Differential epithelium DNA damage response to ATM and DNA-PK pathway inhibition in human prostate tissue culture

The ability of cells to respond and repair DNA damage is fundamental for the maintenance of genomic integrity. Ex vivo culturing of surgery-derived human tissues has provided a significant advancement to assess DNA damage response (DDR) in the context of normal cytoarchitecture in a non-proliferating tissue. Here, we assess the dependency of prostate epithelium DDR on ATM and DNA-PKcs, the major kinases responsible for damage detection and repair by nonhomologous end-joining (NHEJ), respectively. DNA damage was caused by ionizing radiation (IR) and cytotoxic drugs, cultured tissues were treated with ATM and DNA-PK inhibitors, and DDR was assessed by phosphorylation of ATM and its targets H2AX and KAP1, a heterochromatin binding protein. Phosphorylation of H2AX and KAP1 was fast, transient and fully dependent on ATM, but these responses were moderate in luminal cells. In contrast, DNA-PKcs was phosphorylated in both luminal and basal cells, suggesting that DNA-PK-dependent repair was also activated in the luminal cells despite the diminished H2AX and KAP1 responses. These results indicate that prostate epithelial cell types have constitutively dissimilar responses to DNA damage. We correlate the altered damage response to the differential chromatin state of the cells. These findings are relevant in understanding how the epithelium senses and responds to DNA damage.

Feasibility of tri-weekly docetaxel-based chemotherapy for elderly patients (age 75 and older) with castration-resistant prostate cancer

OBJECTIVES

To evaluate the efficacy and safety of docetaxel-based chemotherapy for elderly metastatic castration-resistant prostate cancer (CRPC) patients aged 75 or higher.

METHODS

Twenty CRPC patients aged 75 or higher (older group) and 31 CRPC patients younger than 75 years (younger group) were treated by a regimen of docetaxel (70 mg/m(2)) once every 3 weeks. Adjustment for docetaxel dosage and period per cycle was subject to investigator's judgment.

RESULTS

The median relative dose intensity of both groups was 0.84, while the median dose intensity and the number of treatment cycles of the younger and older groups were 14.6 versus 12.3 mg/m(2)/week (p = 0.021), and 9 versus 8 cycles (p = 0.15), respectively. In the older group, PSA response rate was 50%, median time to biochemical progression was 7.5 months, and median survival time was 15.5 months, without any significant difference compared to those of the younger group. No significant difference in the incidence of grade 3-4 adverse events was noted between both groups. All these parameters for efficacy are comparable to those reported for tri-weekly docetaxel regimen.

CONCLUSIONS

Tri-weekly treatment by docetaxel (70 mg/m(2)) with proper adjustment might contribute to maintaining efficacy and safety of the treatment for elderly CRPC patients.

Alterations in nucleolar structure and gene expression programs in prostatic neoplasia are driven by the MYC oncogene

Increased nucleolar size and number are hallmark features of many cancers. In prostate cancer, nucleolar enlargement and increased numbers are some of the earliest morphological changes associated with development of premalignant prostate intraepithelial neoplasia (PIN) lesions and invasive adenocarcinomas. However, the molecular mechanisms that induce nucleolar alterations in PIN and prostate cancer remain largely unknown. We verify that activation of the MYC oncogene, which is overexpressed in most human PIN and prostatic adenocarcinomas, leads to formation of enlarged nucleoli and increased nucleolar number in prostate luminal epithelial cells in vivo. In prostate cancer cells in vitro, MYC expression is needed for maintenance of nucleolar number, and a nucleolar program of gene expression. To begin to decipher the functional relevance of this transcriptional program in prostate cancer, we examined FBL (encoding fibrillarin), a MYC target gene, and report that fibrillarin is required for proliferation, clonogenic survival, and proper ribosomal RNA accumulation/processing in human prostate cancer cells. Further, fibrillarin is overexpressed in PIN lesions induced by MYC overexpression in the mouse prostate, and in human clinical prostate adenocarcinoma and PIN lesions, where its expression correlates with MYC levels. These studies demonstrate that overexpression of the MYC oncogene increases nucleolar number and size and a nucleolar program of gene expression in prostate epithelial cells, thus providing a molecular mechanism responsible for hallmark nucleolar alterations in prostatic neoplasia.

