Advances in Engineering Circular RNA Vaccines.

Engineered circular RNAs (circRNAs) are a class of single-stranded RNAs with head-to-tail covalently linked structures that integrate open reading frames (ORFs) and internal ribosome entry sites (IRESs) with the function of coding and expressing proteins. Compared to mRNA vaccines, circRNA vaccines offer a more improved method that is safe, stable, and simple to manufacture. With the rapid revelation of the biological functions of circRNA and the success of Severe Acute Respiratory Coronavirus Type II (SARS-CoV-2) mRNA vaccines, biopharmaceutical companies and researchers around the globe are attempting to develop more stable circRNA vaccines for illness prevention and treatment. Nevertheless, research on circRNA vaccines is still in its infancy, and more work and assessment are needed for their synthesis, delivery, and use. In this review, based on the current understanding of the molecular biological properties and immunotherapeutic mechanisms of circRNA, we summarize the current preparation methods of circRNA vaccines, including design, synthesis, purification, and identification. We discuss their delivery strategies and summarize the challenges facing the clinical application of circRNAs to provide references for circRNA vaccine-related research.

Recent progress of polymeric microneedle-assisted long-acting transdermal drug delivery.

Microneedle (MN)-assisted drug delivery technology has gained increasing attention over the past two decades. Its advantages of self-management and being minimally invasive could allow this technology to be an alternative to hypodermic needles. MNs can penetrate the stratum corneum and deliver active ingredients to the body through the dermal tissue in a controlled and sustained release. Long-acting polymeric MNs can reduce administration frequency to improve patient compliance and therapeutic outcomes, especially in the management of chronic diseases. In addition, long-acting MNs could avoid gastrointestinal reactions and reduce side effects, which has potential value for clinical application. In this paper, advances in design strategies and applications of long-acting polymeric MNs are reviewed. We also discuss the challenges in scale manufacture and regulations of polymeric MN systems. These two aspects will accelerate the effective clinical translation of MN products.

Regulatory mechanism underlying liver X receptor effects on the tumor microenvironment, inflammation and tumorigenesis.

INTRODUCTION: Liver X receptors (LXRs) have emerged as novel targets for tumor treatment. LXRs within the tumor microenvironment show the capacity to impact tumorigenesis and tumor development by regulating the infiltration of immune cells and release of cytokines to moderate inflammation. AREAS COVERED: In this review, we present a systematic description of recent progress in understanding the impact of LXRs on the tumor microenvironment and tumorigenesis. We also summarize the antitumor effects mediated by LXRs via their regulation of cytokine expression. Additionally, we discuss the limitations of LXR research in tumor studies to date. EXPERT OPINION: Previous studies have demonstrated abnormal LXR expression in tumor tissues, and activation of LXRs has been shown to inhibit tumorigenesis and promote apoptosis in tumor cells. However, LXRs can also affect tumorigenesis by regulating immune cell functions within the tumor immune microenvironment. By summarizing the impact of LXRs on immune cells, we provide new insights into the multifaceted nature of LXRs as antitumor targets.

Insect transient receptor potential vanilloid channels as potential targets of insecticides.

Chordotonal organs are miniature sensory organs present in insects. Chordotonal organs depend on transient receptor potential (TRP) channels. Transient receptor potential vanilloid (TRPV) channels are the only TRPs identified that can act as targets of insecticides. By binding with TRPV channels, insecticides targeting the chordotonal organs trigger the inflow of calcium ions, resulting in abnormal function of the chordotonal organ to achieve the goal of eliminating pests. TRPV channels are highly expressed in various developmental stages and tissue parts of insects and play an important role in the whole life history of insects. In this review, we will discuss the structure and types of TRPV channels as well as their genetic relationships in different species. We also systematically reviewed the recent progress of TRPV channels as insecticide targets, demonstrating that TRPV channels can be used as the target of new high-efficiency insecticides.

Shikonin triggers GSDME-mediated pyroptosis in tumours by regulating autophagy via the ROS-MAPK14/p38α axis.

