Synergistic Effect Of Combination Research Articles

Abstract 1938: WEE1 inhibition prevents and overcomes resistance to KRAS inhibitors in lung cancer by enhancing MCL1-mediated apoptosis

Abstract Background: While novel covalent inhibitors of KRAS G12C have been approved in non-small-cell lung cancer (NSCLC), their efficacies are known to be limited. To enhance the therapeutic potential of KRAS inhibitors, combination strategies need to be developed. In this study, we conducted a large-scale screening to identify novel combination partners that induced synergistic efficacy with KRAS inhibitors. Additionally, mechanistic analyses were conducted to clarify the synergistic effects in combination and their role in conferring resistance to KRAS inhibitors. Methods: To identify novel combination partners of KRAS inhibitors, we conducted high-throughput screening (HTS) using a chemical library composed of 1,400 kinase inhibitors. Sotorasib was used as a KRAS inhibitor. Anti-proliferative and apoptotic effects in vitro were assessed by ATP-based cell viability assay, and caspase 3/7 assay and/or Annexin V assay, respectively. Protein expression levels were assessed by immunoblotting. In vivo studies were performed using a H358 xenograft nude mouse model and a patient-derived xenograft model (PDX). PDX samples were provided by the National Cancer Center J-PDX library, Japan. Results: HTS identified the WEE1 inhibitor AZD1775, a G2/M checkpoint abrogator in clinical-stage development, as a promising combination partner of KRAS inhibitors in KRAS G12C mutant NSCLC. Synergistic effects of KRAS and WEE1 inhibitors were confirmed across multiple KRAS G12C mutant NSCLC cell lines, independently of their co-occurring oncogenic mutation profiles. The combination treatment enhanced apoptotic cell death, being upregulated pro-apoptotic protein BIM, while downregulated anti-apoptotic protein MCL1. In vivo efficacy studies in combination with sotorasib and AZD1775 also demonstrated remarkable tumor regression and durable response in both CDX and PDX models. We also generated sotorasib-resistant H23 (H23-SR) cells, confirming upregulation of both WEE1 and MCL1 in the resistant cells. Ectopic overexpression of WEE1 in H23, on the contrary, conferred resistance to sotorasib. Furthermore, WEE1 inhibition re-sensitized H23-SR cells to KRAS inhibitors. Conclusion: Our results suggest that the WEE1-MCL1 axis plays an important role in both the initial therapeutic efficacy and the acquired resistance to KRAS inhibitors. These findings could pave the way for a novel therapeutic strategy for KRAS G12C mutant NSCLC. Citation Format: Gaku Yamamoto, Kosuke Tanaka, Ryo Kamata, Takehiro Nakao, Shunta Mori, Jie Liu, Susumu S. Kobayashi, Akihiro Ohashi. WEE1 inhibition prevents and overcomes resistance to KRAS inhibitors in lung cancer by enhancing MCL1-mediated apoptosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1938.

Abstract 944: Pre-clinical activity of the Wnt pathway inhibitor RXC004 in combination with MAPK pathway inhibitors in GI cancer models