Abstract 263: MYC enforces overexpression of EZH2 in early prostatic neoplasia via transcriptional and posttranscriptional mechanisms

EZH2 is part of the PRC2 polycomb repressive complex that is overexpressed in multiple cancer types and has been implicated in prostate cancer initiation and progression. Here we identify EZH2 as a target of the MYC oncogene in prostate cancer and show that MYC coordinately regulates EZH2 through transcriptional and post-transcriptional means. Although prior studies in prostate cancer revealed a number of possible mechanisms of EZH2 upregulation, these changes cannot account for the overexpression of EZH2 in many primary prostate cancers, nor in most cases of high grade PIN. We report that upregulation of MYC in the mouse prostate results in overexpression of EZH2 mRNA and protein which coincides with reductions in miR-26a and miR-26b, known regulators of EZH2 in some non-prostate cell types, albeit not in others. Further, in human prostate cancer cells, MYC negatively regulates miR-26a and miR-26b via direct binding to their parental Pol II gene promoters, and forced overexpression of miR-26a and miR-26b in prostate cancer cells results in decreased EZH2 levels and suppressed proliferation. In human clinical samples, miR-26a and miR-26b are downregulated in most prostate cancers. In a novel mechanism of EZH2 mRNA upregulation, we find that MYC binds directly to and activates the transcription of the EZH2 promoter. These results link two major pathways in prostate cancer by providing two additional and complementary MYC-regulated mechanisms by which EZH2 upregulation occurs and is enforced during prostatic carcinogenesis. Further, the results implicate EZH2-driven mechanisms by which MYC may stimulate prostate tumor initiation and disease progression.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 263. doi:10.1158/1538-7445.AM2011-263

Effect of Kampo medicine Juzen-taiho-to on adverse events induced by cetuximab

396

Background: Cetuximab is now considered a standard treatment for advanced or unresectable colorectal cancer, unfortunately patients suffer a skin reaction as the main indication of the toxicity of cetuximab. It is recently reported that Kampo medicine (Goshajinkigan) is considered to be an effective agent for the neuropathy of oxaliplatin. Kampo medicine “Juzen-taiho-to” (TJ-48, Tsumura CO. Ltd.), which consists of 10 component herbs, is known as a tonic agent which improves the general systemic condition of cancer patients by reducing the adverse effects of chemotherapy, radiation therapy, and surgical treatment and to inhibit metastases. The aim of this study was to clarify the efficacy of TJ-48 for adverse events associated with cetuximab therapy.

Methods: From 2009, cetuximab was administered initially at a dose of 400 mg/m2 followed by weekly infusions at 250 mg/m2 to 20 patients with non-resectable or recurrent colorectal cancer. Eighteen patients received oral administration of 7.5 g/day of TJ-48 (TJ-48 group) every day in the first course and 7 patients did not receive TJ-48 (Control group). Adverse events were evaluated for every course according to CTCAE version 3.0.

Results: There was no statistically significant difference between the two groups based on any of patient characteristics. No patients complained of persistent Grade 3 infusion reaction. The percentage of Grade 2 or more skin reactions in each course tended to be lower in the TJ-48 group compared with the Control group (TJ-48 group 34% vs control group 57%). Incidence of Grade 2 anorexia in the TJ-48 group was significantly lower than in the Control group (TJ-48 group 34% vs control group 71%, p=0.03). There were no differences regarding tumor response between the two groups.

Conclusions: TJ-48 is useful to prevent anorexia in non-resectable or recurrent colorectal cancer patients treated with cetuximab regimen.

