Toll-like receptors: New targets for multiple myeloma treatment?

Despite recent biomedical improvements in treating multiple myeloma, this disease still remains incurable. Toll-like receptors (TLRs) are key immune receptors that recognize conserved molecular patterns expressed by pathogens and damaged cells. Activation of TLRs can induce several effects including inflammatory responses, modulation of cell cycle, apoptosis, or regulation of cell metabolism. In multiple myeloma there is a dysregulated signalling of TLRs due to an abnormal presence of certain pathogens and release of molecules from damaged cells. Thus, TLRs could be critical players for tumour microenvironment and multiple myeloma progression. This haematological malignancy is characterized by a high percentage of recurrences, where many patients can develop residual drug-resistant malignant cells. Strategic targeting of TLRs might result in novel therapeutic combinations that improve the response to current treatments, reducing relapses. This review examines the potential of TLRs as targets for the treatment of multiple myeloma, making a particular emphasis on their therapeutic applications

Efecto de Selinexor y Panobinostat sobre los niveles de PD‐L1 en células de mieloma múltiple

El mieloma múltiple (MM) es una neoplasia hematológica maligna caracterizada por la presencia de células plasmáticas (PCs) clonales anormales en la médula ósea, con potencial de crecimiento incontrolado y, que además secretan una inmunoglobulina monoclonal cuya acumulación provoca una disfunción orgánica, causando lesiones óseas, lesión renal, anemia e hipercalcemia. A pesar de las numerosas investigaciones y los avances realizados en la terapia frente a la patología, sigue siendo una enfermedad incurable. Como posible terapia frente a esta enfermedad, se ha propuesto el bloqueo del eje PD-1/PD-L1; sin embargo, los datos discordantes de la literatura sobre la expresión del mismo y las toxicidades relacionadas hacen que se necesiten investigaciones adicionales para optimizar el potencial terapéutico de esta clase de inmunoterapia.En el presente Trabajo Fin de Grado, se aborda el análisis de la expresión de PD-L1 en cuatro líneas de MM tras la administración de diferentes concentraciones de los fármacos Selinexor y Panobinostat; con el objetivo de, en un futuro, emplearlos como estrategia terapéutica de combinación frente al MM. Para ello, se ha comprobado la capacidad de Selinexor y Panobinostat de inducir muerte celular de manera dosis-dependiente en cuatro líneas de MM y posterior análisis de la expresión superficial de PD-L1 en la membrana plasmática de dichas células.En los resultados, se pudo comprobar que las dosis de los fármacos provocaron un aumento de la muerte celular en todas las líneas. También se observó que los patrones de expresión de la proteína PD-L1 no seguían una tendencia uniforme en las cuatro líneas celulares; sin embargo, las dosis de Selinexor y Panobinostat empleadas, todas ellas indujeron un aumento de la expresión; lo que podría conllevar la evasión de la vigilancia inmune sobre las células cancerosas en presencia de dichos fármacos.<br /

Apoptosis inducida por el inhibidor del proteasoma Ixazomib en células de mieloma humano

El mieloma múltiple humano es una neoplasia hematológica caracterizada por una proliferación maligna de células B plasmáticas productoras de ingentes cantidades de anticuerpos, procedentes de un solo clon y cuya expansión tiene lugar en la médula ósea. A pesar de los avances realizados en la terapia frente a esta patología, continúa siendo una enfermedad incurable. El estudio del mecanismo de acción de nuevos fármacos introducidos para el tratamiento del mieloma múltiple podría aportar información útil en la búsqueda de nuevas estrategias terapéuticas. El presente trabajo aborda el análisis de las vías de muerte celular implicadas en la acción del inhibidor del proteasoma Ixazomib, recientemente aprobado por la FDA y la EMA. En concreto, se ha comprobado la capacidad de Ixazomib de inducir muerte celular de manera dosis-dependiente en diversas líneas de mieloma múltiple, así como su efecto sobre el ciclo celular provocando, en la mayoría de las líneas celulares estudiadas, una parada en las fases G2/M. Además, ha quedado demostrada la activación de caspasa 3, principal caspasa ejecutora, en células tratadas con Ixazomib y la variación en los niveles de expresión de proteínas pertenecientes a la familia Bcl-2, lo cual podría indicar su directa implicación en el mecanismo de muerte celular desarrollado por éste. En paralelo, se ha descartado la posible sinergia entre Ixazomib e inhibidores de VCP/p97 (DBeQ y CB-5083) pero ha quedado constatada una clara sinergia entre Ixazomib y cloroquina que, en un futuro, podría constituir una nueva estrategia terapéutica de combinación frente al mieloma múltiple

