Glucocorticoids are effective to treat lymphoma and leukemia. Their effect in colon cancer remains far from clear. Here, we found that glucocorticoid receptor (GR) α protein level was dramatically lower in colon cancer than in lymphoma. Colon cell lines LoVo and HCT116 were GRα-rich and GRα was not detectable in HT29 or SW480. Dexamethasone significantly inhibited cell growth of GRα-rich cell lines and did not significantly affect GRα-negative cell lines. Dexamethasone induced apoptosis and increased chemosensitivity of GRα-rich cell lines. Knockdown of GRα significantly attenuated dexamethasone effects on cell growth, apoptosis and chemosensitivity. NF-κB p65 significantly correlated with GRα in colon cancer samples. Dexamethasone decreased NF-κB p65 activity. Knockdown of NF-κB p65 increased apoptosis. Our data demonstrate GRα protein level is dramatically lower in colon cancer than in lymphoma. Dexamethasone inhibits cell growth, induces apoptosis and enhances chemosensitivity in colon cancer, at least partly, via GRα and NF-κB.

The motivation of this paper comes from an open question: which graphs have regular endomorphism monoids? In this paper, we give a definitely answer for unicyclic graphs, proving that a unicyclic graph [Formula: see text] is End-regular if and only if, either [Formula: see text] is an even cycle with 4, 6 or 8 vertices, or [Formula: see text] contains an odd cycle [Formula: see text] such that the distance of any vertex to [Formula: see text] is at most 1, i.e., [Formula: see text]. The join of two unicyclic graphs with a regular endomorphism monoid is explicitly described.

The zero-divisor graph of a non-commutative ring R, written as , is a directed graph with vertex set of all non-zero zero-divisors of R, and there is a directed edge from a vertex x to a distinct vertex y if and only if . Let M(n, q) (resp., T(n, q)) be the ring of all matrices (resp., upper triangular matrices) over a finite field . Recently, Wang (Linear Algebra Appl. 2015;465:214–220) determined the automorphisms of the zero-divisor graph of T(n, q). In this paper, we determine the automorphisms of , extending the result due to L. Wang from T(n, q) to M(n, q). Since the case is trivial, and the case has been examined in Ma et al. (J. Korean Math. Soc. 2016;53:519–532), we just determine the automorphisms of in the case. We show that a bijective map on is an automorphism of if and only if there exist invertible matrices and a such that for any , where , and depend on A, and .

The zero-divisor graph of a noncommutative ring R, denoted by ( R), is a graph whose vertices are nonzero zero-divisors of R, and there is a directed edge from a vertex x to a distinct vertex y if and only if xy = 0. Let R = M2(Fq) be the 2×2 matrix ring over a finite field Fq. In this article, we investigate the automorphism group of ( R).

Let be a finite field with q elements, be the ring of all matrices over , Z(R) be the set of all zero-divisors of R, i.e. Z(R) consists of all singular matrices over . The total graph of , denoted by , is a graph with all elements of R as vertices, and two distinct vertices are adjacent if and only if . In this paper, we determine the automorphisms of the total graph for .

Let F q be a finite field with q elements, n(≥2) a positive integer, and T n (q) the semigroup of all n × n upper triangular matrices over F q . The generalized Cayley graph GCay(T n (q)) of T n (q) is a directed graph with vertex set T n (q), in which there is a directed edge from a vertex A to a distinct vertex B if and only if B = XAY for some X, Y ∈ T n (q). The main result of this article proves that a bijective map σ is an automorphism of GCay(T n (q)) if and only if, for any vertex A of GCay(T n (q)), either σ(A) = P A AQ A or σ(A) = P A JA t JQ A , where A t denotes the transpose of A, , and P A and Q A are invertible upper triangular matrices depending on A.

Let n be a positive integer and R be a unital commutative ring with 2 invertible. By M-n(R), we mean the algebra consisting of all n x n matrices over R, and by e, we denote the identity matrix in M-n(R). We call x is an element of M-n(R) an involutory matrix if x(2) = e. The Jordan product 'o' is defined by x o y = 1/2 (xy + yx). A linear transformation. on M-n(R) is called derivable (resp., Jordan derivable) at involutory matrices if phi(x)x + x phi(x) = phi(e) (resp., phi(x) o x + x o phi(x) = phi(e)) for any involutory matrix x. In this paper, we show that a linear transformation phi on M-n(R) is derivable, or Jordan derivable, at involutory matrices if it is an inner derivation.

