Inhibition of autophagy promotes apoptosis and enhances anticancer efficacy of adriamycin via augmented ROS generation in prostate cancer cells

A novel glycoglycerolipid from Holotrichia diomphalia Bates: Structure characteristics and protective effect against DNA damage

A lipidated polysaccharide, HDPS-2II, was isolated from the dried larva of Holotrichia diomphalia, which is used in traditional Chinese medicine. The molecular weight of HDPS-2II was 5.9 kDa, which contained a polysaccharide backbone of →4)-β-Manp-(1 → 4,6)-β-Manp-(1 → [6)-α-Glcp-(1]n → 6)-α-Glcp→ with the side chain α-Glcp-(6 → 1)-α-Glcp-(6 → linked to the C-4 of β-1,4,6-Manp and four types of lipid chains including 4-(4-methyl-2-(methylamino)pentanamido)pentanoic acid, 5-(3-(tert-butyl)phenoxy)hexan-2-ol, N-(3-methyl-5-oxopentan-2-yl)palmitamide, and N-(5-amino-3-methyl-5-oxopentan-2-yl)stearamide. The lipid chains were linked to C-1 of terminal α-1,6-Glcp in carbohydrate chain through diacyl-glycerol. HDPS-2II exhibited DNA protective effects and antioxidative activity on H2O2- or adriamycin (ADM)-induced Chinese hamster lung cells. Furthermore, HDPS-2II significantly ameliorated chromosome aberrations and the accumulation of reactive oxygen species (ROS), reduced γ-H2AX signaling and the expressions of NADPH oxidase (NOX)2, NOX4, P22phox, and P47phox in ADM-induced cardiomyocytes. Mechanistically, HDPS-2II suppressed ADM-induced up-regulation of NOX2 and NOX4 in cardiomyocytes, but not in NOX2 or NOX4 knocked-down cardiomyocytes, indicating that HDPS-2II could relieve intracellular DNA damage by regulating NOX2/NOX4 signaling. These findings demonstrate that HDPS-2II is a new potential DNA protective agent.

Blockade of NMT1 enzymatic activity inhibits N-myristoylation of VILIP3 protein and suppresses liver cancer progression

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. Identification of the underlying mechanism of HCC progression and exploration of new therapeutic drugs are urgently needed. Here, a compound library consisting of 419 FDA-approved drugs was taken to screen potential anticancer drugs. A series of functional assays showed that desloratadine, an antiallergic drug, can repress proliferation in HCC cell lines, cell-derived xenograft (CDX), patient-derived organoid (PDO) and patient-derived xenograft (PDX) models. N-myristoyl transferase 1 (NMT1) was identified as a target protein of desloratadine by drug affinity responsive target stability (DARTS) and surface plasmon resonance (SPR) assays. Upregulation of NMT1 expression enhanced but NMT1 knockdown suppressed tumor growth in vitro and in vivo. Metabolic labeling and mass spectrometry analyses revealed that Visinin-like protein 3 (VILIP3) was a new substrate of NMT1 in protein N-myristoylation modification, and high NMT1 or VILIP3 expression was associated with advanced stages and poor survival in HCC. Mechanistically, desloratadine binds to Asn-246 in NMT1 and inhibits its enzymatic activity, disrupting the NMT1-mediated myristoylation of the VILIP3 protein and subsequent NFκB/Bcl-2 signaling. Conclusively, this study demonstrates that desloratadine may be a novel anticancer drug and that NMT1-mediated myristoylation contributes to HCC progression and is a potential biomarker and therapeutic target in HCC.

SAR Study and Molecular Mechanism Investigation of Novel Naphthoquinone-furan-2-cyanoacryloyl Hybrids with Antitumor Activity

A series of novel naphthoquinone-furan-2-cyanoacryloyl hybrids were designed; they were synthesized and preliminarily evaluated for their anti-proliferative activities in vitro against several cancer cell lines and normal cells. The most potent compound, 5c, inhibited the proliferation of HeLa cells (IC₅₀ value of 3.10 ± 0.02 μM) and colony survival, and it induced apoptosis while having relatively weaker effects on normal cells. Compound 5c also triggered ROS generation and accumulation, thus partially contributing to the observed cell apoptosis. A Western blotting analysis demonstrated that compound 5c inhibited the phosphorylation of STAT3. Furthermore, a biolayer interferometry (BLI) analysis confirmed that compound 5c had a direct effect on STAT3, with a KD value of 13.0 μM. Molecular docking showed that 5c specifically occupied the subpockets in the SH2 domain, thereby blocking the whole transmission signaling process. Overall, this study provides an important structural reference for the development of effective antitumor agents.

