Abstract 4662: Epigenetic conversion on p53 pathway in human cancer: The clinical potential of p53 mutation status as a predictive biomarker for drug sensitivity by epigenetic treatment

Background: DNA methylation plays a central role in epigenetic contribution to human cancer progression. We have mentioned actual epigenetic conversion on critical molecular pathways in human cancer (Mini-symposium on AACR 2012). Such genes included PGP9.5, NMDAR2B, DAPK, and Cyclin A1, which have been all demonstrated to be involved in apoptotic process on upstream or downstream of p53 pathway.

Materials and Methods: Epigenetic profiles of PGP9.5, NMDAR2B, and Cyclin A1 were examined in 163 primary gastric cancer by Q-MSP in combination with p53 mutation status (exon 4 to 8) by SSCP. Effects of epigenetic reversion by 5-aza-2’-deoxycytidine and trichostatin A, in combination with chemotherapeutic drug, CDDP, were assessed for apoptosis by flow cytometry and p53 trans-activation ability by luciferase analysis in gastric cancer cell lines with or without p53 mutation.

Results: (1) SSCP identified 44 mutations (27%) of p53 gene in primary gastric cancer. Mutation status of p53 gene was not of prognostic relevance. (2) We performed epigenetic profiles for PGP9.5, NMDAR2B, DAPK, and Cyclin A1. Methylation level is higher in primary tumors with p53 wild type than in those with p53 mutant in gastric cancer (PGP9.5>NMDAR2B>Cyclin A1>DAPK).(3) Importantly, super-high methylation level of PGP9.5, NMDAR2B, and cyclin A1 was exclusively found in primary tumors with no p53 mutation, and such cut-off TaqMeth values were 50, 163, and 133, respectively. (4) Super-high methylation was found in 14 for PGP9.5, 19 for NMDAR2B, and 8 in Cyclin A1, which are not always redundant. Super-high methylation may represent functional shut-down of expression in the individual genes. (5) In NUGC4 gastric cancer cell line, harboring wild type p53, epigenetic treatment remarkably augmented apoptosis by CDDP chemotherapy, concordant with p53 transcription activity. This finding suggested that epigenetic treatment could be additional options to classical chemotherapy more efficiently to kill cancer cells with wild type p53. (6) On the other hand, in KATO III cancer cell line, harboring null p53 (mutant), epigenetic treatment alone induced robust apoptosis, with no trans-activation of p53.

Conclusion: In GI cancers, several genes involved on the p53 pathway are functionally suppressed in expression by super-dense methylation of the promoter regions, and epigenetic reversion of p53 activity may be beneficial for killing cancer cells more efficiently, if p53 is not mutated. On the other hand, cancer cell with no p53 mutation is very sensitive by epigenetic treatments, and p53 status may predict sensitivity of cancer cells by chemotherapy in combination with epigenetic treatments.

Citation Format: Keishi Yamashita, Mina Waraya, Hiroshi Katoh, Akira Ooki, Hiroshi Kawamata, Kazunori Nakamura, Hiroshi Nishimiya, Akira Ema, David Sidransky, Masahiko Watanabe. Epigenetic conversion on p53 pathway in human cancer: The clinical potential of p53 mutation status as a predictive biomarker for drug sensitivity by epigenetic treatment. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4662. doi:10.1158/1538-7445.AM2013-4662

Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.

Perineural invasion and preoperative serum CA19-9 as predictors of survival in biliary tract cancer

BACKGROUND

Billiary tract cancer requires invasive surgical procedures for cure, and the risk factors related to patient prognosis remain controversial.

PATIENTS AND METHODS

Out of the 111 patients who underwent resection of extrahepatic biliary tract tumors from 1986 to 2010, the records for 88 with both ampullary and extrahepatic bile duct cancer, which included all information for evaluation of the clinicopathological factors, were employed in a multivariate analysis.

