Dumbrava, Mihai

Abstract Cancer can recur when a subset of tumor cells, denoted here as persister cells, are able to survive therapy and re-enter the cell cycle. The precise mechanisms that confer the persister state and whether it is characteristic of a subgroup of cells or arises from multiple cellular lineages remain poorly understood. We hypothesize that an epigenetic signature underlies the drug-tolerant persister state, characterized by transcriptional and chromatin accessibility changes that promote survival of residual cancer following chemotherapy. To identify clinically relevant features of persister cells in untreated tumors and residual disease, we performed single-cell multiomic profiling (snRNA+snATAC) on a cohort of non-malignant fallopian tube, treatment-naïve, and neoadjuvant chemotherapy (NACT)-treated high-grade serous ovarian cancer (HGSOC) samples. We identified differences in gene expression and open chromatin between naïve and residual patient tumors following chemotherapy. Although only a small proportion of the differentially expressed genes enriched in residual HGSOC overlapped with established gene sets for chemo-response and patient prognosis, the epigenomic analysis revealed activity of several DNA-binding factors that are both enriched upon chemotherapy and also high in resistant tumors prior to treatment. From this analysis, we identified an epigenetic signature that precedes expression and defines the persister state. This epigenetic signature also correlated with chemotherapy sensitivity and resistance using patient-derived xenograft models of HGSOC. Gene regulatory networks driven by the persister signature are involved in the activation of oncogenic pathways, including changes to the cell cycle promoting quiescence and stress response. Further study of the persister cells identified by this epigenetic signature may increase understanding of the mechanisms underlying persister cell survival and reveal new vulnerabilities that could be exploited to delay or prevent cancer recurrence.

Introduction: Monoclonal gammopathy of renal significance (MGRS) is characterized by clonal cell deposition of monoclonal immunoglobulin causing renal manifestations without overt malignancy. MIDD is a subtype of MGRS characterized by deposition of monoclonal light (LCDD), heavy chains (HCDD), or both (LHCDD) along the renal glomerular and tubular basement membranes. Virtually all organs can be involved, and if left untreated, MIDD can progress to MM and end stage renal disease. Although these patients classically did not receive treatment, current MIDD management is primarily focused on controlling the underlying clonal plasma cell disorder. Case description: We present a 56-year-old male with atypical MIDD treated successfully with plasma cell directed therapy consisting of daratumumab, cyclophosphamide, bortezomib, and dexamethasone (DARA-CYBOR-D). Despite a primary diagnosis of diabetic kidney disease, renal biopsy suggested myeloma-related MIDD based on linear immunofluorescent staining for IgG and kappa light chains along the tubular and glomerular basement membranes. Notably there were no electron dense deposits in the mesangium or tubular basement membranes typical to MIDD electron microscopy. Despite the presentation of MIDD on IF only, DARA-CYBOR-D treatment led to hematologic and renal improvement and remission from MIDD, with a GFR increase from 22 to 59 mL/min/BSA and a drop in urine protein from up to 9 to 0.6 g/dL. Conclusions: In conclusion, our case illustrates the efficacy of the DARA-CYBOR-D regimen in a patient with IF-only MIDD. We highlight the importance of obtaining a kidney biopsy when there are other potential causes for real decline and enhance our understanding of pathological and clinical spectrum of MIDD.

AbstractPatient‐derived cancer organoids (PDOs) hold considerable promise for personalizing therapy selection and improving patient outcomes. However, it is challenging to generate PDOs in sufficient numbers to test therapies in standard culture platforms. This challenge is particularly acute for pancreatic ductal adenocarcinoma (PDAC) where most patients are diagnosed at an advanced stage with non‐resectable tumors and where patient tissue is in the form of needle biopsies. Here the development and characterization of microfluidic devices for testing therapies using a limited amount of tissue or PDOs available from PDAC biopsies is described. It is demonstrated that microfluidic PDOs are phenotypically and genotypically similar to the gold‐standard Matrigel organoids with the advantages of 1) spheroid uniformity, 2) minimal cell number requirement, and 3) not relying on Matrigel. The utility of microfluidic PDOs is proven by testing PDO responses to several chemotherapies, including an inhibitor of glycogen synthase kinase (GSKI). In addition, microfluidic organoid cultures are used to test effectiveness of immunotherapy comprised of NK cells in combination with a novel biologic. In summary, our microfluidic device offers considerable benefits for personalizing oncology based on cancer biopsies and may, in the future, be developed into a companion diagnostic for chemotherapy or immunotherapy treatments.

