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Astragalus membranaceus is the most popular traditional Chinese medicine for managing vital energy deficiency. Its injectable polysaccharide PG2 has been used for relieving cancer-related fatigue, and PG2 has immune-modulatory and anti-inflammatory effects. In this study, we explored the effects of PG2 in lung adenocarcinoma A549 and CL1-2 cells and investigated its anticancer activity, and the results were validated in severe combined immunodeficiency (SCID) mice. Although PG2 did not inhibit the growth of these cells, it dose-dependently suppressed their migration and invasion, accompanied by reduced vimentin and AXL and induced epithelial cadherin (E-cadherin) expression. Regarding the underlying molecular mechanism, PG2 treatment reduced the macrophage migration inhibitory factor (MIF), an inflammatory cytokine that promotes the epithelial–mesenchymal transition and aggressiveness of cancer cells. Consistent with the previous finding that MIF regulates matrix metalloproteinase-13 (MMP-13) and AMP-activated protein kinase (AMPK), treatment with PG2 reduced MMP-13 and activated AMPK in A549 and CL1-2 cells in this study. In SCID mice injected with A549 cells through the tail vein, intraperitoneal injection with PG2 reduced lung and abdominal metastases in parallel with decreased immunohistochemical staining of AXL, vimentin, MMP-13, and MIF in the tumor. Collectively, data revealed a potential application of PG2 in integrative cancer treatment through the suppression of MIF in cancer cells and their aggressiveness.

Selenium has been intensively studied for the use of cancer prevention and treatment. However, the clinical effects are still plausible. To enhance its efficacy, a combinational study of selenium yeast (SY) and fish oil (FO) was performed in A549, CL1-0, H1299, HCC827 lung adenocarcinoma (LADC) cells to investigate the enhancement in apoptosis induction and underlying mechanism. By sulforhodamine B staining, Western blot and flow cytometric assays, we found a synergism between SY and FO in growth inhibition and apoptosis induction of LADC cells. In contrast, the fetal lung fibroblast cells (MRC-5) were unsusceptible to this combination effect. FO synergized SY-induced apoptosis of A549 cells, accompanied with synergistic activation of AMP-activated protein kinase (AMPK) and reduction of Cyclooxygenase (COX)-2 and &beta, catenin. Particularly, combining with FO not only enhanced the SY-elevated proapoptotic endoplasmic reticulum (ER) stress marker CCAAT/enhancer-binding protein homologous protein (CHOP), but also reduced the cytoprotective glucose regulated protein of molecular weight 78 kDa (GRP78). Consequently, the CHOP downstream targets such as phospho-JNK and death receptor 5 were also elevated, along with the cleavage of caspase-8, -3, and the ER stress-related caspase-4. Accordingly, inhibition of AMPK by compound C diminished the synergistic apoptosis induction, and elevated CHOP/GRP78 ratio by SY combined with FO. The AMPK-dependent synergism suggests the combination of SY and FO for chemoprevention and integrative treatment of LADC.

AIM: To investigate the effect of c9,t11-conjugated linoleic acid (c9,t11-CLA) on the invasion of human gastric carcinoma cell line and its possible mechanism of preventing metastasis. METHODS: Using reconstituted basement membrane invasion, chemotaxis, adhesion, PAGE substrate zymography and RT-PCR assays, we analyzed the abilities of invasion, direct migration, adhesion of intracellular matrix, as well as the activity of type IV collagenase and expression of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 mRNA in SGC-7901 cells which were treated with gradually increased concentrations (25, 50, 100 and 200 μmol/L) of c9,t11-CLA for 24 h. RESULTS: At the concentrations of 200 μmol/L, 100 μmol/L and 50 μmol/L, c9,t11-CLA suppressed the invasion of SGC-7901 cells into the reconstituted basement membrane by 53.7%, 40.9% and 29.3%, respectively, in comparison with the negative control. Only in the 200 μmol/L c9,t11-CLA group, the chemotaxis of SGC-7901 cells was inhibited by 16.0% in comparision with the negative control. C9,t11-CLA also could inhibit the adhesion of SGC-7901 cells to laminin, fibronectin and Matrigel, increase the expression of TIMP-1 and TIMP-2 mRNA, and reduce type IV collagenase activities in the serum-free medium supernatant of SGC-7901 cells. CONCLUSION: c9,t11-CLA can inhibit the invasion of SGC-7901 cells at multiple procedures in tumor metastasis cascade, which may be associated with the induction of TIMP-1 and TIMP-2 mRNA expression.

To study the effects of c9,t11-conjugated linoleic acid (c9,t11-CLA) on invasive ability of human gastric carcinoma cell line (SGC-7901) and to explore its possible mechanism.Reconstituted basement membrane invasion assay was used to evaluate invasive ability of cancer cells. Expression of TIMP-1, TIMP-2 and nm23-H(1) mRNA was measured by reverse transcription polymerase chain reaction (RT-PCR) in SGC-7901 cells.At the concentrations of 200 micromol/L, 100 micromol/L and 50 micromol/L, c9,t11-CLA suppressed their reconstituted basement membrane invasion of SGC-7901 by 53.7%, 40.9% and 29.3%, respectively. c9,t11-CLA could induce the expression of TIMP-1, TIMP-2 and nm23-H(1) mRNA in SGC-7901 cells.The invasion of SGC-7901 cells could be inhibited by c9,t11-CLA through reconstituted basement membrane. Anti-invasion action of c9,t11-CLA might be associated with induction of expression of TIMP-1, TIMP-2 and nm23-H(1) mRNA in tumor cells.

