied using strict inclusion/exclusion criteria. SNP Genotyping was carried out by Sequenom Mass ARRAY platform (Sequenom, San Diego, CA) and validated Taqman® allelic discrimination (Applied Biosystems® ). Statistical analyses were performed using SPSS software version 19.0, SNPStats, GMDR software (version 6) and GENEMANIA. RESULTS: Logistic regression analysis of 55 SNPs revealed significant associations (P < .05) of 49 SNPs with BMI linked obesity risk whereas the remaining 6 SNPs revealed no association (P > .05). The pathway-wise G-score revealed the significant role (P = .0001) of food intake-energy expenditure pathway genes. In CART analysis, the combined genotypes of FTO rs9939609 and TCF7L2 rs7903146 revealed the highest risk for BMI linked obesity. The analysis of the FTO-IRX3 locus revealed high LD and high order gene-gene interactions for BMI linked obesity. The interaction network of all of the associated genes in the present study generated by GENEMANIA revealed direct and indirect connections. In addition, the analysis with centralized obesity revealed that none of the SNPs except for FTO rs17818902 were significantly associated (P < .05). CONCLUSIONS: In this multi-analytical approach, FTO rs9939609 and IRX3 rs3751723, along with TCF7L2 rs7903146 and TMEM18 rs6548238, emerged as the major SNPs contributing to BMI linked obesity risk in the North Indian population.

Analysis of MC4R rs17782313, POMC rs1042571, APOE-Hha1 and AGRP rs3412352 genetic variants with susceptibility to obesity risk in North Indians.

BACKGROUND: Obesity is a multi-factorial disorder influenced by genetic and environmental factors. The physiological pathways associated with obesity are complex and involve several genes. AIM: The aim of this survey is to evaluate the association of genetic variants of melanocortin-4-receptor (MC4R), pro-opiomelanocortin (POMC), apolipoprotein E (APOE) and agouti-related protein (AGRP) with obesity in the North Indian population. METHODS: MC4R rs17782313, POMC rs1042571, APOE-Hha1 and AGRP rs3412352 polymorphisms were investigated for their association in 396 obese individuals with BMI ≥ 30 kg/m(2) and 300 healthy non-obese individuals with BMI < 30 kg/m(2). Genotyping was performed using Taqman probes and PCR-RFLP methods. Single locus logistic regression analysis was conducted using (SPSS), ver.19 and PLINK software Version 1.01 and high order genetic interactions associated with obesity risk were analysed using MDR software (version 2.3.0.2). RESULTS: The genotypes of MC4R rs17782313, POMC rs1042571 and APOE-Hha1 were significantly associated with obese individuals (BMI ≥ 30 kg/m(2)) when compared with non-obese individuals (BMI < 30 kg/m(2)). No association of AGRP rs34123523 was seen with obesity. CONCLUSIONS: The best interaction model for predicting obesity risk by MDR analysis was the three factor model including POMC (C > T), MC4R (T > C) and APOE (Hha1) polymorphisms. Genetic variants in MC4R, POMC and APOE genes might play significant roles in predisposing obesity (BMI ≥ 30 kg/m(2)) in the North Indian population.

Association of FTO and IRX3 genetic variants to obesity risk in north India.

