MHC class I loaded ligands from breast cancer cell lines: A potential HLA-I-typed antigen collection

To build a catalog of peptides presented by breast cancer cells, we undertook systematic MHC class I immunoprecipitation followed by elution of MHC class I-loaded peptides in breast cancer cells. We determined the sequence of 3196 MHC class I ligands representing 1921 proteins from a panel of 20 breast cancer cell lines. After removing duplicate peptides, i.e., the same peptide eluted from more than one cell line, the total number of unique peptides was 2740. Of the unique peptides eluted, more than 1750 had been previously identified, and of these, sixteen have been shown to be immunogenic. Importantly, half of these immunogenic peptides were shared between different breast cancer cell lines. MHC class I binding probability was used to plot the distribution of the eluted peptides in accordance with the binding score for each breast cancer cell line. We also determined that the tested breast cancer cells presented 89 mutation-containing peptides and peptides derived from aberrantly translated genes, 7 of which were shared between four or two different cell lines. Overall, the high throughput identification of MHC class I-loaded peptides is an effective strategy for systematic characterization of cancer peptides, and could be employed for design of multi-peptide anticancer vaccines.

SIGNIFICANCE

By employing proteomic analyses of eluted peptides from breast cancer cells, the current study has built an initial HLA-I-typed antigen collection for breast cancer research. It was also determined that immunogenic epitopes can be identified using established cell lines and that shared immunogenic peptides can be found in different cancer types such as breast cancer and leukemia. Importantly, out of 3196 eluted peptides that included duplicate peptides in different cells 89 peptides either contained mutation in their sequence or were derived from aberrant translation suggesting that mutation-containing epitopes are on the order of 2-3% in breast cancer cells. Finally, our results suggest that interfering with MHC class I function is one of the mechanisms of how tumor cells escape immune system attack.

Factors affecting the restaging accuracy of magnetic resonance imaging after preoperative chemoradiation in patients with rectal cancer

PURPOSES

We evaluated patient or tumor factors associated with the preoperative restaging accuracy of magnetic resonance imaging (MRI) for determining T and N stages as well as circumferential resection margin (CRM) involvement after chemoradiation (CRT) in patients with locally advanced rectal cancer.

METHODS

Seventy-seven patients with rectal cancer that were treated with preoperative CRT (50.4 Gy) followed by radical resection were included. Post-CRT MRI was performed approximately 4 weeks after preoperative CRT.

RESULTS

The median tumor distance from the anal verge was 6 cm, 48 (62%) of which were anterior and 29 (38%) posterior. The median tumor diameter was 3 cm. A stage-by-stage comparison showed that correct staging occurred in 62%, 43%, and 86% of patients for T staging, N staging, and CRM prediction, respectively. Shorter distance to the anal verge (<5 cm), smaller tumor diameter (<1 cm), and anterior tumor location were associated with incorrect T staging. There were no significant variables in terms of N staging accuracy. Shorter tumor distance and anterior tumor location were associated with incorrect CRM prediction.

CONCLUSIONS

Our findings suggest that specific tumor factors such as small, distal, or anterior rectal tumors are closely associated with the accuracy of MRI after preoperative CRT.

Prospective study of the effectiveness of percutaneous transhepatic photodynamic therapy for advanced bile duct cancer and the role of intraductal ultrasonography in response assessment

BACKGROUND AND STUDY AIMS

We evaluated the therapeutic effects of percutaneous transhepatic photodynamic therapy (PDT) in patients with advanced bile duct cancer. The utility of intraductal ultrasonography (IDUS) for the assessment of responses and for regular follow up after PDT was also examined.

METHODS

Percutaneous transhepatic biliary drainage (PTBD) was initiated before PDT. Following dilation and maturation of the PTBD tract, percutaneous PDT was performed. Intraluminal photoactivation was carried out using percutaneous cholangioscopy 2 days after intravenous application of a hematoporphyrin derivative. All patients were additionally provided with percutaneous bile duct drainage catheters after PDT. IDUS was conducted monthly to measure the thickness of the tumor mass before and after PDT.

RESULTS

24 patients with advanced cholangiocarcinomas (Bismuth IIIa, n = 4; IIIb, n = 10; IV, n = 10) were treated with PDT. At 3 months after PDT, the mean thickness of the tumor mass had decreased from 8.7 +/- 3.7 mm to 5.8 +/- 2.0 mm (P < 0.01). At 4 months after PDT, the thickness of the mass had increased to 7.0 +/- 3.7 mm. Quality of life indices improved dramatically and remained stable 1 month after PDT; the Karnofsky index increased from 39.1 +/- 11.36 to 58.2 +/- 22.72 points (P = 0.003). The 30-day mortality rate was 0 %, and the median survival time was 558 +/- 178.8 days (current range 62 - 810 days).

