Inhibition of tumor metastasis by carrageenan-induced granulomas

Fucoxanthin induces apoptosis in human cervical cancer cell line HeLa via PI3K/Akt pathway

Cervical cancer (CC) is a malignant neoplasm arising from cells originating in the cervix uteri, among the top causes of death from cancer in women. In a gene expression profiling study of metabolic response to treatment, PI3K/Akt signaling pathway are associated with the development of CC. A common mechanism of Akt activation seen in cancer types is alterations in the upstream regulators of Akt such as phosphatidylinositol 3-kinase (PI3K), which is overexpressed in cervical cancer tissues, and leads to phosphorylation of Akt. Both PI3K and Akt inhibitors exist and may be therapeutically valuable. In the present study, we use MTT assay and western blot for the high-throughput screening to select specific inhibitors of PI3K/Akt signaling pathway, and then obtain fucoxanthin. Fucoxanthin is a water-soluble dietary fiber, taken from the unique slimy component of alginic cells. Various studies have pointed out that fucoxanthin is very effective for the treatment of cancer. Our results have shown that fucoxanthin induced a significant apoptosis of HeLa cells, compared with other candidates. After treatment with fucoxanthin for 24 h, the level of phosphorylation was inhibited in a dose-dependent manner, and the proteins of apoptotic markers were changed in HeLa cells. And fucoxanthin could suppress tumor growth in vivo. In addition, the mitochondrial signal transduction pathway maybe was involved in its mechanism and NF-κB activation was decreased after treatment with fucoxanthin. Therefore, fucoxanthin may be used as anti-cervical cancer drugs in the future.

Eicosanoid synthesis by alveolar macrophages in rats with malignant mammary tumors: differences in rats treated with and without carrageenan implants

Eicosanoid synthesis by alveolar macrophages (AM), harvested from tumor bearing animals, was measured after tumor inoculation in rats treated with or without carrageenan (carra), an immunomodulating agent. After incubation of the cells with [14]C-arachidonic acid and the Ca-ionophore A23187, samples were measured by high pressure liquid chromatography (HPLC). From the HPLC profiles the lypoxygenase products, 12-hydroxyeicosatetraenoic acid (12-HETE), 15-HETE, and leukotriene-B4 (LTB4) were determined as well as the cyclooxygenase products, prostaglandin (PG)E2, PGF2 alpha and TXB2. After tumor inoculation AM-synthesis of lipoxygenase products tended to increase to values twice those of the base line values, whereas cyclooxygenase products showed subnormal values. In the non treated animals, 10 days after tumor inoculation, statistically significant increases in 12- and 15-HETE, LTB4 and PGE2 were observed when compared with carra treated animals. Later measurements did not show these differences in AM metabolism. AM metabolism was (negatively) correlated with the number of macrophages, which was particularly evident in the correlation with 12-HETE synthesis.