Anti-tumor effect of polysaccharide from Hirsutella sinensis on human non-small cell lung cancer and nude mice through intrinsic mitochondrial pathway

Effect of Flammulina velutipes polysaccharide on mitochondrial apoptosis in lung adenocarcinoma A549 cells

FVP is a polysaccharide extracted from Flammulina velutipes with immunomodulatory, anti-tumor, and anti-oxidation activities. In this study, we obtained the crude polysaccharide FVP-C from the water extract of Flammulina velutipes, and its main component FVP-S1 was obtained after further purification. Upon structural identification, we found that FVP-C is a neutral polysaccharide, and FVP-S1 was an acidic golden mushroom polysaccharide, consisting of glucuronic acid, xylose, and glucose. Lung adenocarcinoma (A549) was treated with FVP-S1 and FVP-C, respectively, and we found that FVP-S1 and FVP-C inhibited the proliferation and migration ability of tumor cells, as well as changed the morphology of the tumor cells and caused chromosome sheteropythosis, among which FVP-S1 had the best inhibition effect. The results of flow cytometry experiments and mitochondrial membrane potential, RT-qPCR, and Western blot showed that FVP-S1 and FVP-C were able to decrease the mitochondrial membrane potential, increase the expression level of apoptotic proteins Casepase-3 and Casepase-9 proteins, and at the same time, increase the ratio of Bax and Bcl-2, which promoted apoptosis of tumor cells. In conclusion, these data indicated that FVP-S1 and FVP-C were able to induce apoptosis in A549 cells through the mitochondrial pathway, which played an important role in inhibiting tumor cells.

The function and application of edible fungal polysaccharides

Edible fungi, commonly known as mushrooms, are precious medicinal and edible homologous gifts from nature to us. Edible fungal polysaccharides (EFPs) are a variety of bioactive macromolecular which isolated from fruiting bodies, mycelia or fermentation broths of edible or medicinal fungus. Increasing researches have confirmed that EFPs possess multiple biological activities both in vitro and in vivo settings, including antioxidant, antiviral, anti-inflammatory, immunomodulatory, anti-tumor, hypoglycemic, hypolipidemic, and regulating intestinal flora activities. As a result, they have emerged as a prominent focus in the healthcare, pharmaceutical, and cosmetic industries. Fungal EFPs have safe, non-toxic, biodegradable, and biocompatible properties with low immunogenicity, bioadhesion ability, and antibacterial activities, presenting diverse potential applications in the food industries, cosmetic, biomedical, packaging, and new materials. Moreover, varying raw materials, extraction, purification, chemical modification methods, and culture conditions can result in variances in the structure and biological activities of EFPs. The purpose of this review is to provide comprehensively and systematically organized information on the structure, modification, biological activities, and potential applications of EFPs to support their therapeutic effects and health functions. This review provides new insights and a theoretical basis for prospective investigations and advancements in EFPs in fields such as medicine, food, and new materials.

Corrigendum: Immunomodulatory function and anti-tumor mechanism of natural polysaccharides: a review

[This corrects the article DOI: 10.3389/fimmu.2023.1147641.].

Harnessing natural product polysaccharides against lung cancer and revisit its novel mechanism

The incidence and mortality of lung cancer are on the rise worldwide. However, the benefit of clinical treatment in lung cancer is limited. Owning to important sources of drug development, natural products have received constant attention around the world. Main ingredient polysaccharides in natural products have been found to have various activities in pharmacological research. In recent years, more and more scientists are looking for the effects and mechanisms of different natural product polysaccharides on lung cancer. In this review, we focus on the following aspects: First, natural product polysaccharides have been discovered to directly suppress the growth of lung cancer cells, which can be effective in limiting tumor progression. Additionally, polysaccharides have been considered to enhance immune function, which can play a pivotal role in fighting lung cancer. Lastly, polysaccharides can improve the efficacy of drugs in lung cancer treatment by regulating the gut microbiota. Overall, the research of natural product polysaccharides in the treatment of lung cancer is a promising area that has the potential to lead to new clinical treatments. With better understanding, natural product polysaccharides have the potential to become important components of future lung cancer treatments.

