Epidermal growth factor receptor (EGFR) is a central transmitter of mitogenic signals in epithelial cells; enhanced EGFR activity is observed in many tumors of epithelial origin. S100A6 is a small ...calcium‐binding protein, characteristic mainly of epithelial cells and fibroblasts, strongly implicated in cell proliferation and upregulated in tumors. In this study, using biochemical assays along with immunohistochemical and immunocytochemical analysis of organotypic and standard cultures of HaCaT keratinocytes with S100A6 overexpression or knock‐down, we have examined the effect of S100A6 on EGFR activity and downstream signaling. We found that HaCaT cells overexpressing S100A6 had enhanced EGFR, phospho EGFR, and phospho extracellular signal‐regulated kinase 1/2 (pERK1/2) staining intensity and level coupled to higher signal transducer and activator of transcription 3 (STAT3) activity. Conversely, S100A6 knockdown cells had impaired EGFR signaling that could be enhanced by addition of recombinant S100A6 to the culture media. Altogether the results show that S100A6 may exert its proproliferative effects through activating EGFR.
We found that HaCaT cells overexpressing S100A6 had enhanced epidermal growth factor receptor (EGFR), phospho EGFR, and phospho extracellular signal‐regulated kinase 1/2 (pERK1/2) staining intensity and level coupled to higher signal transducer and activator of transcription 3 activity. Conversely, S100A6 knock‐down cells had impaired EGFR signaling that could be enhanced by addition of recombinant S100A6 to the culture media. Altogether the results show that S100A6 may exert its pro‐proliferative effects through activating EGFR.
The immune checkpoints are regulatory molecules that maintain immune homeostasis in physiological conditions. By sending T cells a series of co-stimulatory or co-inhibitory signals via receptors, ...immune checkpoints can both protect healthy tissues from adaptive immune response and activate lymphocytes to remove pathogens effectively. However, due to their mode of action, suppressive immune checkpoints may serve as unwanted protection for cancer cells. To restore the functioning of the immune system and make the patient's immune cells able to recognize and destroy tumors, monoclonal antibodies are broadly used in cancer immunotherapy to block the suppressive or to stimulate the positive immune checkpoints. In this review, we aim to present the current state of application of monoclonal antibodies in clinics, used either as single agents or in a combined treatment. We discuss the limitations of these therapies and possible problem-solving with combined treatment approaches involving both non-biological and biological agents. We also highlight the most promising strategies based on the use of monoclonal or bispecific antibodies targeted on immune checkpoints other than currently implemented in clinics.
Tumor-driven immune suppression is a major barrier to successful immunotherapy in ovarian carcinomas (OvCa). Among various mechanisms responsible for immune suppression, arginase-1 (ARG1)-carrying ...small extracellular vesicles (EVs) emerge as important contributors to tumor growth and tumor escape from the host immune system. Here, we report that small EVs found in the ascites and plasma of OvCa patients contain ARG1. EVs suppress proliferation of CD4
and CD8
T-cells in vitro and in vivo in OvCa mouse models. In mice, ARG1-containing EVs are transported to draining lymph nodes, taken up by dendritic cells and inhibit antigen-specific T-cell proliferation. Increased expression of ARG1 in mouse OvCa cells is associated with accelerated tumor progression that can be blocked by an arginase inhibitor. Altogether, our studies show that tumor cells use EVs as vehicles to carry over long distances and deliver to immune cells a metabolic checkpoint molecule - ARG1, mitigating anti-tumor immune responses.
The prognosis for B-cell precursor acute lymphoblastic leukemia patients with Mixed-Lineage Leukemia (MLL) gene rearrangements (MLLr BCP-ALL) is still extremely poor. Inhibition of anti-apoptotic ...protein BCL-2 with venetoclax emerged as a promising strategy for this subtype of BCP-ALL, however, lack of sufficient responses in preclinical models and the possibility of developing resistance exclude using venetoclax as monotherapy. Herein, we aimed to uncover potential mechanisms responsible for limited venetoclax activity in MLLr BCP-ALL and to identify drugs that could be used in combination therapy. Using RNA-seq, we observed that long-term exposure to venetoclax in vivo in a patient-derived xenograft model leads to downregulation of several tumor protein 53 (TP53)-related genes. Interestingly, auranofin, a thioredoxin reductase inhibitor, sensitized MLLr BCP-ALL to venetoclax in various in vitro and in vivo models, independently of the p53 pathway functionality. Synergistic activity of these drugs resulted from auranofin-mediated upregulation of NOXA pro-apoptotic protein and potent induction of apoptotic cell death. More specifically, we observed that auranofin orchestrates upregulation of the NOXA-encoding gene Phorbol-12-Myristate-13-Acetate-Induced Protein 1 (PMAIP1) associated with chromatin remodeling and increased transcriptional accessibility. Altogether, these results present an efficacious drug combination that could be considered for the treatment of MLLr BCP-ALL patients, including those with TP53 mutations.