CONCLUSIONS

PDT using percutaneous cholangioscopy is safe and effective for advanced hilar cholangiocarcinoma, and seems to prolong survival. IDUS is useful for evaluating changes in the thickness of the tumor mass after PDT.

Invasive intraductal papillary mucinous tumor of the pancreas with simultaneous invasion of the stomach and duodenum

An 81-year-old woman was admitted with epigastric pain and weight loss. She had been diagnosed with an intraductal papillary mucosal tumor (IPMT) 7 years previously, but had refused surgery for religious reasons. Esophagogastroduodenoscopy revealed a nodular, elevated lesion that was discharging mucin into the duodenal bulb and posterior wall of the upper body of the stomach. Endoscopic ultrasonography, abdominal computed tomography, and endoscopic retrograde cholangiography were carried out, and a highly invasive IPMT with simultaneous invasion of the stomach and duodenum was diagnosed.

Scaffold development using selective laser sintering of polyetheretherketone-hydroxyapatite biocomposite blends

In tissue engineering (TE), temporary three-dimensional scaffolds are essential to guide cell proliferation and to maintain native phenotypes in regenerating biologic tissues or organs. To create the scaffolds, rapid prototyping (RP) techniques are emerging as fabrication techniques of choice as they are capable of overcoming many of the limitations encountered with conventional manual-based fabrication processes. In this research, RP fabrication of solvent free porous polymeric and composite scaffolds was investigated. Biomaterials such as polyetheretherketone (PEEK) and hydroxyapatite (HA) were experimentally processed on a commercial selective laser sintering (SLS) RP system. The SLS technique is highly advantageous as it provides good user control over the microstructures of created scaffolds by adjusting the SLS process parameters. Different weight percentage (wt%) compositions of physically mixed PEEK/HA powder blends were sintered to assess their suitability for SLS processing. Microstructural assessments of the scaffolds were conducted using electron microscopy. The results ascertained the potential of SLS-fabricated TE scaffolds.

Evaluation of developmental toxicity in rats exposed to the environmental estrogen bisphenol A during pregnancy

Bisphenol A (BPA) is an essential component of epoxy resins used in the lacquer lining of metal food cans, as a component of polycarbonates, and in dental sealants. The present study was conducted in an attempt to evaluate the adverse effects of the environmental estrogen BPA on initiation and maintenance of pregnancy and embryofetal development after maternal exposure during the entire period of pregnancy in Sprague-Dawley rats. The test chemical was administered by gavage to mated females from days 1 to 20 of gestation (sperm in varginal lavage = day 0) at dose levels of 0, 100, 300, and 1000 mg/kg. All females were subjected to caesarean section on day 21 of gestation and their fetuses were examined for external, visceral and skeletal abnormalities. In the 1000 mg/kg group, significant toxic effects including abnormal clinical signs, decreased maternal body weight and body weight gain, and reduced food consumption were observed in pregnant rats. An increase in pregnancy failure was also found in the successfully mated females. In addition, increased number of embryonal deaths, increased postimplantation loss, reduced litter size and fetal body weight, and decreased number of fetal ossification centers of several skeletal districts were seen. On the contrary, no significant changes induced by BPA were detected in the number of corpora lutea and implantation sites and by fetal morphological examinations. In the 300 mg/kg group, suppressed maternal body weight and body weight gain, decreased food intake and reduced body weight of male fetuses were seen. There were no adverse signs of either maternal toxicity or developmental toxicity in the 100 mg/kg group. It was concluded that BPA administration during the entire period of pregnancy in rats produced pregnancy failure, pre- and postimplantation loss, fetal developmental delay and severe maternal toxicity, but no embryo-fetal dysmorphogenesis at an oral exposure level of 1000 mg/kg.

