Survival and Functional Immune Reconstitution After Haploidentical Stem Cell Transplantation in Atm-Deficient Mice.

Hematopoietic stem cell transplantation (HSCT) has been proposed as a promising therapeutic opportunity to improve immunity and prevent hematologic malignancies in Ataxia-telangiectasia (A-T). However, experience in the transplantation strategy for A-T patients is still scarce. The aim of this study was to investigate whether different approaches of HSCT are feasible in regard to graft versus host response and sufficient concerning functional immune reconstitution. Atm-deficient mice were treated with a clinically relevant non-myeloablative host-conditioning regimen and transplanted with CD90.2-depleted, green fluorescent protein (GFP)-expressing, and ataxia telangiectasia mutated (ATM)-competent bone marrow donor cells in a syngeneic, haploidentical or allogeneic setting. Like syngeneic HSCT, haploidentical HSCT, but not allogeneic HSCT extended the lifespan of Atm-deficient mice through the reduction of thymic tumors and normalized T-cell numbers. Donor-derived splenocytes isolated from transplanted Atm-deficient mice filled the gap of cell loss in the naïve T-cell population and raised CD4 cell functionality up to wild-type level. Interestingly, HSCT using heterozygous donor cells let to a significantly improved survival of Atm-deficient mice and increased CD4 cell numbers as well as CD4 cell functionality equivalent to HSCT using with wild-type donor cells. Our data provided evidence that haploidentical HSCT could be a feasible strategy for A-T, possibly even if the donor is heterozygous for ATM. However, this basic research cannot substitute any research in humans.

Transplantation of Unirradiated Bone Marrow Cells after Total-Body Irradiation Prevents the Development of Thymic Lymphoma in Mice through Niche Competition.

Mouse models of radiation-induced thymic lymphoma are commonly used to study the biological effects of total-body irradiation (TBI) on the formation of hematologic malignancies. It is well documented that radiation-induced thymic lymphoma can be inhibited by protecting the bone marrow (BM) from irradiation; however, the mechanisms underlying this phenomenon are poorly understood. Here, we aimed to address this question by performing transplantation of BM cells from genetically engineered mice that have defects in tumor immunosurveillance or occupying different thymic niches. We found that BM cells from mice that have impaired tumor immunosurveillance, by deleting tumor necrosis factor alpha (TNFα), interferon gamma (IFNγ) or perforin-1 (PRF1), remained sufficient to suppress the formation of radiation-induced thymic lymphoma. On the other hand, BM cells from Rag2-/-; γc-/- mice and Rag2-/- mice, which have defects in occupying thymic niches beyond double negative (DN2) and DN3, respectively, failed to inhibit radiation-induced lymphomagenesis in the thymus. Taken together, based on our findings, we propose a model where unirradiated BM cells suppress radiation-induced lymphomagenesis in the thymus by competing with tumor-initiating cells for thymic niches beyond the DN3 stage.

Survival of malignant mesothelioma and other rare thoracic cancers in Germany and the United States: A population-based study.

Evidence on survival of malignant mesothelioma (MM) and other rare thoracic cancers is limited due to the rarity of these cancer sites. Here, we provide a comprehensive overview of MM incidence and survival after MM and other rare thoracic cancers in Germany and the United States (US). Incidence was estimated from a German National Cancer Database and from the Surveillance, Epidemiology and End Results (SEER) 18 database for 2000-2014. Patients diagnosed in 1997-2013 with malignant epithelial tumors of the trachea (Etra), epithelial tumors of the thymus (Ethy) and MM were extracted from a German cancer survival database and from the SEER 13 database. Period analysis was employed to compute 5-year relative survival (RS). During 2000-2014, an annual average of 0.9 and 0.6 MM cases per 100,000 person-years was diagnosed in Germany and the US. Rates decreased in Germany and in the US. Patients with Ethy had highest 5-year RS with US patients surviving longer (69.1% compared to 63.7%, p = 0.02). Survival after Etra was comparable in both countries (Germany 33.6%, US 34.4%, p = 0.07). Survival in MM patients was poor overall (Germany 11.8%, US 12.1%, p < 0.01). Survival improvements were only observed in MM patients in Germany (10.8% [2002-2007] vs. 13.0% [2008-2013], p < 0.01). The lack of progress in survival for Etra and Ethy patients underlines the need of novel preventive, therapeutic and diagnostic approaches. MM incidence significantly decreased in Germany and in the US. Further monitoring of MM incidence is warranted given that a peak in incidence is expected in 2020-2030 in Western countries.

The STING ligand cGAMP potentiates the efficacy of vaccine-induced CD8+ T cells.