BACKGROUND: Obesity is an increasingly important health problem worldwide as well as in developing countries like India. Recent genetic studies suggest that obesity associated FTO and IRX3 are functionally linked and many effects due to genetic variants in FTO gene act through IRX3. AIM: To evaluate the association of FTO and IRX3 genetic variants towards obesity risk. SUBJECTS AND METHODS: North Indian individuals categorised as non-obese (BMI < 30 kg/m(2)) and obese (BMI ≥ 30 kg/m(2)) were selected. FTO rs8050136, rs1421085, rs9939609, rs17817449 and IRX3 rs3751723 were genotyped by means of validated Taqman® allelic discrimination to evaluate their association with obesity by means of single locus logistic regression by SPSS ver. 19 and multi-locus linkage and haplotype analysis by SNPStats and gene-gene interaction with Generalised Multifactor Dimensionality Reduction (GMDR) ver.6. RESULTS: In single locus analysis, FTO rs8050136 CA (p = 0.0001; OR (95% CI) = 2.4 (1.7-3.4) and AA (p = 0.0001; OR (95% CI) = 3.1 (1.9-5.2); FTO rs1421085 TA (p = 0.0001; OR (95% CI) = 2.1 (1.4-3.0) and AA (p = 0.0001; OR (95% CI) = 3.0 (1.8-5.0); FTO rs9939609 TC (p = 0.0001; OR (95% CI) = 2.1 (1.5-3.1) and CC (p = 0.0001; OR (95% CI) = 4.2 (2.5-7.3) along with TG (p = 0.001; OR (95% CI) = 2.1 (1.3-3.2) and GG (p = 0.021; OR (95% CI) = 3.8 (1.2-11.8) genotypes of FTO rs17817449 with GT (p = 0.0001; OR (95% CI) = 2.1 (1.5-3.1) and TT (p = 0.012; OR (95% CI) = 3.3 (1.8-3.6) genotypes of IRX3 rs3751723 were significantly associated with obesity. In multi-locus analysis, SNPs of FTO and IRX3 were in strong linkage disequilibrium and in haplotype and GMDR analysis the SNPs were significantly associated with obesity risk (p < 0.05). CONCLUSION: This is the first study to reveal that genetic variants of both FTO and IRX3 genes are in high linkage disequilibrium (LD) and are associated with obesity risk in North Indians.

Genetics of Obesity.

Numerous classical genetic studies have proved that genes are contributory factors for obesity. Genes are directly responsible for obesity associated disorders such as Bardet-Biedl and Prader-Willi syndromes. However, both genes as well as environment are associated with obesity in the general population. Genetic epidemiological approaches, particularly genome-wide association studies, have unraveled many genes which play important roles in human obesity. Elucidation of their biological functions can be very useful for understanding pathobiology of obesity. In the near future, further exploration of obesity genetics may help to develop useful diagnostic and predictive tests for obesity treatment.

ENU mutation mapped to a distal region of chromosome 11 is a major determinant of bone size.

Using a phenotype driven n-ethyl-nitrosourea (ENU) screen in growth hormone-deficient mice, we have identified a mutant (named 14104) that exhibited a smaller bone size. Phenotype measurements by microcomputed tomography revealed that mutant mice exhibited a 43 and 34% reduction in tissue area and bone area, respectively at the femur middiaphysis. Dynamic histomorphometry revealed a 30 and 15% lower bone formation rate at the periosteal and endosteal surface, respectively. Breaking strength of the femur was reduced by 30% in the mutant mice. To determine if the 14104 locus is involved in a mechanical loading signaling pathway, the skeletal anabolic response to tibia axial loading was evaluated. The increase in trabecular response in the loaded region was severely compromised by the 14014 mutation. To identify the location of mutation, we performed linkage analysis using 62 polymorphic markers in the B6-DBA/2J F2 mice. The genome-wide linkage analysis identified the location of the mutation to a 72 to 83 cM region on chromosome 11 with peak logarithm of the odds scores of 15 for periosteal circumference at marker D11mit338. Sequence analysis revealed no mutation in the coding region of 11 potential candidate genes. Based on these data and published data on the skeletal phenotype of genes in this region, we concluded that the 109-119 Mb region of chromosome 11 harbors a bone size gene that regulates periosteal bone formation. The mutant strain developed in this study provides an important tool to identify a novel mechanosensitive gene that determines bone size during postnatal development.

Association of apolipoprotein B XbaI gene polymorphism and lipid profile in northern Indian obese.

BACKGROUND: Over the last few decades, obesity, diabetes, and hypertension have become main health evils. The health problems of obesity are well-recognized. However, the fact that all obese individuals are not at the same risk of developing a disease is also recognized. The apolipoprotein B (APOB) plays a central role in lipid metabolism. So we compare the association of APOB XbaI gene polymorphism and lipid profile total in obese north Indian population. MATERIALS AND METHODS: A total of 132 obese (body mass index [BMI] >25 kg/m(2)) and 132 age matched non-obese (BMI ≤ 25 kg/m(2)) subjects were studied after taking detailed clinical profile. Lipid profile in serum/plasma was done using commercial kits. Genetic analysis of APOB XbaI was done using Polymerase Chain Reaction-Restriction Fragment Leanth polymorphism (PCR-RFLP). STATISTICAL ANALYSIS: Statistical analysis was performed by Statistical Package for the Social Sciences (SPSS) (version 11.5) software (IBM Corporation). All continuous variables were expressed as mean ± SD and tested by analysis of variance test. Comparisons of categorical variables were assessed using χ(2) tests or Fisher's exact test. P < 0.05 was considered as significant. RESULTS: Analysis showed that obese subjects had significantly higher value of the waist-to-hip ratio, blood pressure (systolic and diastolic), and lipid profile. In APOB XbaI gene polymorphism, we did not find significant differences in genotype or allele frequencies. Moreover, none of the studied metabolic parameters (lipid profile) showed any association with the gene polymorphism. CONCLUSIONS: Study reveals no considerable association of APOB XbaI gene polymorphism with obesity and lipid profile in north Indians.

