BET-directed PROTACs in triple negative breast cancer cell lines MDA-MB-231 and MDA-MB-436.

PURPOSE: This study aims to find whether the proliferation and migration of triple negative breast cancer (TNBC) cell lines can be reduced by treatment with bromodomain and extra-terminal domain (BET) inhibitor JQ1 and BET protein targeting chimeras (PROTACs) ARV-771 and MZ1. METHODS: Cytotoxicity tests, scratch migration assays and western blot proteome profiler arrays for protein expression of cancer-related proteins were used to evaluate the impact of a BET-inhibitor and two BET-directed PROTACs on cell viability, migration and on protein expression. RESULTS: JQ1 and the PROTACs MZ1 and ARV-771 significantly inhibited the growth and migration of the KRAS G13D-mutated MDA-MB-231 cells. In this cell line, the PROTACs suppressed the residual expression of ERBB2/HER2, 3 and 4 that are essential for the proliferation of breast cancer cells and this cell line proved sensitive to HER2 inhibitors. In contrast, the effects of the PROTACs on the protein expression of MDA-MB-436 cells mostly affected cytokines and their cognate receptors. CONCLUSION: The degradation of BET-protein by PROTACs demonstrated significant anti-proliferative effects. The KRAS-mutated MDA-MB-231 cells belong to the low-HER2 expressing tumors that have a poorer prognosis compared to HER2-null patients. Since first oral PROTACs against tumor hormone receptors are in clinical trials, this mode of tumor therapy is expected to become an important therapeutic strategy in the future treatment of TNBC.

BRD4-targeting PROTACs Synergize With Chemotherapeutics Against Osteosarcoma Cell Lines.

BACKGROUND/AIM: Osteosarcoma at an advanced stage has a poor outcome, and novel targeted therapies are needed, especially for metastatic disease. Bromodomain inhibitors (BETi) are epigenetic modulators that broadly impair the expression of oncogenic proteins and exert antitumor effects. BETi can be combined with chemotherapeutics to increase therapeutic responses with superior effects in the form of proteolysis targeting chimeras (PROTACs) that degrade proteins of interest (POI) in multiple cycles. This work aimed to investigate the efficacy of BETi, such as JQ1, dBET57, and MZ1 PROTACs in combination with cytotoxic drugs against osteosarcoma cell lines. MATERIALS AND METHODS: Chemosensitivity of the osteosarcoma cell lines HOS, Saos-2, MG-63, and G292 were tested with BET-directed agents alone or in combination with cytotoxic drugs comprising cisplatin, doxorubicin, topotecan, and gemcitabine using cell viability assays. RESULTS: The BET degraders exhibited highest toxicity to HOS cells and showed synergistic activity in combination with the chemotherapeutics, except for the degrader - topotecan/gemcitabine combinations. Highest synergy between BET agents and chemotherapeutics were found for the more chemoresistant Saos-2 cells and potentiation of toxicity in MG-63 cells for the BET agents - doxorubicin combinations and the MZ1-topotecan pair. HOS and Saos-2 cell lines had reduced protein expression of AXL, BCL-X, e-cadherin, CAIX, EpCAM, ErbB2, and vimentin in response to JQ1, MZ1, and BET57. CONCLUSION: The study suggests that the application of novel BET PROTACs in combination with chemotherapeutics could represent a new therapeutic option to improve the therapy of osteosarcomas. First orally available PROTACs have reached clinical trials.

[Update and Trends in Breast Reconstruction After Mastectomy]. / Update und Trends bei der plastisch-chirurgischen Brustrekonstruktion nach Mastektomie.

Due to refinements in operating techniques, autologous breast reconstruction has become part of standard care. It has become more difficult to advise patients due to the expansion of oncologic options for mastectomy, radiation therapy and the variety of reconstructive techniques. The goal of reconstruction is to achieve oncologically clear margins and a long-term aesthetically satisfactory result with a high quality of life. Immediate reconstruction preserves the skin of the breast and its natural form and prevents the psychological trauma associated with mastectomy. However, secondary reconstructions often have a higher satisfaction, since here no restitutio ad integrum is assumed. Alloplastic, i. e., implant-based, breast reconstruction and autologous breast reconstruction are complementary techniques. This article provides an overview of current options for breast reconstruction including patients' satisfaction and quality of life following breast reconstruction. Although immediate reconstruction is still the preferred choice of most patients and surgeons, delayed reconstruction does not appear to compromise clinical or patient-reported outcomes. Recent refinements in surgical techniques and autologous breast reconstruction include stacked-flaps, as well as microsurgical nerve coaptation to restore sensitivity, which lead to improved outcomes and quality of life. Nowadays Skin-sparing and nipple-sparing mastectomy, accompanied by improved implant quality, allows immediate prosthetic breast reconstruction as well as reemergence of the prepectoral implantation. The choice of breast reconstruction depends on the type of mastectomy, necessary radiation, individual risk factors, as well as the patient's habitus and wishes. Overall, recent developments in breast reconstruction led to an increase in patient satisfaction, quality of life and aesthetic outcome with oncological safety.