RESULTS

On univariate analysis, significant prognostic factors of poor survival unrelated to TNM factors were preoperative biliary drainage, high preoperative CA19-9 value, high preoperative CEA value, lymphatic invasion, perineural invasion, macroscopic growth pattern, histology, operative procedures (surgery), tumor persistence, high postoperative CA19-9 value, and postoperative chemotherapy. On multivariate analysis, perineural invasion (p=0.025) was the only prognostic factor independent of stage, for survival of patients with biliary tract cancer including ampullary cancer. When ampullary cancer was excluded, both perineural invasion and preoperative CA19-9 were the remaining prognostic factors independent of stage. The combination of both factors can very accurately identify long-term and short-term survivors of biliary tract cancer.

CONCLUSION

The present study, to our knowledge, for the first time shows that both perineural invasion and preoperative CA19-9 are important prognostic factors in biliary tract cancer, and this would be beneficial for clinical clarification of the optimal strategies for this type of cancer.

Cancer specific promoter CpG Islands hypermethylation of HOP homeobox (HOPX) gene and its potential tumor suppressive role in pancreatic carcinogenesis

Background

We have recently identified HOP hoemobox (HOPX) as a tumor suppressor gene candidate, characterized by tumor-specific promoter DNA hypermethylation in human cancers, and it can remarkably inhibit tumors’ aggressive phenotypes. In this current study, we for the first time examined methylation level of HOPX and tested the functional relevance in pancreatic cancer (PC).

Methods

Clinical features of HOPX promoter hypermethylation was investigated in 89 PC tissues, and immunohistochemistry was added. We also examined its functional relevance in phenotype assays such as soft agar, proliferation, invasion, and cell cycle analysis.

Results

PC tissues had HOPX gene hypermethylation as compared to the corresponding normal pancreas tissues, and its uniqueness was robust to discriminate tumor from normal tissues (AUC = 0.85, P < 0.0001). Unexpectedly, HOPX was increased in expression in tumor tissues, and immunohistochemistry revealed its predominant expression in the Langerhans islet cells, where HOPX was reduced in expression for PC cells with promoter hypermethylation. HOPX transfectants exhibited G1 arrest with subG1 accumulation, and inhibited tumor forming and invasive ability.

Conclusion

Defective expression of HOPX which is consistent with promoter DNA hypermethylation may explain aggressive phenotype of pancreatic cancer, and intense expression of HOPX in the Langerhans cells may in turn uniquely contribute to pancreatic carcinogenesis.

Abstract 4155: Comprehensive glucan profile exploration of mutated K-ras knockdown in colorectal cancer

(Background) In colorectal cancer (CRC), K-ras mutation is found in nearly 40% of the patients, and it is of prognostic significance (Onozato W et al, J Surg Oncol, 2010). Moreover, its knockdown in CRC cell lines with mutated K-ras gene results in robust reduction of ability of cell proliferation and anchorage independent growth (Shirasawa S, Science, 1993), both of which reflect metastatic ability. On the other hand, robust alterations of glycan structures have been reported in CRC promotion steps, accompanied by remarkable phenotypic changes, however there is no report that mentions the relationship of K-ras mutation and glycan change. (Materials and Methods) We examined glycan change of CRC cell lines (DLD1 and HCT116) somatically knocked out for K-ras gene by lectin array including 41 lectins to elucidate whether K-ras mutation-induced glycan changes play a critical role in CRC promotion. (Result) (1) In DLD1, we compared DLD1 wild type genotype cells (DLD1, DKS-5) with those that were knocked out for mutated K-ras gene (DKO-3, DKS-8), and the signals of MAL, MPA, UEA-I, and TJA-II were remarkably decreased in the knockdown cells. (2) In HCT116, we compared HCT116 wild type genotypic cells (HCT116, Hk2-10) with those that were knocked out for the mutated K-ras gene (Hke-3), and both MAL and MPA were remarkably declined. (3) In both cell lines, expression changes of glycans which can bind with MAL and MPA were consistent with the results of the lectin blotting, and both lectin signals were confirmed to be commonly altered by removing the mutated K-ras gene. (Conclusion) Mutated K-ras may be involved in critical phenotype change of CRC, accompanied by abnormal sialic acid recognition.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4155. doi:1538-7445.AM2012-4155