Abstract Background: Gastrointestinal (GI) cancers cause more cancer deaths than any other body system, with 3.4 million related deaths in 2018. Wnt pathway activation is common in GI cancers, with the pathogenic upstream Wnt pathway variant sub-population (RNF43 loss of function/RSPO gain of function) showing a combined prevalence of 4.7% in GI cancer patients; pre-clinically this sub-population shows exquisite sensitivity to RXC004, a small molecule Porcupine inhibitor. A striking co-occurrence of upstream Wnt pathway variants with MAPK pathway driver mutations (KRAS, BRAF, NRAS) was detected in 77% of Microsatellite stable (MSS) GI cancers, suggesting co-inhibiting these pathways could enhance clinical activity in these patients. Methods: In vitro proliferation assays were performed in pre-clinical models of upstream Wnt pathway mutated MSS GI cancer (SNU-1411, HPAF-II and AsPC-1) using Wnt (RXC004) or MAPK (Trametinib) pathway inhibitors at multiple concentrations as single agents or in combination. Control cells with downstream Wnt pathway mutations (WiDr and HCT116) were also tested. Synergistic combination effects were detected by BLISS scores. RXC004 (1.5mg/kg QD) and Trametinib (0.3mg/kg QD) were evaluated in an RSPO-fusion xenograft model (SNU-1411) as single agents or in combination. Efficacy was measured by tumour volume and weight; PD markers were assessed in end of study tumour samples. Relative AXIN2 and DUSP6 gene expression changes were determined upon inhibitor treatment by quantitative Polymerase Chain Reaction (qPCR). Results: RXC004 in combination with Trametinib demonstrated strong anti-proliferative synergy in SNU-1411 cells and moderate synergy/additivity in HPAF-II and AsPC-1 cells; no synergy was observed in control cells. In vivo, RXC004 and Trametinib monotherapy led to significant moderate tumour growth control (p<0.05) at the doses tested, whereas their combination led to significantly enhanced efficacy (p<0.05). Gene expression analysis demonstrated a reciprocal Wnt/MAPK signaling mechanism; RXC004 strongly suppressed Wnt signaling (AXIN2) but increased MAPK signaling (DUSP6), whilst Trametinib strongly suppressed MAPK signaling (DUSP6) but increased Wnt signaling (AXIN2). Combination of RXC004 and Trametinib sustained inhibition of both Wnt and MAPK signalling. Similar effects were observed with inhibitors of other MAPK pathway components. Conclusion: Wnt and MAPK pathways are frequently co-activated in GI cancers, particularly in the upstream Wnt pathway mutated sub-population. Pre-clinically we show that Wnt and MAPK pathways act as potential reciprocal resistance mechanisms following single agent inhibition of either pathway; co-inhibition of these pathways leads to synergistic effects in vitro and enhanced efficacy in vivo. This provides a clear rationale to assess this combination approach in the clinic. Citation Format: Simon A. Woodcock, Dorottya Keppel, Catherine Eagle, James Kelly, Eimear Flanagan, Emma Bishop, Inder Bhamra, Clifford D. Jones, Richard Armer, Jane Robertson, Caroline Phillips. Pre-clinical activity of the Wnt pathway inhibitor RXC004 in combination with MAPK pathway inhibitors in GI cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 944.

Abstract 7125: Inhibition of IDH1 impairs homologous recombination and induces sensitivity to PARP inhibitor in pancreatic cancer

Abstract Introduction: Pancreatic ductal adenocarcinoma (PDAC) is a major cause of cancer-related deaths in the United States. While Poly (ADP-ribose) polymerase (PARP) inhibitors hold promise in treating PDAC with Homologous Recombination Deficiency (HRD). However, HRD occurs in only 10% of cases, leaving 90% with intact Homologous Recombination Proficiency (HRP). Our research highlights the key role of wild-type isocitrate dehydrogenase 1 (IDH1) in maintaining cellular function. We found that inhibiting IDH1 increases DNA damage, suppressing the DNA repair pathway crucial for genomic integrity. This makes cancer cells susceptible to PARP inhibitors, offering a new PDAC treatment approach. Methods: The effect of IDH1 inhibition (Ivosidenib) combined with PARP inhibition (Olaparib) on in vitro growth inhibition were assessed through Trypan blue and PicoGreen in drug combination assays. Additionally, we investigated the molecular mechanism underlying the synergistic effects of drug combination. To further evaluate the therapeutic potential of IDH1 inhibition in combination with PARP inhibitors, we examined tumor growth in xenograft models of PDAC in athymic nude mice. Results: Our data report that, mechanistically, IDH1 inhibition decreased expression of HR DNA repair pathway molecules, such as BRCA1 and BRCA2, and leading to decreased HR repair efficiency in pancreatic cancer cells. Short-term cell viability data demonstrated that targeting IDH1 with ivosidenib when combined with DNA-damaging agent (Olaparib) had a synergistic effect in HRP cell lines (MiaPaCa-2 and Panc-1) with a positive synergy score and Bliss score greater than 1. Additionally, we assessed long-term cell survival using colony formation assays, which yielded a dramatic reduction in cell survival for both Panc1 and MiaPaCa-2 cells when olaparib was combined with ivosidenib, as compared to single-agent controls. Consequently, this reduction increased the levels of apoptosis induced by olaparib. Furthermore, we discovered that these two compounds complemented each other in DNA damage response, leading to an increase in the DNA damage biomarker γ-H2AX. In vivo studies using xenograft models demonstrated that the combination of ivosidenib and olaparib synergistically enhanced anti-tumor activity as compared to either single-agent used alone. Conclusion: Our data provides insights into the mechanisms underlying the susceptibility of PDAC tumor growth to a dual treatment approach involving an IDH1 inhibitor and a PARP inhibitor, particularly in the context of HRP cancer. This highlights the promise of precision medicine for pancreatic cancer treatment, though further pre-clinical studies are needed for validation and refinement. Citation Format: Mehrdad Zarei, Omid Hajihassani, Hallie J. Graor, Alexander W. Loftus, Soubhi Tahhan, Faith Nakazzi, Parnian Naji, Luke D. Rothermel, Jonothan R. Brody, Jordan M. Winter. Inhibition of IDH1 impairs homologous recombination and induces sensitivity to PARP inhibitor in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7125.

