scholarly journals Neudesin Neurotrophic Factor Promotes Bovine Preadipocyte Differentiation and Inhibits Myoblast Myogenesis

Animals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1109 ◽  
Author(s):  
Xiaotong Su ◽  
Yaning Wang ◽  
Anqi Li ◽  
Linsen Zan ◽  
Hongbao Wang
Keyword(s):  
Adipose Tissue ◽  
Protein Expression ◽  
Mrna Expression ◽  
Neurotrophic Factor ◽  
Muscle Development ◽  
Expression Patterns ◽  
Marker Genes ◽  
Qinchuan Cattle ◽  
Preadipocyte Differentiation ◽  
Expression Levels

Neudesin neurotrophic factor (NENF) is a secreted protein that is essential in multiple biological processes, including neural functions, adipogenesis, and tumorigenesis. In our previous study, NENF was significantly inhibited in the bovine adipocytes-myoblasts co-culture system. However, studies on NENF regulation of bovine muscle development and involvement in the cross-talk between adipose tissue and skeletal muscle have not been reported. Hence, the aim of this study was to clarify the functional roles of NENF in bovine preadipocytes and myoblasts. Real-time quantitative PCR (RT-qPCR) was performed to examine the spatial expression patterns of NENF in different tissues, and the results showed that NENF was highly expressed in the muscle of four-day-old and 24-month-old Qinchuan cattle. Compared with four-day-old Qinchuan cattle, the expression level of NENF was significantly up-regulated in 24-month-old bovine adipose tissue. To explore the roles of NENF in bovine myoblast and preadipocyte differentiation, small interfering RNA (siRNA) targeting the NENF gene were transfected into bovine preadipocytes and myoblasts to knock down the expression of the NENF gene. The results showed that the knockdown of NENF in differentiating adipocytes attenuated lipid accumulation, decreased the mRNA expression of adipogenic key marker genes PPARγ, CEBPα, CEBPβ, FASN, and SCD1, and decreased the protein expression of PPARγ, CEBPα, and FASN. The formation of myotubes was significantly accelerated, and the mRNA expression levels of myogenic marker genes MYOD1, MYF5, MYF6, MEF2A, MEF2C, and CKM, and the protein expression levels of MYOD1, MYF6, MEF2A, and CKM were up-regulated in myoblasts where NENF was knocked down. In short, the knockdown of NENF inhibited preadipocyte differentiation and promoted myoblast myogenesis.

scholarly journals KIT is involved in melanocyte proliferation, apoptosis and melanogenesis in the Rex Rabbit

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9402
Author(s):  
Shuaishuai Hu ◽  
Yang Chen ◽  
Bohao Zhao ◽  
Naisu Yang ◽  
Shi Chen ◽  
...  
Keyword(s):  
Protein Expression ◽  
Mrna Expression ◽  
Expression Patterns ◽  
Melanin Content ◽  
Expression Levels ◽  
Qrt Pcr ◽  
Proliferation And Apoptosis ◽  
Mrna And Protein Expression ◽  
Different Color ◽  
Rex Rabbit

Background Melanocytes play an extremely important role in the process of skin and coat colors in mammals which is regulated by melanin-related genes. Previous studies have demonstrated that KIT is implicated in the process of determining the color of the coat in Rex rabbits. However, the effect of KIT on the proliferation and apoptosis of melanocytes and melanogenesis has not been clarified. Methods The mRNA and protein expression levels of KIT were quantified in different coat colored rabbits by qRT-PCR and a Wes assay. To identify whether KIT functions by regulating of melanogenesis, KIT overexpression and knockdown was conducted in melanocytes, and KIT mRNA expression and melanin-related genes TYR, MITF, PMEL and DCT were quantified by qRT-PCR. To further confirm whether KIT influences melanogenesis in melanocytes, melanin content was quantified using NaOH lysis after overexpression and knockdown of KIT. Melanocyte proliferation was estimated using a CCK-8 assay at 0, 24, 48 and 72 h after transfection, and the rate of apoptosis of melanocytes was measured by fluorescence-activated cell sorting. Results KITmRNA and protein expression levels were significantly different in the skin of Rex rabbits with different color coats (P < 0.05), the greatest levels observed in those with black skin. The mRNA expression levels of KIT significantly affected the mRNA expression of the pigmentation-related genes TYR, MITF, PMEL and DCT (P < 0.01). Melanin content was evidently regulated by the change in expression patterns of KIT (P < 0.01). In addition, KIT clearly promoted melanocyte proliferation, but inhibited apoptosis. Conclusions Our results reveal that KIT is a critical gene in the regulation of melanogenesis, controlling proliferation and apoptosis in melanocytes, providing additional evidence for the mechanism of pigmentation of animal fur.

