Quercetin inhibits truncated isoform of dopamine-and cAMP-regulated phosphoprotein as adjuvant treatment for trastuzumab therapy resistance in HER2-positive breast cancer

Trastuzumab resistance is one of the causes of poor prognosis in patients with human epidermal growth factor receptor 2(HER2)-positive(HER2+)breast cancer(BC).The truncated isoform of dopamine-and cAMPregulated phosphoprotein(t-DARPP)has been reported to be involved in trastuzumab therapy resistance and promoting tumor progression.To evaluate the t-DARPP expression in BC,paired tumors and surrounding normal tissues were analyzed by real-time polymerase chain reaction and confirmed higher DARPP-32 kDa family mRNA expression in HER2+BC tumor tissues.We established 2 patient-derived xenografts(PDX)mice models to test the efficacy of trastuzumab,named model 1(non-responder)and model 2(responder).t-DARPP and p95-HER2 protein-protein interactions were detected in PDX tumor tissue from non-responders using Förster resonance energy transfer assays.Instead,there is no response from the responder.Furthermore,mechanistic studies using transwell and western blot assays demonstrated that t-DARPP could upregulate epithelial-mesenchymal transition signaling proteins,enhance p95-HER2 expression and promote cell migration.We found that quercetin effectively reduced t-DARPP expression in HER2+BC cells.In t-DARPP ShRNA-suppressed cells,quercetin synergistically enhanced trastuzumab-induced apoptotic cell death and G2/M phase arrest.In conclusion,the combination of quercetin and trastuzumab treatment by targeting t-DARPP in HER2+BC patients has the potential as a biomarker for mitigating drug resistance.

Phosphorus Starvation-induced Expression of Leaf Acid Phosphatase Isoforms in Soybean

Leaf acid phosphatase (APase) activities of 274 soybean genotypes were surveyed under field conditions with two levels of P supplies, and a nutrient solution culture experiment with eight selected genotypes was subsequently conducted under greenhouse conditions to further characterize APase activity and its isoform expression induced by P starvation. Results from the field experiment showed that there was a great genotypic variation for leaf APase activity among the tested soybean genotypes from different origins, and APase activity in many of the tested genotypes (about 60%) was generally increased in the treatment without P fertilizer addition. Results from the nutrient solution culture experiment showed that APase activity in all the eight tested genotypes was generally enhanced by P starvation. Six isoforms of APases were detected in isoelectric focusing gels with samples from both young and old leaves. The activity of all the six isoforms was increased by P starvation, but no new APase isoform was induced. Our results suggest that leaf APase activity could serve as an enzymatic indicator of P starvation for soybean; the increase in leaf APase activity under low P stress was mainly caused by the increase in the activity of existing isoforms but not by the induction of new isoforms.

Differential Expression of PKC Isoforms and Their Tumoricidal Activity in Two Macrophage Cell Lines: Involvement of Nitric Oxide-dependent Mechanisms

Objective: To investigate the role of PKC isoforms in the regulation of LPS-triggered tumoricidal activity in macrophages and further elucidate its signal mechanisms. Methods: Two macrophage cell lines (P388D1 and RAW264.7) were stimulated by LPS alone, or with long-term of PMA pretreatment. Then cytotoxicities to P815 cells (by MTT assay) and IL-1, TNF- (by ELISA) and nitric oxide (NO) production (by Griess reagent) in supernatants were measured. Western blot for PKC isoforms after long-term PMA pretreatment was analyzed. Results: RAW264.7 cells were stimulated with LPS to kill target tumor cells P815, whereas P388D1 cells failed to develop such an ability. Down-regulation of PKC isoforms by chronic treatment with PMA significantly inhibited the LPS-induced cytotoxicity in RAW264.7 cells. In unstimulated state, Western blotting with rabbit antiserum specific for the PKC, 1, 2, or showed all 5 isoforms were detected in P388D1 cells, while only PKC, PKC1 and PKC were detected in RAW264.7 cells. Exposure of the cells to long-term of PMA treatment significantly down-regulated the expression of PKC, PKC1 and PKC in RAW264.7 cells. But in P388D1 cells, although PKC, PKC and PKC were down-regulated, the expression of PKC1 and PKC2 could not be regulated. Comparing with LPS-induced IL-1, TNF- and NO production by the two macrophage cell lines, P388D1 failed to produce NO. In RAW264.7 cells, LPS-induced NO production and antitumor activity was attenuated by the addition of L-NAME, an iNOS inhibitor. Conclusion: The results indicated a critical role of PKC in LPS-induced antitumor activity and this cytotoxicity is mainly due to PKC- mediated NO production by RAW264.7 cells, but not a direct cytotoxic activity.

