Development Of Drug Resistance Research Articles

The small non-coding RNA Vaultrc5 is dispensable to mouse development.

Vault RNAs (vtRNAs) are evolutionarily conserved small non-coding RNAs transcribed by RNA polymerase lll. Vault RNAs were initially described as components of the vault particle, but have since been assigned multiple vault-independent functions including regulation of PKR activity, apoptosis, autophagy, lysosome biogenesis, and viral particle trafficking. The full-length transcript has also been described as noncanonical source of miRNAs which are processed in a DICER-dependent manner. As central molecules in vault-dependent and independent processes, vtRNAs have been attributed numerous biological roles including regulation of cell proliferation and survival, response to viral infections, drug resistance, and animal development. Yet, their impact to mammalian physiology remains largely unexplored. To study vault RNAs in vivo, we generated a mouse line with a conditional Vaultrc5 loss of function allele. Because Vaultrc5 is the sole murine vtRNA, this allele enables the characterization of the physiological requirements of this conserved class of small regulatory RNAs in mammals. Using this strain, we show that mice constitutively null for Vaultrc5 are viable and histologically normal but have a slight reduction in platelet counts pointing to a potential role for vtRNAs in hematopoiesis. This work paves the way for further in vivo characterizations of this abundant but mysterious RNA molecule. Specifically, it enables the study of the biological consequences of constitutive or lineage-specific Vaultrc5 deletion and of the physiological requirements for an intact Vaultrc5 during normal hematopoiesis or in response to cellular stresses such as oncogene expression, viral infection, or drug treatment.

Synthesis, structural modification, and biological activity of a novel bisindole alkaloid iheyamine A

Diseases caused by plant viruses and pathogens pose a serious threat to crop yield and quality. Traditional pesticides have gradually developed drug resistance and brought certain environmental safety issues during long-term overuse. There is an urgent need to discover new candidate compounds to address these issues. In this study, we achieved the efficient synthesis of iheyamine A and its derivatives, and discovered their excellent antiviral activities against tobacco mosaic virus (TMV). Most compounds displayed higher antiviral activities against TMV than commercial ribavirin at 500 μg/mL, with compounds 3a (Inactive effect IC50: 162 µg/mL), 3d (Inactive effect IC50: 249 µg/mL), 6p (Inactive effect IC50: 254 µg/mL), and 7a (Inactive effect IC50: 234 µg/mL) exhibiting better antiviral activities than ningnanmycin at 500 μg/mL (Inactive effect IC50: 269 µg/mL). Meanwhile, the structure–activity relationships of this type of compounds were systematically studied. We chose 3a for further antiviral mechanism research and found that it can directly act on viral coat protein (CP). The interaction of 3a and CP was further verified via molecular docking. These compounds also showed broad-spectrum fungicidal activities against 8 plant pathogenic fungi, especially for P. piricola. This study provides a reference for the role of iheyamine alkaloids in combating plant pathogenic diseases.

Recombinant Methioninase Increases Eribulin Efficacy 16-fold in Highly Eribulin-resistant HT1080 Fibrosarcoma Cells, Demonstrating Potential to Overcome the Clinical Challenge of Drug-resistant Soft-tissue Sarcoma.

