Targeting multidrug resistance-associated protein 1 (MRP1)-expressing cancers: Beyond pharmacological inhibition

Inhibition of ABCG2 by SCO-101 Enhances Chemotherapy Efficacy in Cancer

Chemotherapy resistance, particularly multidrug resistance (MDR), remains a significant barrier to effective cancer treatment, leading to high mortality rates. The development of novel therapeutic strategies targeting key molecular mechanisms to counteract drug resistance is thus an urgent clinical need. In this study, we evaluated the potential of the small molecule SCO-101 to restore chemotherapy sensitivity in drug-resistant cancer cells. Using in silico and in vitro models such as molecular docking, cell viability, colony formation, dye efflux, transporter assays and chemotherapy retention, we assessed the impact of SCO-101 on drug retention and response in several drug-resistant cancer cells. SCO-101 was found to inhibit the activity of breast cancer resistance protein (BCRP/ABCG2) and UDP Glucuronosyltransferase Family 1 Member A1 (UGT1A1), two key proteins involved in drug resistance by cellular drug excretion and drug metabolism. Our results demonstrate that inhibition of these proteins by SCO-101 leads to increased intracellular drug accumulation, enhancing the cytotoxic effects of chemotherapy agents. Additionally, we identified a strong correlation between high ABCG2 expression and MDR in non-drug-resistant models, where cells exhibiting elevated ABCG2 levels displayed chemotherapy resistance, which was effectively reversed by SCO-101 co-treatment. These findings highlight the therapeutic potential of SCO-101 in overcoming MDR by inhibiting drug efflux mechanisms and metabolism, thereby enhancing chemotherapy efficacy. SCO-101 is currently undergoing clinical trials as an orally administered drug and is considered a promising strategy for improving cancer treatment outcomes in patients with drug-resistant tumors.

A New Histology-Based Prognostic Index for Acute Myeloid Leukemia: Preliminary Results for the "AML Urayasu Classification"

Background: This study was aimed at elucidating the mechanisms underlying the development of treatment resistance in patients with acute myeloid leukemia (AML) other than M3 myeloid leukemia in order to devise ways to overcome treatment resistance and improve the treatment outcomes in these patients. Methods: For this study, we randomly selected 35 patients with AML who had received combined cytarabine plus idarubicin treatment for new-onset AML at our hospital. We performed immunohistochemical analysis of biopsy specimens obtained from the patients to investigate the expressions of 23 treatment-resistance-related proteins, and retrospectively analyzed the correlations between the expression profiles of the resistance proteins and the patient survival. Results: The following four proteins were identified as being particularly significant in relation to treatment resistance and patient prognosis: (1) p53; (2) multidrug resistance-associated protein 1 (MRP1; idarubicin extracellular efflux pump); (3) aldo-keto reductase family 1 member B10 (AKR1B10; idarubicin-inactivating enzyme); and (4) AKR1B1 (competitive inhibitor of AKR1B10). Based on our findings, we propose the following Urayasu classification for AML, which we believe would be very useful for accurately stratifying patients with AML according to the predicted prognosis: Group 1 (n = 22, 63%): p53(-)/MRP1(-) associated with AKR1B10(+)/AKR1B1(+) or AKR1B10(-)/AKR1B1(-); 5-year overall survival (OS), 82%-100%; Group 2 (n = 9, 26%): p53(-)/MRP1(-) associated with AKR1B10(+)/AKR1B1(-); 5-year OS, 68%; Group 3 (n = 4, 11%): p53(+) or MRP1(+); median survival, 12-14 months; 2-year OS, 0%. Conclusions: The Urayasu classification for AML is useful for predicting the prognosis of patients with AML. Group 1 in this classification included twice as many patients as that included in the Favorable prognosis group in the AML prognostic classification proposed by the European Leukemia Net. As the Urayasu classification for AML is based on the mechanisms of resistance to chemotherapy, it is not only useful for prognostic stratification of the patients, but also provides insights for developing more effective treatments for AML.

Isoquinolinequinone N-oxides with diverging mechanisms of action induce collateral sensitivity against multidrug resistant cancer cells

Multidrug resistance (MDR) is a major challenge in cancer research. Collateral sensitizers, compounds that exploit the enhanced defense mechanisms of MDR cells as weaknesses, are a proposed strategy to overcome MDR. Our previous work reported the synthesis of two novel Isoquinolinequinone (IQQ) N-oxides that induce collateral sensitivity in MDR ABCB1-overexpressing non-small cell lung cancer (NSCLC) and colorectal cancer cells. Herein, we aimed to investigate underlying mechanisms of antitumor and collateral sensitivity activity of these compounds. We evaluated their effect on cancer cell viability, proliferation, cell cycle profile, and studied their cytotoxicity in non-tumorigenic cells. Their antitumor effect was further studied using NSCLC and colorectal cancer MDR spheroids. To understand underlying collateral sensitivity mechanisms, we assessed the effect on rhodamine-123 accumulation, ROS production, GSH/GSSG balance and expression of key proteins associated with metabolism and redox balance. Both compounds reduced the viability of MDR cells, as 2D cultures or as spheroids, without decreasing the growth of a human nontumorigenic cell line, and increased rhodamine-123 accumulation in MDR NCI-H460/R cells. Moreover, RK2 increased ROS, disrupted GSH balance, and altered expression of proteins associated with oxidative stress protection, particularly in NCI-H460/R cells. The collateral sensitivity effect of RK3 could not be attributed to redox balance disruption, but increased IDH1 expression following treatment suggests a potential metabolic shift in MDR cells. These findings highlight RK2 and RK3 as promising candidates for next stages of drug development. Their distinct mechanisms of action could lead to therapeutic solutions for MDR-related cancers, specifically linked to ABCB1 overexpression.

Fucosyltransferase 4 upregulates P-gp expression for chemoresistance via NF-κB signaling pathway

BACKGROUND

Multidrug resistance (MDR) poses a significant obstacle to developing chemotherapeutic treatments. In previous studies using a traditional model of adriamycin resistance (ADR) with K562 cells, we demonstrated that N-acetylglucosaminyltransferase III (GnT-III) expression negatively regulates chemoresistance. Additionally, we observed that fucosylation levels were increased in the ADR cells.

METHOD

Fucosylation levels were determined using lectin blot, western blot, and flow cytometry. Gene expression levels were analyzed via qPCR. We generated a FUT4 knockout (KO) ADR cell line using CRISPR/Cas9 technology. Cytotoxicity and drug efflux assays were conducted to evaluate chemotherapy tolerance.

RESULTS

The expression levels of FUT4 and its products, the LeX antigens, were significantly upregulated in the ADR cells compared to the parental K562 cells. The FUT4 KO reduced the elevated levels of P-glycoprotein (P-gp) found in ADR cells and exhibited increased sensitivity to chemotherapeutic drugs. Furthermore, restoring FUT4 expression in the KO cells effectively reversed P-gp expression, drug efflux, and chemoresistance. Given the critical role of the NF-κB pathway in P-gp expression, we investigated NF-κB signaling and found that the phosphorylation levels of p65 were significantly increased in the ADR cells but were downregulated in the FUT4 KO cells. Furthermore, the restoration of FUT4 rescued the phosphorylation levels of p65.

CONCLUSIONS

FUT4 specifically upregulates P-gp expression related to chemoresistance through the NF-κB signaling pathway.

