Noninvasive morpho-molecular imaging reveals early therapy-induced senescence in human cancer cells

Abstract

Anticancer therapy screening in vitro identifies additional treatments and improves clinical outcomes. Systematically, although most tested cells respond to cues with apoptosis, an appreciable portion enters a senescent state, a critical condition potentially driving tumor resistance and relapse. Conventional screening protocols would strongly benefit from prompt identification and monitoring of therapy-induced senescent (TIS) cells in their native form. We combined complementary all-optical, label-free, and quantitative microscopy techniques, based on coherent Raman scattering, multiphoton absorption, and interferometry, to explore the early onset and progression of this phenotype, which has been understudied in unperturbed conditions. We identified TIS manifestations as early as 24 hours following treatment, consisting of substantial mitochondrial rearrangement and increase of volume and dry mass, followed by accumulation of lipid vesicles starting at 72 hours. This work holds the potential to affect anticancer treatment research, by offering a label-free, rapid, and accurate method to identify initial TIS in tumor cells.

Innovative Approaches for Drug Discovery: Quantifying Drug Distribution and Response with Raman Imaging

“…In 2023, Bresci et al combined CARS and SRS with quantitative phase microscopy to investigate cell senescence. 162 The authors found alterations in cell volume, thickness, and dry mass in the HepG2 cells following deferoxamine or radiation treatment. Lipid droplet characteristics, such as volume and dry mass, also exhibited notable changes during treatment, indicating senescence manifestations as early as 24 h after treatment.…”

“…Both cell lines showed a significant reduction in cytoplasmic dry mass and protein concentrations in senescence compared with proliferating interphase cells. In 2023, Bresci et al combined CARS and SRS with quantitative phase microscopy to investigate cell senescence . The authors found alterations in cell volume, thickness, and dry mass in the HepG2 cells following deferoxamine or radiation treatment.…”

Pinpointing Fat Molecules: Advances in Coherent Raman Scattering Microscopy for Lipid Metabolism

“…CARS imaging coupled with TPEF imaging also allows for simultaneous visualization of the optical redox ratio (ORR = FAD + / (NADH + FAD + )) and lipids in primary mammary epithelial cells during acini formation (Figure B). A similar approach was adopted to study mitochondrial morphology and lipid accumulation in cancer cells during therapy-induced senescence (Figure C). Moreover, a multimodal nonlinear optical system combining SRS, SHG, and TPEF was employed to simultaneously visualize protein, saturated lipid, unsaturated lipid, de novo synthesis of protein and lipid, collagen, and ORR; such multichannel imaging represents a sensitive approach with subcellular resolution to characterize cancer subtypes …”

Nanoplastics Penetrate Human Bronchial Smooth Muscle and Small Airway Epithelial Cells and Affect Mitochondrial Metabolism

“…As light traverses through a sample, the various constituents scatter light differently based on their refractive index. By rotating the imaging beam around the sample in a full circle, a series of holograms are collected from multiple perspectives [28]. These collected two-dimensional (2D) holographic images, taken from different angles of illumination, are then compiled to construct a 3D RI tomogram, offering a more comprehensive view of the sample's internal structure [29].…”