A co-formulation of interferons alpha2b and gamma distinctively targets cell cycle in the glioblastoma-derived cell line U-87MG

BACKGROUND

HeberFERON is a co-formulation of α2b and γ interferons, based on their synergism, which has shown its clinical superiority over individual interferons in basal cell carcinomas. In glioblastoma (GBM), HeberFERON has displayed promising preclinical and clinical results. This led us to design a microarray experiment aimed at identifying the molecular mechanisms involved in the distinctive effect of HeberFERON compared to the individual interferons in U-87MG model.

METHODS

Transcriptional expression profiling including a control (untreated) and three groups receiving α2b-interferon, γ-interferon and HeberFERON was performed using an Illumina HT-12 microarray platform. Unsupervised methods for gene and sample grouping, identification of differentially expressed genes, functional enrichment and network analysis computational biology methods were applied to identify distinctive transcription patterns of HeberFERON. Validation of most representative genes was performed by qPCR. For the cell cycle analysis of cells treated with HeberFERON for 24 h, 48 and 72 h we used flow cytometry.

RESULTS

The three treatments show different behavior based on the gene expression profiles. The enrichment analysis identified several mitotic cell cycle related events, in particular from prometaphase to anaphase, which are exclusively targeted by HeberFERON. The FOXM1 transcription factor network that is involved in several cell cycle phases and is highly expressed in GBMs, is significantly down regulated. Flow cytometry experiments corroborated the action of HeberFERON on the cell cycle in a dose and time dependent manner with a clear cellular arrest as of 24 h post-treatment. Despite the fact that p53 was not down-regulated, several genes involved in its regulatory activity were functionally enriched. Network analysis also revealed a strong relationship of p53 with genes targeted by HeberFERON. We propose a mechanistic model to explain this distinctive action, based on the simultaneous activation of PKR and ATF3, p53 phosphorylation changes, as well as its reduced MDM2 mediated ubiquitination and export from the nucleus to the cytoplasm. PLK1, AURKB, BIRC5 and CCNB1 genes, all regulated by FOXM1, also play central roles in this model. These and other interactions could explain a G2/M arrest and the effect of HeberFERON on the proliferation of U-87MG.

CONCLUSIONS

We proposed molecular mechanisms underlying the distinctive behavior of HeberFERON compared to the treatments with the individual interferons in U-87MG model, where cell cycle related events were highly relevant.

Gene expression profiling unveils the temporal dynamics of CIGB-300-regulated transcriptome in AML cell lines

BACKGROUND

Protein kinase CK2 activity is implicated in the pathogenesis of various hematological malignancies like Acute Myeloid Leukemia (AML) that remains challenging concerning treatment. This kinase has emerged as an attractive molecular target in therapeutic. Antitumoral peptide CIGB-300 blocks CK2 phospho-acceptor sites on their substrates but it also binds to CK2α catalytic subunit. Previous proteomic and phosphoproteomic experiments showed molecular and cellular processes with relevance for the peptide action in diverse AML backgrounds but earlier transcriptional level events might also support the CIGB-300 anti-leukemic effect. Here we used a Clariom S HT assay for gene expression profiling to study the molecular events supporting the anti-leukemic effect of CIGB-300 peptide on HL-60 and OCI-AML3 cell lines.

RESULTS

We found 183 and 802 genes appeared significantly modulated in HL-60 cells at 30 min and 3 h of incubation with CIGB-300 for p < 0.01 and FC >  = │1.5│, respectively; while 221 and 332 genes appeared modulated in OCI-AML3 cells. Importantly, functional enrichment analysis evidenced that genes and transcription factors related to apoptosis, cell cycle, leukocyte differentiation, signaling by cytokines/interleukins, and NF-kB, TNF signaling pathways were significantly represented in AML cells transcriptomic profiles. The influence of CIGB-300 on these biological processes and pathways is dependent on the cellular background, in the first place, and treatment duration. Of note, the impact of the peptide on NF-kB signaling was corroborated by the quantification of selected NF-kB target genes, as well as the measurement of p50 binding activity and soluble TNF-α induction. Quantification of CSF1/M-CSF and CDKN1A/P21 by qPCR supports peptide effects on differentiation and cell cycle.

