Nitrogen-mediated volatilisation of defensive metabolites in tomato confers resistance to herbivores.

Plants synthesise a vast array of volatile organic compounds (VOCs), which serve as chemical defence and communication agents in their interactions with insect herbivores. Although nitrogen (N) is a critical resource in the production of plant metabolites, its regulatory effects on defensive VOCs remain largely unknown. Here, we investigated the effect of N content in tomato (Solanum lycopersicum) on the tobacco cutworm (Spodoptera litura), a notorious agricultural pest, using biochemical and molecular experiments in combination with insect behavioural and performance analyses. We observed that on tomato leaves with different N contents, S. litura showed distinct feeding preference and growth and developmental performance. Particularly, metabolomics profiling revealed that limited N availability conferred resistance upon tomato plants to S. litura is likely associated with the biosynthesis and emission of the volatile metabolite α-humulene as a repellent. Moreover, exogenous application of α-humulene on tomato leaves elicited a significant repellent response against herbivores. Thus, our findings unravel the key factors involved in N-mediated plant defence against insect herbivores and pave the way for innovation of N management to improve the plant defence responses to facilitate pest control strategies within agroecosystems.

Ada2 and Ada3 Regulate Hyphal Growth, Asexual Development, and Pathogenicity in Beauveria bassiana by Maintaining Gcn5 Acetyltransferase Activity.

The histone acetyltransferase (HAT) Gcn5 ortholog is essential for a variety of fungi. Here, we characterize the roles of Ada2 and Ada3, which are functionally linked to Gcn5, in the insect-pathogenic fungus Beauveria bassiana. Loss of Ada2 and Ada3 led to severe hyphal growth defects on rich and minimal media and drastic decreases in blastospore yield and conidiation capacity, with abnormal conidia-producing structures. ΔAda2 and ΔAda3 exhibited a delay in conidial germination and increased sensitivity to multiple chemical stresses and heat shock. Nearly all their pathogenicity was lost, and their ability to secrete extracellular enzymes, Pr1 proteases and chitinases for cuticle degradation was reduced. A yeast two-hybrid assay demonstrated that Ada2 binds to Ada3 and directly interacts with Gcn5, confirming the existence of a yeast-like Ada3-Ada2-Gcn5 HAT complex in this fungus. Additionally, deletion of the Ada genes reduced the activity of Gcn5, especially in the ΔAda2 strain, which was consistent with the acetylation level of histone H3 determined by Western blotting. These results illustrate the dependence of Gcn5 enzyme activity on Ada2 and Ada3 in fungal hyphal growth, asexual development, multiple stress responses, and pathogenicity in B. bassiana. IMPORTANCE The histone acetyltransferase Gcn5 ortholog contributes significantly to the growth and development of various fungi. In this study, we found that Ada2 and Ada3 have critical regulatory effects on Gcn5 enzyme activity and influence the acetylation of histone H3. Deletion of Ada2 or Ada3 decreased the fungal growth rate and asexual conidial yield and increased susceptibility to multiple stresses in Beauveria bassiana. Importantly, Ada genes are vital virulence factors, and their deletion caused the most virulence loss, mainly by inhibiting the activity of a series of hydrolytic enzymes and the dimorphic transition ability. These findings provide a new perspective on the function of the Gcn5 acetyltransferase complex in pathogens.

Low-frequency electroacupuncture improves disordered hepatic energy metabolism in insulin-resistant Zucker diabetic fatty rats via the AMPK/mTORC1/p70S6K signaling pathway.