GENERAL SIGNIFICANCE

This study highlights the importance of FUT4 in chemoresistance and suggests it may serve as a promising target for combating MDR.

siRNA-based therapy for overcoming drug resistance in human solid tumours; molecular and immunological approaches

RNA interference (RNAi) is a primordial biological process that protects against external intrusion. SiRNA has the potential to selectively silence disease-related genes in a sequence-specific way, thus offering a promising therapeutic approach. The efficacy of siRNA-based therapies in cancer treatment has gained significant recognition due to multiple studies demonstrating its ability to effectively suppress cancer cells' growth and multiplication. Moreover, siRNA-based medicines have shown considerable promise in enhancing the sensitivity of cancer cells to chemotherapy and other treatment methods by suppressing genes that play a role in the development of drug resistance. Exploring and identifying functional genes linked to cancer cell characteristics and drug resistance is crucial for developing effective siRNAs for cancer treatment and advancing targeted and personalized therapeutics. Targeting and silencing genes in charge of resistance mechanisms, such as those involved in drug efflux, cell survival, or DNA repair, is possible with siRNA therapy in the context of drug resistance, especially cancer. Through inhibiting these genes, siRNA therapy can prevent resistance and restore the efficacy of traditional medications. This review addresses the potential of siRNAs in addressing drug resistance in human tumours, opening up new possibilities in cancer therapy. This review article offers a non-systematic summary of how different siRNA types contribute to cancer cells' treatment resistance. Using pertinent keywords, sources were chosen from reliable databases, including PubMed, Scopus, and Google Scholar. The review covered essential papers in this area and those that mainly addressed the function of siRNA in drug resistance. The articles examined in connection with the title of this review were primarily published from 2020 onward and are based on in vitro studies. Furthermore, this article examines the potential barriers and prospective perspectives of siRNA therapies.

Bacterial Proteins and Peptides as Potential Anticancer Agents: A Novel Search for Protein-based Therapeutics

Tumor diseases remain among the world's primary causes of death despite substantial advances in cancer diagnosis and treatment. The adverse chemotherapy problems and sensitivity towards drugs for some cancer types are among the most promising challenges in modern treatment. Finding new anti-cancer agents and drugs is, therefore, essential. A significant class of biologically active substances and prospective medications against cancer is comprised of bacterial proteins and peptides. Among these bacterial peptides, some of them, such as anti-cancer antibiotics and many toxins like diphtheria are widely being used in the treatment of cancer. In contrast, the remaining bacterial peptides are either in clinical trials or under research in vitro studies. This study includes the most recent information on the characteristics and mechanism of action of the bacterial peptides that have anti-cancer activities, some of which are now being employed in cancer therapy while some are still undergoing research.

Comprehensive review of drug resistance in mammalian cancer stem cells: implications for cancer therapy

Cancer remains a significant global challenge, and despite the numerous strategies developed to advance cancer therapy, an effective cure for metastatic cancer remains elusive. A major hurdle in treatment success is the ability of cancer cells, particularly cancer stem cells (CSCs), to resist therapy. These CSCs possess unique abilities, including self-renewal, differentiation, and repair, which drive tumor progression and chemotherapy resistance. The resilience of CSCs is linked to certain signaling pathways. Tumors with pathway-dependent CSCs often develop genetic resistance, whereas those with pathway-independent CSCs undergo epigenetic changes that affect gene regulation. CSCs can evade cytotoxic drugs, radiation, and apoptosis by increasing drug efflux transporter activity and activating survival mechanisms. Future research should prioritize the identification of new biomarkers and signaling molecules to better understand drug resistance. The use of cutting-edge approaches, such as bioinformatics, genomics, proteomics, and nanotechnology, offers potential solutions to this challenge. Key strategies include developing targeted therapies, employing nanocarriers for precise drug delivery, and focusing on CSC-targeted pathways such as the Wnt, Notch, and Hedgehog pathways. Additionally, investigating multitarget inhibitors, immunotherapy, and nanodrug delivery systems is critical for overcoming drug resistance in cancer cells.

Deep learning-based prediction of chemical accumulation in a pathogenic mycobacterium

Drugs must accumulate at their target site to be effective, and inadequate uptake of drugs is a substantial barrier to the design of potent therapies. This is particularly true in the development of antibiotics, as bacteria possess numerous barriers to prevent chemical uptake. Designing compounds that circumvent bacterial barriers and accumulate to high levels in cells could dramatically improve the success rate of antibiotic candidates. However, a comprehensive understanding of which chemical structures promote or prevent drug uptake is currently lacking. Here we use liquid chromatography-mass spectrometry to measure accumulation of 1528 approved drugs in Mycobacterium abscessus, a highly drug-resistant, opportunistic pathogen. We find that simple chemical properties fail to effectively predict drug accumulation in mycobacteria. Instead, we use our data to train deep learning models that predict drug accumulation in M. abscessus with high accuracy, including for chemically diverse compounds not included in our original drug library. We find that differential drug uptake is a critical determinant of the efficacy of drugs currently in development and can identify compounds which accumulate well and have antibacterial activity in M. abscessus. These predictive algorithms can be an important complement to chemical synthesis and accumulation assays in the evaluation of drug candidates.

SRC kinase drives multidrug resistance induced by KRAS-G12C inhibition

Direct targeting of the KRAS-G12C-mutant protein using covalent inhibitors (G12Ci) acts on human non-small cell lung cancer (NSCLC). However, drug resistance is an emerging concern in this approach. Here, we show that MRTX849, a covalent inhibitor targeting the KRAS-G12C mutation, leads to the reactivation of the mitogen-activated protein kinase signaling pathway in MRTX849-resistant NSCLC and pancreatic ductal adenocarcinoma. A genome-wide CRISPR screen revealed that the adenosine triphosphate binding cassette transporter ABCC1 mediates MRTX849 resistance. Functional studies demonstrated that the transcription factor JUN drives ABCC1 expression, resulting in multidrug resistance. An unbiased drug screen identified the tyrosine kinase inhibitor dasatinib that potentiates MRTX849 efficacy by inhibiting SRC-dependent JUN activation, avoiding multidrug resistance and tumor suppression in vitro as well as in suitable preclinical mouse models and patient-derived organoids. SRC inhibitors (DGY-06-116, dasatinib, and bosutinib) also exhibit synergistic effects with MRTX849 in eliminating various tumor cell lines carrying KRAS-G12C mutations. Thus, SRC inhibitors amplify the therapeutic utility of G12Ci.

Aryl Hydrocarbon Receptor Alleviates Hepatic Fibrosis by Inducing Hepatic Stellate Cell Ferroptosis

Liver injury-induced activation of hepatic stellate cells (HSCs) is a crucial step in the progression of liver fibrosis. The aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor, is highly expressed in the liver. However, the role of AHR in liver fibrosis remains controversial. Our study revealed that the nontoxic ligand YH439 directly activated the AHR and regulated the expression of multidrug-resistant protein 1 (Mrp1) in mouse hepatic stellate cells (mHSCs), thereby diminishing the antioxidant capacity of mHSCs by promoting GSH efflux, and specifically inducing mHSCs ferroptosis without affecting hepatocytes. In a chronic liver fibrosis model, YH439 activated AHR to promote mHSC ferroptosis without causing hepatocyte ferroptosis, thereby alleviating liver fibrosis. Conclusively, this study shows that AHR alleviates liver fibrosis in mice by selectively inducing mHSC ferroptosis without causing hepatocyte ferroptosis and suggests that AHR is a potential target for the treatment of liver fibrosis.

MiRNAs function in the development of resistance against doxorubicin in cancer cells: targeting ABC transporters

Resistance to chemotherapeutic agents poses a significant challenge in cancer treatment, particularly with doxorubicin, a widely used drug for various cancers, including breast cancer, leukaemia, osteosarcoma, and gastrointestinal cancers. This review aims to elucidate the critical role of microRNAs (miRNAs) in the development of doxorubicin resistance, focusing on their interactions with ATP-binding cassette (ABC) transporters. Despite extensive research, the molecular mechanisms governing doxorubicin resistance still need to be completed, particularly regarding the regulatory influence of miRNAs on ABC transporter expression. By analyzing current literature, this review identifies a notable gap: the lack of comprehensive insight into how specific miRNAs modulate the expression and activity of ABC transporters in cancer cells, contributing to doxorubicin resistance. We systematically examine recent findings on the interplay between miRNAs and ABC transporters, providing a detailed assessment of potential therapeutic strategies that leverage miRNA modulation to overcome drug resistance. Ultimately, this review underscores the significance of integrating miRNA research into existing therapeutic frameworks to enhance the efficacy of doxorubicin in cancer treatment.