Anti-tumor effects of dual PI3K-HDAC inhibitor CUDC-907 on activation of ROS-IRE1α-JNK-mediated cytotoxic autophagy in esophageal cancer

Background

PI3K-Akt pathway activation and the expression of histone deacetylases (HDACs) are highly increased in esophageal cancer, suggesting that inhibition of such targets may be a viable therapeutic strategy. Herein, we aimed to evaluate the anti-tumor effect of CUDC-907, a dual PI3K-HDAC inhibitor, in esophageal squamous cell carcinoma (ESCC).

Methods

The anti-tumor effects of CUDC-907 in ESCC were evaluated using cell counting kit-8, flow cytometry, and western blot. mRNA-sequencing was used to explore the mechanism underlying CUDC-907 anti-tumor effects. The relations of reactive oxygen species (ROS), lipocalin 2 (LCN2), and CUDC-907 were determined by flow cytometry, rescue experiments, and western blot. The activation of the IRE1α-JNK-CHOP signal cascade was confirmed by western blot. The in vivo inhibitory effects of CUDC-907 were examined by a subcutaneous xenograft model in nude mice.

Results

CUDC-907 displayed effective inhibition in the proliferation, migration, and invasion of ESCC cells. Through an mRNA-sequencing and functional enrichment analysis, autophagy was found to be associated with cancer cells death. CUDC-907 not only inhibited the PI3K-Akt-mTOR pathways to result in autophagy, but also induced ROS accumulation to activate IRE1α-JNK-CHOP-mediated cytotoxic autophagy by downregulating LCN2 expression. Consistently, the in vivo anti-tumor effects of CUDC-907 accompanied by the downregulated expression of p-mTOR and LCN2 and upregulated expression of p-IRE1α and LC3B-II were evaluated in a xenograft mouse model.

Conclusion

Our findings suggested the clinical development and administration of CUDC-907 might act as a novel treatment strategy for ESCC. A more in-depth understanding of the anti-tumor effect of CUDC-907 in ESCC will benefit the clinically targeted treatment of ESCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-022-00855-x.

SRT2183 impairs ovarian cancer by facilitating autophagy

The 5-year survival rate of ovarian cancer patients is only 47%, and developing novel drugs for ovarian cancer is needed. Herein, we evaluated if and how SRT2183, a sirtuin-1 activator, impairs the ovarian cancer cells. OVCAR-3 and A2780 cells were treated with SRT2183. Cell viability was measured by cell counting kit-8 assay and clonogenic assay. Apoptosis was determined by flow cytometry with Annexin V and propidium iodide. The level of autophagy was evaluated by western blot and immunofluorescence. The activities of AKT/mTOR/70s6k and MAPK signaling pathway were measured by immunoblot. SRT2183 inhibited the growth of ovarian cancer cells, increased the accumulation of BAX, cleaved-caspase 3 and cleaved-PARP, and decreased the level of anti-apoptotic Bcl-2 and Mcl-1. SRT2183 increased the LC3II level, and enhanced the degradation of p62/SQSTM1. SRT2183 increased the formation of GFP-LC3 puncta and induced the maturation of autophagosome. Interestingly, knockdown of autophagy related 5 and 7 significantly impaired the anti-carcinoma activity of SRT2183, implying that SRT2183 impaired the ovarian cancer cells by inducing autophagy. SRT2183 decreased the accumulation of p-Akt, p-mTOR and p-70s6k, and activated the p38 MAPK signaling pathway. This indicated that Akt/mTOR/70s6k and p38 MAPK signaling pathway might be involved in the SRT2183-mediated autophagy and apoptosis.

