Targeting CD8+ T cells with natural products for tumor therapy: Revealing insights into the mechanisms.

BACKGROUND: Despite significant advances in cancer immunotherapy over the past decades, such as T cell-engaging chimeric antigen receptor (CAR)-T cell therapy and immune checkpoint blockade (ICB), therapeutic failure resulting from various factors remains prevalent. Therefore, developing combinational immunotherapeutic strategies is of great significance for improving the clinical outcome of cancer immunotherapy. Natural products are substances that naturally exist in various living organisms with multiple pharmacological or biological activities, and some of them have been found to have anti-tumor potential. Notably, emerging evidences have suggested that several natural compounds may boost the anti-tumor effects through activating immune response of hosts, in which CD8+ T cells play a pivotal role. METHODS: The data of this review come from PubMed, Web of Science, Google Scholar, and ClinicalTrials (https://clinicaltrials.gov/) with the keywords "CD8+ T cell", "anti-tumor", "immunity", "signal 1", "signal 2", "signal 3", "natural products", "T cell receptor (TCR)", "co-stimulation", "co-inhibition", "immune checkpoint", "inflammatory cytokine", "hesperidin", "ginsenoside", "quercetin", "curcumin", "apigenin", "dendrobium officinale polysaccharides (DOPS)", "luteolin", "shikonin", "licochalcone A", "erianin", "resveratrol", "procyanidin", "berberine", "usnic acid", "naringenin", "6-gingerol", "ganoderma lucidum polysaccharide (GL-PS)", "neem leaf glycoprotein (NLGP)", "paclitaxel", "source", "pharmacological activities", and "toxicity". These literatures were published between 1993 and 2023. RESULTS: Natural products have considerable advantages as anti-tumor drugs based on the various species, wide distribution, low price, and few side effects. This review summarized the effects and mechanisms of some natural products that exhibit anti-tumor effects via targeting CD8+ T cells, mainly focused on the three signals that activate CD8+ T cells: TCR, co-stimulation, and inflammatory cytokines. CONCLUSION: Clarifying the role and underlying mechanism of natural products in cancer immunotherapy may provide more options for combinational treatment strategies and benefit cancer therapy, to shed light on identifying potential natural compounds for improving the clinical outcome in cancer immunotherapy.

Protein-level mutant p53 reporters identify druggable rare precancerous clones in noncancerous tissues.

Detecting and targeting precancerous cells in noncancerous tissues is a major challenge for cancer prevention. Massive stabilization of mutant p53 (mutp53) proteins is a cancer-specific event that could potentially mark precancerous cells, yet in vivo protein-level mutp53 reporters are lacking. Here we developed two transgenic protein-level mutp53 reporters, p53R172H-Akaluc and p53-mCherry, that faithfully mimic the dynamics and function of mutp53 proteins in vivo. Using these reporters, we identified and traced rare precancerous clones in deep noncancerous tissues in various cancer models. In classic mutp53-driven thymic lymphoma models, we found that precancerous clones exhibit broad chromosome number variations, upregulate precancerous stage-specific genes such as Ybx3 and enhance amino acid transport and metabolism. Inhibiting amino acid transporters downstream of Ybx3 at the early but not late stage effectively suppresses tumorigenesis and prolongs survival. Together, these protein-level mutp53 reporters reveal undercharacterized features and vulnerabilities of precancerous cells during early tumorigenesis, paving the way for precision cancer prevention.

Prediction of post-Darcy flow based on the spatial non-local distribution of hydraulic gradient: Preliminary assessment of wastewater management.

Understanding high-velocity pollutant transport dependent on the large hydraulic gradient and/or heterogeneity of the aquifer and criteria for the onset of post-Darcy flow have attracted considerable attention in water resources and environmental engineering applications. In this study, a parameterized model is established based on the equivalent hydraulic gradient (EHG) which affected by spatial nonlocality of nonlinear head distribution due to the inhomogeneity at a wide range of scales. Two parameters relevant to the spatially non-local effect were selected to predict the development of post-Darcy flow. Over 510 sets of laboratory one-dimensional (1-D) steady hydraulic experimental data were used to validate the performance of this parameterized EHG model. The results show that (1) the spatial nonlocal effect of the whole upstream is related to the mean grain size of the medium, and the anomalous variation due to the small grain size implies the existence of the particle size threshold. (2) The parameterized EHG model can effectively capture the nonlinear trend that fails to be described by the traditional local form of nonlinear models, even if the specific discharge stabilizes at the later stages. (3) The Sub-Darcy flow distinguished by the parameterized EHG model can be equated to the post-Darcy flow, and then the criteria for the post-Darcy flow will be strictly distinguished under the premise of determining the hydraulic conductivity. The results of this study facilitate the identification and prediction of high-velocity non-Darcian flow in wastewater management and provide insight into mass transport by advection at the fine-scale.