Hirsutella sinensis mycelium polysaccharides attenuate the TGF-β1-induced epithelial-mesenchymal transition in human intrahepatic bile duct epithelial cells

Hirsutella sinensis is the anamorph of Ophiocordyceps sinensis, and its mycelia has been used to effectively treat a variety of hepatobiliary diseases in clinical practice. In the present study, we performed a systematic study on the composition and structure of its polysaccharides, and then employed a TGF-β1-induced human intrahepatic bile duct epithelial cell-epithelial-mesenchymal transition (HIBEC-EMT) model to investigate their effects on treating primary biliary cholangitis (PBC) based on hepatic bile duct fibrosis. Four polysaccharide fractions were obtained from H. sinensis mycelia by hot-water extraction, DEAE-cellulose column and gradient ethanol precipitation separation. HSWP-1a was an α-(1,4)-D-glucan; HSWP-1b and HSWP-1d mainly consisted of mannoglucans with a backbone composed of 1,4-linked α-D-Glcp and 1,4,6-linked α-D-Manp residues branched at O-6 of the 1,4-linked α-D-Glcp with a 1-linked α-D-Glcp as a side chain; and HSWP-1c mainly contained galactomannoglucans. These polysaccharide fractions protected HIBECs from a TGF-β1-induced EMT, according to HIBEC morphological changes, cell viability, decreased E-cadherin and ZO-1 expression, and increased vimentin and collagen I expression. Furthermore, the effects of the polysaccharides might be mediated by inhibiting the activation of the TGF-β/Smad signaling pathway, which attenuated hepatic bile duct fibrosis and potential PBC effects.

Polysaccharide-Based Stimulus-Responsive Nanomedicines for Combination Cancer Immunotherapy

Cancer immunotherapy is a promising antitumor approach, whereas nontherapeutic side effects, tumor microenvironment (TME) intricacy, and low tumor immunogenicity limit its therapeutic efficacy. In recent years, combination immunotherapy with other therapies has been proven to considerably increase antitumor efficacy. However, achieving codelivery of the drugs to the tumor site remains a major challenge. Stimulus-responsive nanodelivery systems show controlled drug delivery and precise drug release. Polysaccharides, a family of potential biomaterials, are widely used in the development of stimulus-responsive nanomedicines due to their unique physicochemical properties, biocompatibility, and modifiability. Here, the antitumor activity of polysaccharides and several combined immunotherapy strategies (e.g., immunotherapy combined with chemotherapy, photodynamic therapy, or photothermal therapy) are summarized. More importantly, the recent progress of polysaccharide-based stimulus-responsive nanomedicines for combination cancer immunotherapy is discussed, with the focus on construction of nanomedicine, targeted delivery, drug release, and enhanced antitumor effects. Finally, the limitations and application prospects of this new field are discussed.

Immunomodulatory function and anti-tumor mechanism of natural polysaccharides: A review

Polysaccharides extracted from natural resources have attracted extensive attention in biomedical research and pharmaceutical fields, due to their medical values in anti-tumor, immunomodulation, drug delivery, and many other aspects. At present, a variety of natural polysaccharides have been developed as adjuvant drugs in clinical application. Benefit from their structural variability, polysaccharides have great potential in regulating cellular signals. Some polysaccharides exert direct anti-tumor effects by inducing cell cycle arrest and apoptosis, while the majority of polysaccharides can regulate the host immune system and indirectly inhibit tumors by activating either non-specific or specific immune responses. As the essential of microenvironment in the process of tumor development has been gradually revealed, some polysaccharides were found to inhibit the proliferation and metastasis of tumor cells via tumoral niche modulation. Here, we focused on natural polysaccharides with biomedical application potential, reviewed the recent advancement in their immunomodulation function and highlighted the importance of their signaling transduction feature for the antitumor drug development.

Selenium-Modified Chitosan Induces HepG2 Cell Apoptosis and Differential Protein Analysis

INTRODUCTION

Chitosan is the product of the natural polysaccharide chitin removing part of the acetyl group, and exhibits various physiological and bioactive functions. Selenium modification has been proved to further enhance the chitosan bioactivities, and has been a hot topic recently.

METHODS

The present study aimed to investigate the potential inhibitory mechanism of selenium-modified chitosan (SMC) on HepG2 cells through MTT assays, morphological observation, annexin V-FITC/PI double staining, mitochondrial membrane potential determination, cell-cycle detection, Western blotting, and two-dimensional gel electrophoresis (2-DE).

RESULTS

The results indicated that SMC can induce HepG2 cell apoptosis with the cell cycle arrested in the S and G2/M phases and gradual disruption of mitochondrial membrane potential, reduce the expression of Bcl2, and improve the expression of Bax, cytochrome C, cleaved caspase 9, and cleaved caspase 3. Also, 2-DE results showed that tubulin α1 B chain, myosin regulatory light chain 12A, calmodulin, UPF0568 protein chromosome 14 open reading frame 166, and the cytochrome C oxidase subunit 5B of HepG2 cells were downregulated in HepG2 cells after SMC treatment.

DISCUSSION

These data suggested that HepG2 cells induced apoptosis after SMC treatment via blocking the cell cycle in the S and G2/M phases, which might be mediated through the mitochondrial apoptotic pathway. These results could be of benefit to future practical applications of SMC in the food and drug fields.