Comparative analysis of cheiloscopy, pulpal tissue and fingerprint for gender identification.

Background: The most important step in identifying an unknown person is determining one's gender and as a dentist, the oral tissues are potential sources of information in this aspect. A study was carried out to assess and evaluate the accuracy of cheiloscopy, pulp tissue, and fingerprints in determining gender. Material and Methods: A study comprising of 160 individuals (80 males and 80 females) was conducted. After obtaining informed written consent and recording their bio-data; lip prints, and fingerprints were recorded. The patients' extracted tooth was collected, their pulp extirpated, for assessment of the Barr body. Results: We found that every lip pattern was unique and hence can be used to identify an unknown individual. The occurrence of the Barr body was determined, and all female samples were found to be positive for the existence of the Barr body. In fingerprint patterns, a significant difference was noted between both sexes with ulnar loops and whorl patterns only. A highly significant difference was observed in the fingerprint ridge density between genders. Conclusions: We conclude that the Barr body in pulpal tissue can be considered as the best possible technique for gender determination within the dental tissues. Lip prints did not show any differences in genders and had no role to play in gender determination. Fingerprint ridge density can also be used to determine gender.

Redox phospholipidomics discovers pro-ferroptotic death signals in A375 melanoma cells in vitro and in vivo.

Growing cancer cells effectively evade most programs of regulated cell death, particularly apoptosis. This necessitates a search for alternative therapeutic modalities to cause cancer cell's demise, among them - ferroptosis. One of the obstacles to using pro-ferroptotic agents to treat cancer is the lack of adequate biomarkers of ferroptosis. Ferroptosis is accompanied by peroxidation of polyunsaturated species of phosphatidylethanolamine (PE) to hydroperoxy- (-OOH) derivatives, which act as death signals. We demonstrate that RSL3-induced death of A375 melanoma cells in vitro was fully preventable by ferrostatin-1, suggesting their high susceptibility to ferroptosis. Treatment of A375 cells with RSL3 caused a significant accumulation of PE-(18:0/20:4-OOH) and PE-(18:0/22:4-OOH), the biomarkers of ferroptosis, as well as oxidatively truncated products - PE-(18:0/hydroxy-8-oxo-oct-6-enoic acid (HOOA) and PC-(18:0/HOOA). A significant suppressive effect of RSL3 on melanoma growth was observed in vivo (utilizing a xenograft model of inoculation of GFP-labeled A375 cells into immune-deficient athymic nude mice). Redox phospholipidomics revealed elevated levels of 18:0/20:4-OOH in RSL3-treated group vs controls. In addition, PE-(18:0/20:4-OOH) species were identified as major contributors to the separation of control and RSL3-treated groups, with the highest variable importance in projection predictive score. Pearson correlation analysis revealed an association between tumor weight and contents of PE-(18:0/20:4-OOH) (r = -0.505), PE-18:0/HOOA (r = -0.547) and PE 16:0-HOOA (r = -0.503). Thus, LC-MS/MS based redox lipidomics is a sensitive and precise approach for the detection and characterization of phospholipid biomarkers of ferroptosis induced in cancer cells by radio- and chemotherapy.

Optimization of 1,2,4-Triazole-Based p97 Inhibitors for the Treatment of Cancer.

The AAA+ ATPase p97 (valosin-containing protein, VCP) is a master regulator of protein homeostasis and therefore represents a novel target for cancer therapy. Starting from a known allosteric inhibitor, NMS-873, we systematically optimized this scaffold, in particular, by applying a benzene-to-acetylene isosteric replacement strategy, specific incorporation of F, and eutomer/distomer identification, which led to compounds that exhibited nanomolar biochemical and cell-based potency. In cellular pharmacodynamic assays, robust effects on biomarkers of p97 inhibition and apoptosis, including increased levels of ubiquitinated proteins, CHOP and cleaved caspase 3, were observed. Compound (R)-29 (UPCDC-30766) represents the most potent allosteric inhibitor of p97 reported to date.