ATP-Binding Cassette and Solute Carrier Transporters: Understanding Their Mechanisms and Drug Modulation Through Structural and Modeling Approaches

The ATP-binding cassette (ABC) and solute carrier (SLC) transporters play pivotal roles in cellular transport mechanisms, influencing a wide range of physiological processes and impacting various medical conditions. Recent advancements in structural biology and computational modeling have provided significant insights into their function and regulation. This review provides an overview of the current knowledge of human ABC and SLC transporters, emphasizing their structural and functional relationships, transport mechanisms, and the contribution of computational approaches to their understanding. Current challenges and promising future research and methodological directions are also discussed.

Unraveling the secrets: Evolution of resistance mediated by membrane proteins

Membrane protein-mediated resistance is a multidisciplinary challenge that spans fields such as medicine, agriculture, and environmental science. Understanding its complexity and devising innovative strategies are crucial for treating diseases like cancer and managing resistant pests in agriculture. This paper explores the dual nature of resistance mechanisms across different organisms: On one hand, animals, bacteria, fungi, plants, and insects exhibit convergent evolution, leading to the development of similar resistance mechanisms. On the other hand, influenced by diverse environmental pressures and structural differences among organisms, they also demonstrate divergent resistance characteristics. Membrane protein-mediated resistance mechanisms are prevalent across animals, bacteria, fungi, plants, and insects, reflecting their shared survival strategies evolved through convergent evolution to address similar survival challenges. However, variations in ecological environments and biological characteristics result in differing responses to resistance. Therefore, examining these differences not only enhances our understanding of adaptive resistance mechanisms but also provides crucial theoretical support and insights for addressing drug resistance and advancing pharmaceutical development.

lncRNAs: New players of cancer drug resistance via targeting ABC transporters

Cancer drug resistance poses a significant obstacle to successful chemotherapy, primarily driven by the activity of ATP-binding cassette (ABC) transporters, which actively efflux chemotherapeutic agents from cancer cells, reducing their intracellular concentrations and therapeutic efficacy. Recent studies have highlighted the pivotal role of long noncoding RNAs (lncRNAs) in regulating this resistance, positioning them as crucial modulators of ABC transporter function. lncRNAs, once considered transcriptional noise, are now recognized for their complex regulatory capabilities at various cellular levels, including chromatin modification, transcription, and post-transcriptional processing. This review synthesizes current research demonstrating how lncRNAs influence cancer drug resistance by modulating the expression and activity of ABC transporters. lncRNAs can act as molecular sponges, sequestering microRNAs that would otherwise downregulate ABC transporter genes. Additionally, they can alter the epigenetic landscape of these genes, affecting their transcriptional activity. Mechanistic insights reveal that lncRNAs contribute to the activity of ABC transporters, thereby altering the efflux of chemotherapeutic drugs and promoting drug resistance. Understanding these interactions provides a new perspective on the molecular basis of chemoresistance, emphasizing the regulatory network of lncRNAs and ABC transporters. This knowledge not only deepens our understanding of the biological mechanisms underlying drug resistance but also suggests novel therapeutic strategies. In conclusion, the intricate interplay between lncRNAs and ABC transporters is crucial for developing innovative solutions to combat cancer drug resistance, underscoring the importance of continued research in this field.

Brain-to-blood transport of fluorescein in vitro

Investigating blood-brain barrier (BBB) dysfunction has become a pre-clinical and clinical research focus as it accompanies many neurological disorders. Nevertheless, knowledge of how diagnostic BBB tracers cross the endothelium from blood-to-brain or vice versa often remains incomplete. In particular, brain-to-blood transport (efflux) may reduce tracer extravasation of intravascularly (i.v.) applied tracers. Conversely, impaired efflux could mimic phenotypic extravasation. Both processes would affect conclusions on BBB properties primarily attributed to blood-to-brain leakage. Here, we specifically investigated efflux of fluorescent BBB tracers, focusing on the most common non-toxic marker, sodium fluorescein, which is applicable in patients. We used acute neocortical slices from mice and applied fluorescein, sulforhodamine-B, rhodamine-123, FITC dextran to the artificial cerebrospinal fluid. Anionic low molecular weight (MW) fluorescein and sulforhodamine-B, but not ~ 10-fold larger FITC-dextran and cationic low MW rhodamine-123, showed efflux into the lumen of blood vessels. Our data suggest that fluorescein efflux depends on organic anion transporter polypeptides (Oatp) rather than P-glycoprotein. Furthermore, sodium-potassium ATPase inhibition and incomplete oxygen-glucose deprivation (OGD, 20% O2) reduced fluorescein efflux, while complete OGD (0% O2) abolished efflux. We provide evidence for active efflux of fluorescein in vitro. Impaired efflux of fluorescein could thus contribute to the frequently observed BBB dysfunction in neuropathologies in addition to blood-to-brain leakage.

Low-intensity noise exposure takes an essential part in the mechanism of late-onset hereditary hearing loss caused by Abcc1 mutation

With the development of the social economy, we are exposed to increasing noise in our daily lives. Our previous work found an ABCC1(NM_004996.3:c.A1769G, NP_004987.2:p.N590S) variant which cosegregated with the patients in an autosomal dominant non-syndromic hearing loss family. At present, the specific mechanism of deafness caused by ABCC1 mutation is still not clear. Using the knock-in mouse model simulating human ABCC1 mutation, we found that the occurrence of family-related phenotypes was likely attributed to the combination of the mouse genotype and low-intensity noise. GSH and GSSG are important physiological substrates of ABCC1. The destruction of GSH-GSSG balance in the cochleae of both Abcc1N591S/+ mice and Abcc1N591S/N591S mice during low-intensity noise exposure may result in irreversible damage to the hair cells of the cochleae, consequently leading to hearing loss in mice. The findings offered a potential novel idea for the prevention and management of hereditary hearing loss within this family.

Computer-aided pattern scoring (C@PS): a novel cheminformatic workflow to predict ligands with rare modes-of-action

The identification, establishment, and exploration of potential pharmacological drug targets are major steps of the drug development pipeline. Target validation requires diverse chemical tools that come with a spectrum of functionality, e.g., inhibitors, activators, and other modulators. Particularly tools with rare modes-of-action allow for a proper kinetic and functional characterization of the targets-of-interest (e.g., channels, enzymes, receptors, or transporters). Despite, functional innovation is a prime criterion for patentability and commercial exploitation, which may lead to therapeutic benefit. Unfortunately, data on new, and thus, undruggable or barely druggable targets are scarce and mostly available for mainstream modes-of-action only (e.g., inhibition). Here we present a novel cheminformatic workflow-computer-aided pattern scoring (C@PS)-which was specifically designed to project its prediction capabilities into an uncharted domain of applicability.

Characterization of a deazaflavin analog as a potent inhibitor of multidrug resistance-associated protein 1

Selective inhibition of overexpressed ATP binding cassette (ABC) transporters is an attractive approach to enhancing the efficacy of chemotherapeutics in multidrug resistant cancers. Previously, we reported that the cancer sensitizing effect of deazaflavin analogs, an important chemotype for developing combination treatments with topoisomerase II (TOP2) poisons, is associated with increased intracellular drug accumulation. Here we report the characterization of ZW-1226, a deazaflavin analog, as a potent inhibitor of multidrug resistance-associated protein 1 (MRP1). Specifically, ZW-1226 inhibited MRP1 with a 16-fold higher potency than the most widely used positive control MK-571 in vesicular transport assay and displayed excellent selectivity indices exceeding 100 over other major ABC transporters, including P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), MRP2 and MRP3. Mechanistically, we revealed that its MRP1 inhibitory action requires the participation of GSH. In chemo-sensitization test, ZW-1226 fully reversed the MRP1-mediated drug resistance to TOP2 poisons etoposide (ETP) and doxorubicin (DOX) in H69AR cells and conferred CC50s comparable to those in the sensitive parental NCI-H69 cells. The sensitization was associated with boosted intracellular accumulation of ETP and DOX and elevated endogenous GSH. Moreover, ZW-1226 showed potential to occupy the leukotriene C4 binding site in molecular docking with bovine MRP1, presumably with the help of GSH. Lastly, ZW-1226 exhibited high tissue to plasma partitions in mice but did not alter ETP distribution to normal tissues, suggesting it could be a viable lead with desirable pharmacokinetic properties to warrant further investigation.

