Comparative assessment of nanosized intracanal medicaments on penetration and fracture resistance of root dentin - An in vitro study.

Context: The antimicrobial potential of conventional medicaments is reduced due to their limited permeability. The use of calcium hydroxide (CH) is known to reduce the root strength. Nano intracanal medicaments have the following advantages over conventional such as higher surface area and chemical reactivity, and due to its nanosize, have better penetrability, supporting its possible use as an intracanal medicament. Nano versions of CH, chitosan (CS), CS + CH, curcumin (T), and its conventional forms are used in our study. Aim: The aim of this study was to evaluate and compare the depth of penetration of nanosized intracanal medicaments and their effect on fracture resistance of root dentin. Materials and Methods: Eighty extracted single-rooted teeth were used after decoronation. Canals were enlarged up to size 30 (0.04° taper) using Neoendo instruments (Orikam, India). Teeth were randomly assigned to two broad groups based on the type of intracanal medicament used; Group A: control (conventional) (n = 40) and Group B: nanosized intracanal medicaments (n = 40). Each group was subdivided into four experimental groups (n = 10), Group A1: CH, Group A2: CS, Group A3: curcumin (T), Group A4: CS + CH, Group B1: nano calcium hydroxide (NCH), Group B2: nano CS (NCS), Group B3: nano curcumin (NT), and Group B4: NCS + nano calcium hydroxide (NCS + NCH). All the specimens were stored in a humidor at 37°C for 4 weeks. Out of 10 specimens from each group, five specimens were used for evaluating the depth of penetration using a confocal laser scanning electron microscope, and the remaining five specimens were used for evaluating fracture resistance in a universal testing machine at the end of 4 weeks. Data were analyzed using one-way ANOVA and intergroup comparison using Tukey's post hoc multiple comparison test. Results: The highest fracture resistance was seen with NCS and the maximum depth of penetration with nano calcium hydroxide (NCH). Conclusion: The fracture resistance and depth of penetration at a 4-week interval were higher in nano forms compared to their micro-sized counterparts with all groups. The coronal section presented the highest depth of penetration of intracanal medicaments followed by the middle and least in the apical section of root dentin with all groups.

Exploring plant-derived small molecules as inhibitors of Marburg virus RNA binding protein activity.

The search for antiviral medications is greatly influenced by the hunt for potent inhibitors of viral proteins. To find possible inhibitors of the RNA binding activity of the Marburg virus VP35 protein, we used a thorough in silico drug discovery approach in this investigation. A comprehensive virtual screening process, followed by a detailed MMGBSA analysis, led to the discovery of four potential inhibitory compounds viz. Kudzuisoflavone A, Miquelianin, Rutin, and Protopseudohypericin. They were identified from an extensive library of phytomolecules derived from three medicinal plants: Adiantum capillus-veneris, Hypericum perforatum, and Pueraria montana. In molecular dynamics (MD) simulations, all these compounds showed steady binding to the target protein and favourable interactions. Notably, the free binding energies of all the selected compounds were better than the myricetin, a well-known blocker of the VP35 protein of the Ebola virus. Overall, this investigation offers insightful information about the molecular interactions and binding dynamics of the identified inhibitors' binding to the VP35 protein of the Marburg virus. The findings highlight the potential of three particular medicinal plants as sources of key chemicals for the creation of brand-new Marburg virus antiviral drugs. More experimental validation and optimization of the identified inhibitors are necessary in order to transform these findings into effective medicines for treating Marburg virus infections.Communicated by Ramaswamy H. Sarma.

Inhibition of Mycobacterium tuberculosis resuscitation-promoting factor B (RpfB) by microbially derived natural compounds: a computational study.

