Ovarian cancer (OC) remains one of the most lethal gynaecological malignancies, which is mainly due to late diagnosis, high frequency of metastasis, and the risk of developing resistance to systemic therapy. In recent years, exosomes-small extracellular vesicles (EVs) secreted by cancer cells and components of the tumour microenvironment (TME)-have been identified as potential mediators of OC progression. Exosomes participate in intercellular communication and enable the transfer of RNA, proteins, and lipids. These vesicles may modulate the immune response, promote angiogenesis, remodel the extracellular matrix, and drive epithelial-mesenchymal transitions. Exosomes also appear to play a role in the development of drug resistance via direct transfer of resistance factors or indirect modification of TME. In this review article, we summarise current knowledge on the biological role of exosomes in OC pathogenesis. We also discuss their possible diagnostic, prognostic, and therapeutic relevance. The properties and composition of exosomes make them promising noninvasive liquid biomarkers and convenient carriers for anticancer drugs. However, to fully exploit their potential, further large-scale preclinical and clinical studies are required, which should focus primarily on standardising research methods and assessing the safety and efficacy of exosome-based diagnostic and therapeutic methods.

Synthesis of bifunctional cytisine–squaramide derivatives bearing a single amino acid moiety has revealed an unexpected and intriguing chemical challenge. During modification of cytisine squaramates with α-amino acids, base-sensitive amido esters readily underwent hydrolysis, forming poorly soluble amido-acid side products that resisted standard purification and initially obscured their identity. Persistent observation of these elusive precipitates prompted a deliberate co-crystallization approach, which unambiguously revealed their supramolecular nature using single-crystal X-ray diffraction. With this insight, optimized purification strategies allowed isolation of analytically pure Cyt-SQ-OH and its derivatives, which were characterized by complementary spectroscopic techniques, X-ray crystallography and computational studies. Furthermore, the DFT-optimized parameters of all compounds were determined, providing additional insight into their structural and electronic properties. This work highlights the interplay between reactivity, solubility, and supramolecular assembly in cytisine–squaramide-amino acid hybrids, providing a robust platform for future exploration of multifunctional conjugates with potential applications in medicinal chemistry, molecular recognition, and materials science.

Ovarian cancer (OvCa) remains a major therapeutic challenge due to limited treatment options and frequent late-stage diagnosis, which contribute to high recurrence rates and mortality. Advances in synthetic organic chemistry and the development of novel oncology-targeted molecules offer promising new directions. In this study, we aimed to evaluate salinomycin (SAL) and its semisynthetic derivatives as potential candidates for OvCa therapy. Among the synthesized C20 SAL derivatives, we selected compound 8, featuring a triphenylphosphonium (TPP+) motif and exhibiting a cytotoxicity profile comparable to that of the parent molecule, for further investigation of its anticancer mechanism of action. In combination with carboplatin (CBP), we investigated the interactions and effects on cell viability, cell cycle distribution, reactive oxygen species (ROS) production, mitochondrial membrane potential, and autophagy markers. Our findings indicated that SAL and 8 share a similar mechanism of action, inducing G0/G1 cell cycle arrest, reducing ROS production, and disrupting mitochondrial integrity, thereby promoting autophagy rather than classical cell death pathways in the tested OvCa cell lines. These results suggest that the TPP+-conjugated SAL derivatives may be promising therapeutic candidates for the management of OvCa, either as monotherapy or in combination with CBP and related drugs.

Herein, we report the application of the Ugi four-component reaction as an efficient and versatile strategy for the synthesis of macrocyclic derivatives of monensin. The approach enables the incorporation of a peptidomimetic linker, significantly modulating the biological and cation complexation properties of the obtained compounds. All derivatives were obtained in crystalline form, allowing unambiguous structural elucidation by single-crystal X-ray diffraction, which revealed macrocyclic architectures stabilized by intramolecular hydrogen bonding.

