Cytostatic Activity Research Articles

РАЗРАБОТКА И ВАЛИДАЦИЯ СПЕКТРОФОТОМЕТРИЧЕСКОЙ МЕТОДИКИ ОПРЕДЕЛЕНИЯ СОДЕРЖАНИЯ ФЛАВОНОИДОВ В ПУПАВКИ КРАСИЛЬНОЙ ТРАВЕ

The aim of this work is development and validation of a spectrophotometric technique for quantification of total flavonoids in terms of rutin in potentially medicinal plant Anthemis tinctoria herb. According to the literature, Anthemis tinctoria is used in folk medicine as a hepatoprotective, hemostatic and means, and its extracts in the experiment exhibit antimicrobial, cytostatic and antioxidant activities. In this work, we used sample of Anthemis tinctoria herb harvested in the summer of 2021 during the period of mass flowering in vicinity of Perm city (valley of the Vasilievka river, Adishchevo railway station). The raw materials were dried at room temperature, with sufficient ventilation, without direct exposure to sunlight, stored separately from other types of raw materials. According to the experiments the optimal conditions for determining of total flavonoids: grinding the raw material to a size passing through a sieve with a diameter of 1 mm, the optimal concentration of ethyl alcohol extractant is 50%, the analytical wavelength is 410 nm, the extraction time in a boiling water bath is 45 minutes, the ratio of extraction and complexing agent - 2% alcohol solution of aluminum chloride - 2:5. The technique was validated in accordance with the requirements of State Pharmacopeia of Russia 14th edition, the relative error of determination with a reliable probability of 95% was 4.00%. The technique can be used in further work to conduct studies of biological activity.

DRUG RESISTANCE: THE STATUS OF THE PROBLEM AND THE SEARCH OF WAYS TO OVERCOME IT (literature review and own research)

The ability of multicellular associates to undergo changes that provide increased resistance to adverse environmental factors determines the development of drug resistance. Over the past decades, it has turned into a complex medical and social problem, which complicates significantly the treatment of countless diseases. In particular, the rapid formation and spread of antibiotic-resistant forms of microorganisms causes the risk of relegating clinical medicine to the pre-antibiotic era. An equally acute problem is the growing resistance of cells of malignant neoplasms to the action of cytostatics as the tumor progresses and during its recurrence. The obvious relevance of these problems for means of counteracting such changes determines the unabated interest in elucidating the molecular and cellular bases of the development of drug resistance. The existence of a certain parallel in the functioning of the cellular societies of biofilms and malignant neoplasms allows us to approach the understanding of the molecular and cellular mechanisms of the development of drug resistance. The role of disruption of the barrier function of the outer cell membranes and the increase in their permeability to extracellular nucleic components is shown in this process. The role of individual components of cellular associates in the formation of drug-resistant, mechanisms of their spread and malignization of surrounding tissues is discussed. Key words: drug resistance, biofilms, malignant neoplasms, cell membranes.

Cloning, expression and anticancer activity of azurin from Pseudomonas aeruginosa VTCC-B-657

Azurin, a small molecular weight protein produced by Pseudomonas aeruginosa and several gram-negative bacteria has received considerable attention because of its potential anti-parasitic, anti-viral and anti-cancer activity. In this study, 437 bp-gene of azurin was amplified and cloned from Pseudomonas aeruginosa VTCC-B-657. This gene was then inserted into the PET22b+ vector and the recombinant plasmid was introduced into Escherichia coli BL21(DE3) by chemical methods. The recombinant strain was checked by polymerase chain reaction method and sequencing analysis. Next, the recombinant azurin (r-Azu) was expressed and purified by Ni2+-ProBondTM resin column. The molecular mass of purified r-Azu was 16 kDa when determined by SDS-PAGE and was 13.88 kDa when determined by LC/MS. Interestingly, the purified r-Azu showed cytostatic activity only on breast cancer cell lines (MCF-7 and MDA with IC50 of 25.4 and 29.25 μg/ml respectively) but not on normal cells. These results suggest that r-Azu would be a potential candidate for anticancer drugs and deserves further study.

Cytostatic Activity of Combretastatin A-4 Derivatives in an In Vitro System.

