Ligustroflavone mediates the resistance of non-small cell lung cancer to osimertinib by arresting G1/S phase / 药学学报

Natural products are an important source for the development of antitumor lead compounds, but the pharmacological effects and regulatory mechanisms of natural products in osimertinib resistance in non-small cell lung cancer (NSCLC) are not well understood. The natural product ligustroflavone was used as the research object to analyze its efficacy in osimertinib-resistant NSCLC cells by cell proliferation assay and cell cycle detection. The potential targets of ligustroflavone in osimertinib-resistant NSCLC cells were screened by public databases and bioinformatics, molecular docking and microscale thermophoresis were used to identify the interaction between privet and target molecules. Western blot was used to detect the effect of privet on the target molecules and their downstream pathways. Ligustroflavone reduced the proliferation of osimertinib-resistant NSCLC cells, and could arrest the cell cycle. Cyclin-dependent kinase 6 (CDK6) was the potential target of ligustroflavone in osimertinib-resistant NSCLC cells. Ligustroflavone inhibited the activation of CDK6-Rb axis. Together, ligustroflavone could regulate osimertinib resistance in NSCLC cells by binding cell cyclin-related molecules. This study provides a theoretical basis for the targeted drug resistance of NSCLC with natural products, and also provides a new idea for the development of clinical drug combination.

Current advances of CRISPR/Cas system in antibacterial field / 药学学报

A breakthrough in molecular biology for the twenty-first century is CRISPR/Cas gene editing, which has been used in a variety of fields due to its simplicity, adaptability, and targeting. Given the current global challenge of severe bacterial resistance, difficulties in detecting antimicrobial resistance, and slow development of antimicrobial drugs, CRISPR/Cas gene-editing technology offers a promising avenue for the development of antibacterial treatments. On the one hand, CRISPR/Cas gene editing technology helps advance the study of bacterial functions and serves as a toolbox. For instance, Cas proteins and exogenous repair systems enable efficient and precise gene editing, nCas proteins and deaminase systems facilitate template-free and single base precision editing, dCas proteins and reverse transcriptase allow for repair-free gene editing, and dCas proteins and modified sgRNA enable gene expression level regulation and gene function analysis. On the other hand, its specific gene recognition and targeted DNA cleavage characteristics can be used for pathogen detection, elimination of drug-resistant bacteria and genes, and hold promise as a new strategy for clinical diagnosis and treatment.

Research progress of targeted degradation of Mycobacterium tuberculosis proteins / 药学学报

Tuberculosis (TB), an infectious disease caused by Mycobacterium tuberculosis (Mtb), is still one of the significant threats to human life. In recent years, the continuous exploration of small molecule inhibitors represented by bedaquinoline has brought new vitality into the field of tuberculosis. However, small molecule inhibitors will inevitably occur acquired drug resistance during clinical medication. As a new pharmacological mechanism, targeted protein degradation (TPD) achieves efficacy by destroying rather than inhibiting protein targets. It might be an excellent strategy to develop anti-tuberculosis drugs based on the TPD concept to solve drug resistance. This article reviews the protein degradation pathways of Mtb, such as the Pup proteasome system and the ClpP-ClpC1 complex enzyme system. The future development of these strategies into TPD drugs was prospected and summarized.

Advances in understanding leukemia bone marrow microenvironments / 药学学报

The bone marrow microenvironment, also known as the bone marrow niche, plays a critical role in maintaining the functions of hematopoietic stem cells. Under physiological conditions, various bone marrow cells regulate each other to sustain hematopoietic homeostasis. However, bone marrow cells gain abnormal function under pathological conditions to cause and promote the occurrence of leukemia and induce drug resistance. Recent findings indicate that abnormal proliferation and differentiation are not the sole reason to cause leukemia. Different types of bone marrow cells also induce intercellular adhesion, abnormally secrete cytokines and chemokines, accelerating leukemia's progress. This article reviews the multiple signaling pathways that regulate the formation and progress of leukemia bone marrow niche, such as C-X-C motif chemokine ligand 12/C-X-C motif chemokine receptor 4 signaling pathway, et al. It emphasizes that targeting leukemia bone marrow niche is a vital strategy for improving the leukemia treatment.