B‐cell precursor acute lymphoblastic leukemia (BCP‐ALL) is a genetically heterogeneous blood cancer characterized by abnormal expansion of immature B cells. Although intensive chemotherapy provides ...high cure rates in a majority of patients, subtypes harboring certain genetic lesions, such as MLL rearrangements or BCR‐ABL1 fusion, remain clinically challenging, necessitating a search for other therapeutic approaches. Herein, we aimed to validate antioxidant enzymes of the thioredoxin system as potential therapeutic targets in BCP‐ALL. We observed oxidative stress along with aberrant expression of the enzymes associated with the activity of thioredoxin antioxidant system in BCP‐ALL cells. Moreover, we found that auranofin and adenanthin, inhibitors of the thioredoxin system antioxidant enzymes, effectively kill BCP‐ALL cell lines and pediatric and adult BCP‐ALL primary cells, including primary cells cocultured with bone marrow‐derived stem cells. Furthermore, auranofin delayed the progression of leukemia in MLL‐rearranged patient‐derived xenograft model and prolonged the survival of leukemic NSG mice. Our results unveil the thioredoxin system as a novel target for BCP‐ALL therapy, and indicate that further studies assessing the anticancer efficacy of combinations of thioredoxin system inhibitors with conventional anti‐BCP‐ALL drugs should be continued.
In B‐cell precursor acute lymphoblastic leukemia (BCP‐ALL), we observed oxidative stress along with increased expression of the enzymes of the thioredoxin antioxidant system. Inhibition of these enzymes with auranofin and adenanthin triggered oxidative and endoplasmic reticulum stress and effectively killed BCP‐ALL cells in vitro and in vivo. Our results unveil thioredoxin system as a novel target for BCP‐ALL therapy.
Breast cancer (BC) has traditionally been considered to be not inherently immunogenic and insufficiently represented by immune cell infiltrates. Therefore, for a long time, it was thought that the ...immunotherapies targeting this type of cancer and its microenvironment were not justified and would not bring benefits for breast cancer patients. Nevertheless, to date, a considerable number of reports have indicated tumor-infiltrating lymphocytes (TILs) as a prognostic and clinically relevant biomarker in breast cancer. A high TILs expression has been demonstrated in primary tumors, of both, HER2-positive BC and triple-negative (TNBC), of patients before treatment, as well as after treatment with adjuvant and neoadjuvant chemotherapy. Another milestone was reached in advanced TNBC immunotherapy with the help of the immune checkpoint inhibitors directed against the PD-L1 molecule. Although those findings, together with the recent developments in chimeric antigen receptor T cell therapies, show immense promise for significant advancements in breast cancer treatments, there are still various obstacles to the optimal activity of immunotherapeutics in BC treatment. Of these, the immunosuppressive tumor microenvironment constitutes a key barrier that greatly hinders the success of immunotherapies in the most aggressive types of breast cancer, HER2-positive and TNBC. Therefore, the improvement of the current and the demand for the development of new immunotherapeutic strategies is strongly warranted.
Immunotherapy of cancer had its early beginnings in the times when the elements of the immune system were still poorly characterized. However, with the progress in molecular biology, it has become ...feasible to re-engineer T cells in order to eradicate tumour cells. The use of synthetic chimeric antigen receptors (CARs) helped to re-target and simultaneously unleash the cytotoxic potential of T cells. CAR-T therapy proved to be remarkably effective in cases of haematological malignancies, often refractory and relapsed. The success of this approach yielded two Food and Drug Administration (FDA) approvals for the first "living drug" modalities. However, CAR-T therapy is not without flaws. Apart from the side effects associated with the treatment, it became apparent that CAR introduction alters T cell biology and the possible therapeutic outcomes. Additionally, it was shown that CAR-T approaches in solid tumours do not recapitulate the success in the haemato-oncology. Therefore, in this review, we aim to discuss the recent concerns of CAR-T therapy for both haematological and solid tumours. We also summarise the general strategies that are implemented to enhance the efficacy and safety of the CAR-T regimens in blood and solid malignancies.
Aims
The efficacy of cell therapy in patients with stress urinary incontinence (SUI) is lower than expected. The aim of this study was to determine the injection accuracy rate both with transurethral ...and periurethral route.
Methods
Autologous intraurethral cell transplantation was performed in female goats. The cells were injected either periurethrally (PERI group, two depots/animal, n = 8) or transurethrally (TRANS group, eight depots/animal, n = 11). Transurethral injections were performed under endoscopic guidance. The number and distribution of cell depots in urethras were analyzed in the three‐step protocol: 1) screening of whole explants by in vivo imaging system; 2) systematic microscopic analysis of raw 10 μm cross‐sections; 3) immunohistochemistry. As control, four urethras collected 1 day after transurethral transplantation were used. Episodes of cell suspension leakages after needle withdrawal were noted.
Results
In all experimental animals depots were identified in the urethral wall 28 days after transplantation. The mean percentage of depots located in the urethral wall in relation to all performed injections amounted to 68.7% and 67.0% for PERI and TRANS groups, respectively. The mean proportions of depots which were identified in external urethral sphincter (EUS) amounted 18.8% and 17.1%, respectively. Suspension leakage was observed in 19% of transurethral injections.
Conclusions
Although majority of cell depots were administrated accurately into the urethral wall, the precise delivery of cells into EUS is limited regardless of injection method. The insufficient accuracy of cell delivery into EUS and cell suspension leakage can contribute to the low efficacy of cell therapy in human patients with SUI.
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