Analysis of Gene Expression of Seven Isoforms of ADP-glucose Pyrophosphorylase in Rice Endosperm under Different Temperature Conditions

[Objective] This study aimed to analyze the effects of temperature on the expression of AGPase isoform genes in rice endosperm during milk stage. [Method] Different temperature treatments （33 and 25 ℃ of daily mean temperature for high and normal temperature treatments, respectively） and the real-time fluorescence quantitative PCR （ FQPCR） were used to analyze the expression patterns of seven isoforms （AGPS1, AGPS2a, AGPS2b, AGPL1, AGPL2, AGPL3 and AGPL4） of ADPglucose pyrophosphorylase （AGPase） which was the key enzyme in starch synthesis and metabolism in rice endosperm of two rice varieties Teqing and Thai Fragrant Rice. [Result] The AGPase isoforms AGPS2b, AGPL2 and AGPL3 had much higher expression than the other four isoforms, thus they were thought to be the main expression patterns of AGPase in rice endosperm. The relative expressions of AGPL2 was the highest among all the isoforms. The relative expressions of AGPS2b, AGPL2 and AGPL3 were higher in the normal temperature treatment than in the high temperature treatment in both rice varieties. The relative expression of the three enzyme genes in milk stages in Teqing was higher than those in Thai Fragrant Rice under different temperature treatments. [Conclusion] This study provides a theoretical basis for further use of molecular biology techniques to cultivate stable high-quality rice varieties.

Androgen receptor isoforms in human and rat prostate

Aim: To investigate the androgen receptor (AR) isoforms and its variability of expression in human and rat prostatictissues. Methods: Human benign prostatic hyperplasia (BPH) and prostatic cancer tissues were obtained from pa-tients undergoing prostatectomy, and rat ventral prostate was incised 3 days after castration. Forty-one AR-positive BPHspecimens, 3 prostatic cancer specimens, and 6 rat prostates were used. After processing at 4℃, the tissues were ex-amined by means of high resolution isoelectric focusing (IEF) technique to determine their AR isoforms. Results:From the prostatic specimens, 3 types of AR isoforms were detected with pI values at 6.5, 6.0, and 5.3. In humanBPH tissues, 15/41 (36.6%) specimens showed all the three types of isoforms, while 19/41 (46.3%) showed 2 iso-fora at various combinations and 7/41 (17.1%), 1 isoform. For the 3 prostatic cancer specimens, one showed 3 iso-forms, one, 2 isoforms, and the other failed to show any isoform. All rat prostatic tissues showed 2 isoforms at differ-ent combinations. Binding of ~3H-dihydrotestosterone (DHT) to the isoforms was inhibited by the addition of 100-foldexcess of DHT or testosterone, but not progesterone, oestradiol or diethylstilboestrol. Conclusion: AR isoforms aredifferent in different patients. Although their genesis is not clear, the therapeutic implication of the present observationappears to be interesting, that may help clarifying the individual differences in the response to hormonal therapy.(Asian J Androl 2000 Dec; 2: 307-310)

Role of PRMTs in cancer: Could minor isoforms be leaving a mark?

Protein arginine methyltransferases(PRMTs) catalyze the methylation of a variety of protein substrates, many of which have been linked to the development, progression and aggressiveness of different types of cancer. Moreover, aberrant expression of PRMTs has been observed in several cancer types. While the link between PRMTs and cancer is a relatively new area of interest, the functional implications documented thus far warrant further investigations into its therapeutic potential. However, the expression of these enzymes and the regulation of their activity in cancer are still significantly understudied. Currently there are nine main members of the PRMT family. Further, the existence of alternatively spliced isoforms for several of these family members provides an additional layer of complexity. Specifically, PRMT1, PRMT2, CARM1 and PRMT7 have been shown to have alternative isoforms and others may be currently unrealized. Our knowledge with respect to the relative expression and the specific functions of these isoforms is largely lacking and needs attention. Here we present a review of the current knowledge of theknown alternative PRMT isoforms and provide a rationale for how they may impact on cancer and represent potentially useful targets for the development of novel therapeutic strategies.

