Biomedical subjects

Jianmin Chen

Publications and source records attributed to Jianmin Chen.

24 records · Page 2Linked to original sources

PubMed2003

Lignans and tamoxifen, alone or in combination, reduce human breast cancer cell adhesion, invasion and migration in vitro.

Flaxseed has been shown to reduce the metastasis of estrogen receptor negative (ER-) human breast cancer in nude mice. This study determined whether enterodiol (ED) and enterolactone (EL), metabolites of plant lignans exceptionally rich in flaxseed, and tamoxifen (TAM), alone or in combination, can influence the various steps of metastasis, that is, breast cancer cell adhesion, invasion and migration, of two ER- human breast cancer cell lines, MDA-MB-435 and MDA-MB-231. The inhibition by ED, EL or TAM (1-5 microM) of cell adhesion to Matrigel or extracellular matrices, fibronectin, laminin, and type IV collagen, as well as cell invasion was dose dependent in both cell lines. When ED, EL and TAM were combined at 1 microM, a greater inhibitory effect on cell adhesion and invasion was observed than with either compound alone. ED and EL at doses of 0.1-10 microM reduced cell migration, but TAM had no effect at 0.1 and 1 microM, and exhibited a stimulatory effect at 10 microM. It is concluded that lignans and TAM, alone or in combination, can inhibit the steps involved in the metastasis cascade. Although more investigations are required, the study also suggests that the intake of the lignan-rich flaxseed may not antagonize the effect of TAM in ER- breast cancer cells.

4-Butyrolactone↗

PubMed2003

Exposure to flaxseed or its purified lignan during suckling inhibits chemically induced rat mammary tumorigenesis.

Previous studies have shown that feeding flaxseed (FS) or its lignan secoisolariciresinol diglucoside (SDG) to rat dams during lactation enhances the differentiation of rat mammary gland in the female offspring. This study determined whether exposure to a diet with 10% FS or SDG (equivalent to the amount in 10% FS) during suckling could protect against 9,10-dimethyl-1,2-benzanthracene (DMBA)-induced rat mammary tumorigenesis later in life. Dams were fed the AIN-93G basal diet (BD) throughout pregnancy. After delivery, dams were randomized to continue on BD or were fed BD supplemented with 10% FS or SDG during lactation. Three-day urine of dams was analyzed for mammalian lignans. After weaning, all offspring were fed BD. At postnatal Days 49 to 51, during proestrus phase, offspring were gavaged with 5 mg of DMBA. At Week 21 post-DMBA administration, compared with the BD group, the FS and SDG groups had significantly lower (P < 0.05) tumor incidence (31.3% and 42.0% lower, respectively), total tumor load (50.8% and 62.5% lower, respectively), mean tumor size (43.9% and 67.7% lower, respectively), and tumor number (46.9% and 44.8% lower, respectively) per rat. There was a significant decreasing trend (P < 0.05) in final tumor weights in rats fed FS or SDG. The high urinary lignan excretion in dams fed with FS or SDG corresponded with the reduced tumor development. The FS and SDG groups did not differ significantly in tumor indices, indicating that the effect of FS is primarily due to its SDG. There were no significant changes in selective reproductive indices measured among dams and offspring. In conclusion, exposure to FS or SDG during suckling suppressed DMBA-induced rat mammary tumorigenesis, suggesting that exposure to lignans at this early stage of mammary gland development reduces susceptibility to mammary carcinogenesis later in life without adverse effects on selective reproductive indices in dams or offspring.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed2002

Flaxseed inhibits metastasis and decreases extracellular vascular endothelial growth factor in human breast cancer xenografts.

Angiogenesis is important in tumor growth, progression and metastatic dissemination. Vascular endothelial growth factor (VEGF) is one key factor in promotion of breast cancer angiogenesis. VEGFs are bioactive in the extracellular space where they become available to the endothelial cells. Phytoestrogens such as lignans have been shown to alter breast cancer incidence and be cancer-protective in rats. We show that supplementation of 10% flaxseed, the richest source of mammalian lignans, to nude mice with established human breast tumors reduced tumor growth and metastasis. Moreover, flaxseed decreased extracellular levels of VEGF, which may be one mechanistic explanation to the decreased tumor growth and metastasis.