Cytostatic activity of combretastatin A-4, its 11 analogues, and paclitaxel (Taxacad) was evaluated in vitro on human tumor cells A549 (lung adenocarcinoma) and PC-3 (prostate adenocarcinoma) in order to find the active and stable compound as a promising antitumor agent. 5-(4-Methoxyphenyl)-4-(3,4,5-trimethoxyphenyl)-isoxazole (compound 123124) and 3-(3,4,5-trimethoxyphenyl)-4-(4-methoxyphenyl)-isoxazole (compound 29310186) demonstrated the highest cytostatic activity (IC50≈8×10-9 М). The activity of two other cytotoxic compounds (2E)-1-(7-methoxy-2H-1,3-benzodioxol-5-yl)-3-(4-methoxyphenyl)prop-2-en-1-one (compound 104815) and 4-(3-amino-4-methoxyphenyl)-5-(3,4,5-trimethoxyphenyl)-1H-pyrazole hydrochloride (compound 198732) was close to that of Taxacad: IC50 65×10-9 and 80×10-9 М, respectively, and are also promising active components for the development of antitumor drugs.

Nanomedicines Bearing an Alkylating Cytostatic Drug from the Group of 1,3,5-Triazine Derivatives: Development and Characterization.

Cancer is still one of the major diseases worldwide. The discovery of new drugs and the improvement of existing ones is one of the areas of priority in the fight against cancer. Dioxadet ([5-[[4,6-bis(aziridin-1-yl)-1,3,5-triazin-2-yl]amino]-2,2-dimethyl-1,3-dioxan-5-yl]methanol) represents one of the promising 1,3,5-triazine derivatives and has cytostatic activity towards ovarian cancer. In this study, we first report the development of dioxadet-bearing nanomedicines based on block-copolymers of poly(ethylene glycol) monomethyl ether (mPEG) and poly(D,L-lactic acid) (PLA)/poly(ε-caprolactone) (PCL) and then conduct an investigation into their characteristics and properties. The preparation of narrow-sized nanoparticles with a hydrodynamic diameter of 100-120 nm was optimized using a nanoprecipitation approach. Thoughtful optimization of the preparation of nanomedicines was carried out through adjustments to the polymer's molecular weight, the pH of the aqueous medium used for nanoprecipitation, the initial drug amount in respect to the polymer, and polymer concentration in the organic phase. Under optimized conditions, spherical-shaped nanomedicines with a hydrodynamic diameter of up to 230 nm (PDI < 0.2) containing up to 592 ± 22 μg of dioxadet per mg of polymer nanoparticles were prepared. Study of the drug's release in a model medium revealed the release up to 64% and 46% of the drug after 8 days for mPEG-b-PLA and mPEG-b-PCL, respectively. Deep analysis of the release mechanisms was carried out with the use of a number of mathematical models. The developed nanoparticles were non-toxic towards both normal (CHO-K1) and cancer (A2780 and SK-OV-3) ovarian cells. A cell cycle study revealed lesser toxicity of nanomedicines towards normal cells and increased toxicity towards cancer cells. The IC50 values determined for dioxadet nanoformulations were in the range of 0.47-4.98 μg/mL for cancer cells, which is close to the free drug's efficacy (2.60-4.14 μg/mL). The highest cytotoxic effect was found for dioxadet loaded to mPEG-b-PCL nanoparticles.

Поражение органа зрения при болезни Вегенера. Клинический случай

The article provides a description of clinical case of patient 53 years old with Wegener's granulomatosis, manifested with necrotizing scleritis of the left eyeball against the background of malignant nose granuloma. The patient underwent sclera plastic surgery twice in order to save the eye. Due to intensive corticosteroid and cytostatic therapy clinical activity of vasculitis was reduced. At the same time was observed further growth of nose granoluma with damage of inferior orbital wall and spread of the tumor to the orbital cavity with the subsequent destruction of the eye. It was performed an enucleation of the left eye with removal of the tumor of the left orbit. The Wegener's granulomatosis diagnosis was confirmed histologically. The problem of treating systemic vasculitis and its complications is very relevant. During 5-year observation period the patient there were noted another complications: septal perforation, oroantral fistula formation, formation of bilateral hearing loss, disintegration of the left lung granuloma. Right eye stayed intact during whole observation period. Prognosis is unfavorable not only for eyesight, but also for patient's life. Keywords: Wegener's disease, granulomatosis with polyangiitis, necrotizing sleritis

Long-Term Fenofibrate Treatment Stimulates the Phenotypic Microevolution of Prostate Cancer Cells In Vitro.