BACKGROUND AND AIM: Disordered hepatic energy metabolism is found in obese rats with insulin resistance (IR). There are insufficient experimental studies of electroacupuncture (EA) for IR and type 2 diabetes mellitus (T2DM). The aim of this study was to probe the effect of EA on disordered hepatic energy metabolism and the adenosine monophosphate (AMP)-activated protein kinase (AMPK)/mammalian target of rapamycin complex 1 (mTORC1)/ribosomal protein S6 kinase, 70-kDa (p70S6K) signaling pathway. METHODS: Zucker Diabetic Fatty (ZDF) rats were randomly divided into three groups: EA group receiving EA treatment; Pi group receiving pioglitazone gavage; and ZF group remaining untreated (n = 8 per group). Inbred non-insulin-resistant Zucker lean rats formed an (untreated) healthy control group (ZL, n = 8). Fasting plasma glucose (FPG), fasting insulin (FINS), C-peptide, C-reactive protein (CRP) and homeostatic model assessment of insulin resistance (HOMA-IR) indices were measured. Hematoxylin-eosin (H&E) staining was used to investigate the liver morphologically. The mitochondrial structure of hepatocytes was observed by transmission electron microscopy (TEM). Western blotting was adopted to determine protein expression of insulin receptor substrate 1 (IRS-1), mTOR, mTORC1, AMPK, tuberous sclerosis 2 (TSC2) and p70S6K, and their phosphorylation. RT-PCR was used to quantify IRS-1, mTOR, mTORC1, AMPK and p70S6K mRNA levels. RESULTS: Compared with the ZF group, FPG, FINS, C-peptide, CRP and HOMA-IR levels were significantly reduced in the EA group (p < 0.05, p < 0.01). Evaluation of histopathology showed improvement in liver appearances following EA. Phosphorylation levels of AMPK, mTOR and TSC2 decreased, and IRS-1 and p70S6K increased, in hepatocytes of the ZF group, while these negative effects appeared to be alleviated by EA. CONCLUSIONS: EA can effectively ameliorate IR and regulate energy metabolism in the ZDF rat model. AMPK/mTORC1/p70S6K and related molecules may represent a potential mechanism of action underlying these effects.

[Clinical therapeutic effect of hyperlipidemia of turbid phlegm obstruction pattern/syndrome treated with the different Jin's three-needle therapies].

OBJECTIVE: To compare the differences in clinical effects on hyperlipidemia of turbid phlegm obstruction pattern/syndrome treated with the different Jin's three-needle therapies so as to provide a new approach and theoretic evidence for the clinical optimal scheme of acupuncture on hyperlipidemia. METHODS: A total of 90 patients were randomly divided into education group, electroacupuncture group and catgut embedding group (30 cases in each). The routine health education was given to the education group. On the base of the treatment as the education group, electroacupuncture was applied to the electroacupuncture group for 30 min each time, twice a week; and the catgut embedding was applied to the catgut embedding group at the same acupoints as the electroacupuncture group, once a week. The treatment was given consecutively for 8 weeks in each group. Before and after treatment, the obesity indices [weight, waistline, body mass index (BMI)], blood lipid indices[serum total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C)] and insulin resistance indices [fasting blood glucose(FBG), fasting plasma insulin(FINS), homeostasis model assessment-estimated insulin resistance (HOMA-IR)] were observed in the three groups before and after treatment. RESULTS: After treatment, in the electroacupuncture group and the catgut embedding group, the results of the obesity indices, e.g. weight, waistline and BMI, the levels of blood lipid, e.g.TC, TG, LDL-C and the insulin resistance indices, e.g. FINS and HOMA-IR were all obviously decreased compared with those before treatment (P<0.05, P<0.01), and the level of HDL-C apparently increased than that before treatment (P<0.01). In the catgut embedding group, FBG was obviously decreased after treatment as compared with that before treatment (P<0.01). After treatment, the improvements in LDL-C and HDL-C in the catgut embedding group were superior to those in the electroacupuncture group (P<0.05). Regarding the obesity indices and insulin resistance indices, the differences were not statistically significant in comparison between the catgut embedding group and the electroacupuncture group (all P>0.05). The total effective rate was 90.0% in the catgut embedding group (27/30) and it was 83.3% (25/30) in the electroacupuncture group, either of them was better than 60.0% (18/30) in the education group , indicating the statistical significance (P<0.01, P<0.05). CONCLUSION: On the base of health education, either the catgut embedding therapy or electroacupuncture of Jin's three-needle treatment achieves the positive regulation on the abnormal lipid metabolism and insulin resistance. The hypoglycemic effect and the impro-ving effect in LDL-C and HDL-C of the catgut embedding therapy are superior to electroacupuncture.