Characterization of four hemocyanin isoforms in Litopenaeus vannamei

In this study, the gene encoding hemocyanin subunit L, Lv Hc L, was cloned from Litopenaeus vannamei and the genomic organization was characterized. This gene was diverse with many SNPs and also had at least four isoforms, while one of them（Lv Hc L4） only had two exons and the exon2 was missed. Transcription analysis showed that these isoforms of Lv Hc L were up-regulated after WSSV challenge in WSSV-resistant shrimp, while the transcriptions were decreased constantly in WSSV-susceptible shrimp. It is suggested that the hemocyanin had rich polymorphism and was involved in the antiviral response. These results could extend our previous findings and provide insights into the immune feature of hemocyanin, which would be helpful for further studies aimed at antiviral mechanism in invertebrate.

Survivin isoforms and clinicopathological characteristics in colorectal adenocarcinomas using real-time qPCR

AIM:To investigate three isoforms of survivin in colorectal adenocarcinomas.METHODS:We used the LightCycler Technology(Roche),along with a common forward primer and reverse primers specific for the splice variants and two common hybridization probes labeled with fluorescein and LightCycler-Red fluorophore(LC-Red 640).Real time quantitative polymerase chain reaction(PCR) was performed on cDNAs from 52 tumor specimens from colorectal cancer patients and 10 unrelated normal colorectal tissues.In the patients group,carcinoembryonic antigen(CEA) and CA19-9 tumor markers were also measured immunochemically.RESULTS:Wild type survivin mRNA isoform was expressed in 48%of the 52 tumor samples,survivin-2b in 38%and survivin-ΔΕx3 in 29%,while no expression was found in normal tissues.The mRNA expression of wild type survivin presented a significant correlation with the expression of the ratio of survivin-2b,survivin-ΔΕx3,survivin-2b/wild type survivin and survivin-ΔΕx3/wild type survivin(P<0.001).The mRNA expression of wildsurvivin and survivin-ΔΕx3 was related with tumor size and invasion(P=0.006 and P<0.005,respectively).A significant difference was found between survivin-2b and morphologic cancer type.Also,the ratio of survivin-ΔEx3/ wild-survivin was significantly associated with prognosis.No association was observed between the three isoforms and grade,metastasis,Dukes stage and gender.The three isoforms were not correlated with CEA and CA19-9.CONCLUSION:Survivin isoforms may play a role in cell apoptosis and their quantification could provide information about clinical management of patients suffering from colorectal cancer.

Changes of Levels of Glutamine Synthetase Isoforms in Roots and Leaves in Responseto Nitrogen Fertilizer Application at Different Growth Stages in Irrigated Rice

Nitrogen is a key element to control the growth and yield of crops. Fertilizer urea nitrogen (N) 60,45, and 30 kg/hm2 was applied at three different stages, midtillering, panicle initiation, and flowering, of the growth and development of rice plants, respectively. At both midtillering and panicle initiation, the total activity of glutamine synthetase (GS) in rice roots and leaves was incrased remarkably as a result of a large amount of ammonia absorbed by roots. Native-PAGE and activity staining showed that the increase of total activity in rice roots and leaves was due to the synthesis of GSrb in roots and GS2 in leaves and that the activity of GSra in roots and GS1 in leaves remained constant. The results showed that the assimilation of external nitrogen was carried out by GSrb but not GSra in rice roots and that the activitry of GS2 was induced also by the external nitrogen, and that GSrb played main role in meeting the needs of the rapid tillering for nitrogen. At flowering, the activity of GS in rice roots and leaves did not change almost after topdressing. These rssults suggest that the change of GS activity in rice roots may use as a measure of the utilization efficiency of the fertilizer.

