Chrysin inhibits hepatocellular carcinoma progression through suppressing programmed death ligand 1 expression

Harnessing the capacity of phytochemicals to enhance immune checkpoint inhibitor therapy of cancers: A focus on brain malignancies

Brain cancers, particularly glioblastoma multiforme (GBM), are challenging health issues with frequent unmet aspects. Today, discovering safe and effective therapeutic modalities for brain tumors is among the top research interests. Immunotherapy is an emerging area of investigation in cancer treatment. Since immune checkpoints play fundamental roles in repressing anti-cancer immunity, diverse immune checkpoint inhibitors (ICIs) have been developed, and some monoclonal antibodies have been approved clinically for particular cancers; nevertheless, there are significant concerns regarding their efficacy and safety in brain tumors. Among the various tools to modify the immune checkpoints, phytochemicals show good effectiveness and excellent safety, making them suitable candidates for developing better ICIs. Phytochemicals regulate multiple immunological checkpoint-related signaling pathways in cancer biology; however, their efficacy for clinical cancer immunotherapy remains to be established. Here, we discussed the involvement of immune checkpoints in cancer pathology and summarized recent advancements in applying phytochemicals in modulating immune checkpoints in brain tumors to highlight the state-of-the-art and give constructive prospects for future research.

Progress in small-molecule inhibitors targeting PD-L1

PD-L1 is a transmembrane protein overexpressed by tumor cells. It binds to PD-1 on the surface of T-cells, suppresses T-cell activity and hinders the immune response against cancer. Clinically, several monoclonal antibodies targeting PD-1/PD-L1 have achieved significant success in cancer immunotherapy. Nevertheless, their disadvantages, such as unchecked immune responses, high cost and long half-life, stimulated pharmacologists to develop small-molecule inhibitors targeting PD-1/PD-L1. After a batch of excellent inhibitors with a biphenyl core structure were firstly reported by BMS, more and more researchers focused on small-molecule inhibitors targeting PD-L1 rather than PD-1. Numerous small-molecule inhibitors were extensively designed and synthesized in the past few years. In this paper, the structural characteristics of PD-L1 and complexes of PD-L1 with its inhibitors are elaborated and small molecule inhibitors developed in the last decade are summarized as well. This paper aims to provide insights into further designing and synthesis of small molecule inhibitors targeting PD-L1.

Oncolytic Peptide-Nanoplatform Drives Oncoimmune Response and Reverses Adenosine-Induced Immunosuppressive Tumor Microenvironment

The application of oncolytic peptides has become a powerful approach to induce complete and long-lasting remission in multiple types of carcinomas, as affirmed by the appearance of tumor-associated antigens and adenosine triphosphate (ATP) in large quantities, which jumpstarts the cancer-immunity cycle. However, the ATP breakdown product adenosine is a significant contributor to forming the immunosuppressive tumor microenvironment, which substantially weakens peptide-driven oncolytic immunotherapy. In this study, a lipid-coated micelle (CA@TLM) loaded with a stapled oncolytic peptide (PalAno) and an adenosine 2A receptor (A2AR) inhibitor (CPI-444) is devised to enact tumor-targeted oncolytic immunotherapy and to overcome adenosine-mediated immune suppression simultaneously. The CA@TLM micelle accumulates in tumors with high efficiency, and the acidic tumor microenvironment prompts the rapid release of PalAno and CPI-444. Subsequently, PalAno induces swift membrane lysis of tumor cells and the release of antigenic materials. Meanwhile, CPI-444 blocks the activation of the immunosuppressive adenosine-A2AR signaling pathway. This combined approach exhibits pronounced synergy at stalling tumor growth and metastasis in animal models for triple-negative breast cancer and melanoma, providing a novel strategy for enhanced oncolytic immunotherapy.

Prognostic biomarker DARS2 correlated with immune infiltrates in bladder tumor

Background

DARS2 is a pivotal member of the Aminoacyl-tRNA synthetases family that is critical for regulating protein translation. However, the biological role of DARS2 in bladder cancer remains elusive.

Methods

We analyzed the correlation between DARS2 expression and prognosis, tumor stage, and immune infiltration in bladder cancer using The Cancer Genome Atlas (TCGA) database. We validated findings in clinical samples from The First Affiliated Hospital of Nanchang University and explored the biological functions of DARS2 using cell and animal models.

Results

We found DARS2 to be upregulated in bladder cancer, associated with tumor progression and poor prognosis. Immune infiltration analysis suggested that DARS2 may facilitate immune evasion by modulating PD-L1. Cell and animal experiments validated that DARS2 knockdown and overexpress can inhibit or increase cancer cell proliferation, metastasis, tumorigenesis, immune escape, and PD-L1 levels.