scholarly journals The role of CXCR3 and its ligands expression in Brucellar spondylitis

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Xin Hu ◽  
Xiaoqian Shang ◽  
Liang Wang ◽  
Jiahui Fan ◽  
Yue Wang ◽  
...  
Keyword(s):  
Protein Expression ◽  
Mrna Expression ◽  
Mononuclear Cells ◽  
Healthy Controls ◽  
Inflammatory Infiltration ◽  
Peripheral Blood Mononuclear ◽  
Expression Levels ◽  
Inflammatory Damage ◽  
Ifn Γ ◽  
Mrna Expression Levels

Abstract Aim Brucellar spondylitis (BS) is one of the most serious complications of brucellosis. CXCR3 is closely related to the severity of disease infection. This research aimed to study the degree of BS inflammatory damage through analyzing the expression levels of CXCR3 and its ligands (CXCL9 and CXCL10) in patients with BS. Methods A total of 29 BS patients and 15 healthy controls were enrolled. Real-Time PCR was used to detect the mRNA expression levels of IFN-γ, CXCR3, CXCL9 and CXCL10 in peripheral blood mononuclear cells (PBMCs) of BS patients and healthy controls. Hematoxylin-Eosin staining was used to show the pathological changes in BS lesion tissues. Immunohistochemistry staining was used to show the protein expression levels of Brucella-Ab, IFN-γ, CXCR3, CXCL9 and CXCL10 in BS lesion tissues. At the same time, ELISA was used to detect the serum levels of IFN-γ, CXCL9 CXCL10 and autoantibodies against CXCR3 in patients with BS. Results In lesion tissue of BS patients, it showed necrosis of cartilage, acute or chronic inflammatory infiltration. Brucella-Ab protein was abundantly expressed in close lesion tissue. And the protein expression levels of IFN-γ, CXCR3 and CXCL10 were highly expressed in close lesion tissue and serum of BS patients. At the same time, the mRNA expression levels of IFN-γ, CXCR3 and CXCL10 in PBMCs of BS patients were significantly higher than those in controls. Conclusion In our research, the expression levels of IFN-γ, CXCR3 and its ligands were significantly higher than those in controls. It suggested that high expression levels of IFN-γ, CXCR3 and its ligands indicated a serious inflammatory damage in patients with BS.

Abstract 339: Impaired Periaortic Adipocyte Differentiation in Angiotensin AT1 Receptor-Deficient Mice: Possible Role in Proinflammatory Phenotypic Modulation of Perivascular Adipose Tissue

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Daisuke Irie ◽  
Hiroyuki Yamada ◽  
Taku Kato ◽  
Hiroyuki Kawahito ◽  
Kouji Ikeda ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Adipocyte Differentiation ◽  
At1 Receptor ◽  
Brown Adipocyte ◽  
Marker Genes ◽  
Interscapular Brown Adipose Tissue ◽  
Perivascular Adipose Tissue ◽  
Expression Levels ◽  
Brown Adipose ◽  
Differentiation Marker