Our team previously demonstrated that salinomycin (SAL) robustly upregulates CD20 antigen levels on the surface of malignant B cells (Torun et al., 2025, Haematologica). Both monoclonal antibodies (mAbs) and cellular therapies target CD20 to eliminate malignant B cells. Therefore, the upregulation of CD20 would further enhance the therapeutic efficacy of monoclonal antibodies (mAbs) and CAR-T cells. In the current study, we selected several SAL derivatives based on their CD20-upregulating activity and tested their ability to enhance immunotherapy in vitro and in preclinical animal models. B-cell-derived malignant cells, SCID and NSG mice, and a library of SAL derivatives. Flow cytometry, anti-CD20 CAR-T generation, complement- and NK cell-dependent cytotoxicity assays, RNA-seq, RT-PCR, Western blotting, and CRISPR/Cas9 gene editing. Using flow cytometry screening, we selected several SAL derivatives with modifications in chemical structure (positions C1 and C20) that induced CD20 upregulation more efficiently than the original SAL. The in vitro experiments confirmed that these SAL derivatives were more efficient than SAL in inducing the killing of malignant B cells via the action of anti-CD20 therapeutic mAbs (complement- and NK cell-dependent cytotoxicity assays, CDC and ADCC, respectively) and CAR-T cells. Of note, the application of selected SAL derivatives in combination with the anti-CD20 therapeutic mAb, Rituximab, significantly extended the life of SCID mice with Burkitt’s lymphoma. To characterize the critical molecular events mediating the enhanced CD20 upregulation, we analyzed the RNA-seq data. In addition to the suppression of c-Myc and FOXO (previously reported by us in Torun et al., 2025, Haematologica), we found that the regulation of NFY-A/B/C transcription factors also plays a key role. CRISPR/Cas9-mediated knockout of NFY factors led to robust upregulation of CD20, indicating that NFY factors are significant negative regulators of this antigen. Our findings from in vitro assays and preclinical animal models provide a rationale for the clinical evaluation of SAL derivatives to improve treatment outcomes in patients with B-cell-derived malignancies. National Science Centre (NCN, Poland; 2019/35/B/NZ5/01445 to BP, 2020/39/B/NZ6/03513 to AZ), Medical Research Agency (ABM, Poland; 2024/ABM/03/KPO/KPOD.07.07-IW.07-0218/24) under the National Recovery and Resilience Plan (KPO), and Polish National Agency For Academic Exchange (NAWA; BPI/PST/2024/1/00110 to BP and AZ). Aleksandra Zdanowicz, Bhaskar Pradhan, Marta Jedrzejczyk, Adam Huczynski, Abdessamad Zerrouqi, Beata Pyrzynska. NFY-mediated regulation of CD20 is targeted by novel salinomycin derivatives to potentiate anti-CD20 immunotherapy [abstract]. In: Proceedings of the AACR Immuno-Oncology Conference (AACR IO): Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2026 Feb 18-21; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2026;14(2 Suppl):Abstract nr B008.

Natural products have traditionally played a pivotal role in the field of drug discovery, offering chemists and biologists an abundant source of inspiration regarding a variety of structures and functions. Notably, the identification of anticancer activities in several renowned antibiotics over the past years has opened new therapeutic avenues and highlighted the significance of drug repurposing strategies. In this context, we provide a comprehensive review of monensin (MON), a natural polyether ionophore antibiotic, delineating its biological and chemical properties and summarizing various approaches, particularly structural modifications, employed to explore its potential in cancer-related research. Preclinical investigations have demonstrated that MON effectively targets a wide range of cancer cells, including those exhibiting stem cell-like properties. Its combination with standard chemotherapeutics appears especially promising in this context. While nanotechnology may help address some clinical limitations of MON, extensive research over the past decade has focused on the derivatization of its most reactive functional groups, such as C1 carboxyl and C26 hydroxyl, to produce semisynthetic derivatives with improved anticancer activity compared to the native structure. We hope that the findings presented in this review will inspire and motivate researchers to initiate, sustain, and broaden studies of the off-label use of MON in the ongoing battle against cancer.