Epigenetic modification of ferroptosis by non-coding RNAs in cancer drug resistance

The development of drug resistance remains a major challenge in cancer treatment. Ferroptosis, a unique type of regulated cell death, plays a pivotal role in inhibiting tumour growth, presenting new opportunities in treating chemotherapeutic resistance. Accumulating studies indicate that epigenetic modifications by non-coding RNAs (ncRNA) can determine cancer cell vulnerability to ferroptosis. In this review, we first summarize the role of chemotherapeutic resistance in cancer growth/development. Then, we summarize the core molecular mechanisms of ferroptosis, its upstream epigenetic regulation, and its downstream effects on chemotherapeutic resistance. Finally, we review recent advances in understanding how ncRNAs regulate ferroptosis and from such modulate chemotherapeutic resistance. This review aims to enhance general understanding of the ncRNA-mediated epigenetic regulatory mechanisms which modulate ferroptosis, highlighting the ncRNA-ferroptosis axis as a key druggable target in overcoming chemotherapeutic resistance.

ABCC1 Is a ΔNp63 Target Gene Overexpressed in Squamous Cell Carcinoma

The transcription factor ΔNp63 plays a pivotal role in maintaining the integrity of stratified epithelial tissues by regulating the expression of distinct target genes involved in lineage specification, cell stemness, cell proliferation and differentiation. Here, we identified the ABC transporter subfamily member ABCC1 as a novel ΔNp63 target gene. We found that in immortalized human keratinocytes and in squamous cell carcinoma (SCC) cells, ∆Np63 induces the expression of ABCC1 by physically occupying a p63-binding site (p63 BS) located in the first intron of the ABCC1 gene locus. In cutaneous SCC and during the activation of the keratinocyte differentiation program, ∆Np63 and ABCC1 levels are positively correlated raising the possibility that ABCC1 might be involved in the regulation of the proliferative/differentiative capabilities of squamous tissue. However, we did not find any gross alteration in the structure and morphology of the epidermis in humanized hABCC1 knock-out mice. Conversely, we found that the genetic ablation of ABCC1 led to a marked reduction in inflammation-mediated proliferation of keratinocytes, suggesting that ABCC1 might be involved in the regulation of keratinocyte proliferation upon inflammatory/proliferative signals. In line with these observations, we found a significant increase in ABCC1 expression in squamous cell carcinomas (SCCs), a tumor type characterized by keratinocyte hyper-proliferation and a pro-inflammatory tumor microenvironment. Collectively, these data uncover ABCC1 as an additional ∆Np63 target gene potentially involved in those skin diseases characterized by dysregulation of proliferation/differentiation balance.

ABCC1 deficiency potentiated noise-induced hearing loss in mice by impairing cochlear antioxidant capacity

The ABCC1 gene belongs to the ATP-binding cassette membrane transporter superfamily, which plays a crucial role in the efflux of various endogenous and exogenous substances. Mutations in ABCC1 can result in autosomal dominant hearing loss. However, the specific roles of ABCC1 in auditory function are not fully understood. Through immunofluorescence, we found that ABCC1 was expressed in microvascular endothelial cells (ECs) of the stria vascularis (StV) in the murine cochlea. Then, an Abcc1 knockout mouse model was established by using CRISPR/Cas9 technology to elucidate the role of ABCC1 in the inner ear. The ABR threshold did not significantly differ between WT and Abcc1-/- mice at any age studied. After noise exposure, the ABR thresholds of the WT and Abcc1-/- mice were significantly elevated. Interestingly, after 14 days of noise exposure, ABR thresholds largely returned to pre-exposure levels in WT mice but not in Abcc1-/- mice. Our subsequent experiments showed that microvascular integrity in the StV was compromised and that the number of outer hair cells and the number of ribbons were significantly decreased in the cochleae of Abcc1-/- mice post-exposure. Besides, the production of ROS and the accumulation of 4-HNE significantly increased. Furthermore, StV microvascular ECs were cultured to elucidate the role of ABCC1 in these cells under glucose oxidase challenge. Notably, 30 U/L glucose oxidase (GO) induced severe oxidative stress damage in Abcc1-/- cells. Compared with WT cells, the ROS and 4-HNE levels and the apoptotic rate were significantly elevated in Abcc1-/- cells. In addition, the reduced GSH/GSSG ratio was significantly decreased in Abcc1-/- cells after GO treatment. Taken together, Abcc1-/- mice are more susceptible to noise-induced hearing loss, possibly because ABCC1 knockdown compromises the GSH antioxidant system of StV ECs. The exogenous antioxidant N-acetylcysteine (NAC) may protect against oxidative damage in Abcc1-/- murine cochleae and ECs.

LINC00518: a key player in tumor progression and clinical outcomes

Long non-coding RNAs (lncRNAs), defined as RNA molecules exceeding 200 nucleotides in length, have been implicated in the regulation of various biological processes and the progression of tumors. Among them, LINC00518, a recently identified lncRNA encoded by a gene located on chromosome 6p24.3, consists of three exons and is predicted to positively regulate the expression of specific genes. LINC00518 has emerged as a key oncogenic lncRNA in multiple cancer types. It exerts its tumor-promoting effects by modulating the expression of several target genes, primarily through acting as a sponge for microRNAs (miRNAs). Additionally, LINC00518 influences critical signaling pathways, including the Wnt/β-catenin, JAK/STAT, and integrin β3/FAK pathways. Elevated levels of LINC00518 in tumor tissues are associated with increased tumor size, advanced clinical stage, metastasis, and poor survival prognosis. This review provides a comprehensive summary of the genetic characteristics, expression patterns, biological functions, and underlying mechanisms of LINC00518 in human diseases.

Vitamin B12 Metabolism: A Network of Multi-Protein Mediated Processes

The water-soluble vitamin, vitamin B12, also known as cobalamin, plays a crucial role in cellular metabolism, particularly in DNA synthesis, methylation, and mitochondrial functionality. Its deficiency can lead to hematological and neurological disorders; however, the manifestation of these clinical outcomes is relatively late. It leads to difficulties in the early diagnosis of vitamin B12 deficiency. A prolonged lack of vitamin B12 may have severe consequences including increased morbidity to neurological and cardiovascular diseases. Beyond inadequate dietary intake, vitamin B12 deficiency might be caused by insufficient bioavailability, blood transport disruptions, or impaired cellular uptake and metabolism. Despite nearly 70 years of knowledge since the isolation and characterization of this vitamin, there are still gaps in understanding its metabolic pathways. Thus, this review aims to compile current knowledge about the crucial proteins necessary to efficiently accumulate and process vitamin B12 in humans, presenting these systems as a multi-protein network. The epidemiological consequences, diagnosis, and treatment of vitamin B12 deficiency are also highlighted. We also discuss clinical warnings of vitamin B12 deficiency based on the ongoing test of specific moonlighting proteins engaged in vitamin B12 metabolic pathways.

Dissecting the pleiotropic roles of reactive oxygen species (ROS) in lung cancer: From carcinogenesis toward therapy

Lung cancer is a major cause of morbidity and mortality. The specific pulmonary structure to directly connect with ambient air makes it more susceptible to damage from airborne toxins. External oxidative stimuli and endogenous reactive oxygen species (ROS) play a crucial role in promoting lung carcinogenesis and development. The biological properties of higher ROS levels in tumor cells than in normal cells make them more sensitive and vulnerable to ROS injury. Therefore, the strategy of targeting ROS has been proposed for cancer therapy for decades. However, it is embarrassing that countless attempts at ROS-based therapies have had very limited success, and no FDA approval in the anticancer list was mechanistically based on ROS manipulation. Even compared with the untargetable proteins, such as transcription factors, ROS are more difficult to be targeted due to their chemical properties. Thus, the pleiotropic roles of ROS provide therapeutic potential for anticancer drug discovery, while a better dissection of the mechanistic action and signaling pathways is a prerequisite for future breakthroughs. This review discusses the critical roles of ROS in cancer carcinogenesis, ROS-inspired signaling pathways, and ROS-based treatment, exemplified by lung cancer. In particular, an eight considerations rule is proposed for ROS-targeting strategies and drug design and development.