Identification of a novel mechanism for reversal of doxorubicin-induced chemotherapy resistance by TXNIP in triple-negative breast cancer via promoting reactive oxygen-mediated DNA damage

Given that triple-negative breast cancer (TNBC) lacks specific receptors (estrogen and progesterone receptors and human epidermal growth factor receptor 2) and cannot be treated with endocrine therapy, chemotherapy has remained the mainstay of treatment. Drug resistance is reportedly the main obstacle to the clinical use of doxorubicin (DOX) in this patient population. Accordingly, screening molecules related to chemoresistance and studying their specific mechanisms has clinical significance for improving the efficacy of chemotherapy in TNBC patients. Thioredoxin-interacting protein (TXNIP) is a metabolism-related protein that plays a tumor suppressor role in various malignant tumors; however, the specific role of TXNIP in tumor chemoresistance has not been reported. In the present study, we explored the potential molecular mechanism of TXNIP in the chemoresistance of TNBC for the first time. The results showed that TXNIP inhibited the proliferation of TNBC drug-resistant cells and promoted apoptosis in vitro and in vivo. Furthermore, TXNIP promoted the synthesis of reactive oxygen species (ROS) and the accumulation of DNA damage caused by DOX and increased γ-H2AX levels in a time and dose-dependent manner. Moreover, ROS scavenger pretreatment could block DNA damage induced by TXNIP and restore the resistance of TNBC resistant cells to DOX to a certain extent. In addition, we found that the small molecule c-Myc inhibitor 10058-F4 promoted TXNIP expression, increased ROS synthesis in cells, and could enhance the cytotoxicity of chemotherapy drugs in vitro and in vivo when combined with DOX. These results indicated that c-Myc inhibitor 10058-F4 could induce TXNIP upregulation in TNBC drug-resistant cells, and the upregulated TXNIP increased the accumulation of ROS-dependent DNA damage, thereby decreasing chemotherapy resistance of TNBC. Our findings reveal a new mechanism of mediating drug resistance and provide a new drug combination strategy to overcome DOX resistance in TNBC.

Separation, Purification, Structural Characterization, and Anticancer Activity of a Novel Exopolysaccharide from Mucor sp

Mucor sp. has a wide range of applications in the food fermentation industry. In this study, a novel exopolysaccharide, labeled MSEPS, was separated from Mucor sp. fermentation broth through ethanol precipitation and was purified by ion-exchange chromatography, as well as gel filtration column chromatography. MSEPS was composed mostly of mannose, galactose, fucose, arabinose, and glucose with a molar ratio of 0.466:0.169:0.139:0.126:0.015 and had a molecular weight of 7.78 × 10⁴ Da. The analysis of methylation and nuclear magnetic resonance results indicated that MSEPS mainly consisted of a backbone of →3,6)-α-d-Manp-(1→3,6)-β-d-Galp-(1→, with substitution at O-3 of →6)-α-d-Manp-(1→ and →6)-β-d-Galp-(1→ by terminal α-l-Araf residues. MTT assays showed that MSEPS was nontoxic in normal cells (HK-2 cells) and inhibited the proliferation of carcinoma cells (SGC-7901 cells). Additionally, morphological analysis and flow cytometry experiments indicated that MSEPS promoted SGC-7901 cell death via apoptosis. Therefore, MSEPS from Mucor sp. can be developed as a potential antitumor agent.

Andrographolide inhibits non-small cell lung cancer cell proliferation through the activation of the mitochondrial apoptosis pathway and by reprogramming host glucose metabolism

Background

The main aim of this research was to explore the role and mechanism of Andrographolide (Andro) in controlling non-small cell lung cancer (NSCLC) cell proliferation.

Methods

Human NSCLC H1975 cells were treated with Andro (0–20 µM) for 4–72 h. B-cell leukemia/lymphoma 2 (Bcl-2)-antagonist/killer (Bak)-small interfering RNA (siRNA) (Bak-siRNA) and fructose-1,6-bisphosphatase (FBP1)-siRNA were transfected into H1975 cells to inhibit the endogenic Bak and FBP1 expression, respectively, and their expressions were detected by real-time quantitative reverse transcription–polymerase chain reaction (qRT-PCR) and western blotting (WB). Cellular proliferation ability was determined through various assessments, including 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), colony formation, and cell counting kit-8 (CCK-8) assays. Cell apoptosis ability was measured using flow cytometry. Pro-apoptotic-related proteins (cleaved caspase 9, cleaved caspase 8, and cleaved caspase 3) and mitochondrial apoptosis pathway proteins [Bcl2-associated X (Bax), Bak, Bcl-2, and cytochrome C (cyto C)] were assessed by WB. Aerobic glycolysis-associated genes [pyruvate kinase M2 (PKM2), lactate dehydrogenase A (LDHA), and glucose transporter 1 (GLUT1)] and gluconeogenesis genes [phosphoenolpyruvate carboxykinase 1 (PEPCK1), fructose-1,6-bisphosphatase 1 (FBP1), and phosphofructokinase (PFK)] were measured by qRT-PCR. The mitochondrial membrane depolarization sensor, 5, 50, 6, 60-tetrachloro-1, 10, 3, 30 tetraethyl benzimidazolo carbocyanine iodide (JC-1) assay was used for the measurement of mitochondrial membrane potential (ΔΨm). Additionally, glycolytic metabolism, lactate production, and adenosine triphosphate (ATP) synthesis were also analyzed.

