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Background: HER2-targeted therapies have revolutionized the treatment of HER2-positive breast cancer patients, leading to significant improvements in tumor response rates and survival. However, resistance and incomplete response remain considerable challenges. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition is a novel therapeutic strategy for the management of dyslipidemia by enhancing the clearance of low-density lipoprotein cholesterol receptors, however recent evidence also shows links between PCSK9 and cancer cells. We present an innovative immunization approach combining capsid virus-like particle (cVLP)-based vaccines against HER2 and PCSK9., Methods: The therapeutic activity of the combined vaccine was evaluated in female mice challenged with HER2-positive mammary carcinoma cells. Controls included untreated mice and mice treated with cVLP-PCSK9 and cVLP-HER2 as standalone therapies. Antibodies elicited by vaccinations were detected through ELISA immunoassay. The functional activity of the antibodies was tested in 3D-soft agar assay on human HER2 +  +  + trastuzumab sensitive and resistant cells., Results: Mice vaccinated with cVLP-HER2 + cVLP-PCSK9 displayed tumor regression from the 40th day after cell challenge in 100% of mice remaining tumor-free even 4 months later. In contrast, 83% of mice treated with cVLP-HER2 vaccine alone experienced an initial tumor regression, followed by tumor relapse in 60% of subjects. Untreated mice and mice treated with the cVLP-PCSK9 vaccine alone developed progressive tumors within 1-2 months after cell injection. The combined vaccine approach elicited strong anti-human HER2 antibody responses (reaching 1-2 mg/ml range) comprising multiple immunoglobulins isotypes. cVLP-PCSK9 vaccine elicited anti-PCSK9 antibody responses, resulting in a marked reduction in PCSK9 serum levels. Although the anti-PCSK9 response was reduced when co-administered with cVLP-HER2, it remained significant. Moreover, both cVLP-HER2 + cVLP-PCSK9 and cVLP-HER2 alone induced anti-HER2 antibodies able to inhibit the 3D growth of human HER2 +  +  + BT-474 and trastuzumab-resistant BT-474 C5 cells. Strikingly, antibodies elicited by the combined vaccination were more effective than those elicited by the cVLP-HER2 vaccine alone in the inhibition of trastuzumab-resistant C5 cells., Conclusions: The results indicate that cVLP-PCSK9 vaccination shows adjuvant activity when combined with cVLP-HER2 vaccine, enhancing its therapeutic efficacy against HER2-positive breast cancer and holding promise in overcoming the challenges posed by resistance and incomplete responses to HER2-targeted therapy., Competing Interests: Declarations. Ethics approval and consent to participate: All in vivo experiments were performed according to Italian and European laws and were authorized by the Italian Ministry of Health (letter 714–2017-PR). Consent for Publication: Not applicable. Competing interests: L.G., C.F. and A.F.S. are listed as co-inventors on a patent application covering the Delivery of a cVLP-based modular vaccine platform in a nucleic acid platform (P5856PC00). Employees of AdaptVac (L.G., C.F. and A.F.S.), a company commercializing virus-like particle display technology and vaccine, including several patents., (© 2025. The Author(s).)

Background: Non-Small Cell Lung Cancer (NSCLC) is the leading cause of cancer death worldwide. Although immune checkpoint inhibitors (ICIs) have shown remarkable clinical efficacy, they can also induce a paradoxical cancer acceleration, known as hyperprogressive disease (HPD), whose causative mechanisms are still unclear., Methods: This study investigated the mechanisms of ICI resistance in an HPD-NSCLC model. Two primary cell cultures were established from samples of a NSCLC patient, before ICI initiation ("baseline", NSCLC-B) and during HPD ("hyperprogression", NSCLC-H). The cell lines were phenotypically and molecularly characterized through immunofluorescence, Western Blotting and RNA-Seq analysis. To assess cell plasticity and aggressiveness, cellular growth patterns were evaluated both in vitro and in vivo through 2D and 3D cell growth assays and patient-derived xenografts establishment. In vitro investigations, including the evaluation of cell sensitivity to interferon-gamma (IFN-γ) and cell response to PD-L1 modulation, were conducted to explore the influence of these factors on cell plasticity regulation., Results: NSCLC-H exhibited increased expression of specific CD44 isoforms and a more aggressive phenotype, including organoid formation ability, compared to NSCLC-B. Plastic changes in NSCLC-H were well described by a deep transcriptome shift, that also affected IFN-γ-related genes, including PD-L1. IFN-γ-mediated cell growth inhibition was compromised in both 2D-cultured NSCLC-B and NSCLC-H cells. Further, the cytokine induced a partial activation of both type I and type II IFN-pathway mediators, together with a striking increase in NSCLC-B growth in 3D cell culture systems. Finally, low IFN-γ doses and PD-L1 modulation both promoted plastic changes in NSCLC-B, increasing CD44 expression and its ability to produce spheres., Conclusions: Our findings identified plasticity as a relevant hallmark of ICI-mediated HPD by demonstrating that ICIs can modulate the IFN-γ and PD-L1 pathways, driving tumor cell plasticity and fueling HPD development., Competing Interests: Declarations. Ethics approval and consent to participate: This study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). Human samples were collected after the patient gave her informed consent. The protocol was approved by the Ethics Committee Center Emilia-Romagna Region, Italy (GR-2018-12368031). Human samples and metadata including relevant clinical data were de-identified before being shared between laboratories involved in this study. All animal procedures were performed in accordance with European directive 2010/63/UE and Italian Law (No. DL26/2014). Experimental protocols were reviewed and approved by the institutional animal care and use committee of the University of Bologna and by the Italian Ministry of Health with letter 32/2020-PR. Consent for publication: Not applicable. Competing interests: Prof. Andrea Ardizzoni received research grants from Celgene, Bristol-Myers Squibb, Ipsen, and Roche; and honoraria for advisory roles from Bristol-Myers Squibb, Merck Sharp & Dohme, ROCHE, AstraZeneca, and Eli Lilly outside of the submitted work. Dr. Francesco Gelsomino received honoraria or personal fees for the advisory role or consulting from Eli Lilly, Novartis, AstraZeneca, Pfizer, Regeneron and Bristol-Myers Squibb outside the submitted work., (© 2025. The Author(s).)