ApoE isoforms,treatment of diabetes and the risk of coronary heart disease

AIM:To analyze the risk of coronary heart disease in patients with type 2 diabetes mellitus(T2DM)receiving standard medical treatment.METHODS:We performed a retrospective chart analysis of 269 middle-aged patients(age 45-64 years,mean age,53.9±5.5 years)with T2DM and without atherosclerotic cardiovascular events who underwent typing to determine their apolipoprotein E(apoE)isoforms.The apoE isoforms were determined using isoelectric focusing,followed by immunoblotting.We retrospectively evaluated the charts of the 269 patients,recorded between their first visit to the hospital(the study's start point,between 1987 and 1992)and the occurrence of an atherosclerotic cardiovascular event(the study's endpoint)or January 2004,whichever came first.The age-adjusted mean values and the prevalences of covariates were calculated to compare the laboratory data among the apoE phenotypes.To investigate the association of risk factors with the incidence of coronary heart disease during the follow-up period,monovariate and multivariate Cox regression models were used.RESULTS:At enrollment,the mean serum low density lipoprotein(LDL)cholesterol levels were lowest(2.92± 0.89 mmol/L)among the subjects with apoE2(apoE2/2 or apoE2/3)and highest(3.52±0.77 mmol/L)among the subjects with apoE4(apoE3/4 or apoE4/4).No significant differences in mean age or the percentage of smokers were observed among the three groups.Furthermore,no significant differences were observed in the systolic and diastolic blood pressures,body mass index,HbA1c level or serum triglyceride levels among the three groups.There were 47 cases of coronary heart disease over 3285 person-years of follow-up.An age-adjusted multivariate Cox proportional model identified diabetic retinopathy(hazard ratio,2.38,95% CI:1.28-4.43,P=0.006),a high systolic blood pressure(hazard ratio,1.04,95%CI:1.02-1.06,P<0.001) and high HbA1c values(hazard ratio,1.19,95%CI:1.02-1.38,P=0.0029),but not the LDL cholesterol value at enrollment(hazard ratio,1.01,95%CI:0.97-1.05,P=0.77)nor the specific apoE isoform,as significant predictors of coronary heart disease.CONCLUSION:Under standard medical treatment of diabetes,including the control of LDL cholesterol levels,the apoE4 isoform was not associated with coronary heart disease among T2DM patients.

Aberrant expression of alternative isoforms of transcription factors in hepatocellular carcinoma

Hepatocellular carcinoma(HCC) is one of the most prevalent malignancies worldwide and the second leading cause of death among all cancer types. Deregulation of the networks of tissue-specific transcription factors(TFs) observed in HCC leads to profound changes in the hepatic transcriptional program that facilitates tumor progression. In addition, recent reports suggest that substantial aberrations in the production of TF isoforms occur in HCC. In vitro experiments have identified distinct isoform-specific regulatory functions and related biological effects of liver-specific TFs that are implicated in carcinogenesis, which may be relevant for tumor progression and clinical outcome. This study reviews available data on the expression of isoforms of liver-specific and ubiquitous TFs in the liver and HCC and their effects, including HNF4α, C/EBPs, p73 and TCF7 L2, and indicates that assessment of the ratio of isoforms and targeting specific TF variants may be beneficial for the prognosis and treatment of HCC.

Identification of the metabolite and cytochrome P450 isoforms involved in rat liver microsomal metabolism of TM208

To identify the metabolite and CYP450 isoforms involved in rat liver microsomal metabolism of TM208. The present study investigated the metabolism of TM208 and the effects of selective CYP450 inhibitors on the metabolism of TM208 in rat liver microsomes. Various specific inhibitors of CYP were used to identify the isoforms of CYP involved in the metabolism of TM208. The inhibitor of CYP2D and that of CYP2B had strong inhibitory effects on TM208 metabolism in a concentration-de- pendant manner, the inhibitor of CYP1A had a modest inhibitory effect, and the inhibitor of CYP3A seemed not to have an obvious inhibitory effect on TM208 metabolism. TM208 might mainly be metabolized by CYP2D and CYP2B in rat liver microsomes.

Multiple Isoforms of Olive Flounder (Paralichthys olivaceus) Pax3a and Pax3b Display Differential Regulations on Myogenic Differentiation