A major challenge in treating soft-tissue sarcoma is the development of drug resistance. Eribulin, an anti-tubulin agent, is used as a second-line chemotherapy for patients with unresectable or metastatic soft-tissue sarcoma. However, most patients with advanced soft-tissue sarcoma are resistant to eribulin and do not survive. Recombinant methioninase (rMETase) targets the fundamental and general hallmark of cancer, methionine addiction, termed the Hoffman Effect. The present study aimed to show how much rMETase could increase the efficacy of eribulin on eribulin-resistant fibrosarcoma cells in vitro. HT1080 human fibrosarcoma cells were exposed to step-wise increasing concentrations of eribulin from 0.15-0.4 nM to establish eribulin-resistant HT1080 (ER-HT1080). ER-HT1080 cells were cultured in vitro and divided into four groups: untreated control; eribulin treated (0.15 nM); rMETase treated (0.75 U/ml); and eribulin (0.15 nM) plus rMETase (0.75 U/ml) treated. The IC50 of eribulin on ER-HT1080 cells was 0.95 nM compared to the IC50 of 0.15 nM on HT1080 cells, a 6-fold increase. The IC50 of rMETase on ER-HT1080 and HT1080 was 0.87 U/ml and 0.75 U/ml, respectively. The combination of rMETase (0.75 U/ml) and eribulin (0.15 nM) was synergistic on ER-HT1080 cells resulting in an inhibition of 80.1% compared to eribulin alone (5.0%) or rMETase alone (47.1%) (p<0.05). rMETase thus increased the efficacy of eribulin 16-fold on eribulin-resistant fibrosarcoma cells. The present study showed that the combination of eribulin and rMETase can overcome high eribulin resistance of fibrosarcoma. The present results demonstrate that combining rMETase with first- or second-line therapy for soft-tissue sarcoma has the potential to overcome the intractable clinical problem of drug-resistant soft-tissue sarcoma.

Marine Bacteriocins: An Evolutionary Gold Mine to Payoff Antibiotic Resistance

The rapid evolution of drug resistance is one of the greatest health issues of the 21st century. There is an alarming situation to find new therapeutic strategies or candidate drugs to tackle ongoing multi-drug resistance development. The marine environment is one of the prime natural ecosystems on Earth, the majority of which is still unexplored, especially when it comes to the microbes. A wide variety of bioactive compounds have been obtained from a varied range of marine organisms; however, marine bacteria-produced bacteriocins are still undermined. Owing to the distinct environmental stresses that marine bacterial communities encounter, their bioactive compounds frequently undergo distinct adaptations that confer on them a variety of shapes and functions, setting them apart from their terrestrial counterparts. Bacterially produced ribosomally synthesized and posttranslationally modified peptides (RiPPs), known as bacteriocins, are one of the special interests to be considered as an alternative to conventional antibiotics because of their variety in structure and diverse potential biological activities. Additionally, the gut microbiome of marine creatures are a largely unexplored source of new bacteriocins with promising activities. There is a huge possibility of novel bacteriocins from marine bacterial communities that might come out as efficient candidates to fight against antibiotic resistance, especially in light of the growing pressure from antibiotic-resistant diseases and industrial desire for innovative treatments. The present review summarizes known and fully characterized marine bacteriocins, their evolutionary aspects, challenges, and the huge possibilities of unexplored novel bacteriocins from marine bacterial communities present in diverse marine ecosystems.

HerpesDRG: a comprehensive resource for human herpesvirus antiviral drug resistance genotyping

The prevention and treatment of many herpesvirus associated diseases is based on the utilization of antiviral therapies, however therapeutic success is limited by the development of drug resistance. Currently no single database cataloguing resistance mutations exists, which hampers the use of sequence data for patient management. We therefore developed HerpesDRG, a drug resistance mutation database that incorporates all the known resistance genes and current treatment options, built from a systematic review of available genotype to phenotype literature. The database is released along with an R package that provides a simple approach to resistance variant annotation and clinical implication analysis from common sanger and next generation sequencing data. This represents the first openly available and community maintainable database of drug resistance mutations for the human herpesviruses (HHV), developed for the community of researchers and clinicians tackling HHV drug resistance.

Immunologic, virologic and drug resistance outcomes in an HIV-infected prospective cohort on treatment in South Africa.