Fenofibrate is a widely used anti-hyperlipidemic agonist of peroxisome proliferator-activated receptor alpha (PPARα). As a metabolic blocker, fenofibrate interferes with cancer promotion/progression via its misbalancing effects on cellular metabolism. However, the consequences of its long-term application for patients with diagnosed drug-resistant cancers are unknown. We addressed this point by tracing the phenotypic microevolution of naïve and drug-resistant prostate cancer PC3_DCX20 cells that underwent a long-term exposition to 10 μM and 50 μM fenofibrate. Their resistance to fenofibrate, metabolic profile and invasive phenotype were estimated in the control conditions and under fenofibrate-induced stress. Apparently, drug efflux systems are not effective against the cytostatic FF action. However, wtPC3 and PC3_DCX20 cells that survived the long-term 50 μM fenofibrate treatment gave rise to lineages that displayed an increased proliferation rate, lower motility in the control conditions and enhanced fenofibrate resistance. Attenuated fenofibrate bioavailability modified the pattern of PC3 microevolution, as illustrated by phenotypic differences between wtPC3/PC3_DCX20 lineages propagated in the presence of 50 μM and 10 μM fenofibrate. Collectively, our observations indicate that fenofibrate acts as a selective factor that affects prostate cancer microevolution. We also pinpoint potential consequences of long-term exposition of prostate cancer patients to metabolic blockers.

Synthesis and Antitumor Activity of a GSH Inert Bisphosphonate Platinum (II) Complex

Osteosarcoma is a highly aggressive neoplasm. Traditional platinum chemotherapeutic agents for osteosarcoma inevitably have acquired drug resistance and serious side effects, which have limited their utility. To slow down the reaction of platinum drugs with glutathione (GSH) is a strategy to overcome the resistance of platinum chemotherapeutic agents. Herein, the unique design of a GSH inert bisphosphonate platinum complex cis-{di(amino)platinum[tetraethyl 2,2-bis(2-pyridinylmethyl)methylidene-1,1-bisphosphonate]} (DBPP) is reported. MTT assay demonstrates that DBPP showed moderate inhibition towards human osteosarcoma cell line U2OS cells. The cytostatic action of DBPP is related to conformational conversion from B-DNA to A-DNA and the unwinding of pUC19 DNA. DBPP could also destroy the tertiary structure of human serum albumin (HSA). Notably, 31P NMR and 1H NMR indicate that DBPP can hardly chelate with GSH, which could overcome the GSH-induced side effects. We envision that this unique design of the platinum complex would open up new ways to overcome GSH-induced resistance.

The Cytostatic Action of Dinitrosyl Iron Complexes with Glutathione on Escherichia coli Cells Is Mediated by Nitrosonium Cations Released from These Complexes.

This study demonstrates a bacteriostatic effect of binuclear dinitrosyl iron complexes with glutathione on Escherichia coli TN300 cells. It has been quantified by the colony formation assay. The bacteriostatic effect exerted by these complexes increases considerably in the presence of diethyldithiocarbamate. Our results suggest that this effect is caused by the intense release of nitrosonium cations, NO+, from the complexes, which decompose under the action of diethyldithiocarbamate. A similar effect is observed when E.coli cells are treated with diethyldithiocarbamate 40 min after the addition of sodium nitrite or S-nitrosoglutathione. Notably, the level of dinitrosyl iron complexes observed in the bacterial cells due to the effects of sodium nitrite or S-nitrosoglutathione is almost the same as that obtained after treatment with glutathione-containing complexes. The bacteriostatic effects of the NO molecules released from nitrite or S-nitrosoglutathione during their brief interaction with bacteria were significantly smaller than the bacteriostatic effect of NO+. Wededuce therefrom that the nitrosonium cations released from DNICs are responsible for the observed bacteriostatic effect of these complexes in E. coli cells.

Highly Branched Betulin Based Polyanhydrides for Self-Assembled Micellar Nanoparticles Formulation.