BACKGROUND: Shikonin (SK), a botanical drug extracted from Lithospermum erythrorhizon, has been shown to inhibit tumour growth through apoptosis and necrosis. However, whether SK induces pyroptosis in cancer cells is still unknown. PURPOSE: This study aims to investigated the mechanisms of SK-induced pyroptosis in tumour cells and mice. METHODS: In vivo and in vitro methods were used in this study. Cell deaths were analysed by LDH and CCK-8 assay and western blotting. To investigated the signalling pathway of SK-induced pyroptosis, various genes expressions were supressed by shRNA or inhibitors. High-sensitivity mass spectrometry assay was used to identified potential factors that regulate GSDME-mediated pyroptosis. Finally, a mouse model was used to investigate the effect of SK administration on tumour growth in vivo. RESULTS: The activation of BAX/caspase-3 signalling was essential for GSDME-mediated pyroptosis by SK. Mechanistically, the intracellular reactive oxygen species (ROS) generation induced by SK treatment initiated GSDME-dependant pyroptosis. SK stimulation induced protective autophagy in a ROS-dependant manner, and repressed autophagy significantly enhanced SK-induced pyroptosis. Moreover, MAPK14/p38α, a ROS sensor, modulated SK-induced autophagy and ultimately affected GSDME-dependant pyroptosis. CONCLUSION: Here, for the first time we demonstrated that SK treatment induced GSDME-dependant pyroptosis in tumour cells. Our results demonstrated that SK initiates ROS signalling to drive pyroptosis in cancer cells.

Effects of tolfenpyrad exposure on development and response mechanism in the silkworm, Bombyx mori.

Tolfenpyrad is a broad spectrum of insecticide that can effectively kill different types of pests, including Lepidoptera. However, due to improper use, the adverse effects of tolfenpyrad on beneficial or economic insects have not been well studied. In this study, we systematically investigated the toxic effect of sublethal tolfenpyrad on silkworms. Sublethal tolfenpyrad exposure can affect the body weight, developments days, cocooning rate, eclosion rate and pupation rate. To further study the response mechanism of silkworms to tolfenpyrad stimulation, we compared the different expression genes by transcriptome sequencing and verified them by qRT-PCR. We found that significant changes in the genes expression was involved in xenobiotics biodegradation and metabolism, immune system and digestive system after tolfenpyrad treatment. To further investigate the possible mechanisms by which intestinal microbia in the response to tolfenpyrad, we analysed the microbia changes in the midgut of silkworms by 16S rRNA gene sequencing. The results showed that the relative abundances of Enterobacter and Staphylococcus were increased whereas the Tyzzerella and Methylobacterium-Methylorubrum were decreased after tolfenpyrad stimulation. Taken together, these results indicated that low concentration of tolfenpyrad affect the growth and development of silkworms. Silkworms respond to the toxicity of tolfenpyrad by inducing immune and detoxification-related gene expression or altering microbial composition in the midgut.

Molecular mechanism of shikonin inhibiting tumor growth and potential application in cancer treatment.

Shikonin is one of the major bioactive components of Lithospermum erythrorhizon. It has a good killing effect in a variety of tumor cells. Its antitumor effect involves multiple targets and pathways and has received extensive attention and study in recent years. In this review, we systematically review recent progress in determining the antitumor mechanism of shikonin and its derivatives, specifically their induction of reactive oxygen species production, inhibition of EGFR and PI3K/AKT signaling pathway activation, inhibition of angiogenesis and induction of apoptosis and necroptosis. We also discuss the application of nanoparticles loaded with shikonin in the targeted therapy of various cancers. Finally, we suggest new strategies for the clinical application of shikonin and its derivatives.

Role of pyroptosis in cancer cells and clinical applications.

Chemotherapy drugs usually inhibit tumor cell growth through the apoptosis pathway. However, tumor cells become resistant to chemotherapy drugs by evading apoptosis. It is necessary to find new ways to inhibit tumor growth through other types of death. Pyroptosis is a recently identified inflammatory cell death that plays an important role in a variety of diseases, including cancer. In this review, we will systematically review recent progress in the pyroptosis signaling pathway, the role of inflammasomes in cancer in the context of pyroptosis, the role of gasdermin proteins in cancer and the role of pyroptosis in tumor immunity. We will also discuss the application of the pyroptosis pathway in clinical studies. Finally, we hope to provide new strategies for pyroptosis in the clinic.

Research progress on tumour­associated macrophages in gastric cancer (Review).

Tumour­associated macrophages (TAMs) are immune cells that are present in large numbers in the tumour immune microenvironment. TAMs are important for the occurrence, development, invasion, metastasis and immune escape of tumours. TAMs have become a novel therapeutic target and prognostic indicator in the individualised treatment of patients. Studies have reported that the number of TAMs can predict the size, stage and metastasis of gastric cancer. Therefore, in­depth examination of TAMs may be important for high­risk screening, early diagnosis and prognostic judgment of patients with gastric cancer. The present review examined the research progress of TAMs in gastric cancer on the basis of previous literature studies. Moreover, this review systematically evaluated the three major aspects of the differentiation of macrophages, the tumour­promoting mechanism of TAMs in gastric cancer and the relationship between TAMs and treatment of gastric cancer. Finally, this review aimed to provide a reference for investigating the prognostic indicators and treatment targets of patients with gastric cancer.