Subacute toxicities and toxicokinetics of a new erectogenic, DA-8159, after single and 4-week repeated oral administration in dogs

The subacute toxicities and toxicokinetics of a new erectogenic, DA-8159, were evaluated after single (at the 1st day) and 4-week (at the 28th day) oral administration of the drug, in doses of 0 (to serve as a control), 12.5, 50 and 200 mg/kg/day, to male and female dogs (n=3 for male and female dogs for each dose). DA-8159 had an effect on the immune-related organs (or tissues), circulatory systems, liver, adrenal glands, ovaries and pancreas. The toxic dose was 200 mg/kg and no observed adverse effect level was less than 50 mg/kg for male and female dogs. There were no significant gender differences in the pharmacokinetic parameters of DA-8159 for each dose after both single and 4-week oral administration. The pharmacokinetic parameters of DA-8159 were dose-independent after single oral administration; the time to reach a peak plasma concentration (T(max)) and the dose-normalized area under the plasma concentration-time curve from time zero to 24 h in plasma (AUC(0-24 h)) were not significantly different among three doses. However, accumulation of DA-8159 after 4-week oral administration was considerable at toxic dose, 200 mg/kg/day. For example, after 4-week administration, the dose-normalized AUC(0-24 h) value at 200 mg/kg/day (4.71 and 15.3 microg h/ml) was significantly greater than that at 12.5 mg/kg/day. After 4-week oral administration, the dose-normalized C(max) and AUC(0-24 h) at 200 mg/kg/day were significantly higher and greater, respectively, than those after a single oral administration.

Role of corticosterone in ethyl carbamate-induced immunosuppression in female BALB/c mice

We have recently demonstrated that the antibody response to the T-cell-dependent antigen, sheep red blood cells (SRBCs), was suppressed by ethyl carbamate in female BALB/c mice. At the same doses, ethyl carbamate decreased in the numbers of splenic macrophages, B cells, total T cells, CD4(+) T cells and CD8(+) T cells. In addition, the serum level of corticosterone was increased dose-dependently. To investigate the possible role of corticosterone in ethyl carbamate-induced immunosuppression, the antibody response to SRBCs and the subpopulation changes of splenocytes and thymocytes were determined in naive, sham-operated and adrenalectomized (ADX) female BALB/c mice. When the mice were treated intraperitoneally with 400 mg/kg ethyl carbamate, the antibody response was significantly suppressed by ethyl carbamate in naive and sham-operated mice in accompanying the decrease in spleen and thymus weights and/or the increase in the level of serum corticosterone. Meanwhile, the antibody response was not suppressed by ethyl carbamate in the ADX mice. The splenic numbers of total cells, macrophages, B and T cells, and CD4(+) cells were decreased by ethyl carbamate in naive and sham-operated mice. Meanwhile, each cell number was comparable with control in the ADX mice. The flow cytometric analyses on thymocytes did not show obvious differences as seen in the spleen. Finally, when the ADX mice were treated intraperitoneally with 25 mg/kg corticosterone, the antibody response was significantly suppressed. Taken together, our present results suggested that corticosterone might be, at least partially, responsible for ethyl carbamate-induced immunosuppression in female BALB/c mice.

Immunotoxicity of ethyl carbamate in female BALB/c mice: role of esterase and cytochrome P450

Ethyl carbamate, a potent carcinogen, has been characterized to be metabolized by cytochrome P450 (P450) and esterase. It has recently been demonstrated that P450 may activate ethyl carbamate to immunotoxic metabolites. To investigate the role of esterase in ethyl carbamate-induced immunosuppression, mice were pretreated intraperitoneally with an esterase inhibitor, diazinon, at 20 mg/kg 30 min prior to the administration of ethyl carbamate intraperitoneally at 100 and 400 mg/kg for 7 consecutive days. Pretreatment with diazinon completely blocked the serum esterase activity. Histopathologically splenic and thymic atrophy was observed when mice were treated with ethyl carbamate, which was potentiated by the pretreatment with diazinon. In spleen, lymphocytes in the periarteriolar lymphoid sheath and the marginal zone appeared to be depleted in the white pulps. In thymus, ethyl carbamate caused a marked depletion of cells in cortex. The antibody response to sheep red blood cells (SRBCs) was more suppressed by ethyl carbamate in diazinon-pretreated groups than in corn oil-pretreated groups. These results suggest that the metabolism of ethyl carbamate by esterase may be an inactivation pathway in ethyl carbamate-induced immunosuppression. In addition, ethyl N-hydroxycarbamate, a P450 metabolite, suppressed the lymphoproliferative response induced by lipopolysaccharide and concanavalin A in splenocyte cultures. These results indicate that the metabolism of ethyl carbamate by P450 may be an activation pathway in immunosuppression by ethyl carbamate.