Polyanhydrides based on betulin are promising materials for use in controlled drug delivery systems. Due to the broad biological activity of betulin derivatives and lack of toxicity in vitro and in vivo, these polymers can be used both as polymeric prodrug and as carriers of other biologically active compounds. In this study, we develop a novel amphiphilic branched polyanhydrides synthesized by the two-step melt polycondensation of betulin disuccinate (DBB) and a tricarboxylic derivative of poly(ethylene glycol) (PEG_COOH). DBB and PEG_COOH were used as the hydrophobic and hydrophilic segments, respectively. The content of DBB in copolymers was from 10 to 95 wt%. Copolymers were assessed for their cytostatic activity against various cancer cell lines. Compared to linear DBB and PEG-based polyanhydrides, the branched polyanhydrides exhibited higher anticancer activity. The obtained polymers were able to self-assemble in water to form micelles with hydrodynamic diameters from 144.8 to 561.8 nm. and are stable over a concentration range from 12.5 µg/mL to 6.8 mg/mL. The formed micelles were found to be spherical in shape using a scanning electron microscope. It was found that the structure and composition of polyanhydrides affected the hydrodynamic diameter of the micelles. The branched betulin-based polyanhydrides have the potential to serve as biodegradable polymer prodrugs or carriers for other bioactive compounds.

Design and synthesis of novel quinazolinone-based derivatives as EGFR inhibitors with antitumor activity

Nineteen new quinazolin-4(3H)-one derivatives 3a–g and 6a–l were designed and synthesised to inhibit EGFR. The antiproliferative activity of the synthesised compounds was tested in vitro against 60 different human cell lines. The most potent compound 6d displayed superior sub-micromolar antiproliferative activity towards NSC lung cancer cell line NCI-H460 with GI50 = 0.789 µM. It also showed potent cytostatic activity against 40 different cancer cell lines (TGI range: 2.59–9.55 µM). Compound 6d potently inhibited EGFR with IC50 = 0.069 ± 0.004 µM in comparison to erlotinib with IC50 value of 0.045 ± 0.003 µM. Compound 6d showed 16.74-fold increase in total apoptosis and caused cell cycle arrest at G1/S phase in breast cancer HS 578T cell line. Moreover, the most potent derivatives were docked into the EGFR active site to determine their binding mode and confirm their ability to satisfy the pharmacophoric features required for EGFR inhibition.

Lapatinib- and fulvestrant-PAMAM dendrimer conjugates promote apoptosis in chemotherapy-induced senescent breast cancer cells with different receptor status.

Lapatinib (L) and fulvestrant (F) are used in targeted anticancer therapies, in particular, against phenotypically different breast cancer cells. L, a dual inhibitor of EGFR and HER2 tyrosine kinases, is active against HER2-positive breast cancer cells, while F, a selective estrogen receptor degrader (SERD), is active against ER-positive breast cancer cells. However, the action of L and F can be limited due to their relatively low water solubility and bioavailability. In the present study, poly(amidoamine) (PAMAM) dendrimer G3 was functionalized with L or F or L and F to compare their effects with free L or F against breast cancer cells with different receptor status (ER-positive MCF-7, triple negative MDA-MB-231 and HER2-positive SK-BR-3 cells). L-PAMAM and F-PAMAM conjugates potentiated cytostatic and cytotoxic action of L and F that was accompanied by elevated levels of autophagy. TRDMT1, RNA methyltransferase, was also involved in this response as judged by TRDMT1 nuclear translocation and nano-drug resistance of TRDMT1 gene knockout cells. Nano-drugs also promoted elimination of doxorubicin-induced senescent breast cancer cells by apoptosis-mediated senolysis regardless of receptor status. In conclusion, we propose a novel anticancer approach based on L-PAMAM and F-PAMAM nanoplatforms being effective, at least, against breast cancer cells with different phenotypic features.

In vitro and in vivo local tolerability of a synergistic anti-tuberculosis drug combination intended for pulmonary delivery.