[Table: see text]

The role of UGT1A1 polymorphisms (*28 and *6) in Japanese cancer patients

570

Background: Combination protocol using FU-LV with irinotecan (FOLFIRI) is currently regarded as standard first-line therapy in advanced colorectal cancer (CRC). Although irinotecan prolongs survival, it causes severe diarrhea and neutropenia. Recent pharmacogenetic studies on irinotecan have revealed significant associations of UDP-glucuronosyltransferase 1A1 (UGT1A1) polymorphisms *28 and *6, the latter being specifically detected in East Asians resulting in severe toxicity. It is necessary that the dose-finding trial that decided the optimal dose according to the gene polymorphism to draw out the maximum therapeutic effect while evading the side effect. Here we present the result of prospective trial of the safety about FOLFIRI therapy according to each gene type of UGT1A1 for Japanese patients with advanced CRC.

Methods: From 2008, 250 Japanese patients in TOKUSHIMA University were enrolled in this study. Homo group (*6/*6 and *28/*28 or a both hetero types), hetero group (It was *28 and either *6 was hetero type), and wild group (*28 and *6 were wild types) were defined. On the 23 patients with advanced CRC treated with FOLFIRI after standard chemotherapy, wild and homo groups were administered 150mg/m2 irinotecan, and homo group was 100mg/m2.

Results: On the 23 patients, the genotypes of UGT1A1 *28 were homozygous in 1 (0.5%) and heterozygous in 5 (28%), *6 were homozygous in 0 and heterozygous in 6 (26%). In *6 heterozygous patients, severe toxicities (grade 3 or more) were found (33%), but in *28 heterozygous patients were not (0%). There was no decrease of irinotecan doses in each group. In Japanese people, UGT1A1 *6 polymorphisms were higher than *28 (*6 homo 3%, hetero 27% vs *28 homo 0.5%, hetero 13%).

Conclusions: When the dosage of irinotecan is decided, it is necessary to consider the UGT1A1 *6 heterozygous in Japanese cancer patients.

[Table: see text]

A randomized phase II trial of chemoradiotherapy with oral fluoropyrimidine inhibitory for dihydropyrimidine dehydrogenase for low rectal cancer: An interim report

524

Background: Preoperative chemoradiotherapy (CRT) has been widely used to improve local control of disease and to preserve anal sphincter in the treatment of rectal cancer. However, the response to CRT differs among individual tumors. In ASCO 2008 Gastrointestinal Cancers Symposium, we reported that the patients with up-regulation of 17 genes were suggested to be good responder of CRT. Our purpose of this study was to evaluate the toxicity and efficacy of CRT using UFT versus S-1 and explore biomarkers for response in patients with locally advanced rectal cancer.

Methods: Fifty patients who received preoperative CRT (40Gy radiotherapy) were randomly assigned to either UFT or S-1. UFT and S-1 were administered during the radiotherapy course. S-1 was a novel oral fluoropyrimidine inhibitory for dihydropyrimidine dehydrogenase and had potent radiosensitizing property. Biopsy specimens were obtained from rectal cancer before preoperative CRT and were analyzed by focused DNA microarray (132 genes). To pick up the predictive factors, the 132 genes were selected in the view of sensitivity of 5FU. Response to CRT was determined by RECIST and histopathologic examination of surgically resected specimens and classified as responders (CR, PR and grade 2, 3) or nonresponders (SD, PD and grade 0, 1).

Results: UFT group (n=25) and S-1 group (n=25) were enrolled. Response rate (grade 2 or 3) to CRT determined by histopathologic examination of surgically resected specimens was 58% in the UFT group and was 75% in the S-1 group. Response rate evaluated by RECIST criteria was 62% in the UFT group and was 77% in the S-1 group. National Cancer Institute Common Toxicity Criteria grade 2 or 3 toxicity was observed in 8% of the patients in the UFT group and 23% of patients in the S-1 group. Grade 2 or 3 toxicity in the UFT group was neutropenia and was diarrhea, neutropenia and dermatitis in the S-1 group. In ASCO 2010, we will report each candidate biomarker genes for response to CRT in the UFT and S-1 group.

Conclusions: The results have suggested that CRT using UFT or S-1 is feasible and effective for patients with locally advanced rectal cancer.

[Table: see text]

Role of thrombospondin 1 (THBS1) expression in peritoneal metastasis of gastric cancer treated with taxanes

57

Background: To clarify the utility of taxanes and to pick up the prognostic factors in the treatment with 5FU- based chemotherapy for peritoneal metastasis of gastric cancer.