Pathogen recognition receptor (PRR) agonists are currently being developed and tested as adjuvants in various formulations to optimize the immunogenicity and efficacy of vaccines. Using an original in vitro approach to prime naive precursors from unfractionated human peripheral blood mononuclear cells, we assessed the influence of cyclic guanosine monophosphate-adenosine monophosphate (cGAMP), a ligand for the stimulator of interferon genes (STING), on the induction of antigen-specific CD8+ T cells. We found that 2'3'-cGAMP and 3'3'-cGAMP were especially potent adjuvants in this system, driving the expansion and maturation of functionally replete antigen-specific CD8+ T cells via the induction of type I IFNs. The biological relevance of these findings was confirmed in vivo using two mouse models, in which 2'3'-cGAMP-adjuvanted vaccination elicited protective antitumor or antiviral CD8+ T cell responses. These results identify particular isoforms of cGAMP as effective adjuvants that may find utility in the development of novel immunotherapies and vaccines.

Preventive Effects of Fermented Brown Rice and Rice Bran on Spontaneous Lymphomagenesis in AKR/NSlc Female Mice

Fermented brown rice and rice bran with Aspergillus oryzae (FBRA) is known to possess potentials to prevent chemical carcinogenesis in multiple organs of rodents. In the present study, possible chemopreventive effect of FBRA against spontaneous occurrence of lymphomas was examined using female AKR/NSlc mice. Four-week-old female AKR/ NSlc mice were divided into three groups, and fed diets containing FBRA for 26 weeks at a dose level 0% (Group 1), 5% (Group 2) or 10% (Group 3). At the termination of experiment, the incidence of thymic malignant lymphoma of Group 3 was significantly lower than of Group 1 (p < 0.05). The average number of apoptotic cells of the thymic lymphoma of Group 3 was significantly larger than that of Group 1 (p < 0.05). In addition, the incidences of malignant lymphoma arising from body surface and abdominal lymph nodes, and the frequencies of lymphoma cell invasion to liver, kidney, spleen, and ovary of Group 3 were relatively lower than those of Group 1. These results indicate that FBRA inhibits spontaneous development of the lymphoma in female AKR/NSc mice and the inhibition of lymphomagenesis may relate to the induction of apoptosis by exposure of FBRA, suggesting that FBRA could be a protective agent against development of human lymphoma.

No need for constant help: human IgG2 antibodies have an autonomous agonistic activity for immunotherapy of cancer.

Agonistic antibodies specific for members of the tumor necrosis factor receptor protein family hold great promise for immunotherapy of cancer. In this issue of Cancer Cell, White and colleagues provide evidence that the human IgG2 subclass may represent a superior backbone for the use of these antibodies in human therapy.

Conformation of the human immunoglobulin G2 hinge imparts superagonistic properties to immunostimulatory anticancer antibodies.

Monoclonal antibody (mAb) drugs that stimulate antitumor immunity are transforming cancer treatment but require optimization for maximum clinical impact. Here, we show that, unlike other immunoglobulin isotypes, human IgG2 (h2) imparts FcγR-independent agonistic activity to immune-stimulatory mAbs such as anti-CD40, -4-1BB, and -CD28. Activity is provided by a subfraction of h2, h2B, that is structurally constrained due its unique arrangement of hinge region disulfide bonds. Agonistic activity can be transferred from h2 to h1 by swapping their hinge and CH1 domains, and substitution of key hinge and CH1 cysteines generates homogenous h2 variants with distinct agonistic properties. This provides the exciting opportunity to engineer clinical reagents with defined therapeutic activity regardless of FcγR expression levels in the local microenvironment.

Does the mode of surgical resection affect the prognosis/recurrence in patients with thymoma?

BACKGROUND: Among the various controversies in the treatment strategies for patients with thymoma, the optimal mode of resection needs to be defined. To explore whether or not the mode of resection affects the prognosis/recurrence in patients with thymoma, we evaluated the treatment outcome of patients with resected thymoma. METHODS: One hundred seventy-three nonmyasthenic patients with stage I or II resected thymoma were studied. Patients were divided into two groups: a thymomectomy (resection of thymoma without total thymectomy) group (n = 100) and a thymothymomectomy (resection of thymoma with total thymectomy) group (n = 73). The differences in the clinicopathological characteristics and prognosis between the two groups were examined. RESULTS: Myasthenia gravis developed postoperatively in three patients (3%) in the thymomectomy group and in 6 (8%) in the thymothymomectomy group. The 5- and 10-year overall survival rates in the thymomectomy group were 96.7% and 92.2%, and those in the thymothymomectomy group were 94.0% and 86.2%, respectively (P = 0.755). Two patients (2%) in the thymomectomy group and 4 (5%) in the thymothymomectomy group experienced recurrence. CONCLUSIONS: There was no difference in prognosis/recurrence between the two groups. Thymothymomectomy might not always be necessary for nonmyasthenic patients with stage I or II thymoma.

