Keiji Yoshinaga

Alcohol drinking, cigarette smoking, and the development of squamous cell carcinoma of the esophagus: epidemiology, clinical findings, and prevention

Both cigarette smoking and alcohol drinking are well-established risk factors for esophageal squamous cell carcinoma (ESCC), and the relationship of dose to cancer risk has already been described. Furthermore, the synergistic effect of these two factors has been reported. Our case–control study revealed the odds ratio of ESCC to be 50.1 for those who were both heavy smokers and heavy drinkers in comparison to people who neither drank nor smoked. In patients with ESCC, head and neck cancers as well as dysplastic lesions are frequently observed. Heavy smoking and heavy drinking are closely related to such multicentric carcinogenesis events in the upper aerodigestive tract (UADT), including the esophagus and head andneck region. Polymorphisms in acetaldehyde dehydrogenase 2 (ALDH2) are reported to be a key event in deciding individual susceptibility to UADT cancer. Patients with inactive ALDH2, in whom facial flushing is usually observed after the drinking of alcohol, are at high risk for ESCC as well as multiple UADT cancers. For the early detection of the disease, effective follow up using endoscopy with Lugol staining or narrow band imaging endoscopy is strongly recommended for high-risk populations, such as smokers, heavy drinkers, people with experience of flushing after the drinking of alcohol, and patients with UADT cancer.

Perturbation of transforming growth factor (TGF)-ß1 association with latent TGF-β binding protein yields inflammation and tumors

Transforming growth factor-β (TGF-β) activity is controlled at many levels including the conversion of the latent secreted form to its active state. TGF-β is often released as part of an inactive tripartite complex consisting of TGF-β, the TGF-β propeptide, and a molecule of latent TGF-β binding protein (LTBP). The interaction of TGF-β and its cleaved propeptide renders the growth factor latent, and the liberation of TGF-β from this state is crucial for signaling. To examine the contribution of LTBP to TGF-β function, we generated mice in which the cysteines that link the propeptide to LTBP were mutated to serines, thereby blocking covalent association. Tgfb1C33S/C33S mice had multiorgan inflammation, lack of skin Langerhans cells (LC), and a shortened lifespan, consistent with decreased TGF-β1 levels. However, the inflammatory response and decreased lifespan were not as severe as observed with Tgfb1−/− animals. Tgfb1C33S/C33S mice exhibited decreased levels of active TGF-β1, decreased TGF-β signaling, and tumors of the stomach, rectum, and anus. These data suggest that the association of LTBP with the latent TGF-β complex is important for proper TGF-β1 function and that Tgfb1C33S/C33S mice are hypomorphs for active TGF-β1. Moreover, although mechanisms exist to activate latent TGF-β1 in the absence of LTBP, these mechanisms are not as efficient as those that use the latent complex containing LTBP.

Clinical significance of Caveolin-1, Caveolin-2 and HER2/neu mRNA expression in human breast cancer.

Caveolin-1 and -2 (CAV1, CAV2) are closely linked genes localised to the fragile region of 7q31 (FRA7G), and loss of heterozygosity involving this region has been reported in breast cancer. Several studies have suggested that CAV1 is a negative regulator of HER2/neu signal transduction in vitro. However, the clinical significance of CAV1 in breast cancer has not yet been clarified. We examined quantitatively the mRNA levels of CAV1, CAV2 and HER2/neu in 162 cases of breast cancer using real-time PCR. Caveolin-1 and -2 protein expression was also examined by Western blotting and immunohistochemistry. We then evaluated for correlations between CAV1, CAV2 and HER2/neu gene expression and clinicopathologic factors in the 162 breast cancer cases. Results showed higher HER2/neu mRMA levels and lower CAV1 and CAV2 mRMA levels in breast cancer tissues than in corresponding normal tissues (P<0.001). Caveolin-1 and -2 protein expression levels were also suppressed in cancer tissues compared to normal tissues by Western blotting. Immunohistochemistry revealed that CAV1 and CAV2 proteins were abundantly expressed in mammary gland myoepithelial cells, but only weakly in ductalepithelial cells. Reduced CAV1 mRNA level was significantly associated with increasing tumour size (P=0.041), and negative oestrogen receptor status (P=0.021). There was also a significant association between low CAV2 mRNA level and negative progesterone receptor status (P=0.013), and between high HER2/neu mRNA level and negative hormonal receptor status (ER, P=0.029, PgR, P=0.019). While there was no relationship between HER2/neu and CAV1 mRNA levels, a significant association between CAV1 and CAV2 mRNA levels was observed (P<0.001). Our results indicated that CAV1 suppression correlated closely with that of CAV2 in breast cancer, that CAV1 level was inversely correlated with tumour size, and that CAV1 and CAV2 levels were correlated with hormonal receptor status. Therefore, CAV1 and CAV2 play an important role in tumour progression in breast cancer patients.

