Fluorescent nanohybrids based on quantum dot-chitosan-antibody as potential cancer biomarkers.

Despite undeniable advances in medicine in recent decades, cancer is still one of the main challenges faced by scientists and professionals in the health sciences as it remains one of the world's most devastating diseases with millions of fatalities and new cases every year. Thus, in this work, we endeavored to synthesize and characterize novel multifunctional immunoconjugates composed of quantum dots (QDs) as the fluorescent inorganic core and antibody-modified polysaccharide as the organic shell, focusing on their potential applications for in vitro diagnosis of non-Hodgkin lymphoma (NHL) cancer tumors. Chitosan was covalently conjugated with anti-CD20 polyclonal antibody (pAbCD20) via formation of amide bonds between amines and carboxyl groups. In the sequence, these biopolymer-antibody immunoconjugates were utilized as direct capping ligands for biofunctionalization of CdS QDs (CdS/chitosan-pAbCD20) using a single-step process in aqueous medium at room temperature. The nanostructures were characterized by UV-vis spectroscopy, photoluminescence spectroscopy (PL), FTIR, and transmission electron microscopy (TEM) with selected area electron diffraction. The TEM images associated with the UV-vis optical absorption results indicated formation of ultrasmall nanocrystals with average diameters in the range of 2.5-3.0 nm. Also, the PL results demonstrated that the immunoconjugates exhibited "green" fluorescent activity under ultraviolet excitation. Moreover, using in vitro laser light scattering immunoassay (LIA), the QDs/immunoconjugates have shown binding affinity against antigen CD20 (aCD20) expressed by lymphocyte-B cancer cells. In summary, innovative fluorescent nanoimmunoconjugate templates were developed with promising perspectives to be used in the future for detection and imaging of cancer tumors.

Topical treatment of actinic keratosis with imiquimod 5% cream / Tratamento tópico de ceratose actínica com imiquimod creme 5%

The viability and the efficiency of imiquimod 5% cream in a cat which suffered from nasal actinic keratosis were evaluated. The procedures were carried out at home by the owners themselves. Six packets of the cream were used, one per week, in three consecutive daily applications, with a four-day interval (without treatment). The cytological results were negative for neoplastic cells 30 days after the end of the treatment. A clinical revision was conducted 18 months later and the animal showed no signs of recurrence. The cream proved to be safe and efficient. There are no reports regarding efficiency in animals concerning the treatment with imiquimod 5% cream and also regarding other effects related to this treatment. A case report presenting a positive response can reveal with terapeutical possibilities that it would be easily available and applicable for all professionals. In the future it would be a new alternative to avoid progressions of this kind of neoplasia which is often observed in the small animal clinic.

Avaliaram-se a viabilidade e a eficácia da utilização do imiquimod creme 5% em um gato portador de ceratose actínica nasal. As aplicações foram realizadas no domicílio, pelos proprietários, sendo utilizados seis sachês do creme, um por semana, em protocolo de três aplicações diárias consecutivas e quatro dias de descanso (sem tratamento). Após 30 dias do término do tratamento, obteve-se citologia negativa para células neoplásicas. Em revisão clínica 18 meses após o tratamento, o paciente apresentava-se sem sinais de recidiva. O protocolo mostrou-se seguro e eficaz. Em animais não há relatos sobre a eficácia da terapia com imiquimod, bem como sobre efeitos adversos decorrentes deste tratamento. A apresentação de um caso em que se observou resposta positiva pode descortinar uma nova possibilidade terapêutica, acessível a todo clínico, que poderá evitar a progressão destas neoplasias que são frequentemente observadas na clínica de pequenos animais.

ß-Actin-binding complementarity-determining region 2 of variable heavy chain from monoclonal antibody C7 induces apoptosis in several human tumor cells and is protective against metastatic melanoma.

Complementarity-determining regions (CDRs) from monoclonal antibodies tested as synthetic peptides display anti-infective and antitumor activities, independent of the specificity of the native antibody. Previously, we have shown that the synthetic peptide C7H2, based on the heavy chain CDR 2 from monoclonal antibody C7, a mAb directed to a mannoprotein of Candida albicans, significantly reduced B16F10 melanoma growth and lung colony formation by triggering tumor apoptosis. The mechanism, however, by which C7H2 induced apoptosis in tumor cells remained unknown. Here, we demonstrate that C7H2 interacts with components of the tumor cells cytoskeleton, being rapidly internalized after binding to the tumor cell surface. Mass spectrometry analysis and in vitro validation revealed that ß-actin is the receptor of C7H2 in the tumor cells. C7H2 induces ß-actin polymerization and F-actin stabilization, linked with abundant generation of superoxide anions and apoptosis. Major phenotypes following peptide binding were chromatin condensation, DNA fragmentation, annexin V binding, lamin disruption, caspase 8 and 3 activation, and organelle alterations. Finally, we evaluated the cytotoxic efficacy of C7H2 in a panel of human tumor cell lines. All tumor cell lines studied were equally susceptible to C7H2 in vitro. The C7H2 amide without further derivatization significantly reduced lung metastasis of mice endovenously challenged with B16F10-Nex2 melanoma cells. No significant cytotoxicity was observed toward nontumorigenic cell lines on short incubation in vitro or in naïve mice injected with a high dose of the peptide. We believe that C7H2 is a promising peptide to be developed as an anticancer drug.