Herein, we report the application of the Ugi four-component reaction as an efficient and versatile strategy for the synthesis of macrocyclic derivatives of monensin. The approach enables the incorporation of a peptidomimetic linker, significantly modulating the biological and cation complexation properties of the obtained compounds. All derivatives were obtained in crystalline form, allowing unambiguous structural elucidation by single-crystal X-ray diffraction, which revealed macrocyclic architectures stabilized by intramolecular hydrogen bonding.

Objectives/Goals: Monensin is FDA approved for use in veterinary medicine. Recent studies pointed to its potent anticancer activity. Since de novo drug discovery process typically takes 10 to 15 years and requires an investment of approximately $1.3 to $3 billion, drug repositioning can bypass several steps in this process and increase the potential for success. Methods/Study Population: Cell viability assays were conducted on human MDA-MB-231, MDA-MB-468, and MCF10A breast cancer cell lines and mouse EO771 and 4T1 breast cancer cell lines. MDA-MB-231 cell line was used in all the studies unless specified otherwise. Time course levels of Bcl-2, Bak, p62, and LC3II were assessed via Western blotting with GAPDH as a loading control. Proteomics analysis was conducted by the IDEA National Resource for Quantitative Proteomics. Time course levels of major histocompatibility complex (MHC) I and II and calreticulin were evaluated using flow cytometry. At least three biological replicates have been conducted for each experiment. Results/Anticipated Results: Monensin and several of its novel analogs were potent toward human and mouse breast cancer cell lines. Furthermore, they induced apoptotic cell death as evidenced by Annexin V/PI assay, downregulation of Bcl-2, and upregulation of Bak in MDA-MB-231 cells. Proteomics analysis revealed that several molecular pathways related to MHC class I and II antigen presentation were significantly altered following treatment with these compounds. Additionally, monensin and its analogs significantly increased the expression of MHC class I and II. Our studies also showed that monensin and its analogs increase the surface calreticulin levels. Treatment of MDA-MB-231 cells with these compounds also resulted in an increase in p62 and LC3II expression, suggesting a disruption of the autophagic process. Discussion/Significance of Impact: These results suggest that monensin and its analogs not only exhibit anti-breast cancer cell activity but also modulate immune-related pathways. By disrupting autophagy and enhancing calreticulin levels, these compounds may potentiate antitumor immune responses, providing a promising avenue for drug repositioning in cancer therapy.

Derivatives of squaric acid are valuable building blocks with promising applications in the investigation of various bioactivities. In this study, we focus on squaramides functionalized with the (-)-cytisine moiety, an alkaloid known for its bioactivity as a nicotinic acetylcholine receptor agonist and its application in nicotine addiction treatment. Reactions of cytisine-monosquarate with several amines, such as ammonia, propargylamine, and morpholine, led to the formation of novel conjugates of cytisine-squaramides. Additionally, squaramide containing two cytisine moieties was synthesized via the reaction of diethyl squarate with cytisine at a 1:2 molar ratio. All obtained squaramides were thoroughly characterized by MS, FT-IR, and NMR methods and by single-crystal X-ray diffraction analysis. To gain deeper insights into their structural properties and intermolecular interactions, geometry optimizations were performed using DFT calculations, complemented with 3D molecular electrostatic potential maps.