MAL gene expression in esophageal cancer suppresses motility, invasion and tumorigenicity and enhances apoptosis through the Fas pathway

We isolated the MAL (T-lymphocyte maturation associated protein) gene from differentially expressed products of esophageal epithelium relative to esophageal carcinoma tissues. The Mal protein has been demonstrated as being a component of the protein machinery for apical transport in epithelial polarized cells. In this study, we describe the reduced expression of MAL in all 39 cases of esophageal carcinoma tested and 60 other human carcinomas. MAL gene transcription was induced in three out of 13 esophageal carcinoma cell lines by treatment with the demethylating agent 5-aza-2′-deoxycytidine (DAC), and in nine additional cell lines by simultaneous treatment with trichostatin A, an inhibitor of deacetylation, and DAC. We established a stable MAL gene transfectant whose expression was regulated by subcutaneous doxycycline injection in nude mice. Tumor growth was suppressed in cells expressing TE3-MAL compared with TE3 parent cells or cells not expressing TE3-MAL with doxycycline injection (20 μg/body) (P<0.01). Additionally, the TE3-MAL transfectant cells exhibited decreased cellular motility, a G1/S transition block and increased levels of apoptosis, concomitant with increased expression of Fas receptor in vitro. The apoptotic staining in MAL-expressing tumors was confirmed by TUNEL assay. Therefore, we conclude that expression of MAL was frequently decreased or diminished in gastrointestinal tract cancers, and that Mal expression confers reduced tumorigenicity in vivo to tumor TE3 cells through the induction of apoptosis via the Fas signaling pathway.

Activin A Causes Cancer Cell Aggressiveness in Esophageal Squamous Cell Carcinoma Cells

Expression of activin A is associated with lymph node metastasis and clinical stage in esophageal cancer. To clarify the aggressive behavior of tumors with high activin A expression, we used the β subunit of activin A to establish stable activin βA (Act-βA)-transfected carcinoma cells in two human esophageal carcinoma cell lines, KYSE110 and KYSE140. The biological behavior of these cells was compared with that in mock-transfected cells from the same cell lines. We focused our attention on cell growth and tumorigenesis, and proliferation and apoptosis. Both Act-βA–transfected carcinoma cell lines showed a higher growth rate than the mock-transfected carcinoma cells. In an in vitro invasion assay and a xenograft analysis, the Act-βA–transfected carcinoma cells showed far higher proliferation in vitro and a higher potency for tumorigenesis in vivo, respectively. Moreover, in an analysis of apoptosis via Fas stimulation, the Act-βA–transfected carcinoma cells showed a higher tolerance to apoptosis compared with the mock-transfected carcinoma cells. Moreover, anti–activin-neutralizing antibody–treated squamous cell cancer cell lines inhibited their migration. Collectively, these data indicate that continuous high expression of activin A in esophageal carcinoma cells is not related to tumor suppression, but rather to tumor progression in vitro and in vivo. The inhibition of activin might be one of the methods to attenuate tumor aggressiveness.

Biological mechanism and clinical effect of protein-bound polysaccharide K (KRESTIN®): Review of development and future perspectives

The mechanism of action of protein-bound polysaccharide K (PSK; KRESTIN®) involves the following actions: (1) recovery from immunosuppression induced by humoral factors such as transforming growth factor (TGF)-β or as a result of surgery and chemotherapy; (2) activation of antitumor immune responses including maturation of dendritic cells, correction of Th1/Th2 imbalance, and promotion of interleukin-15 production by monocytes; and (3) enhancement of the antitumor effect of chemotherapy by induction of apoptosis and inhibition of metastasis through direct actions on tumor cells. The clinical effectiveness of PSK has been demonstrated for various cancers. In patients with gastric or colorectal cancer, combined use of PSK with postoperative adjuvant chemotherapy prolongs survival, and this effect has been confirmed in multiple meta-analyses. For small-cell lung carcinoma, PSK in conjunction with chemotherapy prolongs the remission period. In addition, PSK has been shown to be effective against various other cancers, reduce the adverse effects of chemotherapy, and improve quality of life. Future studies should examine the effects of PSK under different host immune conditions and tumor properties, elucidate the mechanism of action exhibited in each situation, and identify biomarkers.