Tumor-associated macrophages induce PD-L1 expression in gastric cancer cells through IL-6 and TNF-ɑ signaling.

PD-1/PD-L1 immune checkpoint blockade therapy has been widely used for the clinical treatment of cancer. However, recent clinical trials have shown that only a small proportion of cancer patients respond to PD1/PD-L1 immunotherapy. The tumor immune microenvironment plays an important regulatory role in PD1/PD-L1 immunotherapy. Macrophages are one of the most important immune cells in the tumor immune microenvironment. In this study, we found a high correlation between macrophage infiltration and PD-L1 expression in gastric cancer (GC) specimens. Further study revealed that infiltrated macrophages released the proinflammatory cytokines TNF-ɑ and IL-6, which induced PD-L1 expression in tumor cells. The release of TNF-ɑ and IL-6 activated the NF-kB and STAT3 signaling pathway to regulate PD-L1 expression. TNF-α, p-65 and STAT3 expression in cancer patients has prognostic value in stomach adenocarcinoma. Furthermore, infiltrated macrophages can also promote GC cell proliferation by inducing PD-L1 expression in GC cells. Taken together, our results suggest that macrophages play a dual role in regulating the expression of PD-L1 in tumor cells. On the one hand, macrophages induce PD-L1 expression in tumor cells, helping tumor cells escape cytotoxic T cell killing; on the other hand, they can promote the proliferation of tumor cells by regulating the expression of PD-L1.

A Novel Prognostic Marker Systemic Inflammation Response Index (SIRI) for Operable Cervical Cancer Patients.

It has been confirmed that the systemic inflammation response index (SIRI) based on peripheral blood neutrophil, monocyte and lymphocyte counts can be used for the prognostication of patients with various malignant tumors. However, the prognostic value of SIRI in cervical cancer patients has not yet been reported. This study found that a higher SIRI was related to lymphovascular invasion and was also significantly associated with FIGO stage, radiotherapy, neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), and monocyte/lymphocyte ratio (MLR) but not related to other clinical and pathological parameters. According to the Kaplan-Meier survival analysis, a high SIRI was associated with the poor prognosis of cervical cancer patients in the primary and validation groups. SIRI, NLR, PLR, and MLR can all be used to determine the prognosis of patients with operable cervical cancer. Moreover, it was confirmed that only SIRI was an independent prognostic factor for patients with operable cervical cancer. The same result was obtained in the propensity score matching (PSM) analysis. In the ROC curve analysis, SIRI was more accurate in predicting the prognosis of cervical cancer patients. Then, a nomogram was established based on SIRI, FIGO stage and lymphovascular invasion, which could determine the prognosis of cervical cancer patients more accurately than FIGO stage. The validation cohort showed the same results. In addition, the changes in SIRI relative to the baseline value at 4-8 weeks after surgery were closely related to the survival of cervical cancer patients. Compared with those with unchanged SIRI (absolute value of variation <25%), cervical cancer patients with an increase in SIRI > 75% had worse OS (P < 0.001), while patients with a decrease in SIRI > 75% had a better prognosis (P < 0.001). SIRI can serve as a new independent prognostic index and a potential marker for therapeutic response monitoring in patients with curable cervical cancer. Compared with the traditional FIGO staging system, the nomogram integrating SIRI can predict the survival of cervical cancer patients more objectively and reliably after radical surgery.

Regulation of PD-L1 expression in cancer and clinical implications in immunotherapy.

PD-1/PD-L1 immune checkpoint blockade therapy has become an effective method for the treatment of cancers in the clinic. It has great clinical advantages and therapeutic effects in the treatment of various cancers. However, a considerable number of cancer patients currently have relatively low response rates and drug resistance to PD-1/PD-L1 immunotherapy. Therefore, an in-depth understanding of the regulatory mechanism of PD-L1 expression in tumor cells will provide new insights into PD-1/PD-L1 immunotherapy. This review will systematically review the regulatory mechanisms of PD-L1 including genomic amplification, epigenetic regulation, transcriptional regulation, translational regulation and posttranslational modification. We will also discuss PD-L1 expression regulation in clinical applications. Finally, we hope to provide new routes for PD-1/PD-L1 immunotherapy in the clinic.