The majority of the world population (around 25%) has latent Mycobacterium tuberculosis (Mtb) infection, among which only 5-10% of individuals develop active tuberculosis (TB), and 90-95% continue to have latent tuberculosis infection. This makes it the biggest global health concern. It has been reported that the resuscitation-promoting factor B (RpfB) is an exciting potential target for tuberculosis drug discovery due to its significant role in the reactivation of latent TB infection to an active infection. Several attempts have been made to investigate potential inhibitors against RpfB utilizing in-silico approaches. The present study also utilized a computational approach to investigate microbially derived natural compounds against the Mtb RpfB protein which is a very cost-effective This evaluation used structure-based virtual screening (SBVS), drug-likeness profiling, molecular docking, molecular dynamics simulation, and free-binding energy calculations. Six potential natural compounds, viz. Cyclizidine I, Boremexin C, Xenocoumacin 2, PM-94128, Cutinostatin B, and (+)1-O-demethylvariecolorquinone A were selected, which displayed a potential binding affinity between -52.39 and -60.87 Kcal/mol MMGBSA score and docking energy between -7.307 Kcal/mol to -6.972 Kcal/mol. All the complexes showed acceptable stability (<2.7 Å RMSD) during 100 ns MD simulation time except the RpfB protein-xenocoumacin 2 complex. This result exhibited that the selected compounds have high efficiency in inhibiting the Mtb RpfB and can be taken into account for additional in vitro and in vivo experimental validation.Communicated by Ramaswamy H. Sarma.

Targeting neuroblastoma by small-molecule inhibitors of human ALYREF protein: mechanistic insights using molecular dynamics simulations.

Neuroblastoma is a tumour of the sympathetic nervous system mainly prevalent in children. Many strategies have been employed to target several drug-targetable proteins for the clinical management of neuroblastoma. However, the heterogeneous nature of neuroblastoma presents serious challenges in drug development for its treatment. Albeit numerous medications have been developed to target various signalling pathways in neuroblastoma, the redundant nature of the tumour pathways makes its suppression unsuccessful. Recently, the quest for neuroblastoma therapy resulted in the identification of human ALYREF, a nuclear protein that plays an essential role in tumour growth and progression. Therefore, this study used the structure-based drug discovery method to identify the putative inhibitors targeting ALYREF for the Neuroblastoma treatment. Herein, a library of 119 blood-brain barrier crossing small molecules from the ChEMBL database was downloaded and docked against the predicted binding pocket of the human ALYREF protein. Based on docking scores, the top four compounds were considered for intermolecular interactions and molecular dynamics simulation analysis, which revealed CHEMBL3752986 and CHEMBL3753744 with substantial affinity and stability with the ALYREF. These results were further supported by binding free energies and essential dynamics analysis of the respective complexes. Hence, this study advocates the sorted compounds targeting ALYREF for further in vitro and in vivo assessment to develop a drug against neuroblastoma.Communicated by Ramaswamy H. Sarma.

A comprehensive guide on screening and selection of a suitable AMP against biofilm-forming bacteria.

Lately, antimicrobial resistance (AMR) is increasing at an exponential rate making it important to search alternatives to antibiotics in order to combat multi-drug resistant (MDR) bacterial infections. Out of the several antibacterial and antibiofilm strategies being tested, antimicrobial peptides (AMPs) have shown to give better hopes in terms of a long-lasting solution to the problem. To select a desired AMP, it is important to make right use of available tools and databases that aid in identification, classification, and analysis of the physiochemical properties of AMPs. To identify the targets of these AMPs, it becomes crucial to understand their mode-of-action. AMPs can also be used in combination with other antibacterial and antibiofilm agents so as to achieve enhanced efficacy against bacteria and their biofilms. Due to concerns regarding toxicity, stability, and bioavailability, strategizing drug formulation at an early-stage becomes crucial. Although there are few concerns regarding development of bacterial resistance to AMPs, the evolution of resistance to AMPs occurs extremely slowly. This comprehensive review gives a deep insight into the selection of the right AMP, deciding the right target and combination strategy along with the type of formulation needed, and the possible resistance that bacteria can develop to these AMPs.

In Silico Study of a Small Bioactive Molecule Targeting Topoisomerase II and P53-MDM2 Complex in Triple-Negative Breast Cancer.

