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.

Traditional Chinese Medicine in Regulating Tumor Microenvironment.

Tumor microenvironment (TME) is a complex and integrated system containing a variety of tumor-infiltrating immune cells and stromal cells. They are closely connected with cancer cells and influence the development and progression of cancer. Traditional Chinese medicine (TCM) is an important complementary therapy for cancer treatment in China. It mainly eliminates cancer cells by regulating TME. The aim of this review is to systematically summarize the crosstalk between tumor cells and TME, and to summarize the research progress of TCM in regulating TME. The review is of great significance in revealing the therapeutic mechanism of action of TCM, and provides an opportunity for the combined application of TCM and immunotherapy in cancer treatment.

Seseli bocconei Guss. and S. tortuosum subsp. maritimum Guss. essential oils inhibit colon cancer cell viability.

In this study, the chemical compositions of two essential oils (EOs) obtained from different parts (flowers, leaves, stems, and roots) of Seseli bocconei Guss. and of Seseli tortuosum subsp. maritimum Guss., wild endemic species of Sicily, were investigated. The main classes of metabolites for the essential oils of S. bocconei were, respectively, monoterpenes hydrocarbons for flowers, sesquiterpenes hydrocarbons for leaves, and a breakdown between the two previously mentioned classes for stems. In the case of S. tortuosum subsp. maritimum, on the other hand, the main metabolite class for all the vegetative parts analyzed (flowers, stems, and roots) was monoterpene hydrocarbons, with a slight percentage in other non-terpenoid compounds. Furthermore, the EOs' antitumor effects against HCT116, human colon cancer cells were evaluated. Cell viability assays evidenced that stems' EOs of both plants exhibit strong cytotoxic effects at low concentrations, while the EOs from other vegetative parts do not show a relevant effect. In fact, EO of stems of S. tortuosum subsp. maritimum reduced the cell viability of 82% at the concentration of 125 µg/mL, while at the concentration of 250 µg/mL of stems EO of S. bocconei the 97% of cells resulted dead. The analysis of the effects exerted by the main phytocostituents (S-(-)-limonene, R-(+)-limonene, sabinene, (1S)-(-)-α-pinene, (1R)-(+)-α-pinene, and (-)-ß-pinene, and germacrene D) of these EOs on colon cancer cells revealed germacrene D as a new promising molecule with anticancer properties that deserve to be explored in future directions.

Enrichment of Isaria felina Culture with Selenium Enhances its in vivo Antitumor Effects on H22 Hepatoma via Decreasing the Expression of VEGF.

BACKGROUND: The polysaccharide extract of C. sinensis, Isaria felina (IF), has antitumor effects. Selenium (Se) can improve disease prevention and reduce the toxicity of toxic elements, but the effect of Se-enriched IF on hepatoma remains unknown. OBJECTIVE: To determine the organic transformation of Se and compare the antitumor effects between Se-enriched IF (IF-Se) and IF on xenograft H22 hepatoma-bearing mice. METHODS: Se was added to the solid-state culture medium, and the organic Se content was detected by HPLC-ICP-MS. Forty-two Kunming mice were randomly divided into seven groups to test the antitumor effects of low- (300 mg/kg) and high- (600 mg/kg) doses of IF-Se and IF through xenograft. Huai'er granules were administered as the positive control. In addition, interleukin (IL)-2 and vascular endothelial growth factor (VEGF) expressions were measured by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry method. RESULTS: The conversion rate in the IF-Se70, IF-Se140, and IF-Se280 groups were 91.5%, 93.4%, and 89.3%, respectively. Therefore, IF-Se140 was used to carry out the subsequent experiments. The tumor inhibition rates of IF-Se were significantly higher compared with IF (P < 0.05). Moreover, the spleen coefficient, IL-2, and VEGF expression levels significantly decreased (all Ps < 0.05), and the thymus coefficient significantly increased (P < 0.05) in the high-dose IF-Se group compared with the model control group. CONCLUSION: The inhibitory effects of IF on H22 hepatoma-bearing mice were enhanced after Se enrichment. Therefore, Se-enriched IF might be a new strategy for treating hepatoma.