Results

Andro inhibited human NSCLC cellular proliferation and induced apoptosis in a dose-time or dose-dependent manner via activation of the mitochondrial apoptosis pathway. Andro inhibited glycolysis, promoted the gluconeogenesis pathway, and increased the levels of cleaved caspase 9, cleaved caspase 8, cleaved caspase 3, Bax, Bak, PEPCK1, FBP1, and PFK, and decreased the levels of Bcl-2, PKM2, LDHA, and GLUT1. Moreover, it also decreased the ΔΨm and facilitated the release of cyto C from mitochondria into the cytoplasm. Furthermore, Andro enhanced the mitochondrial translocation of Bak, glucose uptake, lactate release, and intracellular ATP synthesis. Suppression of endogenic Bak and FBP1 expression significantly reduced the effects of Andro in H1975 cells.

Conclusions

Andro represses NSCLC cell proliferation through the activation of the mitochondrial apoptosis pathway and by reprogramming glucose metabolism.

Advances in the regulation of natural polysaccharides on human health: The role of apoptosis/autophagy pathway

Due to the multiple biological activities of polysaccharides, their great potential as "natural drugs" for many diseases has been the subject of continuous exploration in the field of food and nutrition. Apoptosis and autophagy play a key role in mammalian growth, development and maintenance of cellular homeostasis. Recent studies suggest that apoptosis/autophagy may be the key regulatory target for the beneficial effects of polysaccharides. However, the regulation of apoptosis and autophagy by polysaccharides is not consistent in different disease models. Therefore, this review outlined the relationship between apoptosis/autophagy and some common human diseases, then discussed the role of apoptosis/autophagy pathway in the regulation of human health by polysaccharides, Furthermore, the application of visualization, imaging and multi-omics techniques was proposed in the future trend. The present review may be beneficial to accelerate our understanding of the anti-disease mechanisms of polysaccharides, and promote the development and utilization of polysaccharides.

The Role of Reactive Oxygen Species in Tumor Treatment and its Impact on Bone Marrow Hematopoiesis

Reactive oxygen species (ROS), an important molecule inducing oxidative stress in organisms, play a key role in tumorigenesis, tumor progression and recurrence. Recent findings on ROS have shown that ROS can be used to treat cancer as they accelerate the death of tumor cells. At present, pro-oxidant drugs that are intended to increase ROS levels of the tumor cells have been widely used in the clinic. However, ROS are a double-edged sword in the treatment of tumors. High levels of ROS induce not only the death of tumor cells but also oxidative damage to normal cells, especially bone marrow hemopoietic cells, which leads to bone marrow suppression and (or) other side effects, weak efficacy of tumor treatment and even threatening patients' life. How to enhance the killing effect of ROS on tumor cells while avoiding oxidative damage to the normal cells has become an urgent issue. This study is a review of the latest progress in the role of ROS-mediated programmed death in tumor treatment and prevention and treatment of oxidative damage in bone marrow induced by ROS.

Hirsutella Sinensis Fungus Regulates CD8+ T Cell Exhaustion Through Involvement of T-Bet/Eomes in the Tumor Microenvironment

Background: Targeting exhausted T (Tex) cells is a promising strategy for anti-tumour treatment. Previously, we demonstrated that Hirsutella sinensis fungus (HSF) could significantly increase T cell infiltration and the effector T cell ratio in the tumor microenvironment, activating systemic immune responses. However, we do not know how HSF regulates Tex cells in the tumor microenvironment. Here, we explored the mechanism underlying HSF inhibition of Tex cells and tumor growth and metastasis in breast cancer. Methods: We examined the effects of HSF on various tumor mouse models using in vivo imaging technology. Lung metastasis was detected by H&E staining and the T cell subsets in the tumor microenvironment were assayed with flow cytometry. The in vitro proliferation, function and apoptosis of CD8⁺ T cells were measured, as well as the T-bet and PD-1 mRNA expressions. Results: HSF inhibited tumor growth and lung metastasis in the mice, and had significantly higher CD44^LowCD62L^Hi and CD44^HiCD62L^Lowpopulations in the tumour-infiltrating CD8⁺ T cells. However, HSF significantly reduced levels of inhibitory receptors, such as PD-1, TIGIT, CTLA-4, and regulatory T cells. In vitro, HSF inhibited the CD8⁺ T cell apoptosis rate, and promoted CD8⁺ T cell proliferation and secretion of interferon (IFN)-γ and granzyme B. Furthermore, HSF treatment both in vivo and in vitro significantly increased Eomes expression, while decreasing T-bet expression. Conclusion: HSF exerted anti-tumour effects mainly through the immune system, by promoting effector/memory T cells and reducing Tex cell production in the tumor microenvironment. The specific mechanisms involved inhibiting T-bet and promoting Eomes to decrease the expression of immune inhibitor receptors and enhance the T cell function, respectively.

