Ephedrae herba, a component of Japanese herbal medicine Mao-to, efficiently activates the replication of latent human immunodeficiency virus type 1 (HIV-1) in a monocytic cell line.

The persistence of latent human immunodeficiency virus type 1 (HIV-1)-infected cellular reservoirs, despite prolonged treatment with highly active antiretroviral therapy (HAART), represents a major hurdle to virus eradication. In this study, we evaluated the effect of Japanese herbal medicine on the induction of HIV-1 replication in latently infected monocytic cell line, U1, in order to eradicate virus efficiently. We found that Mao-to was able to induce HIV-1 replication either alone or in combination with tumor necrosis factor-alpha (TNF-alpha). Among the four components of Mao-to, only Ephedrae herba had strong effects in inducing HIV-1 replication. Analysis by Western blotting revealed that Ephedrae herba induced the nuclear translocation of nuclear factor-kappa B (NF-kappaB). Reporter assay data also showed that Ephedrae herba and, slightly, Mao-to activated the NF-kappaB promoter, indicating that these herbal agents may induce HIV-1 replication through NF-kappaB activation. These findings suggest that Mao-to and its component, Ephedrea herba, may be good candidates to augment HAART by inducing the expression of latent HIV-1 with the ultimate goal of eliminating persistent viral reservoirs in individuals infected with HIV-1.

Heat shock suppresses human NK cell cytotoxicity via regulation of perforin.

Human natural killer (NK) cell, which is an important lymphocyte for immune surveillance, is highly sensitive to heat, but the nature of its response to and its mechanistic regulation by heat remain unclear. Here we determined the effect of in vitro heat shock and in vivo hyperthermia on human NK cell cytotoxicity. Human peripheral blood mononuclear cells (PBMC) obtained from healthy volunteers were subjected to heat shock in vitro (42 degrees C, 1 h). PBMC from cancer patients receiving intentional hyperthermia (42 degrees C, 1 h) for cancer therapy were also obtained. NK cytolytic activity was determined in these samples. NK cell cytotoxicity was down-regulated by heat shock in vitro at 5 h, but at 24 h after heat shock, the NK cytotoxicity was comparable to that with its respective control. Furthermore, we observed that the mRNA and protein expression levels of perforin, which is the cytolytic granule of NK cells, were regulated by heat shock in a similar manner as NK cytotoxicity at 5 h and at 24 h after heat shock. Heat regulation involved the perforin protein in CD56(dim) but not in CD56(bright) NK cell subset. Heat shock neither induced cell death nor altered the expression of some NK activating receptors and adhesion molecules. Moreover, whole-body hyperthermia at 42 degrees C for 1 h of cancer patients also suppressed the cytotoxicity of NK cells but recovered to basal level 1 week after hyperthermia. Heat shock in vitro and in vivo temporarily represses the cytotoxicity of human NK cells.

Vitamins K1 and K2 potentiate hyperthermia by down-regulating Hsp72 expression in vitro and in vivo.

Hyperthermia is used to treat various malignancies, including esophageal, stomach and rectal cancer. Since hyperthermia alone has produced limited results, much attention has been focused on combining hyperthermia with chemotherapy and on searching for substances able to sensitize tumor cells to hyperthermia-induced damage. Here, we show that vitamins K1 and K2 (VK1, VK2) inhibited the expression of heat-shock protein 72 (Hsp72) but did not affect the constitutive expression of Hsc70 or calnexin in vitro and in vivo. VK1 and VK2 sensitized A549 cells to heat-shock induced cell death, while the compounds alone had no effect on cell viability. The suppression of Hsp72 was apparently at the protein level because the mRNA expression of Hsp72 was unchanged. Moreover, the chaperone activity of Hsp72 was compromised after heat-shock when cells were pre-treated with VK2. The effect of VK2 on Hsp72 suppression, however, was also observed in normal mouse tissue after the mice were subjected to whole-body hyperthermia. To eliminate this side effect, local hyperthermia was performed on tumors in mice. The pre-treatment with VK2 potentiated the effect of local hyperthermia on tumor growth suppression. The findings here that VK1 and VK2 inhibit heat-shock-induced Hsp72 suggest their possible use as an adjuvant for hyperthermia in cancer therapy.