Inhibition of Colorectal Cancer Cell Proliferation by Treatment with Itadori Leaf Extract.

Treatment with itadori extract inhibited the growth of mouse colon cancer cells (Colon-26) in mice. In addition, it induced DNA fragmentation and caspase 3/7 activation in Colon-26 cells, suggesting potent induction of apoptosis. Itadori extracts are rich in neochlorogenic acid and rutin and also contain quercetin and piceatannol. These polyphenols are thought to be involved in the observed DNA fragmentation and caspase 3/7 activation in colon cancer cells and may thus have anticancer effects. There is hence scope for development of the leaf of itadori, which currently has only a few known uses, as a novel anti-tumor therapeutic.

Micro-/Nano-Structures on Biodegradable Magnesium@PLGA and Their Cytotoxicity, Photothermal, and Anti-Tumor Effects.

The size and structural control of particulate carriers for imaging agents and therapeutics are constant themes in designing smart delivery systems. This is motivated by the causal relationship between geometric parameters and functionalities of delivery vehicles. Here, both in vitro and in vivo, the controlling factors for cytotoxicity, photothermal, and anti-tumor effects of biodegradable magnesium@poly(lactic-co-glycolic acid (Mg@PLGA) particulate carriers with different sizes and shell thicknesses are investigated. Mg@PLGA microspheres fabricated by microfluidic emulsification are shown to have higher Mg encapsulation efficiency, 87%, than nanospheres by ultrasonic homogenization, 50%. The photothermal and anti-tumor effects of Mg@PLGA spheres are found to be dictated by their Mg content, irrelevant to size and structural features, as demonstrated in both in vitro cell assays and in vivo mice models. These results also provide important implications for designing and fabricating stimuli-responsive drug delivery vehicles.

The Olive Leaves Extract Has Anti-Tumor Effects against Neuroblastoma through Inhibition of Cell Proliferation and Induction of Apoptosis.

Neuroblastoma (NB) is the most common extra-cranial solid tumor of pediatric age. The prognosis for high-risk NB patients remains poor, and new treatment strategies are desirable. The olive leaf extract (OLE) is constituted by phenolic compounds, whose health beneficial effects were reported. Here, the anti-tumor effects of OLE were investigated in vitro on a panel of NB cell lines in terms of (i) reduction of cell viability; (ii) inhibition of cell proliferation through cell cycle arrest; (iii) induction of apoptosis; and (iv) inhibition of cell migration. Furthermore, cytotoxicity experiments, by combining OLE with the chemotherapeutic topotecan, were also performed. OLE reduced the cell viability of NB cells in a time- and dose-dependent manner in 2D and 3D models. NB cells exposed to OLE underwent inhibition of cell proliferation, which was characterized by an arrest of the cell cycle progression in G0/G1 phase and by the accumulation of cells in the sub-G0 phase, which is peculiar of apoptotic death. This was confirmed by a dose-dependent increase of Annexin V+ cells (peculiar of apoptosis) and upregulation of caspases 3 and 7 protein levels. Moreover, OLE inhibited the migration of NB cells. Finally, the anti-tumor efficacy of the chemotherapeutic topotecan, in terms of cell viability reduction, was greatly enhanced by its combination with OLE. In conclusion, OLE has anti-tumor activity against NB by inhibiting cell proliferation and migration and by inducing apoptosis.

Pros and Cons of the Cannabinoid System in Cancer: Focus on Hematological Malignancies.

The endocannabinoid system (ECS) is a composite cell-signaling system that allows endogenous cannabinoid ligands to control cell functions through the interaction with cannabinoid receptors. Modifications of the ECS might contribute to the pathogenesis of different diseases, including cancers. However, the use of these compounds as antitumor agents remains debatable. Pre-clinical experimental studies have shown that cannabinoids (CBs) might be effective for the treatment of hematological malignancies, such as leukemia and lymphoma. Specifically, CBs may activate programmed cell death mechanisms, thus blocking cancer cell growth, and may modulate both autophagy and angiogenesis. Therefore, CBs may have significant anti-tumor effects in hematologic diseases and may synergistically act with chemotherapeutic agents, possibly also reducing chemoresistance. Moreover, targeting ECS might be considered as a novel approach for the management of graft versus host disease, thus reducing some symptoms such as anorexia, cachexia, fatigue, anxiety, depression, and neuropathic pain. The aim of the present review is to collect the state of the art of CBs effects on hematological tumors, thus focusing on the essential topics that might be useful before moving into the clinical practice.