Therapeutic potential of PRL-3 targeting and clinical significance of PRL-3 genomic amplification in gastric cancer

Background

Phosphatase of regenerating liver-3 (PRL-3) has deserved attention as a crucial molecule in the multiple steps of metastasis. In the present study, we examined the mechanisms regulating PRL-3 expression, and assessed the clinical potential of PRL-3-targeted therapy in gastric cancer.

Methods

PRL-3 genomic amplification was analyzed using quantitative-polymerase chain reaction and/or fluorescence in situ hybridization in 77 primary gastric tumors. The anticancer activity of PRL-3 inhibitor (1-4-bromo-2-benzylidene rhodanine) treatment was evaluated against cancer cells with different genetic and expression status.

Results

PRL-3 genomic amplification was closely concordant with high level of its protein expression in cell lines, and was found in 20% (8/40) among human primary tumors with its expression, which were all stage III/IV disease (40%, 8/20), but in none (0/37) among those without expression. Additionally, PRL-3 genomic amplification was associated with metastatic lymph node status, leading to advanced stage and thereby poor outcomes in patients with lymph node metastasis (P = 0.021). PRL-3 small interfering RNA robustly repressed metastatic properties, including cell proliferation, invasion, and anchorage-independent colony formation. Although neither PRL-3 genomic amplification nor expression level was responsible for the sensitivity to PRL-3 inhibitor treatment, the inhibitor showed dose-dependent anticancer efficacy, and remarkably induced apoptosis on all the tested cell lines with PRL-3 expression.

Conclusions

We have for the first time, demonstrated that PRL-3 genomic amplification is one of the predominant mechanisms inducing its expression, especially in more advanced stage, and that PRL-3-targeted therapy may have a great potential against gastric cancer with its expression.

Successful blood pressure control with additive administration of eplerenone, an aldosterone receptor blocker, in a patient with bilateral renovascular hypertension treated with angioplasty

A 29-year-old woman with refractory hypertension who previously suffered from subarchnoid hemorrhage visited our facility. The diagnosis of renovascular hypertension due to fibromuscular dysplasia was made based on a high level of plasma renin activity (PRA) and aldosterone concentration (AC), and computed tomographic image of bilateral renal artery stenosis/obstruction. Angioplasty, which could be performed only to the left renal artery, failed to regain sufficient BP control. The addition of eplerenone, an aldosterone receptor blocker, to the conventional antihypertensive drugs successfully and safely lowered BP and preserved the renal function despite the persistence of high PRA and AC values.

Involvement of REG Ialpha protein in the regeneration of ductal epithelial cells in the minor salivary glands of patients with Sjögren's syndrome

The regenerating gene (Reg) was originally isolated from regenerating rat pancreatic islets and revealed recently to constitute a multi-gene family in humans. REG Ialpha protein is known to be overexpressed not only in various human inflammatory diseases but also in various experimental models of inflammation in animal tissues. However, its involvement in pathophysiology of the minor salivary gland (MSG) is not clear. We investigated REG Ialpha expression in the MSG of patients with primary Sjögren's syndrome (SS) and assessed its role in ductal epithelial cell proliferation in such tissues. Lip biopsy specimens were obtained from 40 patients with primary SS and examined using immunohistochemistry for REG Ialpha protein, Ki67 and single-strand DNA (ssDNA). The relationships among clinicopathological factors and expression of REG Ialpha protein, Ki67 and ssDNA in the MSG were then analysed. REG Ialpha protein was expressed rarely in ductal epithelial cells of the normal MSG but was apparently overexpressed in those of patients with SS. The labelling indices for both Ki67 and ssDNA in the ductal cells of the MSGs were significantly higher in SS patients than in controls. Moreover, these labelling indices were significantly higher in REG Ialpha-positive than in negative SS patients. REG Ialpha protein may play a role in the regeneration of ductal epithelial cells in the MSGs of patients with SS.