Silver-based terpyridine complexes as antitumor agents

Silver complexes bearing substituted terpyridine or tetra-2-pyridinylpyrazine ligands have been prepared and structurally characterised. The study of the anticancer properties of silver complexes with this type of ligands is scarce, despite the possibilities of combining the properties of the metal and the ability of the ligands for DNA binding. Here, the antiproliferative activity, stability, CT-DNA binding and mechanism of cell death of these types of derivatives are studied. High cytotoxicity against different tumour cells was observed, and, more important, a great selectivity index has been detected between tumour cells and healthy Lymphocytes T for some of these compounds. The CT-DNA interaction study has shown that these derivatives are be able to interact with CT-DNA via moderate intercalation. Furthermore, cell death studies indicate that these derivatives promote the apoptosis via mitochondrial pathway

Efficient encapsulation of theranostic nanoparticles in cell-derived exosomes: leveraging the exosomal biogenesis pathway to obtain hollow gold nanoparticle-hybrids

Exosomes can be considered natural targeted delivery systems able to carry exogenous payloads, drugs or theranostic nanoparticles (NPs). This work aims to combine the therapeutic capabilities of hollow gold nanoparticles (HGNs) with the unique tumor targeting properties provided by exosomes. Here, we tested different methods to encapsulate HGNs (capable of absorbing light in the NIR region for selective thermal ablation) into murine melanoma cells derived exosomes (B16-F10-exos), including electroporation, passive loading by diffusion, thermal shock, sonication and saponin-assisted loading. These methods gave less than satisfactory results: although internalization of relatively large NPs into B16-F10-exos was achieved by almost all the physicochemical methods tested, only about 15% of the exosomes were loaded with NPs and several of those processes had a negative effect regarding the morphology and integrity of the loaded exosomes. In a different approach, B16-F10 cells were pre-incubated with PEGylated HGNs (PEG-HGNs) in an attempt to incorporate the NPs into the exosomal biogenesis pathway. The results were highly successful: exosomes recovered from the supernatant of the cell culture showed up to 50% of HGNs internalization. The obtained hybrid HGN-exosome vectors were characterized with a battery of techniques to make sure that internalization of HGNs did not affect exosome characteristics compared with other strategies. PEG-HGNs were released through the endosomal-exosome biogenesis pathway confirming that the isolated vesicles were exosomes

Ecto-calreticulin expression in multiple myeloma correlates with a failed anti-tumoral immune response and bad prognosis

Immunogenic cell death (ICD) has been proposed to be a crucial process for antitumor immunosurveillance. ICD is characterized by the exposure and emission of Damage Associated Molecular Patterns (DAMP), including calreticulin (CRT). A positive correlation between CRT exposure or total expression and improved anticancer immunosurveillance has been found in certain cancers, usually accompanied by favorable patient prognosis. In the present study, we sought to evaluate CRT levels in the plasma membrane of CD38+ bone marrow mononuclear cells (BMMCs) isolated from 71 patients with varying degrees of multiple myeloma (MM) disease and examine the possible relationship between basal CRT exposure and the bone marrow immune microenvironment, as well as its connection with different clinical markers. Data show that increased levels of cell surface-CRT were associated with more aggressive clinical features and with worse clinical prognosis in MM. High CRT expression in MM cells was associated with increased infiltration of NK cells, CD8+ T lymphocytes and dendritic cells (DC), indicative of an active anti-tumoral immune response, but also with a significantly higher presence of immunosuppressive Treg cells and increased expression of PD-L1 in myeloma cells