Immunological analysis of hybrid neoantigen peptide encompassing class I/II neoepitope-pulsed dendritic cell vaccine

Neoantigens/ are tumor-specific antigens that evade central immune tolerance mechanisms in the thymus. Long-term tumor-specific cytotoxic T lymphocyte activity maintenance requires class II antigen-reactive CD4+ T cells. We had previously shown that intranodal vaccination with class I neoantigen peptide-pulsed dendritic cells (DCs) induced a robust immune response in a subset of patients with metastatic cancer. The present study aimed to perform a detailed ex vivo analysis of immune responses in four patients receiving an intranodal hybrid human leukocyte antigen class II neoantigen peptide encompassing a class I neoantigen epitope (hybrid neoantigen)-pulsed DC vaccine. After vaccination, strong T-cell reactions against the hybrid class II peptide and the class I-binding neoantigen peptide were observed in all four patients. We found that hybrid class II neoantigen peptide-pulsed DCs stimulated CD4+ T cells via direct antigen presentation and CD8+ T cells via cross-presentation. Further, we demonstrated that hybrid class II peptides encompassing multiple class I neoantigen epitope-pulsed DCs could present multiple class I peptides to CD8+ T cells via cross-presentation. Our findings provide insight into the mechanisms underlying hybrid neoantigen-pulsed DC vaccine therapy and suggest future neoantigen vaccine design.

Congenital anemia reveals distinct targeting mechanisms for master transcription factor GATA1

Master regulators, such as the hematopoietic transcription factor (TF) GATA1, play an essential role in orchestrating lineage commitment and differentiation. However, the precise mechanisms by which such TFs regulate transcription through interactions with specific cis-regulatory elements remain incompletely understood. Here, we describe a form of congenital hemolytic anemia caused by missense mutations in an intrinsically disordered region of GATA1, with a poorly understood role in transcriptional regulation. Through integrative functional approaches, we demonstrate that these mutations perturb GATA1 transcriptional activity by partially impairing nuclear localization and selectively altering precise chromatin occupancy by GATA1. These alterations in chromatin occupancy and concordant chromatin accessibility changes alter faithful gene expression, with failure to both effectively silence and activate select genes necessary for effective terminal red cell production. We demonstrate how disease-causing mutations can reveal regulatory mechanisms that enable the faithful genomic targeting of master TFs during cellular differentiation.

A Case of Congenital Leukemia With MYB-GATA1 Fusion Gene in a Female Patient

We report a female newborn with acute myelogenous leukemia (AML) associated with a MYB-GATA1 fusion gene. Morphologic findings of myeloid lineage were obtained using light microscopy. Cytogenetic analysis of peripheral blood showed a complex karyotype: 46,X,-X,add(3)(q21),der(6)add(6)(q21)del(6)(q?), +mar1[5]/46,XX[15]. Targeted RNA sequencing revealed a MYB-GATA1 fusion gene. Reduced-dose AML-type chemotherapy resulted in remission and survival for >3 years without relapse. The present case demonstrated the feasibility of carrying out targeted RNA sequencing for identifying MYB-GATA1 and supports the notion that neonatal AML with MYB-GATA1 with reduced chemotherapy may show better prognosis than other highly toxic therapies.

Contribution of pre-existing neoantigen-specific T cells to a durable complete response after tumor-pulsed dendritic cell vaccine plus nivolumab therapy in a patient with metastatic salivary duct carcinoma

Although immune checkpoint inhibitors (ICIs) have emerged as new therapeutic options for refractory cancer, they are only effective in select patients. Tumor antigen-pulsed dendritic cell (DC) vaccine therapy activates tumor-specific cytotoxic T lymphocytes, making it an important immunotherapeutic strategy. Salivary ductal carcinoma (SDC) carries a poor prognosis, including poor long-term survival after metastasis or recurrence. In this study, we reported a case of refractory metastatic SDC that was treated with a tumor lysate-pulsed DC vaccine followed by a single injection of low-dose nivolumab, and a durable complete response was achieved. We retrospectively analyzed the immunological factors that contributed to these long-lasting clinical effects. First, we performed neoantigen analysis using resected metastatic tumor specimens obtained before treatment. We found that the tumor had 256 non-synonymous mutations and 669 class I high-affinity binding neoantigen peptides. Using synthetic neoantigen peptides and ELISpot analysis, we found that peripheral blood mononuclear leukocytes cryopreserved before treatment contained pre-existing neoantigen-specific T cells, and the cells obtained after treatment exhibited greater reactivity to neoantigens than those obtained before treatment. Our results collectively suggest that the rapid and long-lasting effect of this combination therapy in our patient may have resulted from the presence of pre-existing neoantigen-specific T cells and stimulation and expansion of those cells following tumor lysate-pulsed DC vaccine and ICI therapy.

