The translation elongation factor eEF2 is a novel tumor‑associated antigen overexpressed in various types of cancers

Recent studies have shown that cancer immunotherapy could be a promising therapeutic approach for the treatment of cancer. In the present study, to identify novel tumor-associated antigens (TAAs), the proteins expressed in a panel of cancer cells were serologically screened by immunoblot analysis and the eukaryotic elongation factor 2 (eEF2) was identified as an antigen that was recognized by IgG autoantibody in sera from a group of patients with head and neck squamous cell carcinoma (HNSCC) or colon cancer. Enzyme-linked immunosorbent assay showed that serum eEF2 IgG Ab levels were significantly higher in colorectal and gastric cancer patients compared to healthy individuals. Immunohistochemistry experiments showed that the eEF2 protein was overexpressed in the majority of lung, esophageal, pancreatic, breast and prostate cancers, HNSCC, glioblastoma multiforme and non-Hodgkin's lymphoma (NHL). Knockdown of eEF2 by short hairpin RNA (shRNA) significantly inhibited the growth in four eEF2-expressing cell lines, PC14 lung cancer, PCI6 pancreatic cancer, HT1080 fibrosarcoma and A172 glioblastoma cells, but not in eEF2-undetectable MCF7 cells. Furthermore, eEF2-derived 9-mer peptides, EF786 (eEF2 786-794 aa) and EF292 (eEF2 292-300 aa), elicited cytotoxic T lymphocyte (CTL) responses in peripheral blood mononuclear cells (PBMCs) from an HLA-A*24:02- and an HLA-A*02:01-positive healthy donor, respectively, in an HLA-A-restricted manner. These results indicated that the eEF2 gene is overexpressed in the majority of several types of cancers and plays an oncogenic role in cancer cell growth. Moreover, the eEF2 gene product is immunogenic and a promising target molecule of cancer immunotherapy for several types of cancers.

Chromosomal and genetic abnormalities in benign and malignant meningiomas using DNA microarray

BACKGROUND

Meningioma is the commonest brain tumor and many genetic abnormalities, such as the loss of chromosome 22q and the mutation of NF2, have been reported.

METHODS

These classical abnormalities were detected using Southern blot, PCR, fluorescence in situ hybridization and comparative genomic hybridization, but these methods examine only very limited regions or limited mapping resolution of the tumor genome. In this study, we used DNA microarray assay, which detects numerous genetic abnormalities simultaneously and analyses a global assessment of molecular events in meningioma cells. We studied 31 meningiomas by GenoSensor Array 300 in order to detect the chromosomal aberrations and genetic abnormalities in the whole genome.

RESULTS

This study demonstrated not only classical chromosomal aberration, such as loss of chromosome 22q in 19 meningiomas (61.3%), but also new genetic characteristics of meningiomas, such as amplification of MSH2 in 16 meningiomas (51.6%), deletion of GSCL in 13 meningiomas (41.9%) and deletion of HIRA in seven meningiomas (22.6%).

CONCLUSIONS

These results suggest that DNA microarray assay is useful in research for the genetic characters of meningiomas and understanding tumorigenesis.

Biased usage of T cell receptor β-chain variable region genes of Wilms' tumor gene (WT1)-specific CD8+ T cells in patients with solid tumors and healthy donors

Wilms' tumor gene 1 (WT1) protein is a promising tumor-associated antigen. In patients with WT1-expressing malignancies, WT1-specific CTLs are spontaneously induced as a result of an immune response to the WT1 protein. In the present study, we performed single cell-level comparative analysis of T cell receptor β-chain variable region (TCR-BV) gene families of a total of 750 spontaneously induced WT1(126) peptide (amino acids 126-134, WT1(126))-specific CTLs in both HLA-A*0201(+) patients with solid tumors and healthy donors (HDs). This is the first report of direct usage analysis of 24 kinds of TCR-BV gene families of WT1(126)-specific CTLs at the single cell level. Usage analysis with single-cell RT-PCR of TCR-BV gene families of individual FACS-sorted WT1(126) tetramer(+) CD8(+) T cells showed, for the first time, that: (i) BVs 3, 6, 7, 20, 27, and 28 were commonly biased in patients and HDs; (ii) BVs 2, 11, and 15 were biased only in patients; and (iii) BVs 4, 5, 9, and 19 were biased only in HDs. However, statistical analysis of similarity of individual usage frequencies of 24 kinds of TCR-BV gene families between patients and HDs indicated that the usage frequencies of TCR-BV gene families in patients reflected those in HDs. These results should provide us with a novel insight for a better understanding of WT1-specific immune responses.