Comparative Oncology Assessment of a Novel Inhibitor of Valosin-Containing Protein in Tumor-Bearing Dogs.

Pet dogs with naturally occurring cancers play an important role in studies of cancer biology and drug development. We assessed tolerability, efficacy, and pharmacokinetic/pharmacodynamic relationships with a first-in-class small molecule inhibitor of valosin-containing protein (VCP/p97), CB-5339, administered to 24 tumor-bearing pet dogs. Tumor types assessed included solid malignancies, lymphomas, and multiple myeloma. Through a stepwise dose and schedule escalation schema, we determined the maximum tolerated dose to be 7.5 mg/kg when administered orally on a 4 days on, 3 days off schedule per week for 3 consecutive weeks. Adverse events were minimal and mainly related to the gastrointestinal system. Pharmacokinetic/pharmacodynamic data suggest a relationship between exposure and modulation of targets related to induction of the unfolded protein response, but not to tolerability of the agent. An efficacy signal was detected in 33% (2/6) of dogs with multiple myeloma, consistent with a mechanism of action relating to induction of proteotoxic stress in a tumor type with abundant protein production. Clinical trials of CB-5339 in humans with acute myelogenous leukemia and multiple myeloma are ongoing.

Development and validation of an LC-MS/MS generic assay platform for small molecule drug bioanalysis.

AIM: We developed a generic high-performance liquid chromatography mass spectrometry approach for quantitation of small molecule compounds without availability of isotopically labelled standard. METHODS: The assay utilized 50 µL of plasma and offers 8 potential internal standards (IS): acetaminophen, veliparib, busulfan, neratinib, erlotinib, abiraterone, bicalutamide, and paclitaxel. Preparation consisted of acetonitrile protein precipitation and aqueous dilution in a 96 well-plate format. Chromatographic separation was achieved with a Kinetex C18 reverse phase (2.6 µm, 2 mm x 50 mm) column and a gradient of 0.1 % formic acid in acetonitrile and water over an 8 min run time. Mass spectrometric detection was performed on an AB SCIEX4000QTRAP with electrospray, positive-mode ionization. Performance of the generic approach was evaluated with seven drugs (LMP744, olaparib, cabozantinib, triapine, ixabepilone, berzosertib, eribulin) for which validated assays were available. RESULTS: The 8 IS covered a range of polarity, size, and ionization; eluted over the range of chromatographic retention times; were quantitatively extracted; and suffered limited matrix effects. The generic approach proved to be linear for test drugs evaluated over at least 3 orders of magnitude starting at 1-10 ng/mL, with extension of assay ranges with analyte isotopologue MRM channels. At a bias of less than 16 % and precision within 15 %, the assay performance was acceptable. CONCLUSION: The generic approach has become a useful tool to further define the pharmacology of drugs studied in our laboratory and may be utilized as described, or as starting point to develop drug-specific assays with more extensive performance characterization.

Isoform- and Phosphorylation-specific Multiplexed Quantitative Pharmacodynamics of Drugs Targeting PI3K and MAPK Signaling in Xenograft Models and Clinical Biopsies.

Ras/Raf/MEK/ERK (MAPK) and PI3K/AKT signaling pathways influence several cell functions involved in oncogenesis, making them attractive drug targets. We describe a novel multiplex immunoassay to quantitate isoform-specific phosphorylation of proteins in the PI3K/AKT and MAPK pathways as a tool to assess pharmacodynamic changes. Isoform-specific assays measuring total protein and site-specific phosphorylation levels of ERK1/2, MEK1/2, AKT1/2/3, and rpS6 were developed on the Luminex platform with validated antibody reagents. The multiplex assay demonstrated satisfactory analytic performance. Fit-for-purpose validation was performed with xenograft models treated with selected agents. In PC3 and HCC70 xenograft tumors, the PI3Kß inhibitor AZD8186 suppressed phosphorylation of AKT1, AKT2, and rpS6 for 4 to 7 hours post single dose, but levels returned to baseline by 24 hours. AKT3 phosphorylation was suppressed in PC3 xenografts at all doses tested, but only at the highest dose in HCC70. The AKT inhibitor MK-2206 reduced AKT1/2/3 phosphorylation in SW620 xenograft tumors 2 to 4 hours postdose, and the MEK inhibitor selumetinib reduced MEK1/2 and ERK1/2 phosphorylation by up to 50% and >90%, respectively. Clinical utility was demonstrated by analyzing biopsies from untreated patients with plexiform neurofibromas enrolled in a clinical trial of selumetinib (NCT02407405). These biopsies showed MEK and ERK phosphorylation levels sufficient for measuring up to 90% inhibition, and low AKT and rpS6 phosphorylation. This validated multiplex immunoassay demonstrates the degree and duration of phosphorylation modulation for three distinct classes of drugs targeting the PI3K/AKT and MAPK pathways.