In September 2016, South Africa introduced the Universal Test and Treat (UTT) programme to manage HIV infection. However, the development of drug resistance and sustaining viral suppression are challenges to the success of treatment programmes. This prospective observational study describes virologic, immunologic, and drug resistance profiles in a test and treat cohort in north-eastern South Africa. Five hundred and thirty-four HIV-1 positive antiretroviral naïve adults entering treatment programmes were enrolled between January 2016 and February 2018. Trends in CD4+ cell count, viral load, and drug resistance by examination of deep sequences were assessed at baseline and every three months, for 24 months. Seventy-five percent were late initiators into ART (that is baseline CD4+ cell counts < 500 cells/microliter) and 16% were early initiators into ART and baseline CD4 was not available for 9%. Eleven percent (12/104) achieved immunological response after 6 months, 39.4% (41 /104) after 12 months, and 97.5% (101/104) after 24 months. Seventy-one percent (381/534) had baseline viral loads >1000 RNA copies/ml. Nine percent (22/246) achieved viral suppression after 3 months, 50% (122/246) after 6 months and 73.6% (181/246) after 12 months. A slower viral suppression was observed for males than females (p value = 0.012). A total of 45.6% (52/114) individuals had at least one drug resistance mutation (DRM) detected at >20% threshold in any of the time points, and the number increased to 55% (63/114) when minor variants were accounted for. Forty-eight percent (14/29) had drug resistance mutations at >5% threshold as early as 3 months into treatment. The UNAIDS target of 95% viral suppression in individuals under treatment was not observed after 12 months of treatment, and this was less successful for males. Adherence and drug resistance monitoring could be beneficial for individuals harbouring resistant viruses early into treatment.

MiR-29a-laden extracellular vesicles efficiently induced apoptosis through autophagy blockage in HCC cells

BackgroundIn spite of significant advancements in theraputic modalities for hepatocellular carcinoma (HCC), there is still a high annual mortality rate with a rising incidence. Major challenges in the HCC clinical managment are related to the development of therapy resistance, and evasion of tumor cells apoptosis which leading unsatisfactory outcomes in HCC patients. Previous investigations have shown that autophagy plays crucial role in contributing to drug resistance development in HCC. Although, miR-29a is known to counteract authophagy, increasing evidence revealed a down-regulation of miR-29a in HCC patients which correlates with poor prognosis. Beside, evidences showed that miR-29a serves as a negative regulator of autophagy in other cancers. In the current study, we aim to investigate the impact of miR-29a on the autophagy and apoptosis in HCC cells using extracellular vesicles (EVs) as a natural delivery system given their potential in the miRNA delivery both in vitro and in vivo. MethodHuman Wharton’s Jelly mesenchymal stromal cell-derived extracellular vesicles were lately isolated through 20,000 or 110,000 × g centrifugation (EV20K or EV110K, respectively), characterized by western blot (WB), scanning electron microscopy (SEM), and dynamic light scattering (DLS). miR-29a was subsequently loaded into these EVs and its loading efficiency was evaluated via RT-qPCR. Comprehensive in vitro and in vivo assessments were then performed on Huh-7 and HepG2 cell lines. ResultsEV20K-miR-29a treatment significantly induces cell apoptosis and reduces both cell proliferation and colony formation in Huh-7 and HepG2 cell lines. In addition, LC3-II/LC3-I ratio was increased while the expression of key autophagy regulators TFEB and ATG9A were downregulated by this treatment. These findings suggest an effective blockade of autophagy by EV20K-miR-29a leading to apoptosis in the HCC cell lines through concomitant targeting of critical mediators within each pathway.

Tracking clonal evolution of drug resistance in ovarian cancer patients by exploiting structural variants in cfDNA.

Drug resistance is the major cause of therapeutic failure in high-grade serous ovarian cancer (HGSOC). Yet, the mechanisms by which tumors evolve to drug resistant states remains largely unknown. To address this, we aimed to exploit clone-specific genomic structural variations by combining scaled single-cell whole genome sequencing with longitudinally collected cell-free DNA (cfDNA), enabling clonal tracking before, during and after treatment. We developed a cfDNA hybrid capture, deep sequencing approach based on leveraging clone-specific structural variants as endogenous barcodes, with orders of magnitude lower error rates than single nucleotide variants in ctDNA (circulating tumor DNA) detection, demonstrated on 19 patients at baseline. We then applied this to monitor and model clonal evolution over several years in ten HGSOC patients treated with systemic therapy from diagnosis through recurrence. We found drug resistance to be polyclonal in most cases, but frequently dominated by a single high-fitness and expanding clone, reducing clonal diversity in the relapsed disease state in most patients. Drug-resistant clones frequently displayed notable genomic features, including high-level amplifications of oncogenes such as CCNE1 , RAB25 , NOTCH3 , and ERBB2 . Using a population genetics Wright-Fisher model, we found evolutionary trajectories of these features were consistent with drug-induced positive selection. In select cases, these alterations impacted selection of secondary lines of therapy with positive patient outcomes. For cases with matched single-cell RNA sequencing data, pre-existing and genomically encoded phenotypic states such as upregulation of EMT and VEGF were linked to drug resistance. Together, our findings indicate that drug resistant states in HGSOC pre-exist at diagnosis and lead to dramatic clonal expansions that alter clonal composition at the time of relapse. We suggest that combining tumor single cell sequencing with cfDNA enables clonal tracking in patients and harbors potential for evolution-informed adaptive treatment decisions.