ISTransbase: an online database for inhibitor and substrate of drug transporters

Drug transporters, integral membrane proteins found throughout the human body, play critical roles in physiological and biochemical processes through interactions with ligands, such as substrates and inhibitors. The extensive and disparate data on drug transporters complicate understanding their complex relationships with ligands. To address this challenge, it is essential to gather and summarize information on drug transporters, inhibitors and substrates, and simultaneously develop a comprehensive and user-friendly database. Current online resources often provide fragmented information and have limited coverage of drug transporter substrates and inhibitors, highlighting the need for a specialized, comprehensive and openly accessible database. ISTransbase addresses this gap by amassing a substantial amount of data from literature, government documents and open databases. It includes 16 528 inhibitors and 4465 substrates of 163 drug transporters from 18 different species, resulting in a total of 93 841 inhibitor records and 51 053 substrate records. ISTransbase provides detailed insights into drug transporters and their inhibitors/substrates, encompassing transporter and molecule structure, transporter function and distribution, as well as experimental methods and results from transport or inhibition experiments. Furthermore, ISTransbase offers three search strategies that allow users to retrieve drugs and transporters based on multiple selectable constraints, as well as perform checks for drug-drug interactions. Users can also browse and download data. In summary, ISTransbase (https://istransbase.scbdd.com/) serves as a valuable resource for accurately and efficiently accessing information on drug transporter inhibitors and substrates, aiding researchers in exploring drug transporter mechanisms and assisting clinicians in mitigating adverse drug reactions Database URL: https://istransbase.scbdd.com/.

Schiff bases and their metal complexes to target and overcome (multidrug) resistance in cancer

Overcoming multidrug resistance (MDR) is one of the major challenges in cancer therapy. In this respect, Schiff base-related compounds (bearing a R1R2CNR3 bond) gained high interest during the past decades. Schiff bases are considered privileged ligands for various reasons, including the easiness of their preparation and the possibility to form complexes with almost all transition metal ions. Schiff bases and their metal complexes exhibit many types of biological activities and are used for the treatment and diagnosis of various diseases. Until now, 13 Schiff bases have been investigated in clinical trials for cancer treatment and hypoxia imaging. This review represents the first collection of Schiff bases and their complexes which demonstrated MDR-reversal activity. The areas of drug resistance covered in this article involve: 1) Modulation of ABC transporter function, 2) Targeting lysosomal ABCB1 overexpression, 3) Circumvention of ABC transporter-mediated drug efflux by alternative routes of drug uptake, 4) Selective activity against MDR cancer models (collateral sensitivity), 5) Targeting GSH-detoxifying systems, 6) Overcoming apoptosis resistance by inducing necrosis and paraptosis, 7) Reactivation of mutated p53, 8) Restoration of sensitivity to DNA-damaging anticancer therapy, and 9) Overcoming drug resistance through modulation of the immune system. Through this approach, we would like to draw attention to Schiff bases and their metal complexes representing highly interesting anticancer drug candidates with the ability to overcome MDR.

Shikonin enhances chemosensitivity of oral cancer through β-catenin pathway

OBJECTIVES

This study concentrates on exploring the synergistic effect of shikonin on cisplatin against oral cancer.

METHODS

To analyze the IC50 value of shikonin, gradient concentrations of shikonin were added to the oral cancer cell culture medium. After the cisplatin-resistant cell line was established, the effects of cisplatin and shikonin on the survival rate, proliferation, apoptosis and related pathway protein expression of common/drug-resistant oral cancer cells were compared through MTT, clone formation, flow cytometry, and Western blot experiments. β-catenin, which had the most significant expression changes, was overexpressed and silenced, and used to design a reverse validation.

RESULTS

Shikonin inhibited the viability of oral cancer cells. Although cisplatin killed some cancer cells, its effect on drug-resistant cancer cells was significantly reduced. The addition of shikonin enhanced the sensitivity of drug-resistant cells to cisplatin. Shikonin regulated key proteins in cell proliferation and apoptosis-related pathways. Among them, shikonin generated the most evident inhibitory effect on β-catenin. Therefore, β-catenin overexpression plasmid/siβ-catenin was transfected into the cells. Silenced β-catenin was found to reinforce the damaging effect of cisplatin on cancer cells, and overexpressed β-catenin reversed the effect of shikonin.

CONCLUSION

By down-regulating β-catenin expression, shikonin improves the sensitivity of drug-resistant oral cancer cells to cisplatin.

Pan-cancer analysis of ABCC1 as a potential prognostic and immunological biomarker

ABCC1 belongs to the ATP-binding cassette (ABC) superfamily, which encompasses a total of 48 constituent members. ABCC1 has been shown to be associated with the growth, progression, and drug resistance of various types of cancer. However, the impact of ABCC1 on cancer immune infiltration and pan-cancer prognosis has been rarely studied. Our comprehensive pan-cancer analysis unveiled elevated ABCC1 expression across various cancers. ABCC1 overexpression consistently predicted unfavorable outcomes based on TCGA data. Moreover, ABCC1 expression exhibited intricate associations with diverse immune-related genes and demonstrated a close correlation with immune scores across multiple tumor types. Analysis of scRNA-seq data from the GEO database revealed that the expression of ABCC1 in hepatocellular carcinoma (HCC) cells is significant positively correlated with macrophage infiltration. Furthermore, various in vitro and in vivo experiments substantiated the role of ABCC1 in promoting the progression of HCC, along with increased macrophage recruitment. Based on the results, we propose ABCC1 as a potentially valuable prognostic indicator and a prospective target for immune-based cancer therapies.

Synergistic effects of multidrug/material combination deliver system for anti-mutidrug-resistant tumor

Multidrug resistance (MDR) is a public health issue of particular concern, for which nanotechnology-based multidrug delivery systems are considered among the most effective suppressive strategies for such resistance in tumors. However, for such strategies to be viable, the notable shortcomings of reduced loading efficiency and uncontrollable drug release ratio need to be addressed. To this end, we developed a novel "multidrug/material" co-delivery system, using d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS, P-gp efflux pump inhibitor) and poly(amidoamine) (PAMAM) to fabricate a precursor material with the properties of reversing MDR and having a long-cycle. Further, to facilitate multidrug co-delivery, we loaded doxorubicin(Dox) and curcumin(Cur, cardiotoxicity modifier and P-gp inhibitor) into PAMAM-TPGS nano-micelles respectively, and mixed in appropriate proportions. The multidrug/material co-delivery system thus obtained was characterized by high drug loading and a controllable drug release ratio in the physiological environment. More importantly, in vitro and in vivo pharmacodynamic studies indicated that the multidrug/material co-delivery system facilitated the reversal of MDR. Moreover, the system has increased anti-tumor activity and is biologically safe. We accordingly propose that the "multidrug/material" co-delivery system developed in this study could serve as a potential platform for reversing MDR and achieving safe and effective clinical treatment.

The functions and mechanisms of post-translational modification in protein regulators of RNA methylation: Current status and future perspectives

RNA methylation, an epigenetic modification that does not alter gene sequence, may be important to diverse biological processes. Protein regulators of RNA methylation include "writers," "erasers," and "readers," which respectively deposit, remove, and recognize methylated RNA. RNA methylation, particularly N6-methyladenosine (m6A), 5-methylcytosine (m5C), N3-methylcytosine (m3C), N1-methyladenosine (m1A) and N7-methylguanosine (m7G), has been suggested as disease therapeutic targets. Despite advances in the structure and pharmacology of RNA methylation regulators that have improved drug discovery, regulating these proteins by various post-translational modifications (PTMs) has received little attention. PTM modifies protein structure and function, affecting all aspects of normal biology and pathogenesis, including immunology, cell differentiation, DNA damage repair, and tumors. It is becoming evident that RNA methylation regulators are also regulated by diverse PTMs. PTM of RNA methylation regulators induces their covalent linkage to new functional groups, hence modifying their activity and function. Mass spectrometry has identified many PTMs on protein regulators of RNA methylation. In this review, we describe the functions and PTM of protein regulators of RNA methylation and summarize the recent advances in the regulatory mode of human disease and its underlying mechanisms.

