In silico enhancer mining reveals SNS-032 and EHMT2 inhibitors as therapeutic candidates in high-grade serous ovarian cancer.

BACKGROUND: Epigenomic dysregulation has been linked to solid tumour malignancies, including ovarian cancers. Profiling of re-programmed enhancer locations associated with disease has the potential to improve stratification and thus therapeutic choices. Ovarian cancers are subdivided into histological subtypes that have significant molecular and clinical differences, with high-grade serous carcinoma representing the most common and aggressive subtype. METHODS: We interrogated the enhancer landscape(s) of normal ovary and subtype-specific ovarian cancer states using publicly available data. With an initial focus on H3K27ac histone mark, we developed a computational pipeline to predict drug compound activity based on epigenomic stratification. Lastly, we substantiated our predictions in vitro using patient-derived clinical samples and cell lines. RESULTS: Using our in silico approach, we highlighted recurrent and privative enhancer landscapes and identified the differential enrichment of a total of 164 transcription factors involved in 201 protein complexes across the subtypes. We pinpointed SNS-032 and EHMT2 inhibitors BIX-01294 and UNC0646 as therapeutic candidates in high-grade serous carcinoma, as well as probed the efficacy of specific inhibitors in vitro. CONCLUSION: Here, we report the first attempt to exploit ovarian cancer epigenomic landscapes for drug discovery. This computational pipeline holds enormous potential for translating epigenomic profiling into therapeutic leads.

Histone-lysine N-methyltransferase EHMT2 (G9a) inhibition mitigates tumorigenicity in Myc-driven liver cancer.

Hepatocellular carcinoma (HCC) is the third deadliest and sixth most common cancer in the world. Histone-lysine N-methyltransferase EHMT2 (also known as G9a) is a histone methyltransferase frequently overexpressed in many cancer types, including HCC. We showed that Myc-driven liver tumours have a unique H3K9 methylation pattern with corresponding G9a overexpression. This phenomenon of increased G9a was further observed in our c-Myc-positive HCC patient-derived xenografts. More importantly, we showed that HCC patients with higher c-Myc and G9a expression levels portend a poorer survival with lower median survival months. We demonstrated that c-Myc interacts with G9a in HCC and cooperates to regulate c-Myc-dependent gene repression. In addition, G9a stabilises c-Myc to promote cancer development, contributing to the growth and invasive capacity in HCC. Furthermore, combination therapy between G9a and synthetic-lethal target of c-Myc, CDK9, demonstrates strong efficacy in patient-derived avatars of Myc-driven HCC. Our work suggests that targeting G9a could prove to be a potential therapeutic avenue for Myc-driven liver cancer. This will increase our understanding of the underlying epigenetic mechanisms of aggressive tumour initiation and lead to improved therapeutic and diagnostic options for Myc-driven hepatic tumours.

The human leukocyte antigen as a candidate tumor suppressor.

Here we argue in support of the human leukocyte antigen (HLA) supergene as a tumor suppressor. HLA is a recurring mutational target in a large and diverse group of malignancies. The tumor suppressor function of HLA is linked to an embryonic/stemness and drug resistance phenotype. A deeper understanding of the distinct roles of HLA, including immunosurveillance, stemness, and tumor suppressor functions, could illuminate the limited responses in cancer patients. Furthermore, it would provide guidelines for the design of new therapeutic strategies, including the potential of modulating HLA expression in the tumor stem cell compartment.

Polimorfismo de los antígenos leucocitarios humanos en receptores cubanos de trasplante relacionado de progenitores hematopoyéticas / Polymorphism of human leukocyte antigens in Cuban recipients of related hematopoietic stem cell transplants

Introducción: El trasplante relacionado de células progenitoras hematopoyéticas (TCPH) es una alternativa terapéutica curativa para los pacientes con ciertos tipos de hemopatías o de inmunodeficiencias, en la que se selecciona como donante a un familiar del receptor. Objetivo: Caracterizar el sistema de antígenos leucocitarios humanos (HLA) en receptores de TCPH relacionado. Métodos: Se realizó un estudio descriptivo y transversal en el departamento de Histocompatibilidad del Instituto de Hematología e Inmunología desde enero 2013 hasta diciembre de 2015. Se tipificaron 75 genes HLA mediante la técnica de reacción en cadena de la polimerasa con cebadores de secuencia específico, de baja resolución a 117 pacientes con criterio de TCPH. Para el análisis inmunogenético se empleó el programa Arlequín 3.5.2.2. Resultados: Fueron más frecuentes los genes HLA-A*02, HLA-B*35, HLA-DQB1*03, HLA-DRB1*03 y HLA-DRB1*04, los haplotipos de dos loci HLA-A*02 B*35, HLA-DQB1*03 DRB1*04 y el haplotipo extendido HLA-A*03 B*07 DQB1*06 DRB1*15. Conclusiones: Los genes del sistema HLA en pacientes cubanos candidatos a TCPH relacionado presentaron frecuencias similares a las descritas en poblaciones generales de Cuba y el mundo, aunque con características distintivas en algunos genes y haplotipos(AU)