Ganoderma triterpenoids attenuate tumour angiogenesis in lung cancer tumour-bearing nude mice

CONTEXT

Ganoderma lucidum (Leyss. ex Fr.) Karst. (Polyporaceae) triterpenoids (GLTs), the main components and bioactive metabolites of G. lucidum, have antitumour activity.

OBJECTIVE

We investigated the effects of GLTs in lung cancer tumour-bearing nude mice and their potential mechanism.

MATERIALS AND METHODS

Forty BALB/c nude mice were randomly divided into four groups: saline control, GLT (1 g/kg/day), gefitinib (GEF, 15 mg/kg/day), and GLT (1 g/kg/day) + GEF (15 mg/kg/day) for 14 days. Cell viability was conducted using the Cell Counting Kit-8 assay. The tumour volume, inhibition rate, histopathological, microvessel density (MVD), mRNAs, and proteins were determined.

RESULTS

GLTs inhibited the cell viability of A549 cells with an IC₅₀ value of 14.38 ± 0.29 mg/L, while the IC₅₀ value of GEF was 10.26 ± 0.47 μmol/L. The tumour inhibition rate in the GLT + GEF group (51.54%) was significantly decreased relative to the saline control… group (p < 0.05). The MVD in the GLT + GEF group (2.9 ± 0.7) was significantly decreased than that in the saline control group (12.8 ± 1.4, p < 0.05). The angiostatin, endostatin, and Bax protein expression in the GLT, GEF, and GLT + GEF groups were significantly increased compared to those in the saline control group, while the VEGFR2 and Bcl-2 protein expression were decreased.

DISCUSSION AND CONCLUSIONS

Our study provided evidence that GLT and GEF combination therapy may be a promising candidate for the treatment of lung cancer and as an experimental basis for clinical treatment.

Occurrence and possible roles of polysaccharides in fungi and their influence on the development of new technologies

The article summarizes the roles of polysaccharides in the biology of fungi and their relationship in the development of new technologies. The comparative approach between the evolution of fungi and the chemistry of glycobiology elucidated relevant aspects about the role of polysaccharides in fungi. Also, based on the knowledge of fungal glycobiology, it was possible to address the development of new technologies, such as the production of new anti-tumor drugs, vaccines, biomaterials, and applications in the field of robotics. We conclude that polysaccharides activate pathways of apoptosis, secretion of pro-inflammatory substances, and macrophage, inducing anticancer activity. Also, the activation of the immune system, which opens the way for the production of vaccines. The development of biomaterials and parts for robotics is a promising and little-explored field. Finally, the article is multidisciplinary, with a different and integrated approach to the role of nature in the sustainable development of new technologies.

TEOA Inhibits Proliferation and Induces DNA Damage of Diffuse Large B-Cell Lymphoma Cells Through Activation of the ROS-Dependent p38 MAPK Signaling Pathway

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of lymphoma, accounting for approximately 30% to 40% of non-Hodgkin’s lymphomas (NHL). The administration of rituximab significantly improved the outcomes of DLBCL; however, the unavoidable development of resistance limits the long-term efficacy. Therefore, a new generation of less toxic drugs with higher chemotherapy response is required to prevent or reverse chemoresistance. TEOA is a pentacyclic triterpenoid compound isolated from the roots of Actinidia eriantha. Studies have confirmed that TEOA has significant cytotoxicity on gastrointestinal cancer cells. However, there are no relevant reports on DLBCL cells. In this study, we investigated the potential molecular mechanism of the anticancer activity of TEOA in DLBCL cells. The results demonstrated that TEOA inhibited proliferation and induced apoptosis in time-and dose-dependent manners. TEOA induced reactive oxygen species (ROS) generation, which was reversed by N-acetyl cysteine (NAC). TEOA induced DNA damage, increased the level of γ-H2AX, and the phosphorylation of CHK1 and CHK2. In addition, TEOA induced the activation of the p38 MAPK pathway and pretreated with p38 inhibitor SB20358 or ROS scavenger could block TEOA-induced DNA damage. Taken together, these results suggest that ROS mediated activation of the p38 MAPK signal pathway plays an important role in initiating TEOA-induced DNA damage.