Methods: Responder analysis: 18 patients with peritoneal metastasis of gastric cancer were enrolled in phase I study. The regimen consists of S-1 (80-120 mg) for 14 days and intraperitoneal infusion of PTX (dose escalation: 40 - 100 mg/m2) at day 1 and 14, which was repeated 2 cycles. To pick up the predictive factors, the 137 genes, which were selected in the viewpoint of sensitivity of 5FU, CPT11 and taxanes, were analyzed using focused DNA microarray for the 12 patients. Role of THBS1 expression: THBS1 expressions were evaluated in immunohistochemical (IHC) staining of surgical specimens of 59 patients with peritoneal metastasis of gastric cancer who were administered 5FU-based chemotherapy. THBS1 positive was defined > 30% of the population stained moderate to strong.

Results: Responder analysis: Expressions of THBS1 gene of the 6 patients who had clinical benefits (2: partial response, 2: positive adenocarcinoma cells in peritoneal cytology became negative, 2: remarkable decrease of ascites) were more than 2 folds higher than those of no responders. THBS1 expression was confirmed in 5 (83.3%) using IHC staining, who had significantly higher survival rate compared with that of the negative. Role of THBS1 expression: 17 patients (28.8%) was THBS1 positive and had significantly better prognosis compared with negative patients (1year survival: 64.7% vs 34.7%). 38 patients treated with regimes including taxanes revealed a tendency of improved overall survival rates (p=0.05). Overall survival of 15 patients with THBS1 positive administered taxanes was significantly higher than that of the negative patients. (1 year survival: 66.7% vs 42.4%)

Conclusions: PTX could improve the survival of peritoneal metastasis of gastric cancer. THBS1 is a prognostic factor especially in the patients treated with taxanes, which leads to tailor-made therapy.

[Table: see text]

MEPE Activated by Furin Promotes Pulpal Cell Adhesion

Matrix extracellular phosphoglycoprotein (MEPE) is predominantly expressed in osteoblasts, osteocytes, and odontoblasts and plays key biological roles in bone and dentin metabolism. Post-translational modifications are essential for its activation. This study tested the hypothesis that MEPE is activated through proteolytic processing by furin in dental pulp. MEPE was present in three sizes, 1 full-length and 2 cleaved fragments; the cleavage site was 146R↓147. The proprotein convertase family, particularly furin, was a candidate enzyme. Introducing a substitution at the cleavage site inhibited hydrolysis, but there was no cleavage of MEPE expressed in furin-deficient LoVo cells. Therefore, furin is a strong candidate for the proteolytic cleavage of MEPE. The C-terminal cleavage product promoted cell adhesion via its RGD motif. These results indicate that proteolytic processing by furin may activate MEPE during its secretion from odontoblasts and may play important roles in dentinogenesis and pulpal homeostasis. Abbreviations: MEPE, matrix extracellular phosphoglycoprotein; PTM, post-translational modifications; OLC, odontoblast-lineage cells.

Effect of triple costimulation blockade on islet allograft survival in sensitized mice

BACKGROUND

Islet allograft rejection in sensitized recipients is difficult to control by costimulation blockade using anti-CD154 and cytotoxic T-lymphocyte antigen-4 immunoglobulin (CTLA4Ig). Because leukocyte function antigen (LFA) 1 is highly expressed on memory T cells, adding an LFA-1 blockade may inhibit memory T-cell activities. We examined the effects on islet allograft survival of triple costimulation blockade in presensitized recipient mice.

METHODS

C57BL/6 mice were sensitized by transplantation under the kidney capsule or intraperitoneal injection of Balb/c islets. Four weeks after transplantation, sensitization was confirmed by flow-cytometric detection of alloreactive antibodies. Diabetes was induced by a single intravenous injection of streptozotocin. Recipients were transplanted with 200 Balb/c islets under the right kidney capsule. Graft function was assessed by daily blood glucose and body weight records. Transplanted animals were divided into 3 treatment groups: group 1, control antibody; group 2, anti-CD154 and CTLA-4 Ig double therapy; group 3, anti-CD154, CTLA4Ig, and anti-LFA-1 triple therapy. Injections were administered every second day from day -2 to day 8.