[BACKGROUND] The angiotensin II type 1 (AT1) receptor in visceral white adipose tissue (WAT) is closely implicated in lipid metabolism and energy homeostasis. Recently, perivascular adipose tissue (PVAT) has been shown to play a crucial role in the development of atherosclerosis; however, the effects of AT1 on PVAT properties and their functional relevance in atherogenesis remain undefined. [METHOD AND RESULT] We examined the fat depot-specific difference of adipose tissue among epididymal WAT, PVAT surrounding thoracic aorta, and interscapular brown adipose tissue (BAT) in 8-week-old apoE deficient (apoE-/-) mice. The expression levels of brown adipocyte marker genes (UCP-1, PGC-1α, Elovl3, PPARα, and Cidea) were significantly higher in BAT and PVAT compared with WAT (P<0.01). White adipocyte marker genes (Igfbp3, DPT, Tcf21, and Hoxc9), which were hardly expressed in BAT, showed a moderate expression levels in PVAT, suggesting that PVAT has a strikingly different phenotype from the classical WAT and BAT. We next examined the properties of PVAT in 8-week-old apoE-/-/AT1 receptor deficient (Agtr1-/-) mice. After 4 weeks of western diet, the expression levels of adipocyte differentiation maker genes (PPARγ, FABP4, c/EBPα) were markedly increased in apoE -/- PVAT (P<0.05), which was completely diminished in apoE-/-/Agtr1 -/- PVAT (P<0.01). To investigate the effect of AT1 on the periaortic adipocyte differentiation, we performed primary culture of preadipocyte from stromal vascular fraction in Agtr1 -/- and Agtr1+/+ PVAT. The mRNA expressions of adipocyte differentiation marker genes (PPARγ, FABP4, and c/EBPα) were time-dependently increased in Agtr1+/+ adipocyte. In contrast, FABP4 and c/EBPα mRNA expressions were markedly inhibited in Agtr1 -/- adipocyte, whereas PPARγ did not differ between the two groups during differentiation, suggesting that AT1 is essentially implicated in the terminal differentiation of periaortic adipocyte. [CONCLUSION] Our findings demonstrate that AT1 regulates the expression levels of late stage of adipocyte-differentiation marker genes in PVAT, suggesting that AT1-mediated modulation of periaortic adipocyte differentiation could be a novel therapeutic target for the prevention of atherosclerosis.

scholarly journals Effect of Breed on Transcriptional and Protein Expression of Lipogenic Enzymes in Tail and Subcutaneous Adipose Tissue from Two Grazing Breeds of Lambs

Animals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 64
Author(s):  
María Gallardo ◽  
Luis Arias-Darraz ◽  
Juan Cárcamo
Keyword(s):  
Fatty Acid ◽  
Protein Expression ◽  
Mrna Expression ◽  
Fatty Acid Synthase ◽  
Regulatory Element ◽  
Subcutaneous Fat ◽  
Human Consumption ◽  
Meat Industry ◽  
Lipogenic Enzymes ◽  
Expression Levels

This experiment was carried out to determine the effect of breed on mRNA and protein expression levels of lipogenic enzymes acetyl-CoA carboxylase α (ACC), fatty acid synthase (FAS), stearoyl-CoA desaturase 1 (SCD1) plus sterol regulatory element binding transcription factor 1c (SREBP1c) in the subcutaneous fat (SCF) from the back of the animal, and tail fat (TF) of both Chilota and Suffolk Down lambs grazing Calafatal. Eight Chilota and six Suffolk Down 2-month-old male lambs were allocated to graze a “Calafatal”, a typical secondary succession of Chiloé Archipelago, Chile. After 62 d, lambs were slaughtered according to Chile’s meat industry standards. Fatty acid profile, RT-qPCR, and Western blot analyses from SCF and TF samples were performed. Although the mRNA expression levels of ACC, FAS, SCD1 and SREBP1c in SCF did not differ significantly between breeds (p > 0.05), a trend to higher mRNA expression of FAS and SREBP1c in TF from Chilota lambs was observed (p = 0.06). On the other hand, FAS levels in SCF were higher in Chilota than in Suffolk Down lambs (p < 0.02), although Suffolk Down showed higher fat contents and saturated fatty acid (SFA) proportions than Chilota lambs (p < 0.01). The FAS protein expression in TF was similar in both breeds (p > 0.05). Although the fat content was higher in Suffolk Down than in Chilota lambs (p < 0.01), the SFA proportions were similar in both breeds. Finally, it can be concluded that although mRNA expression of enzymes was similar in both breeds, there were differences in some protein levels in the SCF, partially related with the fatty acid profiles, thus affecting the selection of lamb breed either for human consumption or experimental purposes.

scholarly journals Expression of MTDH and IL-10 Is an Independent Predictor of Worse Prognosis in ER-Negative or PR-Negative Breast Cancer Patients

2020 ◽  
Vol 9 (10) ◽  
pp. 3153
Author(s):  
Pei-Yi Chu ◽  
Shin-Mae Wang ◽  
Po-Ming Chen ◽  
Feng-Yao Tang ◽  
En-Pei Isabel Chiang
Keyword(s):  
Breast Cancer ◽  
Protein Expression ◽  
Mrna Expression ◽  
Cancer Patients ◽  
Expression Patterns ◽  
Hypoxia Inducible Factor ◽  
Tumor Hypoxia ◽  
Tissue Microarrays ◽  
Breast Cancer Patients ◽  
Worse Prognosis