Deciphering the Clinical Significance and Kinase Functions of GSK3α in Colon Cancer by Proteomics and Phosphoproteomics.

GSK3α and GSK3ß are two GSK3 isoforms with 84% overall identity and 98% identity in their catalytic domains. GSK3ß plays important roles in the pathogenesis of cancer, while GSK3α has long been considered a functionally redundant protein of GSK3ß. Few studies have specifically investigated the functions of GSK3α. In this study, unexpectedly, we found that the expression of GSK3α, but not GSK3ß, was significantly correlated with the overall survival of colon cancer patients in 4 independent cohorts. To decipher the roles of GSK3α in colon cancer, we profiled the phosphorylation substrates of GSK3α and uncovered 156 phosphosites from 130 proteins specifically regulated by GSK3α. A number of these GSK3α-mediated phosphosites have never been reported before or have been incorrectly identified as substrates of GSK3ß. Among them, the levels of HSF1S303p, CANXS583p, MCM2S41p, POGZS425p, SRRM2T983p, and PRPF4BS431p were significantly correlated with the overall survival of colon cancer patients. Further pull-down assays identified 23 proteins, such as THRAP3, BCLAF1, and STAU1, showing strong binding affinity to GSK3α. The interaction between THRAP3 and GSK3α was verified by biochemical experiments. Notably, among the 18 phosphosites of THRAP3, phosphorylation at S248, S253, and S682 is specifically mediated by GSK3α. Mutation of S248 to D (S248D), which mimics the effect of phosphorylation, obviously increased cancer cell migration and the binding affinity to proteins related to DNA damage repair. Collectively, this work not only discloses the specific function of GSK3α as a kinase but also suggests GSK3α as a promising therapeutic target for colon cancer.

Phenotypic Heterogeneity Analysis of APC-Mutant Colon Cancer by Proteomics and Phosphoproteomics Identifies RAI14 as a Key Prognostic Determinant in East Asians and Westerners.

Adenomatous polyposis coli (APC) is an important tumor suppressor and is mostly linked to the regulation of the Wnt/ß-catenin signaling pathway. APC mutation has been identified as an early event in more than 80% of sporadic colorectal cancers (CRCs). Moreover, prognostic differences are observed in CRC patients with APC mutations. Although previous genomics studies have investigated the roles of concomitant gene mutations in determining the phenotypic heterogeneity of APC-mutant tumors, valuable prognostic determinants for APC-mutant CRC patients are still lacking. Based on the proteome and phosphoproteome data, we classified APC-mutant colon cancer patients and revealed genomic, proteomic, and phosphoproteomic heterogeneity in APC-mutant tumors. More importantly, we identified RAI14 as a key prognostic determinant for APC-mutant but not APC-wildtype colon cancer patients. The heterogeneity and the significance of prognostic biomarkers in APC-mutant tumors were further validated in the Clinical Proteomic Tumor Analysis Consortium (CPTAC) colon cancer cohort. In addition, we found that colon cancer patients with high expression of RAI14 were less responsive to chemotherapy. Knockdown of RAI14 in cell lines led to reduced cell migration and changes in epithelial-mesenchymal transition (EMT)-related markers. Mechanistically, knockdown of RAI14 remodeled the phosphoproteome associated with cell adhesion, which might affect EMT marker expression and promote F-actin degradation. Collectively, this work describes the phenotypic heterogeneity of APC-mutant tumors and identifies RAI14 as an important prognostic determinant for APC-mutant colon cancer patients. The prognostic utility of RAI14 in APC-mutant colon cancer will provide early warning and increase the chance of successful treatment.

UBE2O promotes lipid metabolic reprogramming and liver cancer progression by mediating HADHA ubiquitination.