A drug combination, vancomycin (VAN) plus tetrahydrolipstatin (THL), has demonstrated an effective synergistic action in vitro against Mycobacterium tuberculosis (Mtb). The poor oral bioavailability of VAN and THL and the predominant tropism of Mtb infection to the lungs make their pulmonary administration very attractive. To evaluate their local tolerability, bronchial cells, alveolar cells and monocytes were exposed to concentrations around and above their minimal inhibitory concentration (MIC). The VAN had no inhibitory activity on the tested human cell lines, even at a concentration 125 times higher than its MIC, whereas the THL, alone or in combination with VAN, presented a cytostatic action. Monolayer epithelium showed no significant irreversible damage at concentrations up to 100 times the combination MIC. BALB/cAnNRj mice exposed to concentration of 50 times the combination MIC delivered endotracheally 3 times a week for 3 weeks showed no clinical signs or significant weight loss. The increase of proinflammatory biomarkers (i.e., IL-1, IL-6, TNF-α and proportion of inflammatory cells) and cytotoxicity in bronchoalveolar lavage fluid (BALF) were non-significant. Lung histopathology did not show significant tissue damage. The VAN/THL combination at doses up to 50 times the combination MIC is found to be thus well tolerated by pulmonary route. This study is a promising result and encouraging further investigations of pulmonary administration of VAN/THL combination as dry powder for anti-tuberculosis treatment.

DNA Framework-Programmed Ligand Positioning to Modulate the Targeting Performance.

Effective targeting of nanomedicine is still an intricacy since unsatisfactory clinical trial feedback demonstrated their inadequate concentration at the desired area. However, the regulatory effect of ligand-modification patterns on the targeting effect has not been surveyed yet. Based on the superior spatial addressability of DNA frame structures, herein DNA tetrahedrons were used as templates for site-specific modification of targeting ligands. In this work, nanovectors with homogeneous ligand-modification patterns, including various valence of ligands and the precisely controlled distance between ligands at the nanoscale, were established for the first time. In vitro and in vivo targeting performance studies found that merely relying on the augment of the ligand quantity exhibited a confined promotion effect on the targeting efficiency. Notably, the space distance between ligands displayed a more important role in reforming the targeting effect, and the largest ligand distance (approximately 156.55 Å) pattern exhibited an optimal targeting effect and prominently cytostatic activity toward tumor cells. Generally, the survey of ligand-modification patterns on nanovectors provided a valid guidance to direct the optimization of nanomedicine.

Development of camptothecin nano-prodrugs based on trimethyl lock groups toward selective drug release in cancer cells

Selective drug release at the tumor site contributes to the reduction of side effects caused by anticancer treatments. To achieve a selective drug release system in cancer cells, we designed a new prodrug in which the anticancer drug camptothecin (CPT) is linked to a trimethyl lock (TML) group by an ester bond. Evaluation of in vitro cytostatic activity and drug release kinetics of the CPT-TML nano-prodrugs revealed that the ester of CPT-TML was stable against hydrolysis due to the steric hindrance around the ester derived from the tertiary hydroxy group. In contrast, CPT was smoothly released via sterically hindered ester cleavage by lactonization of the activated TML group. This finding will help in the development of nano-prodrugs with high selectivity at tumor site.

Caffeic Acid Phenethyl Ester as a DHODH Inhibitor and Its Synergistic Anticancer Properties in Combination with 5-Fluorouracil in a Breast Cancer Cell Line.

IntroductionA combination of chemotherapy agents is the best choice in breast cancer treatment to increase the patient survival rate. 5-fluorouracil (5-FU) is one of the drugs applied in combination with other drugs to control and delay development of cancer cells. Nevertheless, the occurrence of multidrug resistance and dose-limiting cytotoxicity have limited the efficacy of 5-FU treatment. Therefore, the discovery of new anti-breast cancer drugs should be pursued.ObjectiveTo study potency of a promising naturally derived compound, caffeic acid phenethyl ester (CAPE), for breast cancer treatment in single and combination with 5-FU.MethodsCytotoxicity of CAPE, 5-FU, and 5-FU+CAPE was studied by in vitro MTT experiment in MCF-7 cell line, and RT-PCR analysis was used to evaluate the change in gene expression due to the treatment. Moreover, an enzymatic assay and molecular docking analysis were applied to evaluate the possible mechanism of substance-induced apoptosis.ResultsThe study revealed that a single treatment of CAPE showed cytotoxicity with IC50 6.6 ± 1.0 µM and 6.5 ± 2.9 µM at 24 h and 48 h, respectively. Meanwhile, 5-FU showed cytostatic activity. The 5-FU + CAPE has a synergistic effect at 24 h treatment with a CI = 0.5 and an additive effect at 48 h treatment with CI = 1.0. CAPE was also found to enhances the mRNA expression of caspase-8 and BAX within 6 hours in combination with 5-FU compared to 5-FU treatment alone. Our study reveals a new mechanism of CAPE which is related to the inhibition of human dihydroorotate dehydrogenase (HsDHODH) with an IC50 of 120.7 ± 6.8 µM, by bound to the ubiquinone-binding site of the enzyme and could be responsible for inducing extrinsic and intrinsic apoptosis.ConclusionThis study demonstrated the cytotoxicity of CAPE potential to induce apoptosis of breast cancer MCF-7 cell line single and cytotoxic–cytostatic combination with 5-FU. Therefore, further studies to develop CAPE and its derivatives will be required to discover new candidates for breast cancer agents.