(1) Background: Tumor hypoxia leads to metastasis and certain immune responses, and interferes with normal biological functions. It also affects glucose intake, down-regulates oxidative phosphorylation, and inhibits fatty-acid desaturation regulated by hypoxia-inducible factor 1α (HIF-1α). Although tumor hypoxia has been found to promote tumor metastasis, the roles of HIF-1α-regulated genes and their application are not completely integrated in clinical practice. (2) Methods: We examined the correlation between HIF-1α, metadherin (MTDH), and interleukin (IL)-10 mRNA expression, as well as their expression patterns in the prognosis of breast cancer using the Gene Expression Profiling Interactive Analysis (GEPIA) databases via a web interface; tissue microarrays (TMAs) were stained for MTDH and IL-10 protein expression using immunohistochemistry. (3) Results: HIF-1α, MTDH, and IL-10 mRNA expression are highly correlated and strongly associated with poor prognosis. MTDH and IL-10 protein expression of breast cancer patients usually harbored negative estrogen receptor (ER) or progesterone receptor (PR) status, and late-stage tumors have higher IL-10 expression. With regard to MTDH and IL-10 protein expression status for using univariate and multivariate analysis, the results showed that the protein expression of MTDH and IL-10 in ER-negative or PR-negative breast cancer patients have the worse prognosis. (4) Conclusions: we propose a new insight into hypoxia tumors in the metabolism and immune evidence for breast cancer therapy.

scholarly journals Prognostic value of kallikrein-related peptidase 7 (KLK7) mRNA expression in advanced high-grade serous ovarian cancer

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Weiwei Gong ◽  
Yueyang Liu ◽  
Eleftherios P. Diamandis ◽  
Marion Kiechle ◽  
Holger Bronger ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Mrna Expression ◽  
Protein Level ◽  
Multivariate Analyses ◽  
Expression Patterns ◽  
Mrna Levels ◽  
High Grade ◽  
Serous Ovarian Cancer ◽  
Expression Levels ◽  
Mrna Expression Levels

Abstract Background High-grade serous ovarian cancer (HGSOC) is the most common and lethal subtype of ovarian cancer. A growing body of evidence suggests tumor-supporting roles of several members of the kallikrein-related peptidase (KLK) family, including KLK5 and KLK7, in this cancer subtype. In normal physiology, KLK5 and KLK7 are the major proteases involved in skin desquamation. Moreover, in several cancer types KLK5 and KLK7 co-expression has been observed. Recently, we have shown that elevated KLK5 mRNA levels are associated with an unfavorable prognosis in HGSOC. Therefore, the aim of this study was to investigate the clinical significance of KLK7 mRNA expression and to explore its relation to KLK5 levels in HGSOC. Methods mRNA expression levels of KLK7 were quantified by qPCR in a well-characterized patient cohort afflicted with advanced high-grade serous ovarian cancer (FIGO III/IV, n = 139). Previously determined KLK5 mRNA as well as KLK5 and KLK7 antigen concentrations were used to evaluate the relationship between the expression patterns of both factors on the mRNA as well as protein level in tumor tissue of HGSOC patients. Results There were strong, significant positive correlations between KLK5 and KLK7 both at the mRNA and the protein level, suggesting coordinate expression of these proteases in HGSOC. In univariate analyses, elevated KLK7 levels as well as the combination of KLK5 + KLK7 (high and/or high versus low/low) were significantly associated with worse progression-free survival (PFS). High mRNA expression levels of KLK7 and the combination of KLK5 and KLK7 showed a trend towards significance for overall survival (OS). In multivariate analyses, KLK7 mRNA expression represented an unfavorable, statistically significant independent predictor for PFS and OS. Conclusions The findings imply that both increased KLK5 and KLK7 mRNA expression levels represent unfavorable prognostic biomarkers in advanced high-grade serous ovarian cancer, whereby multivariate analyses indicate that KLK7 mRNA exhibits a stronger predictive value as compared to KLK5 mRNA and the combination of KLK5 and KLK7.