Analysis of candidate biomarkers and related transcription factors involved in the development and restoration of stress-induced gastric ulcer by transcriptomics.

Stress-induced gastric ulcer is one of the common complications affecting patients after trauma, mainly leading to gastrointestinal bleeding and perforation, and severe cases may be life-threatening. However, the molecular mechanism of stress-induced gastric ulcer remains unclear. In the present study, RNA-sequencing was performed on gastric tissues of normal rats (C), stress-induced gastric ulcer rats (T0), and rats recovered from gastric ulcer for 3 days (T3), and bioinformatics analysis was performed to determine changes in gene expression and biological pathways. The protein-protein interaction (PPI) networks of differentially expressed genes (DEGs) were constructed by STRING and visualized by the Cytoscape software. The associated transcriptional factor (TFs)-gene regulatory network of the hub DEGs was also constructed. Pairwise comparisons obtained 103 (T0_C), 127 (T3_T0), and 13 (T3_C) DEGs, respectively. Gene ontology (GO) enrichment analysis indicated DEGs in T0_C and T3_T0 were significantly enriched in response to oxygen-containing compound, response to organic substance, and response to external stimulus. Pathway analysis suggested that DEGs were enriched in TNF signaling pathway, PPAR signaling pathway, apoptosis, and IL-17 signaling pathway. Seven hub genes (Fos, Jun, Nfkbia, Dusp1, Pim3, Junb, and Fosb) were obtained from the PPI networks of T0_C and T3_T0. Key TFs with close interactions, such as Fos, Jun, Nfkbia, Junb, Egr1, and Fosb, were screened This study used RNA-sequencing and bioinformatics analysis to screen out genes associated with gastric ulcer, which can help reveal the molecular mechanism of gastric ulcer development and restoration, and provide reference for the treatment of human gastric ulcers.

Liver X receptor activation reduces gastric cancer cell proliferation by suppressing Wnt signalling via LXRß relocalization.

Liver X receptors (LXRs) are involved in various diseases associated with lipid disorders, and in regulating cancer cell proliferation. However, the underlying molecular mechanisms, especially those in gastric cancer (GC) remain to be clarified. In this study, immunohistochemistry analysis revealed that LXRß was mainly expressed in GC tissue, with less expression in adjacent normal tissues. The LXRß agonist T0901317 efficiently suppressed the proliferation and colony formation of various GC cell lines. We further showed that LXRß translocated from the cytoplasm to the nucleus when activated by T0901317. LXRß nuclear localization suppressed the activation of Wnt signalling and decreased the expression of target genes such as MYC, BMP4, and MMP7 through binding to their promoters. Moreover, we demonstrated that the LXR agonist efficiently suppressed GC tumour growth in a nude mouse xenograft model. Taken together, these results revealed that LXRß agonist inhibited GC cells proliferation by suppressing Wnt signalling via LXRß relocalization. The results strongly suggest that LXRß could be a promising target in GC therapy.

Immunogenic cell death in anticancer chemotherapy and its impact on clinical studies.

The traditional view holds that apoptosis is non-immunogenic and does not induce an inflammatory response. However, recent studies have suggested that certain chemotherapeutic drugs that induce tumor cell apoptosis can induce immunogenic cell death (ICD) in cancer cells. This process is characterized by not only up-regulation of a series of signaling molecules in cancer cells, including expose of calreticulin (CRT), secretion of adenosine triphosphate (ATP) and release of high mobility group box 1 (HMGB1). In this review, we summarize recent progress in identifying and classifying ICD inducers; concepts and molecular mechanisms of ICD; and the impact and potential applications of ICD in clinical studies. We also discuss the contributions of ICD inducers in combination with other anticancer drugs in clinical applications.

Treatment of colon cancer with liver X receptor agonists induces immunogenic cell death.

Liver X receptor (LXR) agonists inhibit various types of tumor growth and have been applied to preclinical research. In colon cancer cells, LXR agonists induce pyroptotic cell death through the predominant cytoplasmic localisation of LXRß. In the present study, we determined whether tumor cell death induced by LXR agonists in colon cancer cells could elicit immunogenic cell death (ICD). LXR agonist-treated-colon cancer cells exhibited translocation of calreticulin (CRT) and release of HMGB1 and ATP into the medium. Expression levels of CRT and HMGB1 were also increased in T0901317-treated Balb/c mice. Furthermore, compared with control mice, mice vaccinated with T0901317-treated CT26 cells showed reduced tumor volumes and protection against a challenge with live tumor cells. Inhibition of CRT or HMGB1 expression in CT26 cells abolished this protection in Balb/c mice. In conclusion, the LXR agonist T0901317 induces ICD in colon cancer cells. CRT exposure and HMGB1 release play a critical role in the immunogenicity of this treatment.