Posttransplant lymphoproliferative disorders of the central nervous system after kidney transplantation: single center experience over 40 years. Two case reports

Posttransplant lymphoproliferative disorder (PTLD) is one of the life-threatening complications of organ transplantation. PTLD sometimes involves the central nervous system (CNS), but the clinical characteristics are not well recognized. A total of 631 patients received kidney transplantation at Osaka University Hospital between March 1965 and December 2008. Two of the 631 patients (0.32%) developed CNS PTLD. A 40-year-old Japanese woman suffered onset of CNS PTLD 5 years after renal transplantation. After diagnosis based on histological examination by open biopsy, she obtained remission with dose increase of steroid and dose reduction of mycophenolate mofetil. She experienced relapse 20 months after first remission. She underwent second biopsy and the diagnosis was recurrent CNS PTLD. Further reduction of mycophenolate mofetil and increase of steroid led to second remission. The disease remained in complete remission at 60 months after first onset. A 61-year-old woman suffered onset of CNS PTLD 19 years after renal transplantation. After tumor removal, whole brain irradiation was performed. The disease remained in remission at 54 months after onset. Histological examination showed polymorphic-type PTLD in both cases. The first case of polymorphic CNS PTLD was successfully treated by modulation of immunosuppressants without radiation therapy even at recurrence. PTLD should be included in the differential diagnosis of brain tumors in recipients of solid organ transplantation, and histological subtype should be carefully identified to establish the correct treatment strategy.

A clear correlation between WT1-specific Th response and clinical response in WT1 CTL epitope vaccination

Clinical studies of WT1-targeted cancer vaccine are being performed. However, WT1-specific Th response in cancer patients remains unclear. Using quantitative real-time RT-PCR, we investigated IFN-gamma and IL-10 mRNA expression from Th cells by stimulation with helper peptide WT1(332). Seventeen patients, of whom 10 had achieved stable disease and the remaining 7 had progressive disease, were weekly vaccinated with WT1 CTL epitope (modified WT1(235)) and examined for WT1(332)-specific Th response. A clear correlation between WT1(332)-specific Th response and clinical response was observed at 4 weeks post-vaccination. In patients who responded, a clear inverse correlation between IL-10-type and IFN-gamma-type WT1(332)-specific Th response was detected at pre- and 4 weeks post-vaccination, and the shift of the Th response from IL-10-type dominancy at early phase to IFN-gamma-type dominancy at late phase was observed. From this study we concluded that occurrence of WT1(332)-specific Th response could predict good clinical response of WT1 CTL epitope vaccination.

Scoring radiologic characteristics to predict proliferative potential in meningiomas

We investigated the feasibility of using radiologic characteristics to predict the proliferative potential in meningiomas. Our statistical analysis revealed that the presence of peritumoral edema, an ambiguous brain-tumor border, and irregular tumor shape were significantly correlated with a higher MIB-1 staining index (SI) value. We developed the following scoring system for specific features in each tumor: peritumoral edema (tumor with edema = 1, tumor without edema = 0); brain-tumor border (tumor with any ambiguous border = 1, tumor circumscribed by a distinct rim = 0); and tumor shape (tumor with irregular shape = 1, tumor with smooth shape = 0). Using Spearman's correlation coefficient analysis, we found a significant correlation (P < 0.005) between total score calculated for each patient and SI value. Our findings suggest that the proliferative potential of meningiomas can be predicted using a less invasive preoperative examination focusing on the presence of peritumoral edema, ambiguous brain-tumor border, and irregular tumor shape.

Detection of genetic and chromosomal aberrations in medulloblastomas and primitive neuroectodermal tumors with DNA microarrays

Medulloblastoma (MB) is the most frequent infratentorial malignant brain tumor in children. In contrast, primitive neuroectodermal tumor (PNET) is defined as a supratentorial malignant tumor generated from the cerebral hemisphere. These tumors have considerable histological overlap but have different clinical outcomes including overall survival period, recurrence rate, and chemosensitivity. We investigated the amplification and/or deletion of genes and the chromosomal gain and/or loss in 10 MBs and 3 PNETs with a genomic DNA microarray system. Genes that are frequently amplified in these both these tumors include MSH2, N-myc, AKT3, and EGFR. Amplifications of SNRPN, MYB, and PTEN are observed only in MB. The genes associated with Wnt/APC and Shh/PTCH pathways also have some aberrations. Common chromosomal aberrations include gains at 17q and 7q and losses at 17p. Minor chromosomal losses were also detected at 1p, 8p + q, 11p, 10p + q, 13q, 16q, and Xp + q in MB. SPNETs tend to contain fewer chromosomal and genetic abnormalities than MBs. In conclusion, there are gene expression and chromosomal differences between MBs and SPNETs. These differences may correlate with the prognosis.