Antioxidant capacity of an ethanolic extract of Elaeagnus x submacrophylla Servett. leaves

In this study, we investigated the ethanolic extraction of the leaves of a very common but little studied plant species, Elaeagnus x submacrophylla Servett. and the opportunity of generating an antioxidant ingredient. The phytochemical profile of an ethanolic extract is also described here using gas chromatography and ultra-performance liquid chromatography, both combined with mass spectrometry (GC-MS and UPLC-MS), highlighting the presence of flavonoids, saponins, triterpenoids and a set of volatile compounds. Through in vitro assays (DPPH, ABTS, ORAC), the free radical scavenging capacity of the ingredient was then investigated (from 0.25 to 1.75 mmol TE/g) and compared with well-known standard antioxidants (BHT, gallic acid, quercetin, Trolox and vitamin C). In addition, in cellulo antioxidant capacity was performed using mice fibroblasts, revealing an activity equivalent to 50 mg/L of quercetin when tested the ethanolic extract in the concentration range of 50–300 mg/L, suggesting a synergistic combination effect of the identified phytochemicals. These results support the use of Elaeagnus x submacrophylla as a source of antioxidant ingredients.

Facile synthesis of Fe2O3, Fe2O3@CuO and WO3 nanoparticles: characterization, structure determination and evaluation of their biological activity

Due to their high specific surface area and its characteristic’s functionalized nanomaterials have great potential in medical applications specialty, as an anticancer. Herein, functional nanoparticles (NPs) based on iron oxide Fe2O3, iron oxide modified with copper oxide Fe2O3@CuO, and tungsten oxide WO3 were facile synthesized for biomedical applications. The obtained nanomaterials have nanocrystal sizes of 35.5 nm for Fe2O3, 7 nm for Fe2O3@CuO, and 25.5 nm for WO3. In addition to octahedral and square nanoplates for Fe2O3, and WO3; respectively. Results revealed that Fe2O3, Fe2O3@CuO, and WO3 NPs showed remarked anticancer effects versus a safe effect on normal cells through cytotoxicity test using MTT-assay. Notably, synthesized NPs e.g. our result demonstrated that Fe2O3@CuO exhibited the lowest IC50 value on the MCF-7 cancer cell line at about 8.876 µg/ml, compared to Fe2O3 was 12.87 µg/ml and WO3 was 9.211 µg/ml which indicate that the modification NPs Fe2O3@CuO gave the highest antiproliferative effect against breast cancer. However, these NPs showed a safe mode toward the Vero normal cell line, where IC50 were monitored as 40.24 µg/ml for Fe2O3, 21.13 µg/ml for Fe2O3@CuO, and 25.41 µg/ml for WO3 NPs. For further evidence. The antiviral activity using virucidal and viral adsorption mechanisms gave practiced effect by viral adsorption mechanism and prevented the virus from replicating inside the cells. Fe2O3@CuO and WO3 NPs showed a complete reduction in the viral load synergistic effect of combinations between the tested two materials copper oxide instead of iron oxide alone. Interestingly, the antimicrobial efficiency of Fe2O3@CuO NPs, Fe2O3NPs, and WO3NPs was evaluated using E. coli, S. aureus, and C. albicans pathogens. The widest microbial inhibition zone (ca. 38.45 mm) was observed with 250 mg/ml of WO3 NPs against E. coli, whereas using 40 mg/ml of Fe2O3@CuO NPS could form microbial inhibition zone ca. 32.86 mm against S. aureus. Nevertheless, C. albicans was relatively resistant to all examined NPs. The superior biomedical activities of these nanostructures might be due to their unique features and accepted evaluations.

Assessing silver nanoparticle and antimicrobial combinations for antibacterial activity and biofilm prevention on surgical sutures.

To evaluate the effect of silver nanoparticles alone and in combination with Triclosan, and trans-cinnamaldehyde against Staphylococcus aureus and Escherichia coli biofilms on sutures to improve patients' outcomes. Silver nanoparticles were prepared by chemical method and characterized by UV-visible spectrophotometer and dynamic light scattering. The minimum inhibitory concentration was assessed by the Microdilution assay. The antibiofilm activity was determined using crystal violet assay. A checkerboard assay using the fractional inhibitory concentration index and time-kill curve was used to investigate the synergistic effect of silver nanoparticle combinations. The hemolytic activity was determined using an erythrocyte hemolytic assay. Our results revealed that silver nanoparticles, Triclosan, and trans-cinnamaldehyde (TCA) inhibited S.aureus and E.coli biofilms. Silver nanoparticles with TCA showed a synergistic effect (FICI values 0.35 and 0.45 against S. aureus and E. coli biofilms, respectively), and silver nanoparticles with Triclosan showed complete inhibition of S. aureus biofilm. The hemolytic activity was<2.50% for the combinations.