Identification of an m6A Natural Inhibitor, Lobeline, That Reverses Lenvatinib Resistance in Hepatocellular Tumors.

Hepatocellular carcinoma (HCC) is an aggressive cancer that has an effect on human health. As a first-line drug for HCC, despite its excellent efficacy, lenvatinib (Len) is prone to developing drug resistance in HCC patients. The N6-methyladenosine (m6A) modification is not only related to the development of HCC but also shows great potential in overcoming HCC resistance. Using Dot Blot, our group first screened a small molecule m6A regulator, lobeline (Lob), from a library of 390 compounds (mostly natural products). In vitro experiments demonstrated that Lob could significantly enhance the sensitivity to Len of Len-resistant HCC (HCC/Len) and inhibit migration of resistant cells. In Len-resistant cell-derived and patient-derived xenograft models, Lob could reverse the resistant phenotype, with reductions in tumor volume of 68% and 60%, respectively. Furthermore, MeRIP-m6A sequencing results indicated that the underlying molecular mechanism of Lob reversal of HCC drug resistance was related to UBE3B. Taken together, this study highlighted that Lob, a plant derived natural product, could reverse the resistance of HCC to Len by regulating the m6A levels. It is hoped that this will provide a pharmacological research basis for the clinical treatment of HCC patients.

Antimicrobial Activity of Gallium(III) Compounds: Pathogen-Dependent Targeting of Multiple Iron/Heme-Dependent Biological Processes.

Metals play vital roles in biological systems, with iron/heme being essential for cellular and metabolic functions necessary for survival and/or virulence in many bacterial pathogens. Given the rise of bacterial resistance to current antibiotics, there is an urgent need for the development of non-toxic and novel antibiotics that do not contribute to resistance to other antibiotics. Gallium, which mimics iron, has emerged as a promising antimicrobial agent, offering a novel approach to combat bacterial infections. Gallium does not have any known functions in biological systems. Gallium exerts its effects primarily by replacing iron in redox enzymes, effectively inhibiting bacterial growth by targeting multiple iron/heme-dependent biological processes and suppressing the development of drug resistance. The aim of this review is to highlight recent findings on the mechanisms of action of gallium and provide further insights into the development of gallium-based compounds. Understanding the mechanisms underlying gallium's biological activities is crucial for designing drugs that enhance their therapeutic therapies while minimizing side effects, offering promising avenues for the treatment of infectious diseases.

Deoxyshikonin: a promising lead drug grass against drug resistance or sensitivity to Helicobacter pylori in an acidic environment.

Helicobacter pylori (H. pylori) is closely associated with the diseases such as gastric sinusitis, peptic ulcers, and gastric adenocarcinoma. Its drug resistance is very severe, and new antibiotics are urgently needed. Nine comfrey compounds were screened by antimicrobial susceptibility testing, among which deoxyshikonin had the best inhibitory effect, with a minimum inhibitory concentration (MIC) of 0.5-1 µg/mL. In addition, deoxyshikonin also has a good antibacterial effect in an acidic environment, it is highly safe, and H. pylori does not readily develop drug resistance. Through in vivo experiments, it was proven that deoxyshikonin (7 mg/kg) had a beneficial therapeutic effect on acute gastritis in mice infected with the multidrug-resistant H. pylori BS001 strain. After treatment with desoxyshikonin, colonization of H. pylori in the gastric mucosa of mice was significantly reduced, gastric mucosal damage was repaired, inflammatory factors were reduced, and the treatment effect was better than that of standard triple therapy. Therefore, deoxyshikonin is a promising lead drug to solve the difficulty of drug resistance in H. pylori, and its antibacterial mechanism may be to destroy the biofilm and cause an oxidation reaction.