[Immunotherapy targeting the Wilms' tumor 1 gene product for patients with malignant brain tumors]

In this paper, we review the current status of immunotherapy targeting Wilms' tumor 1 (WT1) peptide in malignant brain tumors as well as in other hematological and solid malignancies. WT1 is expressed in various kinds of malignancies, and is involved in oncogenesis. The titers of antibodies against WT1 and the frequency of WT1-specific cytotoxic T lymphocytes (CTLs) were higher in cancer patients than in healthy donors, indicating that WT1 protein has immunogenic function. These findings provided us with a rationale for developing cancer immunotherapy that targets the WT1 peptide. Clinical trials of the WT1 peptide vaccination were initiated, and definite immunological and clinical responses were observed. The disease control rate of 57.1% was obtained especially in the case of recurrent glioblastomas, with a median progression-free survival period of 20.0 weeks and progression-free survival rate at 6 months of 33.3%. The trial showed that WT1 vaccination for malignant gliomas, which is generally believed to be an intractable disease, was safe and elicited a favorable clinical response. Further clinical studies of WT1 vaccination in patients with malignant gliomas as well as other cancers are warranted. An enhancement of the efficacy of WT1 vaccination can be expected with a combined treatment using the WT1-specific helper peptide or anti-cancer chemotherapeutic agents. Administration of WT1 vaccination along with other therapeutic modalities during initial treatment or in the case showing minimal residual disease may prolong the survival time of the cancer patients.

Serial volumetric assessment of the natural history and growth pattern of incidentally discovered meningiomas

OBJECT

Due to advances in neuroimaging and the increasing use of imaging to screen for brain disease ("brain checkups"), meningiomas are now often detected as an incidental finding. The natural history of these asymptomatic meningiomas remains unclear, however. In this study, the authors investigated the natural history and growth pattern of incidentally detected meningiomas using serial volumetric assessment and regression analysis.

METHODS

In 70 patients with incidentally discovered meningiomas who underwent follow-up for longer than 1 year, tumor volumes were calculated volumetrically at each follow-up visit, and tumor growth was determined. In patients with tumor growth, regression analysis was performed to determine the pattern of growth.

RESULTS

Forty-four tumors exhibited growth and 26 did not. In a regression analysis, 16 of the tumors that grew followed an exponential growth pattern and 15 exhibited linear growth patterns. The presence of calcification was the only imaging characteristic that significantly distinguished the group with tumor growth from that without, although no radiological characteristics significantly distinguished the exponential growth group from the linear growth group. Two patients with obvious tumor growth underwent surgical removal and the pathological specimens extracted showed a high proliferative potential.

CONCLUSIONS

The authors found that incidentally discovered meningiomas did not always follow an exponential growth pattern but often exhibited more complex patterns of growth. Serial monitoring of tumor volumes and regression analysis may reveal the growth pattern of incidental meningiomas and provide information useful for determining treatment strategy.

Phase II clinical trial of Wilms tumor 1 peptide vaccination for patients with recurrent glioblastoma multiforme

OBJECT

The object of this study was to investigate the safety and clinical responses of immunotherapy targeting the WT1 (Wilms tumor 1) gene product in patients with recurrent glioblastoma multiforme (GBM).

METHODS

Twenty-one patients with WT1/HLA-A*2402-positive recurrent GBM were included in a Phase II clinical study of WT1 vaccine therapy. In all patients, the tumors were resistant to standard therapy. Patients received intra-dermal injections of an HLA-A*2402-restricted, modified 9-mer WT1 peptide every week for 12 weeks. Tumor size, which was obtained by measuring the contrast-enhanced area on magnetic resonance images, was determined every 4 weeks. The responses were analyzed according to Response Evaluation Criteria in Solid Tumors (RECIST) 12 weeks after the initial vaccination. Patients who achieved an effective response continued to be vaccinated until tumor progression occurred. Progression-free survival and overall survival after initial WT1 treatment were estimated.

RESULTS

The protocol was well tolerated; only local erythema occurred at the WT1 vaccine injection site. The clinical responses were as follows: partial response in 2 patients, stable disease in 10 patients, and progressive disease in 9 patients. No patient had a complete response. The overall response rate (cases with complete or partial response) was 9.5%, and the disease control rate (cases with complete or partial response as well as those in which disease was stable) was 57.1%. The median progression-free survival (PFS) period was 20.0 weeks, and the 6-month (26-week) PFS rate was 33.3%.