Paired box 3(Pax3)is a critical upstream regulator of the onset of myogenesis.We have previously identified two spliced isoforms of pax3a(pax3a-1 and pax3a-2)and three spliced isoforms of pax3b(pax3b-1,pax3b-2,and pax3b-3)in olive flounder,but their roles in myogenesis are unknown.In this study,we investigated their cellular localization,transcriptional activity on myod gene regulation,and roles in myogenesis.Different Pax3a and Pax3b isoforms revealed various subcellular localizations,which were related to their corresponding protein structures.Pax3a-1,Pax3a-2,and Pax3b-1 promoted the transcriptional activity of myod to dif-ferent degrees,whereas Pax3b-2 and Pax3b-3 had a slight inhibitory or no effect.The pairwise interaction analysis demonstrated the synergistic effect of Pax3b-1 and Pax3b-3 on myod transcriptional activity.The overexpression of different pax3a and pax3b isoforms differentially altered the spatial expression patterns of myod and differentially regulated the expression levels of their target genes(myod,myf5,and c-met)in zebrafish embryonic myogenesis.In addition,the different flounder myod promoter-driven pax3a/3b isoform expression vectors were successfully introduced into the skeletal muscles of juvenile flounder by electroporation.How-ever,none of them could change the mRNA expression levels of mstn,myf5,myod,myogenin,pax7a,and pax7b in the electroporated muscles.These results suggest that different Pax3a and Pax3b isoforms may precisely and collaboratively regulate embryonic myogenesis,but their roles in juvenile myogenesis are uncertain.

Effects of CXCL12 isoforms in a pancreatic pre-tumour cellular model:Microarray analysis

BACKGROUND Pancreatic ductal adenocarcinoma(PDAC)is the fourth leading cause of death among cancers,it is characterized by poor prognosis and strong chemoresistance.In the PDAC microenvironment,stromal cells release different extracellular components,including CXCL12.The CXCL12 is a chemokine promoting the communication between tumour and stromal cells.Six different splicing isoforms of CXCL12 are known(α,β,γ,δ,ε,θ)but their role in PDAC has not yet been characterized.AIM To investigate the specific role ofα,β,andγCXCL12 isoforms in PDAC onset.METHODS We used hTERT-HPNE E6/E7/KRasG12D(Human Pancreatic Nestin-Expressing)cell line as a pancreatic pre-tumour model and exposed it to theα,β,andγCXCL12 isoforms.The altered expression profiles were assessed by microarray analyses and confirmed by Real-Time polymerase chain reaction.The functional enrichment analyses have been performed by Enrichr tool to highlight Gene Ontology enriched terms.In addition,wound healing assays have been carried out to assess the phenotypic changes,in terms of migration ability,induced by theα,β,andγCXCL12 isoforms.RESULTS Microarray analysis of hTERT-HPNE cells treated with the three different CXCL12 isoforms highlighted that the expression of only a few genes was altered.Moreover,theαandβisoforms showed an alteration in expression of different genes,whereasγisoform affected the expression of genes also common withαandβisoforms.Theβisoform altered the expression of genes mainly involved in cell cycle regulation.In addition,all isoforms affected the expression of genes assay confirmed that CXCL12 enhanced the migration ability of hTERT-HPNE cells.Among the CXCL12 splicing isoforms,theγisoform showed higher induction of migration thanαandβisoforms.CONCLUSION Our data suggests an involvement and different roles of CXCL12 isoforms in PDAC onset.However,more investigations are needed to confirm these preliminary observations.

Insulin-like growth factor-1 mRNA isoforms and insulinlike growth factor-1 receptor mRNA expression in chronic hepatitis C

AIM: to evaluate the expression of different insulinlike growth factor(IGF)-1 mRNA isoforms and IGF-1 receptor(IGF-1R) mRNA in hepatitis C virus(HCV)-infected livers. METHODS: Thirty-four liver biopsy specimens from chronic hepatitis C(CH-C) patients were obtained before anti-viral therapy. Inflammatory activity(grading) and advancement of fibrosis(staging) were evaluated using a modified point scale of METAVIR. The samples were analyzed using quantitative real-time PCR technique. From fragments of liver biopsies and control liver that were divided and ground in liquid nitrogen, RNA was isolated using RNeasy Fibrous Tissue Mini Kit according to the manufacturer's instruction. Expression levels of IGF-1 mRNA isoforms(IGF-1A, IGF-1B, IGF-1C, P1, and P2) and IGF-1R mRNA were determined through normalization of copy numbers in samples as related to reference genes: glyceraldehyde-3-phosphate dehydrogenase and hydroxymethylbilane synthase. Results on liver expression of the IGF-1 mRNA isoforms and IGF-1R transcript were compared to histological alterations in liver biopsies and with selected clinical data in the patients. Statistical analysis was performed using Statistica PL v. 9 software. RESULTS: The study showed differences in quantitative expression of IGF-1 mRNA variants in HCV-infected livers, as compared to the control. Higher relative expression of total IGF-1 mRNA and of IGF-1 mRNAs isoforms(P1, A, and C) in HCV-infected livers as compared to the control were detected. Within both groups, expression of the IGF-1A mRNA isoform significantly prevailed over expressions of B and C isoforms. Expression of P1 mRNA was higher than that of P2 only in CH-C. Very high positive correlations were detected between reciprocal expressions of IGF-1 mRNA isoforms P1 and P2(r = 0.876). Expression of P1 and P2 mRNA correlated with IGF-1A mRNA(r = 0.891; r = 0.821, respectively), with IGF-1B mRNA(r = 0.854; r = 0.813, respectively), and with IGF-1C mRNA(r = 0.839; r = 0.741, respectively). Expression of IGF-1A mRNA significantly correlated with isoform B and C mRNA(r = 0.956; r = 0.869, respectively), and B with C isoforms(r = 0.868)(P < 0.05 in all cases). Lower expression of IGF-1A and B transcripts was noted in the more advanced liver grading(G2) as compared to G1. Multiple negative correlations were detected between expression of various IGF-1 transcripts and clinical data(e.g., alpha fetoprotein, HCV RNA, steatosis, grading, and staging). Expression of IGF-1R mRNA manifested positive correlation with grading and HCV-RNA. CONCLUSION: Differences in quantitative expression of IGF-1 mRNA isoforms in HCV-infected livers, as compared to the control, suggest that HCV may induce alteration of IGF-1 splicing profile.