Role of metabolic activation by cytochrome P450 in thioacetamide-induced suppression of antibody response in male BALB/c mice

Effects of thioacetamide on antibody response to sheep red blood cells were investigated in male BALB/c mice. When mice were treated intraperitoneally with thioacetamide once, the antibody response was significantly suppressed at 200 mg/kg with hepatotoxicity. When mice were treated intraperitoneally with thioacetamide for 7 consecutive days, the antibody response was suppressed at 50 mg/kg without hepatotoxicity. To determine the possible role of metabolic activation by cytochrome P450 in thioacetamide-induced suppression of antibody response, mice were pretreated with phenobarbital intraperitoneally for 3 days, followed by intraperitoneal administration of 100 mg/kg of thioacetamide for 3 days. The elevated activities of serum aspartate aminotransferase and alanine aminotransferase by thioacetamide were potentiated by phenobarbital pretreatment. The suppression of antibody response by thioacetamide was potentiated by phenobarbital. In liver microsomes, the activities of P450 2B-specific enzymes were induced by phenobarbital. Our present results suggest that thioacetamide may require metabolic activation by P450 to its immunosuppressive form(s).

A case of lymphomatoid papulosis occurred simultaneously with Ki-1-positive anaplastic large cell lymphoma

Lymphomatoid papulosis (LyP) is a chronic self-healing skin eruption that is clinically benign but histologically mimics a malignant lymphoma. However, lymphomatoid papulosis with anaplastic large cell lymphoma responds poorly to medical treatments, including chemotherapies. We experienced a 60-year-old male patient with lymphomatoid papulosis occurred simultaneously with relapsed Ki-1-positive anaplastic large cell lymphoma who was treated with salvage chemotherapy but, unfortunately, failed to be rescued. We report it with a review of the literature.

Enhancing effects of captafol on the development of GST-P-positive liver cell foci in a medium-term bioassay, and protection by L-cysteine of the enhancement in rats

The modifying effects of captafol and protective effects of L-cysteine on the development of glutathione S-transferase placental form-positive (GST-P +) foci of the liver and expression of proliferating cell nuclear antigen (PCNA) in the kidney were investigated in a medium-term bioassay using D-galactosamine (DGA) in rats. Male 6-week-old F344 rats were initially given a single i.p. injection (200 mg/kg) of diethylnitrosamine (DEN) and after 2 weeks on basal diet, received two i.p. injections of DGA (300 mg/kg) at the ends of weeks 2 and 5, and were fed a diet supplemented with test chemicals for weeks 3-8. Animals in group 1 were given 1500 ppm captafol in the diet, while group 2 received 1500 ppm captafol in diet as well as 1500 ppm L-cysteine in drinking water, animals in control group being given basal diet alone. Positive results regarding increased numbers and areas of GST-P + liver cell foci were obtained in rats treated with captafol alone. On the other hand, significant reduction by L-cysteine in the areas of GST-P + liver cell foci initiated by DEN and promoted by captafol was observed. In addition, the PCNA-labelling indices of renal tubule cells were elevated in rats treated with captafol alone and significantly reduced in rats treated simultaneously with L-cysteine. The protocol used in the present study therefore allowed the in vivo determination of promoting effects of captafol and inhibitory influence of L-cysteine by analyzing GST-P + foci in the livers as marker lesions, within a relatively short period of 8 weeks. Thus, this bioassay protocol could have applicability as a new in vivo assay system for the screening of hepatic carcinogenic or anti-carcinogenic agents.

Reappraisal of eight representative carcinogenic and non-carcinogenic compounds in a new medium-term rat liver bioassay using D-galactosamine

The carcinogenic potential of eight different compounds was assayed in a new medium-term carcinogenicity bioassay using D-galactosamine (DGA) as a non-surgical method to induce regeneration in place of partial hepatectomy (PH). Male rats were initially given a single i.p. injection (200 mg/kg) of diethylnitrosamine (DEN) and after 2 weeks on basal diet, received two i.p. injections of DGA (300 mg/kg) at the end of weeks 2 and 5. They were treated with one of the test compounds aflatoxin B1, benzo[a]pyrene, diethylstilbestrol, urethane, sodium saccharin, bucetin, D-mannitol and sodium chloride in the diet or basal diet alone for weeks 3-8. Carcinogenic potential was assessed by comparing the numbers and areas per cm2 of glutathione S-transferase placental form-positive (GST-P+) foci in the livers of treated animals with those of the control animals given DEN/DGA alone. Positive estimations of carcinogenicity were obtained for the hepatocarcinogens aflatoxin B1, diethylstilbestrol or urethane, and for the non-liver carcinogen benzo[a]pyrene. Negative values were shown in rats treated with the non-carcinogens, D-mannitol and sodium chloride. The two other non-liver carcinogens sodium saccharin and bucetin, also did not exert positive effects in the system. The present data are consistent with findings in previous medium-term bioassays using PH. Our results thus confirm that the present bioassay protocol with repeated administration of DGA instead of PH may offer a new and sensitive non-invasive method to screen large numbers of environmental carcinogens.