Cancer cells rely on heightened protein quality control mechanisms, including the ubiquitin-proteosome system that is predominantly driven by ubiquitination comprising E1, E2, and E3 trienzyme cascades. Although E3s have been extensively studied, the implication of E2s in tumorigenesis is poorly defined. Here we reveal a critical E2 in the pathogenesis of hepatocellular carcinoma (HCC). Among all of E2s, UBE2O shows the strongest association with HCC survival prognosis, and its expression is increased in HCC tumors. Accordingly, UBE2O deficiency inhibits HCC growth and metastasis both in vitro and in vivo, while its overexpression has opposite effects. Depending on both E2 and E3 enzymatic activities, UBE2O can interact with and mediate the ubiquitination and degradation of HADHA, a mitochondrial ß-oxidation enzyme, thereby modulating lipid metabolic reprogramming. HADHA is reduced in HCC tumors and inversely correlated with UBE2O levels. Importantly, HADHA acts as a tumor suppressor and primarily mediates UBE2O's function on HCC. Moreover, liver-specific deletion of Ube2o in mice are resistant to DEN-induced hepatocarcinogenesis, along with HADHA upregulation and reduced hepatic lipid accumulation. These data reveal UBE2O as a novel oncogenic driver for metabolic reprogramming and HCC development, highlighting the potential of targeting UBE2O/HADHA axis for HCC therapy.

Human Amnion-Derived MSCs Alleviate Acute Lung Injury and Hinder Pulmonary Fibrosis Caused by Paraquat in Rats.

Methods: First, the purity of hAD-MSCs was determined by morphological observation and FCM, and the effects on the survival of paraquat-poisoned Sprague-Dawley rats were observed. All rats were randomly divided into three groups, defined as the sham control group (n = 8), model group (n = 15), and hAD-MSC-transplanted group (n = 17). Pneumonocyte damage and inflammatory cell infiltration were investigated in the three groups of rats, untreated control, paraquat only, and paraquat+hAD-MSC transplanted, using H&E staining. Fibrosis was investigated in three groups of rats using Masson's trichrome staining and Sirius red staining. The profibrotic factor TGF-ß1, the composition of fibrotic collagen HYP, and the hAD-MSC-secreted immunosuppressive factor HLA-G5 in serum were investigated in the three groups of rats using ELISA. Furthermore, the distribution of hAD-MSCs was investigated in the three groups of rats using immunohistochemistry and hematoxylin staining. Results: The hAD-MSCs exhibited typical hallmarks of MSCs, improved the state of being and survival of paraquat-poisoned rats, reduced both lung injury and inflammation, and inhibited the progression of pulmonary fibrosis by decreasing the deposition of collagen and the secretion of both TGF-ß1 and HYP. The hAD-MSCs could survive in damaged lungs and secreted appropriate amounts of HLA-G5 into the serum. Conclusion: The obtained results indicate that hAD-MSCs used to treat paraquat-induced lung injury may work through anti-inflammatory and immunosuppressive pathways and the downregulation of profibrotic elements. This study suggests that the transplantation of hAD-MSCs is a promising therapeutic approach for the treatment of paraquat-intoxicated patients.

Pancreatic ß cell microRNA-26a alleviates type 2 diabetes by improving peripheral insulin sensitivity and preserving ß cell function.

Type 2 diabetes (T2D) is characterized by insulin resistance along with pancreatic ß cell failure. ß cell factors are traditionally thought to control glucose homeostasis by modulating insulin levels, not insulin sensitivity. Exosomes are emerging as new regulators of intercellular communication. However, the role of ß-cell-derived exosomes in metabolic homeostasis is poorly understood. Here, we report that microRNA-26a (miR-26a) in ß cells not only modulates insulin secretion and ß cell replication in an autocrine manner but also regulates peripheral insulin sensitivity in a paracrine manner through circulating exosomes. MiR-26a is reduced in serum exosomes of overweight humans and is inversely correlated with clinical features of T2D. Moreover, miR-26a is down-regulated in serum exosomes and islets of obese mice. Using miR-26a knockin and knockout mouse models, we showed that miR-26a in ß cells alleviates obesity-induced insulin resistance and hyperinsulinemia. Mechanistically, miR-26a in ß cells enhances peripheral insulin sensitivity via exosomes. Meanwhile, miR-26a prevents hyperinsulinemia through targeting several critical regulators of insulin secretion and ß cell proliferation. These findings provide a new paradigm for the far-reaching systemic functions of ß cells and offer opportunities for the treatment of T2D.