The snATAC + snRNA platform allows epigenomic profiling of open chromatin and gene expression with single-cell resolution. The most critical assay step is to isolate high-quality nuclei to proceed with droplet-base single nuclei isolation and barcoding. With the increasing popularity of multiomic profiling in various fields, there is a need for optimized and reliable nuclei isolation methods, mainly for human tissue samples. Herein we compared different nuclei isolation methods for cell suspensions, such as peripheral blood mononuclear cells (PBMC, n = 18) and a solid tumor type, ovarian cancer (OC, n = 18), derived from debulking surgery. Nuclei morphology and sequencing output parameters were used to evaluate the quality of preparation. Our results show that NP-40 detergent-based nuclei isolation yields better sequencing results than collagenase tissue dissociation for OC, significantly impacting cell type identification and analysis. Given the utility of applying such techniques to frozen samples, we also tested frozen preparation and digestion (n = 6). A paired comparison between frozen and fresh samples validated the quality of both specimens. Finally, we demonstrate the reproducibility of scRNA and snATAC + snRNA platform, by comparing the gene expression profiling of PBMC. Our results highlight how the choice of nuclei isolation methods is critical for obtaining quality data in multiomic assays. It also shows that the measurement of expression between scRNA and snRNA is comparable and effective for cell type identification.

Post-transplant lymphoproliferative disorder (PTLD) is a complication of immunosuppressive therapy following solid organ or hematopoietic cell transplantation. Initial treatment typically includes a reduction of immunosuppression with or without rituximab. However, the optimal therapy for PTLD with plasmacytic differentiation is unclear. We present 3 cases of pediatric patients with plasmacytic PTLD. Two patients received a standard rituximab-based approach and relapsed, prompting additional chemotherapy. The third patient was treated with a novel regimen of bortezomib, dexamethasone, and daratumumab. This regimen was safe, well-tolerated, and resulted in a 2-year remission. Larger studies are needed to further explore this regimen.

AbstractBackgroundWith an increasing demand of aesthetic soft‐tissue filler treatments, the occurrence of adverse events rises likewise. An optimized injection algorithm adapted to product characteristics (eg, rheology) of the soft‐tissue filler is crucial in order to ensure satisfying clinical outcomes and high patient safety.ObjectiveTo identify a subjective feedback mechanism for the avoidance of adverse events after soft‐tissue filler injection procedures.MethodsA retrospective data analysis of n = 387 aesthetic treatments performed on n = 291 patients (4 males, 287 females) with different soft‐tissue fillers with regard to loss of volume (filling effect), injected layer, injectability (“ease of injection”), injected volume, and injection technique was conducted.ResultsThe subjectively perceived injectability during the injection process was statistically significantly related to G‐Prime value with rs = 0.101 with p = 0.048, indicating an increased difficulty while injecting products with higher G‐Prime. The occurrence of adverse events was also statistically significantly related to the injectability: injections with increased subjectively perceived difficulty showed increasing odds of developing adverse events by OR 0.157 with p = 0.002.ConclusionInjections that were subjectively more difficult to perform are more likely to develop adverse events. Respecting the layered arrangement of the face, the recommended and approved depth and facial region for each specific treatment enable practitioners to achieve satisfying outcomes while keeping the rate of adverse events low.

AbstractBackgroundUnderstanding the mobility of the midface and the separate contributions of the superficial and deep fat compartments is essential for natural esthetic outcomes following soft tissue filler or fat grafting procedures. A study was designed that used ultrasound imaging to demonstrate in vivo visualization and quantification of distances and movements in the midface.MethodsA total of 48 midfaces of 24 healthy Caucasian volunteers, all naïve of esthetic procedures, (22 females; 46.85 (9.8) years; 22.83 (3.1) kg/m2) were scanned using 18 MHz ultrasound imaging. Distances between bony landmarks (inferior orbital rim, infraorbital foramen) were used as markers to measure the cranial movement of the superficial (superficial nasolabial and superficial medial cheek fat compartment) and the deep (deep pyriform space, deep medial check fat compartment, deep lateral cheek fat compartment) midfacial fat compartments between resting and smiling facial position.ResultsThe superficial midfacial fat compartment moved, on average, 3.7 mm (p < 0.001) cranially, whereas the deep midfacial fat compartments moved, on average, 0.1 mm (p > 0.05) during smiling. No gender differences in mobility were identified (p > 0.05).ConclusionThe results obtained are in line with previous cadaveric investigations and revealed, in a highly statistically significant fashion, that the superficial midfacial fat compartments move in cranial direction whereas the deep fat compartment did not display similar positional changes. These results help to guide facial injectable treatments and to understand why, in the midface, a deep supraperiosteal approach should be favored when augmenting the deep midfacial fat compartments.