Costunolide Induces Autophagy and Apoptosis by Activating ROS/MAPK Signaling Pathways in Renal Cell Carcinoma

Although costunolide (Cos), a natural sesquiterpene compound isolated from various medicinal plants, exhibits antiproliferative and pro-apoptotic effects in diverse types of cancers, the mechanism associated with the anticancer property of Cos has not been elucidated. The present investigation was carried out to study the anticarcinogenic influence of Cos on kidney cancer cells. Several human renal cancer cell lines were used and biological and molecular studies were conducted. It was found that Cos significantly suppressed renal carcinoma cell growth via stimulation of apoptosis and autophagy in a concentration-dependent manner. Further studies revealed that Cos increased Bax/Bcl-2 ratio, decreased mitochondrial transmembrane potential (MMP), and enhanced cytoplasmic levels of cytochrome c, and activation of caspase-9, caspase-3, and cleaved PARP, resulting in cell apoptosis. The autophagy induced by Cos resulted from the formation of GFP-LC3 puncta and upregulation of LC3B II and Beclin-1 proteins. Compared with Cos treatment, the autophagy inhibitor 3-MA or ROS scavenger NAC significantly inhibited apoptosis and autophagy. Moreover, NAC and JNK-specific inhibitor SP600125 attenuated the effect of Cos. Taken together, Cos exerted autophagic and apoptotic effects on renal cancer through the ROS/JNK-dependent signal route. These findings suggest that Cos could be a beneficial anticarcinogenic agent.

Roles of Reactive Oxygen Species in Biological Behaviors of Prostate Cancer

Prostate cancer (PCa), known as a heterogenous disease, has a high incidence and mortality rate around the world and seriously threatens public health. As an inevitable by-product of cellular metabolism, reactive oxygen species (ROS) exhibit beneficial effects by regulating signaling cascades and homeostasis. More and more evidence highlights that PCa is closely associated with age, and high levels of ROS are driven through activation of several signaling pathways with age, which facilitate the initiation, development, and progression of PCa. Nevertheless, excessive amounts of ROS result in harmful effects, such as genotoxicity and cell death. On the other hand, PCa cells adaptively upregulate antioxidant genes to detoxify from ROS, suggesting that a subtle balance of intracellular ROS levels is required for cancer cell functions. The current review discusses the generation and biological roles of ROS in PCa and provides new strategies based on the regulation of ROS for the treatment of PCa.

A lysosome independent role for TFEB in activating DNA repair and inhibiting apoptosis in breast cancer cells

Transcription factor EB (TFEB) is a master regulator of lysosomal biogenesis and autophagy with critical roles in several cancers. Lysosomal autophagy promotes cancer survival through the degradation of toxic molecules and the maintenance of adequate nutrient supply. Doxorubicin (DOX) is the standard of care treatment for triple-negative breast cancer (TNBC); however, chemoresistance at lower doses and toxicity at higher doses limit its usefulness. By targeting pathways of survival, DOX can become an effective antitumor agent. In this study, we examined the role of TFEB in TNBC and its relationship with autophagy and DNA damage induced by DOX. In TNBC cells, TFEB was hypo-phosphorylated and localized to the nucleus upon DOX treatment. TFEB knockdown decreased the viability of TNBC cells while increasing caspase-3 dependent apoptosis. Additionally, inhibition of the TFEB-phosphatase calcineurin sensitized cells to DOX-induced apoptosis in a TFEB dependent fashion. Regulation of apoptosis by TFEB was not a consequence of altered lysosomal function, as TFEB continued to protect against apoptosis in the presence of lysosomal inhibitors. RNA-Seq analysis of MDA-MB-231 cells with TFEB silencing identified a down-regulation in cell cycle and homologous recombination genes while interferon-γ and death receptor signaling genes were up-regulated. In consequence, TFEB knockdown disrupted DNA repair following DOX, as evidenced by persistent γH2A.X detection. Together, these findings describe in TNBC a novel lysosomal independent function for TFEB in responding to DNA damage.