Animals↗

PubMed2002

Detection of antibodies to human immunodeficiency virus (HIV) that recognize conformational epitopes of glycoproteins 160 and 41 often allows for early diagnosis of HIV infection.

On the basis of human immunodeficiency virus (HIV) needlestick studies, the time to seroconversion for anti-HIV antibodies is 1-9 months (mean, approximately 2-3 months). However, an earlier marker of an immune response to HIV often occurs-serum anti-HIV antibodies reactive with live HIV-infected cells, termed "early HIV antibodies." The specificities of these antibodies are characterized by the recognition of type-specific conformational epitopes of the HIV envelope glycoprotein (gp) 160 and gp41. By use of a third-generation native HIV(IIIB) gp160 enzyme immunoassay (EIA), detection of HIV antibodies occurred, on average, 33 days earlier than did detection by commercial EIA and 25 days earlier than did detection by the reference antigen and reverse-transcription polymerase chain reaction (RT-PCR) assays in 3 of 5 HIV seroconversion panels. A fourth panel possessed early HIV antibodies that reacted with HIV(213) but not with HIV(IIIB), allowing for detection of HIV antibodies approximately 3 weeks earlier than by RT-PCR or other current tests.

Blotting, Western↗

PubMed2002

Dietary flaxseed inhibits human breast cancer growth and metastasis and downregulates expression of insulin-like growth factor and epidermal growth factor receptor.

Recent studies indicate that diets rich in phytoestrogens and n-3 fatty acid have anticancer potential. This study determined the effect of flaxseed (FS), the richest source of lignans and alpha-linolenic acid, on growth and metastasis of established human breast cancer in a nude mice model. Estrogen receptor-negative human breast cancer cells, MDA-MB-435, were injected into the mammary fat pad of mice (Ncr nu/nu) fed a basal diet (BD). At Week 8, mice were randomized into two diet groups, such that the groups had similar tumor size and body weight. One continued on the BD, while the other was changed to BD supplemented with 10% FS, until sacrifice at Week 15. A significant reduction (P < 0.05) in tumor growth rate and a 45% reduction (P = 0.08) in total incidence of metastasis were observed in the FS group. Lung metastasis incidence was 55.6% in the BD group and 22.2% in the FS group, while the lymph node metastasis incidence was 88.9% in the BD group and 33.3% in the FS group (P < 0.05). Mean tumor number (tumor load) of total and lymph node metastasis was significantly lower in the FS than in the BD group (P < 0.05). Metastatic lung tumor number was reduced by 82%, and a significantly lower tumor trend (P < 0.01) was observed in the FS group. Lung weight, which also reflects metastatic tumor load, in the FS group was reduced by 20% (P < 0.05) compared with the BD group. Immunohistochemical study showed that Ki-67 labeling index and expression of insulin-like growth factor I and epithelial growth factor receptor in the primary tumor were lower in the FS (P < 0.05) than in the BD group. In conclusion, flaxseed inhibited the established human breast cancer growth and metastasis in a nude mice model, and this effect is partly due to its downregulation of insulin-like growth factor I and epidermal growth factor receptor expression.

Animals↗

PubMedDate not supplied

Simultaneous determination of seven compounds in snow lotus herb using high-performance liquid chromatography.

A reversed-phase high-performance liquid chromatographic method is developed for the quantitative determination of seven components of Snow Lotus Herb (Saussurea tridactyla Sch.-Bip.ex Hook.f.): umbelliferonglucoside, luteolin-7-O-beta-D-glucoside, rutin, apigenin-7-O-beta-D-glucoside, kaempferol-3-O-beta-D-glucoside, apigenin-7-O-beta-D-rutinoside, and luteolin. Samples are analyzed by means of a reverse-phase column (Diamonsil C(18)) using methanol and water under gradient conditions as the mobile phase for 60 min. This method offers selectivity, accuracy, precision, linearity, and ruggedness, as well as efficiency and ease.

Chromatography, High Pressure Liquid↗