Effects of ethyl carbamate and its metabolites on the antibody response in splenocyte cultures from female Balb/C mice

To investigate a possible role by cytochrome P450 (P450) in ethyl carbamate-induced immunosuppression, an attempt to assess the ability of ethyl carbamate, its metabolites produced by P450 (i.e., ethyl N-hydroxycarbamate and vinyl carbamate), and methyl carbamate to suppress the polyclonal antibody response induced by bacterial lipopolysaccharide was made in splenocyte cultures isolated from female Balb/C mice. The results showed that vinyl carbamate and ethyl N-hydroxycarbamate were more immunosuppressive compared to ethyl carbamate. A structurally related analogue, methyl carbamate, did not suppress the antibody response. These results indicate that metabolism of ethyl carbamate by P450 may produce more immunosuppressive metabolites as in ethyl carbamate-induced carcinogenicity. A pre-incubation study with phenobarbital-induced liver microsomes in the presence of NADPH-generating system showed that the antibody response was suppressed by ethyl carbamate when splenocytes were pre-incubated with ethyl carbamate and microsomes simultaneously. Moreover, the suppression was completely recovered by the addition of a P450 inhibitor, aminoacetonitrile, in the pre-incubation. Taken together, the present results indicate that metabolism of ethyl carbamate by P450 enzyme(s) may be an important pathway to cause immunosuppression.

Projection of forelimb nerve afferents to external cuneate nucleus of the rat as revealed by intraneural injection of a neurotoxic lectin, Ricinus communis agglutinin

This study seeks to extend the observations of previous studies of projection of primary afferent fibres from the forelimb nerves and muscles to the external cuneate nucleus (ECN) of mammals using a neurotoxic lectin, Ricinus communis agglutinin (RCA) to achieve chemical ganglionectomy of the dorsal root ganglia. Following intraneural injection of RCA into the three main forelimb nerves, namely the radial, ulnar and median nerves, terminal degeneration of the primary afferent fibres in the ECN was studied under the light microscope by means of the Fink-Heimer method. The results show that the primary afferent fibres from these three nerves project to the medial part of the ECN. The field of terminal degeneration take a crescentic form. The projection from the median nerve was most dorsally located whereas that from the radial nerve was the most ventral with extensive overlaps between them. Of the three nerves, the projection from the radial nerve was the most dense. Rostrocaudally, the three nerves also show extensive overlaps. The rostrocaudal extent of maximum terminal degeneration was greatest for the radial nerve and least for the median nerve. Analysis of variance showed that these differences were statistically significant. This suggests that the radial nerve has the most extensive projection to the ECN and the median nerve the least.

Role of metabolism in ethyl carbamate-induced suppression of antibody response to sheep erythrocytes in female Balb/C mice

A possible role of metabolism by cytochrome P450 (P450) in ethyl carbamate-induced suppression of the antibody response to a T-cell-dependent antigen, sheep erythrocytes (SRBCs), was investigated in female Balb/C mice. When mice were treated with ethyl carbamate intraperitoneally for 14 consecutive days at 25, 50, 100, 200 and 400 mg/kg, the antibody response was significantly suppressed from 200 mg/kg. These doses also caused a decrease in thymus weight. An acute dosing of ethyl carbamate at 1 g/kg also caused not only a significant suppression of the antibody response, but also a decrease in thymus weight. The antibody response was most likely to be the IgM antibody response, which was demonstrated in a haemagglutination study. When mice were pretreated with phenobarbital (80 mg/kg) for 3 days to induce P450 enzymes, followed by administration of ethyl carbamate intraperitoneally for 7 consecutive days, the antibody response was more suppressed than in saline-pretreated controls. Moreover, a study using aminoacetonitrile, a P450 inhibitor, showed that the antibody response suppressed by ethyl carbamate was completely recovered by the inhibitor. The present results suggest that metabolism of ethyl carbamate by P450 may be the critical pathway to produce metabolites capable of suppressing the antibody response.