Skin Bank Establishment in Treatment of Severe Burn Injuries: Overview and Experience with Skin Allografts at the Vienna Burn Center.

Depending on their extent, burn injuries require different treatment strategies. In cases of severe large-area trauma, the availability of vital skin for autografting is limited. Donor skin allografts are a well-established but rarely standardized option for temporary wound coverage. Ten patients were eligible for inclusion in this retrospective study. Overall, 202 donor skin grafts obtained from the in-house skin bank were applied in the Department of Plastic and Reconstructive and Aesthetic Surgery, Medical University of Vienna. Between 2017 and 2022, we analysed the results in patient treatment, the selection of skin donors, tissue procurement, tissue processing and storage of allografts, as well as the condition and morphology of the allografts before application. The average Abbreviated Burn Severity Index (ABSI) was 8.5 (range, 5-12), and the mean affected total body surface area (TBSA) was 46.1% (range, 20-80%). In total, allograft application was performed 14 times. In two cases, a total of eight allografts were removed due to local infection, accounting for 3.96% of skin grafts. Six patients survived the acute phase of treatment. Scanning electron microscope images and histology showed no signs of scaffold decomposition and intact tissue layers of the allografts. The skin banking program and the application of skin allografts at the Vienna Burn Center can be considered successful. In severe burn injuries, skin allografts provide time by serving as sufficient wound coverage after early necrosectomy. Having an in-house skin banking program at a dedicated burn centre is particularly advantageous since issues of availability and distribution can be minimized. Skin allografts provide a reliable treatment option in patients with extensive burn injuries.

Impact of the COVID-19 pandemic on the epidemiology of severe burns : A single center study from a specialized burn center in Vienna.

INTRODUCTION: Currently, very little detailed information on the epidemiological distribution and specificities of severely burned patients during the coronavirus disease 2019 (COVID-19) pandemic is available. This retrospective study aims to describe and compare this specific patient population based on 114 patients who were treated between March 2019 and March 2021 at the Center for Severe Burn Injuries at the Medical University of Vienna. METHODS: To answer the research questions, a retrospective cohort study has been conducted over a period of 24 months, starting in March 2019 and ending in March 2021. To evaluate the epidemiological differences, the patients were divided into 2 observation periods of 12 months each. RESULTS: In the period from 12 March 2020 to 11 March 2021, a total of 62 patients were admitted to the Center for Severe Burn Injuries. In comparison, only 52 patients were admitted in the same period of the previous year, which corresponds to an increase of 19.2%. In addition, it was noted that during the 2019-2020 observation period, 27% of patients were female and 73% male, whereas during the pandemic the gender distribution was 42% female and only 58% male. During the pre-pandemic observational period, 13 out of 52 patients admitted died (25%), whereas during the pandemic, 17 out of 62 patients succumbed to their injuries (27%). CONCLUSION: Although the severity of the COVID-19 pandemic seems to be decreasing, especially due to the increasing availability of vaccines, there is a need for more data on the impact of the crisis on severely burned patients. In contrast to the current literature, we have seen a greater number of inpatient admissions to the Center for Severe Burn Injuries, as well as significant differences in gender distribution. Our data also suggest that the circumstances of the pandemic have no influence on the likelihood of survival for patients with severe burns.

Effects of metformin on human bone-derived mesenchymal stromal cell-breast cancer cell line interactions.

Metformin is used to treat patients with type 2 diabetes mellitus and was found to lower the incidence of cancer. Bone metastasis is a common impairment associated with advanced breast cancer. The present study investigated the effects of metformin on human bone-derived mesenchymal stromal cells (BM-MSC)-breast cancer cell line interactions. BM-MSCs grown from box chisels were tested for growth-stimulating and migration-controlling activity on four breast cancer cell lines either untreated or after pretreatment with metformin. Growth stimulation was tested in MTT tests and migration in scratch assays. Furthermore, the expression of adipokines of BM-MSCs in response to metformin was assessed using Western blot arrays. Compared to breast cancer cell lines (3.6 ± 1.4% reduction of proliferation), 500 µM metformin significantly inhibited the proliferation of BM-MSC lines (mean 12.3 ± 2.2 reduction). Pretreatment of BM-MSCs with metformin showed variable effects of the resulting conditioned media (CM) on breast cancer cell lines depending on the specific BM-MSC-cancer line combination. Metformin significantly reduced the migration of breast cancer cell lines MDA-MB-231 and MDA-MB-436 in response to CM of drug-pretreated BM-MSCs. Assessment of metformin-induced alterations in the expression of adipokines by BM-MSC CM indicated increased osteogenic signaling and possibly impairment of metastasis. In conclusion, the anticancer activities of metformin are the result of a range of direct and indirect mechanisms that lower tumor proliferation and progression. A lower metformin-induced protumor activity of BM-MSCs in the bone microenvironment seem to contribute to the positive effects of the drug in selected breast cancer patients.