Role of Red Meat and Resistant Starch in Promutagenic Adduct Formation, MGMT Repair, Thymic Lymphoma and Intestinal Tumourigenesis in Msh2 -Deficient Mice.

Red meat may increase promutagenic lesions in the colon. Resistant starch (RS) can reduce these lesions and chemically induced colon tumours in rodents. Msh2 is a mismatch repair (MMR) protein, recognising unrepaired promutagenic adducts for removal. We determined if red meat and/or RS modulated DNA adducts or oncogenesis in Msh2-deficient mice. A total of 100 Msh2-/- and 60 wild-type mice consumed 1 of 4 diets for 6 months: control, RS, red meat and red meat+RS. Survival time, aberrant crypt foci (ACF), colon and small intestinal tumours, lymphoma, colonic O6-methyl-2-deoxyguanosine (O6MeG) adducts, methylguanine methyltransferase (MGMT) and cell proliferation were examined. In Msh2-/- mice, red meat enhanced survival compared to control (p<0.01) and lowered total tumour burden compared to RS (p<0.167). Msh2-/- mice had more ACF than wild-type mice (p<0.014), but no colon tumours developed. Msh2-/- increased cell proliferation (p<0.001), lowered DNA O6MeG adducts (p<0.143) and enhanced MGMT protein levels (p<0.001) compared to wild-type mice, with RS supplementation also protecting against DNA adducts (p<0.01). No link between red meat-induced promutagenic adducts and risk for colorectal cancer was observed after 6 months' feeding. Colonic epithelial changes after red meat and RS consumption with MMR deficiency will differ from normal epithelial cells.

[Inhibitory effects of sporoderm-broken Ganoderma lucidum spores on growth of lymphoma implanted in nude mouse].

This study was aimed to investigate the inhibitory effects of sporoderm-broken ganoderma lucidum spores (GLS) on transplanted lymphoma in nude mice and its mechanism. The models of the subcutaneously transplanting tumor were established by N-methylnitrosourea-induced thymus T-cell lymphoma. The cellular apoptosis of tumor tissues in nude mice were observed by transmission electron microscopy (TEM), the mRNA expression of Bax, Bcl-2, Bcl-xl was determined by RT-PCR. The results indicated that the GLS had a certain anti-tumor effect, and the inhibitory rate was 45.8 with the dose of 4 g/kg (ig, once daily for 21 d). Apoptotic cells in lymphoma cells treated with GLS were observed by TEM. RT-PCR analysis showed that the expression of Bax was up-regulated, Bcl-2 and Bcl-xl were down-regulated in T-cell lymphoma cells. It is concluded that GLS can inhibit proliferation of lymphoma cells and induce the lymphoma cell apoptosis, the mechanism of which may be related with up-regulating the expression of Bax and down-regulating the expression of Bcl-2 and Bcl-xl.

Pharmacological blockade of Bcl-2, Bcl-x(L) and Bcl-w by the BH3 mimetic ABT-737 has only minor impact on tumour development in p53-deficient mice.

The tumour suppressor p53 transcriptionally regulates a range of target genes that control cell growth and survival. Mutations of p53 have been implicated in the development of approximately 50% of human cancers, including those instigated by exposure to mutagens. Although numerically rare, cancers can arise as a consequence of inherited mutations, such as in the Li-Fraumeni syndrome, which is caused by mutation of one p53 allele. Gene-targeted mice deficient for p53 have been generated to study this familial cancer syndrome. On a C57BL/6 background, p53-deficient mice develop primarily thymic lymphoma and more rarely sarcoma. Evasion of apoptosis is considered to be essential for neoplastic transformation. As proteins of the Bcl-2 family are the critical regulators of apoptosis, we investigated the role of the pro-survival members Bcl-2, Bcl-x(L) and Bcl-w in cancer development in p53(+/-) and p53(-/-) mice by testing whether ABT-737, a pharmacological inhibitor of these proteins, could prevent or delay tumourigenesis. Our studies showed that ABT-737 prophylaxis only caused a minor delay and reduction in γ-radiation-induced thymic lymphoma development in p53(-/-) mice, but this was accompanied by a concomitant increase in sarcoma. These data show that, collectively, Bcl-2, Bcl-x(L) and Bcl-w have only minor roles in thymic lymphoma development elicited by defects in p53, and this may indicate that Mcl-1 and/or A1 may feature more prominently in this process.