Interpreting drug synergy in breast cancer with deep learning using target-protein inhibition profiles

BackgroundBreast cancer is the most common malignancy among women worldwide. Despite advances in treating breast cancer over the past decades, drug resistance and adverse effects remain challenging. Recent therapeutic progress has shifted toward using drug combinations for better treatment efficiency. However, with a growing number of potential small-molecule cancer inhibitors, in silico strategies to predict pharmacological synergy before experimental trials are required to compensate for time and cost restrictions. Many deep learning models have been previously proposed to predict the synergistic effects of drug combinations with high performance. However, these models heavily relied on a large number of drug chemical structural fingerprints as their main features, which made model interpretation a challenge.ResultsThis study developed a deep neural network model that predicts synergy between small-molecule pairs based on their inhibitory activities against 13 selected key proteins. The synergy prediction model achieved a Pearson correlation coefficient between model predictions and experimental data of 0.63 across five breast cancer cell lines. BT-549 and MCF-7 achieved the highest correlation of 0.67 when considering individual cell lines. Despite achieving a moderate correlation compared to previous deep learning models, our model offers a distinctive advantage in terms of interpretability. Using the inhibitory activities against key protein targets as the main features allowed a straightforward interpretation of the model since the individual features had direct biological meaning. By tracing the synergistic interactions of compounds through their target proteins, we gained insights into the patterns our model recognized as indicative of synergistic effects.ConclusionsThe framework employed in the present study lays the groundwork for future advancements, especially in model interpretation. By combining deep learning techniques and target-specific models, this study shed light on potential patterns of target-protein inhibition profiles that could be exploited in breast cancer treatment.

The role of immunotherapy sensitizers and novel immunotherapy modalities in the treatment of cancer.

The importance of the immune system in the response against cancer has always been a subject of intense investigation. The advent of immune checkpoint inhibitors has transformed the landscape of oncologic treatments, while expanding the understanding of this disease's pathophysiology. Consequently, many therapies are being investigated, with interventions directed at different steps and pathways of the immune response. Relevantly, immunotherapy sensitizers have arisen as approaches focused on the synergistic effects of immunotherapy combination, or the combination of immunotherapy and other treatment modalities, such as chemotherapy or radiation therapy. Concomitantly, novel immunotherapy modalities are also in development. Approaches focusing from the tumor intrinsic pathways to the tumor microenvironment and ex-vivo interventions, such as CAR-T cell therapies and tumor-infiltrating lymphocytes are important examples. Although many of those interventions were initially envisioned as standalone options, their combination has demonstrated promising results in early-phase in vitro studies and clinical trials. The possibility of coupling different immunotherapy modalities, as well as with other techniques, further strengthen the concept of sensitizers, allowing for deeper and more robust responses in cancer treatment. This review aims to present an overview of the concepts of these sensitizing mechanisms that are the basis for the synergistic effects of immunotherapy combination, or the combination of immunotherapy and a multitude of therapeutic strategies. Novel immunotherapy modalities are also presented, focusing on the potential of combining them with sensitizer interventions. Understanding the complexity underlying these principles may be the key for future breakthroughs and improved patient outcomes.

Efficacy and clinical potential of phage therapy in treating methicillin-resistant Staphylococcus aureus (MRSA) infections: A review.

Staphylococcus aureus infections have already presented a substantial public health challenge, encompassing different clinical manifestations, ranging from bacteremia to sepsis and multi-organ failures. Among these infections, methicillin-resistant S. aureus (MRSA) is particularly alarming due to its well-documented resistance to multiple classes of antibiotics, contributing significantly to global mortality rates. Consequently, the urgent need for effective treatment options has prompted a growing interest in exploring phage therapy as a potential non-antibiotic treatment against MRSA infections. Phages represent a class of highly specific bacterial viruses known for their ability to infect certain bacterial strains. This review paper explores the clinical potential of phages as a treatment for MRSA infections due to their low toxicity and auto-dosing capabilities. The paper also discusses the synergistic effect of phage-antibiotic combination (PAC) and the promising results from in vitro and animal model studies, which could lead to extensive human clinical trials. However, clinicians need to establish and adhere tostandard protocols governing phage administration and implementation. Prominent clinical trials areneeded to develop and advance phage therapy as a non-antibiotic therapy intervention, meeting regulatory guidelines, logistical requirements, and ethical considerations, potentially revolutionizing the treatment of MRSA infections.