RESULTS

Naïve mice rejected islet allografts between days 7 and 29 (mean 16 +/- 6 d; n = 5), sensitized mice in group 1 between days 0 and 14 (mean 7 +/- 5 d; n = 8), in group 2 between days 4 and 16 (mean 8 +/- 4 d; n = 7), and in group 3 between days 4 and 26 (mean 11 +/- 7 d; n = 10).

CONCLUSION

Triple costimulation blockade with anti-CD154, CTLA4Ig, and anti-LFA-1 was not sufficient to improve islet allograft survival in sensitized recipients.

Prevalence of Salmonella, Yersinia and Campylobacter spp. in feral raccoons (Procyon lotor) and masked palm civets (Paguma larvata) in Japan

To estimate the public and animal health risk that alien species pose, the prevalence of Salmonella, Yersinia, and Campylobacter spp. in feral raccoons (Procyon lotor, n = 459) and masked palm civets (Paguma larvata, n = 153), which are abundant alien species in Japan, was investigated in urban and suburban areas of Japan. Salmonella enterica was detected from 29 samples [26 raccoons, 5.7%, 95% confidence interval (CI) 7.8–3.5%; three masked palm civets, 2.0%, 95% CI 4.2–0%]. Many of the isolates belonged to serovars that are commonly isolated from human gastroenteritis patients (e.g. S. Infantis, S. Typhimurium, and S. Thompson). The antimicrobial susceptibility test showed that 26.9 % of the isolates from raccoons were resistant to at least one antimicrobial agent, whereas none of the isolates from masked palm civets were resistant. Yersinia sp. was detected from 193 samples (177 raccoons, 38.6%, 95% CI 43.0–34.1%; 16 masked palm civets, 10.5%, 95% CI 15.3–5.6%). All virulent Yersinia strains belonged to Yersinia pseudotuberculosis, which was isolated from seven (1.5%, 95% CI 2.6–0.4%) raccoons and six (3.9%, 95% CI 7.0–0.8%) masked palm civets. According to the detection of virulence factors, all the Y. pseudotuberculosis isolates belonged to the Far Eastern systemic pathogenicity type. Campylobacter spp. was detected from 17 samples (six raccoons, 1.3%, 95% CI 2.3–0.3%; 11 masked palm civets, 7.2%, 95% CI 11.3–3.1%). Among these, three isolates from raccoons were identified as C. jejuni. These results showed that these pathogens can be transmitted by human activities, other wild animals, and the environment to feral raccoons and masked palm civets, and vice versa. As these animals have omnivorous behaviour and a wide range of habitats, they can play an important role in the transmission of the enteric pathogens.

Technique for a hybrid system of real-time transrectal ultrasound with preoperative magnetic resonance imaging in the guidance of targeted prostate biopsy

Diagnostic magnetic resonance imaging (MRI) for prostate has achieved increasingly higher levels of accuracy. Because real-time MR-guided targeted biopsy is still a complicated and expensive procedure, there is considerable interest in a technique of MR/transrectal ultrasound (TRUS) hybridized image-guided biopsy. However, because the 3-D shapes of the prostate at the time of image-acquisition at preoperative MRI are likely to be different from the intra-operative TRUS images, the precise registration of each 3-D volume data is critical. To reduce the potential errors in registration of TRUS with MRI, we introduce new procedural techniques in a rigid image fusion technique. First, preoperative MR images were obtained with a specifically-made plastic outer-frame, with exactly the same shape as the real TRUS probe, placed in the rectum, in order to simulate the deformation of the prostate caused by the absence or presence of a TRUS probe during the acquisition of MR or TRUS images. Second, instead of using a single plane of longitudinal image, we applied biplane TRUS images to be shown in parallel on a multiplanar display with corresponding reconstructed MRI, in order to register both horizontal and longitudinal images of the prostate simultaneously, thereby achieving improved 3-D anatomical matching.