[Research progress on anti-tumor effects and mechanisms of triptolide and its combined application].

Tumors are major chronic diseases and seriously threaten human health all over the world. How to effectively control and cure tumors is one of the most pivotal problems in the medical field. At present,surgery,radiotherapy and chemotherapy are still the main treatment methods. However,the side effects of radiotherapy and chemotherapy cannot be underestimated. Therefore,it is of great practical significance to find new anti-cancer drugs with low toxicity,high efficiency and targeting to cancer cells. With the increasing incidence of tumor,the anti-tumor effect of traditional Chinese medicine has increasingly become a research hotspot. Triptolide,which is a natural diterpenoid active ingredient derived from of Tripterygium wilfordii,as one of the highly active components,has anti-inflammatory,immunosuppressive,anti-tumor and other multiple effects. A large number of studies have confirmed that it has good anti-tumor activity against various tumors in vivo and in vitro. It can play an anti-tumor role by inhibiting the proliferation of cancer cells,inducing apoptosis of cancer cells,inducing autophagy of cancer cells,blocking the cell cycle,inhibiting the migration,invasion and metastasis of cancer cells,reversing multidrug resistance,mediating tumor immunity and inhibiting angiogenesis. On the basis of literatures,this paper reviews the anti-tumor effect and mechanism of triptolide,and analyzes the current situation of triptolide combined with other chemotherapy drugs,in order to promote deep research and better clinical application about triptolide.

Research progress on anti-tumor effects and mechanisms of triptolide and its combined application / 中国中药杂志

Tumors are major chronic diseases and seriously threaten human health all over the world. How to effectively control and cure tumors is one of the most pivotal problems in the medical field. At present,surgery,radiotherapy and chemotherapy are still the main treatment methods. However,the side effects of radiotherapy and chemotherapy cannot be underestimated. Therefore,it is of great practical significance to find new anti-cancer drugs with low toxicity,high efficiency and targeting to cancer cells. With the increasing incidence of tumor,the anti-tumor effect of traditional Chinese medicine has increasingly become a research hotspot. Triptolide,which is a natural diterpenoid active ingredient derived from of Tripterygium wilfordii,as one of the highly active components,has anti-inflammatory,immunosuppressive,anti-tumor and other multiple effects. A large number of studies have confirmed that it has good anti-tumor activity against various tumors in vivo and in vitro. It can play an anti-tumor role by inhibiting the proliferation of cancer cells,inducing apoptosis of cancer cells,inducing autophagy of cancer cells,blocking the cell cycle,inhibiting the migration,invasion and metastasis of cancer cells,reversing multidrug resistance,mediating tumor immunity and inhibiting angiogenesis. On the basis of literatures,this paper reviews the anti-tumor effect and mechanism of triptolide,and analyzes the current situation of triptolide combined with other chemotherapy drugs,in order to promote deep research and better clinical application about triptolide.

Beneficial Phytochemicals with Anti-Tumor Potential Revealed through Metabolic Profiling of New Red Pigmented Lettuces (Lactuca sativa L.).

The present study aimed to compare polyphenols among red lettuce cultivars and identify suitable cultivars for the development and utilization of healthy vegetables. Polyphenols, mineral elements, and antioxidant activity were analyzed in the leaves of six red pigmented lettuce (Lactuca sativa L.) cultivars; thereafter, we assessed the anti-tumor effects of cultivar B-2, which displayed the highest antioxidant activity. Quadrupole-Orbitrap mass spectrometry analysis revealed four classes of polyphenols in these cultivars. The composition and contents of these metabolites varied significantly among cultivars and primarily depended on leaf color. The B-2 cultivar had the highest antioxidant potential than others because it contained the highest levels of polyphenols, especially anthocyanin, flavone, and phenolic acid; furthermore, this cultivar displayed anti-tumor effects against the human lung adenocarcinoma cell line A549, human hepatoma cell line Bel7402, human cancer colorectal adenoma cell line HCT-8, and HT-29 human colon cancer cell line. Hence, the new red-leaf lettuce cultivar B-2 has a distinct metabolite profile, with high potential for development and utilization of natural phytochemical and mineral resources in lettuces and can be used as a nutrient-dense food product.