Interfacing Ag2S Nanoparticles and MoS2 Nanosheets on Polypyrrole Nanotubes with Enhanced Catalytic Performance.

The tubular architecture with multiple components can bring synergistic effects to improve the enzyme-like activity of molybdenum-based nanomaterials. Here, a facile polypyrrole (PPy)-protected hydrothermal sulfidation process was implemented to engineer MoS2/Ag2S heterointerfaces encapsulated in one-dimensional (1D) PPy nanotubes with MoO3@Ag nanorods as the self-sacrificing precursor. Notably, the sulfidation treatment led to the generation of MoS2 nanosheets (NSs) and Ag2S nanoparticles (NPs) and the creation of a tubular structure with a "kill three birds with one stone" role. The Ag2S/MoS2@PPy nanotubes showed the synergistic combined effects of Ag2S NPs, MoS2 NSs, and the 1D tube-like nanostructure. Based on the synergistic effects from these multiple components and the tubular structure, Ag2S/MoS2@PPy nanocomposites were used as a colorimetric sensing platform for detecting H2O2. Moreover, the reduction of 4-nitrophenol (4-NP) revealed excellent catalytic activity in the presence of NaBH4 and Ag2S/MoS2@PPy nanocomposites. This work highlights the effects of MoS2/Ag2S heterointerfaces and the hierarchical tubular structure in catalysis, thereby providing a new avenue for reducing 4-NP and the enzyme-like catalytic field.

Synergistic effects of thyme and oregano essential oil combinations for enhanced functional properties of sericin/pectin film

This work aimed to assess the synergistic antibacterial effects of thyme and oregano essential oils in various ratios (thyme:oregano; 10:0, 8:2, 6:4, 4:6, 2:8, 10:0). We hypothesized that the synergistic combination of thyme and oregano essential oils can be effectively incorporated into sericin/pectin film to enhance its functional properties. Among the combinations tested, the mixture of thyme/oregano essential oil (TOE) at an 8:2 ratio exhibited the most potent synergistic activity against P. aeruginosa and S. aureus, with fractional inhibitory concentration index (FICindex) of 0.9. In this combination, thymol constituting 51.83 % of TOE (8:2), was the predominant component. TOE at an 8:2 ratio was selected to incorporate into sericin/pectin film. Different concentrations of TOE (0.8 %, 1.2 % and 1.6 %) were applied to evaluate their impact on film properties compared to a film without essential oil (control). It was found that increasing TOE concentration (control; 0 %) to 1.6 % reduced film moisture content (from 21.53 % to 16.91 %), decreased yellowness (from 18.24 to 15.92), diminished gloss (from 63.79 to 11.18), lowered swelling index (from 1.24 to 0.98), and reduced tensile strength (from 9.70 to 4.14 MPa). However, the addition of TOE showed higher film total phenolic content (8.59–31.53 mg gallic acid/g dry sample) and increased antioxidant activity (0.99–3.68 μmol Trolox /g dry sample). Moreover, the film with 1.2 % and 1.6 % of thyme/oregano essential oil exhibited inhibitory effects against all tested bacteria. Therefore, the thyme/oregano essential oil combination can provide the desirable physicochemical properties of the sericin/pectin film, as well as its antibacterial and antioxidant activities, making it a promising alternative for food packaging material applications.

The anti-staphylococcal fusidic acid as an efflux pump inhibitor combined with fluconazole against vaginal candidiasis in mouse model