Let Fq be a finite field with q elements, n(≥2) a positive integer, Matn(q) the set of all n×n matrices over Fq, R(n,q) the set of all rank one upper triangular matrices in Mat(n,q). The zero-divisor graph of Matn(q), written as Γ(Matn(q)), is a directed graph with vertex set all nonzero zero-divisors of Matn(q), and there is a directed edge from a vertex A to a vertex B, written as A→B, if and only if AB=0. In this paper, we determine the automorphisms of an induced subgraph, written as Γ(R(n,q)), of Γ(Matn(q)) with vertex set R(n,q). The main theorem of this article proves that a bijective map σ on R(n,q) with n≥3 is an automorphism of Γ(R(n,q)) if and only ifσ(X)=aXP−1[π(xij)]P,∀X=[xij]∈R(n,q), where aX∈Fq⁎ depends on X; P is an invertible upper triangular matrix; π is an automorphism of the field Fq, [π(xij)] denotes the matrix whose (i,j)-entry is π(xij).

目的:检测糖皮质激素受体在结肠癌组织及细胞株中的表达,探讨地塞米松共处理或预处理24h,结肠癌细胞株对奥沙利铂和氟脲嘧啶化疗敏感性的变化.方法:采用免疫组化检测糖皮质激素受体在61例结肠癌组织标本及4种结肠癌细胞株中的表达;Hoechst33342染色、流式细胞仪检测体外地塞米松对结肠癌细胞株的凋亡诱导作用;以MTT法检测地塞米松共处理或预处理24h后.结肠癌Lovo细胞株对奥沙利铂和氟脲嘧啶化疗敏感性的变化.结果:在57.3%的结肠癌组织标本中糖皮质激素受体呈阳性表达,在四种结肠癌细胞株中仅Lovo和HCT-116表达糖皮质激素受体,HT-29和SW-480细胞不表达.单独应用地塞米松后,对糖皮质激素受体阳性的Lovo和HCT-116细胞有较强的促凋亡作用,对不表达糖皮质激素受体的HT-29和SW-480细胞作用则不明显.以1×10~(-4)mol/L的地塞米松处理Lovo细胞24h,或与奥沙利铂共处理可使奥沙利铂的IC50从(13.7±1.3)μg/mL降低至(5.9±0.6)μg/mL和(4.8±0.7)μg/mL;同样处理可使氟脲嘧啶的IC50从(72.2±8.1)μg/mL降低至(21.1±4.1)μg/mL和(18.6±4.0)μg/mL.结论:部分结肠癌组织及细胞株表达糖皮质激素受体.地基米松体外作用能够促进糖皮质激素受体阳性的结肠癌细胞发生凋亡,与奥沙利铂和氟脲嘧啶预处理或共处理后可以增加结肠癌细胞的化疗敏感性.

OBJECTIVE:To examine the expression of glucocorticoid receptor in human colon carcinoma samples and cell lines,explore the effects of GR on the colon cancer cells in vitro,and attempt to define the functional role of GRβ during the steroid response.METHODS:The GR expression was investigated in colon carcinoma tissue samples and cell lines by using immunohistochemical assays.The effects of dexamethasone(Dex)on colon cancer cells were detected by MTT and annexinⅤ-FITC/PI FCM.The regulation of GRα and GRβ by Dex was analyzed by RT-PCR.The effects of silencing GRβ mRNA on Dex-induced apoptosis were assessed.RESULTS:GR was expressed in 57.3% of colon carcinoma and in LoVo and HCT116,not in HT29 and SW480.Dex inhibited cell growth and induced apoptosis in the GR-positive LoVo and HCT116 cells.The expressions of both GRα and GRβ mRNA increased than their basal expression levels with Dex treatment,and the expression of GRβ increased more significantly.The mRNA expression of GRβ decreased by 67.3% in LoVo cells with liposome-mediated transfection of synthesized GRβ siRNA and its rate of Dex-induced apoptosis increased from(34.7±1.8)% to(45.4±4.3)%(P0.05).CONCLUSION:The inhibitions of proliferation and apoptosis do occur on the GR-positive colon carcinoma cells induced by Dex in vitro,and elevated GRβ may inhibit cells' response to steroids.

Objective To explore the role and influence of inhibiting the neuropilins-2 (NRP2) expression on the tubular formation of human lymphatic tube endothelial cells (LECs) in vitro. Methods Human LECs were isolated and purified from freshly excised human foreskins,and they were identified. The NRP2-RNAi/LECs group and mock/LECs group were respectively transfected with pGensil-NRP2 (a plasmid combined with NRP2 siRNA) and pGensil-1 (empty plasmid),and the hECs group consisting of normal LECs. RT-PCR and Western blotting were applied to detect the mRNA and protein expressions of NRP2. The difference in cell proliferation was reflected in cell growth curves. LECs were cultured with three-dimensional cultivation method,and the quantity of tubular structures,external and internal diameters of tubes,and thickness of tube wall were calculated. Results The NRP2 expression significantly declined in NRP2-RNAi/LECs group compared with that of both hECs group and mock/LECs group (P<0.05),while no significant difference was found between the two latter groups (P>0.05). The growth curves showed no difference in proliferation among the three groups,the cells achieved the exponential phase within 3-5 days and a lag phase within 6-7 days. Lymphatic tubular structure was seldom observed,but only budding was sometimes found in the NRP2-RNAi/LECs group,in which the number of tubal structure,external and internal diameters of tubes,and thickness of tube wall were less and lower than that in the mock/LECs group and hECs group (P<0.05),while no significant difference on those parameters was found between the two latter groups (P>0.05). Conclusion Down-regulation of NRP2 expression may suppress the lymphatic tube formation in vitro,thereafter inhibit the formation of lymphatic vessels in tumor.