Purification of enzymatically inactive peptidylarginine deiminase type 6 from mouse ovary that reveals hexameric structure different from other dimeric isoforms

The murine peptidylarginine deiminase (PAD) has five isoforms encoded by different genes and participates in a variety of cellular functions through the citrullination of target proteins. The crystal structure of human PAD4 with a dimeric form was previously solved because of the enzyme’s relevance to rheumatoid arthritis. PAD6, abundant in mouse oocytes and eggs, is believed to take part in early events of embryogenesis, but its biochemical properties are little understood. Here we have purified and characterized a recombinant PAD6. A PAD6 cDNA was cloned from mouse ovary RNA and expressed in Escherichia coli through pET29 and pGEX vectors. When benzoyl-L-arginine ethyl ester was used as a substrate, no appreciable activity was detected with a cell homogenate under conditions where a human PAD4 cDNA caused significant activity. Both proteins were affinity-purified to near homogeneity. The circular dichroism spectra of PAD6 and human PAD4 were similar in the far ultraviolet region. On molecular sieving, PAD6 was eluted faster than human PAD4. The cross-linking of PAD6 with dimethyl suberimidate clearly showed six bands on an sodium dodecyl sulfate-polyacrylamide gel. These results indicate that PAD6 can constitute a hexameric structure. The purified PAD6 still showed no enzymatic activity. This unique structure and loss in enzymatic activity is strongly suggested to favor the formation of egg cytoplasmic sheets as the architectural protein.

Akt isoforms differentially provide for chemoresistance in prostate cancer

Objective:Early prostate cancer micrometastatic foci undergo a mesenchymal to epithelial reverting transition,not only aiding seeding and colonization,but also rendering the tumor cells generally chemoresistant.We previously found that upregulated E-cadherin in the epithelial micrometastases activated canonical survival pathways,including PI3K-Akt,that protected the tumor cells from death;however,the extent of protection from blocking the pathway in its entirety was modest,because different isoforms may have alternately affected cell functioning.Here,we characterized Akt isoform expressions in primary and metastatic prostate cancers,as well as their individual contributions to chemoresistance.Methods:Akt isoforms and E-cadherin were manipulated with drugs,knocked down,and over expressed.Tumor cell killing was determined in vitro and in vivo.Overall survival was calculated from patient records and specimens.Results:Pan-Akt inhibition sensitized tumor cells to chemotherapy,and specific blockade of Akt1 or/and Akt2 caused cells to be more chemoresponsive.Overexpression of Akt3 induced apoptosis.A low dose of Akt1 or Akt2 inhibitor enabled standard chemotherapies to significantly eradicate metastatic prostate tumors in a mouse model,acting as chemosensitizers.In human specimens,we found Akt1 and Akt2 positively correlated,whereas Akt3 inversely correlated,with the overall survival of prostate cancer patients.Akt1high/Akt2high/Akt3low tumors had the worst outcomes.Conclusions:E-cadherin-induced activation of Akt1/2 isoforms was the essential mechanism of chemoresistance,whereas Akt3 made cells more fragile.These findings emphasized the need to target Akt1/2,rather than pan-Akt,as a rational therapeutic approach.