Oleuropein mediated autophagy begets antimalarial drug resistance.

Drug resistance in Plasmodium falciparum presents a formidable challenge to the humanity. And, unavailability of an effective vaccine worsens the situation further. Autophagy is one of the mechanisms employed by parasite to evade drug pressure to survive. Autophagy induced by the P. falciparum in response to the oleuropein pressure may answer many questions related to the parasite survival as well as evolving drug tolerance. The survival/autophagy axis could be an important avenue to explore in order to address certain questions related to the evolution of drug resistance. In addition, humanized mouse model of P. falciparum infection could serve as an important preclinical tool to investigate the oleuropein-induced autophagy, potentially helping to dissect the mechanisms underlying the development of antimalarial drug resistance.

Advancements in second-line treatment research for hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors, characterized by high incidence and mortality rates. Due to its insidious onset, most patients are diagnosed at an advanced stage, often missing the opportunity for surgical resection. Consequently, systemic treatments play a pivotal role. In recent years, an increasing number of drugs have been approved for first-line systemic treatment of HCC. However, their efficacy is limited, and some patients develop drug resistance after a period of treatment. For such patients, there is currently a lack of standard second-line systemic treatment options. This review summarizes the latest advancements in second-line systemic treatment research for HCC patients who have developed resistance to various first-line systemic treatments, aiming to provide more rational and personalized second-line treatment strategies.

Biocontrol potential of Bacillus velezensis QF-2 isolated from rhizosphere soil of Vickifunkia tianschanica

Plant diseases caused by pathogenic fungi result in substantial losses of human, material, and financial resources annually. The common practice of chemical control often leads to the development of drug resistance in target organisms and carries adverse environmental impacts. As an alternative, researchers are exploring the potential of microbial control agents found in the rhizosphere.Previous studies have identified numerous promising microbial strains that could be utilized as effective, ecologically-friendly, and sustainable solutions to manage plant diseases. In the present investigation, a bacterial strain designated QF-2 was isolated from the rhizosphere soil of Vickifunkia tianschanica. Through dual culture experiments and molecular biological analysis, the taxonomic status of this strain was clearly established, and its antagonistic activities against seven plant pathogens were observed. Furthermore, the researchers conducted a comprehensive analysis of the QF-2 genome. Concurrently, five secondary metabolites (1–5) produced by QF-2 were studied, isolated, and identified.

A proteomics and transcriptome analysis provides insight into the molecular mechanisms of tea tree oil against Aeromonas hydrophila

Aeromonas hydrophila is a widespread fish pathogen. However, due to the extensive use of antibiotics in aquaculture, this bacterium has developed drug resistance. In recent years, tea tree oil, extracted from Melaleuca alternifolia, has gained widespread application in antibacterial research. Nevertheless, the underlying mechanism of action of tea tree oil on A. hydrophila remains unclear. In this study, the inhibitory effect of tea tree oil on A. hydrophila was analyzed, and its mechanism of action was elucidated through a combination of transcriptome and proteome analyses. In the current work, tea tree oil (0.039 mg/mL) significantly inhibited the growth of A. hydrophila and changed the permeability of the cell membrane. A total of 109 differentially expressed genes (DEGs) were identified by the combined analysis of the transcriptome and the proteome, of which 46 were upregulated and 63 were downregulated. These co-regulated DEGs were primarily enriched in metabolic pathways such as bacterial chemotaxis, pyrimidine metabolism, and the two-component system. Simultaneously, it was found that the target proteins of tea tree oil, such as secB, yajC, rpsP, rplL, and rpsT were significantly downregulated. These findings suggested that the potential of tea tree oil as an alternative to antibiotics in inhibiting the growth of A. hydrophila. It provides new insights into the molecular mechanisms underlying the antimicrobial activity of tea tree oil against A. hydrophila.