Objective:To explore the role and influence of inhibition neuropilins-2(NRP2) expression on lymphangiogenesis and metastasis in colorectal carcinoma. Methods:To downregulate NRP2 expression by RNA interference. To transfection NRP2 RNAi vector into LoVo cells and transplanted into nude mouses. After havesting the xenotransplant neoplasm respectively 4,6、8、12 weeks, the expression of NRP2 and proliferation, and the lymphantic density, lymphonode metastasis and distance organ metastasis in the xenotransplant tumor were dectected and compared with the control group. Results:An orthotopic transplantation model of human primary colorectal cancer was successfully established in nude mice, which could completely repeat the natural clinicopathologic course of human primary colorectal cancer, and metastasis pattern of the model was similar to that of clinical patients. It significantly decreased the lymphantic density, lymphonode metastasis and distance organ metastasis in the xenotransplant tumor of LoVo cells, which downregulated NRP2 expression. Conclusion:To inhibite lymphangiogenesis and the metastasis in colorectal carcinoma by downregulating NRP2 expression, it may be a potential target of therapy for tumors.

BACKGROUND/AIMS:Extensive trials have indicated that cancer cells with high glycolytic activity exhibit decreased sensitivity to anticancer agents. Moreover, recent research has proved that a specific inhibitor of hexokinase II, which is a key glycolytic enzyme, may enhance the activity of anticancer drugs. The purpose of this study is to further investigate the effect and mechanisms of hexokinase II on chemosensitivity of colon cancer cells to 5-fluorouracil.METHODOLOGY:The expression of hexokinase II gene was down regulated by RNA interference in colon cancer cell line LoVo, then the IC50 value of 5-fluorouracil to LoVo cells was carried out by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and the protein expression of hexokinase II and thymidylate synthas by Western blot analysis Meanwhile, cell apoptosis and mitochondrial membrane potential were assessed by flow cytometry. Caspase-3 activity was also determined by its substrate color reaction.RESULTS:Down-regulation of the hexokinase II gene of LoVo cells resulted in decreased IC50 value of 5-fluorouracil and increased apoptosis rate, respectively. Furthermore, silencing hexokinase II of LoVo cells induced loss of mitochondrial membrane potential, activation of caspase-3, and inhibition of thymidylate synthase expression.CONCLUSIONS:Our findings suggest targeting hexokinase II has a potential role in the combination 5-fluorouracil treatments of colon cancer.

Objective:After knocking down the expression of hexokinase-Ⅱ(HK-Ⅱ) gene with RNA interference(RNAi) technique,chemotherapeutical effect and mechanism on colon cancer LoVo cell were investigated.Methods:In order to inhibit expression of HK-Ⅱ,a shRNA eukaryotic expression vector was constructed and transfected into LoVo cells.The mRNA and protein expression of HK-Ⅱ gene were assessed using semi-quantitive RT-PCR and Western blot analysis respectively.Then IC50 of LoVo cells by 5-FU and L-OHP were also assessed using MTT assay.The activation of caspase-3 was detected by substrate color reaction.Furthermore,the protein expression of thymidylate synthase(TS) was detected by Western blot analysis.Results:The expression of HK-Ⅱ gene was efficiently blocked by RNAi.The expression inhibition rates were 72.1% and 71.2% at mRNA and protein levels of LoVo cells respectively.The IC50 of 5-FU and L-OHP of the cells transfected with plasmids encoding HK-Ⅱ shRNA were(4.70±0.40)μg/ml and(6.27±0.59)μg/ml respectively,which were significantly lower than that of the normal cultured LoVo cells,(11.93±0.15)μg/ml and(9.77±0.60)μg/ml respectively(P0.01).Compared with those of the normal cultured LoVo cells,the activation of caspase-3 were increased significantly and the protein expression of TS was decreased in the the cells transfected with plasmids encoding HK-Ⅱ shRNA plasmids respectively.Conclusion:Selective knock-down of the HK-Ⅱ gene expression can significantly enhance chemotherapeutical effect of LoVo cell via activation of caspase-3 and decreased expression of TS protein.