Purification, characterization and anti-tumor activities of polysaccharides from Ecklonia kurome obtained by three different extraction methods

To investigate and compare the effects of different extraction methods on the structure and anti-tumor activity of Ecklonia kurome polysaccharides (EP), three techniques, namely hot water extraction (HW), ultrasonic-assisted extraction (UA) and enzyme-assisted extraction (EA), were used to extract EP, and three crude EPs were purified by DEAE-cellulose and gel filtration chromatography. The significant antitumor active components in each method were screened by MTT assay and named as HW-EP5, UA-EP4 and EA-EP3, respectively. The molecular weight, FT-IR assay and NMR showed that HW-EP5, UA-EP4 and EA-EP3 were pyran polysaccharides with a molecular weight of 14,466, 15,922 and 16,947 Da, respectively. HW-EP5 contained the most monosaccharides and the highest content of sulfate and uronic acid. HW-EP5 had an even and smooth sheet-like appearance, while UA-EP4 and EA-EP3 exhibited irregular and rough fragments. All three polysaccharides can inhibit the migration of human breast cancer cells (MCF-7) and promote its apoptosis. All three polysaccharides promoted caspase activity during apoptosis. HW-EP5 and UA-EP4 up-regulated the expression of proapoptotic proteins Bax and p53, while EA-EP3 only up-regulated the expression of p53. These experimental results indicate that Ecklonia kurome polysaccharides, especially HW-EP5, have great potential as a natural medicine for the treatment of breast cancer.

Knockdown of PLAT enhances the anticancer effect of gefitinib in non-small cell lung cancer

Background

Tyrosine kinase inhibitors (TKIs), such as gefitinib, are widely used as standard treatments for non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations. However, the subsequent inevitable drug resistance has become a major challenge in clinical treatment. The aim of this study was to investigate the role of tissue-type plasminogen activator (PLAT) in gefitinib resistance in NSCLC.

Methods

The function of PLAT was determined using gefitinib-resistant cells and a nude mouse model. The gene knockdown was achieved by Lentivirus based RNA silence technique. Expression of relevant genes and proteins, cell viability, proliferation, apoptosis, cell cycle, reactive oxygen species levels, mitochondrial membrane potential and differential gene expression was detected by RT-qPCR, western blot, cell counting kit-8 assay, EdU incorporation, flow cytometry, JC-1 dye assay and complementary DNA arrays. The effects of PLAT knockdown on tumorigenesis was analyzed in vivo.

Results

Gefitinib-resistant cells expressed higher levels of PLAT and that knockdown of PLAT in resistant cells restored gefitinib sensitivity. Tumor proliferation was limited in vivo following PLAT knockdown. Moreover, PLAT knockdown affected mitochondrial function, caused caspase activation and cell cycle arrest, and activated TNF-α signaling, leading to apoptosis of gefitinib-resistant PC9 cells.

Conclusions

Our results suggest that PLAT reduces apoptosis of NSCLC cells and knockdown of PLAT enhances anticancer effect of gefitinib by upregulating TNF-α signaling.

Antitumor effects of seleno-short-chain chitosan (SSCC) against human gastric cancer BGC-823 cells

Seleno-short-chain chitosan (SSCC) is a derivative of chitosan. In the present study, we sought to investigate the underlying antitumor mechanism of SSCC on human gastric cancer BGC-823 cells in vitro. MTT assay suggested that SSCC exhibited a dose-dependent inhibitory effect on the proliferation of BGC-823 cells. We found the SSCC-treated cells showed typical morphological characteristics of apoptosis in a dose dependent manner by observing on microscope. Annexin V-FITC/PI double staining and cell cycle assay identified that SSCC could induce BGC-823 cells apoptosis by triggering G2/M phase arrest. Our research provided the first evidence that SSCC could effectively induce the apoptosis of BGC-823 cells via an intrinsic mitochondrial pathway, as indicated by inducing the disruption of mitochondrial membrane potential (MMP), the excessive accumulation of reactive oxidative species (ROS), the increase of Bax/Bcl-2 ratio and the activation of caspase 3, caspase 9 and cytochrome C (Cyt-C) in BGC-823 cells. These combined results clearly indicated that SSCC could induce BGC-823 cells apoptosis by the involvement of mitochondrial signaling pathway, which provided precise experimental evidence for SSCC as a potential agent in the prevention and treatment of human gastric cancer.

Induction of cell-cycle arrest and apoptosis in human cholangiocarcinoma cells by pristimerin

