Browsing by study line "Cancer"

Immunotherapies have exponentially gained interest recently as they are less invasive than traditional cancer treatment. Chimeric Antigen Receptor T cell (CAR T) treatment is among the latest breakthroughs and there are currently five FDA and EMA approved CAR T treatments on the market. Despite their potential, CAR T treatment may have serious adverse effects, they are costly, and the suitable patient population is small. In addition, CAR T treatment works best on haematological cancers, with further challenges in treating solid tumours. Treatment safety is a main concern because CAR Ts may start damaging healthy tissue expressing a target antigen, which can be fatal for some patients. The ongoing research on CAR T treatment for solid tumours is prevalent, but none have been approved by FDA or EMA. This study investigated organs from anti-SSEA-4 CAR T treated mice post an in vivo dose-escalating experiment on immunocompromised mice with human ovarian adenocarcinoma (OVCAR4) xenografts. The study included nine treatment groups in total, four dose-escalating treatment groups, three correlating non-tumour treatment groups and both a tumour control and a no-treatment, no-tumour control group. Differences in the tissues regarding the target antigen SSEA-4, non-transduced T cells and SSEA-4 targeted CAR Ts were analysed with H&E and immunostainings. SSEA-4 expression was found in the kidneys, ovarian follicles and in the gastrointestinal muscular layer. In spite of the SSEA-4 expression on healthy tissues, signs of on-target, off-tumour effects were limited in these organs. T cell infiltrates were found mostly in the intestine, stomach, fallopian tubes, and lungs, of which CAR Ts infiltrated specifically the intestine, stomach, and fallopian tubes. Nonetheless, no clear correlation between endemic SSEA-4 expression and CAR T infiltrates was found. Anti-SSEA-4 CAR Ts had an anti-tumour effect on all studied doses. However, some of the high dose mice showed signs of health deterioration. Despite the weak antigen expression on tumours, many immunologically ‘hot’ tumours with lymphocytes were found which proves a successful tumour infiltration. CAR T dose-limiting, and combinatorial target antigens need to be further investigated to improve treatment safety and before advancing into clinical trials.  

New treatment methods are urgently needed for glioblastoma (GBM), the most common malignant primary brain tumor in adults, that currently lacks any curative treatment. Targeted therapeutic approaches have shown promising results already, but common drug delivery vehicles come with efficacy issues and are restricted by their safety and toxicity profiles. Exosomes, cell-produced nanosized vesicles, have emerged as a new potential carrier for gene therapies in cancer treatment due to their natural material transport properties, biocompatibility, and specificity in transporting cargo to the target cells. These extracellular vesicles have the additional advantage of being able to cross the blood-brain-barrier (BBB), which makes them especially valuable for brain malignancies, such as glioblastomas. So far, gene therapy approaches in exosomes have focused on RNA in cancer treatment, but research findings are limited with plasmid-based gene therapies using exosomes. The main concern has been whether the increased plasmid size would decrease the transfection efficiency of the plasmid into the exosomes. This study aimed at setting-up exosomes as plasmid-based gene therapy nanocarriers. To achieve this, different plasmid-based gene therapies were tested, including the targeting of common aberrations of GBM cells to impair proliferation and the use of cytotoxins to induce apoptosis in the target cells. The plasmids were transfected into exosomes and subsequently inoculated into patient-derived glioblastoma cells with the aim of decreasing the number of glioblastoma cells. The findings of this study demonstrate a successful set-up of an exosome-based gene therapy in patient-derived glioblastoma cells by using engineered HEK293FT cell derived exosomes consisting of a plasmid-based combination gene therapy encoding the cytotoxins Granzyme B and Diphtheria toxin fragment A.

The gastrointestinal (GI) epithelium is composed of a single layer of cells with a turnover time of only a few days. Due to its location at the barrier between GI tract contents and the underlaying mucosa, the epithelium is constantly exposed to stress such as toxic agents and a variety of pathogens and susceptible to injury. Accordingly, the homeostatic growth as well as repair of injury in epithelium must be efficient and strictly regulated. Misregulated repair of the injured epithelium can lead to pathologies such as chronic inflammation or cancer. Underlying stromal cells such as fibroblasts provide growth factors and other signaling molecules regulating the epithelial cell stemness, differentiation and repair, but the stromal regulatory pathways during regeneration are poorly understood. The aim of this study was to establish a consensus view on the heterogeneity of GI fibroblasts, as well as to map potential epithelium derived signals affecting fibroblast function in homeostatic and injury situations using literature review, in silico approaches, and murine primary intestinal fibroblast culture. Seurat and CellChat R packages were used to perform integration and interaction analyses of six previously published mouse and three human single- cell RNA-sequencing datasets of colonic epithelial and mesenchymal cells isolated in homeostatic and/or inflammatory conditions. Murine primary intestinal fibroblasts were treated with identified potential signaling factors ex vivo and 3’RNAseq was performed to identify transcriptional responses. Both mesenchymal and epithelial cell clusters were identified in the scRNAseq data. Interestingly, similar fibroblast populations could be found in the murine and human data. I identified several epithelium-derived signaling molecules potentially targeting GI fibroblasts and focused on Gas6-Axl pathway and lactate. I confirmed high and specific expression of the Gas6 receptor Axl in intestinal fibroblasts, but recombinant Gas6 failed to induce significant changes in cultured primary fibroblasts. Lactate-treated primary intestinal fibroblasts reprogrammed their transcriptome with main alterations in metabolic pathways and induction of neutrophil-attracting chemokines. In this work I suggest a consensus model for GI fibroblast subpopulations and suggest epithelium derived lactate as a powerful means to reprogram fibroblasts.