Adipose-derived stromal/stem cells and extracellular vesicles for cancer therapy.

INTRODUCTION: Mesenchymal stromal/stem cells (MSCs) hold great perspective for the therapy of a host of diseases due to regenerative and anti-inflammatory properties by differentiation into diverse cell populations, homing to damaged tissue regions, paracrine effects, and release of extracellular vesicles. AREAS COVERED: This review describes the isolation, characterization, and potential use of MSCs and ADSCs for benign and malignant diseases. The MSCs may be administered as whole cells or in form of their secretome that is held responsible for most of their beneficial effects. A special constituent of the paracrine components are the extracellular vesicles (EVs) that carry a biologically potent cargo of proteins, cytokines, and RNA. EXPERT OPINION: The applications of MSCs and ADSCs are amply documented and have been investigated in preclinical models and many unregulated and a few controlled trials. Larger numbers of MSCs and ADSCs can be obtained for allogeneic transfer but imply difficulties including perseverance of the cells in vivo and possible differentiation into harmful cell types. MSC-derived cell-free preparations are easier to handle and manufacture for various applications. Especially, with the help of bioreactors, EVs can be obtained in excessive numbers and preloaded or charged with proteins, cytokines, and regulatory RNA specimen to treat inflammatory diseases and cancer.

Effects of metformin on adipose-derived stromal cell (ADSC) - Breast cancer cell lines interaction.

AIMS: Metformin is a clinical drug administered to patients to treat type 2 diabetes mellitus that was found to be associated with a lower risk of occurrence of cancer and cancer-related death. The present study investigated the effects of metformin on human adipose-derived stromal cells (ADSC) - breast cancer cell line interactions. MAIN METHODS: ADSCs grown from lipoaspirates were tested for growth-stimulating and migration-controlling activity on breast cancer cell lines after pretreatment with metformin. Furthermore, secreted proteins of ADSCs, phosphorylation of intracellular proteins and the effect of metformin on adipocytic differentiation of ADSCs were assayed. KEY FINDINGS: Compared to breast cancer cell lines (4.0 ± 3.5% reduction of proliferation), 2 mM metformin significantly inhibited the proliferation of ADSC lines (19.2 ± 8.4% reduction of proliferation). This effect on ADSCs seems to be mediated by altered phosphorylation of GSK-3, CREB and PRAS40. Furthermore, treatment with metformin abolished the induction of differentiation of three ADSC lines to adipocytes. 1 and 2 mM metformin significantly impaired the migration of breast cancer cell lines MDA-MB-231 and MDA-MB-436 in scratch assays. SIGNIFICANCE: Metformin showed low direct inhibitory effects on breast cancer cell lines at physiological concentrations but exerted a significant retardation of the growth and the adipocytic differentiation of ADSCs. Thus, the anticancer activity of metformin in breast cancer at physiological drug concentrations seems to be mediated by an indirect mechanism that lowers the supportive activity of ADSCs.

Interaction of Adipose-Derived Stromal Cells with Breast Cancer Cell Lines.

BACKGROUND: Assisted lipotransfer for breast reconstruction involves the isolation and supplementation of adipose-derived stromal cells. This procedure has raised concerns regarding safety with respect to promotion of tumor growth and relapse. Several in vitro and animal experimental studies have indicated increased survival, growth, and invasive characteristics of breast cancer cells on interaction with adipose-derived stromal cells. These results seem to be in poor concordance with clinical observations of a low rate of cancer recurrences after assisted lipotransfer. METHODS: The authors investigated the effects of adipose-derived stromal cells and adipose-derived stromal cells differentiated into adipocytes and fibroblasts on five breast cancer cell lines (i.e., T47D, MCF-7, BT20, MDA-MB-231, and ZR-75-1) and MCF-10A, a nonmalignant counterpart. RESULTS: Conditioned media of adipose-derived stromal cells stimulated the proliferation of breast cancer cell lines depending on the individual adipose-derived stromal cell-breast cancer cell line combination. Conditioned media of adipose-derived stromal cells differentiated into adipocytes gave a lower response, and conditioned media of fibroblasts were also active. A putative cancer stem cell-like phenotype was not increased by adipose-derived stromal cell-conditioned media, no physical interaction of cancer cells with adipose-derived stromal cells was detectable on scanning electron microscopy, and cell migration was not enhanced. Adipogenic differentiation of adipose-derived stromal cells indicated that hepatocyte growth factor, insulin-like growth factor-binding protein-3, insulin-like growth factor-binding protein-6, interleukin-6, CCL2/MCP-1, and macrophage colony-stimulating factor are not linked to the proliferative activity of conditioned media. CONCLUSION: The results indicate that the adipose-derived stromal cells used for assisted lipotransfer are not expected to increase the risk of tumor recurrence to a major degree in correspondence with the clinical observation of the affected breast cancer patients. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.