Polyclonal antibody-induced downregulation of HER1/EGFR and HER2 surpasses the effect of combinations of specific registered antibodies.

Background: Antitumor therapies targeting HER1/EGFR and HER2, such as monoclonal antibodies (MAbs) and tyrosine-kinase inhibitors (TKIs), have demonstrated a significant clinical benefit, but the emergence of resistance limits long-term efficacy. While secondary HER1 mutations confer tolerance to TKI, compensatory upregulation of HER2 drives resistance to anti-HER1 MAbs, which identifies MAb combinations targeting both receptors as an attractive therapeutic strategy. Nevertheless, toxicity hampers the clinical validation of this approach. Alternatively, cancer vaccines may induce antibodies directed against several antigens with less concern about induced toxicity. Methods: Polyclonal antibodies (PAbs) targeting HER1 and HER2 were induced in mice or rabbits through immunization. Recognition of different epitopes on targets by PAbs was validated by phage-display technology. Receptor downregulation was evaluated by flow cytometry, immunofluorescence, and Western blot. MTT assays assessed cytotoxicity, while the antitumor effect of PAbs was assayed in nude mice. Results: PAbs promoted degradation of HER1 and HER2 regarding clinical MAbs or their combinations. As a result, inhibition of cytotoxicity on tumor cell lines was improved, even in the presence of oncogenic mutations in HER1, as well as in cetuximab-insensitive cells. Accordingly, the antitumor effect of vaccination-induced PAbs was observed in lung tumor lines representative of sensitivity or resistance to HER1 targeting therapies. Conclusions: Immunization against HER1 and HER2 receptors offers an alternative to passive administration of combinations of MAbs, since vaccination-induced PAbs promote the downregulation of both receptors and they have a higher impact on the survival of tumor cells.

Immuno-toxicological evaluation of her1 cancer vaccine in non-human primates: a 6-month subcutaneous study.

Purpose: A vaccine composition based on the extracellular domain of the human epidermal growth factor receptor 1 (HER1-ECD) and the combination of VSSP (very small size proteoliposomes) and Montanide ISA 51 adjuvants when used by intramuscular route, demonstrated promising results in preclinical studies. However, in order to avoid potential adverse events due to the use of Montanide, it is proposed to modify the vaccine formulation by using VSSP (very small size proteoliposomes) adjuvant alone, and to evaluate the quality of subcutaneously induced immune response. This study aimed to assess the immunotoxicological effects of HER1 vaccine in Cercopithecus aethiops.Materials and methods: Fifteen monkeys were randomized into four groups: Negative Control (Tris/NaCl, s.c.), Positive Control (200 µg HER1-ECD/VSSP/Montanide ISA-51 VG, i.m), Low Dose (200 µg HER1-ECD/VSSP/Tris NaCl, s.c.) and High Dose (800 µg HER1-ECD/VSSP/Tris NaCl, s.c). All monkeys received 7 doses and were daily inspected for clinical signs. Body weight, rectal temperature, cardiac and respiratory rates were measured during the study, and electrocardiographical and ophthalmological studies were performed. Humoral and cellular immune response and clinical pathology parameters were analyzed.Results: Animal's survival in the study was 100% (n = 15). Administration site reactions were observed in the Positive Control animals (n = 4). HER1 vaccine administered subcutaneously (High Dose Group) achieved good IgG antibody titers although lower than the Positive Control group, but with higher ability to inhibit HER1 phosphorylation. Conclusions: This suggests that the alternative of eliminating the use of Montanide in the HER1 vaccine preparation and the using subcutaneous route is feasible.

Targeting HER3, a Catalytically Defective Receptor Tyrosine Kinase, Prevents Resistance of Lung Cancer to a Third-Generation EGFR Kinase Inhibitor.