Pristimerin, a triterpenoid isolated from Celastraceae and Hippocrateaceae, is known to induce cytotoxicity in several cancer cell lines. However, whether pristimerin can induce apoptosis in cholangiocarcinoma cells and the underlying mechanism remain unexplored. We assessed the function of human cholangiocarcinoma QBC and RBE cell lines using various experimental methods such as the cell viability assay to elucidate the viability of cells, flow cytometry to detect the death rate of cells, and Western blot analysis to evaluate the expression of cell cycle-related proteins and autophagy-related proteins. Human cholangiocarcinoma QBC cells were transplanted to nude mice to establish an animal model, and the effect of pristimerin on tumor growth in this model was observed. QBC and RBE cell lines treated with pristimerin (0, 5, 10, and 20 μmol/L) demonstrated the induction of apoptosis in a dose-dependent manner. The cell viability assay revealed a reduction in the cell viability with an increase in the pristimerin concentration. Similarly, flow cytometry revealed a gradual increase in the cell death rate with an increase in the pristimerin concentration. In addition, pristimerin significantly lowered the expression of apoptosis-related proteins (Bcl-2, Bcl-xL, and procaspase-3), but increased the Bax expression. Furthermore, pristimerin resulted in the G0/G1 cell-cycle arrest, reducing the expression of cell cycle-related proteins (cyclin E, CDK2, and CDK4), and increased the expression of autophagy-related proteins (LC3) in QBC cell line. Treatment with pristimerin could inhibit tumor growth in the nude mouse model. Overall, this study suggests the potential effect of pristimerin on the cell-cycle arrest and apoptosis in human cholangiocarcinoma cells.

A Novel Animal Model of Induced Breast Precancerous Lesion in Tree Shrew

Chinese tree shrew, an animal exhibited closer evolutionary relationship with humans compared to rodents, is getting increasingly attentions as an appealing experimental animal model for human diseases. However, a high-efficiency and stable method to establish tree shrew breast precancerous lesions model has not been clearly elucidated. Thus, the current study aimed to explore the way of establishing breast precancerous model in tree shrew and investigate the pathologic characteristics of induced breast precancerous lesions. The results indicated that 7,12-dimethylbenz(a)anthracene (DMBA) could induce breast lesions in tree shrews. However, comparing to DMBA alone, an addition of medroxyprogesterone acetate (MPA) to DMBA critically increased the rate of induced breast lesion in tree shrews. Half of induced breast lesions were intraductal papilloma and the others were atypical ductal hyperplasia. Induced lesions showed positive expression of estrogen receptor α (ERα), progesterone receptor (PR) and cytokeratin 5/6 (CK5/6), but negative expression of human epidermal growth factor receptor-2 (Her-2). The expression of B cell lymphoma-extra large (Bcl-xl) was significantly higher and the expression of B cell lymphoma 2 associated X protein (Bax) was significantly lower in the precancerous lesions (atypical ductal hyperplasia) compared to benign tumor (intraductal papilloma). These results suggest that DMBA is able to induce breast lesions in tree shrews. Combination of DMBA and MPA may be more effective to establish breast precancerous lesion tree shrew models. Tree shrew might be a promising animal model for studying the tumorogenesis of breast cancer.

Effects of a homogeneous polysaccharide from Sijunzi decoction on human intestinal microbes and short chain fatty acids in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Sijunzi decoction (SJZD) is a classic recipe in traditional Chinese medicine (TCM) to strengthen the spleen and replenish Qi. It is well known for treating disorders of gastrointestinal function manifested in poor appetite, reduced food intake and loose stools. Polysaccharide is the most abundant constituent and the major effective component in SJZD.

AIM OF THE STUDY

The present study aimed to understand the immunomodulatory mechanism of S-3-1, a homogeneous polysaccharide purified from SJZD with immune-enhancement activity, by investigating its effects on human intestinal microbes and short chain fatty acids.

MATERIALS AND METHODS

S-3-1 was incubated with simulated gastric juice, intestinal juice, and human fecal microflora independently and sequentially. The concentrations of total polysaccharide and reducing sugar were measured to identify the stability of independently and sequentially incubated S-3-1 in three in vitro fermentation models. Gas chromatograph (GC) analysis was used to measure the short chain fatty acid (SCFA) contents in human fecal samples. The human gut microbiota composition was measured by 16S rRNA gene Illumina MiSeq sequencing (V3-V4 region).

RESULTS

S-3-1 was degraded in three in vitro fermentation models separately and sequentially. Both S-3-1 and incubated S-3-1 could regulate the abundances of Lactobacillus, Pediococcus, Streptococcus, Bacteroides, Enterococcus, Clostridium and Dorea in human intestinal microflora samples. Specifically, S-3-1 could only regulate the abundances of Paraprevotella and Oscillospira, while the influenced flora changed to Butyricimonas, Coprococcus, Dialister, Sutterella, Ruminococcus and Parabacteroides after sequential incubation of S-3-1. In contrast to S-3-1 showing no influence on the content of SCFA, incubated S-3-1 showed increased contents of acetic acid and total acid that were associated with its effects on the abundances of Enterococcus, Sutterella, Butyricimonas and Streptococcus.

CONCLUSION

S-3-1 plays an immunomodulatory role by regulating the abundances of 9 intestinal bacteria genera. Incubated S-3-1 can regulate more bacteria genera, a total of 13 kinds, and can adjust the SCFA content to affect immunomodulation. Incubation with gastric and intestinal juices enhanced S-3-1's capability of modulating the intestinal flora composition and decreased the bacteria's need for a carbon source. This study could provide new insights for studies on the pharmacological mechanisms of polysaccharides in vitro.