Differences in Expression Patterns of DNMTs and TSG Proteins in Lymphoid Tissue Section Play an Important Role in Their Association

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2657-2657
Author(s):  
Lobna Alkebsi ◽  
Hiroshi Handa ◽  
Kenichi Tahara ◽  
Hiroaki Shimizu ◽  
Takuma Ishizaki ◽  
...  
Keyword(s):  
B Cells ◽  
Protein Expression ◽  
Mrna Expression ◽  
Lymphoid Tissue ◽  
Methylation Status ◽  
Lymphoid Tissues ◽  
Expression Levels ◽  
Protein Expressions ◽  
Mrna Expression Levels ◽  
E Cadherin

Abstract In situ, patterns of expression of DNMTs (DNA methytransferases) in normal reactive tonsillar tissue have been examined. Difference in pattering of expression of DNMTs and TSG (Tumor suppressor genes) proteins in lymphoid tissue section is an important question in relation to their association with each other as well as relationship to mRNA gene expression level. In order to examine this issue, we examined DNMTs and TSG proteins expression by immunohistochemistry in sections of paraffin-embedded specimens obtained from 33 subjects of lymphoma and 16 subjects of Non-malignant tissues after receiving written informed consent. The specimens were stained with anti-DNMTs (DNMT1, DNMT3A and DNMT3B) and anti-TSG (E-cadherin, H-cadherin and ADAMTS18) antibodies. In addition, using fresh-frozen optimal cutting temperature (OCT) compound-embedded tissue specimens before any treatment, we examined mRNA expression levels and promoter methylation status of E-cadherin (CDH1), H-cadherin (CDH13) and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS18) using quantitative real-time PCR (qRT-PCR) and methylation-specific PCR (MSP), respectively. The expression of nuclear DNMTs proteins (DNMT1 and 3A) in lymphoma section was observed in [17/33 (51%); 27/33 (81%)], whereas in non-malignant tissues was [14/16 (87.5%); 13/16 (81%)], respectively. The DNMT3B protein expression was not detected in our tissue samples, which might be explained by the fact that DNMT3B characterized by alternative splicing as shown previously. Membrane proteins (E-cadherin, H-cadherin and ADAMTS18) showed low expression [12/33 (36%); 10/33 (30%); 6/33 (18%), respectively], when compared to non-malignant tissue sections [12/16 (75%); 7/16 (43%); 8/16 (50%), respectively]. The expression levels of CDH1, CDH13 and ADAMTS18 mRNAs were non-significantly reduced in their corresponding protein negative expression compared to the levels in cases with positive protein expression (p =0.112, p =0.378, p =0.077, respectively). We could not find any correlation between mRNA/protein expression levels of DNMTs and the methylation status of CDH1, CDH13 and ADAMTS18. Importantly, by immunostaining especially in non-malignant lymphoid tissues, we found that DNMT1 was highly detected in germinal center B cells (GC B cells) with gradual decrease or no expression in the mantle, marginal, interfollicular and T cells zones. Whereas DNMT3A was preferentially and scattered like expressed in the cells of the surrounding zones out of the germinal centers. Furthermore, E-cadherin, H-cadherin and ADAMTS18 proteins expression were detected on the cell surface membrane of the cells outside the GC but at rates somehow more than those cells inside the GC (Fig. 1). This is supported by the significant association observed between the frequency of DNMT3A with both E-cadherin and ADAMTS18, protein expressions (Chi square: p <0.05), while no association with H-cadherin protein expression. In addition, DNMT1 protein expression did not show significant association with the protein expressions of E-cadherin, H-cadherin and ADAMTS18. Moreover, the mRNA expression levels of DNMT3A and 3B showed high significant levels (p <0.05) in cases with negative protein expressions of both E-cadherin and ADAMTS18 when compared to cases with positive protein expressions (Fig. 2A and C). The DNMT1 mRNA expression level did not show any significant difference between the negative and positive protein expressions of E-cadherin, H-cadherin and ADAMTS18 (Fig. 2B). Furthermore, there was no significant association between the mRNA levels of DNMTs and H-cadherin protein expression. Expression of H-cadherin protein was frequently observed in the endothelial venules and trabeculae of the lymphoid tissues (Fig. 1) which might cause of its lack of association with both DNMT1 and DNMT3A. In conclusion, these results indicate that as a result of differences in pattering of DNMTs and TSG protein expressions detected in lymphoid tissues by immunohistochemistry staining, it might be one of the reasons of the association with each other and their mRNA expression levels across the spectrum of lymphomas and non-malignant lymphoid tissues. Disclosures No relevant conflicts of interest to declare.