Cytostatic effects of structurally different ginsenosides on yeast cells with altered sterol biosynthesis and transport

Triterpene glycosides are a diverse group of plant secondary metabolites, consisting of a sterol-like aglycon and one or several sugar groups. A number of triterpene glycosides show membranolytic activity, and, therefore, are considered to be promising antimicrobial drugs. However, the interrelation between their structure, biological activities, and target membrane lipid composition remains elusive. Here we studied the antifungal effects of four Panax triterpene glycosides (ginsenosides) with sugar moieties at the C-3 (ginsenosides Rg3, Rh2), C-20 (compound K), and both (ginsenoside F2) positions in Saccharomyces cerevisiae mutants with altered sterol plasma membrane composition. We observed reduced cytostatic activity of the Rg3 and compound K in the UPC2-1 strain with high membrane sterol content. Moreover, LAM gene deletion reduced yeast resistance to Rg3 and digitonin, another saponin with glycosylated aglycon in the C-3 position. LAM genes encode plasma membrane-anchored StARkin superfamily-member sterol transporters. We also showed that the deletion of the ERG6 gene that inhibits ergosterol biosynthesis at the stage of zymosterol increased the cytostatic effects of Rg3 and Rh2, but not the other two tested ginsenosides. At the same time, in silico simulation revealed that the substitution of ergosterol with zymosterol in the membrane changes the spatial orientation of Rg3 and Rh2 in the membranes. These results imply that the plasma membrane sterol composition defines its interaction with triterpene glycoside depending on their glycoside group position. Our results also suggest that the biological role of membrane-anchored StARkin family protein is to protect eukaryotic cells from triterpenes glycosylated at the C-3 position.

Anti-fungal activity of anthraquinone derivatives (Part 1)

The problems of treatment and prevention of infectious diseases, due to the diversity of biological forms of pathogens, the constant emergence of multi-resistant forms, the emergence of new types of dangerous pathogens, determine the relevance of the problem of creating new antimicrobial agents. Over the past few decades, there has been an increase in the incidence of fungal infections worldwide, as well as an increase in the resistance of some types of fungi to various antifungal drugs used in medical practice. The purpose of the review is to provide information on the current state of fungal diseases and the search for new antifungal structures among natural compounds, in particular anthraquinone derivatives. Objects. Derivatives of 9,10-anthraquinone: chrysophanol, emodin, physсion, rhein, aloe-emodin). Results. Currently, special attention has been paid to natural sources of antimicrobial agents, which can be considered as an alternative to traditionally used drugs. Nature is a valuable source of new compounds and a rich arsenal of biologically active metabolites for the search for new drugs. Chemistry of anthraquinone derivatives is an independent and extensive field of organic and bioorganic chemistry with a wide range of practical applications. Quite a large number of compounds of the anthraquinone series have been found in plants, animals, and microorganisms. Many natural and synthetic derivatives of anthraquinones exhibit a variety of pharmacological activities, among which compounds with antitumor, cytostatic, anti-inflammatory, hormonal, antiviral, and other activities have been identified. The review analyzes the antifungal effects of various types of natural anthraquinone molecules (chrysophanol, emodin, physсion, rhein, aloe-emodin), as well as some structurally related derivatives, to assess the effect of structural parameters of molecules on their activity. Conclusion. Natural objects contain a variety of biologically active derivatives of 9,10-anthraquinone. They can be considered as promising structures for the search for new antifungal agents.