Inhibition of autophagy in theca cells induces CYP17A1 and PAI-1 expression via ROS/p38 and JNK signalling during the development of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a clinical syndrome characterized by hyperandrogenism, oligo/anovulation, and polycystic ovary. Autophagy is an intracellular system that degrades cytosolic proteins and organelles. The relationship between autophagy and PCOS has not been clarified. We found that p62 and ubiquitin were significantly increased in theca cells of women with PCOS using immunohistochemistry. Autophagy inhibition by palmitic acid and chloroquine in bovine theca cells increased p62 and ubiquitin and induced the expression of cytochrome P450 17A1 (CYP17A1) and plasminogen activator inhibitor-1 (PAI-1) mRNA. Furthermore, palmitic acid and chloroquine exposure significantly increased reactive oxygen species (ROS) and activated p38 and c-Jun N-terminal kinase (JNK). Inhibition of p38 and JNK significantly reduced CYP17A1 and PAI-1 mRNA expression. We showed that inhibition of autophagy in theca cells may have contributed to the pathogenesis of PCOS, based on CYP17A1 and PAI-1 mRNA expression via the ROS/p38 and JNK signalling pathways.

Molecular mechanisms of apoptosis and autophagy elicited by combined treatment with oridonin and cetuximab in laryngeal squamous cell carcinoma

Combined oridonin (ORI), a natural and safe kaurene diterpenoid isolated from Rabdosia rubescens, and cetuximab (Cet), an anti-EGFR monoclonal antibody, have been reported to exert synergistic anti-tumor effects against laryngeal squamous cell carcinoma (LSCC) both in vitro and in vivo by our group. In the present study, we further found that ORI/Cet treatment not only resulted in apoptosis but also induced autophagy. AMPK/mTOR signaling pathway was found to be involved in the activation of autophagy in ORI/Cet-treated LSCC cells, which is independent of p53 status. Additionally, chromatin immunoprecipitation (ChIP) assay showed that ORI/Cet significantly increased the binding NF-κB family member p65 with the promotor of BECN 1, and p65-mediated up-regulation of BECN 1 caused by ORI/Cet is coupled to increased autophagy. On the other hand, we demonstrated that either Beclin 1 SiRNA or autophagy inhibitors could increase ORI/Cet induced-apoptosis, indicating that autophagy induced by combination of the two agents plays a cytoprotective role. Interestingly, 48 h after the combined treatment, autophagy began to decrease but apoptosis was significantly elevated. Our findings suggest that autophagy might be strongly associated with the antitumor efficacy of ORI/Cet, which may be beneficial to the clinical application of ORI/Cet in LSCC treatment.

Elevated SRC3 expression predicts pemetrexed resistance in lung adenocarcinoma

Lung cancer has been the leading cause of cancer-related death for many years worldwide. Pemetrexed, either as monotherapy or combined with other agents, is the preferred chemotherapy regimen for lung adenocarcinoma. However, both de novo and acquired resistance against pemetrexed frequently occur and lead to poor prognosis of patients. The underlying mechanisms remain poorly characterized. Here, RNA-seq analysis is utilized to compare gene expression levels in an adenocarcinoma cell line A549 with those in its pemetrexed-resistant counterpart, A549/PEM. We show that SRC3 is one of the most significantly upregulated genes in pemetrexed-resistant cells. SRC3 specifically enhances pemetrexed resistance in cultured adenocarcinoma cells. In addition, SRC3 increases pemetrexed resistance by decreasing chemotherapy-induced apoptosis via downregulating ROS level. Mechanistically, SRC3 enhances pemetrexed resistance via regulating Nrf2 and AKT signaling pathway. High SRC3 expression is positively correlated with decreased responsiveness to pemetrexed rather than other chemotherapeutic agents and predicts a poorer clinical outcome in lung adenocarcinoma patients. These data indicate that knockdown of SRC3 may be useful to treat pemetrexed-resistant lung cancer and may also provide a specific biomarker to predict pemetrexed responsiveness in lung cancer.

Advanced Glycation End Products (AGEs) Induce Apoptosis of Fibroblasts by Activation of NLRP3 Inflammasome via Reactive Oxygen Species (ROS) Signaling Pathway

Background

Type 2 diabetes impairs the healing process and induces apoptosis of fibroblasts, which are thought to be involved in this process. We investigated the possible mechanisms involved in AGEs-induced apoptosis of human dermal fibroblasts.