Recent advances in mechanisms of KRASG12C inhibitors anti-tumor resistance and relevant overcoming strategies / 药学学报

KRAS is one of the most frequently mutated human oncogenes. In spite of mounting efforts on the development of direct or indirect inhibition targeting KRAS, little has been achieved because of insurmountable difficulties, titling KRAS "undruggable". Recently, subtype-specific inhibitors have shown great hope. Some KRASG12C inhibitors have entered clinical trials, including adagrasib and sotorasib, and have shown preliminary clinical effectiveness. Experiences from the inhibitors targeting the downstream factors of RAS pathways show that the anticancer activity of these drugs will be limited due to the development of drug resistance. Preclinical studies of KRASG12C inhibitors have revealed that the application of these agents might be hampered by the drug resistance issue. The current review aims to describe the current status of KRASG12C inhibitors, and discuss the mechanisms underlying KRASG12C inhibitor resistance, so as to provide the clues for the combat of drug resistance.

Preparation of mitochondrial targeted calcium arsenite/doxorubicin lipid nanoparticles and the in vitro study in reversing tumor drug resistance / 药学学报

This study aims at the critical role of P-glycoprotein (P-gp) in tumor drug resistance, taking advantage of the adenosine triphosphate (ATP) dependence of P-gp mediated drug transport and efflux across the cell membrane. Mitochondrial targeted calcium arsenite/doxorubicin (DOX) lipid nanoparticles were constructed via hydrothermal method and thin-film dispersion method for reversing tumor drug resistance. The results showed that the lipid nanoparticles were uniform in size and well dispersed with a mean particle size of (261 ± 7) nm, zeta potential of (-9.6 ± 1.3) mV. The DOX loading efficiency and encapsulation efficiency were 22.6% and 84.0%. The in vitro drug release profile was pH-dependent; the drug accumulation at mitochondria was significantly increased, which then caused overload of calcium and inhibition of P-gp and ATP, thereby reversing tumor drug resistance. The simultaneously released arsenite ion and DOX could synergistically kill the tumor cells. In summary, the lipid nanoparticles prepared in this study have uniform particle size, high drug loading efficiency and encapsulation efficiency, excellent colloidal stability, pH responsiveness, and impressive ability to reverse tumor drug resistance, which may hold great potential in further clinical applications.

Application and mechanism of nanomedicine in antifungal infection therapy / 药学学报

The threat of fungal diseases is increasingly rigorous. The clinically invasive fungal infections remain a main cause of morbidity and mortality in certain high-risk groups, especially in critical patients or immunocompromised patients. In drug therapy, the problems of off-target toxicity and antifungal drug resistance are still challenging. With the wide application of biomaterials and nanotechnology, more nanomedicine studies have been carried out on antifungal drugs, such as the amphotericin B liposome which greatly reduced the renal toxicity of drugs has been successfully marketed. For the unique physical and chemical properties, the nano-drug delivery system possessed great potential in improving the bioavailability, reducing the side effects of drugs, increasing the stability of drugs, and achieving cells or tissue-specificity through the modification. This review summarized the applications and limitations of antifungal drugs. Some nanomedicines were summarized in discussion oriented around the antifungal therapy, including liposomes, niosomes, lipid nanoparticles, polymer nanoparticles, microemulsion, dendrimers, inorganic nanocarriers. Nanotechnology and nano-drug delivery system provide promising strategies for the research and development of new formulations that can improve antifungal activity and possibly overcome antifungal drug resistance.

Advances in drug delivery strategies against Helicobacter pylori / 药学学报

italic>Helicobacter pylori (H. pylori) can cause a variety of digestive tract diseases, the serious may develop into gastric cancer. Nowadays, H. pylori infection rate exceeds 50%, and its eradication rate is declining due to the continuous increase of drug resistance, leading to the occurrence of plenty of stubborn infections, which seriously threaten human health. At present, it is difficult to achieve satisfactory curative effect by increasing the types of antibiotics combination or increasing their dose. In this review, the clinical treatments of H. pylori were introduced. Proceed from the characteristics and pathological background of H. pylori infection that makes H. pylori difficult to eradicate, the research advances of drug delivery strategies for improving H. pylori eradication rate were reviewed, such as strategies that could increase drug concentration in stomach (e.g. drug delivery systems with gastric acid-stabilized ability), increase drug concentration in H. pylori colonization sites (e.g. drug delivery systems with gastric retention or H. pylori targeted abilities), overcome H. pylori resistance (metal nanoparticles, anti-biofilm delivery systems), enhance host immune response (vaccine preparation) and so on. Novel drug delivery systems, such as cell membrane coating technology and phage therapy, are comparatively rare in the field of anti-H. pylori, but have broad application prospects. This review would provide reference for the development and application of therapeutic strategies to improve H. pylori eradication rate.