Discovery of novel dihydropyrrolidone-thiadiazole compound crosstalk between the YycG/F two-component regulatory pathway and cell membrane homeostasis to combat methicillin-resistant Staphylococcus aureus

The rapid emergence and spread of multidrug-resistant (MDR) Gram-positive pathogens present a significant challenge to global healthcare. Methicillin-resistant Staphylococcus aureus (MRSA) is a particular concern because of its high resistance to most antibiotics. Based on our previously reported chemical structure of compound 62, a series of novel derivatives were synthesized and evaluated for their antibacterial activities. We found that some of these derivatives displayed effective antibacterial activity against Gram-positive pathogens, with minimal cytotoxicity (CC50>100 μM) and hemolytic activity (HC50>200 μM). Among these derivatives, the minimum inhibitory concentration (MIC) of 62-7c against Gram-positive bacterial isolates ranged from 6.25 to 25 μM. This derivative also exhibited significant synergistic antibacterial effects with daptomycin both in vitro and in vivo, with an ability to eradicate planktonic and persister cells of MRSA. Additionally, 62-7c inhibited biofilm formation and eradicated mature biofilms of MRSA. Mechanistic studies revealed that 62-7c inhibited the YycG kinase activity and disrupted the cell membrane by binding to cardiolipin (CL), leading to cell death. Importantly, no development of drug resistance was observed even after 20 serial passages. Furthermore, 62-7c exhibited high biosafety and potent effectiveness in combating infections in both mouse pneumonia and mouse wound models infected with MRSA. Thus, our study revealed that 62-7c has the potential to serve as a novel antibacterial agent for treating MRSA infections.

Controlling Alveolar Bone Loss by Hydrogel‐Based Mitigation of Oral Dysbiosis and Bacteria‐Triggered Proinflammatory Immune Response

AbstractPeriodontitis is a chronic infection where abnormal host‐microbiota interactions alter the oral microbiome, trigger a proinflammatory immune response, and cause inflammatory alveolar bone loss. While antibiotics are occasionally necessary for treating periodontitis, their use must be carefully managed to prevent the development of drug resistance and oral dysbiosis. Therefore, it's crucial to develop new treatment strategies for periodontitis that reduce antibiotic dependence while effectively controlling the inflammation triggered by bacteria. In this study, a hydrogel is engineered by grafting cationic polyamidoamine dendrimers (PAMAM‐G3) onto the oxidized carboxymethyl cellulose (OCMC) backbone, resulting in an injectable cationic hydrogel (OCMC‐PAMAM‐G3, O‐P). This hydrogel can capture anionic microbial‐associated molecular patterns (MAMPs), such as lipopolysaccharides (LPS) and cell‐free DNA (cfDNA). These findings reveal that using O‐P application circumvents the disruption of the oral mucosa microbiome caused by traditional antibiotics. Additionally, this hydrogel can mitigate inflammatory alveolar bone loss in a ligature‐induced periodontitis mouse model by alleviating the LPS/cfDNA‐TLR4/9 pathway. Moreover, topical administration of O‐P hydrogel has no significant adverse effects on the oral mucosa microbiome while improving the local subgingival microbiome. The study highlights a strategy targeting MAMPs while avoiding antibiotics, as it can mitigate the bacteria‐triggered proinflammatory immune response and potentially preserve oral dysbiosis.