Conclusions

Our study reveals DARS2 as a potential prognostic biomarker and immunotherapy target in BLCA.

Polyphenol Supplementation Enhances the Efficacy of PD-1/PD-L1 Inhibitors Against Cancer: A Meta-Analysis of Animal Studies

BACKGROUND

This study performed a meta-analysis to evaluate the combined effects of polyphenols and anti-programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1) inhibitors.

METHODS

Relevant studies were collected from electronic databases. Standardized mean differences (SMDs) or hazard ratio (HR) was calculated by Stata 15.0 software.

RESULTS

Sixteen preclinical studies were included. The overall meta-analysis showed that, compared to anti-PD-1/PD-L1 alone, polyphenol combined therapy significantly reduced the tumor volume (SMD = -3.28), weight (SMD = -2.18), number (SMD = -2.17), and prolonged the survival (HR = 0.45) of mice (all P < 0.001). Pooled analysis of mechanism studies indicated polyphenol combined therapy could increase the number of cytotoxic CD8+ T cells (SMD = 3.88; P < 0.001), IFN-γ+ CD8+ T cells (SMD = 2.38; P < 0.001), decrease the number of myeloid-derived suppressor cells (SMD = -2.52; P = 0.044) and Treg cells (SMD = -4.00; P = 0.004) and suppress PD-L1 expression in tumors (SMD = -13.41; P < 0.001). Subgroup analyses demonstrated curcuminoids, flavonoids, and stilbene changed the tumor volume, the percentage of CD8+ T cells, IFN-γ+CD8+ T cells, and PD-L1 expression.

CONCLUSION

Polyphenol supplementation may be a promising combined strategy for patients with poor response to anti-PD-1/PD-L1 monotherapy.

The current status and future of PD-L1 in liver cancer

The application of immunotherapy in tumor, especially immune checkpoint inhibitors (ICIs), has played an important role in the treatment of advanced unresectable liver cancer. However, the efficacy of ICIs varies greatly among different patients, which has aroused people's attention to the regulatory mechanism of programmed death ligand-1 (PD-L1) in the immune escape of liver cancer. PD-L1 is regulated by multiple levels and signaling pathways in hepatocellular carcinoma (HCC), including gene variation, epigenetic inheritance, transcriptional regulation, post-transcriptional regulation, and post-translational modification. More studies have also found that the high expression of PD-L1 may be the main factor affecting the immunotherapy of liver cancer. However, what is the difference of PD-L1 expressed by different types of cells in the microenvironment of HCC, and which type of cells expressed PD-L1 determines the effect of tumor immunotherapy remains unclear. Therefore, clarifying the regulatory mechanism of PD-L1 in liver cancer can provide more basis for liver cancer immunotherapy and combined immune treatment strategy. In addition to its well-known role in immune regulation, PD-L1 also plays a role in regulating cancer cell proliferation and promoting drug resistance of tumor cells, which will be reviewed in this paper. In addition, we also summarized the natural products and drugs that regulated the expression of PD-L1 in HCC.

Paeoniflorin inhibits hepatocellular carcinoma growth by reducing PD-L1 expression

Abnormal expression of programmed death-ligand 1 (PD-L1) on cancer cells contributes to immune escape in hepatocellular carcinoma (HCC). Paeoniflorin has been shown to inhibit the growth of HCC; however, whether its inhibitory effect involves reducing PD-L1 expression on HCC cells remains unknown. We investigated the antitumor effects of paeoniflorin and its potential regulatory mechanisms in HCC. The effects of paeoniflorin on tumor growth and tumor immunity were determined in H22-xenografted mice and DEN-induced HCC rats. Small interfering RNA against suppressor of cytokine signaling 3 (SOCS3) was transfected into HepG2 cells to verify the effect of paeoniflorin on the SOCS3/signal transducer and activator of transcription 3 (STAT3)/PD-L1signaling pathway. The levels of SOCS3/STAT3/PD-L1 signaling pathway-related mRNAs and proteins were determined by real time-polymerase chain reaction and western blotting, respectively. Interleukin-2 (IL-2), interferon-γ (IFN-γ), granzyme B (GrB), and perforin 1 (PRF1) levels were detected in an H22 and mouse T cell co-culture system. Paeoniflorin can trigger T cell-mediated anti-tumor immune responses by increasing CD8+ T cell counts in tumor tissues, thereby inhibiting tumor growth. Moreover, paeoniflorin increased IL-2, IFN-γ, GrB, and PRF1 levels in the co-culture system. PD-L1 expression was suppressed by paeoniflorin, and this effect was mediated by the SOCS3/STAT3 signaling pathway. Paeoniflorin might thus act via enhancing SOCS3 to inhibit STAT3/PD-L1 signaling and subsequently restore T cell sensitivity to kill tumor cells. Our findings provide novel insights into the anticancer effects of paeoniflorin.