Advances in the structure, mechanism and targeting of chemoresistance-linked ABC transporters

Cancer cells frequently display intrinsic or acquired resistance to chemically diverse anticancer drugs, limiting therapeutic success. Among the main mechanisms of this multidrug resistance is the overexpression of ATP-binding cassette (ABC) transporters that mediate drug efflux, and, specifically, ABCB1, ABCG2 and ABCC1 are known to cause cancer chemoresistance. High-resolution structures, biophysical and in silico studies have led to tremendous progress in understanding the mechanism of drug transport by these ABC transporters, and several promising therapies, including irradiation-based immune and thermal therapies, and nanomedicine have been used to overcome ABC transporter-mediated cancer chemoresistance. In this Review, we highlight the progress achieved in the past 5 years on the three transporters, ABCB1, ABCG2 and ABCC1, that are known to be of clinical importance. We address the molecular basis of their broad substrate specificity gleaned from structural information and discuss novel approaches to block the function of ABC transporters. Furthermore, genetic modification of ABC transporters by CRISPR-Cas9 and approaches to re-engineer amino acid sequences to change the direction of transport from efflux to import are briefly discussed. We suggest that current information regarding the structure, mechanism and regulation of ABC transporters should be used in clinical trials to improve the efficiency of chemotherapeutics for patients with cancer.

Tumor microenvironment diversity and plasticity in cancer multidrug resistance

Multidrug resistance (MDR) poses a significant obstacle to effective cancer treatment, and the tumor microenvironment (TME) is crucial for MDR development and reversal. The TME plays an active role in promoting MDR through several pathways. However, a promising therapeutic approach for battling MDR involves targeting specific elements within the TME. Therefore, this comprehensive review elaborates on the research developments regarding the dual role of the TME in promoting and reversing MDR in cancer. Understanding the complex role of the TME in promoting and reversing MDR is essential to developing effective cancer therapies. Utilizing the adaptability of the TME by targeting novel TME-specific factors, utilizing combination therapies, and employing innovative treatment strategies can potentially combat MDR and achieve personalized treatment outcomes for patients with cancer.

Crosstalk between endoplasmic reticulum stress and multidrug-resistant cancers: hope or frustration

Endoplasmic reticulum stress (ERS) is a kind of cell response for coping with hypoxia and other stresses. Pieces of evidence show that continuous stress can promote the occurrence, development, and drug resistance of tumors through the unfolded protein response. Therefore, the abnormal ac-tivation of ERS and its downstream signaling pathways not only can regulate tumor growth and metastasis but also profoundly affect the efficacy of antitumor therapy. Therefore, revealing the molecular mechanism of ERS may be expected to solve the problem of tumor multidrug resistance (MDR) and become a novel strategy for the treatment of refractory and recurrent tumors. This re-view summarized the mechanism of ERS and tumor MDR, reviewed the relationship between ERS and tumor MDR, introduced the research status of tumor tissue and ERS, and previewed the prospect of targeting ERS to improve the therapeutic effect of tumor MDR. This article aims to provide researchers and clinicians with new ideas and inspiration for basic antitumor treatment.

Drug resistance and new therapies in gallbladder cancer

Gallbladder cancer (GBC) is a highly aggressive malignancy, which poses significant challenges for timely diagnosis, resulting in a dismal prognosis. Chemotherapy serves as a primary treatment option in cases where surgery is not feasible. However, the emergence of chemoresistance poses a significant challenge to the effectiveness of chemotherapy, ultimately resulting in a poor prognosis. Despite extensive research on mechanisms of chemotherapeutic resistance in oncology, the underlying mechanisms of chemoresistance in GBC remain poorly understood. In this review, we present the findings from the last decade on the molecular mechanisms of chemotherapeutic resistance in GBC. We hope that these insights may provide novel therapeutic and experimental targets for further investigations into this lethal disease.

Cellular and Molecular Mechanisms of the Tumor Stroma in Colorectal Cancer: Insights into Disease Progression and Therapeutic Targets

Colorectal cancer (CRC) is a major health burden worldwide and is the third most common type of cancer. The early detection and diagnosis of CRC is critical to improve patient outcomes. This review explores the intricate interplay between the tumor microenvironment, stromal interactions, and the progression and metastasis of colorectal cancer. The review begins by assessing the gut microbiome's influence on CRC development, emphasizing its association with gut-associated lymphoid tissue (GALT). The role of the Wnt signaling pathway in CRC tumor stroma is scrutinized, elucidating its impact on disease progression. Tumor budding, its effect on tumor stroma, and the implications for patient prognosis are investigated. The review also identifies conserved oncogenic signatures (COS) within CRC stroma and explores their potential as therapeutic targets. Lastly, the seed and soil hypothesis is employed to contextualize metastasis, accentuating the significance of both tumor cells and the surrounding stroma in metastatic propensity. This review highlights the intricate interdependence between CRC cells and their microenvironment, providing valuable insights into prospective therapeutic approaches targeting tumor-stroma interactions.

FACS-based genome-wide CRISPR screens define key regulators of DNA damage signaling pathways

DNA damage-activated signaling pathways are critical for coordinating multiple cellular processes, which must be tightly regulated to maintain genome stability. To provide a comprehensive and unbiased perspective of DNA damage response (DDR) signaling pathways, we performed 30 fluorescence-activated cell sorting (FACS)-based genome-wide CRISPR screens in human cell lines with antibodies recognizing distinct endogenous DNA damage signaling proteins to identify critical regulators involved in DDR. We discovered that proteasome-mediated processing is an early and prerequisite event for cells to trigger camptothecin- and etoposide-induced DDR signaling. Furthermore, we identified PRMT1 and PRMT5 as modulators that regulate ATM protein level. Moreover, we discovered that GNB1L is a key regulator of DDR signaling via its role as a co-chaperone specifically regulating PIKK proteins. Collectively, these screens offer a rich resource for further investigation of DDR, which may provide insight into strategies of targeting these DDR pathways to improve therapeutic outcomes.

Ferroptosis: a novel regulated cell death participating in cellular stress response, radiotherapy, and immunotherapy

BACKGROUND

Ferroptosis is a regulated cell death mode triggered by iron-dependent toxic membrane lipid peroxidation. As a novel cell death modality that is morphologically and mechanistically different from other forms of cell death, such as apoptosis and necrosis, ferroptosis has attracted extensive attention due to its association with various diseases. Evidence on ferroptosis as a potential therapeutic strategy has accumulated with the rapid growth of research on targeting ferroptosis for tumor suppression in recent years.

METHODS

We summarize the currently known characteristics and major regulatory mechanisms of ferroptosis and present the role of ferroptosis in cellular stress responses, including ER stress and autophagy. Furthermore, we elucidate the potential applications of ferroptosis in radiotherapy and immunotherapy, which will be beneficial in exploring new strategies for clinical tumor treatment.

RESULT AND CONCLUSION

Based on specific biomarkers and precise patient-specific assessment, targeting ferroptosis has great potential to be translated into practical new approaches for clinical cancer therapy, significantly contributing to the prevention, diagnosis, prognosis, and treatment of cancer.

Synthesis of structural analogues of Reversan by ester aminolysis: an access to pyrazolo[1,5-a]pyrimidines from chalcones

Reversan, a multidrug resistance-associated protein (MRP1) inhibitor described more than a decade ago, is a commercial drug (CAS: 313397-13-6) that has a high price and is six to eight times more potent than known drug transporter inhibitors. However, to date, a complete route for synthesizing pyrazolo[1,5-a]pyrimidine-based Reversan is yet to be published. Herein, the silica gel-mediated synthesis of Reversan and a novel family of its structural analogues (amides) via the microwave-assisted amidation reaction of 3-carboethoxy-5,7-diphenylpyrazolo[1,5-a]pyrimidine (ester) with primary amines is reported. Moreover, a set of this ester-type precursor was obtained using the NaF/alumina-mediated reaction of 5-amino-3-carboethoxy-1H-pyrazole with chalcones, implying a final removal of H₂ using Na₂S₂O₈. Both esters and amides were obtained in high yields using heterogeneous catalyst and solvent-free, highly efficient, and scalable synthetic protocols.