[Metformin effect on urethane-induced tumorigenesis in mice].

Sixty one male 129/Sv mice were exposed to a single intraperitoneal injection of 1 g per kilo of urethane dissolved in 0.9% normal saline. Starting the next day from the injection the study group mice were given 1200 mg metformin per liter of drinking water 5 days a week for 26 weeks. The control group mice received pure drinking water. Six months after the urethane treatment the mice were killed and the morphology samples were taken. Twenty five of 31 (96.7%) control group mice developed tumors (lung adenomas and thymic lymphomas), while tumor development was observed in 25 of 31 (80.7%; p<0.05) mice exposed to metformin. Solid or trabecular lung adenomas developed in 90% of the control group mice and in 77% of the metformin group mice (p=0.119). Therefore, it is a first evidence of tumor-inhibitory effect of metformin in mice.

Hydrogen protects mice from radiation induced thymic lymphoma in BALB/c mice.

Ionizing radiation (IR) is a well-known carcinogen, however the mechanism of radiation induced thymic lymphoma is not well known. Moreover, an easy and effective method to protect mice from radiation induced thymic lymphoma is still unknown. Hydrogen, or H(2), is seldom regarded as an important agent in medical usage, especially as a therapeutic gas. Here in this study, we found that H(2) protects mice from radiation induced thymic lymphoma in BALB/c mice.

Long-lasting antitumor protection by anti-CD20 antibody through cellular immune response.

The anti-CD20 monoclonal antibody (mAb) rituximab has been used successfully for lymphoma therapy for more than 10 years. Although several direct mechanisms by which anti-CD20 mAbs act have been characterized in vitro, their specific role in clinical efficacy is still debated. Little is known about the possible antitumor immune response that they may induce in patients, despite clinical data suggesting a "vaccinal" effect. We show here that an initial treatment with anti-CD20 induces protection against human CD20-expressing tumor cells and allows immunocompetent mice to survive tumor challenge. This long-lasting protection requires the presence of the Fc portion of the anti-CD20 mAb and is achieved through the induction of a cellular immune response. Only CD4(+) cells were needed at the beginning of the treatment, but both CD4(+) and CD8(+) cells were required after tumor challenge to achieve protection. Finally, we show that interleukin-2 treatment, given after tumor challenge, improves the overall survival rate, compared with that obtained by anti-CD20 treatment alone. These findings demonstrate that anti-CD20 mAbs exert therapeutic effects through the induction of an adaptive cellular immune response, aside from any direct mechanisms involving effectors from innate immunity.

Notch2 signaling is required for potent antitumor immunity in vivo.

CD8(+) T cells play a central role in cancer immunosurveillance, and the efficient induction of CTLs against tumor Ags is required for successful immunotherapy for cancer patients. Notch signaling directly regulates the transcription of effector molecules in CTLs. However, it remains unclear whether Notch signaling in CD8(+) T cells is required for antitumor CTL responses and whether modulation of Notch signaling can augment antitumor CTL responses. In this study, we demonstrate that signaling by Notch2 but not Notch1 in CD8(+) T cells is required for antitumor CTL responses. Notch2(flox/flox) mice crossed with E8I-cre transgenic (N2F/F-E8I) mice, in which the Notch2 gene is absent only in CD8(+) T cells, die earlier than control mice after inoculation with OVA-expressing EG7 thymoma cells. In contrast, Notch1(flox/flox) mice crossed with E8I-cre transgenic mice inoculated with EG7 cells die comparable to control mice, indicating that Notch2 is crucial for exerting antitumor CTL responses. Injection of anti-Notch2 agonistic Ab or delta-like 1-overexpressing dendritic cells augmented the antitumor response in C57BL/6 mice inoculated with EG7 cells. These findings indicate that Notch2 signaling in CD8(+) T cells is required for generating potent antitumor CTLs, thus providing a crucial target for augmenting tumor immune responses.

Induction of protective cytotoxic T-cell responses by a B-cell-based cellular vaccine requires stable expression of antigen.