Bucolome N-Glucuronide Formation: Species Differences and Identification of Human UDP-Glucuronosyltransferase Isoforms

The barbituric acid derivative bucolome (BCP) is a nonsteroidal anti-inflammatory drug. The present study investigated whether BCP N-glucuronide (BCP-NG, the primary metabolite of BCP) was produced in mammalian species other than rats, and attempted to identify the UDP-glucuronosyltransferase (UGT) isoform (s) responsible for formation of BCP-NG in humans. BCP-NG was detected in all species tested. The results were as follows (pmol equivalent/ min/mg protein): rat, 479 ± 83;Mongolian gerbil, 378 ± 9;rabbit, 275 ±26;guinea pig, 257 ± 10;human, 242 ± 18;hamster, 177 ± 22;and mouse, 167 ± 15. Since human liver microsomes formed BCP-NG, we investigated the metabolites of BCP excreted in the urine of a patient after oral administration of BCP (600 mg). BCP and BCP-NG were excreted in the urine at amounts of 2.9 mg (about 0.5% of the dose) and 14.4 mg (about 2.5% of the dose) over 12 hours. In order to identify the UGT isoforms involved in formation of BCP-NG in humans, we investigated BCP-NG formation by the microsomes of insect cells expressing each of twelve UGT isoforms (hUGT1A1, 1A3, 1A4, 1A6, 1A7, 1A8, 1A9, 1A10, 2B4, 2B7, 2B15, and 2B17). As a result, BCP-NG formation (pmol equivalents/min/mg protein) was observed with microsomes expressing hUGT1A1 (142), 1A3 (196), 1A4 (8), 1A7 (8), 1A8 (66), 1A9 (38), 1A10 (9), 2B4 (7) and 2B7 (16). In particular, the activity of hUGT1A1 and 1A3 was high. These results suggest that the UGT isoforms responsible for formation of BCP-NG exist in various mammalian species, including humans, and that the UGT 1A family is primarily responsible for BCP N-glucuronide formation in humans.

Characteristics of myosin isoforms in mammalian skeletal muscle

The distribution of myosin heavy (MyHC) and myosin light chain (MyLC) isoform pattern in horse, rat and human skeletal muscle was investigated to establish relations between them and the role of myosin isoform patterns in mammalian muscle with different twitch characteristics was studied. These two isoforms were separated in a SDS-PAGE gel system, stained using the coomassie and silver staining procedures, and the results were analyzed using a G:BOX system. The relative content of MyHC I isoform in muscle was 2.6 times higher than in human compared to horse muscle (p < 0.001), and 6.3 times higher than in rat muscle (p < 0.001). The relative content of MyHC IIx/d isoform in horse muscle is 2.7 times, and in rat muscle 2.2 times higher in comparison with human muscle (p < 0.001). The role of the MyLC isoform distribution in mammalian skeletal muscle seems to depend on the oxidative capacity of muscles.

Estrogen and progesterone receptor isoforms expression in the stomach of Mongolian gerbils

AIM: We studied the estrogen receptor (ER) and progesterone receptor (PR) isoforms expression in gastric antrum and corpus of female gerbils and their regulation by estradiol (E2) and progesterone (P4). METHODS: Ovariectomized adult female gerbils were subcutaneously treated with E2, and E2 + P4. Uteri and stomachs were removed, the latter were cut along the greater curvature, and antrum and corpus were excised. Proteins were immunoblotted using antibodies that recognize ER-alpha, ER-beta, and PR-A and PR-B receptor isoforms. Tissues from rats treated in the same way were used as controls. RESULTS: Specific bands were detected for ER-alpha (68 KDa), and PR isoforms (85 and 120 KDa for PR-A and PR-B isoforms, respectively) in uteri, gastric antrum and corpus. We could not detect ER-beta isoform. PR isoforms were not regulated by E2 or P4 in uterus and gastric tissues of gerbils. ER-alpha isoform content was significantly down-regulated by E2 in the corpus, but not affected by hormones in uterus and gastric antrum. CONCLUSION: The presence of ER-alpha and PR isoforms in gerbils stomach suggests that E2 and P4 actions in this organ are in part mediated by their nuclear receptors.