A simple yet effective multipass reflector for vibrational excitation in molecular beams

The fraction of molecules that can be vibrationally excited is often the limiting factor in many infrared laser excitation experiments, in particular, when using weak absorption bands. Reported here is a simple multipass reflector designed to overcome that obstacle. Its enhancement in pumping efficiency is demonstrated in a crossed-beam scattering experiment on the Cl+CH2D2(v1 or v6=1) reactions. Compared to a double-pass arrangement, the effective laser fluence for excitation is also characterized.

Photodissociation of nitrous oxide starting from excited bending levels

The photodissociation dynamics of N2O in the wavelength region of 203-205 nm was studied by velocity map ion imaging. A speed resolution of 0.8% was obtained using standard projection imaging and subpixel centroiding calculations. To investigate N2O dissociation starting from the excited bending levels in the ground electronic state, a supersonic molecular beam and an effusive beam were used. The photoabsorption transition probability from the first excited bending level in the wavelength region of 203-205 nm was estimated to be seven times greater than that from the ground vibrational level.

A case of dermoid cyst of the ovary with malignant transformation complicated with small intestinal fistula formation

A 54-year-old woman complained of abdominal pain and watery diarrhea that had begun two days before admission. Physical examination revealed abdominal distention and tenderness throughout the abdomen, but there was no muscle guarding or rebound tenderness. The leukocyte count was 27.0 x 10(3)/microl, and CRP was 28.5 mg/dl. A plain film of the abdomen revealed the shadow of a huge gas-containing mass with an air-fluid level and a dilated small intestine with air-fluid level. CT showed a huge gas-containing cystic mass with fatty component and solid structure. Omental thickening was also noted. Emergency surgery was performed, and an enlarged left ovary that was adherent to the small intestine was removed. Microscopic examination revealed a squamous cell carcinoma in the dermoid cyst wall. The carcinoma had directly invaded the small intestine and a fistula between the cyst and the intestine was noted. Thickened omentum showed granulomatous inflammation in the fatty tissue, but no metastases were detected. The histopathological diagnosis was dermoid cyst with malignant transformation and invasion of the small intestine. Chemotherapy was performed, but the patient died of progression of peritoneal metastases 10 months after the operation.

A MEK inhibitor (U0126) markedly inhibits direct liver invasion of orthotopically inoculated human gallbladder cancer cells in nude mice

Primary cancer of the gallbladder is not unusual. Most cases of gallbladder cancer are found at an advanced stage, accompanied by the invasion to the liver, metastases to the lymph nodes and distant organs, and peritoneal dissemination. In this study, we first examined the effect of mitogen-activated protein kinase kinase (MEK) inhibitors on the production of matrix metalloproteinases (MMPs), urokinase-type plasminogen activator (uPA), and tissue inhibitors of metalloproteinases (TIMPs) in a human gallbladder cancer cell line, NOZ cells in vitro. MEK inhibitors (PD98059 and U0126) inhibited the production of MMP-2, MMP-9 and high MW uPA, and upregulated TIMPs (TIMP-1, TIMP-2 and TIMP-3). Subsequently, we examined the effect of U0126 on invasion and metastasis of orthotopically inoculated NOZ cells in nude mice. Direct liver invasion by cancer cells was detected in all of the mice in the control group, but in only one mouse in the U0126-treated group. Most of the primary tumors in the U0126-treated group expanded to the liver, but did not invade into the liver. Vessel invasion in the liver was evident in 4 out of 5 mice in the control group, but in only one mouse in the U0126-treated group. Lymph node metastases and peritoneal dissemination were recognized in all of the mice in both groups. All 5 mice in the U0126-treated group, and 4 out of 5 mice in the vehicle control group, had metastases in the lungs. The present results suggest that a MEK inhibitor, U0126, prolonged the survival of the mice with NOZ tumor by inhibiting direct liver invasion and vessel invasion of the cancer cells via down-regulation of the matrix degrading ability of the cancer cells.