The research progress of PROTACs for breast cancer treatment / 药学学报

Breast cancer is the most common malignant tumor in women worldwide. In breast cancer tumor tissues, a variety of targets related to the occurrence and development of breast cancer have been observed, and many drugs have been used in clinical applications for these targets. However, most of these drugs are small molecule inhibitors. With the long-term use of these drugs, acquired drug resistance often occurs in breast cancer patients. To overcome the drug resistance, the development of more efficient drugs is highly desirable in the treatment of breast cancer. Proteolysis targeting chimera (PROTAC) technology is a new kind of targeted protein degradation technology, which has shown broad prospect of applications in the field of drug development. The use of PROTAC technology to target the degradation of relevant targets in breast cancer has become a feasible strategy for breast cancer treatment.

The application of small molecule PROTAC in researches of different targets / 药学学报

The protein proteolysis-targeting chimeras (PROTAC) are a kind of bifunctional compound that can recruit target proteins and degrade the enzyme of target proteins. The mechanism of PROTAC is using the ubiquitin-proteasome pathway to degrade target protein specifically. Because of its potential to target non-proprietary proteins and to play roles in drug resistance, PROTAC has attracted wide attention. This review summarizes the application of small molecule PROTAC in previous studies of different targets, such as nuclear proteins, membrane proteins and cytoplasmic proteins.

Multidrug resistance and risk factors associated with community-acquired urinary tract infections caused by Escherichia coli in Venezuela / Multirresistencia a medicamentos y factores de riesgo asociados con infecciones urinarias por Escherichia coli adquiridas en la comunidad, Venezuela

Abstract Introduction: The treatment of urinary tract infections has become more challenging due to the increasing frequency of multidrug-resistant Escherichia coli in human populations. Objective: To characterize multidrug-resistant E. coli isolates causing community-acquired urinary tract infections in Cumaná, Venezuela, and associate possible risk factors for infection by extended-spectrum beta-lactamases (ESBL)-producing isolates. Materials and methods: We included all the patients with urinary tract infections attending the urology outpatient consultation and emergency unit in the Hospital de Cumaná, Estado Sucre, Venezuela, from January through June, 2014. blaTEM, blaSHV and blaCTX-M genes detection was carried out by PCR. Results: We found a high prevalence of multidrug-resistant E. coli (25.2%) with 20.4% of the isolates producing ESBL. The ESBL-producing isolates showed a high frequency (66.7%) of simultaneous resistance to trimethoprim-sulphamethoxazole, fluoroquinolones and aminoglycosides compared to non-producing isolates (2.4%). Of the resistant isolates, 65.4% carried the blaTEM gene, 34.6% the blaCTX-M and 23.1% the blaSHV. The blaCTX-M genes detected belonged to the CTX-M-1 and CTX-M-2 groups. Plasmid transfer was demonstrated by in vitro conjugation in 17 of the 26 ESBL-producing isolates. All three genes detected were transferred to the transconjugants. Age over 60 years, complicated urinary tract infections and previous use of a catheter predisposed patients to infection by ESBL-producing E. coli. Conclusions: The high frequency of multidrug-resistant ESBL-producing isolates should alert the regional health authorities to take measures to reduce the risk of outbreaks caused by these types of bacteria in the community.

Resumen Introducción. El tratamiento de las infecciones urinarias constituye un reto creciente por el aumento de Escherichia coli proveniente de la comunidad multirresistente a los medicamentos. Objetivo. Caracterizar aislamientos de E. coli multirresistente causantes de infecciones urinarias adquiridas en la comunidad en Cumaná, Venezuela, y detectar los posibles riesgos de infección por aislamientos productores de betalactamasas de espectro extendido (BLEE). Materiales y métodos. Se incluyeron todos los pacientes atendidos en la consulta externa de urología y en urgencias del Hospital de Cumaná entre enero y junio de 2014 y que evidenciaban infecciones urinarias. La detección de los genes blaTEM, blaSHV y blaCTX-M se hizo mediante la reacción en cadena de la polimerasa (PCR). Resultados. Se encontró una alta prevalencia de E. coli multirresistente a los medicamentos (25,2 %), con 20,4 % de aislamientos productores de BLEE y una gran frecuencia de resistencia simultánea a trimetoprim-sulfametoxazol, fluoroquinolonas y aminoglucósidos (66,7 %) comparados con los no productores (2,4 %). En el 65,4 % de los aislamientos resistentes, se encontró el gen blaTEM; en 34,6 %, el blaCTX-M, y en 23,1 %, el blaSHV. Los genes blaCTX-M detectados pertenecían a los grupos CTX-M-1 y CTX-M-2. Se demostró la transferencia in vitro de plásmidos por conjugación en 17 de los 26 aislamientos productores de BLEE. Los tres tipos de genes detectados se transfirieron a los transconjugantes. La edad mayor de 60 años, las infecciones urinarias con complicaciones y el uso previo de catéter, predispusieron a la infección por cepas de E. coli productoras de BLEE. Conclusiones. La gran frecuencia de aislamientos multirresistentes productores de BLEE debería alertar a las autoridades sanitarias para tomar medidas que reduzcan el riesgo de epidemias causadas por este tipo de bacterias en la comunidad.

