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Glycosylation of immune receptors and ligands, such as T cell receptor and coinhibitory molecules, regulates immune signaling activation and immune surveillance. However, how oncogenic signaling initiates glycosylation of coinhibitory molecules to induce immunosuppression remains unclear. Here we show that IL-6-activated JAK1 phosphorylates programmed death-ligand 1 (PD-L1) Tyr112, which recruits the endoplasmic reticulum-associated N-glycosyltransferase STT3A to catalyze PD-L1 glycosylation and maintain PD-L1 stability. Targeting of IL-6 by IL-6 antibody induced synergistic T cell killing effects when combined with anti-T cell immunoglobulin mucin-3 (anti-Tim-3) therapy in animal models. A positive correlation between IL-6 and PD-L1 expression was also observed in hepatocellular carcinoma patient tumor tissues. These results identify a mechanism regulating PD-L1 glycosylation initiation and suggest the combination of anti-IL-6 and anti-Tim-3 as an effective marker-guided therapeutic strategy.

Tannins are polyphenols enriched in wood, bark, roots, leaves, seeds and fruits of a variety of plants. Over the last two decades, there has been an increasing interest in understanding the biological functions of tannins and their applications as antioxidants, anticancer drugs, and food additives. Since the outbreak of the COVID-19 pandemic, much effort has been devoted to finding an expedient cure. Tannins have been put forward as having possible anti-COVID-19 properties; however, owing to the profuse nature of the structurally diverse derivatives of tannins, the tannin species in the family associated with an indication of anti-COVID-19 have been poorly defined, compounded by frequent terminology misnomers. This article reviews the tannin family in fruits and the current knowledge about the activities of the compounds with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It will aid molecular and cellular biologists in developing natural anti-viral chemicals as means of overcoming the current and future pandemics.

Tumor-secreted factors contribute to the development of a microenvironment that facilitates the escape of cancer cells from immunotherapy. In this study, we conduct a retrospective comparison of the proteins secreted by hepatocellular carcinoma (HCC) cells in responders and non-responders among a cohort of ten patients who received Nivolumab (anti-PD-1 antibody). Our findings indicate that non-responders have a high abundance of secreted RNase1, which is associated with a poor prognosis in various cancer types. Furthermore, mice implanted with HCC cells that overexpress RNase1 exhibit immunosuppressive tumor microenvironments and diminished response to anti-PD-1 therapy. RNase1 induces the polarization of macrophages towards a tumor growth-promoting phenotype through activation of the anaplastic lymphoma kinase (ALK) signaling pathway. Targeting the RNase1/ALK axis reprograms the macrophage polarization, with increased CD8 + T- and Th1- cell recruitment. Moreover, simultaneous targeting of the checkpoint protein PD-1 unleashes cytotoxic CD8 + T-cell responses. Treatment utilizing both an ALK inhibitor and an anti-PD-1 antibody exhibits enhanced tumor regression and facilitates long-term immunity. Our study elucidates the role of RNase1 in mediating tumor resistance to immunotherapy and reveals an RNase1-mediated immunosuppressive tumor microenvironment, highlighting the potential of targeting RNase1 as a promising strategy for cancer immunotherapy in HCC. Immune checkpoint inhibitors have now been approved for the treatment of advanced hepatocellular carcinoma (HCC), however only a minority of patients appear to benefit. Here the authors report that RNase1 levels predict response to nivolumab (anti-PD1) in patients with HCC and that RNase 1 overexpression correlates with an immunosuppressive tumor microenvironment in HCC preclinical models.

Malignant brain tumors consist of malignancies originated primarily within the brain and the metastatic lesions disseminated from other organs. In spite of intensive studies, malignant brain tumors remain to be a medical challenge. Patient-derived organoid (PDO) can recapitulate the biological features of the primary tumor it was derived from and has emerged as a promising drug-screening model for precision therapy. Here we show a proof-of-concept based on early clinical study entailing the organoids derived from the surgically resected tumors of 26 patients with advanced malignant brain tumors enrolled during December 2020 to October 2021. The tumors included nine glioma patients, one malignant meningioma, one primary lymphoma patient, and 15 brain metastases. The primary tumor sites of the metastases included five from the lungs, three from the breasts, two from the ovaries, two from the colon, one from the testis, one of melanoma origin, and one of chondrosarcoma. Out of the 26 tissues, 13 (50%) organoids were successfully generated with a culture time of about 2 weeks. Among these patients, three were further pursued to have the organoids derived from their tumor tissues tested for the sensitivity to different therapeutic drugs in parallel to their clinical care. Our results showed that the therapeutic effects observed by the organoid models were consistent to the responses of these patients to their treatments. Our study suggests that PDO can recapitulate patient responses in the clinic with high potential of implementation in personalized medicine of malignant brain tumors.

