# Discovery and Mechanistic Characterization of New Cytotoxic Agents from Marine Cyanobacteria

> **NIH NIH F31** · UNIVERSITY OF FLORIDA · 2022 · $44,681

## Abstract

Abstract
Cancer is a major health problem worldwide and is the second leading cause of death in the United States.
Despite the significant advances in cancer research, available therapies still encounter limitations such as
resistance, specificity and toxicity, which urgent the discovery of new anticancer agents. Several studies
exemplified marine cyanobacteria's role in providing chemically diverse potent cytotoxic agents that act via
novel mechanisms. Harnessing the structural space reproduced by marine cyanobacteria in an efficient
planned strategy would significantly impact the cancer research field. Therefore, we screen cyanobacterial
samples for new/novel cytotoxins and complement our discovery with comprehensive mechanistic studies to
assign the therapeutically relevant biological targets. Specifically, samples derived from morphologically and
phylogenetically novel cyanobacteria are prioritized for extraction. Extracts are subjected to cancer cell viability
assay guided fractionation, coupled with LCMS and NMR dereplication strategies. Structures will be
determined using NMR and mass spectrometry. Compounds with intriguing structural novelty and potent or
selective activity are subjected to mechanistic characterization. An unbiased assessment of cellular targets is
necessary to mine for novel biology/targets. Therefore, we implement universal approaches that could pinpoint
perturbed biological pathways and potential molecular targets. In parallel, targeted approaches are employed if
structural features of the identified cytotoxin suggest potential pharmacophores with known interacting
proteins. We successfully identified targets of the antifungal cytotoxin amantelide A using chemogenomic
profiling and targeted approaches. In addition, through the use of an isogenic screening system, we built in
selectivity screening in the discovery process to determine if identified new cytotoxins are inhibitors of the
oncogenic KRAS and HIF pathways, since these pathways are activated in cancer compared with normal cells.
The proposed work will identify new/novel cytotoxic agents that would serve leads to new anticancer therapies.
Besides, their assessment as chemical probes would widen our breadth of many biological processes. Finally,
this study has the potential to inform new biological target space, which is of tremendous value to cancer
research.

## Key facts

- **NIH application ID:** 10533271
- **Project number:** 5F31GM143915-02
- **Recipient organization:** UNIVERSITY OF FLORIDA
- **Principal Investigator:** Lobna Elsadek
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $44,681
- **Award type:** 5
- **Project period:** 2021-08-16 → 2023-08-15

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10533271

## Citation

> US National Institutes of Health, RePORTER application 10533271, Discovery and Mechanistic Characterization of New Cytotoxic Agents from Marine Cyanobacteria (5F31GM143915-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10533271. Licensed CC0.

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