To determine the effect of apoptosis on gastric cancer cells (SGC-7901) induced by cis-9, trans-11-conjugated linoleic acid (c9, t11-CLA) and its possible mechanism in the inhibition of cancer cells growth.Using cell culture, flow cytometery and immunocytochemical techniques, we examined the cell growth, frequency of apoptosis and distribution of cell cycle, expression of ki67, bcl-2, Fas, and c-myc of SGC-7901 cells which were treated with various c9, t11-CLA concentrations (25,50,100 and 200 micromol x L(-1)) of c9, t11-CLA for 24 h and 48 h, with a negative control (0.1 % ethanol).The growth of SGC-7901 cells was inhibited by c9,t11-CLA. Eight days after treatment with various concentrations of c9,t11-CLA, as mentioned above, the inhibition rates were 5.9 %, 20.2 %,75.6 % and 82.4 %, respectively. The frequency of apoptosis on SGC-7901 cells induced by different concentrations of c9, t11-CLA (except for 25 micromol.L(-1), 24 h) was significantly greater than that in the negative control (P0.01). To further investigate the influence of the cell cycle progression, we found that apoptosis induced by c9, t11-CLA may be involved in blocking the cell cycle of SGC-7901 cells. Immunocytochemical staining demonstrated that SGC-7901 cells preincubated in media supplemented with different c9, t11-CLA concentrations for various time periods significantly decreased the expressions of ki67 (the expression rates were 18.70-3.20 %, at 24 h and 8.10-0.20 % at 48 h, respectively), bcl-2 (4.30-0.15 % at 24 h and 8.05 %-0 at 48 h), and c-myc (4.85-2.20 % at 24 h and 4.75-0.30 % at 48 h) as compared with those in the controls (the expressions of ki67, bcl-2, and c-myc were 15.1 % at 24 h and 13.5 % at 48 h, 6.80 % at 24 h and 8.00 % at 48 h, 5.50 % at 24 h and 5.30 % at 48 h, respectively) (P0.01), whereas the expressions of Fas were increased (0.60-2.75 %, 24 h and 0.45-5.95 %, 48 h).The growth and proliferation of SGC-7901 cells are inhibited by c9, t11-CLA via blocking the cell cycle, pathways of bcl-2-associated mitochondria with reduced expression of bcl-2 and Fas-associated death domain protein (FADD) with enhanced expression of Fas. But expression of c-myc on SGC-7901 cells is lower than that in negative control, which needs to be studied further.

AIM: To determine the effect of cis-9, trans-11-conjugated linoleic acid (c9,t11-CLA) on the cell cycle of gastric cancer cells (SGC-7901) and its possible mechanism in inhibition cancer growth. METHODS: Using cell culture and immunocytochemical techniques, we examined the cell growth, DNA synthesis, expression of PCNA, cyclin A, B1, D1, P16ink4a and P21cip/waf1 of SGC-7901 cells which were treated with various c9,t11-CLA concentrations (25, 50, 100 and 200 μmol•L⁻¹)of c9,t11-CLA for 24 and 48 h, with a negative control (0.1% ethane). RESULTS: The cell growth and DNA synthesis of SGC-7901 cells were inhibited by c9,t11-CLA. SGC-7901 cells. Eight day after treatment with various concentrations of c9,t11-CLA mentioned above, the inhibition rates were 5.92%, 20.15%, 75.61% and 82.44%, respectively and inhibitory effect of c9,t11-CLA on DNA synthesis (except for 25 μmol/L, 24 h) showed significantly less 3H-TdR incorporation than that in the negative controls (P < 0.05 and P < 0.01). Immunocytochemical staining demonstrated that SGC-7901 cells preincubated in media supplemented with different c9,t11-CLA concentrations at various times significantly decreased the expressions of PCNA (the expression rates were 7.2%-3.0%, 24 h and 9.1%-0.9% at 48 h, respectively), Cyclin A (11.0%-2.3%, 24 h and 8.5%-0.5%, 48 h), B1 (4.8%-1.8% at 24 h and 5.5%-0.6% at 48 h)and D1 (3.6%-1.4% at 24 h and 3.7%-0% at 48 h) as compared with those in the negative controls (the expressions of PCNA, Cyclin A, B1 and D1 were 6.5% at 24 h and 9.0% at 48 h, 4.2% at 24 h and 5.1% at 48 h, 9.5% at 24 h and 6.0% at 48 h, respectively) (P < 0.01), whereas the expressions of P16ink4a and P21cip/waf1, cyclin-dependent kinases inhibitors (CDKI), were increased. CONCLUSION: The cell growth and proliferation of SGC-7901 cell is inhibited by c9,t11-CLA via blocking the cell cycle, with reduced expressions of cyclin A, B1 and D1 and enhanced expressions of CDKI (P16ink4a and P21cip/waf1).