In late 2019, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic emerged to severely impact the global population, creating an unprecedented need for effective treatments. This study aims to investigate the potential of Scutellaria barbata D. Don (SB) as a treatment for SARS-CoV-2 infection through the inhibition of the proteases playing important functions in the infection by SARS-CoV-2. FRET assay was applied to investigate the inhibitory effects of SB on the two proteases involved in SARS-CoV-2 infection, Mpro and TMPRSS2. Additionally, to measure the potential effectiveness of SB treatment on infection inhibition, cellular models based on the Calu3 and VeroE6 cells and their TMPRSS2- expressing derivatives were assessed by viral pseudoparticles (Vpp) infection assays. The experimental approaches were conjugated with LC/MS analyses of the aqueous extracts of SB to identify the major constituent compounds, followed by a literature review to determine the potential active components of the inhibitory effects on protease activities. Our results showed that SB extracts inhibited the enzyme activities of Mpro and TMPRSS2. Furthermore, SB extracts effectively inhibited SARS-CoV-2 Vpp infection through a TMPRSS2-dependent mechanism. The aqueous extract analysis identified six major constituent compounds present in SB. Some of them have been known associated with inhibitory activities of TMPRSS2 or Mpro. Thus, SB may effectively prevent SARS-CoV-2 infection and replication through inhibiting Mpro and TMPRSS2 protease activities.

Invasion is the most prominent lethal feature of malignant cancer. However, how cell proliferation, another important feature of tumor development, is integrated with tumor invasion and the subsequent cell dissemination from primary tumors is not well understood. Proliferating cell nuclear antigen (PCNA) is essential for DNA replication in cancer cells. Loss of phosphorylation at tyrosine 211 (Y211) in PCNA (pY211-PCNA) mitigates PCNA function in proliferation, triggers replication fork arrest/collapse, which in turn sets off an anti-tumor inflammatory response, and suppresses distant metastasis. Here, we show that pY211-PCNA is important in stromal activation in tumor tissues. Loss of the phosphorylation resulted in reduced expression of mesenchymal proteins as well as tumor progenitor markers, and of the ability of invasion. Spontaneous mammary tumors that developed in mice lacking Y211 phosphorylation contained fewer tumor-initiating cells compared to tumors in wild-type mice. Our study demonstrates a novel function of PCNA as an essential factor for maintaining cancer stemness through Y211 phosphorylation.

The Coronavirus Disease 2019 (COVID-19) pandemic continues to infect people worldwide. While the vaccinated population has been increasing, the rising breakthrough infection persists in the vaccinated population. For living with the virus, the dietary guidelines to prevent virus infection are worthy of and timely to develop further. Tannic acid has been demonstrated to be an effective inhibitor of coronavirus and is under clinical trial. Here we found that two other members of the tannins family, oligomeric proanthocyanidins (OPCs) and punicalagin, are also potent inhibitors against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection with different mechanisms. OPCs and punicalagin showed inhibitory activity against omicron variants of SARS-CoV-2 infection. The water extractant of the grape seed was rich in OPCs and also exhibited the strongest inhibitory activities for viral entry of wild-type and other variants in vitro. Moreover, we evaluated the inhibitory activity of grape seed extractants (GSE) supplementation against SARS-CoV-2 viral entry in vivo and observed that serum samples from the healthy human subjects had suppressive activity against different variants of SARS-CoV-2 Vpp infection after taking GSE capsules. Our results suggest that natural tannins acted as potent inhibitors against SARS-CoV-2 infection, and GSE supplementation could serve as healthy food for infection prevention. Since it first surfaced in late 2019, the COVID-19 pandemic has had a significant impact on people’s lives. While several vaccines have been created, infections have not disappeared. This is largely due to new variants of the virus responsible for the disease (SARS-CoV-2) emerging, which current vaccines do not work as well against. Indeed, several reports suggest that protection from the omicron variant wanes as shortly as four to six months after vaccination. Therefore, other strategies are needed to reduce the risk of SARS-CoV-2 infections. In 2022, researchers discovered that tannic acid blocked two proteins that SARS-CoV-2 needs to enter and replicate inside human cells. Tannic acid is part of the tannin family, which includes natural molecules found in plant-based meals and beverages. Here, Chen et al. – including some of the researchers involved in the 2022 studies – set out to find whether two other tannins found in nature (OPCs and punicalagin) could also inhibit SARS-CoV-2. Chen et al. administered tannic acid, OPCs and punicalagin to human cells cultured in a laboratory that had been infected with SARS-CoV-2. This revealed that all three tannins suppress the activity of the same proteins required for viral entry and replication, but to varying degrees suggesting that they block SARS-CoV-2 infections via different mechanisms. The compounds were also able to inhibit different variants of the virus, including omicron, from infecting the lab-grown cells. Further experiments revealed that water extracted from seeded grapes, which contains high levels of OPCs, could also block SARS-CoV-2 entry in the cell culture system. To test this further, Chen et al. gave 18 healthy individuals capsules containing different concentrations of grape seed extract and collected samples of their serum. The serum samples suppressed entry of different variants of SARS-CoV-2 in the cell culture system, with serums from subjects that received the higher dose having the greatest effect. These findings suggest that naturally occurring tannins can suppress multiple variants of SARS-CoV-2 from entering and replicating in cells. Consuming supplements of grape seed extract could potentially reduce the risk of SARS-CoV-2 infections. However, further experiments, including clinical trials, are needed to test this possibility.