BackgroundCandida albicans is the most common fungus that causes vaginal candidiasis in immunocompetent women and catastrophic infections in immunocompromised patients. The treatment of such infections is hindered due to the increasing emergence of resistance to azoles in C. albicans. New treatment approaches are needed to combat candidiasis especially in the dwindled supply of new effective and safe antifungals. The resistance to azoles is mainly attributed to export of azoles outside the cells by means of the efflux pump that confers cross resistance to all azoles including fluconazole (FLC).ObjectivesThis study aimed to investigate the possible efflux pump inhibiting activity of fusidic acid (FA) in C. albicans resistant isolates and the potential use of Fusidic acid in combination with fluconazole to potentiate the antifungal activity of fluconazole to restore its activity in the resistant C. albicans isolates.MethodsThe resistance of C. albicans isolates was assessed by determination of minimum inhibitory concentration. The effect of Fusidic acid at sub-inhibitory concentration on efflux activity was assayed by rhodamine 6G efflux assay and intracellular accumulation. Mice model studies were conducted to evaluate the anti-efflux activity of Fusidic acid and its synergistic effects in combination with fluconazole. Impact of Fusidic acid on ergosterol biosynthesis was quantified. The synergy of fluconazole when combined with Fusidic acid was investigated by determination of minimum inhibitory concentration. The cytotoxicity of Fusidic acid was tested against erythrocytes. The effect of Fusidic acid on efflux pumps was tested at the molecular level by real-time PCR and in silico study. In vivo vulvovaginitis mice model was used to confirm the activity of the combination in treating vulvovaginal candidiasis.ResultsFusidic acid showed efflux inhibiting activity as it increased the accumulation of rhodamine 6G, a substrate for ABC-efflux transporter, and decreased its efflux in C. albicans cells. The antifungal activity of fluconazole was synergized when combined with Fusidic acid. Fusidic acid exerted only minimal cytotoxicity on human erythrocytes indicating its safety. The FA efflux inhibitory activity could be owed to its ability to interfere with efflux protein transporters as revealed by docking studies and downregulation of the efflux-encoding genes of both ABC transporters and MFS superfamily. Moreover, in vivo mice model showed that using fluconazole-fusidic acid combination by vaginal route enhanced fluconazole antifungal activity as shown by lowered fungal burden and a negligible histopathological change in vaginal tissue.ConclusionThe current findings highlight FA’s potential as a potential adjuvant to FLC in the treatment of vulvovaginal candidiasis.

Research on different compound combinations of Realgar-Indigo naturalis formula to reverse acute promyelocytic leukemia arsenic resistance by regulating autophagy through mTOR pathway

Ethnopharmacological relevanceIn China, the Chinese patent drug Realgar-Indigo naturalis Formula (RIF) is utilized for the therapy of acute promyelocytic leukemia (APL). Comprising four traditional Chinese herb—Realgar, Indigo naturalis, Salvia miltiorrhiza, and Pseudostellaria heterophylla—it notably includes tetra-arsenic tetra-sulfide, indirubin, tanshinone IIa, and total saponins of Radix Pseudostellariae as its primary active components. Due to its arsenic content, RIF distinctly contributes to the therapy for APL. However, the challenge of arsenic resistance in APL patients complicates the clinical use of arsenic agents. Interestingly, RIF demonstrates a high remission rate in APL patients, suggesting that its efficacy is not significantly compromised by arsenic resistance. Yet, the current state of research on RIF's ability to reverse arsenic resistance remains unclear. Aim of the studyTo investigate the mechanism of different combinations of the compound of RIF in reversing arsenic resistance in APL. Materials and methodsThe present study utilized the arsenic-resistant HL60-PMLA216V-RARα cell line to investigate the effects of various RIF compounds, namely tetra-arsenic tetra-sulfide (A), indirubin (I), tanshinone IIa (T), and total saponins of Radix Pseudostellariae (S). The assessment of cell viability, observation of cell morphology, and evaluation of cell apoptosis were performed. Furthermore, the mitochondrial membrane potential, changes in the levels of PMLA216V-RARα, apoptosis-related factors, and the PI3K/AKT/mTOR pathway were examined, along with autophagy in all experimental groups. Meanwhile, we observed the changes about autophagy after blocking the PI3K or mTOR pathway. ResultsTanshinone IIa, indirubin and total saponins of Radix Pseudostellariae could enhance the effect of tetra-arsenic tetra-sulfide down-regulating PMLA216V-RARα, and the mechanism was suggested to be related to inhibiting mTOR pathway to activate autophagy. ConclusionsWe illustrated that the synergistic effect of different compound combinations of RIF can regulate autophagy through the mTOR pathway, enhance cell apoptosis, and degrade arsenic-resistant PMLA216V-RARα.

Novel nitroxoline derivative combating resistant bacterial infections through outer membrane disruption and competitive NDM-1 inhibition

ABSTRACT New Delhi metallo-β-lactamase-1 (NDM-1) has rapidly disseminated worldwide, leading to multidrug resistance and worse clinical prognosis. Designing and developing effective NDM-1 inhibitors is a critical and urgent challenge. In this study, we constructed a library of long-lasting nitroxoline derivatives and identified ASN-1733 as a promising dual-functional antibiotic. ASN-1733 can effectively compete for Ca2+ on the bacterial surface, causing the detachment of lipopolysaccharides (LPS), thereby compromising the outer membrane integrity and permeability and exhibiting broad-spectrum bactericidal activity. Moreover, ASN-1733 demonstrated wider therapeutic applications than nitroxoline in mouse sepsis, thigh and mild abdominal infections. Furthermore, ASN-1733 can effectively inhibit the hydrolytic capability of NDM-1 and exhibits synergistic killing effects in combination with meropenem against NDM-1 positive bacteria. Mechanistic studies using enzymatic experiments and computer simulations revealed that ASN-1733 can bind to key residues on Loop10 of NDM-1, hindering substrate entry into the enzyme's active site and achieving potent inhibitory activity (Ki = 0.22 µM), even in the presence of excessive Zn2+. These findings elucidate the antibacterial mechanism of nitroxoline and its derivatives, expand their potential application in the field of antibacterial agents and provide new insights into the development of novel NDM-1 inhibitors.