Material/Methods

We examined the expression of apoptosis-related proteins in fibroblasts isolated from human diabetic wounds. Human dermal fibroblasts exposed to AGEs were used to study the links among apoptosis, ROS, and NLRP3 inflammasome activation. Signaling mechanisms were evaluated by preincubating the cells with appropriate inhibitors. Cleaved caspase-8, cleaved caspase-3, BAX, Bcl-2, and NLRP3 inflammasome expression were measured by Western blot analysis. ROS generation, cell viability, and cell apoptosis were assessed.

Results

We observed a higher level of cleaved caspase-8 and cleaved caspase-3 expression in fibroblasts isolated from human diabetic wounds compared with controls. AGEs decreased the proliferation of cells in a concentration-dependent and time-dependent manner. The exposure of fibroblasts to AGEs significantly increased the number of cells in early and late apoptosis stages. AGES-induced human dermal fibroblasts showed high expressions of cleaved caspase3, cleaved caspase8, and Bax. Treatment with AGEs induced the expression of NLRP3, caspase-1, and ASC. AGES-induced apoptosis was blocked by BAY 11–7082, an inhibitor of the NLRP3 inflammasome. AGEs increased the production of ROS in fibroblasts, and its apoptogenic effect was blocked by NAC.

Conclusions

AGEs cause apoptosis of fibroblasts by inducing the generation of ROS and activating the NLRP3 inflammasome. In vivo experiments are needed to confirm these results.

Glycyrrhiza glabra-Enhanced Extract and Adriamycin Antiproliferative Effect on PC-3 Prostate Cancer Cells

Prostate cancer is the second most commonly diagnosed cancer in men worldwide, which is almost incurable, once it progresses into the metastatic stage. Adriamycin (ADR) is a known chemotherapeutic agent that causes severe side effects. In recent years, studies in natural plant products have revealed their anticancer activities. In particular, Glycyrrhiza glabra enhanced extract (GGE), commonly known as licorice, has been reported to exert antiproliferative properties against cancer cells. In this study, the cytotoxic potential of GGE was assessed in PC-3 cells, when it is administrated alone or in combination with Adriamycin. PC-3 cells were treated with GGE and/or ADR, and the inhibition of cell proliferation was evaluated by the MTT assay. Cell cycle alterations and apoptosis rate were measured through flow cytometry. Expression levels of autophagy-related genes were evaluated with specific ELISA kits, Western blotting, and real-time PCR, while NMR spectrometry was used to identify the implication of specific metabolites. Our results demonstrated that GGE alone or in co-treatment with ADR shows antiproliferative properties against PC-3 cells, which are mediated by both apoptosis and autophagy mechanisms.

Autophagy facilitates the release of immunogenic signals following chemotherapy in 3D models of mesothelioma

We have previously shown that nearly half of mesothelioma patients have tumors with low autophagy and that these patients have a significantly worse outcome than those with high autophagy. We hypothesized that autophagy may be beneficial by facilitating immunogenic cell death (ICD) of tumor cells following chemotherapy. An important hallmark of ICD is that death of tumor cells is preceded or accompanied by the release of damage-associated molecular pattern molecules (DAMPs), which then can stimulate an antitumor immune response. Therefore, we measured how autophagy affected the release of three major DAMPs: high mobility group box 1 (HMGB1), ATP, and calreticulin following chemotherapy. We found that autophagy in three-dimensional (3D) models with low autophagy at baseline could be upregulated with the cell-permeant Tat-BECN1 peptide and confirmed that autophagy in 3D models with high autophagy at baseline could be inhibited with MRT 68921 or ATG7 RNAi, as we have previously shown. In in vitro 3D spheroids, we found that, when autophagy was high or upregulated, DAMPs were released following chemotherapy; however, when autophagy was low or inhibited, DAMPs release was significantly impaired. Similarly, in ex vivo tumors, when autophagy was high or upregulated, HMGB1 was released following chemotherapy but, when autophagy was low, HMGB1 release was not seen. We conclude that autophagy can be upregulated in at least some tumors with low autophagy and that upregulation of autophagy can restore the release of DAMPs following chemotherapy. Autophagy may be necessary for ICD in this tumor.