Cytotoxicity of two water-soluble polysaccharides from Codonopsis pilosula Nannf. var. modesta (Nannf.) L.T.Shen against human hepatocellular carcinoma HepG2 cells and its mechanism

Two water-soluble polysaccharides named CPP1a and CPP1c were isolated from C. pilosula Nannf. var. modesta L.T.Shen by hot-water extraction and purified by graded alcohol precipitation and DEAE-52 cellulose column. The structure of CPP1c with higher yield has been characterized while its antitumor activities has not been elucidated. In this study, we firstly analyzed the chemical structure of CPP1a. The results of instrumental analysis combined with chemical analysis showed that CPP1a was composed of →1)- β‑l‑Rhap‑(4→, →1)- β‑Arap‑(5→, →1)- β‑d‑GalpA‑(4→, →1)- β‑d‑Galp‑(6→, terminal‑β‑d‑Glcp in a molar ratio of 1:12:1:10:3 and its relative and absolute molecular weight were 1.01 × 10⁵ Da and 1.03 × 10⁵ Da respectively. Further, the cytotoxicity assay indicated that CPP1a and CPP1c were more sensitive to HepG2 cells than cervical carcinoma Hela cells and gastric carcinoma MKN45 cells. Both of CPP1a and CPP1c could influence cell morphology, inhibit the migration and induce apoptosis by affecting the G2/M phase of HepG2 cells. Preliminary mechanism studies confirmed that CPP1a and CPP1c could induce apoptosis through up-regulating the ratio of Bax/Bcl-2 and activating caspase-3. According to previous research, we might speculate that the reason for the stronger cytotoxicity and pro-apoptotic effect of CPP1c than that of CPP1a can be attributed to its high uronic acid content.

Seleno-short-chain chitosan induces apoptosis in human breast cancer cells through mitochondrial apoptosis pathway in vitro

Seleno-short-chain chitosan (SSCC) was a synthesized chitosan derivative with the molecular weight of 4826.986 Da. The study is aimed to investigate cytotoxicity of SSCC on human breast cancer MCF-7 and BT-20 cells and explore apoptosis-related mechanism in vitro. The MTT (3- [4,5-Dimethylthiazol-2-yl]-2, 5-diphenylterazolium bromide) assay showed that SSCC exhibited significantly cytotoxic effects on MCF-7 and BT-20 cells in a dose- and time-dependent manner, and the effective inhibitory concentration was 100 μg/ml and 200 μg/ml, respectively. Apoptosis assay of these two kinds of cells was determined by Hoechst 33,342/PI and Annexin V-FITC/PI double staining. The cell cycle assay showed that SSCC triggered S and G2/M phase cell cycle arrest in MCF-7 cells and S phase cell cycle arrest in BT-20 cells in a time-dependent manner. Further studies demonstrated that SSCC led to the generation of reactive oxygen species (ROS) and the disruption of mitochondrial membrane potential (MMP) in these two kinds of cells. N- acetyl-L cysteine (NAC), as a radical scavenger, significantly inhibited the generation of ROS and decreased the apoptosis of MCF-7 and BT-20 cells. Moreover, the expression of mitochondrial apoptosis-related proteins was detected by western blot assay. SSCC up-regulated the expression of Bax, down-regulated the expression of Bcl-2, subsequently increased the release of cytochrome c from mitochondria to cytoplasm, and activated the cleavage of caspase-9 and -3, which finally induced apoptosis in MCF-7 and BT-20 cells in vitro. Consequently, these data indicated that SSCC could induce apoptosis of MCF-7and BT-20 cells in vitro by mitochondrial pathway.

Dose matters: Direct killing or immunoregulatory effects of natural polysaccharides in cancer treatment

Polysaccharides from natural resources possess anti-tumor activities for decades, but the efficacy of polysaccharides as the adjuvant drugs for cancer treatment at prescribed doses remains open for debate. In this review, molecular mechanisms involved in direct killing effects of polysaccharides, including apoptosis, cell cycle arrest and mitochondria/DNA damage were described. However, the concentrations/doses used to reach the direct killing effects are too high to be applicable. Polysaccharides can also exert anti-tumor effects through immunoregulation at lower doses, and the effects of polysaccharides on natural killer cells, dendritic cells and other lymphocytes for tumor destruction, along with the receptor recognition and downstream signaling pathways, were delineated. Unfortunately, the prescribed doses of polysaccharides are too low to stimulate immunoresponse, resulting in the failure of some clinical trials. Therefore, understanding the sophisticated mechanisms of the immunoregulatory function of natural polysaccharides with refined doses for clinical use will help the standardization of traditional medicine.