CONCLUSIONS

Although a small uncontrolled nonrandomized trial, this study showed that WT1 vaccine therapy for patients with WT1/HLA-A*2402-positive recurrent GBM was safe and produced a clinical response. Based on these results, further clinical studies of WT1 vaccine therapy in patients with malignant glioma are warranted.

Reduced epinephrine reserve in response to insulin-induced hypoglycemia in patients with pituitary adenoma

OBJECTIVE

Hypoglycemia induces rapid secretion of counterregulatory hormones such as catecholamine, glucagon, cortisol, and GH. Insulin-induced hypoglycemia is used for evaluating GH-IGF-I and ACTH-adrenal axes in patients with pituitary disorders. The aim of this study was to determine whether the response of catecholamine secretion to hypoglycemia is disrupted in patients with pituitary adenoma.

METHODS

The study population comprised 23 patients with pituitary adenoma (non-functioning adenoma or prolactinoma). An insulin tolerance test was performed and serum catecholamines as well as plasma GH and serum cortisol were measured.

RESULTS

The study patients showed diminished response of plasma epinephrine to insulin-induced hypoglycemia. With the cutoff level of peak epinephrine for defining severe impairment set at 400 pg/ml, more patients with secondary adrenal insufficiency showed severe impairment of the epinephrine response than did those without it. Peak epinephrine levels to insulin-induced hypoglycemia were significantly correlated with peak cortisol levels. In patients with secondary hypothyroidism, secondary hypogonadism, GH deficiency, or diabetes insipidus, the prevalence of severe impairment of the epinephrine response was similar to that in patients without these deficiencies.

CONCLUSIONS

Impaired epinephrine secretion in response to insulin-induced hypoglycemia was frequently observed in patients with pituitary adenoma. This disorder was especially severe in patients with secondary adrenal insufficiency.

Expression of WT1 protein and correlation with cellular proliferation in glial tumors

The expression of Wilms' tumor gene WT1 protein was investigated immunohistochemically in 73 glial tumors, including 60 astrocytic tumors, eight oligodendroglial tumors, and five ependymal tumors. WT1 protein was detected in 70 of the 73 glial tumors (95.9%) examined. Almost all glioblastomas, anaplastic astrocytomas, anaplastic ependymomas, and anaplastic oligodendrogliomas expressed high levels of WT1 protein. A significant (p < 0.001) correlation was found between WT1 protein expression and MIB-1 staining index. Histological examination found that WT1 protein was strongly expressed in the anaplastic portions and areas with perivascular proliferation and high cellularity, implying that WT1 gene might be important in glial tumor cell proliferation. WT1 gene is overexpressed in various types of solid tumors and WT1 protein is a target antigen for cancer immunotherapy. This study indicates that many malignant glial tumors are good candidates for cancer immunotherapy targeting WT1 protein and that WT1 protein expression could be used as a proliferation marker in glial tumors.

A phase I/II trial of a WT1 (Wilms' tumor gene) peptide vaccine in patients with solid malignancy: safety assessment based on the phase I data

OBJECTIVE

We conducted a phase I study to investigate the safety of a weekly WT1 tumor vaccine therapy in patients with solid tumors that had been refractory to all other anti-cancer therapies.

METHODS

Skin-test-negative patients were intradermally injected weekly for 12 weeks with 3.0 mg of an HLA-A*2402-restricted modified 9-mer WT1 peptide emulsified in Montanide ISA51 adjuvant. We estimated the Bayesian posterior probability of the occurrence of grade 3 or 4 toxicity when receiving the weekly WT1 vaccination. This analysis provided the basis for making a decision to terminate the phase I study and switch to phase II. Moreover, we performed an exploratory assessment of the anti-tumor effects of WT1 treatment.

RESULTS

Ten patients received 114 vaccinations with WT1 on a weekly schedule. No grade 3 or 4 toxicities were observed. Based on the Bayesian approach, it was highly likely that the probability of grade 3 or 4 toxicity was below 20% (the posterior probability = 0.914). Fifteen grade 2 and two grade 1 toxicities were observed; all of these incidents, however, were determined by the Independent Data and Safety Monitoring Committee to be unrelated to the WT1 treatment. One patient exhibited a partial response; five additional patients had stable disease while receiving weekly WT1 treatment.

CONCLUSION

This paper confirms that the potential toxicities of the treatment schedule of weekly WT1 vaccination are acceptable and suggested a potential anti-tumor effect. Consequently, we validated the decision to continue to the phase II trial.