[Research on preparation process of andrographolide-glycyrrhizic acid polymeric micelles].

This study aimed to prepare andrographolide (AP)-loaded glycyrrhizic acid (GA) micelles (AP-GA)-PMs to enhance the solubility and anti-tumor effect of andrographolide. Firstly, andrographolide (AP) was used as the model drug and glycyrrhizic acid (GA) as carriers to prepare (AP-GA)-PMs. Then the preparation methods and the ratios of drug and carrier were screened and optimized based on particle size, encapsulation efficiency (EE) and loading capacity of micelles. Finally, the pharmaceutical characters and the inhibition rate on HepG2 cells were evaluated on the (AP-GA)-PMs prepared by optimal process. The results showed that the prepared micelles under the optimal process had a nanosize of (127.11±1.38) nm, zeta potential of (-24.01±0.55) mV, the entrapment efficiency rate of (92.01±4.02)% , the drug loading rate of (51.44±1.24)% and high storage stability at 4 °C in 30 d, with slow but highly stable in vitro release. Moreover, (AP-GA)-PMs with the IC50 value of 19.25 mg·L⁻¹ had a more synergistic and better anti-tumor effect in comparison with AP (IC50=122.40 mg·L⁻¹) on HepG2 cells (P<0.01). In conclusion, the (AP-GA)-PMs prepared with glycyrrhizic acid as a carrier had a small particle size, large drug loading capacity, and high stability, and could significantly improve the anti-tumor effects of AP.

Anticancer activity of glucomoringin isothiocyanate in human malignant astrocytoma cells.

Isothiocyanates (ITCs) released from their glucosinolate precursors have been shown to inhibit tumorigenesis and they have received significant attention as potential chemotherapeutic agents against cancer. Astrocytoma grade IV is the most frequent and most malignant primary brain tumor in adults without any curative treatment. New therapeutic drugs are therefore urgently required. In the present study, we investigated the in vitro antitumor activity of the glycosylated isothiocyanate moringin [4-(α-l-rhamnopyranosyloxy)benzyl isothiocyanate] produced from quantitative myrosinase-induced hydrolysis of glucomoringin (GMG) under neutral pH value. We have evaluated the potency of moringin on apoptosis induction and cell death in human astrocytoma grade IV CCF-STTG1 cells. Moringin showed to be effective in inducing apoptosis through p53 and Bax activation and Bcl-2 inhibition. In addition, oxidative stress related Nrf2 transcription factor and its upstream regulator CK2 alpha expressions were modulated at higher doses, which indicated the involvement of oxidative stress-mediated apoptosis induced by moringin. Moreover, significant reduction in 5S rRNA was noticed with moringin treatment. Our in vitro results demonstrated the antitumor efficacy of moringin derived from myrosinase-hydrolysis of GMG in human malignant astrocytoma cells.

The anti-proliferative effects and mechanisms of low molecular weight scorpion BmK venom peptides on human hepatoma and cervical carcinoma cells in vitro.

Peptides from scorpion venom have been previously studied for use in the prevention and treatment of various types of cancer in folk medicine. The present study investigated the anti-proliferative effects and mechanisms of the low molecular weight (~3 kDa) BmK scorpion venom peptides (LMWSVP) on human hepatoma (SMMC 7721) and cervical carcinoma (HeLa) cells. The data indicated that LMWSVP inhibited the growth of SMMC 7721 cells, but had no effect on the growth of HeLa cells. SMMC 7721 cells were more sensitive, with a higher affinity, to LMWSVP as compared with HeLa cells. In addition, LMWSVP induced apoptosis of SMMC 7721 cells by upregulating the expression of caspase-3 and downregulating the expression of Bcl-2. These data provide an experimental basis for further purification and application of LMWSVP for use as an anti-tumor drug in clinical trials.