Treatment of triple-negative breast cancer (TNBC) is very challenging as only few therapeutic options are available, including chemotherapy. Thus, a constant search for new and effective approaches of therapy that could potentially fight against TNBC and mitigate side effects is "turn-on". Recently, multitarget therapy has come up with huge possibilities, and it may possibly be useful to overcome several concurrent challenges in cancer therapy. Herein, we proposed the inhibition of both Topoisomerase II enzyme and p53-MDM2 (p53 cavity in MDM2) protein complex by the same bioactive molecules for multitarget therapy. RNA-seq analysis was performed to get a network of essential proteins involved in the apoptosis pathway by considering the triple-negative breast cancer cell line (MDA-MB-231). All of the untreated duplicate sample data were retrieved from NCBI (GSC149768). Further, via in silico screening, potent bioactive molecules were screened out to target both Topo II and the p53-MDM2 complex. The results of ligand-based screening involving docking, MMGBSA, ADME/T, MD simulation, and PCA suggested that resveratrol, a plant bioactive molecule, showed more potential binding in the same cavity of target proteins compared with doxorubicin for Topo IIα (5GWK) and etoposide for the second protein target (p53-MDM2 complex; 4OQ3) as the control drug. This is also evident from the in vitro validation in case of triple-negative breast cancer cell lines (MDA-MB-231) and Western blotting analysis. Thus, it paves the scope of multitargeting against triple-negative breast cancer.

Identification of naturally occurring compounds as alternatives to radiation therapy for treatment of small cell lung cancer.

Radiation resistance is one of the major problems in the treatment of small cell lung cancer (SCLC). Most of these patients are given radiation as first-line treatment and it was observed that the initial response in these patients is very good. However, they show relapse in a few months which is also associated with resistance to treatment. Thus, targeting the mechanism by which these cells develop resistance could be an important strategy to improve the survival chances of these patients. From the RNA-Seq data analysis, it was identified that CHEK1 gene was overexpressed. Chk1 protein which is encoded by the CHEK1 gene is an important protein that is involved in radiation resistance in SCLC. It is known to favour the cells to deal with replicative stress. CHEK1 is the major cause for developing radiation resistance in SCLC. Thus, natural compounds that could also serve as potential inhibitors for Chk1 were explored. Accordingly; the compounds were screened based on ADME, docking and MM-GBSA scores. MD simulations were performed for the selected protein-ligand complexes and the results were compared to the co-crystallised ligand, 3-(indol-2-yl)indazole. The results showed that compound INC000033832986 could be a natural alternative to the commercial ligand for the prevention of SCLC.Communicated by Ramaswamy H. Sarma.

Strategies in design of self-propelling hybrid micro/nanobots for bioengineering applications.

Micro/nanobots are integrated devices developed from engineered nanomaterials that have evolved significantly over the past decades. They can potentially be pre-programmed to operate robustly at numerous hard-to-reach organ/tissues/cellular sites for multiple bioengineering applications such as early disease diagnosis, precision surgeries, targeted drug delivery, cancer therapeutics, bio-imaging, biomolecules isolation, detoxification, bio-sensing, and clearing up clogged arteries with high soaring effectiveness and minimal exhaustion of power. Several techniques have been introduced in recent years to develop programmable, biocompatible, and energy-efficient micro/nanobots. Therefore, the primary focus of most of these techniques is to develop hybrid micro/nanobots that are an optimized combination of purely synthetic or biodegradable bots suitable for the execution of user-defined tasks more precisely and efficiently. Recent progress has been illustrated here as an overview of a few of the achievable construction principles to be used to make biomedical micro/nanobots and explores the pivotal ventures of nanotechnology-moderated development of catalytic autonomous bots. Furthermore, it is also foregrounding their advancement offering an insight into the recent trends and subsequent prospects, opportunities, and challenges involved in the accomplishments of the effective multifarious bioengineering applications.

Finding Novel AMPs Secreted from the Human Microbiome as Potent Antibacterial and Antibiofilm Agents and Studying Their Synergistic Activity with Ag NCs.

Due to the enhanced resistance of bacteria to antibiotics, researchers always try to find effective alternatives to treat drug-resistant bacterial infections. In this context, we have explored antimicrobial peptides (AMPs), which are a broad class of small peptide molecules, and investigated their efficacy as potent antibacterial and antibiofilm agents. AMPs can cause cell death either through disruption of the cell membrane or by inhibiting vital intracellular functions, by binding to RNA, DNA, or intracellular components upon transversion through the cell membrane. We attempted to find potent intracellular cationic AMPs that can demonstrate antibacterial activity through interaction with DNA. As a source of AMPs, we have utilized those that are secreted from the human microbiome with the anticipation that these will be non-toxic in nature. Out of the total 1087 AMPs, 27 were screened on the basis of amino acid length and efficacy to cross the cell membrane barrier. From the list of 27 peptides, 4 candidates were selected through the docking score of these peptides with the DNA binding domain of H2A proteins. Further, the molecular dynamics simulation analysis demonstrated that 2 AMPs, i.e., peptides 7 and 25, are having considerable membrane permeation and DNA binding ability. Further, the in vitro analysis indicated that both peptides 7 and 25 could exhibit potent antibacterial and antibiofilm activities. In order to further enhance the antibiofilm potency, the above AMPs were used as supplements to silver nanoclusters (Ag NCs) to get synergistic activity. The synergistic activity of Ag NCs was found to be significantly increased with both the above AMPs.