Chitin deacetylase 1 and 2 are indispensable for larval-pupal and pupal-adult molts in Heortia vitessoides (Lepidoptera: Crambidae).

Heortia vitessoides Moore is a notorious defoliator of Aquilaria sinensis (Lour.) Gilg trees. Chitin deacetylases (CDAs) catalyze the N-deacetylation of chitin, which is a crucial process for chitin modification. Here, we identified and characterized HvCDA1 and HvCDA2 from H. vitessoides. HvCDA1 and HvCDA2 possess typical domain structures of CDAs and belong to the Group I CDAs. HvCDA1 and HvCDA2 were highly expressed before and after the larval-larval molt. In addition, both exhibited relatively high mRNA expression levels during the larval-pupal molt, the pupal stage, and the pupal-adult molt. HvCDA1 and HvCDA2 transcript expression levels were highest in the body wall and relatively high in the larval head. Significant increases in the HvCDA1 and HvCDA2 transcript expression levels were observed in the larvae upon exposure to 20-hydroxyecdysone. RNA interference-mediated HvCDA1 and HvCDA2 silencing significantly inhibited HvCDA1 and HvCDA2 expression, with abnormal or nonviable phenotypes being observed. Post injection survival rates of the larvae injected with dsHvCDA1 and dsHvCDA2 were 66.7% and 46.7% (larval-pupal) during development and 23.0% and 6.7% (pupal-adult), respectively. These rates were significantly lower than those of the control group insects. Our results suggest that HvCDA1 and HvCDA2 play important roles in the larval-pupal and pupal-adult transitions and represent potential targets for the management of H. vitessoides.

Neurexophilin and PC-esterase domain family member 4 (NXPE4) and prostate androgen-regulated mucin-like protein 1 (PARM1) as prognostic biomarkers for colorectal cancer.

Owing to the high morbidity and mortality, novel biomarkers in the occurrence and development of colorectal cancer (CRC) are needed nowadays. In this study, the CRC-related datasets were downloaded from the Gene Expression Omnibus (GEO) database and The Cancer Genome Atlas (TCGA) database. After screening the differentially expressed genes (DEGs) in R software, a total of 238 upregulated and 199 downregulated DEGs were revealed simultaneously. Then the Kaplan-Meier survival analysis and Cox regression analysis were used to reveal the prognostic function of these DEGs. Neurexophilin and PC-esterase domain family member 4 (NXPE4) and prostate androgen-regulated mucin-like protein 1 (PARM1) were two outstanding independent overall survival (OS) and relapse-free survival (RFS) prognostic genes of CRC in TCGA database. We next verified the expression of NXPE4 and PARM1 messenger RNA (mRNA) levels were significantly lower in CRC tumor tissue than in the adjacent noncancerous tissue in our clinical samples, and NXPE4 mRNA expression level was related to the tumor location and tumor size, while PARM1 was related to tumor location, lymph nodes metastasis, and tumor size. This study demonstrated that NXPE4 and PARM1 might be two potential novel prognostic biomarkers for CRC.

[Progress of researches on mechanisms of acupuncture therapy for insulin resistance].

