Biology subjects

Stepanov, I.

Publications and source records attributed to Stepanov, I..

3 recordsLinked to original sources

bioRxiv2026

The collective effect of non-nicotine constituents on the reinforcing and neuropharmacological effects of comprehensive cigarette smoke and electronic nicotine delivery system (ENDS) aerosol extracts in rats.

Tobacco product extracts containing nicotine and non-nicotine constituents are useful for understanding the collective role of these constituents in tobacco use disorder (TUD). However, few studies have used extracts with both water-soluble and non-water-soluble constituents with accompanying chemical analysis, or compared behavioral and neuropharmacological effects across product types. To address these limitations, we compared the relative abuse liability of cigarette smoke (CS) and electronic nicotine delivery system (ENDS) aerosol (EA) extracts to nicotine alone using intravenous self-administration in rats, and examined effects on nucleus accumbens (NAc) dopamine (DA) release and binding/function at nicotinic acetylcholine receptors (nAChRs) and other addiction-related receptors in vitro. CS extract contained higher levels of several behaviorally active non-nicotine constituents than EA extract. Both extracts produced a downward/leftward shift in the descending limb of the unit dose-response curve relative to nicotine alone, while only CS extract produced greater compensatory increases in responding compared to nicotine alone. Demand intensity (Q0) was lower for CS but not EA extract, relative to nicotine alone, whereas demand elasticity for both extracts was similar to nicotine alone. Stress-induced reinstatement was comparable between CS extract and nicotine alone but attenuated for EA extract. CS extract, but not EA extract, showed greater potency for 4{beta}2 nAChR activation and substantial binding across numerous non-nAChRs (DA, serotonergic, opioid) relative to nicotine alone at a high screening concentration. CS extract, but not nicotine alone, also inhibited cyclooxygenase (COX)-1 and -2 at smoking-relevant concentrations. There was no difference in NAc DA release between formulations. These findings indicate non-nicotine constituents contribute to certain reinforcing and neuropharmacological effects of CS, and to a lesser extent EA. Our finding of COX inhibition by CS extract warrants further investigation as a potential mechanism contributing to the effects of CS and TUD.

pharmacology and toxicology↗

bioRxiv2024

MICROMANIPULATION OF LIVE MICRODISSECTED TISSUES WITH A LOW-COST INTEGRATED ROBOTIC PLATFORM

The scarcity of human biopsies available for drug testing is a paramount challenge for developing new therapeutics, disease models, and personalized treatments. Microtechnologies that combine the microscale manipulation of tissues and fluids offer the exciting possibility of miniaturizing both disease models and drug testing workflows on scarce human biopsies. Unfortunately, these technologies presently require microfluidic devices or robotic dispensers that are not widely accessible. We have rapidly-prototyped an inexpensive platform based on an off-the-shelf robot that can microfluidically manipulate live microtissues into/out of culture plates without using complicated accessories such as microscopes or pneumatic controllers. The robot integrates complex functions with a simple, cost-effective and compact construction, allowing placement inside a tissue culture hood for sterile workflows. We demonstrated a proof-of-concept cancer drug evaluation workflow of potential clinical utility using patient tumor biopsies with multiple drugs on 384-well plates. Our user-friendly, low-cost platform promises to make drug testing of microtissues broadly accessible to pharmaceutical, clinical, and biological laboratories. TeaserA low-cost robot for handling microtissues and catalyzing their use in cancer drug evaluation and personalized oncology.

bioengineering↗

bioRxiv2024

Microdissected tumor cuboids: a microscale cancer model that retains a complex tumor microenvironment

To bridge the gap between bench and bedside, there is a need for more faithful models of human cancers that can recapitulate key features of the human tumor microenvironment (TME) and simultaneously facilitate large-scale drug tests. Our recently developed microdissection method optimizes the yield of large numbers of cuboidal microtissues (''cuboids '', ~(400 m)3 ) from a tumor biopsy. Here we demonstrate that cuboids from syngeneic mouse tumor models and human tumor biopsies retain a complex TME, making them amenable for drug and immunotherapy evaluation. We characterize relevant TME parameters, such as cellular architecture, cytokine secretion, proteomics profiles, and response to drug panels in multi-well arrays. Despite the cutting procedure and the time spent in culture (up to 7 days), the cuboids display strong cytokine expression and drug responses, including to immunotherapy. Overall, our results suggest that cuboids could provide essential therapeutic information for personalized oncology applications and could help the development of TME-dependent therapeutics and cancer disease models, including for clinical trials.

cancer biology↗