Introduction: Related hematopoietic progenitor cell (TCPH) transplantation is a curative therapeutic alternative for patients with certain types of hemopathies or immunodeficiencies, in which a recipient family member is selected as a donor. Objective: To characterize the human leukocyte antigen (HLA) system in related TCPH receptors. Methods: A descriptive and cross-sectional study was conducted in the Histocompatibility department of the Institute of Hematology and Immunology from January 2013 to December 2015. 75 HLA genes were typed using the polymerase chain reaction technique with specific sequence primers, from Low resolution to 117 patients with TCPH criteria. For the immunogenetic analysis, the Harlequin 3.5.2.2 program was used. Results: The genes HLA-A * 02, HLA-B * 35, HLA-DQB1 * 03, HLA-DRB1 * 03 and HLA-DRB1 * 04, the haplotypes of two HLA-A * 02 B * 35 loci were more frequent , HLA-DQB1 * 03 DRB1 * 04 and the extended haplotype HLA-A * 03 B * 07 DQB1 * 06 DRB1 * 15. Conclusions: The genes of the HLA system in Cuban patients related to TCPH presented frequencies similar to those described in general populations of Cuba and the world, although with distinctive characteristics in some genes and haplotypes(AU)

C4BP-IgM protein as a therapeutic approach to treat Neisseria gonorrhoeae infections.

Gonorrhea is a sexually transmitted infection with 87 million new cases per year globally. Increasing antibiotic resistance has severely limited treatment options. A mechanism that Neisseria gonorrhoeae uses to evade complement attack is binding of the complement inhibitor C4b-binding protein (C4BP). We screened 107 porin B1a (PorB1a) and 83 PorB1b clinical isolates randomly selected from a Swedish strain collection over the last 10 years and noted that 96/107 (89.7%) PorB1a and 16/83 (19.3%) PorB1b bound C4BP; C4BP binding substantially correlated with the ability to evade complement-dependent killing (r = 0.78). We designed 2 chimeric proteins that fused C4BP domains to the backbone of IgG or IgM (C4BP-IgG; C4BP-IgM) with the aim of enhancing complement activation and killing of gonococci. Both proteins bound gonococci (KD C4BP-IgM = 2.4 nM; KD C4BP-IgG 980.7 nM), but only hexameric C4BP-IgM efficiently outcompeted heptameric C4BP from the bacterial surface, resulting in enhanced complement deposition and bacterial killing. Furthermore, C4BP-IgM substantially attenuated the duration and burden of colonization of 2 C4BP-binding gonococcal isolates but not a non-C4BP-binding strain in a mouse vaginal colonization model using human factor H/C4BP-transgenic mice. Our preclinical data present C4BP-IgM as an adjunct to conventional antimicrobials for the treatment of gonorrhea.

The use of peptide-major-histocompatibility-complex multimers in type 1 diabetes mellitus.

Major histocompatibility complex (MHC) class I and MHC class II molecules present short peptides that are derived from endogenous and exogenous proteins, respectively, to cognate T-cell receptors (TCRs) on the surface of T cells. The exquisite specificity with which T cells recognize particular peptide-major-histocompatibility-complex (pMHC) combinations has permitted development of soluble pMHC multimers that bind exclusively to selected T-cell populations. Because the pathogenesis of type 1 diabetes mellitus (T1DM) is driven largely by islet-reactive T-cell activity that causes ß-cell death, these reagents are useful tools for studying and, potentially, for treating this disease. When coupled to fluorophores or paramagnetic nanoparticles, pMHC multimers have been used to visualize the expansion and islet invasion of T-cell effectors during diabetogenesis. Administration of pMHC multimers to mice has been shown to modulate T-cell responses by signaling through the TCR or by delivering a toxic moiety that deletes the targeted T cell. In the nonobese diabetic mouse model of T1DM, a pMHC-I tetramer coupled to a potent ribosome-inactivating toxin caused long-term elimination of a specific diabetogenic cluster of differentiation 8+ T-cell population from the pancreatic islets and delayed the onset of diabetes. This review will provide an overview of the development and use of pMHC multimers, particularly in T1DM, and describe the therapeutic promise these reagents have as an antigen-specific means of ameliorating deleterious T-cell responses in this autoimmune disease.

Tumor vaccination that enhances antitumor T-cell responses does not inhibit the growth of established tumors even in combination with interleukin-12 treatment: the importance of inducing intratumoral T-cell migration.

Interleukin-12 (IL-12) treatment is effective in the CSA1M but not in the Meth A and CSA1M-variant tumor models. The authors investigated the cause by which IL-12 treatment fails to induce tumor regression in these two tumor models. T cells from CSA1M-bearing mice have high levels of IL-12 responsiveness, whereas cells from Meth A-bearing mice display marginal levels of responsiveness. Because IL-12 responsiveness in T cells is induced after T-cell receptor stimulation, the lack of IL-12 responsiveness suggests that T cells in Meth A-bearing mice are not sensitized to Meth A tumor antigen. Immunization of normal mice with attenuated Meth A tumor cells resulted in a protective immunity, as shown by the rejection of challenged viable Meth A cells. Such an immunization, when performed in Meth A-bearing mice, induced potent IL-12 responsiveness in T cells. Nevertheless, IL-12 treatment in these mice did not inhibit tumor growth. In another IL-12-incurable (CSA1M-variant) model, IL-12 responsiveness was observed before tumor cell immunization. However, IL-12 treatment was ineffective regardless of whether tumor cell immunization was performed. In these two models, the failure of IL-12 treatment to induce tumor regression was associated with the lack of T-cell migration to tumor sites. These results indicate that the sensitization of T cells to tumor antigens and generation of IL-12 responsiveness are insufficient to induce tumor regression when these sensitized T cells are not allowed to migrate to tumor sites.