Short-term preoperative octreotide treatment of GH-secreting pituitary adenoma: predictors of tumor shrinkage

We reviewed the cases of 32 patients with growth hormone (GH)-secreting macroadenoma who underwent short-term octreotide treatment before transsphenoidal surgery to determine which types of adenoma the preoperative treatment were sensitive and whether predictors of tumor shrinkage could be identified. The effects of preoperative octreotide treatment, endocrinologic effect and effect on tumor volume in 32 patients were evaluated retrospectively in relation to tumor features on magnetic resonance images and responses to endocrinologic challenge tests. At a daily dose of 300 microg for 2-3 weeks, octreotide reduced serum GH and insulin-like growth factor-1 (IGF-1) levels to 31.9 % and 51.6% of pretreatment values, respectively, and led to a mean tumor volume of 68% of pretreatment volume in 52% of the patients. The endocrinologic effect and the effect on tumor volume were larger in Knosp grades 0-2 than in Knosp grades 3-4. Tumor shrinkage occurred significantly more often among patients that had a good response to both octreotide and bromocriptine challenge tests. For surgical removal of the tumor, the effect of reducing tumor to 68% of pretreatment volume will be beneficial for the macroadenomas of Knosp grades 1-2. Preoperative short-term octreotide treatment is effective for GH-secreting macroadeomas of Knosp grades 1-2 and a good response to both octreotide and bromocriptine challenge tests is a predictor of subsequent tumor shrinkage. These results will lead to more effective selection of patients for preoperative octreotide treatment.

Inhibition of Glioma Cell Proliferation by Neural Stem Cell Factor

Neural stem cells (NSC) have unique differentiation-, proliferation-, and motility properties. To investigate whether they secrete factors that interfere with the proliferation of glioma cells, we grew glioma cells in conditioned medium (CM) obtained from cultures of neurospheres including neural stem / progenitor cells (NSPC) isolated from embryonic (E14)- or adult mouse brain or fetal human brain. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and BrdU-labeling assays showed that CM from NSPC (NSPC/CM) contained factor(s) that inhibited the proliferation of glioma cells by 28-87%. Filter-fractionation of NSPC/CM revealed that the 50,000-100,000 nominal molecular weight limit (NMWL) fraction contained the inhibitory activity. On the basis of these observations we transplanted 203G glioma cells and/or NSPC into the intrathecal space of the cisterna magna of mice to investigate whether NSPC interfere with the proliferation of glioma cells in vivo. Mice transplanted with both 203G and NSPC survived significantly longer than did mice transplanted only with 203G. We concluded that NSPC secrete factor(s) that may control glioma cell proliferation.

Ganglioside GM3 inhibits proliferation and invasion of glioma

GM3, the simplest ganglioside, modulates cell adhesion, proliferation and differentiation in the central nervous system and exogenously added GM3 regulates cell-cell and cell-extracellular matrix adhesion and induces apoptosis. To assess the anti-tumor action of exogenous GM3, we examined its effect on the proliferation and invasion of glioma cells. Its inhibitory effect on cell proliferation was demonstrated in vitro by 3-(4,5-dimethyl-2-thiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) assay and in vitro in rats with meningeal gliomatosis whose survival was significantly prolonged by the intrathecal injection of GM3. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) assay revealed that GM3 induced glioma cell apoptosis in vitro and in vitro. In rat brain slice cultures, GM3 suppressed the invasion of glioma cells; this effect manifested earlier than the inhibition of cell proliferation and before apoptosis induction. Our results suggest exogenous GM3 as a potential therapeutic agent in patients with glioma requiring adjuvant therapy.

Immunohistochemical detection of female sex hormone receptors in craniopharyngiomas: correlation with clinical and histologic features

BACKGROUND

Although craniopharyngiomas have a histologically benign nature, their treatment can be difficult. The correlation among clinical, proliferative, and immunohistologic features of female sex hormone receptors was determined in craniopharyngiomas to analyze whether they influence the growth of the tumor.

METHODS

The study subjects were 43 patients with previously untreated craniopharyngioma who underwent surgery at our department over the past 15 years. Serial tissue sections were immunostained with the antibodies against estrogen receptor (ER), progesterone receptor (PR), and Ki-67.

RESULTS

The Ki-67 labeling index was significantly higher in patients with regrowth (7.8%) than without regrowth (3.9%). ER and PR were detected in 9 of 30 (30%) craniopharyngiomas, and the incidence of postoperative tumor regrowth was significantly higher in patients negative for ER and PR (29%) than in those positive for both receptors (11%).

CONCLUSIONS

A high Ki-67 labeling index suggests a high possibility of tumor regrowth, and the presence of ER and PR is suggestive of a high tissue differentiating potential. ER and PR assay may be useful for determining the indication for additional radiation therapy in craniopharyngioma patients treated by incomplete resection.