The mechanism and research progress of drug resistance of PD-1/PD-L1 immunotherapy in tumors / 药学学报

Programmed cell death protein 1 (PD-1) is an important immunosuppressive molecule, which combines with programmed cell death 1 ligand 1 (PD-L1) to initiate programmed T-cell death, leading to immune escape of tumor cells. Immune checkpoint inhibitors kill tumor cells by blocking the binding of PD-1 to PD-L1 and reactivating the patient's own immune system. With the approval of anti-PD-1 monoclonal antibodies nivolumab, pembrolizumab and anti-PD-L1 monoclonal antibody atezolizumab by FDA for the treatment of melanoma, advanced non-small cell lung cancer and other cancers, cancer treatment has ushered in a new dawn. However, only 20% of patients achieved long-term efficacy after treatment, and most patients relapsed later. Therefore, it is significant to identify effective biomarkers and develop new targets to improve the response of patients to immunotherapy. This article reviews on the mechanism of action of anti-PD-1/PD-L1 drugs in tumors, potential biomarkers and the mechanism of acquired drug resistance, as well as combination therapy under research.

Recent advances in study of drugs against Gram-negative pathogens / 药学学报

The long-term use of antibiotics in clinical practice leads to bacterial variation and resistance. In addition, the excessive or improper use of antibiotics in medical and agricultural fields increases the occurrence of bacterial resistance. In 2017, the World Health Organization has for the first time released a list of 12 bacteria or bacterial families that pose the greatest threat to human health and for which new antibiotics are desperately needed, and three quarters of them are Gram-negative bacteria. Gram-negative bacteria has multi-layered cell wall that prevents many antibiotics from accessing their targets. Therefore, it is very difficult to develop drugs against Gram-negative bacteria, no new class of antibiotic has been approved for Gram-negative pathogens in over fifty years. Here, we summarized recent advances in the study of new antibacterial agents with different mechanisms of action against Gram-negative pathogens.

The roles of sphingosine-1-phosphate and its receptor in Mycobacterium tuberculosis infection and novel antibiotics discovery / 药学学报

Tuberculosis (TB) caused by Mycobacterium tuberculosis (M. tuberculosis) infection remains a major public health problem of global concern, largely due to antibiotics resistance, persistence and immune evasion. Sphingolipid bioactive molecules are involved in several important pathophysiological processes. Sphingosine-1-phosphate is a key product of sphingolipid metabolism, and can play a role in two manners: autocrine and/or paracrine. Sphingosine-1-phosphate regulates T cells and a variety of antigen-presenting cells during M. tuberculosis infection, promotes antigen processing and expression in monocytes, is involved in the maturation of phagolysosome, regulates Ca2+ homeostasis, participates in the autophagy of macrophages, inhibits the survival and proliferation of M. tuberculosis within host cells, and effectively reduces the necrosis of the mouse lungs infected by M. tuberculosis. Injection of 20 nmol per mouse sphingosine-1-phosphate inhibited up to 47% of mycobacterial growth in the lung and spleen of mice infected by M. tuberculosis. In this paper, sphingosine-1-phosphate, its receptors and regulatory network were reviewed, and the specific mechanism of sphingosine-1-phosphate inhibiting the survival of M. tuberculosis-infected host cells was elaborated. This will provide novel insights into the new targets for tuberculosis prevention and treatment.

Down-regulation of miR-205-5p sensitizes HNE1/DDP to cisplatin induced apoptosis in vitro / 药学学报