Insulin resistance (IR) is a common pathophysiological basis of many chronic diseases, such as obesity, type 2 diabetes mellitus (T2DM), nonalcoholic fatty liver disease, cerebral vascular disease, cardiovascular and neurodegenerative diseases, etc. Acupuncture therapy has been demonstrated to have a positive role in reducing IR level in clinical practice. In the present paper, we summarized development of researches on the mechanism of acupuncture therapy underlying improvement of IR in recent 10 years from 1) regulating expression of hypothalamic phosphatidylinositol-3-kinase (PI3K)-p85 and PI3K-P110 proteins in obesity rats; 2) regulating the levels of some related proteins of insulin target tissues (liver and skeletal muscle), such as insulin receptor substrate-1 (IRS)-1 and -2, glucose transporter mRNAs and proteins, sterol regulatory element-binding protein 1 (SREBP-1) and fatty acid synthetase proteins; 3) suppressing inflammatory reaction of liver tissue and down-regulating serum adiponectin in T2DM rats; 4) raising the activity of superoxide dismutase (SOD) and reducing the levels of reactive oxygen species, and malondialdehyde (MDA) contents of quadriceps femoris in spontaneous IR rats; and 5) attenuating structural injury of pancreas islet and apoptosis of pancreatic ß cells in diabetes rats. Multi-levels and various systems of the neuro-endocrine-immune networks are involved in the actions of acupuncture in the improvement of IR. In the future, more attention should be paid to the study on the acupoint specificity, suitable acupoint combinations and stimulus parameters in clinical treatment of IR related various metabolic diseases, further optimizing clinical treatment protocols.

[Eletroacupuncture improves lipid metabolic disorder by regulating hepatic AMPK/p38 MAPK/RRARγ signaling in rats with high-fat diet-induced insulin resistance].

OBJECTIVE: To observe the effect of eletroacupuncture (EA) intervention on lipid metabolism and expression of AMP-activated kinase (AMPK), p38 mitogen-activated protein kinase (p38 MAPK) and peroxisome proliferator-activated receptor γ (PPARγ) protein in the liver in rats with insulin resistance (IR), so as to reveal its mechanisms underlying improvement of IR. METHODS: Forty male SD rats were randomly divided into blank control, model, medication, and EA groups (n＝8 in each). The IR model was established by feeding the rats with high-fat diet for 12 weeks. After successful establishment of model, the rats in the blank control group and model group were fixed in the self-made rat bag without receiving any treatment. The rats in the medication group were treated by gavage of pioglitazone (10 mL/kg). EA (2 Hz /100 Hz, 1 mA) was applied to bilateral "Fenglong"(ST40) and "Sanyinjiao"(SP6) for 20 min, once a day, for continuous 14 days for rats in the EA group. The ultrastructure of the liver tissue was observed by transmission electron microscope (TEM). Blood samples were taken from the abdominal aorta for detecting serum C-peptide (C-P), adiponectin (ADP), leptin (LEP) and resistin (RES) contents using enzyme linked immunosorbent assay (ELISA). The expression levels of AMPK, p38 MAPK and PPARγ proteins in the liver tissue were detected by Western blot. RESULTS: After modeling, the contents of serum C-P, LEP and RES, and the expression of liver p38 MAPK protein were significantly up-regulated (P<0.01, P<0.05), and the content of ADP and expression of AMPK and PPARγ significantly down-regulated in the model group compared with the blank control group (P<0.01). The increased contents of C-P, LEP and RES, and p38 MAPK protein expression and the decreased serum ADP and hepatic AMPK and PPARγ expression levels were completely reversed in both the EA and medication groups relevant to the model group (P<0.01, P<0.05). No significant differences were found between the EA and medication groups in up-regulating the levels of ADP, AMPK and PPARγ and in down-regulating the levels of C-P, LEP, RES and p38 MAPK(P>0.05). Outcomes of TEM showed that morphological structure of liver mitochondria was damaged, including a large number of lipid droplets, being blur in appearance, rupture of partial membrane, dissapearance of partial mitochondrial crests with vacuolus-like appearance and decrease of rough endoplasmic reticulum in the model group, which was relatively milder in both EA and medication groups. CONCLUSION: EA intervention is able to improve the disorder of lipid metabolism of IR rats, which may be associated with its effects in lowering the activity of fatty acid synthesis-related enzymes and regulating AMPK/p38 MAPK/PPARγ signaling to improve IR in the liver tissue.

MALAT1: a potential biomarker in cancer.