Efficacy of Intranodal Neoantigen Peptide-pulsed Dendritic Cell Vaccine Monotherapy in Patients With Advanced Solid Tumors: A Retrospective Analysis

BACKGROUND/AIM

Neoantigens are tumor-specific antigens that emerge due to gene mutations in tumor cells, and are highly antigenic epitopes that escape central immune tolerance in the thymus, making cancer vaccine therapy a desirable option.

PATIENTS AND METHODS

Tumor neoantigens were predicted in 17 patients with advanced cancer. They were resistant to the standard treatment regime, and their synthetic peptides were pulsed to the patient's monocyte-derived dendritic cells (DCs), and administered to the patient's lymph nodes via ultrasound.

RESULTS

Some patients showed sustained tumor shrinkage after this treatment, while some did not respond, showing no ELISpot reaction. Although the number of mutations and the predicted neoantigen epitopes differed between patients, the clinical effect depended more on the presence or absence of an immune response after vaccination rather than the number of neoantigens.

CONCLUSION

Intranodal neoantigen peptide-pulsed DC vaccine administration therapy has clinical and immunological efficacy and safety.

Factor X Deficiency with Heterozygous Mutations of Novel p.G435S and Known p.G244R in a Patient Presenting with Severe Umbilical Hemorrhage

A 10-day-old male patient was referred to our hospital with severe umbilical bleeding. Prothrombin time (PT) and activated partial thromboplastin time (APTT) were prominently prolonged. Plasma coagulation factor X (FX) activity and antigen levels were 1% and 0.6%, respectively. A DNA sequence analysis of his leukocytes revealed a compound heterozygous state; known Gly244 to Arg (p.G244R) in exon 6 and a novel mutation of Gly 435 to Ser (p.G435S) in exon 8. A pedigree analysis showed that p.G244R originated from the paternal side, while p.G435S was from the maternal side. A p.G244R mutation was reported previously as FX_Debrecen and this mutated protein was synthesized as a non-secretable protein. The glycine at amino acid position 435 in the C-terminal region is completely conserved in the trypsin-like serine protease family, including thrombin, FVII, protein C, plasmin, trypsin, and chymotrypsin. In a three-dimensional structural model of FX, Gly 435 was located within the 11^th β-strand and buried in the back of the catalytic pocket. Therefore, the substitution to serine was expected to disrupt this structure. p.G435S FX was also predicted to be synthesized and exist in the cytoplasm, but not to be secreted into culture media by a cDNA expression assay. These two mutations may be responsible for the type 1 (null levels of both activity and antigen in plasma) FX deficiency with severe bleeding phenotype.

Nanotherapy with hybrid liposomes for colorectal cancer along with apoptosis in vitro and in vivo

AIM

We examined the therapeutic effects of hybrid liposomes (HL) composed of L-α-dimyristylphosphati-dylcholine (DMPC) and polyoxyethylene (25) dodecyl ether (C12(EO)25) on the growth of human colorectal cancer (WiDr) cells in vitro and in vivo.

MATERIALS AND METHODS

HL composed of 95 mol% DMPC and 5 mol% C12(EO)25 were prepared by the sonication method and their therapeutic effects in xenograft mouse models of colorectal cancer liver metastases were examined in vivo.

RESULTS

The inhibitory effects of HL-25 on the growth of WiDr cells along with apoptosis were assessed in vitro. Remarkable inhibitory effects of HL-25 for the liver metastasis of colorectal cancer cells along with apoptosis were revealed on the basis of histological analysis. Prolonged survival was attained for the xenograft mouse model of colorectal cancer after treatment with HL-25 in vivo.

CONCLUSION

Therapeutic effects of HL-25 without any drugs on the liver metastasis of human colorectal cancer were obtained for the first time in vivo.

Infantile neuroblastoma of the urinary bladder detected by hematuria

Malignant tumors of the urinary bladder in infants are extremely rare. Rhabdomyosarcoma is the most likely tumor in this site, whereas neuroblastoma of the urinary bladder is exceedingly uncommon and is not listed as a differential diagnosis for tumors of this site. We present a case of neuroblastoma arising from the dome of the bladder wall, detected by hematuria. Only six cases of neuroblastoma originating from the bladder, including the present case have been reported. Of the cases, five arose from the dome of the bladder wall. In this report, the differential diagnosis of bladder tumors in children is discussed. A diagnosis of neuroblastoma should be taken into consideration, especially in the case of tumors arising from the dome of the bladder wall despite an uncommon location.