Med19 is involved in chemoresistance by mediating autophagy through HMGB1 in breast cancer

Adriamycin (ADM)-based regimens are the most effective chemotherapeutic treatments for breast cancer. However, intrinsic and acquired chemoresistance is a major therapeutic problem. Our goal was to clarify the role of mediator complex subunit 19 (Med19) in chemotherapy resistance and to elucidate the related molecular mechanisms. In this study, ADM-resistant human cells (MCF-7/ADM) and tissues exhibited increased Med19 expression and autophagy levels relative to the corresponding control groups. Additionally, MCF-7/ADM cells showed changes in two selective markers of autophagy. There was a dose-dependent increase in the light chain 3 (LC3)-II/LC3-I ratio and a decrease in sequestosome 1 (P62/SQSTMl) expression. Furthermore, lentivirus-mediated Med19 inhibition significantly attenuated the LC3-II/LC3-I ratio, autophagy-related gene 3 (Atg3) and autophagy-related gene 5 (Atg5) expression, P62 degradation, and red fluorescent protein-LC3 dot formation after treatment with ADM or rapamycin, an autophagy activator. Furthermore, the antiproliferative effects of ADM, cisplatin (DDP), and taxol (TAX) were significantly enhanced after suppressing Med19 expression. Notably, the effects of Med19 on autophagy were mediated through the high-mobility group box-1 (HMGB1) pathway. Our findings suggest that Med19 suppression increased ADM chemosensitivity by downregulating autophagy through the inhibition of HMGB1 signaling in human breast cancer cells. Thus, the regulatory mechanisms of Med19 in autophagy should be investigated to reduce tumor resistance to chemotherapy.

Autophagy flux inhibition mediated by celastrol sensitized lung cancer cells to TRAIL‑induced apoptosis via regulation of mitochondrial transmembrane potential and reactive oxygen species

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is well known as a transmembrane cytokine and has been proposed as one of the most effective anti-cancer therapeutic agents, owing to its efficiency to selectively induce cell death in a variety of tumor cells. Suppression of autophagy flux has been increasingly acknowledged as an effective and novel therapeutic intervention for cancer. The present study demonstrated that the anti-cancer and anti-inflammatory drug celastrol, through its anti-metastatic properties, may initiate TRAIL-mediated apoptotic cell death in lung cancer cells. This sensitization was negatively affected by N-acetyl-l-cysteine, which restored the mitochondrial membrane potential (ΔΨm) and inhibited reactive oxygen species (ROS) generation. Notably, treatment with celastrol caused an increase in microtubule-associated proteins 1A/1B light chain 3B-II and p62 levels, whereas co-treatment of celastrol and TRAIL increased active caspase 3 and 8 levels compared with the control, confirming inhibited autophagy flux. The combined use of TRAIL with celastrol may serve as a safe and adequate therapeutic technique for the treatment of TRAIL-resistant lung cancer, suggesting that celastrol-mediated autophagy flux inhibition sensitized TRAIL-initiated apoptosis via regulation of ROS and ΔΨm.

2-Bromopalmitate sensitizes osteosarcoma cells to adriamycin-induced apoptosis via the modulation of CHOP

Osteosarcoma is the most common primary malignant bone tumour, but the survival rate of patients has plateaued since the mid-1980s. Adriamycin is an integral component of the current first-line chemotherapies used for osteosarcoma, but dose-dependent severe side effects often limit its clinical application. Here, we propose a potential combination regimen in which adriamycin plus 2-bromopalmitate, a palmitoylation inhibitor, exhibited powerful therapeutic effects on osteosarcoma. First, 2-bromopalmitate strongly increased the proliferation inhibition of adriamycin in both human osteosarcoma cell lines and primary osteosarcoma cells. Adriamycin-induced apoptosis in osteosarcoma cells was enhanced when synergized with 2-bromopalmitate. Our study indicated that the reactive oxygen species scavenger NAC and GSH could largely reverse the apoptosis induced by adriamycin combined with 2-bromopalmitate, demonstrating that reactive oxygen species played an essential role in this combination therapy. Moreover, CHOP was remarkably elevated in the combination group, and silencing of CHOP almost completely blocked the apoptosis induced by the combination of 2-bromopalmitate and adriamycin. Taken together, our study provides a prospective therapeutic strategy to eliminate osteosarcoma, which is propitious to clinical combination therapy development.