CONCLUSIONS

We explored for the first time the temporal dynamics of the gene expression profile regulated by CIGB-300 which, along with the antiproliferative mechanism, can stimulate immune responses by increasing immunomodulatory cytokines. We provided fresh molecular clues concerning the antiproliferative effect of CIGB-300 in two relevant AML backgrounds.

Active immunization with a structurally aggregated PD-L1 antigen breaks T and B immune tolerance in non-human primates and exhibits in vivo anti-tumoral effects in immunocompetent mouse tumor models

Despite the clinical success of the programmed death ligand 1 (PD-L1) blocking therapy in cancer treatment, only a subset of patients exhibits durable responses, therefore further exploration of other immunotherapeutic alternatives are needed. This paper reported the development of the PKPD-L1^Vac vaccine, a new protein vaccine candidate that uses aluminum phosphate as an adjuvant and as an antigen the extracellular domain of human PD-L1 fused to a 47 amino-terminal portion of the LpdA protein from N. meningitides (PKPD-L1). The PKPD-L1 antigen has different physical and biological characteristics than those found in the natural molecule and in others PD-L1 vaccine candidates. The quimeric protein has a reduced binding capacity to the PD-1 and CD80 receptors to decrease their pro-tumoral activity. Besides, the distinctive feature of the PKPD-L1 polypeptide to be structurally aggregated could be desirable for its immunogenic properties. PKPD-L1^Vac elicited anti-PD-L1-specific IgG antibodies and T lymphocyte-mediated immunity in mice and non-human primates. The vaccine administration demonstrated antitumor activity on CT-26 and B16-F10 primary tumor models in mice. Moreover, the immunization with PKPD-L1^Vac increased the tumor-infiltrating lymphocytes and decreased the proportion of CD3⁺CD8⁺PD1^+high anergic T cells in CT-26 tumor tissues, suggesting that the vaccine may remodel the tumor microenvironment. In summary, the PKPD-L1^Vac vaccine exhibits very promising preclinical results and deserves to move forward to a phase I clinical trial.

Comparative study of the immunogenicity and immunoenhancing effects of two hepatitis B core antigen variants in mice by nasal administration

The hepatitis B virus (HBV) core antigen (HBcAg) is a potent immunogen in animal models and humans and has been used as a carrier for several antigens; however, the mucosal immunogenicity of HBcAg has been poorly studied. In this study, we explored the immunogenicity and the immunoenhancing effect elicited by two different variants of the recombinant complete nucleocapside of HBV in mice by intranasal route. For this purpose, we used as co-administered antigen, the HBV surface protein (HBsAg) and the antibody response in sera was evaluated after each dose. To analyze the specificity of the generated antibody response, the recognition of lineal epitopes was evaluated on a cellulose membrane bearing 12 mer peptides covering the HBcAg sequence. The obtained results evidenced that the intranasal immunogenicity of both variants of HBcAg was similar and high, developing early responses of IgG. The immunoenhancing effect on the HBsAg-specific antibody response was also similar for both variants. The results of the recognition of lineal epitopes study evidenced a similar recognition pattern to all sera and vaginal lavages samples generated by the immunization of mice with the two variants of HBcAg, and also similar to a pool of human anti-HBcAg positive sera samples.

Immunological characterization of two hepatitis B core antigen variants and their immunoenhancing effect on co-delivered hepatitis B surface antigen

The hepatitis B virus (HBV) core and surface antigens are potent immunogens in animal models and humans. They have been used in vaccine studies for prevention or therapy of HBV diseases and also as carrier molecules in new developments. In this study we explored the nasal immunogenicity of two different variants of the recombinant complete nucleocapsid (HBcAg) as well as their adjuvant effect on hepatitis B surface antigen (HBsAg). To characterize the immune response, the serum IgG antibody response was tested during one year against both antigens, and the serum and vaginal secretions were tested for recognition of linear epitopes of HBcAg for both HBcAg variants. The results obtained evidenced that the intranasal immunogenicity of both HBcAg variants was similar and high, developing early and long lasting IgG responses. A similar recognition pattern to all sera and vaginal washes samples was generated by the two variants of HBcAg, also similar to a pool of human anti-HBcAg positive sera. A synergistic effect in the enhancement of the immunogenicity for both antigens was evidenced in the combined formulation after nasal administration. Taken together, these results would be of interest in the design of more potent therapeutic and preventive vaccines complementing systemic and mucosal responses.