Prolongation of porcine islet xenograft survival in mice after therapy with immunosuppressive peptides.

BACKGROUND: Recently, peptides derived from the heavy chain of HLA-B2702 have been shown to modulate immune responses. In this study, we examined the use of these peptides for immunosuppression in a pig to mouse islet xenograft model. METHODS: Purified porcine islets were transplanted in autoimmune (non-obese diabetic) and non-autoimmune (streptozotocin-injected CBA or C57/Bl6) diabetic mice. Various dosing regimens of HLA-derived peptides with and without antilymphocyte therapy were administered to recipient mice. Graft rejection was determined by daily serum glucose determinations, and, at selected time points, grafts were removed to demonstrate function and provide immunohistochemical examination. RESULTS: HLA-derived peptides were demonstrated to prolong graft survival in both pretransplant and posttransplant treatment regimens. This effect was increased with concomitant antilymphocyte therapy. CONCLUSIONS: Further elucidation of the mechanism of action of these immunomodulatory peptides may help in the development of novel immunosuppressive protocols.

Reversal of acute experimental autoimmune encephalomyelitis and prevention of relapses by treatment with a myelin basic protein peptide analogue modified to form long-lived peptide-MHC complexes.

Experimental autoimmune encephalomyelitis (EAE) is an autoimmune disease induced by immunization with myelin basic protein (MBP), proteolipid protein, or encephalitogenic peptides from these myelin components. EAE resembles basic protein multiple sclerosis in some of its clinical and histologic features, and serves as an experimental model for this and other autoimmune diseases. In this study, we examine i.v. peptide therapy of EAE in detail, and show that repeated i.v. injections of MBP peptides effectively treat EAE in (PLJxSJL)F1 mice. In this study, administration of the immunodominant epitope (MBP Ac1-11) prevents MBP-induced disease, whereas the subdominant epitope MBP 31-47 is neither required nor sufficient. Intravenous administration of substituted MBP peptide analogues is also effective in treating EAE, provided the peptide side chains presumed to be involved in TCR contact and MHC binding are preserved. A substituted MBP peptide analogue that forms long-lived peptide-MHC complexes in vivo is more effective than the unmodified MBP peptide. Lower doses of the substituted peptide analogue are effective, and the effect is longer lasting than treatment with the unmodified peptide. Clinical signs of EAE are reversed by injection of the substituted peptide during the acute phase of disease. Moreover, treatment of mice in the remission phase of EAE results in a dramatically reduced incidence of relapse. In summary, we have shown that EAE can be reversed after onset and treated during remission with an MBP peptide analogue that has been modified for improved therapeutic potency.

Symposium Trasplante de órganos en México: Inmunología de trasplantes / Trasplantation Immunology

En el presente artículo se revisan brevemente los antecedentes históricos trascendentales de la inmunología de los trasplantes de órganos. Se describen los aspectos fundamentales de la tipificación del sistema HLA y la clasificación de sus antígenos en clase, I, II y III. También se discuten los hechos más relevantes en relación con el cultivo de mezcla de linfocitos y la importancia de la pre-sensibilización a antígenos de histocompatibilidad

[Specific active immunotherapy of murine methylcholanthrene-induced sarcoma using a partially purified soluble tumor specific transplantation antigens].

Immunotherapeutic effects of soluble tumor specific transplantation antigens (TSTA) were studied, Crude 3M KC1 extract of C3H/He methylcholanthrene-induced sarcoma (F tumor) was purified by preparative isoelectric focusing (pIEF). The immunoprotective fraction (Fr. 15, pI 5.7-6.0) possessed about 50 fold greater activity than the crude 3M KC1 extract. Three weekly injections of optimal immunoprotective dose of Fr. 15 retarded the outgrowth of F cells and decreased the outgrowth and tumor incidence of rechallenged inoculation in mice completely resected established 1 cm tumor. Weekly injections of Fr. 15 resulted in decreased local recurrences. This therapeutic effect was immunologically specific. Fr. 15 alone did not show the therapeutic effects on the established tumor, but combined treatment with cyclophosphamide gave the increased survivals. A metastatic variant cell line (F-4) metastasized to the lung spontaneously after the resection of primary subcutaneous tumor. Therapeutic injections of Fr. 15 decreased the rates of spontaneous pulmonary metastasis of F-4. Since cross-immunoprotection tests revealed that F and F-4 share the common TSTA, the therapeutic effect of Fr. 15 upon pulmonary metastases might be due to improved host's specific immunity.