Topical treatment of actinic keratosis with imiquimod 5% cream / Tratamento tópico de ceratose actínica com imiquimod creme 5%

The viability and the efficiency of imiquimod 5% cream in a cat which suffered from nasal actinic keratosis were evaluated. The procedures were carried out at home by the owners themselves. Six packets of the cream were used, one per week, in three consecutive daily applications, with a four-day interval (without treatment). The cytological results were negative for neoplastic cells 30 days after the end of the treatment. A clinical revision was conducted 18 months later and the animal showed no signs of recurrence. The cream proved to be safe and efficient. There are no reports regarding efficiency in animals concerning the treatment with imiquimod 5% cream and also regarding other effects related to this treatment. A case report presenting a positive response can reveal with terapeutical possibilities that it would be easily available and applicable for all professionals. In the future it would be a new alternative to avoid progressions of this kind of neoplasia which is often observed in the small animal clinic.(AU)

Avaliaram-se a viabilidade e a eficácia da utilização do imiquimod creme 5% em um gato portador de ceratose actínica nasal. As aplicações foram realizadas no domicílio, pelos proprietários, sendo utilizados seis sachês do creme, um por semana, em protocolo de três aplicações diárias consecutivas e quatro dias de descanso (sem tratamento). Após 30 dias do término do tratamento, obteve-se citologia negativa para células neoplásicas. Em revisão clínica 18 meses após o tratamento, o paciente apresentava-se sem sinais de recidiva. O protocolo mostrou-se seguro e eficaz. Em animais não há relatos sobre a eficácia da terapia com imiquimod, bem como sobre efeitos adversos decorrentes deste tratamento. A apresentação de um caso em que se observou resposta positiva pode descortinar uma nova possibilidade terapêutica, acessível a todo clínico, que poderá evitar a progressão destas neoplasias que são frequentemente observadas na clínica de pequenos animais.(AU)

Investigation of lymphocyte depletion and repopulation using alemtuzumab (Campath-1H) in cynomolgus monkeys.

As the target CD52 molecule is expressed on erythrocytes of most nonhuman primate strains, using alemtuzumab in these species would cause massive hemolysis. Six cynomolgus monkeys of Indonesian origin, screened by agglutination assay for absence of CD52 on erythrocytes, were administered alemtuzumab in a cumulative dose to a maximum of 60 mg/kg. In two monkeys, mycophenolate mofetil (MMF) was added as maintenance therapy. Complete depletion of T and B lymphocytes (>99.5%) was achieved with 20 mg/kg alemtuzumab and was more profound than in monkeys treated with antithymocyte globulin (n = 5), as quantified by flow cytometry. Repopulation was suppressed by weekly injections of 10 mg/kg. Without MMF, repopulation of CD20(+)B cells and CD8(+)T cells was complete within 2 and 3 months, respectively, and repopulation of CD4(+)T cells was 67% after 1 year. MMF significantly delayed CD4(+)T-cell repopulation. Among repopulating CD4(+) and CD8(+) T cells, a phenotypic shift was observed from CD45RA(hi)CD62L(hi) naïve cells toward CD45RA(lo)CD62L(lo) effector memory cells. In lymph nodes, the depletion of naïve cells was more profound than of memory cells, which may have initiated a proliferation of memory cells. This model offers opportunities to investigate lymphocyte depletion/repopulation phenomena, as well as the efficacy of alemtuzumab in preclinical transplantation models.

Targeting cancer stem cells with monoclonal antibodies: a new perspective in cancer therapy and diagnosis.

This review discusses some of the impacts that biotechnology, genomics and nanotechnology convergence should have on future cancer management, in particular, the development of innovative diagnostic and therapeutic approaches based on monoclonal antibodies (mAbs) and cancer stem cells. Emergent therapeutic strategies in cancer have been focusing on the use of mAbs to stimulate an immune response against tumors, to block signaling pathways, or to refine delivery of cytotoxic agents. Now that cancer stem cells are being identified and characterized in different tumor types, their relevance to cancer physiopathology is becoming evident, making them natural targets for mAb development. Cancer stem cells are postulated to be responsible for tumor development, metastasis and relapse after conventional therapies. Therefore, mAbs targeting specific antigens and related pathways altered in cancer stem cells should facilitate earlier diagnosis through molecular imaging techniques and more efficient destruction of tumor initiating cells, thus improving clinical outcome.

Antiproliferative, antiangiogenic and proapoptotic activity of h-R3: A humanized anti-EGFR antibody.

The epidermal growth factor receptor (EGFR) proto-oncogene is frequently overexpressed in tumors of epithelial origin. This event is thought to be causative for tumor development and progression and henceforth associated with poor prognosis. The recent considerable interest in developing EGFR-targeting agents resulted in derivation of the monoclonal, humanized, neutralizing antibody h-R3, which binds to the extracellular domain of EGFR with high affinity and strongly inhibits EGFR-dependent cellular transformation. Thus, treatment of A431 squamous cell carcinoma cells with h-R3 in either 2-dimensional or 3-dimensional culture resulted in appreciable antimitotic effects through induction of the G1 arrest. Although h-R3 does not appear to have a direct proapoptotic activity in this setting, it inhibits production of the vascular endothelial growth factor (VEGF) by A431 cells both in vitro and in vivo. In the latter case, h-R3 treatment (0.25-1 mg/mouse; every other day per 2 weeks) not only significantly reduced VEGF mRNA expression of A431 tumors growing subcutaneously in SCID mice but also resulted in reduction of the overall microvascular density (MVD), disappearance of dilated "mother vessels," as well as in suppression of tumor growth followed by regression of established tumors. This apparent antiangiogenic activity of h-R3 was associated with reduction in Ki67-positive tumor cell fraction and (unlike in vitro) also with an elevated apoptotic index, the latter indicative of a cytotoxic mode of action in vivo. Taken together, h-R3 is a promising new antagonist of the EGFR oncogene, the anticancer properties of which are associated with combined and potent antiproliferative, antiangiogenic and proapoptotic activity.