Diagnosis of dengue virus infection by the visual and simple AuBioDOT immunoglobulin M capture system

The Dengue IgM Capture ELISA (MAC-ELISA) is the immunoenzymatic system recommended by the Pan American Health Organization and the World Health Organization for the serological diagnosis of dengue virus infection due to its high sensitivity, ease of performance, and use of a single acute-phase serum sample. However, tests with this enzyme-linked immunosorbent assay (ELISA) system are time-consuming and require equipment for washing, incubation, and reading of the results. AuBioDOT is a multistep visual diagnostic immunoassay that uses technology based on the immunoglobulin M (IgM) capture ELISA principle. This system uses white polyethylene opaque plates as the solid phase, colloidal gold as the marker, and silver ion amplification. It does not require special equipment, it is totally manually operated, and it can be performed in less than 1 h. The sensitivity and specificity of AuBioDOT for the detection of anti-dengue virus IgM antibodies were studied with a panel of 336 serum samples (150 serum samples from patients with suspected or serologically confirmed dengue virus infection, 186 serum samples from healthy blood donors and patients without dengue virus infection). The results were compared with those obtained by the MAC-ELISA. A sensitivity of 97.7% and a specificity of 97.1% were obtained. The concordance of the two tests was 97.3%, with a kappa index of 0.94. The application of AuBioDOT for the detection of anti-dengue virus IgM antibodies is recommended as an alternative method for the diagnosis of dengue virus infection, both for clinical diagnosis and for seroepidemiological surveillance. The system is useful under field conditions and in laboratories and requires little equipment.

Expression of a single-chain Fv antibody fragment specific for the hepatitis B surface antigen in transgenic tobacco plants

An anti-Hepatitis B virus surface antigen (HBsAg) single chain Fv (scFv) antibody fragment was expressed in Nicotiana tabacum transgenic plants. The 6-histidine tagged scFv was targeted to either the cytosol, apoplast, and vacuole, or for retention in the endoplasmic reticulum. Expression of active scFv was detected by ELISA in fresh leaf material from F I transgenic plant lines representative of the genetic constructs targeting the antibody fragment to the apoplastic fluid (AF-12, 0.031% of the total soluble protein), vacuole (V-20, 0.032% of the total soluble protein), and endoplasmic reticulum (ER-52, 0.22% of the total soluble protein). No scFv was detected by ELISA or western blot in the plants transformed with the cytosol construct. The biologically active scFv was easily purified (to 94-95% purity) from ER-52 and AF-12 plant material using immobilized metal ion affinity chromatography. Recovery estimated from the ER-52 plant line indicates that 15-20 microg of pure active scFv can be obtained per gram of fresh leaf material, on a laboratory scale.

A recombinant protein based immunoassay for the combined detection of antibodies to HIV-1, HIV-2 and HTLV-I

The aim of this study was to develop and evaluate a combined assay for the detection of antibodies to HIV-1, HIV-2 and HTLV-I (human T-cell leukemia virus type I). A mixture of recombinant proteins and synthetic peptides was fixed to the surface of microELISA wells and a protein A peroxidase conjugate was used as tracer. The combined assay was compared to specific HIV-1/2 and HTLV-I commercial ELISAs. The sensitivity was studied with a panel of 158 HIV-1, 82 HIV-2 and 48 HTLV-I positive sera, all of which were reactive in the combined assay. The analytical sensitivity was studied with a panel of serially diluted sera and was similar to that obtained for the specific ELISAs. The specificity of the test was 99.78% against a panel of 466 negative sera collected from voluntary donors that included HBsAg, HCV, and VDRL positive sera. The false positive serum was borderline in the HTLV-I specific ELISA. The new combined ELISA can be used as an efficient initial screening assay, avoiding the cost of individual tests for HIV and HTLV.