Correction to "Visible Light-Mediated Photoactivated Sulfur Quantum Dots as Heightened Antibacterial Agents".

[This corrects the article DOI: 10.1021/acsomega.2c03968.].

Exploration of Microbially Derived Natural Compounds against Monkeypox Virus as Viral Core Cysteine Proteinase Inhibitors.

Monkeypox virus (MPXV) is a member of the Orthopoxvirus genus and the Poxviridae family, which instigated a rising epidemic called monkeypox disease. Proteinases are majorly engaged in viral propagation by catalyzing the cleavage of precursor polyproteins. Therefore, proteinase is essential for monkeypox and a critical drug target. In this study, high-throughput virtual screening (HTVS) and molecular dynamics simulation were applied to detect the potential natural compounds against the proteinase of the monkeypox virus. Here, 32,552 natural products were screened, and the top five compounds were selected after implementing the HTVS and molecular docking protocols in series. Gallicynoic Acid F showed the minimum binding score of -10.56 kcal/mole in the extra precision scoring method, which reflected the highest binding with the protein. The top five compounds showed binding scores ≤-8.98 kcal/mole. These compound complexes were tested under 100 ns molecular dynamics simulation, and Vaccinol M showed the most stable and consistent RMSD trend in the range of 2 Å to 3 Å. Later, MM/GBSA binding free energy and principal component analysis were performed on the top five compounds to validate the stability of selected compound complexes. Moreover, the ligands Gallicynoic Acid F and H2-Erythro-Neopterin showed the lowest binding free energies of -61.42 kcal/mol and -61.09 kcal/mol, respectively. Compared to the native ligand TTP-6171 (ΔGBind = -53.86 kcal/mol), these two compounds showed preferable binding free energy, suggesting inhibitory application against MPXV proteinase. This study proposed natural molecules as a therapeutic solution to control monkeypox disease.

Docking and molecular dynamics simulation for therapeutic repurposing in small cell lung cancer (SCLC) patients infected with COVID-19.

Cancer care has become a challenge with the current COVID-19 pandemic scenario. Specially, cancers like small cell lung cancers (SCLC) are difficult to treat even in the normal situation due to their rapid growth and early metastasis. For such patients, treatment can't be compromised and care must be taken to ensure their minimum exposure to the ongoing spread of COVID-19 infection. For this reason, in-house treatments are being suggested for these patients. Another issue is that symptoms of SCLC match well with that of COVID-19 infection. Hence, the detection of COVID-19 may also get delayed leading to unnecessary complications. Thus, we have tried to investigate if the therapeutics that is currently used in lung cancer treatment can also act against SARS-CoV-2. If it is so, the same treatment protocols can be continued even if the SCLC patient had contracted COVID-19 without compromising the cancer care. For this, RNA dependent RNA polymerase (RdRP) from SARS-CoV-2 has been selected as drug target. Both docking and molecular dynamicssimulation analysis have indicated that Paclitaxel and Dacomitinib may be explored as multi-target drugs for both SCLC and COVID-19.Communicated by Ramaswamy H. Sarma.

Nanoengineering of biohybrid micro/nanobots for programmed biomedical applications.