PURPOSE: The research of long non-coding RNAs (lncRNAs) has become a new passion with the discovery of abundant new lncRNAs and extensive investigation of their roles in various diseases, especially in cancers. Metastasis associated in lung adenocarcinoma transcript 1 (MALAT1) emerges as a hotspot, which has been reported to be involved in dysregulation of cell signaling and closely correlated with cancer development, progression, and response to therapy. This review is a brief update of the current knowledge related to the role of MALAT1 in cancer-associated molecular pathways and pathophysiology and possible determinants for MALAT1 to function as a biomarker, aiming to stimulate the basic investigation of lncRNA MALAT1 as well as its translation to clinical applications. METHODS: We have selected vast literature from electronic databases including studies associated with its clinical significance and the pivotal functions in cancer processes such as cell proliferation, apoptosis, metastasis, immunity, angiogenesis, and drug resistance. RESULTS: Studies have shown that aberrant expression of MALAT1 is related to cancer pathophysiology with the potential to be translated clinically and MALAT1 can regulate cancer processes by interacting with molecules, such as proteins, RNAs and DNAs, and further altering different signal pathways. CONCLUSION: MALAT1 lncRNA promises to be a potential biomarker for cancer diagnosis as well as prognosis. Additionally, it might be a therapeutic target for human cancers.

Emerging role of long non-coding RNAs in cisplatin resistance.

Cisplatin (CDDP) is one of the most commonly used chemotherapy drugs for the treatment of various cancers. Although platinum-based therapies are highly efficacious against rapidly proliferating malignant tumors, the development of CDDP resistance results in significant relapse as well as decreased overall survival rates, which is a significant obstacle in CDDP-based cancer therapy. Long non-coding RNAs (lncRNAs) are involved in cancer development and progression by the regulation of processes related to chromatin remodeling, transcription, and posttranscriptional processing. Emerging evidence has recently highlighted the roles of lncRNAs in the development of CDDP resistance. In this review, we discuss the roles and mechanisms of lncRNAs in CDDP chemoresistance, including changes in cellular uptake or efflux of a drug, intracellular detoxification, DNA repair, apoptosis, autophagy, cell stemness, and the related signaling pathways, aiming to provide potential lncRNA-targeted strategies for overcoming drug resistance in cancer therapy.

[Effect of Eletroacupuncture Intervention on Insulin Resistance, Lipid Metabolic Disorder and Expression of Hepatic SREBP-1 c and Fatty Acid Synthase Proteins in Rats with Hyperlipidemia].

OBJECTIVE: To observe the effect of electroacupuncture(EA) of "Fenglong" (ST 40) and "Sanyinjiao" (SP 6) on lipid metabolic disorder, insulin resistance (IR) and expression of sterol regulatory element blinding protein-1 (SREBP-1) c and fatty acid synthase (FAS) proteins in the liver tissue in hyperlipidemia rats with IR, so as to reveal its mechanisms underlying improvement of IR. METHODS: Forty male SD rats were randomly divided into blank control, model, medication and EA groups (n＝8 in each group). The IR model was established by feeding the rat with high-fat diet. Rats of the medication group were treated by intragastric administration of pioglitazone (10 mL/kg). For rats of the EA group, EA (2 Hz/100 Hz，1 mA) was applied to bilateral ST 40 and SP 6, once daily for 14 days. The insulin sensitivity index (ISI) was assessed by calculating 60－120 min glucose infusion rate (GIR 60－120) with euglycemic hyperinsulinemic clamp in reference to Kraegen's and colleagues' methods. Fasting blood samples (10 mL) were collected and analyzed for fasting blood glucose (FBG) using enzyme method, serum fasting insulin(FINS) using ELISA, free fatty acid(FFA) using spectrophotometry, and total triglyceride(TG) and total cholesterol(TC) employing glycerine phosphate oxidase peroxidase (GPO-PAP) assay, low density lipoprotein(LDL), high density lipoprotein(HDL) levels using combined filiter paper activity and lipase activity methods, respectively. The IR level was assessed by calculating homeostatic model assessment of insulin resistance (HOMA-IR) using the formula (FBG×FINS)/22.5. The expression levels of SREBP-1 c and FAS proteins in the liver tissue were detected by Western blot. RESULTS: Following modeling, the GIR 60－120 and serum HDL were significantly decreased(P<0.01), and the HOMA-IR, serum FBG, FINS, FFA, TG, TC and LDL, and the expression levels of hepatic SREBP-1 c and FAS proteins were significantly increased in comparison with the blank control group(P<0.01). After the intervention, the decreased GIR 60－120 and serum HDL levels were considerably up-regulated (P<0.01), and the increased FBG, FINS, FFA, TG, TC and LDL, and hepatic SREBP-1 c and FAS protein levels were notably down-regulated in both EA and medication groups relevant to the model group (P<0.05, P<0.01). No significant differences were found between the EA and medication groups in all the indexes mentioned above (P>0.05). CONCLUSION: EA intervention is able to improve the disorder of lipid metabolism of IR rats, which may be associated with its effects in reducing the expression of SREBP-1 c and FAS proteins and in lowering the synthesis of fatty acid.