Frequent downregulation of 14-3-3 sigma protein and hypermethylation of 14-3-3 sigma gene in salivary gland adenoid cystic carcinoma

14-3-3 sigma:, a target gene of the p53 tumour suppressor protein, has been shown to regulate the cell cycle at the G2/M checkpoint. Recent studies have demonstrated that 14-3-3 sigma is downregulated by hypermethylation of the CpG island in several types of cancer. In this study, we investigated the expression and methylation status of 14-3-3 sigma in human salivary gland adenoid cystic carcinoma (ACC) and mucoepidermoid carcinoma (MEC). Immunohistochemical analysis revealed that the positive expression rate of 14-3-3 sigma in ACC (one out of 14) was markedly lower than that in MEC (ten out of 10). Since most of the ACCs carried the wild-type p53 protein, downregulation of 14-3-3 sigma in ACC may not be due to the dysfunction of p53 pathway. Microdissection-methylation-specific PCR revealed that frequent hypermethylation of the 14-3-3 sigma gene was observed in ACC when compared to that in MEC. In cultured-ACC cells, we confirmed the downregulation of 14-3-3 sigma via hemimethylation of the gene by sequencing analysis after sodium bisulphite treatment. Furthermore, re-expression of 14-3-3 sigma in the ACC cells was induced by the treatment with DNA demethylating agent, 5-aza-2'-deoxycytidine. Irradiation apparently induced the enhanced expression of 14-3-3 sigma and G2/M arrest in normal salivary gland cells; however, in the ACC cells, neither induction of 14-3-3 sigma nor G2/M arrest was induced by irradiation. These results suggest that downregulation of 14-3-3 sigma might play critical roles in the neoplastic development and radiosensitivity of ACC.

TSC-22 (TGF-beta stimulated clone-22): a novel molecular target for differentiation-inducing therapy in salivary gland cancer

TSC-22 (Transforming growth factor-beta stimulated clone-22) was originally isolated as a TGF-beta-inducible gene in mouse osteoblastic cells. TSC-22 encodes a putative transcriptional regulator containing a leucine zipper-like structure. Several differentiation-inducing stimuli up-regulate the TSC-22 gene. Furthermore, TSC-22 acts as an effector that integrates multiple extracellular signals during embryogenesis of Drosophila and mouse. Separately, we identified TSC-22 cDNA as an anti-cancer drug (vesnarinone)-inducible gene in a human salivary gland cancer cell line, TYS. Vesnarinone is known to have a differentiation-inducing activity in several cell types. We showed that TSC-22 negatively regulated the growth of TYS cells, and that down-regulation of TSC-22 played a major role in the salivary gland tumorigenesis. Subsequently, we found that artificial overexpression of TSC-22 enhanced chemosensitivity and radiation-sensitivity by inducing apoptosis in TYS cells. Recently, we isolated TSC-22 genomic DNA and analyzed the transcriptional and post-transcriptional regulation of the TSC-22 gene. Then, we confirmed by the luciferase reporter assay that several differentiation-inducing stimuli directly activated the promoter region of TSC-22 gene. Now we are investigating the chemical compounds, which could enhance the transcription of the TSC-22 gene. Thus, because TSC-22 is a key molecule for differentiation of several cells, it can be used as a molecular target for cancer differentiation therapy in salivary gland cancer.

Rupture of a thoracic aortic aneurysm: a rare adverse reaction following systemic tissue plasminogen activator infusion

We present a patient with rupture of a thoracic aortic aneurysm occurring after systemic infusion of tissue plasminogen activator for the treatment of acute ischemic stroke, which was successfully treated with the placement of an endovascular stent-graft.