Monensin ( MON ) is a polyether ionophore antibiotic of natural origin and is an FDA-approved drug for veterinary use. Recent studies have highlighted its potential anti-cancer activity in various in vitro and in vivo models. In this study, we evaluated the anti-breast cancer activity of MON and 37 synthetic analog compounds using cell monolayer and organoid models. Through a mini-ring cell viability assay, several compounds were identified that were more potent and selective against breast cancer cells compared to non-cancerous cells, surpassing the activity of parent MON . MON and these compounds induced significant DNA fragmentation, reduced cell migration, and downregulated SOX2 expression. Furthermore, MON and the most potent analog, compound 12 , reduced the percentage of CD44 + /CD24 -/low stem-like cells and diminished cell self-renewal properties. Proteomics analyses revealed that several pathways, including extracellular matrix organization, were significantly dysregulated by MON and compound 12 in breast cancer cells. Among these, TIMP2, a protein associated with the suppression of tumor growth and metastasis, was identified as one of the most prominently upregulated proteins by MON and compound 12 in MDA-MB-231 cells. This finding was also validated in other breast cancer and melanoma cell lines. To simulate breast cancer metastasis to the brain, a human Hybrid Organoid System: Tumor in Brain Organoid (HOSTBO) model was developed. MON and compound 12 significantly reduced Ki-67 expression within the HOSTBOs, and compound 12 significantly downregulated SOX2 expression. Collectively, MON and compound 12 significantly reduced the proliferation of breast cancer stem-like cells in the organoid models, inhibited their migration, and dysregulated markers associated with stemness, demonstrating their potential as anti-metastatic agents and warranting further clinical development. Abstract Figure:

Salinomycin and monensin represent a class of natural ionophore antibiotics with strong anticancer properties. In this paper we report on chemical modification of these compounds by conjugation with phosphonium cations for targeting conjugates to the mitochondria of cancer cells. Our findings indicate that this approach yields conjugates with enhanced anticancer activity and selectivity, outperforming not only the parent compounds but also the widely used chemotherapeutic agent, doxorubicin. Comprehensive biological and biophysical analyses proved that the conjugates target the mitochondria in cancer cells, with some of the derivatives additionally promoting generation of mitochondrial reactive oxygen species (mtROS). This targeted strategy holds significant promise for the development of effective mitochondrial-targeted novel anticancer agent.

Tea is a significant source of flavonoids in the diet. Due to different production processes, the amount of bioactive compounds in unfermented (green) and (semi-)fermented tea differs. Importantly, green tea has a similar composition of phenolic compounds to fresh, unprocessed tea leaves. It consists primarily of monomeric flavan-3-ols, known as catechins, of which epigallocatechin gallate (EGCG) is the most abundant. Thanks to its antioxidant, antiproliferative, and antiangiogenic properties, EGCG has attracted the scientific community’s attention to its potential use in preventing and/or combating cancer. In this review article, we summarize the literature reports found in the Google Scholar and PubMed databases on the anticancer effect of EGCG on selected malignant neoplasms in women, i.e., breast, cervical, endometrial, and ovarian cancers, which have been published over the last two decades. It needs to be emphasized that EGCG concentrations reported as effective against cancer cells are typically higher than those found in plasma after polyphenol administration. Moreover, the low bioavailability and absorption of EGCG appear to be the main reasons for the differences in the effects between in vitro and in vivo studies. In this context, we also decided to look at possible solutions to these problems, consisting of combining the polyphenol with other bioactive components or using nanotechnology. Despite the promising results of the studies conducted so far, mainly in vitro and on animal models, there is no doubt that further, broad-based activities are necessary to unequivocally assess the potential use of EGCG in oncological treatment to combat cancer in women.

Cytisine, a naturally occurring alkaloid and partial agonist of nicotinic acetylcholine receptors (nAChRs), has long been used as a smoking cessation aid and serves as the pharmacophore for varenicline. Recent research has expanded its therapeutic scope to neurodegenerative and neurological disorders, motivating the development of new cytisine derivatives. Among these, N-propargylcytisine combines the biological activity of the parent compound with the synthetic versatility of the terminal alkyne group. Herein, we report the synthesis and characterization of N-propargylcytisine, and its symmetrical dimer linked through 1,3-diyne moiety obtained via a copper-mediated Glaser–Hay oxidative coupling. The products were analyzed by NMR, FT-IR, and mass spectrometry, confirming the introduction of the propargyl moiety and the formation of the diyne bridge. Solvatochromic study of both compounds were performed using UV-VIS absorption spectroscopy in solvents of varying polarity, including protic solvents capable of hydrogen bonding. The 1,3-diyne motif, commonly found in bioactive natural products, endows the resulting dimer with potential for further derivatization and biological evaluation. This study demonstrates the utility of the Glaser–Hay reaction in the functionalization of alkaloid scaffolds and highlights the prospects of N-propargylcytisine derivatives in drug discovery targeting the central nervous system.