Biohybrid micro/nanobots have emerged as an innovative resource to be employed in the biomedical field due to their biocompatible and biodegradable properties. These are tiny nanomaterial-based integrated structures engineered in a way that they can move autonomously and perform the programmed tasks efficiently even at hard-to-reach organ/tissues/cellular sites. The biohybrid micro/nanobots can either be cell/bacterial/enzyme-based or may mimic the properties of an active molecule. It holds the potential to change the landscape in various areas of biomedical including early diagnosis of disease, therapeutics, imaging, or precision surgery. The propulsion mechanism of the biohybrid micro/nanobots can be both fuel-based and fuel-free, but the most effective and easiest way to propel these micro/nanobots is via enzymes. Micro/nanobots possess the feature to adsorb/functionalize chemicals or drugs at their surfaces thus offering the scope of delivering drugs at the targeted locations. They also have shown immense potential in intracellular sensing of biomolecules and molecular events. Moreover, with recent progress in the material development and processing is required for enhanced activity and robustness the fabrication is done via various advanced techniques to avoid self-degradation and cause cellular toxicity during autonomous movement in biological medium. In this review, various approaches of design, architecture, and performance of such micro/nanobots have been illustrated along with their potential applications in controlled cargo release, therapeutics, intracellular sensing, and bioimaging. Furthermore, it is also foregrounding their advancement offering an insight into their future scopes, opportunities, and challenges involved in advanced biomedical applications.

Recent development of multi-targeted inhibitors of human topoisomerase II enzyme as potent cancer therapeutics.

Multi-target therapies have been considered one of the viable options to overcome the challenges to eradicate intrinsic and acquired drug-resistant cancer cells. While to increase the efficacy of therapeutics, the use of a single drug against multiple structurally similar sites, which noncommittedly modulate several vital cellular pathways proposed as a potential alternative to a 'single drug single target'. Besides, it reduces the usage of a number of drugs and their side effects. Topoisomerase II enzyme plays a very significant role in DNA replication and thus served as an important target for numerous anti-cancer agents. However, in spite of promising clinical results, in several cases, it was found that cancer cells have developed resistance against the anti-cancer agents targeting this enzyme. Therefore, multi-target therapies have been proposed as an alternative to overcome different drug resistance mechanisms while topoisomerases II are a primary target site. In this review, we have tried to discuss the characteristics of the binding cavity available for interactions of drugs, and potent inhibitors concurrently modulate the functions of topoisomerases II as well as other structurally related target sites. Additionally, the mechanism of drug resistance by considering molecular and cellular insights by including various types of cancers.

Structural and thermostability insights into cellobiohydrolase of a thermophilic mould Myceliophthora thermophila: in-silico studies.

Cellobiohydrolase (CBH) is one of the cellulases with a wide range of industrial applications; it plays a pivotal role in cellulose hydrolysis and thus in biofuel production. The structural and thermostability analysis of a CBHII of the thermophilic mold Myceliophthora thermophila (MtCel6A) had been carried out using various in-silico approaches. The validation of 3 D model by the Ramachandran plot indicated 88.5% amino acid residues in the favoured regions. Docking analysis suggested MtCel6A to display a high affinity towards cellotetraose as compared to other substrates. The enzyme exhibited a high tolerance to the end product, cellobiose. The thermostability evaluation by molecular dynamic simulations and principal component analysis confirmed its tolerance to elevated temperatures. The identified thermolabile regions could be targeted for site-directed mutagenesis in order to ameliorate thermostability further. Our experimental data published earlier confirmed the present findings of in-silico studies. The structural and functional characteristics of MtCel6A highlighted its critical features that make it a useful biocatalyst in several industrial processes.Communicated by Ramaswamy H. Sarma.

Manganese Doping in Biomass Derived Carbon Dots Amplifies White Light-Induced Antibacterial Activity.

The prevalence of antibiotic-resistant bacterial infections demands effective alternative therapeutics of antibiotics, whereas biocompatible zero-dimensional nanomaterials are an excellent option due to their small size. In this study, we report the one-step hydrothermal approach that was used to synthesize luminescent manganese doped carbon dots (Mn-Cdots) with an efficient quantum yield of 9.2% by employing green Psidium guajava L. (Guava) leaf as the precursor. High-resolution microscopy TEM was used to investigate the average particle size of Mn-Cdots, which was found to be 2.9 ± 0.045 nm. The structural properties and elemental composition of Mn-Cdots were analyzed by FTIR, XRD, EPR, and XPS spectroscopy, and the optical properties of Mn-Cdots were examined by UV-visible and fluorescent spectroscopy. Light-mediated antibacterial activity of Mn-Cdots was investigated by Gram-negative bacteria E. coli under white, blue, and yellow light. The doping effect of a minute quantity of Mn in Mn-Cdots increased the level of ROS generation in the presence of white lights compared to Cdots. Thus, Mn-Cdots might act as potent antibacterial agents.