Sulforaphane Inhibits Foam Cell Formation and Atherosclerosis via Mechanisms Involving the Modulation of Macrophage Cholesterol Transport and the Related Phenotype

Sulforaphane (SFN), an isothiocyanate, is one of the major dietary phytochemicals found in cruciferous vegetables. Many studies suggest that SFN can protect against cancer and cardiometabolic diseases. Despite the proposed systemic and local vascular protective mechanisms, SFN's potential to inhibit atherogenesis by targeting macrophages remains unknown. In this study, in high fat diet fed ApoE-deficient (ApoE^-/-) mice, oral SFN treatment improved dyslipidemia and inhibited atherosclerotic plaque formation and the unstable phenotype, as demonstrated by reductions in the lesion areas in both the aortic sinus and whole aorta, percentages of necrotic cores, vascular macrophage infiltration and reactive oxygen species (ROS) generation. In THP-1-derived macrophages, preadministration SFN alleviated oxidized low-density lipoprotein (ox-LDL)-induced lipid accumulation, oxidative stress and mitochondrial injury. Moreover, a functional study revealed that peritoneal macrophages isolated from SFN-treated mice exhibited attenuated cholesterol influx and enhanced apolipoprotein A-I (apoA-I)- and high-density lipoprotein (HDL)-mediated cholesterol efflux. Mechanistic analysis revealed that SFN supplementation induced both intralesional and intraperitoneal macrophage phenotypic switching toward high expression of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1) and ATP-binding cassette subfamily A/G member 1 (ABCA1/G1) and low expression of peroxisome proliferator-activated receptor γ (PPARγ) and cluster of differentiation 36 (CD36), which was further validated by the aortic protein expression. These results suggest that the regulation of macrophages' cholesterol transport and accumulation may be mainly responsible for SFN's potential atheroprotective properties, and the regulatory mechanisms might involve upregulating ABCA1/G1 and downregulating CD36 via the modulation of PPARγ and Nrf2.

An orthogonally activatable CRISPR-Cas13d nanoprodrug to reverse chemoresistance for enhanced chemo-photodynamic therapy

Orthogonal therapy that combines CRISPR-based gene editing and prodrug-based chemotherapy is a promising approach to combat multidrug-resistant cancer. However, its potency to precisely regulate different therapeutic modalities in vivo is limited due to the lack of an integrated platform with high spatiotemporal resolution. Taking advantage of CRISPR technology, a Pt(iv)-based prodrug and orthogonal emissive upconversion nanoparticles (UCNPs), we herein rationally designed the first logic-gated CRISPR-Cas13d-based nanoprodrug for orthogonal photomodulation of gene editing and prodrug release for enhanced cancer therapy. The nanoprodrug (URL) was constructed by encapsulating a green light-activatable Pt(iv) prodrug and UV light-activatable Cas13d gene editing tool into UCNPs. We demonstrated that URL maintained excellent orthogonal emission behaviors under 808 and 980 nm excitations, allowing wavelength-selective photoactivation of Cas13d and the prodrug for downregulation of the resistance-related gene and induction of chemo-photodynamic therapy, respectively. Moreover, the photomodulation superiority of URL for overcoming drug resistance was highlighted by integrating it with a Boolean logic gate for programmable modulation of multiple cell behaviors. Importantly, in vivo studies demonstrated that URL can promote Pt(iv) prodrug activation and ROS generation and massively induce on-target drug accumulation by Cas13d-mediated drug resistance attenuation, delivering an ultimate chemo-photodynamic therapeutic performance in efficiently eradicating primary tumors and preventing further liver metastasis. Collectively, our results suggest that URL expands the Cas13d-based genome editing toolbox into prodrug nanomedicine and accelerates the discovery of new orthogonal therapeutic approaches.

ABCB1 and ABCC1 Function during TGF-β-Induced Epithelial-Mesenchymal Transition: Relationship between Multidrug Resistance and Tumor Progression

Multidrug resistance (MDR) and induction of metastasis are some of the puzzles encountered during cancer chemotherapy. The MDR phenotype is associated with overexpression of ABC transporters, involved in drug efflux. Metastasis originates from the epithelial-mesenchymal transition (EMT), in which cells acquire a migratory phenotype, invading new tissues. ABC transporters' role during EMT is still elusive, though cells undergoing EMT exhibit enhanced ABCB1 expression. We demonstrated increased ABCB1 expression but no change in activity after TGF-β-induced EMT in A549 cells. Moreover, ABCB1 inhibition by verapamil increased snail and fibronectin expression, an event associated with upregulation of ABCB1, evidencing coincident cell signaling pathways leading to ABCB1 and EMT-related markers transcription, rather than a direct effect of transport. Additionally, for the first time, increased ABCC1 expression and activity was observed after EMT, and use of ABCC1 inhibitors partially inhibited EMT-marker snail, although increased ABCC1 function translated into collateral sensibility to daunorubicin. More investigations must be done to evaluate the real benefits that the gain of ABC transporters might have on the process of metastasis. Considering ABCC1 is involved in the stress response, affecting intracellular GSH content and drug detoxification, this transporter could be used as a therapeutic target in cancer cells undergoing EMT.

Dual-drug codelivery nanosystems: An emerging approach for overcoming cancer multidrug resistance

Multidrug resistance (MDR) promotes tumor recurrence and metastasis and heavily reduces anticancer efficiency, which has become a primary reason for the failure of clinical chemotherapy. The mechanisms of MDR are so complex that conventional chemotherapy usually fails to achieve an ideal therapeutic effect and even accelerates the occurrence of MDR. In contrast, the combination of chemotherapy with dual-drug has significant advantages in tumor therapy. A novel dual-drug codelivery nanosystem, which combines dual-drug administration with nanotechnology, can overcome the application limitation of free drugs. Both the characteristics of nanoparticles and the synergistic effect of dual drugs contribute to circumventing various drug-resistant mechanisms in tumor cells. Therefore, developing dual-drug codelivery nanosystems with different multidrug-resistant mechanisms has an important reference value for reversing MDR and enhancing the clinical antitumor effect. In this review, the advantages, principles, and common codelivery nanocarriers in the application of dual-drug codelivery systems are summarized. The molecular mechanisms of MDR and the dual-drug codelivery nanosystems designed based on different mechanisms are mainly introduced. Meanwhile, the development prospects and challenges of codelivery nanosystems are also discussed, which provide guidelines to exploit optimized combined chemotherapy strategies in the future.

A hyaluronic acid modified cuprous metal-organic complex for reversing multidrug resistance via redox dyshomeostasis

Multidrug resistance (MDR) which is often related to the overexpression of P-glycoprotein (P-gp) in drug-resistant cancer cells has been a major problem faced by current cancer chemotherapy. Reversing P-gp-related MDR by disrupting tumor redox homeostasis that regulates the expression of P-gp is a promising strategy. In this work, a hyaluronic acid (HA) modified nanoscale cuprous metal-organic complex (HA-CuTT) was developed to reverse P-gp-related MDR via two-way regulated redox dyshomeostasis, which was achieved by both Cu⁺-catalyzed generation of •OH and disulfide bonds-mediated depletion of glutathione (GSH). In vitro studies reveal that the DOX-loaded complex (HA-CuTT@DOX) has excellent targeting ability to HepG2-ADR cells due to the modification of HA and effectively induces redox dyshomeostasis in HepG2-ADR cells. Moreover, HA-CuTT@DOX can cause mitochondrial damage, decrease ATP level, and downregulate the P-gp expression, thereby leading to the reversal of MDR and the increased drug accumulation in HepG2-ADR cells. Importantly, in vivo experimental results show that it can achieve effective inhibition (89.6 %) of tumor growth in nude mice bearing HepG2-ADR cells. This is the first work to reverse P-gp-related MDR via two-way regulated redox dyshomeostasis based on a HA modified nanoscale cuprous metal-organic complex, providing a new therapeutic paradigm for effective treatment of MDR-related cancer.