Colchicine is a compound isolated from Colchicum autumnale, which is characterized by high anticancer activity. A new amide derivative of colchicine with a squaric acid ester skeleton has been synthesized by the reaction between deacetylated thiocolchicine and diethyl ester of squaric acid. The synthesis under optimized reaction conditions gave the desired product (colchicine monosquarate-amidoester - 5) in the excellent yield of 90 %. This compound crystallizes in the non-centrosymmetric space group P21 of the monoclinic system as dihydrate (5-2H2O) which was confirmed by the X-ray analysis of the single crystal at room temperature. As the temperature decreases to 100 K, the crystal partially loses water that was also confirmed by X-ray single crystal analysis. The obtained amidoester 5 has been analyzed by NMR (1D and 2D), FT-IR and ESI-MS spectroscopy. At room temperature the 1H and 13C NMR spectra showed doubling of signals, which suggested that in the solution, the product existed as rotamers. This hypothesis was confirmed using variable-temperature (VT) 1H NMR and 13C NMR spectroscopies.

Salinomycin (SAL), a natural polyether ionophore, exhibits a broad spectrum of pharmacological activities, including potent anticancer activity. Over the past decade, much effort has been put into developing methods for rational chemical modification of SAL to obtain semisynthetic analogs with higher anticancer activity than the native structure. In this paper, we describe an optimized procedure for synthesizing C20-aminosalinomycin 2 with native stereochemistry at position C20, which was confirmed by single-crystal X-ray diffraction analysis. We further transformed amine precursor 2 into a series of 48 C20-N-(thio)acylated products, including N-(sulfon)amides, N-(thio)ureas, and N-carbamates (urethanes), along with their sulfur analogs, i.e., S-substituted thiocarbamates and dithiocarbamates. This previously unreported class of derivatives showed superior cytotoxicity mostly in the nano- and subnanomolar concentration range and improved selectivity toward human cancer cells compared to those of chemically unmodified SAL and a commonly used oncological drug cisplatin. Of note, the obtained products inhibited the proliferation of reference cancer cells more effectively than their C20-epi-N-acylated counterparts, pointing out the pivotal role of stereochemistry at position C20. Our findings support the premise that the modification of SAL is a fruitful strategy for products with promising biological activity profiles. Moreover, the straightforward protocols should be of significant value for more elaborate modifications of SAL in the future.

Ivermectin (IVR), whose discovery has been Nobel-Prize-honored, is a 16-membered macrocyclic lactone used in medicine as an extremely effective and safe antiparasitic drug. In recent years, interest in this compound has grown due to its potential effectiveness in killing various types of cancer cells. However, research on the anticancer activity of IVR derivatives is limited. Additionally, the growing problem of drug resistance raises concerns about the effectiveness of this drug in the treatment of parasitic diseases. Therefore, in this work, we provide a detailed description of the synthesis of ten new IVR bioconjugates with compounds exhibiting high anticancer and/or antimicrobial activity. We also assess the effectiveness of these hybrids in killing Trypanosoma brucei brucei a protozoan parasite that causes African trypanosomiasis, as well as their anticancer activity toward various cancer cell lines. Many of the newly synthesized conjugates exhibited higher biological activity than their respective parent compounds as well as increased selectivity indices. The IVR conjugate with artesunate (compound 16) appears particularly interesting, as it proved not only to be several times more active than the parent compounds but also showed no toxicity toward a reference cell line, indicating its potential as a therapeutic agent.