Abstract 1545: The cytostatic effect of miR-3189-3p in triple negative breast cancer cells involves inhibition of mitochondrial-mediated apoptosis

Abstract Our laboratory has previously characterized a microRNA, miR-3189-3p, with potent anti-cancer activity against glioblastoma and triple negative breast cancer (TNBC), two of the most aggressive types of tumors. Intriguingly, while miR-3189-3p inhibits proliferation, migration, and invasion of glioblastoma and TNBC cells, it does not induce apoptosis. The BCL2 family of proteins controls mitochondrial-mediated cell death through binding affinity and abundance of pro- and anti-apoptotic factors. Here, we investigated the mechanisms of the cytostatic effect of miR-3189-3p on MDA-MB-231 cells and found that the BCL2-family members and pro-apoptotic factors BAK1, BMF, and HRK, which are predicted gene target of this miRNA, are indeed downregulated by the miRNA mimic. In addition, we found that expression of miR-3189-3p improved the metabolic fitness of TNBC cells through increasing both mitochondrial respiration and glycolysis. Ongoing experiments are aimed at understanding how changes in the metabolic profile and cytostatic activity of miR-3189-3p could be used for therapeutic intervention against this aggressive tumor. Citation Format: Cecilia Vittori, Hassan Yousefi, Krzysztof Reiss, Francesca Peruzzi. The cytostatic effect of miR-3189-3p in triple negative breast cancer cells involves inhibition of mitochondrial-mediated apoptosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1545.

Abstract 5313: A BCL-XL PROTAC degrader DT2216 synergizes with KRASG12C inhibitors for effectively treating KRASG12C-mutated cancers

Abstract Purpose: Mutations in KRAS are the most common oncogenic drivers. Sotorasib (AMG510), a covalent inhibitor selectively targeting KRASG12C, was recently approved for the treatment of KRASG12C-mutated non-small cell lung cancer (NSCLC). However, the clinical efficacy of sotorasib and other KRASG12C inhibitors is limited by intrinsic resistance in colorectal cancer (CRC) and by the rapid emergence of acquired resistance in all treated solid tumors. Therefore, there is an urgent need to develop novel combination therapies to overcome sotorasib resistance and to maximize its efficacy. Experimental Design: A panel of KRASG12C-mutated cell lines from NSCLC, CRC and pancreatic cancer (PC) were treated with sotorasib alone or in combination with BCL-XL proteolysis targeting chimera (PROTAC, such as DT2216) to assess effects on cell viability, colony formation and apoptosis. To identify mechanisms underlying sotorasib+DT2216 combination responses, we analyzed KRAS downstream signaling and expression of BCL-2 family proteins, and performed co-immunoprecipitation of BCL-XL to evaluate its interaction with pro-apoptotic BH3-only proteins. Finally, therapeutic efficacy of sotorasib alone and in combination with DT2216 was evaluated in vivo using different tumor xenograft models. Results: We observed heterogeneous responses to sotorasib alone, whereas its combination with DT2216 strongly inhibited viability of KRASG12C cell lines that partially responded to sotorasib treatment. Mechanistically, co-treatment with DT2216 inhibited sotorasib-induced BCL-XL/BIM interaction leading to enhanced apoptosis. Furthermore, DT2216 co-treatment significantly improved the antitumor efficacy of sotorasib in vivo. Conclusions: Our findings suggest that due to cytostatic activity, the efficacy of sotorasib is limited, and therefore its combination with a pro-apoptotic agent DT2216 shows synergistic responses and can potentially overcome resistance. Citation Format: Sajid Khan, Janet Wiegand, Peiyi Zhang, Wanyi Hu, Dinesh Thummuri, Vivekananda Budamagunta, Nan Hua, Lingtao Jin, Carmen J. Allegra, Edmund S. Kopetz, Maria Zajac-Kaye, Frederic J. Kaye, Guangrong Zheng, Daohong Zhou. A BCL-XL PROTAC degrader DT2216 synergizes with KRASG12C inhibitors for effectively treating KRASG12C-mutated cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5313.