Redox Epiphospholipidome in Programmed Cell Death Signaling: Catalytic Mechanisms and Regulation.

A huge diversification of phospholipids, forming the aqueous interfaces of all biomembranes, cannot be accommodated within a simple concept of their role as membrane building blocks. Indeed, a number of signaling functions of (phospho)lipid molecules has been discovered. Among these signaling lipids, a particular group of oxygenated polyunsaturated fatty acids (PUFA), so called lipid mediators, has been thoroughly investigated over several decades. This group includes oxygenated octadecanoids, eicosanoids, and docosanoids and includes several hundreds of individual species. Oxygenation of PUFA can occur when they are esterified into major classes of phospholipids. Initially, these events have been associated with non-specific oxidative injury of biomembranes. An alternative concept is that these post-synthetically oxidatively modified phospholipids and their adducts with proteins are a part of a redox epiphospholipidome that represents a rich and versatile language for intra- and inter-cellular communications. The redox epiphospholipidome may include hundreds of thousands of individual molecular species acting as meaningful biological signals. This review describes the signaling role of oxygenated phospholipids in programs of regulated cell death. Although phospholipid peroxidation has been associated with almost all known cell death programs, we chose to discuss enzymatic pathways activated during apoptosis and ferroptosis and leading to peroxidation of two phospholipid classes, cardiolipins (CLs) and phosphatidylethanolamines (PEs). This is based on the available LC-MS identification and quantitative information on the respective peroxidation products of CLs and PEs. We focused on molecular mechanisms through which two proteins, a mitochondrial hemoprotein cytochrome c (cyt c), and non-heme Fe lipoxygenase (LOX), change their catalytic properties to fulfill new functions of generating oxygenated CL and PE species. Given the high selectivity and specificity of CL and PE peroxidation we argue that enzymatic reactions catalyzed by cyt c/CL complexes and 15-lipoxygenase/phosphatidylethanolamine binding protein 1 (15LOX/PEBP1) complexes dominate, at least during the initiation stage of peroxidation, in apoptosis and ferroptosis. We contrast cell-autonomous nature of CLox signaling in apoptosis correlating with its anti-inflammatory functions vs. non-cell-autonomous ferroptotic signaling facilitating pro-inflammatory (necro-inflammatory) responses. Finally, we propose that small molecule mechanism-based regulators of enzymatic phospholipid peroxidation may lead to highly specific anti-apoptotic and anti-ferroptotic therapeutic modalities.

Clinical Evolution of Epithelial-Mesenchymal Transition in Human Carcinomas.