Although two growth factor receptors, EGFR and HER2, are amongst the best targets for cancer treatment, no agents targeting HER3, their kinase-defective family member, have so far been approved. Because emergence of resistance of lung tumors to EGFR kinase inhibitors (EGFRi) associates with compensatory up-regulation of HER3 and several secreted forms, we anticipated that blocking HER3 would prevent resistance. As demonstrated herein, a neutralizing anti-HER3 antibody we generated can clear HER3 from the cell surface, as well as reduce HER3 cleavage by ADAM10, a surface metalloproteinase. When combined with a kinase inhibitor and an anti-EGFR antibody, the antibody completely blocked patient-derived xenograft models that acquired resistance to EGFRi. We found that the underlying mechanism involves posttranslational downregulation of HER3, suppression of MET and AXL upregulation, as well as concomitant inhibition of AKT signaling and upregulation of BIM, which mediates apoptosis. Thus, although HER3 is nearly devoid of kinase activity, it can still serve as an effective drug target in the context of acquired resistance. Because this study simulated in animals the situation of patients who develop resistance to EGFRi and remain with no obvious treatment options, the observations presented herein may warrant clinical testing.

HER1-based vaccine: Simultaneous activation of humoral and cellular immune response.

The human epidermal growth factor receptor 1 (HER1) is a tumor-associated antigen that has been validated as a clinical target for several passive, non-immune therapies currently approved for the treatment of epithelial tumors. HER1 is an oncogene that not only promotes tumor progression and survival, but also immune escape. Its overexpression in some epithelial malignancies has been correlated with a poor prognosis. We developed an approach to target HER1 by specific active immunotherapy, recognizing the extracellular domain of the receptor, using a combination of VSSP and Montanide ISA 51 as adjuvants. We summarize the results obtained with this vaccine in both the preclinical and clinical settings, emphasizing the importance of the induction of both humoral and cellular responses for the success of cancer vaccines as safe therapeutic alternatives for the treatment of cancer.

Ausencia de efectos de la terapia floral aplicada a adultos jóvenes con el fin de mejorar su memoria / Lack of effects of flower therapy applied to young adults to improve their memory function

Se realizó un estudio experimental controlado a doble ciegas para comprobar la efectividad atribuida a las llamadas esencias florales de Bach para mejorar las funciones de memoria. Para ello se administró una mezcla de 5 flores (Chestnut Bud, Red Chestnut, Wild Oat, Honey Suckle y Clematis) obtenidas de la Farmacia Homeopática (23 esq. a M, Vedado La Habana) a estudiantes de 1er año de la Universidad de La Habana. Se constituyeron 3 grupos, uno sin tratamiento y los otros dos que recibieron 4 aplicaciones diarias durante 10 días de 4 gotas sublinguales de la mezcla floral o un placebo que fue el vehículo en que se preparan y conservan las flores. Para evaluar el efecto aludido se aplicó a todos los participantes un test de memoria (test de Rey) en días sucesivos. En el primer día les fue presentada una lista de 15 palabras y se recogió por escrito la cantidad de palabras correctas que fueron capaces de evocar de forma inmediata. Este procedimiento se repitió 5 veces y se notó un incremento progresivo en el número de aciertos. Al día siguiente se les entregó una historieta escrita que contenía, dispersas entre otras, las 15 palabras de la lista y se le pidió subrayar las que pudieran identificar como pertenecientes a esa lista. El análisis estadístico de los resultados (ANOVA) no permitió identificar diferencias significativas entre los grupos en ninguna de las pruebas. Estos resultados no apoyan la hipótesis de que tales preparados ejerzan un efecto real y sugieren que su posible éxito en algunos casos es de tipo placebo.

An experimental double blind controlled study was carried out to confirm the effectiveness of the so-called Bach flower essences in the improvement of memory functions. To this end, a five flower mixture (Chesnut, Bud, Red Chesnut, Wild Oat, Honey Suckle and Clematis) obtained from homeopathic drugstore located in Havana was administered to first-year university students at the University of Havana. Three groups were created, one without treatment and the two other groups received 4 daily doses for 10 days at a rate of 4 drops sublingually of the flower mixture or the placebo in which flower are prepared and preserved. To assess the effect, a memory test (Rey´s test) was applied to the participants in the subsequent days. The first day, they were given a list of 15 words and the number of correct words that they were able to remember immediately was recorded in writing. This method was repeated 5 times; there was a progressive increase in the number of correct words remembered. On the following day, they were given some cartoon story containing among other the 15 words from the list and the participants were asked to identify them. The Statistical analysis (ANOVA) of the results did not show significant differences among the groups in none of the tests. These results did not support the hypothesis that these flower mixtures have a real impact and suggested that their possible success in some cases be of placebo-type.