J S, A. | bioRxiv Science

bioRxiv2025

Evaluating the therapeutic efficacy of the US FDA-designated Orphan drug, uttroside B in impeding hepatocarcinogenesis via induction of immunogenic apoptosis, using a murine model of Aflatoxin B1-induced liver carcinogenesis

The sustained exposure to aflatoxin B1 (AFB1), a mycotoxin produced by Aspergillus sp., is one of the fundamental causes of hepatocellular carcinoma (HCC). We have previously documented the exceptional anti-HCC potential and pharmacological safety of uttroside B, a phytosaponin isolated in our lab (Utt-B). The current results indicate that Utt-B mitigates tumor development in mice that have been subjected to AFB1 exposure. Utt-B was found to be cytotoxic towards primary liver cancer cells cultured from mice bearing AFB1-induced liver tumors and the compound effectively prevented the formation of AfBO-DNA adducts in AFB1-induced liver tumors as well as primary liver cancer cells. In vitro studies revealed that treatment with Utt-B resulted in the induction of damage associated molecular patterns such as, ROS, HSP70 and inflammatory cytokines, IL-1{beta} and CXCL-10, suggesting the potential of Utt-B in triggering immunogenic cell death. Mechanistically, treatment with Utt-B enhances the antigen presentation potential, causes blockade of the major immune checkpoint molecules, namely, CTLA-4, PD-1, TIM-3, LAG-3 and TOX, and potentiates immunogenic apoptosis in the hepatic tumor microenvironment of mice pre-exposed to AFB1 via the activation of Zap70/Lck/GRZB signaling axis. Interestingly, it was also observed that Utt-B could abrogate the mutations induced by AFB1 in a concentration dependent manner. Taken together, the findings of the current study attest Utt-B as a propitious drug candidate against HCC.

cancer biology↗

bioRxiv2019

Regulation of Microtubule Disassembly by Spatially Heterogeneous Patterns of Acetylation

Microtubules (MTs) are bio-polymers, composed of tubulin proteins, involved in several functions such as cell division, transport of cargoes within cells, maintaining cellular structures etc. Their kinetics are often affected by chemical modifications on the filament known as Post Translational Modifications (PTMs). Acetylation is a PTM which occurs on the luminal surface of the MT lattice and has been observed to reduce the lateral interaction between tubulins on adjacent protofilaments. Depending on the properties of the acetylase enzyme TAT1 and the structural features of MTs, the patterns of acetylation formed on MTs are observed to be quite diverse. In this study, we present a multi-protofilament model with spatially heterogenous patterns of acetylation, and investigate how the local kinetic differences arising from heterogeneity affect the global kinetics of MT filaments. From the computational study we conclude that a filament with spatially uniform acetylation is least stable against disassembly, while ones with more clustered acetylation patterns may provide better resistance against disassembly. The increase in disassembly times for clustered pattern as compared to uniform pattern can be upto fifty percent for identical amounts of acetylation. Given that acetylated MTs affect several cellular functions as well as diseases such as cancer, our study indicates that spatial patterns of acetylation need to be focussed on, apart from the overall amount of acetylation.\n\nAuthor SummaryMicrotubules (MTs) form a crucial part of the cytoskeletal machinery which regulates several cellular processes. The basic building block of MTs are tubulin proteins. These proteins assemble in lateral and longitudinal directions to form a hollow cylindrical structure of a MT. There are chemical modifications on tubulin, known as Post Translational Modifications (PTMs), which affect the stability and dynamics of MT filaments. We computationally study how one such PTM, namely acetylation, affects the kinetics of disassembly of a MT filament. We propose a model which incorporates spatially heterogeneous patterns of acetylation on MT filament and study how they may regulate the disassembly times and velocities, a factor hitherto unexplored in studies. We conclude that there are significant differences of disassembly velocities and their fluctuations depending on the differnces in spatial patterns of acetylation.

biophysics↗