An Unbiased Immunoaffinity-Based Strategy for Profiling Covalent Drug Targets In Vivo.

Activity-based chemical proteomics approaches used for identifying cellular targets of drugs are mainly dependent on the availability of probes derived from drugs. However, all chemical probes are structurally different from the drugs themselves and cannot fully mimic the real actions of drugs in cells. Here we present a concise and unbiased immunoaffinity-based strategy for identifying covalent drug targets in vivo. By using the specific antibody, we not only confirm the well-known ibrutinib-binding target BTK, but also identify some previously undescribed strongly binding proteins, such as CKAP4 in human cell lines and TAP1 in mouse organs. The observed target profiles between species may partially explain why certain drug candidates are very effective in mice but not in humans. This approach avoids the chemical modification of drugs, eliminates the nonspecific bindings of chemical probes, and allows to unbiasedly decode the underlying mechanisms of action of covalent drugs.

Metabolism-induced tumor activator 1 (MITA1), an Energy Stress-Inducible Long Noncoding RNA, Promotes Hepatocellular Carcinoma Metastasis.

Metastasis is the main cause of cancer-related death, yet the underlying mechanisms are still poorly understood. Long noncoding RNAs (lncRNAs) are emerging as crucial regulators of malignancies; however, their functions in tumor metastasis remain largely unexplored. In this study, we identify a lncRNA, termed metabolism-induced tumor activator 1 (MITA1), which is up-regulated in hepatocellular carcinoma (HCC) and contributes to metastasis. MITA1, a chromatin-enriched lncRNA discovered by our nuclear RNA sequencing, is significantly induced by energy stress. This induction of MITA1 is governed by the liver kinase B1-adenosine monophosphate-activated protein kinase (LKB1-AMPK) pathway and DNA methylation. Knockdown of MITA1 dramatically inhibits the migration and invasion of liver cancer cells in vitro and HCC metastasis in vivo. Mechanistically, MITA1 promotes the epithelial-mesenchymal transition, an early and central step of metastasis, which may partly attribute to an increase in Slug (snail family zinc finger 2) transcription. MITA1 deficiency reduces the expression of the mesenchymal cell markers, especially Slug, whereas Slug overexpression greatly impairs the effects of MITA1 deficiency on HCC migration and invasion. Correspondingly, there is a positive correlation between the levels of MITA1 and Slug precursors in HCC tissues. Conclusion: Our data reveal MITA1 as a crucial driver of HCC metastasis, and highlight the identified AMPK-MITA1-Slug axis as a potential therapeutic strategy for HCC.

Tumor cells induce LAMP2a expression in tumor-associated macrophage for cancer progression.

BACKGROUND: Tumor cells benefit from tumor-associated macrophages (TAMs) promoting tumor growth and modulating functions of other cells in tumor microenvironment (TME). However, how tumor cells regulate the property of TAMs during tumor invasion remains to be defined. METHODS: Mouse tumor models and cancer patients' samples were analyzed to determine LAMP2a expression in TAMs. In vitro mouse primary macrophages were used to assess LAMP2a-modulated macrophage activation, and to verify LAMP2a's target proteins. The effect of LAMP2a-knockdown on tumor progression and TME maintaining was determined by using mouse tumor models. FINDINGS: Lysosome associated membrane protein type 2A (LAMP2a) is upregulated in TAMs by tumor cells and important for tumor progression. LAMP2a expression in TAMs, but not in tumor cells, is associated with poor prognosis in breast cancer. LAMP2a inactivation induced by either shRNA or CRISPR/Cas9 prevents TAMs activation and tumor growth. LAMP2a degrades PRDX1 (peroxiredoxin 1) and CRTC1 (CREB-regulated transcription coactivator 1) to promote macrophage pro-tumorigenic activation. INTERPRETATION: Our study suggests that tumor cells utilize LAMP2a-PRDX1/CRTC1 axis to modulate TAMs activation and promote tumor growth, reveals the role of LAMP2a in macrophage study and TAM-targeting tumor immunotherapy. FUND: National Natural Science Foundation of China (No. 81602492); National Key Research and Development Program of China (No. 2016YFA0201402).

Erratum: Author Correction to: TRIM29 negatively controls antiviral immune response through targeting STING for degradation.