This study aims to investigate the effect of down-regulation of miR-205-5p by transfection of miR-205-5p inhibitor on the sensitivity of HNE1/DDP cells to cisplatin (DDP) induced apoptosis and explore the underlying mechanism. qRT-PCR was used to detect the expression of miR-205-5p in HNE1 or HNE1/DDP cells. The expression level of miR-205-5p was analyzed after transfecting HNE1/DDP cells with miR-205-5p inhibitor. MTT assay was used to evaluate the inhibitory effect of DDP alone or in combination with miR-205-5p inhibitor on the proliferation of HNE1/DDP or HNE1 cells. Apoptosis of cells treated with miR-205-5p inhibitor alone or in combination with DDP (8 μmol·L-1) was assessed using flow cytometry with PI staining, with the nucleus was counterstained with DAPI staining. The expression of Bax, Bak, Mcl-1, or Bcl-2 was analyzed by Western blot. HNE1/DDP cells showed a high level of expression of miR-205-5p, and the expression of miR-205-5p was significantly decreased by transfection of miR-205-5p inhibitor. Down-regulation of miR-205-5p significantly increased the sensitivity of HNE1/DDP cells to DDP (P<0.05). Transfection of miR-205-5p inhibitor enhanced the sensitivity of HNE1/DDP cells to DDP induced apoptosis. Treatment of HNE1/DDP cells with miR-205-5p inhibitor combined with DDP (8 μmol·L-1) for 24 h resulted in an apoptotic rate of 28.93% ± 2.50%, significantly higher than that treated with miR-205-5p inhibitor (9.83% ± 1.31%) or DDP alone (10.83% ± 1.70%) (P<0.05). DAPI staining showed that HNE1/DDP cell nucleus became significantly condensed and fragmented in miR-205-5p inhibitor combined with DDP group. The combined group up-regulated the expression of Bax and down-regulated the expression of Bcl-2 in HNE1/DDP cells. Therefore, down-regulation of miR-205-5p can enhance the sensitivity of HNE1/DDP cells to cisplatin induced apoptosis, and the mechanism may involve up-regulation of Bax and down-regulation of Bcl-2 expression.

Mechanisms of doxorubicin resistance of breast cancer MCF-7 cells mediated by exosomes / 药学学报

This study aimed to explore the roles of exosomes in doxorubicin-resistance in breast cancer cells. Using breast cancer parental cell line (MCF-7), doxorubicin-resistant cell line (MCF-7/ADR) and sensitive cell line co-cultured with doxorubicin-resistant supernatant (MCF-7/EXO) as models, the effects of doxorubicin on proliferation or apoptosis of MCF-7, MCF-7/EXO and MCF-7/ADR cells were detected by CCK8, and light or fluorescent microscopy. Exosomes in the supernatants of cell culture were extracted by ultracentrifugation, and the quantity of exosomes was determined by transmission electron microscopy, BCA and DiI labeling assay. Expression levels of exosome-specific biomarkers CD63 and Flotillin-1 were detected by Western blot. The uptake of MCF-7/ADR cell-derived exosomes by MCF-7 cells was observed by laser confocal microscopy. Western blot was used to detect the expression levels of multidrug resistance protein ATP-binding cassette subfamily B member 1 (ABCB1) in all three cell strains. Cell proliferation assays showed that IC50 of MCF-7/EXO cells to doxorubicin was 0.83 ± 0.09 μmol·L-1, which was significantly higher than 0.15 ± 0.05 μmol·L-1 (P<0.01) of MCF-7 cells, suggesting 5.5 times of increase in drug resistance. Apoptosis of MCF-7 cells was induced after doxorubicin treatment (P<0.001), but MCF-7/EXO cells were not significantly different (P>0.05). Exosome quantification and specific marker detection showed that MCF-7/EXO cells had significantly more exosomes than MCF-7 cells (P<0.05). PKH67 tracer markers indicated that MCF-7/ADR-derived exosomes could be taken up by MCF-7 cells. Western blot showed that the expression level of ABCB1 protein in MCF-7/EXO cells was significantly higher than that in MCF-7 cells. Taken together, these results indicate that exosomes of doxorubicin-resistant breast cancer cells can transmit drug resistance to sensitive cells, and the underlying mechanism may involve ABCB1 protein transport mediated by exosomes.

Advances in understanding exosomes-mediated tumor chemoresistance / 药学学报

Chemotherapy plays an essential role in controlling tumor growth and progression. However, long-term use of chemotherapeutic drugs usually results in drug resistance in tumor cells, leading to treatment failure and disease progression. The mechanism of tumor resistance to chemotherapy and the strategy of prevention or reversal of such resistance have always been hot issues in cancer therapy research. Exosomes are small spherical vesicles secreted by cells with a diameter of 40-100 nm. They carry a variety of bioactive small molecules (including DNA, ncRNA, RNA, and proteins) and participate in regulation of cell microenvironment, thereby affecting a variety of physiological and pathological activities in the body. In recent years, studies have shown that exosomes play an important role in cancer cell resistance to chemotherapy, metastasis, and immune escape. This article reviews the role and mechanism of exosomes in the development of drug resistance in tumors, and aims to provide new ideas for the prevention or treatment of tumor resistance.