Dual drug-loaded tumor-targeted polymeric nanoparticles for enhancing therapeutic response in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease where standard-of-care chemotherapeutic drugs have limited efficacy due to the development of drug resistance and poor drug delivery caused by a highly desmoplastic tumor microenvironment. Combining multiple drugs in a tumor-targeting carrier would be a favorable approach to overcome these limitations. Hence, a tumor-targeted peptide (TTP) conjugated amphiphilic tri-block copolymer was developed to make targeted polymer nanoparticles (TTP-PNPs) serving as a vehicle for carrying gemcitabine (Gem), paclitaxel (PTX), and their combination (Gem + PTX). The TTP-PNPs in the form of empty polymer (P), single drug-loaded [P(Gem) and P(PTX)], and dual drug-loaded [P(Gem + PTX)] polymer nanoformulations exhibited stable and homogenous spherical shapes with 110–160 nm size. These nanoformulations demonstrated excellent stability under in vitro physiological conditions and led to an efficient release of the drugs in the presence of reduced glutathione (GSH). The efficacy of these nanoparticles was thoroughly evaluated in vitro and in vivo, demonstrating a notable capacity to selectively target and restrict PDAC cells (PANC-1 and KPC) growth. The cellular uptake and biodistribution study showed a significantly higher tumor-targeting ability of TTP-PNPs than PNPs without TTP. Notably, P(Gem + PTX) exhibited the lowest IC50 compared to all other controls and showed heightened synergistic effects in both cell lines. Furthermore, P(Gem + PTX) showed a significantly better tumor reduction and median overall survival in mouse models than single drug-loaded TTP-PNPs or a combination of free drugs (Gem + PTX). In summary, our TTP-PNP system shows great promise as a novel platform for delivering Gem + PTX specifically to pancreatic cancer (PC), maximizing the therapeutic benefits with lower concentrations of the drugs and potentially reducing toxic side effects.

UGT1A7 altered HER2-positive breast cancer response to trastuzumab by affecting epithelial-to-mesenchymal transition: A potential biomarker to identify patients resistant to trastuzumab treatment.

HER2-positive (HER2+) breast cancer accounts for 20-30% of all breast cancers. Although trastuzumab has significantly improved the survival of patients with HER2+ breast cancer, more than 70% of patients develop drug resistance within one year of treatment. Differential-gene-expression analysis of trastuzumab-sensitive and resistant HER2+ breast cancer cell lines from GSE15043 was performed to identify the biomarkers associated with trastuzumab resistance. Differential biomarker expression was confirmed in FFPE tissues collected from clinical HER2+ breast cancer tumor samples that were sensitive or resistant to trastuzumab treatment. UGT1A7, a member of the uronic acid transferase family, was associated with trastuzumab resistance. UGT1A7 expression was downregulated in trastuzumab-resistant tumor tissues and in a cell line that developed trastuzumab resistance (BT474TR). Overexpressing UGT1A7 in BT474TR restored their sensitivity to trastuzumab treatment, whereas downregulating UGT1A7 expression in parental cells led to trastuzumab resistance. Importantly, UGT1A7 localized to the endoplasmic reticulum and altered stress responses. Furthermore, downregulating UGT1A7 expression promoted epithelial-to-mesenchymal transition (EMT) by affecting TWIST, SNAIL, and GRP78 expression and the AMP-activated protein kinase signaling pathway, thus contributing to trastuzumab resistance. This study demonstrated the important role and novel mechanisms of UGT1A7 in tumor responses to trastuzumab. Low UGT1A7 expression plays an important role in EMT and contributes to trastuzumab resistance. UGT1A7 has the potential to be developed as a biomarker for identifying patients who are resistant to trastuzumab treatment.

Methuosis Inducer SGI-1027 Cooperates with Everolimus to Promote Apoptosis and Pyroptosis by Triggering Lysosomal Membrane Permeability in Renal Cancer.

The mTOR inhibitor everolimus has been approved as a sequential or second-line therapy for renal cell carcinoma (RCC). However, the development of drug resistance limits its clinical applications. This study aims to address the challenge of everolimus resistance and provide new insights into the treatment of advanced RCC. Here, the cytotoxicity of the DNA methyltransferase 1 (DNMT1) inhibitor SGI-1027 in inducing cell vacuolation and methuosis is discovered and demonstrated for the first time. Additionally, SGI-1027 exerts synergistic effects with everolimus, as their combination suppresses the growth, migration, and invasion of renal cancer cells. Mechanistically, apoptosis and GSDME-dependent pyroptosis triggered by lysosomal membrane permeability (LMP) are observed. The upregulation of GSDME expression and increased lysosomal activity in renal cancer cells provide a therapeutic window for the combination of these two drugs to treat renal cancer. The combination treatment exhibits effective anti-tumor activity and is well tolerated in a subcutaneous tumor model. Overall, this study validates and reveals the specific cytotoxicity property of SGI-1027 and its potent synergistic effect with everolimus, offering new insights into advanced RCC therapy and everolimus-resistance overcoming.