A porous polyaniline nanotube sorbent for solid-phase extraction of the fluorescent reaction product of reactive oxygen species in cells, and its determination by HPLC

A method is described for extracting and detecting the fluorescent reaction product (2',7'-dichlorofluorescein, DCF) that is formed by reaction of reactive oxygen species (ROS) with dichlorodihydrofluorescein diacetate (DCFH-DA). DCF is extracted by using porous polyaniline nanotubes (PPN) which have a large specific surface and pore volume which favor the adsorption capacity. Additional attractive features include an appropriate pore size distribution, hydrophobic surface, and electron-attracting groups which contribute to DCF adsorption. A variety of methods was applied to characterize the morphology of PPN. Under optimal conditions and by performing DCF in 0.08-1.0 μM concentrations, the correlation coefficient of the calibration plot is 0.999. The limits of detection for standard DCF solutions is 20 nM. Compared with commercial sorbents for solid-phase extraction (SPE) such as commercially available carbon or Welchrom® C18, the use of the new sorbent results in better retraction recovery (92%) and longer reuse times (30 times). Doxorubicin and X-ray radiation were used to externally stimulate the ROS production in HepG2 and Hela cells. ROS was stabled by DCFH-DA and quantified by DCF. Following SPE, DCF was detected by HPLC and the concentration ROS was calculated. Graphical abstract ᅟ.

Qianlie Xiaozheng Decoction Induces Autophagy in Human Prostate Cancer Cells via Inhibition of the Akt/mTOR Pathway

Qianlie Xiaozheng decoction (QLXZD), a traditional Chinese medicinal formula, has been used clinically to treat advanced prostate cancer (PCa) for more than 10 years. However, experimental evidence supporting its efficacy is lacking. Here, we investigated the anticancer properties and molecular mechanism of QLXZD in vitro in a human PCa cell line (PC3) and in vivo using PC3 xenografts in nude mice. We confirmed the antineoplastic activity of QLXZD by analyzing cell viability and tumor volume growth, which decreased significantly compared to that of the controls. Autophagy following QLXZD treatment was detected morphologically using transmission electron microscopy and was confirmed by measuring the expression of autophagy markers (LC3-II and p62) using fluorescence analysis, flow cytometry, and western blotting. Increasing autophagic flux induced by QLXZD was monitored via pmCherry-GFP-LC3 fluorescence analysis. QLXZD-induced autophagic cell death was alleviated by the autophagy inhibitors, 3-methyl adenine and hydroxychloroquine. We evaluated the total expression and phosphorylation levels of proteins involved in the Akt/mTOR pathway regulating autophagy. Phosphorylation of Akt, mTOR, and p70S6K, but not total protein levels, decreased following treatment. This is the first study to demonstrate the autophagy-related mechanistic pathways utilized during QLXZD-mediated antitumor activity both in vitro and in vivo. These findings support the clinical use of QLXZD for PCa treatment.

H2O2 treatment or serum deprivation induces autophagy and apoptosis in naked mole-rat skin fibroblasts by inhibiting the PI3K/Akt signaling pathway

Naked mole-rats (NMR; Heterocephalus glaber) display extreme longevity and resistance to cancer. Here, we examined whether autophagy contributes to the longevity of NMRs by assessing the effects of the PI3K/Akt pathway inhibitor LY294002 and the autophagy inhibitor chloroquine (CQ) on autophagy and apoptosis in NMR skin fibroblasts. Serum starvation, H2O2 treatment, and LY294002 treatment all increased the LC3-II/LC3-I ratio and numbers of double-membraned autophagosomes and autophagic vacuoles, and decreased levels of p70S6K, p-Akt^Ser473, and p-Akt^Thr308. By contrast, CQ treatment decreased p70S6K, Akt^Ser473, and Akt^Thr308 levels. The Bax/Bcl-2 ratio increased after 12 h of exposure to LY294002 or CQ. These data show that inhibiting the Akt pathway promotes autophagy and apoptosis in NMR skin fibroblasts. Furthermore, LY294002 or CQ treatment decreased caspase-3, p53, and HIF1-α levels, suggesting that serum starvation or H2O2 treatment increase autophagy and apoptosis in NMR skin fibroblasts by inhibiting the PI3K/Akt pathway. CQ-induced inhibition of late autophagy stages also prevented Akt activation and induced apoptosis. Finally, the HIF-1α and p53 pathways were involved in serum starvation- or H2O2-induced autophagy in NMR skin fibroblasts.