Marsdenia tenacissima enhances immune response of tumor infiltrating T lymphocytes to colorectal cancer

Introduction

Tumor-infiltrating T lymphocytes in the tumor microenvironment are critical factors influencing the prognosis and chemotherapy outcomes. As a Chinese herbal medicine, Marsdenia tenacissima extract (MTE) has been widely used to treat cancer in China. Its immunoregulatory effects on tumor-associated macrophages is well known, but whether it regulates tumor-infiltrating T-cell functions remains unclear.

Method

We collected 17 tumor samples from MTE-administered colorectal cancer patients, 13 of which showed upregulation of CD3+/CD8+ tumor-infiltrating T cells. Further in vitro and in vivo experiments were performed to investigate the regulatory effects of MTE on tumor-infiltrating T cells and immune escape of tumors.

Results

Under single and co-culture conditions, MTE inhibited TGF-β1 and PD-L1 expression in the colorectal cancer (CRC) cell lines HCT116 and LoVo. In Jurkat cells, MTE inhibited FOXP3 and IL-10 expression, increased IL-2 expression, but had no effect on PD-1 expression. These findings were confirmed in vitro using subcutaneous and colitis-associated CRC mouse models. MTE also increased the density of CD3+/CD8+ tumor-infiltrating T cells and exhibited considerable tumor-suppressive effects in these two tumor mouse models.

Conclusions

Our findings suggested that MTE inhibits the immune escape of cancer cells, a precipitating factor increasing the immune response of T lymphocytes.

In Vitro Digestion of Peanut Skin Releases Bioactive Compounds and Increases Cancer Cell Toxicity

Peanut skin is a rich source of bioactive compounds which may be able to reduce the risk factors associated with metabolic syndromes. This study aimed to characterize bio-compounds from peanut skin (Arachis hypogaea) and their bioactivity (antioxidant activity, inhibition of lipase, and carbohydrase enzymes) and to evaluate their anti-proliferative properties in colorectal cancer cells (HCT116) upon in vitro digestion. Peanut skin was digested in two sequential phases, and the final content, named phase-1 (P1) and phase-2 (P2) extracts, was evaluated. Several bioactive compounds were positively identified and quantified by liquid chromatography, including quinic acid, released especially after in vitro digestion. The total phenolic content and, regardless of the method, the antioxidant activity of P1 was higher than P2. P1 also showed a lower enzyme inhibitory concentration IC₅₀ than P2, lipase, and α-glucosidase. For cell viability in HCT116 cells, lower concentrations of P1 were found for IC₅₀ compared to P2. In conclusion, bioactive compounds were released mainly during the first phase of the in vitro digestion. The digested samples presented antioxidant activity, enzyme inhibitory activity, and cancer cell cytotoxicity, especially those from the P1 extract. The potential applications of such a by-product in human health are reported.

IRF-1-inhibited lncRNA XIST regulated the osteogenic differentiation via miR-450b/FBXW7 axis

Osteoporosis influences life quality among elder people. Osteoblast dysfunction could cause the occurrence of osteoporosis. LncRNA XIST are involved in the progression of osteoporosis. However, the correlation between IRF-1 and XIST in osteogenic differentiation remains unclear. In the study, Clinical samples were collected for the analysis of XIST level. mRNA and protein levels were detected by RT-qPCR and western blot, respectively. H&E staining was performed to observe the histological changes in mice. Alizarin Red Staining was applied to assess the calcium deposits in hBMSCs. Meanwhile, the relation among XIST, miR-450b and FBXW7 was investigated by dual luciferase assay and ChIP. In vivo model was constructed to assess the impact of XIST in osteoporosis. XIST was found to be upregulated in osteoporosis, and XIST overexpression could inhibit the osteogenic differentiation in hBMSCs. IRF-1 could transcriptionally inhibit the expression of XIST, and XIST could inhibit osteogenic differentiation through binding with miR-450b in hBMSCs. In addition, miR-450b significantly promoted the osteogenic differentiation in hBMSCs via targeting FBXW7. Furthermore, XIST knockdown could inhibit the symptom of osteoporosis in vivo. IRF-1 promoted the osteogenic differentiation via mediation of lncRNA XIST/miR-450b/FBXW7 axis, and this finding might shed novel insights on exploring new ideas against osteoporosis.