Design, Synthesis, and Biological Evaluation of Novel Amyl Ester Tethered Dihydroartemisinin-Isatin Hybrids as Potent Anti-Breast Cancer Agents

A series of novel amyl ester tethered dihydroartemisinin-isatin hybrids 4a-d and 5a-h were designed, synthesized, and evaluated as anti-breast cancer agents. The synthesized hybrids were preliminarily screened against estrogen receptor-positive (MCF-7 and MCF-7/ADR) and triple-negative (MDA-MB-231 and) breast cancer cell lines. Three hybrids 4a,d and 5e not only were more potent than artemisinin and adriamycin against drug-resistant MCF-7/ADR and MDA-MB-231/ADR breast cancer cell lines, but also displayed non-cytotoxicity towards normal MCF-10 A breast cells, and the SI values were >4.15, indicating their excellent selectivity and safety profiles. Thus, hybrids 4a,d and 5e could act as potential anti-breast cancer candidates and were worthy of further preclinical evaluations. Moreover, the structure-activity relationships which may facilitate further rational design of more effective candidates were also enriched.

Modular Biomimetic Strategy Enabled Discovery of Simplified Pseudo-Natural Macrocyclic P-Glycoprotein Inhibitors Capable of Overcoming Multidrug Resistance

Natural macrocycles have shown impressive activity to overcome P-glycoprotein (P-gp)-mediated multidrug resistance (MDR). However, the total synthesis and structural modification of natural macrocycles are challenging, which would hamper the deeper investigations of their structure-activity relationship (SAR) and drug likeness. Herein, we describe a modular biomimetic strategy to expeditiously achieve a new class of macrocycles featuring polysubstituted 1,3-diene, which efficiently inhibited P-gp and reversed MDR in cancer cells. The SAR analysis revealed that the size and linker of the macrocycles are important structural characteristics to restore activity. Particularly, 32 containing a naphthyl group and (d)-Phe moiety has higher potency with an excellent reversal fold than verapamil at a concentration of 5 μM, which induces conformational change of P-gp and inhibits its function instead of altering P-gp expression. Furthermore, 23 and 32 were identified to be attractive leads, which possess a good pharmacokinetic profile and antitumor activity in a KBV200 xenograft mouse model.

The synergistic effects of PRDX5 and Nrf2 on lung cancer progression and drug resistance under oxidative stress in the zebrafish models

Previous studies have shown that PRDX5 and Nrf2 are antioxidant proteins related to abnormal reactive oxidative species (ROS). PRDX5 and Nrf2 play a critical role in the progression of inflammations and tumors. The combination of PRDX5 and Nrf2 was examined by Co-immunoprecipitation, western blotting and Immunohistochemistry. H2O2 was applied to affect the production of ROS and induced multi-resistant protein 1 (MRP1) expression in NSCLC cells. The zebrafish models mainly investigated the synergistic effects of PRDX5 and Nrf2 on lung cancer drug resistance under oxidative stress. We showed that PRDX5 and Nrf2 form a complex and significantly increase the NSCLC tissues compared to adjacent tissues. The oxidative stress improved the combination of PRDX5 and Nrf2. We demonstrated that the synergy between PRDX5 and Nrf2 is positively related to the proliferation and drug resistance of NSCLC cells in the zebrafish models. In conclusion, our data indicated that PRDX5 could bind to Nrf2 and has a synergistic effect with Nrf2. Meanwhile, in the zebrafish models, PRDX5 and Nrf2 have significant regulatory impacts on lung cancer progression and drug resistance activities under oxidative stress.

Carbon Dots-Based Nanozyme for Drug-Resistant Lung Cancer Therapy by Encapsulated Doxorubicin/siRNA Cocktail

Background

Nanomaterials exhibited intrinsic enzyme-like properties due to the unique properties compared with natural enzyme. Carbon dots (CDs) are an important kind of quantum-sized nanomaterials, which have enormous application potential in bio-imaging, drug carrier, and nanosystems. Carbon dots possess intrinsic enzyme-like properties, such as glutathione (GSH) oxidase or peroxidase activities.

Methods

A co-delivery nanosystem that could carry siRNA and doxorubucin (DOX) simultaneously has been studied in this work. The co-delivery based on carbon dots was surface-modified with poly-ethylenimine (PEI) and loaded the siMRP1 with chemotherapeutics on the surface with pH-triggered drug release. The CD-PEI was synthesized by one-step microwave assisted method; the PEI was raw materials and passivator during the reaction process that makes CDs exhibit excellent optical property.

Results

The CD-PEI was capable of loading and delivering siMRP1 and DOX to tumors and releasing them synchronously in cells in an acid-triggered manner. The particles exhibited GSH oxidase-like catalytic property, oxidizing GSH to oxidized glutathione with concomitant increase of reactive oxygen species (ROS). We found that silencing of MRP1 by co-delivery system antagonized chemoresistance by increasing DOX accumulation and significantly enhancing the inhibitory effect of cell viability induced by CD-PEI-DOX. The co-delivery system dramatically inhibited tumor growth in xenograft model, and CDs counteracted MRP1 function by siRNA-mediated knockdown of MRP1.

Conclusion

Taken together, we uncover the potential role of CDs with a combination of siRNA and chemotherapeutics in overcoming chemoresistance of lung cancer by suppressing MRP1 and oxidation of GSH. Our findings imply its potential of antagonizing chemoresistance to enhance therapeutic efficiency of doxorubicin in clinical practices of lung cancer treatment.

Small molecule inhibitors targeting the cancers

Compared with traditional therapies, targeted therapy has merits in selectivity, efficacy, and tolerability. Small molecule inhibitors are one of the primary targeted therapies for cancer. Due to their advantages in a wide range of targets, convenient medication, and the ability to penetrate into the central nervous system, many efforts have been devoted to developing more small molecule inhibitors. To date, 88 small molecule inhibitors have been approved by the United States Food and Drug Administration to treat cancers. Despite remarkable progress, small molecule inhibitors in cancer treatment still face many obstacles, such as low response rate, short duration of response, toxicity, biomarkers, and resistance. To better promote the development of small molecule inhibitors targeting cancers, we comprehensively reviewed small molecule inhibitors involved in all the approved agents and pivotal drug candidates in clinical trials arranged by the signaling pathways and the classification of small molecule inhibitors. We discussed lessons learned from the development of these agents, the proper strategies to overcome resistance arising from different mechanisms, and combination therapies concerned with small molecule inhibitors. Through our review, we hoped to provide insights and perspectives for the research and development of small molecule inhibitors in cancer treatment.

Construction and validation of a novel Ferroptosis-related gene signature predictive model in rectal Cancer

Background

Rectal cancer (RC) is one of the most common malignant tumors. Ferroptosis is an iron-dependent form of cell death, which plays an important role in various cancers. However, the correlation between ferroptosis-related genes (FRGs) and prognosis in RC remains unclear.

Methods

Gene expression data from The Cancer Genome Atlas Rectum adenocarcinoma (TCGA-READ) and GSE87211 were downloaded. Clustering and functional enrichment were evaluated. A FRGs risk score was established based on the univariate Cox analysis and the Least absolute shrinkage and selection operator (LASSO) analysis. K-M analysis and ROC analysis were conducted to determine prognostic values. qRT-PCR was performed to validate levels of mRNA expression. Multivariate Cox analysis was used to build a prognostic prediction model based on the risk score.

Results

Based on FRGs, RC patients were grouped into two clusters. In the functional enrichment of differentially expressed genes between the two clusters, immune-related pathways dominated. A novel FRGs signature with 14 genes related to the overall survival (OS) of RC was established. qRT-PCR of the 14 genes identified TP63, ISCU, PLIN4, MAP3K5, OXSR, FANCD2 and ATM were overexpressed in RC tissue; HSPB1, MAPK1, ABCC1, PANX1, MAPK9 and ATG7 were underexpressed; TUBE1 had no difference. The high-risk group had a significantly lower OS than the low-risk group (P < 0.001), and ROC curve analysis confirmed the signature’s predictive capacity. Multivariate analysis demonstrated that the risk score and age were independent prognostic factors.

Conclusion

A novel FRGs model can be used to predict the prognosis in RC, as well as to guide individual treatment.