Ag NCs as a potent antibiofilm agent against pathogenic Pseudomonas aeruginosa and Acinetobacter baumannii and drug-resistant Bacillus subtilis by affecting chemotaxis and flagellar assembly pathway genes.

Biofilm infections are highly resistant to commercial antibiotics. Therefore, developing a potent agent against such drug-resistant bacterial infections is highly desirable. Here, we synthesized positively charged silver nanoclusters (Ag NCs) with a diameter of <2 nm, which were found to be very effective antibacterial and antibiofilm agents against tetracycline-resistant Bacillus subtilis and most importantly multidrug-resistant pathogenic strains of Pseudomonas aeruginosa and Acinetobacter baumannii. Ag NCs were able to both prevent and eradicate the biofilm formation very effectively. The antibiofilm activity can be significantly increased with α-amylase and/or DNase which degrade the structural components of biofilms. The antibiofilm activity of antibiotics gets considerably lowered due to poor penetration and the acidic microenvironment of biofilms. However, the potency of antibiotics gets significantly increased when applied with Ag NCs. Finally, RNA seq-based analysis has demonstrated that the biofilm degradation was likely due to the regulation of bacterial chemotaxis and flagellar assembly pathway genes by Ag NCs.

Visible Light-Mediated Photoactivated Sulfur Quantum Dots as Heightened Antibacterial Agents.

The need for antimicrobial or antibacterial fabric has increased exponentially in recent past years, especially after the outbreak of the SARS-CoV-2 pandemic. Several studies have been conducted, and the primary focus is the development of simple, automated, performance efficient and cost-efficient fabric for disposable and frequent-use items such as personal protective materials. In this regard, we have explored the light-driven antibacterial activity of water-soluble Sdots for the first time. Sdots are a new class of non-metallic quantum dots of the nanosulfur family having a polymeric sulfur core. These Sdots exhibited excellent antibacterial activity by generating reactive oxygen species under sunlight or visible light. Under 6 h of sunlight irradiation, it was observed that >90% of the bacterial growth was inhibited in the presence of Sdots. Furthermore, low toxic Sdots were employed to develop antibacterial fabric for efficiently cleaning the bacterial infection. The prominent zone of inhibition of up to 9 mm was observed post 12 h incubation of Sdots treated fabric with E. coli in the presence of visible light. Furthermore, the SEM study confirmed the bactericidal effect of these Sdots-treated fabrics. Moreover, this study might help explore the photocatalytic disinfection application of Sdots in diverse locations of interest, Sdots-based photodynamic antimicrobial chemotherapy application, and provide an opportunity to develop Sdots as a visible light photocatalyst for organic transformations and other promising applications.

Computational Investigations on the Natural Small Molecule as an Inhibitor of Programmed Death Ligand 1 for Cancer Immunotherapy.

Several therapeutic monoclonal antibodies approved by the FDA are available against the PD-1/PD-L1 (programmed death 1/programmed death ligand 1) immune checkpoint axis, which has been an unprecedented success in cancer treatment. However, existing therapeutics against PD-L1, including small molecule inhibitors, have certain drawbacks such as high cost and drug resistance that challenge the currently available anti-PD-L1 therapy. Therefore, this study presents the screening of 32,552 compounds from the Natural Product Atlas database against PD-L1, including three steps of structure-based virtual screening followed by binding free energy to refine the ideal conformation of potent PD-L1 inhibitors. Subsequently, five natural compounds, i.e., Neoenactin B1, Actinofuranone I, Cosmosporin, Ganocapenoid A, and 3-[3-hydroxy-4-(3-methylbut-2-enyl)phenyl]-5-(4-hydroxybenzyl)-4-methyldihydrofuran-2(3H)-one, were collected based on the ADMET (absorption, distribution, metabolism, excretion, and toxicity) profiling and binding free energy (>−60 kcal/mol) for further computational investigation in comparison to co-crystallized ligand, i.e., JQT inhibitor. Based on interaction mapping, explicit 100 ns molecular dynamics simulation, and end-point binding free energy calculations, the selected natural compounds were marked for substantial stability with PD-L1 via intermolecular interactions (hydrogen and hydrophobic) with essential residues in comparison to the JQT inhibitor. Collectively, the calculated results advocate the selected natural compounds as the putative potent inhibitors of PD-L1 and, therefore, can be considered for further development of PD-L1 immune checkpoint inhibitors in cancer immunotherapy.