Let R be a commutative ring with identity, M-n(R) the R-algebra consisting of all n by n matrices over R. In this article, for n >= 5 we classify linear maps phi from M-n(R) into itself satisfying phi(x)x + x phi(x) = 0 whenever x(2) = 0. We call such maps as square-zero derivations.

Objective:To explore the role of neuropilin-2(NRP2) expression in colorectal cancer tissue lymphangiogenesis and metastasis.Methods:Detected the expression of NRP2,and VEGF-C with immunohistochemical and reverse transcription-polymerase chain reaction(RT-PCR) analysis,furthermore,detected the micro-lymphantic density(MLD) with immunohistochemical analysis.The results were analyzed statistically to investigate the correlations of NRP2 and VEGF-C expression with lymphonode metastasis,and MLD,and some other clinical pathology characterictics.Results:The significant differences of MLD were among those of tumor margin(48.8±23.5),superficial tumor region(24.6±10.1) and tumor center(11.3±7.7)(P0.05).The mRNA level of NRP2 in tumor tissue(0.87±0.26) was higher than that(0.38±0.12) in normal tissue(P0.01).The mRNA level of NRP2(1.12±0.25)in tumor tissue of metastasis group was higher than that(0.76±0.19) in non-metastasis group(P0.01).The expression of NRP2 were location on cytoplasm in tumor cells and some lymphantic endothelial cells(LECs),it's expression rate was 34.8%.Their MLD were correlated with expression positive strength of NRP2(r=0.432,P0.01).The expression of NRP2 was association with lymphatic node metastasis,and differentiation degree,and Dukes stage and infiltrative degree of tumors(P0.05).The expression of NRP2 in colorectal cancer tissue was positively correlated with expression of VEGF-C(r=0.606,P=0.001).Conclusion:The expression of NRP2 in colorectal cancer tissue is associated with lymphangiogenesis and lymph nodes metastasis in colorectal carcinoma.

Objective: To investigate the relationship between Tiam1 and lymphangiogenesis in human colorectal carcinoma (CRC) tissues, as well as the expression of VEGF-C in a CRC cell line (HCT116) after knockdown of the Tiam1 gene with RNA interference (RNAi).Results: In the specimens of CRC tissue, the positivity rate of Tiam1 and VEGF-C was 84% and 58%, respectively. The positivity rate of VEGF-C in the Tiam1 positive group (64.3%) was significantly higher than that in the Tiam1 negative group (25.0%). The LMVD in the Tiam1 positive group (11.35 +/- 3.34) was significantly higher than that in the Tiam1 negative group (7.38 +/- 2.27). In addition, the expression of the Tiam1 gene was efficiently blocked by RNAi. Downregulation of Tiam1 gene expression significantly suppressed HCT116 cell growth in vitro. Compared with untransfected HCT116 cells, HCT116 cells transfected with pGenesil-1-Tiam1 plasmids showed a significant decrease in the expression of VEGF-C.Methods: The expressions of Tiam1, Rac1, VEGF-C and Podoplanin in 50 samples of CRC were detected by immunohistochemical analysis. The lymph microvessel density (LMVD) in Podoplanin positive specimens was evaluated. The results were analyzed statistically to investigate the correlation of Tiam1, VEGF-C, lymph node metastasis and other clinicopathological parameters. An shRNA eukaryotic expression vector against Tiam1 gene was constructed and transfected into HCT116 cells. The expression of Tiam1 gene was assessed by RT-PCR and western blot analysis.Conclusions: We suggest that the Tiam1 gene may act as a crucial therapeutic target for Lymphangiogenesis in CRC.

Objective To study the effect of HCT116,transfected by Tiam1-SiRNA plasmid,on the lymphangiogenesis of transplantation tumor in nude mouse,and to investigate the relationship between the expression of Tiam1 and lymphangiogenesis.Methods Ten node mice were devided into two groups: Tiam1-SiRNA group and control group.The transfected HCT116 cells and control HCT116 cells were inoculated to nude mice right back subcutaneously.Five weeks later,the transplantation tumors were taken.The expressiong of Tiaml,Racl,VEGF-C,VEGF-D and lymphangiogenesis between the two groups were examined using immunohistochemistry methods(SP) and Western blot.Results Tiam1,Rac1 and VEGF-C/D expression were lower in tranfected tumor than those in control tumor.LMVD in transfected tumor 2.2±1.31 was also reduced than that in control tumor 6.8±2.86.Conclusion Tiam1-SiRNA can inhibited lymphangiogenesis in colorectal cancer of nude mouse by its effect on VEGF-C/D in local microenvironment.