Hispidin and its derivatives are widely distributed in edible mushrooms. Hispidin is more cytotoxic to A549, SCL-1, Bel7402 and Capan-1 cancer cells than to MRC5 normal cells; by contrast, hispidin protects H9c2 cardiomyoblast cells from hydrogen peroxide-induced or doxorubicin-induced apoptosis. Consequently, further research on how hispidin affects normal and cancer cells may help treat cancer and reduce chemotherapy-induced side effects. This study showed that hispidin caused caspase-independent death in SGC-7901 cancer cells but not in GES-1 normal cells. Hispidin-induced increases in LC3-II occurred in SGC-7901 cells in a time independent manner. Cell death can be partially inhibited by treatment with ATG5 siRNA but not by autophagy or necroptosis inhibitors. Ultrastructural evidence indicated that hispidin-induced necrotic cell death involved autophagy. Hispidin-induced lysosomal membrane permeabilization (LMP) related to complex cell death occurred more drastically in SGC-7901 cells than in GES-1 cells. Ca2+ rather than cathepsins from LMP contributed more to cell death. Hispidin induced microtubule depolymerization, which can cause LMP, more drastically in SGC-7901 cells than in GES-1 cells. At 4.1 μM, hispidin promoted cell-free tubulin polymerization but at concentrations higher than 41 μM, hispidin inhibited polymerization. Hispidin did not bind to tubulin. Alterations in microtubule regulatory proteins, such as stathmin phosphorylation at Ser16, contributed to hispidin-induced SGC-7901 cell death. In conclusion, hispidin at concentrations higher than 41 μM may inhibit tubulin polymerization by modulating microtubule regulatory proteins, such as stathmin, causing LMP and complex SGC-7901 cell death. This mechanism suggests a promising novel treatment for human cancer.

The estrogen receptor-binding fragment-associated gene 9 (EBAG9) has been identified as an estrogen-responsive gene and was recently identified as a tumor-promoting and prognostic factor for renal cell carcinoma. We investigated whether EBAG9 expression was correlated with primary tumor growth and distant tumor metastasis in a murine breast carcinoma model. Knockdown expression of EBAG9 by small interfering RNA significantly suppressed tumor growth and metastasis in vivo in a highly malignant, spontaneously metastasizing 4T1 mouse mammary carcinoma model. 4T1 cells stably overexpressing EBAG9 developed larger and faster tumor growth and lung metastasis compared with parental 4T1 or 4T1 expressing vector alone. Strong specific cytotoxic T lymphocyte activity and enhanced γ-interferon and interleukin-2 productions were induced in mice that received EBAG9 small interfering RNA therapy. Gene silencing of EBAG9 prolonged the survival of tumor-bearing mice and induced more intensive infiltration of CD8 + T cells in tumor mass. EBAG9 induced apoptosis of T cells, enhanced glycogen synthase kinase 3β phosphorylation and inhibited γ-interferon production of T cells when T lymphocytes were cocultured with 4T1 cells overexpressing EBAG9. Furthermore, overexpression of EBAG9 in 4T1 cells was accompanied with enhanced expression of chemokine (C-X-C motif) receptor 4, which might be involved in tumor metastasis. Taken together, our results suggested that EBAG9 promoted primary 4T1 mammary carcinoma growth and distant metastasis, and EBAG9 small interfering RNA exerted overt regression of tumor growth and metastasis. These findings might provide insights into the mechanism through which tumors evade immunosurveillance and provide a strategy for therapeutic intervention of cancer metastases. (Cancer Sci 2009; 100: 961-969) E BAG9, an estrogen-responsive gene, was identified in MCF-7 human breast carcinoma cell line using a CpG-genomic binding site cloning method.(1) Its product was later found to be identical to RCAS1 (receptor-binding cancer antigen expressed on SiSo cells), a cancer cell-surface antigen implicated in immune escape.(2) EBAG9/RCAS1 expressed in estrogen target organs as well as several other tissues such as brain, liver, and kidney.(2) Published works also showed that EBAG9/RCAS1 was expressed in various malignancies such as breast, ovarian, prostate, and hepatocellular carcinomas.(3-6) RCAS1 reportedly acts as a ligand for a putative receptor present in various human cell lines and peripheral lymphocytes, such as T, B, and NK cells, and thus leads them to apoptosis, which might contribute to the escape of tumor cells from immune surveillance. (7,8) Immunohistochemical studies with tissue samples revealed that RCAS1 expression has been correlated significantly with poor overall survival in patients with several malignancies. (9)(10)(11) Ogushi et al. (12) provided the first in vivo evidence that EBAG9 was a tumor-promoting and prognostic factor for renal cell carcinoma. Their study showed that enhanced tumor gr...

Here, we investigated the antitumor effect of adenovirus-mediated gene transfer of LIGHT, the tumor-necrosis factor (TNF) superfamily member also known as TNFSF14, in the murine A20 B-cell lymphoma. LIGHT gene modification resulted in upregulated expression of Fas and the accessory molecule-intercellular adhesion molecule-1 (ICAM-1) on A20 cells and led to enhanced A20 cell apoptosis. LIGHT-modified A20 cells effectively stimulated the proliferation of T lymphocytes and interferon (IFN)-c production in vitro. Immunization of BALB/c mice with a LIGHT-modified A20 cell vaccine efficiently elicited protective immunity against challenge with the parental tumor cell line. Adenovirus-mediated gene transfer of LIGHT by intratumoral injection exerted a very potent antitumor effect against pre-existing A20 cell lymphoma in BALB/c mice. This adenovirus-mediated LIGHT therapy induced substantial splenic natural killer (NK) and cytotoxic T lymphocyte (CTL) activity, enhanced tumor infiltration by inflammatory cells and increased chemokine expression of CC chemokine ligand 21 (CCL21), IFN-inducible protein-10 (IP-10) and monokine induced by IFN-c (Mig) from tumor tissues. Thus, adenovirus-mediated LIGHT therapy might have potential utility for the prevention and treatment of B-cell lymphoma.

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In this article, published online on 26 April 2010, there was an unintended error in Fig. 2a during proof revision process when submitted higher resolution figures as the typeset company needs, leading to that ICAM-1 FACS staining pictures are the same for A20/LacZ group and A20/LIGHT group. The picture of ICAM-1 FACS staining for A20/LacZ group has now been replaced with the correct picture which was shown in the proof. The corrected Fig. 2a is shown here. We are sorry for the inconvenience caused by this error.