The relationships of collagen and ADAMTS2 expressionlevels with meat quality traits in cattle

2016 ◽  
Author(s):  
X. H. Zhang ◽  
H. .Liao ◽  
Y. X. Qi ◽  
Y. Q. Wang ◽  
Y. Z. Pang ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Meat Quality ◽  
Muscle Development ◽  
Expression Patterns ◽  
Subcutaneous Fat ◽  
Biceps Femoris ◽  
Longissimus Dorsi ◽  
Expression Levels ◽  
Longissimus Dorsi Muscle ◽  
Dorsi Muscle

Extracellular matrix (ECM) is the major macromolecule in skeletal muscle, and collagen is main component of ECM surrounding muscle fiber and adipocyte, which affect meat quality greatly. The remodeling of ECM is regulated by matrix metalloproteinases, such as ADAMTS2, which is essential for the maturation of triple helical collagen fibrils in body. The expression patterns of COL1A1, COL2A1, COL3A1 and ADAMTS2 in longissimus dorsi muscle were explored by qRT-PCR and results indicated that the expression levels of COL1A1, COL3A1 and ADAMTS2 were significantly higher at 3 and 24 month, while significantly lower at 12 and 30 month. The expression of ADAMTS2 and COL1A1 had significant positive relationships with intramuscular fat content, while expression of COL3A1 had significant positive relationship with shearing force and water holding capacity in cattle. The expression levels of collagen and ADAMTS2 were significantly higher in mesenteric fat, mammary fat pad and subcutaneous fat than in longissimus dorsi muscle, biceps femoris and infraspinitus tissues. The expressions levels of COL1A1, COL3A1 and ADAMTS2 were significantly lower in marbling fat than in other fat tissues. This study indicated that the expression of collagen and ADAMTS2 had important effects on postnatal skeletal muscle development and meat quality.

Correlation of messenger RNA expression patterns of ERCC1, TS, EGFR, and VEGFR2 with KRAS and BRAF mutational status in advanced colorectal cancer: Implications for targeted therapies.

2013 ◽  
Vol 31 (4_suppl) ◽  
pp. 383-383
Author(s):  
Martin K. H. Maus ◽  
Craig Stephens ◽  
Stephanie H. Astrow ◽  
Peter Philipp Grimminger ◽  
Dongyun Yang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Colorectal Cancer ◽  
Mrna Expression ◽  
Advanced Colorectal Cancer ◽  
Expression Patterns ◽  
Mrna Levels ◽  
Expression Levels ◽  
Mutational Status ◽  
Mrna Expression Levels ◽  
Gene Expression Levels

383 Background: Gene expression levels of ERCC1, TS, EGFR and VEGFR2 may have predictive value for the personalized use of standard chemotherapeutics as well as agents targeting the EGFR and VEGF pathways and the efficacy of EGFR directed monoclonal antibodies like panitumumab and cetuximab has been confirmed to be dependent on wt KRAS and wt BRAF in patients with advanced colorectal cancer. We investigated the correlations between KRAS/BRAF mutational status and the mRNA expression levels of these genes. Methods: Formalin-fixed paraffin-embedded tumor specimens from 600 patients with advanced colorectal adenocarcinoma were microdissected and DNA and RNA was extracted. Specifically designed primers and probes were used to detect 7 different base substitutions in codon 12 and 13 of KRAS, V600E mutations in BRAF and the expression levels of ERCC1, TS, EGFR and VEGFR2 by RT-PCR. Results: Mt KRAS tumors had significantly lower TS and EGFR gene expression levels compared with wt KRAS (p<0,001), whereas mt BRAF tumors showed significantly increased TS and EGFR mRNA levels compared to wt BRAF (p<0,001). Mt BRAF tumors showed significantly higher mRNA levels than mt KRAS tumors (p<0,001). ERCC1 and VEGFR2 mRNA levels were significantly down-regulated in mt KRAS specimen (p<0,001), but showed no significant correlation with BRAF mutational status. Conclusions: KRAS and BRAF mutations are associated with opposite mRNA expression levels for TS and EGFR. Recently, resistance to BRAF inhibition in mt BRAF colorectal tumors has been shown in preclinical models to be associated with up-regulation of EGFR. Our data suggests that BRAF mutants are associated with high EGFR levels at the time of diagnosis, and not necessarily part of an acquired mechanism of resistance. Significantly lower mRNA expression levels of VEGFR2 in mt KRAS tumors may explain lower response to angiogenesis inhibition seen in the TML study.

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