Dual inhibition of BDNF/TrkB and autophagy: a promising therapeutic approach for colorectal cancer

Colorectal cancer (CRC) is the most common digestive cancer in the Western world. Despite effective therapies, resistance and/or recurrence frequently occur. The present study investigated the impact of two survival pathways—neurotrophic factors (TrkB/BDNF) and autophagy—on cell fate and tumour evolution. In vitro studies were performed on two CRC cell lines, SW480 (primary tumour) and SW620 (lymph node invasion), which were also used for subcutaneous xenografts on a nude mouse model. In addition, the presence of neurotrophic factors (NTs) and autophagy markers were assessed in tissue samples representative of different stages. On the basis of our previous study (which demonstrated that TrkB overexpression is associated with prosurvival signaling in CRC cells), we pharmacologically inhibited NTs pathways with K252a. As expected, an inactivation of the PI3K/AKT pathway was observed and CRC cells initiated autophagy. Conversely, blocking the autophagic flux with chloroquine or with ATG5‐siRNA overactivated TrkB/BDNF signaling. In vitro, dual inhibition improved the effectiveness of single treatment by significantly reducing metabolic activity and enhancing apoptotic cell death. These findings were accentuated in vivo, in which dual inhibition induced a spectacular reduction in tumour volume following long‐term treatment (21 days for K252a and 12 days for CQ). Finally, significant amounts of phospho‐TrkB and LC3II were found in the patients’ tissues, highlighting their relevance in CRC tumour biology. Taken together, our results show that targeting NTs and autophagy pathways potentially constitutes a new therapeutic approach for CRC.

Redox Imbalance in the Development of Colorectal Cancer

Redox imbalance is resulted from the destruction of balance between oxidants and antioxidants. The dominant oxidants are reactive oxygen species (ROS), which are involved in multiple cellular processes by physiologically transporting signal as a second messenger or pathologically oxidizing DNA, lipids, and proteins. Generally speaking, low concentration of ROS is indispensable for cell survival and proliferation. However, high concentration of ROS is cytotoxic. Additionally, ROS are now known to induce the oxidative modification of macromolecules especially proteins. The redox modification of proteins is involved in numerous biological processes related to diseases including CRC. Herein, we attempt to afford an overview that highlights the crosstalk between redox imbalance and CRC.

Immuno-modulatory and cellular antioxidant activities of κ-selenocarrageenan in combination with Epirubicin in H22 hepatoma-bearing mice

BACKGROUND

Human hepatocellular carcinoma (HCC) has a high rate of tumor recurrence and metastasis, resulting in shortened survival time. The aim of this study is to evaluate the synergistic anti-tumor effects and underlying mechanism of κ-selenocarrageenan (KSC) in combination with the chemotherapy drug epirubicin (EPI) in H22 tumor-bearing mice.

METHODS

Hepatocellular carcinoma H22 cells were implanted into mice. After the transplants were successfully established, the animals were divided into four groups: namely the control group, the KSC group, the EPI group and the KSC+EPI group. The effects of KSC and EPI on tumor growth, survival time, thymus index, spleen index, white blood cells (WBC), splenocyte proliferation, natural killer (NK) cell activity, serum TNF-α and IL-2 levels, and antioxidant enzymes in the liver cells were determined.

RESULTS

KSC and/or EPI significantly reduced tumor weight and prolonged the survival time. Furthermore, KSC could attenuate EPI-induced atrophy in the thymus and spleen, as well as other toxicities, which may indicate an additive effect of this combination against organ dysfunction and cellular injury. KSC significantly promoted Con A- and LPS-stimulated splenocyte proliferation, enhanced NK cell activity, and reversed the inhibition of NK activity induced by EPI (P<0.01). In addition, KSC could elevate serum TNF-α and IL-2 levels, increase the GSH-Px, SOD, CAT and GSH activity levels in liver tissue, and reduce MDA content.

CONCLUSIONS

These results suggest that KSC can regulate immune function in mice and suppress the growth of tumor in H22 tumor-bearing mice, and its synergistic antitumor activity with epirubicin may be related to its antioxidant and immuno-modulatory effects.