KDM5C-Mediated Recruitment of BRD4 to Chromatin Regulates Enhancer Activation and BET Inhibitor Sensitivity.

BRD4 is recruited to enhancers in a bromodomain-independent manner by binding KDM5C and stimulates KDM5C H3K4 demethylase activity, leading to synergistic effects of BET and KDM5C inhibitor combinations in cancer.

Repurposing proteasome inhibitors for improved treatment of triple-negative breast cancer

Triple-negative breast cancer (TNBC) is associated with poor prognosis and limited treatment options due to the lack of important receptors (estrogen receptor [ER], progesterone receptor [PR], and human epidermal growth factor receptor 2 [HER2]) used for targeted therapy. However, high-throughput in vitro drug screening of cell lines is a powerful tool for identifying effective drugs for a disease. Here, we determine the intrinsic chemosensitivity of TNBC cell lines to proteasome inhibitors (PIs), thereby identifying potentially potent 2-drug combinations for TNBC. Eight TNBC cell lines (BT-549, CAL-148, HCC1806, HCC38, HCC70, MDA-MB-436, MDA-MB-453, and MDA-MB-468) and two controls (MCF-10A and MCF-7) were first exposed to 18 drugs (11 PIs and 7 clinically relevant chemotherapeutic agents) as monotherapy, followed by prediction of potent 2-drug combinations using the IDACombo pipeline. The synergistic effects of the 2-drug combinations were evaluated with SynergyFinder in four TNBC cell lines (CAL-148, HCC1806, HCC38, and MDA-MB-468) and three controls (BT-474, MCF-7, and T47D) in vitro, followed by further evaluation of tumor regression in zebrafish tumor models established using HCC1806 and MCF-7 cells. Monotherapy identified nine effective drugs (bortezomib, carfilzomib, cisplatin, delanzomib, docetaxel, epoxomicin, MLN-2238, MLN-9708, and nedaplatin) across all cell lines. PIs (e.g., bortezomib, delanzomib, and epoxomicin) were highly potent drugs in TNBC cells, of which bortezomib and delanzomib inhibited the chymotrypsin-like activity of the 20 S proteasome by 100% at 10 µM. Moreover, several potent 2-drug combinations (e.g., bortezomib+nedaplatin and epoxomicin+epirubicin) that killed virtually 100% of cells were also identified. Although HCC1806- and MCF-7-derived xenografts treated with bortezomib+nedaplatin and carboplatin+paclitaxel were smaller, HCC1806 cells frequently metastasized to the trunk region. Taken together, we show that PIs used in combination with platinum agents or topoisomerase inhibitors exhibit increased efficiency with almost 100% inhibition in TNBC cell lines, indicating that PIs are therefore promising compounds to use as combination therapy for TNBC.

Harnessing the cytotoxic granule exocytosis to augment the efficacy of T-cell-engaging bispecific antibody therapy.

T-cell-engaging bispecific antibody (T-BsAb, also known as BiTE) therapy has emerged as a powerful therapeutic modality against multiple myeloma. Given that T-BsAb therapy redirects endogenous T cells to eliminate tumor cells, reinvigorating dysfunctional T cells may be a potential approach to improve the efficacy of T-BsAb. While various immunostimulatory cytokines can potentiate effector T-cell functions, the optimal cytokine treatment for T-BsAb therapy is yet to be established, partly due to a concern of cytokine release syndrome driven by aberrant interferon (IFN)-γ production. Here, we functionally screen immunostimulatory cytokines to determine an ideal combination partner for T-BsAb therapy. This approach reveals interleukin (IL)-21 as a potential immunostimulatory cytokine with the ability to augment T-BsAb-mediated release of granzyme B and perforin, without increasing IFN-γ release. Transcriptome profiling and functional characterization strongly support that IL-21 selectively targets the cytotoxic granule exocytosis pathway, but not pro-inflammatory responses. Notably, IL-21 modulates multiple steps of cytotoxic effector functions including upregulation of co-activating CD226 receptor, increasing cytotoxic granules, and promoting cytotoxic granule delivery at the immunological synapse. Indeed, T-BsAb-mediated myeloma killing is cytotoxic granule-dependent, and IL-21 priming significantly augments cytotoxic activities. Furthermore, in vivo IL-21 treatment induces cytotoxic effector reprogramming in bone marrow T cells, showing synergistic anti-myeloma effects in combination with T-BsAb therapy. Together, harnessing the cytotoxic granule exocytosis pathway by IL-21 may be a potential approach to achieve better responses by T-BsAb therapy.