LncRNA H19 is a major mediator of doxorubicin chemoresistance in breast cancer cells through a cullin4A-MDR1 pathway.

Development of chemoresistance is a persistent problem during cancer treatment. Long non-coding RNAs (LncRNAs) are currently emerging as an integral functional component of the human genome and as critical regulators of cancer development and progression. In the present study, we investigated the role and molecular mechanism of H19 lncRNA in chemoresistance development by using doxorubicin (Dox) resistance in breast cancer cells as a model system. H19 lncRNA expression was significantly increased in anthracycline-treated and Dox-resistant MCF-7 breast cancer cells. This H19 overexpression was contributed to cancer cell resistance to anthracyclines and paclitaxel as knockdown of H19 lncRNA by a specific H19 shRNA in Dox-resistant cells significantly improved the cell sensitivity to anthracyclines and paclitaxel. Furthermore, gene expression profiling analysis revealed that a total of 192 genes were associated with H19-mediated Dox resistance. These genes were enriched in multiple KEGG pathways that are related to chemoresistance. Using genetic and pharmacological approaches, we demonstrated that MDR1 and MRP4 were major effectors of H19-regulated Dox resistance in breast cancer cells as MDR1 and MRP4 expression was markedly elevated in Dox-resistant cells while dramatically reduced when H19 was knocked down. Moreover, we found that CUL4A, an ubiquitin ligase component, was a critical factor bridging H19 lncRNA to MDR1 expression, and a high tumor CUL4A expression was associated with low survival in breast cancer patients treated with chemotherapy. These data suggest that H19 lncRNA plays a leading role in breast cancer chemoresistance, mediated mainly through a H19-CUL4A-ABCB1/MDR1 pathway.

[Acupoints Selection Exploring for Acupuncture Treatment of Insulin Resistance Based on Data Mining].

OBJECTIVE: To analyze the characteristics and rules of acupoint selection for acupuncture treatment of insulin resistance. METHODS: Data collections were conducted by searching references on acupuncture treatment of insulin resistance in PubMed, CNKI, VIP data base from 1991 to 2016, and acupuncture prescription data base for acupuncture treatment of insulin resistance was established. Data mining was applied to analyze the characteristics and rules of acupoint selection. RESULTS: A total of 64 papers were recruited, and 73 acupoints were selected in these papers. It was found that the acupoints as Zusanli (ST 36), Sanyinjiao (SP 6), Fenglong (ST 40) and Taichong (LR 3) were used with highest frequencies. All acupoints selected distributed in 13 meridians, especially Foot Yangming Stomach Meridian, Foot Taiyin Bladder Meridian, and Conception Vessel with a total frequency of 58.07%. The special acupoints including five-shu points, eight confluent points and back-shu points, accounted for 56.71%. CONCLUSIONS: This study excavated the regular acupoint selection and acupoints compatibility for acupuncture treatment in patients with insulin resistance, giving evidence based confirming and direction for acupuncture clinical treatment.

Alteration of nuclear matrix-intermediate filament system and differential expression of nuclear matrix proteins during human hepatocarcinoma cell differentiation.