Plant-derived natural products and combination therapy in liver cancer

Liver cancer is one of the malignant cancers globally and seriously endangers human health because of its high morbidity and mortality. Plant-derived natural products have been evaluated as potential anticancer drugs due to low side effects and high anti-tumor efficacy. However, plant-derived natural products also have defects of poor solubility and cumbersome extraction process. In recent years, a growing numbers of plant derived natural products have been used in combination therapy of liver cancer with conventional chemotherapeutic agents, which has improved clinical efficacy through multiple mechanisms, including inhibition of tumor growth, induction of apoptosis, suppression of angiogenesis, enhancement of immunity, reversal of multiple drug resistance and reduction of side effects. The therapeutic effects and mechanisms of plant-derived natural products and combination therapy on liver cancer are reviewed to provide references for developing anti-liver-cancer strategies with high efficacy and low side effects.

Potential of Compounds Originating from the Nature to Act in Hepatocellular Carcinoma Therapy by Targeting the Tumor Immunosuppressive Microenvironment: A Review

Hepatocellular carcinoma (HCC), the most prevalent subtype of liver cancer, is the second main reason for cancer-related deaths worldwide. In recent decades, sufficient evidence supported that immunotherapy was a safe and effective treatment option for HCC. However, tolerance and frequent recurrence and metastasis occurred in patients after immunotherapy due to the complicated crosstalk in the tumor immunosuppressive microenvironment (TIME) in HCC. Therefore, elucidating the TIME in HCC and finding novel modulators to target TIME for attenuating immune suppression is critical to optimize immunotherapy. Recently, studies have shown the potentially immunoregulatory activities of natural compounds, characterized by multiple targets and pathways and low toxicity. In this review, we concluded the unique role of TIME in HCC. Moreover, we summarized evidence that supports the hypothesis of natural compounds to target TIME to improve immunotherapy. Furthermore, we discussed the comprehensive mechanisms of these natural compounds in the immunotherapy of HCC. Accordingly, we present a well-grounded review of the naturally occurring compounds in cancer immunotherapy, expecting to shed new light on discovering novel anti-HCC immunomodulatory drugs from natural sources.

Midazolam exhibits antitumour and enhances the efficiency of Anti-PD-1 immunotherapy in hepatocellular carcinoma

BACKGROUND

Midazolam (MDZ) is an anaesthetic that is widely used for anxiolysis and sedation. More recently, MDZ has also been described to be related to the outcome of various types of carcinomas. However, how MDZ influences the progression of hepatocellular carcinoma (HCC) and its effects on the biological function and tumour immune microenvironment of this type of tumour remain unknown.

METHODS

The effects of MDZ on the proliferation, invasion, and migration of HCC cell lines were examined in vitro using the Cell Counting Kit 8 (CCK8), 5-ethynyl-2'-deoxyuridine (EdU), Transwell, and wound healing assays. Additionally, western blotting was employed to confirm that PD-L1 was expressed. Chromatin immunoprecipitation-seq (ChIP-seq) analysis was used to pinpoint the transcriptional regulation regions of NF-κB and programmed death-ligand 1 (PD-L1). A C57BL/6 mouse model was used to produce subcutaneous HCC tumors in order to evaluate the in vivo performance of MDZ. Mass spectrometry was also used to assess changes in the tumour immunological microenvironment following MDZ injection.

RESULTS

The HCC-LM3 and Hep-3B cell lines' proliferation, invasion, and migration were controlled by MDZ, according to the results of the CCK8, EdU, Transwell, and wound healing assays. PD-L1 expression was shown by ChIP-seq analysis to be boosted by NF-κB, and by Western blotting analysis, it was shown that MDZ downregulated the expression of NF-κB. Additionally, in vivo tests revealed that intraperitoneal MDZ injections reduced HCC tumor development and enhanced the effectiveness of anti-PD-1 therapy. The CD45⁺ immune cell proportions were higher in the MDZ group than in the PBS group, according to the mass spectrometry results. Injection of MDZ resulted in a decrease in the proportions of CD4⁺ T cells, CD8⁺ T cells, natural killer (NK) cells, monocytes, Tregs, and M2 macrophages and a rise in the proportion of dendritic cells. Additionally, the concentrations of the cytokines IFN-g and TNF-a were noticeably raised whereas the concentrations of the CD8⁺ T-cell fatigue markers ICOS, TIGIT, and TIM3 were noticeably lowered.

CONCLUSION

According to this study, MDZ inhibited the progression of HCC by inhibiting the NF-κB pathway and reducing the exhaustion of CD8⁺ T cells. In clinical practice, MDZ combined with anti-PD-1 therapy might contribute to synergistically improving the antitumor efficacy of HCC treatment.