Therapeutic effects of autologous lymphocytes activated with trastuzumab for xenograft mouse models of human breast cancer

Trastuzumab (TTZ) is molecular targeted drug used for metastatic breast cancer patients overexpressing human epidermal growth factor receptor 2 (HER2). Therapeutic effects of lymphocytes activated with TTZ (TTZ-LAK) using xenograft mouse models of human breast cancer (MDA-MB-453) cells were examined in vivo. Remarkable reduction of tumor volume in a xenograft mouse models intravenously treated with TTZ-LAK cells after the subcutaneously inoculated of MDA-MB-453 cells was verified in vivo. The migration of TTZ-LAK cells in tumor of mouse models subcutaneously inoculated MDA-MB-453 cells was observed on the basis of histological analysis using immunostaining with CD-3. Induction of apoptosis in tumor of xenograft mice treated with TTZ-LAK cells was observed in micrographs using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) method. It was noteworthy that the therapeutic effects of TTZ-LAK cells along with apoptosis were obtained for xenograft mouse models of human breast tumor in vivo.

Targeted induction of interferon-λ in humanized chimeric mouse liver abrogates hepatotropic virus infection

BACKGROUND & AIMS

The interferon (IFN) system plays a critical role in innate antiviral response. We presume that targeted induction of IFN in human liver shows robust antiviral effects on hepatitis C virus (HCV) and hepatitis B virus (HBV).

METHODS

This study used chimeric mice harboring humanized livers and infected with HCV or HBV. This mouse model permitted simultaneous analysis of immune responses by human and mouse hepatocytes in the same liver and exploration of the mechanism of antiviral effect against these viruses. Targeted expression of IFN was induced by treating the animals with a complex comprising a hepatotropic cationic liposome and a synthetic double-stranded RNA analog, pIC (LIC-pIC). Viral replication, IFN gene expression, IFN protein production, and IFN antiviral activity were analyzed (for type I, II and III IFNs) in the livers and sera of these humanized chimeric mice.

RESULTS

Following treatment with LIC-pIC, the humanized livers of chimeric mice exhibited increased expression (at the mRNA and protein level) of human IFN-λs, resulting in strong antiviral effect on HBV and HCV. Similar increases were not seen for human IFN-α or IFN-β in these animals. Strong induction of IFN-λs by LIC-pIC occurred only in human hepatocytes, and not in mouse hepatocytes nor in human cell lines derived from other (non-hepatic) tissues. LIC-pIC-induced IFN-λ production was mediated by the immune sensor adaptor molecules mitochondrial antiviral signaling protein (MAVS) and Toll/IL-1R domain-containing adaptor molecule-1 (TICAM-1), suggesting dual recognition of LIC-pIC by both sensor adaptor pathways.

CONCLUSIONS

These findings demonstrate that the expression and function of various IFNs differ depending on the animal species and tissues under investigation. Chimeric mice harboring humanized livers demonstrate that IFN-λs play an important role in the defense against human hepatic virus infection.

Nationwide survey of bisphosphonate therapy for children with reactivated Langerhans cell histiocytosis in Japan

BACKGROUND

Several studies have suggested that Langerhans cell histiocytosis (LCH) is responsive to treatment with bisphosphonates (BPs). However the efficacy and safety of BPs therapy for childhood LCH is unknown.

PROCEDURE

Data on children with LCH who had received BPs therapy were collected retrospectively from hospitals participating in the Japanese Pediatric Leukemia/Lymphoma Study Group.

RESULTS

Twenty-one children with histologically proven LCH were identified. Of these, the case histories of 16 children who had been treated with pamidronate (PAM) for disease reactivation were analyzed in detail. The median post-PAM therapy follow-up period was 2.8 years (range: 0.9-9.3 years). The median age at commencement of PAM therapy was 9.4 years (range: 2.3-15.0 years). All children had one or more bone lesions but none had risk organ (RO) involvement. In the majority of the children, six courses of PAM were administered at a dose of 1.0 mg/kg/course at 4-week intervals. In 12 of the 16 children, all active lesions including lesions of the skin (n = 3) and soft tissues (n = 3) resolved. Of these children, eight children had no active disease for a median of 3.3 years post-PAM therapy (range: 1.8-9.3 years). Progression-free survival (PFS) was 56.3 ± 12.4% at 3 years. PFS was significantly higher in children with a first reactivation compared with children experiencing a second or subsequent reactivation.

CONCLUSIONS

PAM may be an effective treatment for reactivated LCH with bone lesions. A prospective trial of the efficacy of PAM in recurrent pediatric LCH is warranted.