The proliferating cell nuclear antigen (PCNA) is an essential protein for DNA replication and damage repair. How its function is controlled remains an important question. Here, we show that the chromatin-bound PCNA protein is phosphorylated on Tyr 211, which is required for maintaining its function on chromatin and is dependent on the tyrosine kinase activity of EGF receptor (EGFR) in the nucleus. Phosphorylation on Tyr 211 by EGFR stabilizes chromatin-bound PCNA protein and associated functions. Consistently, increased PCNA Tyr 211 phosphorylation coincides with pronounced cell proliferation, and is better correlated with poor survival of breast cancer patients, as well as nuclear EGFR in tumours, than is the total PCNA level. These results identify a novel nuclear mechanism linking tyrosine kinase receptor function with the regulation of the PCNA sliding clamp.

Background To date, most countries lifted the restriction requirement and coexisted with SARS-CoV-2. Thus, dietary behavior for preventing SARS-CoV-2 infection becomes an interesting issue on a daily basis. Coffee consumption is connected with reduced COVID-19 risk and correlated to COVID-19 severity. However, the mechanisms of coffee for the reduction of COVID-19 risk are still unclear. Results Here, we identified that coffee can inhibit multiple variants of the SARS-CoV-2 infection by restraining the binding of the SARS-CoV-2 spike protein to human angiotensin-converting enzyme 2 (ACE2), and reducing transmembrane serine protease 2 (TMPRSS2) and cathepsin L (CTSL) activity. Then, we used the method of \"Here\" (HRMS-exploring-recombination-examining) and found that isochlorogenic acid A, B, and C of coffee ingredients showed their potential to inhibit SARS-CoV-2 infection (inhibitory efficiency 43–54%). In addition, decaffeinated coffee still preserves inhibitory activity against SARS-CoV-2. Finally, in a human trial of 64 subjects, we identified that coffee consumption (approximately 1–2 cups/day) is sufficient to inhibit infection of multiple variants of SARS-CoV-2 entry, suggesting coffee could be a dietary strategy to prevent SARS-CoV2 infection. Conclusions This study verified moderate coffee consumption, including decaffeination, can provide a new guideline for the prevention of SARS-CoV-2. Based on the results, we also suggest a coffee-drinking plan for people to prevent infection in the post-COVID-19 era.

PD-L1 is highly glycosylated, and this post-translational modification is critical for PD-L1 protein stability and function.6,7 PD-L1 glycosylation is regulated by various oncogenic signalling pathways such as the epidermal growth factor receptor (EGFR) pathway, which inhibits phosphorylation of extracellular domain of PD-L1 by GSK3β.8 The phosphorylation by GSK3β hinders PD-L1 from its glycosylation, leading to its ubiquitin-mediated proteasome degradation.6 In addition, another study also indicates that glycosylation of PD-L1 interferes PD-L1 protein detection by some traditional PD-L1 antibodies that are designed to recognize its polypeptide antigens.9 Human cancer cell lines or tissues section of several cancer types treated with a glycosidase have the higher signals of PD-L1 in IHC staining than that of the untreated one, indicating that removal of N-linked glycosylation of PD-L1 enhances binding of traditional anti-PD-L1 mAb to PD-L1.9 Thus, it was proposed that inconsistent observations between PD-L1 IHC staining and clinical responses may be due to the failure of accurate PD-L1 detection in tumour tissues complicated by its glycosylation. [...]several studies have supported the notion that deglycosylation of tumour tissues improves predictive ability of PD-L1 expression in tumours as a marker for anti-PD-1/PD-L1 therapy.10–12 It is worth noting that in 2019, based on the IMpassion130 trial, the U.S. FDA granted accelerated approval to atezolizumab, a humanized anti-PD-L1 monoclonal antibody, in combination with nab-paclitaxel for treatment of advanced triple negative breast cancer (TNBC) patients, whose tumours show PD-L1 positivity by IHC tests from immune cells.13 However, in the following randomized Phase III clinical trial (IMpassion 131), the combination of atezolizumab and paclitaxel did not show significant clinical benefits compared to paclitaxel alone,14 and the atezolizumab TNBC indication was withdrawn voluntarily by Roche in 2021. [...]a larger cohort is warrant to develop further. [...]PD-L1 detection after deglycosylation by glycosidase pre-treatment may improve the predictive value of PD-L1 expression as a marker to select patients for ICI treatment (Figure 1).