AIM: To investigate the association between the configurational and compositional changes of nuclear matrix and the differentiation of carcinoma cells. METHODS: Cells cultured with or without 5 x 10(-3) mmol/L of hexamethylene bisacetamide (HMBA) on Nickel grids were treated by selective extraction and prepared for whole mount observation under electron microscopy. The samples were examined under transmission electron microscope. Nuclear matrix proteins were selectively extracted and subjected to subcellular proteomics study. The protein expression patterns were analyzed by PDQuest software. Spots of differentially expressed nuclear matrix proteins were excised and subjected to in situ digestion with trypsin. The peptides were analyzed by matrix-assisted laser-desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS). Data were submitted for database searching using Mascot tool (www.matrixscience.com). RESULTS: The nuclear matrix (NM) and intermediate filament (IF) in SMMC-7721 hepatocarcinoma cells were found relatively sparse and arranged irregularly. The nuclear lamina was non-uniform, and two kinds of filaments were not tightly connected. After induction for differentiation by HMBA, the NM-IF filaments were concentrated and distributed uniformly. The heterogeneous population of filaments, including highly branched ultrathin filaments could also be seen in the regular meshwork. The connection between the two kinds of filaments and the relatively thin, condensed and sharply demarcated lamina composed of intermediate-sized filaments was relatively fastened. Meanwhile, 21 NM proteins changed remarkably during SMMC-7721 cell differentiation. Four proteins, i.e. mutant Pyst1, hypothetical protein, nucleophosmin 1, and LBP were downregulated, whereas four other proteins, eIF6, p44 subunit, beta-tubulin, and SIN3B were upregulated with the last one, SR2/ASF found only in the differentiated SMMC-7721 cells. CONCLUSION: The induced differentiation of SMMC-7721 cells by HMBA is accompanied by the configurational changes of nuclear matrix-intermediate filament (NM-IF) system and the compositional changes of nuclear matrix protein expression. These changes may be important morphological or functional indications of the cancer cell reversion.

[Changes of nuclear matrix proteins during differentiation of human osteosarcoma MG-63 cells induced by HMBA].

Human osteosarcoma MG-63 cells were induced into differentiation by hexamethylene bisacetamide (HMBA). Its nuclear matrix proteins were selectively extracted, and subjected to two dimensional gel electrophoresis analysis. The resulted protein patterns were analyzed by Melanie software. There were 12 spots changed remarkably during the differentiation induced by HMBA, nine of which were identified. The up-regulated proteins were identified as MHC class II antigen, interferon-stimulated gene factor 3d, hypothetical protein DKFZp434M2221.1,8-hydroxy-guanine glycosylase homolog ogg1, and vimentin. The down-regulated ones were hnRNP A2/B1 and actin; and two newly expressed proteins under induction were 60S ribosomal protein L21 and ST2 protein. This study suggests that the induced differentiation of carcinoma cells is accompanied with changes of nuclear matrix proteins, and confirms the presence of some specific nuclear matrix proteins associated with carcinoma cell growth and differentiation. The changed nuclear matrix proteins are potential markers for cancer diagnosis or targets for cancer therapy.

Changes of nuclear matrix proteins following the differentiation of human osteosarcoma MG-63 cells.

Human osteosarcoma MG-63 cells were induced into differentiation by 5 mmol/L hexamethylene bisacetamide (HMBA). Their nuclear matrix proteins (NMPs) were selectively extracted and subjected to two-dimensional gel electrophoresis analysis. The results of protein patterns were analyzed by Melanie software. The spots of differentially expressed NMPs were excised and subjected to in situ digestion with trypsin. The maps of peptide mass fingerprinting were obtained by MALDI-TOF-MS analysis, and were submitted for NCBI database searches by Mascot tool. There were twelve spots changed remarkably during the differentiation induced by HMBA, nine of which were identified. The roles of the regulated proteins during the MG-63 differentiation were analyzed. This study suggests that the induced differentiation of cancer cells is accompanied by the changes of NMPs, and confirms the presence of some specific NMPs related to the cancer cell proliferation and differentiation. The changed NMPs are potential markers for cancer diagnosis or targets for cancer therapy.