Patient‐derived Immunocompetent Tumor Organoids: A Platform for Chemotherapy Evaluation in the Context of T‐cell Recognition**

AbstractMost of the anticancer compounds synthesized by chemists are primarily evaluated for their direct cytotoxic effects at the cellular level, often overlooking the critical role of the immune system. In this study, we developed a patient‐derived, T‐cell‐retaining tumor organoid model that allows us to evaluate the anticancer efficacy of chemical drugs under the synergistic paradigm of antigen‐specific T‐cell‐dependent killing, which may reveal the missed drug hits in the simple cytotoxic assay. We evaluated clinically approved platinum (Pt) drugs and a custom library of twenty‐eight PtIV compounds. We observed low direct cytotoxicity of Pt drugs, but variable synergistic effects in combination with immune checkpoint inhibitors (ICIs). In contrast, the majority of PtIV compounds exhibited potent tumor‐killing capabilities. Interestingly, several PtIV compounds went beyond direct tumor killing and showed significant immunosynergistic effects with ICIs, outstanding at sub‐micromolar concentrations. Among these, Pt‐19, PtIV compounds with cinnamate axial ligands, emerged as the most therapeutically potent, demonstrating pronounced immunosynergistic effects by promoting the release of cytotoxic cytokines, activating immune‐related pathways and enhancing T cell receptor (TCR) clonal expansion. Overall, this initiative marks the first use of patient‐derived immunocompetent tumor organoids to explore and study chemotherapy, advancing their path toward more effective small molecule drug discovery.

Patient-derived Immunocompetent Tumor Organoids: A Platform for Chemotherapy Evaluation in the Context of T-cell Recognition.

Most of the anticancer compounds synthesized by chemists are primarily evaluated for their direct cytotoxic effects at the cellular level, often overlooking the critical role of the immune system. In this study, we developed a patient-derived, T-cell-retaining tumor organoid model that allows us to evaluate the anticancer efficacy of chemical drugs under the synergistic paradigm of antigen-specific T-cell-dependent killing, which may reveal the missed drug hits in the simple cytotoxic assay. We evaluated clinically approved platinum (Pt) drugs and a custom library of twenty-eight PtIV compounds. We observed low direct cytotoxicity of Pt drugs, but variable synergistic effects in combination with immune checkpoint inhibitors (ICIs). In contrast, the majority of PtIV compounds exhibited potent tumor-killing capabilities. Interestingly, several PtIV compounds went beyond direct tumor killing and showed significant immunosynergistic effects with ICIs, outstanding at sub-micromolar concentrations. Among these, Pt-19, PtIV compounds with cinnamate axial ligands, emerged as the most therapeutically potent, demonstrating pronounced immunosynergistic effects by promoting the release of cytotoxic cytokines, activating immune-related pathways and enhancing T cell receptor (TCR) clonal expansion. Overall, this initiative marks the first use of patient-derived immunocompetent tumor organoids to explore and study chemotherapy, advancing their path toward more effective small molecule drug discovery.

Photodynamic Therapy as a Desirable Approach in the Treatment of Colorectal Cancer, with Special Focus on Photodynamic Nanotherapeutics in Immunotherapy.

Colorectal cancer (CRC) is one of the most prevalent malignancies worldwide; however, there is not a convincing treatment for this disease. Limitations of conventional CRC therapies force scientists to develop novel treatment concepts for both primary care alongside adjuvant therapy. Photodynamic therapy (PDT) has been introduced as a promising therapeutic procedure for CRC mediated through theranostic principle in which special dyes, photosensitizers (PSs), are excited by near-infrared (NIR) and visible light. Recent studies showed that PDT has synergistic effects in combination with chemotherapy or immunotherapy in the treatment of CRC patients. Of note, nanoformulation of PS or immunotherapeutic agents could augment the PDT effectiveness. In this review, we summarize PDT application in CRC management with a special focus on the nanoparticles-based delivery system from the perspective of targeting deeper CRC and increased PDT efficiency, which could provide a desirable approach for clinical translation.