The significance of the phenotypic plasticity afforded by epithelial-mesenchymal transition (EMT) for cancer progression and drug resistance remains to be fully elucidated in the clinic. We evaluated epithelial-mesenchymal phenotypic characteristics across a range of tumor histologies using a validated, high-resolution digital microscopic immunofluorescence assay (IFA) that incorporates ß-catenin detection and cellular morphology to delineate carcinoma cells from stromal fibroblasts and that quantitates the individual and colocalized expression of the epithelial marker E-cadherin (E) and the mesenchymal marker vimentin (V) at subcellular resolution ("EMT-IFA"). We report the discovery of ß-catenin+ cancer cells that coexpress E-cadherin and vimentin in core-needle biopsies from patients with various advanced metastatic carcinomas, wherein these cells are transitioning between strongly epithelial and strongly mesenchymal-like phenotypes. Treatment of carcinoma models with anticancer drugs that differ in their mechanism of action (the tyrosine kinase inhibitor pazopanib in MKN45 gastric carcinoma xenografts and the combination of tubulin-targeting agent paclitaxel with the BCR-ABL inhibitor nilotinib in MDA-MB-468 breast cancer xenografts) caused changes in the tumor epithelial-mesenchymal character. Moreover, the appearance of partial EMT or mesenchymal-like carcinoma cells in MDA-MB-468 tumors treated with the paclitaxel-nilotinib combination resulted in upregulation of cancer stem cell (CSC) markers and susceptibility to FAK inhibitor. A metastatic prostate cancer patient treated with the PARP inhibitor talazoparib exhibited similar CSC marker upregulation. Therefore, the phenotypic plasticity conferred on carcinoma cells by EMT allows for rapid adaptation to cytotoxic or molecularly targeted therapy and could create a form of acquired drug resistance that is transient in nature. SIGNIFICANCE: Despite the role of EMT in metastasis and drug resistance, no standardized assessment of EMT phenotypic heterogeneity in human carcinomas exists; the EMT-IFA allows for clinical monitoring of tumor adaptation to therapy.

A chemical mutagenesis screen to identify modifier genes that interact with growth hormone and TGF-beta signaling pathways.

We describe a phenotype-driven mutagenesis screen in which mice carrying a targeted mutation are bred with ENU-treated males in order to provide a sensitized system for detecting dominant modifier mutations. The presence of initial mutation renders the screening system more responsive to subtle changes in modifier genes that would not be penetrant in an otherwise wild type background. We utilized two mutant mouse models: 1) mice carrying a mutation in growth hormone releasing hormone receptor (Ghrhr) (denoted 'lit' allele, Ghrhr(lit)), which results in GH deficiency; and 2) mice lacking Smad2 gene, a signal transducer for TGF-beta, an important bone growth factor. The Smad2(-/-) mice are lethal and Ghrhr(lit/lit) mice are dwarf, but both Smad2(+/-) and Ghrhr(lit/)(+) mice exhibit normal growth. We injected 6-7 weeks old C57BL/6J male mice with ENU (100 mg/kg dose) and bred them with Ghrhr(lit/)(+) and Smad2(+/-) mice. The F1 mice with Ghrhr(lit/)(+) or Smad2(+/-) genotype were screened for growth and skeletal phenotypes. An outlier was identified as >3 SD units different from wild type control (n=20-30). We screened about 100 F1 mice with Ghrhr(lit/)(+) and Smad2(+/-) genotypes and identified nine outliers. A backcross established heritability of three mutant lines in multiple generations. Among the phenotypic deviants, we have identified a mutant mouse with 30-40% reduced bone size. The magnitude of the bone size phenotype was amplified by the presence of one copy of the disrupted Ghrhr gene as determined by the 2-way ANOVA (p<0.02 for interaction). Thus, a new mouse model has been established to identify a gene that interacts with GH signaling to regulate bone size. In addition, the sensitized screen also demonstrated higher recovery of skeletal phenotypes as compared to that obtained in the classical ENU screen in wild type mice. The discovery of mutants in a selected pathway will provide a valuable tool to not only to discover novel genes involved in a particular process but will also prove useful for the elucidation of the biology of that process.

The Association of a Rare Variant of -93, -53 Promoter Gene Polymorphisms of Lipoprotein Lipase gene with Obesity and Insulin Resistance.

OBJECTIVES: Obesity increases the risk of numerous chronic diseases. Obesity is classified clinically using body mass index (BMI), waist-to-hip ratio, and body fat percentage. The lipoprotein lipase (LPL) gene has been linked to lipoprotein metabolism and obesity. We performed a case-control study to determine the association between LPL gene polymorphisms and obesity-associated phenotypes such as insulin resistance (IR). METHODS: We examined the different LPL gene variants for association in 642 individuals segregated by BMI and IR. Genotyping of the LPL gene -93 and -53 promoter gene polymorphisms were analyzed using polymerase chain reaction-restriction fragment length polymorphism. RESULTS: A substantial association was observed for -93 gene polymorphism of the LPL gene with obesity, while -53 promoter gene polymorphism showed association with IR. CONCLUSIONS: We found a significant association between -93 and -53 promoter gene polymorphisms of the LPL gene with obesity and associated phenotypes in the studied population.