N-cadherin is regulated by activin A and associated with tumor aggressiveness in esophageal carcinoma

Purpose: Activin A is a member of the transforming growth factor β superfamily and plays an important role in the differentiation of embryonic stem cells. We have reported previously that the expression of activin A is associated with lymph node metastasis in esophageal cancer, and our purpose in the current work is to clarify the molecular mechanism of the aggressive behavior of tumors that have high activin A expression. Experimental Design: We have compared the gene expression profiles of human esophageal carcinoma cell lines that were stably transfected with activin βA, which is a subunit of activin A, with those of control human esophageal carcinoma cell lines, using a cDNA microarray. Results: We found that the expression level of neuronal cadherin (N-cadherin) was higher in the transfectants than in the control cells. N-cadherin was located on the cell surface of the transfectants, irrespective of the expression of epithelial cadherin (E-cadherin), and the expression of N-cadherin mRNA was significantly associated with that of activin βA mRNA in clinical samples of esophageal carcinoma (n = 51; r = 0.855). A clinicopathologic analysis suggested that expression of N-cadherin mRNA was associated with the depth of tumor wall invasion, and a group of patients with high expression of N-cadherin mRNA showed a significantly poorer prognosis than a group of patients with low N-cadherin expression (P = 0.046). Conclusions: These results indicate that activin A might mediate the expression of N-cadherin and that this may be associated with depth of invasion and poor prognosis.

High expression of BUBR1 is one of the factors for inducing DNA aneuploidy and progression in gastric cancer

(Cancer Sci 2010; 101: 639–645)

Copy-neutral loss of heterozygosity at the p53 locus in carcinogenesis of esophageal squamous cell carcinomas associated with p53 mutations

Purpose: LOH at the p53 locus has been reported to be associated with esophageal squamous cell carcinogenesis. The aim of this study is to identify potential mechanisms resulting in LOH around the p53 locus in its carcinogenesis. Experimental Design: We investigated 10 esophageal cancer cell lines and 91 surgically resected specimens, examining them for LOH at the p53 locus on chromosome 17. We examined the p53 gene by using microsatellite analysis, comparative genomic hybridization (CGH), FISH, and single-nucleotide polymorphism–CGH (SNP–CGH). Results: In an analysis of specimens by microsatellite markers, a close positive correlation was found between p53 mutations and LOH at the p53 locus (P < 0.01). Although four cell lines were found to be homozygous for p53 mutations, LOH at the p53 locus was not detected by CGH. Among two p53 mutant cancer cell lines and five p53 mutant/LOH cancer specimens analyzed by FISH, both the cell lines and four of the specimens exhibited no obvious copy number loss at the p53 locus. SNP–CGH analysis, which allows both determination of DNA copy number and detection of copy-neutral LOH, showed that LOHs without copy number change were caused by whole or large chromosomal alteration. Conclusions: LOH without copy number change at the p53 locus was observed in p53 mutant esophageal squamous cell carcinomas. Our data suggest that copy-neutral LOH occurring as a result of chromosomal instability might be the major mechanism for inactivation of the intact allele in esophageal squamous cell carcinogenesis associated with p53 mutation. Clin Cancer Res; 17(7); 1731–40. ©2011 AACR.

Coexpression of Matrix Metalloproteinase-7 (MMP-7) and Epidermal Growth Factor (EGF) Receptor in Colorectal Cancer An EGF Receptor Tyrosine Kinase Inhibitor Is Effective against MMP-7–Expressing Cancer Cells

Purpose: Matrix metalloproteinase-7 (MMP-7) plays an important role in carcinoma invasion and metastasis of cancer. Recent studies focus on diverse roles of MMP-7, other than as a protease, during cancer progression. MMP-7 activates the epidermal growth factor (EGF) receptor by releasing an EGF ligand, tumor growth factor (TGF)-α. Experimental Design: We examined expression of MMP-7 and EGF receptor in an immunohistochemical study of 40 colorectal cancer (CRC) cases. To determine the relationship between the EGF receptor and MMP-7, with a potential curative application, we compared the antitumor activity of the EGF receptor tyrosine kinase inhibitor (gefitinib) between MMP-7 transfectant, KYSE150 and HT29, and control cells. Results: We found a statistically significant correlation (P = 0.04) between MMP-7 and activated (phosphorylated) EGF receptor expression, both being positive in six (15%) cases. Gefitinib reduced the cell number ratio more for MMP-7 transfectant than mock cells, and the proportion of apoptotic cells was 1.5 times higher in MMP-7 transfectant than mock cells by annexin/propidium iodide staining. This was mediated by activation of a TGF-β signal as confirmed by the abundant expression of TGF-β protein, the cytoplasmic to nuclear translocation of Smad4 protein by the administration of gefitinib, and the quantitative assay of the plasminogen activator inhibitor-1 promoter/luciferase construction. Conclusions: We propose that there are some cancers with up-regulated MMP-7 expression that leads to the activation of apoptotic activity of TGF-β, which is susceptible to treatment with EGF receptor tyrosine kinase inhibitor.