Lipid rafts are dynamic microdomains enriched with cholesterol and sphingolipids that play critical roles in cellular processes by organizing and concentrating specific proteins involved in signal transduction. The interplay between lipid rafts, raft-associated caveolae and the human epidermal growth factor receptors has significant implications in cancer biology, particularly in breast and gastric cancer therapy resistance. This review examines the structural and functional characteristics of lipid rafts, their involvement in EGFR and HER2 signaling, and the impact of lipid rafts/CXCL12/CXCR4/HER2 axis on bone metastasis. We also discuss the potential of targeting lipid rafts and caveolin-1 to enhance therapeutic strategies against HER2-positive cancers and the impact of co-localization of trastuzumab or antibody drug conjugates with caveolin-1 on therapy response. Emerging evidence suggests that disrupting lipid raft integrity or silencing caveolin-1, through several strategies including cholesterol-lowering molecules, can influence HER2 availability and internalization, enhancing anti-HER2 targeted therapy and offering a novel approach to counteract drug resistance and improve treatment efficacy., (© 2024. The Author(s).)

Antibodies directed against surface antigens of tumor cells are commonly found in sera of cancer patients and of oncological animal models. Polyclonal antibodies directed against various epitopes of the same antigen may be spontaneously elicited by tumor antigens or may result from the administration of specific vaccines and other immunostimulating treatments. Furthermore, after therapeutic administration of monoclonal antibodies, the antibody will be detectable in the bloodstream for several weeks. Circulating antibodies are easily detected with enzyme-linked immunosorbent assays (ELISA) and other immunometric tests which, however, cannot tell whether the antibodies are functional, i.e. whether they can significantly inhibit (or enhance) tumor growth. One possibility would be to treat conventional (i.e. bi-dimensional, 2D) tumor cell cultures with antibody-containing sera. However, in several instances, it was found that 2D cultures were poorly sensitive, even to powerful monoclonal antibodies like trastuzumab, whereas three-dimensional (3D) cultures may better reveal the tumor-inhibitory activity of circulating antibodies. We describe here a breast cancer 3D soft agar colony growth inhibition assay that was developed to quantify the tumor cell inhibitory activity of antibodies against human HER-2 elicited in mice by specific vaccines. The assay might be readily modified to analyze antibodies against different surface antigens expressed by other tumor types and also for testing of new monoclonal antibodies and nanobodies., (Copyright © 2024 Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.)

Cancer vaccines are increasingly being studied as a possible strategy to prevent and treat cancers. While several prophylactic vaccines for virus-caused cancers are approved and efficiently used worldwide, the development of therapeutic cancer vaccines needs to be further implemented. Virus-like particles (VLPs) are self-assembled protein structures that mimic native viruses or bacteriophages but lack the replicative material. VLP platforms are designed to display single or multiple antigens with a high-density pattern, which can trigger both cellular and humoral responses. The aim of this review is to provide a comprehensive overview of preventive VLP-based vaccines currently approved worldwide against HBV and HPV infections or under evaluation to prevent virus-caused cancers. Furthermore, preclinical and early clinical data on prophylactic and therapeutic VLP-based cancer vaccines were summarized with a focus on HER-2-positive breast cancer.