Biology subjects

Popova, L.

Publications and source records attributed to Popova, L..

3 recordsLinked to original sources

bioRxiv2026

Establishment of a patient-derived adrenocortical carcinoma 3D tumor construct platform for evaluation of therapeutic strategies

Adrenocortical carcinoma (ACC) is an under-studied, aggressive cancer of the adrenal glands where surgical resection is currently the only effective curative option. However, after surgery the majority of patients experience tumor progression. The median overall survival of 12 months has not improved since approval of mitotane in 1970. The lack of effective therapies in ACC is partially due to the lack of preclinical models that accurately represent human ACC. Most attempts to generate ACC cell lines or animal models have been unsuccessful. The few existing models do not adequately reflect the oncogenic signaling pathways or intratumoral heterogeneity of human ACC. These limited model systems have hindered identification of drivers of tumor progression and immune escape mechanisms, thereby limiting development and testing of novel therapeutic approaches such as targeted therapies or immunotherapies. We developed human ACC patient-derived tumor constructs (PTCs) encapsulated in synthetic extracellular matrix. Our ACC PTCs exhibit hallmarks of ACC: proliferation, expression of key ACC biomarkers, such as SF1, and production of cortisol. We provide characterization in the form of immunofluorescence staining for ACC biomarkers, and confirmation of PTC proliferation and cortisol production - a hallmark of ACC. We then demonstrate the utility of ACC PTCs for evaluation of chemotherapies currently used clinically (mitotane) with and without experimental cocktails of etoposide, doxorubicin, and cisplatin, experimental targeted therapies, and cellular immunotherapies, primarily in the form of natural killer (NK) cell therapy. In particular, the latter - cellular immunotherapies - are cutting edge studies demonstrating potential to evaluate immunotherapies in ACC clinical scenarios. Together these data provide evidence that patient-derived ACC models can serve as an important tool for identification of future points of intervention and testing of novel therapeutic strategies to improve ACC clinical care.

cancer biology↗

bioRxiv2025

The acetylation of the histone-like protein HBsu at specific sites alters gene expression during sporulation in Bacillus subtilis

Sporulation is an adaptive response to starvation in bacteria that consists of a series of developmental changes in cellular morphology and physiology, leading to the formation of a highly resistant endospore. In Bacillus subtilis, there is an intricate developmental program which involves the precise coordination of gene expression and ongoing morphological changes to yield the mature spore. The histone-like protein HBsu is involved in proper spore packaging and compaction of the chromosomal DNA. Previously, we found that the acetylation of different lysine residues on HBsu impairs sporulation frequency and spore resistance properties. One mechanism by which HBsu influences the process of sporulation could be through the regulation of gene expression. To test this idea, we performed RT-qPCR to analyze gene expression throughout the sporulation process in wildtype and seven acetylation-mimicking (glutamine substitutions) mutant strains. Acetylation of HBsu at K41 increased the expression of key early and late sporulation genes, especially during the later stages. For example, overexpression of {sigma}F and {sigma}G drive expression of their regulon members at inappropriate times. These findings suggest that K41 acetylation activates gene expression and might represent an "on-off" switch for important regulatory factors as cells transition from early to late phases. The gene expression profiles of hbsK3Q, hbsK37Q, hbsK75Q, hbsK80Q, and hbsK86Q mutants were largely unchanged, but did have significant reductions of key late sporulation proteins, which could explain the observed defects in spore resistance properties. We propose that acetylation of HBsu at specific sites directly regulates gene expression during sporulation and this is required for proper timing and coordination.

microbiology↗

bioRxiv2023

A 3D adrenocortical carcinoma tumor platform for preclinical modeling of drug response and matrix metalloproteinase activity

Adrenocortical carcinoma (ACC) has a poor prognosis, and no new drugs have been identified in decades. The absence of drug development can partly be attributed to a lack of preclinical models. Both animal models and 2D cell cultures of ACC fail to accurately mimic the disease, as animal physiology is inherently different than humans, and 2D cultures fail to represent the crucial 3D architecture. Organoids and other small 3D in vitro models of tissues or tumors can model certain complexities of human in vivo biology; however, this technology has largely yet to be applied to ACC. In this study, we describe the generation of 3D tumor constructs from an established ACC cell line, NCI-H295R. NCI-H295R cells were encapsulated to generate 3D ACC constructs. Tumor constructs were assessed for biomarker expression, viability, proliferation, and cortisol production. In addition, matrix metalloproteinase (MMP) functionality was assessed directly using fluorogenic MMP-sensitive biosensors and through infusion of NCI-H295R cells into a metastasis-on-a-chip microfluidic device platform. ACC tumor constructs showed expression of biomarkers associated with ACC, including SF-1, Melan A, and inhibin . Treatment of ACC tumor constructs with chemotherapeutics demonstrated decreased drug sensitivity compared to 2D cell culture. Since most tumor cells migrate through tissue using MMPs to break down extracellular matrix, we validated the utility of ACC tumor constructs by integrating fluorogenic MMP-sensitive peptide biosensors within the tumor constructs. Lastly, in our metastasis-on-a-chip device, NCI-H295R cells successfully engrafted in a downstream lung cell line-based construct, but invasion distance into the lung construct was decreased by MMP inhibition. These studies, which would not be possible using 2D cell cultures, demonstrated that NCI-H295R cells secreted active MMPs that are used for invasion in 3D. This work represents the first evidence of a 3D tumor constructs platform for ACC that can be deployed for future mechanistic studies as well as development of new targets for intervention and therapies. SignificanceThe paucity of preclinical research models has contributed to lack of progress in treatment of adrenocortical carcinoma (ACC). Three-dimensional modeling of ACC may provide novel insights for preclinical studies and advance ACC research.

cancer biology↗