A case of partial 14q- with facial features of holoprosencephaly and hydranencephaly

We report a rare case of facial features of holoprosencephaly associated with hydranencephaly, with a de novo proximal interstitial deletion of the long arm of chromosome 14, specifically, del(14)(q13q21). She was born at 37 weeks of gestation and transferred to our institution at 3 years of age. The patient had midline facial anomalies consisting of cleft palate, defective nasal septum, and hypotelorism, together with endocrine abnormalities such as diabetes insipidus and hypothyroidism. Cranial computed tomography revealed the near-total loss of all cerebral tissue, with a frontal part of the cerebral falx lacking. None of the few reports of holoprosencephaly with 14q- chromosomal abnormality describe holoprosencephaly in association with hydranencephaly. The partial deletion of chromosome 14, del(14)(q13q21), may underlie the association of facial features of holoprosencephaly and hydranencephaly.

Hsp90 inhibitors suppress HCV replication in replicon cells and humanized liver mice

Persistent infection with hepatitis C virus (HCV) is a major cause of liver diseases such as chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. Here we report that inhibition of heat shock protein 90 (Hsp90) is highly effective in suppressing HCV genome replication. In HCV replicon cells, HCV replication was reduced by Hsp90 inhibitors and by knockdown of endogenous Hsp90 expression mediated by small-interfering RNA (siRNA). The suppression of HCV replication by an Hsp90 inhibitor was prevented by transfection with Hsp90 expression vector. We also tested the anti-HCV effect of Hsp90 inhibition in HCV-infected chimeric mice with humanized liver. Combined administration of an Hsp90 inhibitor and polyethylene glycol-conjugated interferon (PEG-IFN) was more effective in reducing HCV genome RNA levels in serum than was PEG-IFN monotherapy. These results suggest that inhibition of Hsp90 could provide a new therapeutic approach to HCV infection.

Gene-expression profiling reveals down-regulation of equilibrative nucleoside transporter 1 (ENT1) in Ara-C-resistant CCRF-CEM-derived cells

We have investigated the mechanism of resistance of leukemia cells to Ara-C using an in-house cDNA microarray designed for the analysis of leukemia cells. We produced Ara-C-resistant cells from the CCRF-CEM (acute lymphoblastic leukemia) cell line and compared their gene-expression profile with that of wild-type cells. The adenosine deaminase (ADA) gene was highly up-regulated in Ara-C-resistant cells, while equilibrative nucleoside transporter 1 (ENT1) and several cell-cycle-related genes were down-regulated. Of all these genes, ENT1 seemed the most likely to be relevant to Ara-C resistance. To investigate the role of ENT1 in Ara-C-resistant cells, we transfected the cells with the gene. ENT1-transfected Ara-C-resistant cells resembled wild-type CCRF-CEM cells more closely than untransfected Ara-C-resistant cells in terms of growth rate, Ara-C-uptake characteristics, and ADA expression levels. The down-regulation of the ENT1 gene is expected to result in nucleotide deficiency in addition to blockage of Ara-C influx. Accordingly, Ara-C-resistant cells showed low growth rates, which were restored by transfection with ENT1. These low growth rates were also correlated with the phosphorylation level of cell-cycle checkpoint kinase 2. In this study we identified down-regulation of ENT1 as the factor responsible for Ara-C resistance, and this knowledge may be used to devise a clinical regimen that will overcome the resistance.

Breast cancer with choriocarcinomatous features: A case report with cytopathologic details

A case of breast cancer with choriocarcinomatous features (BCCF) is reported. The patient was a 38-year-old Japanese female with a long history of schizophrenia. Her nursing staff noticed a palpable mass in her right breast, which showed rapid growth. Following cytopathologic confirmation of a malignant breast tumor, she underwent mastectomy with ipsilateral axillary lymph node dissection. Histologic examination revealed BCCF, which was positive for placental alkaline phosphatase and human chorionic gonadotropin (HCG) by immunohistochemistry. The serum HCG level was high. She died 7 months postoperatively, with multiple metastases of BCCF to the chest wall, lung and liver.

[A case of "forme fruste" of tuberous sclerosis having been treated as genuine epilepsy]

A 30-year-old man had signs of a lumbosacral skin plaque, called "shagreen patch", and mental retardation. He had been treated as genuine epilepsy for more than twenty years. Neither significant abnormalities nor facial angiofibroma (adenoma sebaceum) were detected on physical and neurological examinations. Brain CT revealed calcified subependymal nodules. A T2-weighted brain MRI presented high signal intensity regions affecting the cerebral cortex, which suggested tuberous lesions. Echocardiography showed high echoic lesions on the left ventricular wall and papillary muscles, suggesting calcification. The case was diagnosed as suffering from "forme fruste" of tuberous sclerosis. The three criteria typical of tuberous sclerosis (facial angiofibroma, seizure and mental retardation) were not satisfied. The "forme fruste" variant is less known, because the pattern of involvement varies, and it may clinically simulate genuine epilepsy.