Overexpression of c-Myc enhances recombinant protein production in High Five cells after baculovirus infection.

Due to their numerous advantages, baculovirus expression vector systems (BEVS) have been widely used to express recombinant proteins for different purposes. Different strategies have been adopted to increase recombinant protein production. In this study, we transiently or stably expressed mouse c-Myc in High Five cells using a commercial pIB/V5 vector. Under the control of the OpIE2 promoter, this vector could enhance recombinant protein production. We found that transient expression of c-Myc in High Five cells improved recombinant protein production. Furthermore, we established two stable cell lines, High Five-c-Myc #1 and High Five-c-Myc #2, that stably expressed mouse c-Myc. We further found that the expression level of the recombinant protein was increased in these stable cell lines compared to control cell lines. These data indicate that overexpressing c-Myc in cells is a promising way to improve recombinant protein production in BEVS.

Predictive relevance of PD-L1 expression with pre-existing TILs in gastric cancer.

Expression of programmed cell death receptor ligand 1 (PD-L1) has been shown to be up-regulated in some gastric cancer patients and to correlate with the density of tumour infiltrating lymphocytes (TILs). However, conflicting results have been reported regarding TILs and the expression of PD-L1 as a prognostic marker for gastric cancer. We investigated the correlation of PD-L1 and TILs expression with clinicpathological characteristics in 105 well characterized gastric cancer patients. PD-L1 expression and CD3+ and CD8+ TILs were evaluated by fluorescent multiplex immunohistochemistry (mIHC) analysis. PD-L1 positive staining on tumour cells was observed in 35% cases and 48% cases showed PD-L1 expression on immune cells. Up-regulated PD-L1 expression on tumour cells and immune cells was associated with high density of pre-existing tumour infiltrating CD3+ and CD8+. In additional, more than 70% tumor infiltrating CD3+ cells were CD3+CD8+ cells. More than 60% PD-L1+ immune cells were PD-L1+CD3+CD8+ cells. PD-L1 expression in tumour cells was associated with poor prognosis and high density CD3+ and CD8+ TILs indicated improved overall survival in gastric cancer patients. Increased PD-L1 expression with low density CD3+ and CD8+ TILs had the shortest overall survival. In accordingly, PD-L1 absence with high density CD3+ and CD8+ TILs indicated the best prognosis. Combination of PD-L1 with pre-existing TILs may be more precise than PD-L1 alone for predicting survival in gastric cancer.

Liver X receptors as potential targets for cancer therapeutics.

Liver X receptors (LXRs) are important members of the nuclear receptor family that were originally determined to function in cholesterol transport and the regulation of immune responses. Synthetic LXR ligands have been developed to treat various diseases including diabetes, Alzheimer's disease and atherosclerosis. Previous studies have suggested that LXRs are also involved in numerous types of cancer and are therefore potential targets for cancer therapeutics. The present review summarizes LXR ligands and their mechanisms of action, the effects of LXRs in different types of cancer and their potential applications in clinical treatment. Together, the studies discussed in the present review indicate that LXRs may be potential targets for cancer therapeutics.

Comparative proteomic analysis of rats subjected to water immersion and restraint stress as an insight into gastric ulcers.

In the present study, comparative proteomic analysis was performed in rats subjected to water immersion­restraint stress (WRS). A total of 26 proteins were differentially expressed and identified using matrix­assisted laser desorption/ionization time of flight mass spectrometry. Among the 26 differentially expressed protein spots identified, 13 proteins were significantly upregulated under WRS, including pyruvate kinase and calreticulin, which may be closely associated with energy metabolism. In addition, 12 proteins were downregulated under WRS, including hemoglobin subunit ß­2 and keratin type II cytoskeletal 8, which may be important in protein metabolism and cell death. Gene Ontology analysis revealed the cellular distribution, molecular function and biological processes of the identified proteins. The mRNA levels of certain differentially expressed proteins were analyzed using fluorescence quantitative polymerase chain reaction analysis. The results of the present study aimed to offer insights into proteins, which are differentially expressed in gastric ulcers in stress, and provide theoretical evidence of a radical cure for gastric ulcers in humans.