B-cell-based cellular vaccines represent a promising approach to active immunotherapy of cancer complementing the use of dendritic cells, especially in pediatric patients and patients with low bone marrow reserves. B cells can be easily prepared in large numbers and readily home to secondary lymphoid organs, the primary site of induction of cytotoxic T lymphocyte (CTL) responses. However, most B-cell-based vaccines tested so far failed to induce functional and protective CTLs in in vivo models. Here, we show that B-cells activated through the toll-like receptor-9 (TLR-9) and CD40 up-regulate surface expression of major histocompatibility complex and costimulatory molecules, produce IL-12, and exhibit potent antigen-presenting properties in vitro. Importantly, although administration of peptide-coated or transiently transfected B cells fails to induce immune responses, therapeutic immunization with low numbers of genetically modified B cells stably expressing antigen results in an induction of functional CTLs and protection against the growth of tumor in an animal model. After activation, B cells partially loose their ability to home to organized lymphoid tissue because of the shedding of CD62L; however, this property can be restored by expression of protease-resistant mutant of CD62L. In summary, the data presented in this report suggest that genetically modified activated B cells represent a promising candidate for a cancer vaccine eliciting functional systemic CTLs.

Growth hormone supplementation increased latency to tumourigenesis in Atm-deficient mice.

Growth hormone (GH) is important for cell growth and differentiation, has multiple effects on lymphoid tissue and may promote blast cell proliferation and cancer development. We studied the effect of GH on longevity and tumour formation in Atm-deficient mice, an established model of the human cancer prone syndrome ataxia telangiectasia (AT). AT is a devastating recessive disorder that is characterized by progressive cerebellar ataxia, immunodeficiency, chromosomal instability and cancer susceptibility. Since AT patients also show endocrinological abnormalities the question has been raised as to whether GH therapy could be beneficial and/or increase the cancer risk in AT. We found that treatment with GH significantly increased longevity of Atm-deficient mice. In addition, GH ameliorated locomotoric behaviour and improved T-cell immunity. Thus, our data demonstrated that GH treatment is not necessarily accompanied by increased cancer development in diseases with chromosomal instability and cancer susceptibility and might be beneficial for AT patients.

Oligomannose-coated liposomes as a therapeutic antigen-delivery and an adjuvant vehicle for induction of in vivo tumor immunity.

In the present study, the adjuvant capacity of oligomannose-coated liposomes (OMLs) was evaluated in mice, and an OML-based vaccine was shown to induce effective anti-tumor immunity. C57BL/6 mice were immunized subcutaneously with OML-encased ovalbumin (OVA) and challenged with OVA-expressing E.G7-OVA tumor cells. All mice that received OVA in OMLs completely rejected the E.G7-OVA tumor. Spleen cells from the immunized mice showed strong cytotoxic activity against E.G7-OVA cells, but not against the parental EL4 cells. The therapeutic efficacy of OML-encased OVA against established E.G7-OVA tumors was then investigated. When the tumor mass became palpable (8-10 mm in length), the mice were treated with a single injection of 1 microg of OML-encased OVA. Tumor growth was reduced significantly in mice treated with OML-encased OVA and tumors were completely eliminated in about 40% of these mice. Similar results were obtained using EL4 tumors, with the EL4 cell lysate used as an antigen. These results indicate that an OML-based vaccine with an encased tumor antigen might be useful clinically to raise an effective immune response against a tumor.

Radiation-induced incidence of thymic lymphoma in mice and its prevention by antioxidants.

Previous reports from our laboratory have shown that in Swiss female mice exposed to an acute dose (3 Gy) of whole body irradiation (WBI), induced thymic lymphoma (TL) resulted after three to four weeks of exposure. The present study was aimed to further evaluate dependency on gender and effect of age of mice at the time of irradiation on TL incidence. A significant decrease in body weight gain was observed in female mice exposed to WBI, which was found to be correlated with the increase in weight and size of thymus, compared to their respective controls. An increase in TL incidence was observed with the increased postirradiation time, which was 47, 80, and 93% after 90, 120, and 150 days of WBI, respectively, in female mice. In irradiated female mice, the TL incidence was significantly higher and the growth of tumor in terms of weight and size was more aggressive than in males of the same age. Moreover, mice with higher age groups at the time of irradiation showed substantial decrease in TL incidence and its aggressiveness; and these effects were more conspicuous in males than in females. In mice irradiated at the age group of three to four weeks, the TL incidence was 83 and 72% in female and male, respectively, which was decreased to 74% in female and 14% in male in the age group of 12-13 weeks. It was further observed that the postirradiation feeding of animals with antioxidants resulted in a significant decrease in TL incidence, and the prevention in TL incidence was more in animals fed with curcumin (55%) than with ascorbic acid and eugenol (20%). These results have provided significant new findings on the phenomenon of radiation-induced TL incidence related to gender and age at the time of irradiation and its prevention by postirradiation antioxidant feeding to mice.