[This corrects the article DOI: 10.1038/s41421-018-0010-9.].

TRIM29 negatively controls antiviral immune response through targeting STING for degradation.

Innate immune system is armed by several lines of pattern recognition receptors to sense various viral infection and to initiate antiviral immune response. This process is under a tight control and the negative feedback induced by infection and/or inflammation is critical to maintain immune homoeostasis and to prevent autoimmune disorders, however, the molecular mechanism is not fully understood. Here we report TRIM29, a ubiquitin E3 ligase, functions as an inducible negative regulator of innate immune response triggered by DNA virus and cytosolic DNA. DNA virus and cytosolic DNA stimulation induce TRIM29 expression robustly in macrophages and dendritic cells, although the basal level of TRIM29 is undetectable in those cells. TRIM29 deficiency elevates IFN-I and proinflammatory cytokine production upon viral DNA and cytosolic dsDNA stimulation. Consistently, in vivo experiments show that TRIM29-deficient mice are more resistant to HSV-1 infection than WT controls, indicated by better survival rate and reduced viral load in organs. Mechanism studies suggest that STING-TBK1-IRF3 signaling pathway in TRIM29 KO cells is significantly enhanced and the degradation of STING is impaired. Furthermore, we identify that TRIM29 targets STING for K48 ubiquitination and degradation. This study reveals TRIM29 as a crucial negative regulator in immune response to DNA virus and cytosolic DNA, preventing potential damage caused by overcommitted immune responses.

Landscape of the regulatory elements for lysine 2-hydroxyisobutyrylation pathway.

Short-chain fatty acids and their corresponding acyl-CoAs sit at the crossroads of metabolic pathways and play important roles in diverse cellular processes. They are also precursors for protein post-translational lysine acylation modifications. A noteworthy example is the newly identified lysine 2-hydroxyisobutyrylation (Khib) that is derived from 2-hydroxyisobutyrate and 2-hydroxyisobutyryl-CoA. Histone Khib has been shown to be associated with active gene expression in spermatogenic cells. However, the key elements that regulate this post-translational lysine acylation pathway remain unknown. This has hindered characterization of the mechanisms by which this modification exerts its biological functions. Here we show that Esa1p in budding yeast and its homologue Tip60 in human could add Khib to substrate proteins both in vitro and in vivo. In addition, we have identified HDAC2 and HDAC3 as the major enzymes to remove Khib. Moreover, we report the first global profiling of Khib proteome in mammalian cells, identifying 6 548 Khib sites on 1 725 substrate proteins. Our study has thus discovered both the "writers" and "erasers" for histone Khib marks, and major Khib protein substrates. These results not only illustrate the landscape of this new lysine acylation pathway, but also open new avenues for studying diverse functions of cellular metabolites associated with this pathway.

[Preliminary Study on the Wnt5a Expression in Obese Mice with Hepatocellular Carcinoma].

OBJECTIVES: To investigate the Wnt5a expression in obese mice with hepatocellular carcinoma. METHODS: Two groups of 6-week C57BL/6J mice were fed with chow-diet and high-fat-diet for 8 weeks respectively, to establish obesity model in the latter group. Mice in Hepal-6 group (including normal-body mass mice and obese mice) were injected with Hepa1-6 hepatocarcinoma cell lines through caudal vein, while the controls were given NS. Serum and tissue samples were taken at the age of 18 weeks for serological and morphological study. The expression of Wnt5a and ß-catenin in liver were examined by immunohistochemistry. RESULTS: At the age of 18-week, tatty degeneration was observed in the livers of obese control mice. Tumor cell masses were found in the livers of both obese and (including normal-body mass mice and obese mice) control mice by inoculation with Hepal-6, while focal necrosis was only observed in the obese+Hepal-6 group. The levels of serum transaminases, cholesterol and alpha-fetoprotein (AFP) were significantly different between groups ( P<0.05). The immunohistochemistry showed that the highest expression of Wnt5a was observed in liver tissues of normal control group, followed in sequence by obese control group, normal+Hepal-6 group, and obese+Hepal-6 group ( P<0.05). The expression of ß-catenin was just opposite ( P<0.05). CONCLUSIONS: The expression of Wnt5a was decreased, and the ß-catenin was abnormal accumulation. It may be closely related to the formation and progression of hepatocellular carcinoma.