Hepatocellular carcinoma-related cyclin D1 is selectively regulated by autophagy degradation system

SQSTM1/p62 predicts prognosis and upregulates the transcription of CCND1 to promote proliferation in mantle cell lymphoma

Mantle cell lymphoma (MCL) is a rare, highly invasive non-Hodgkin's lymphoma. The main pathogenesis of MCL is associated with the formation of the IgH/CCND1 fusion gene and nuclear overexpression of cyclin D1, which accelerates the cell cycle, leading to tumorigenesis. The prognosis with current standard chemotherapy is still unsatisfactory. SQSTM1/p62 is a multifunctional adaptor that plays an important role in various tumors. Here, we found that the expression of p62 in MCL tissues was higher than that in hyperplastic lymphadenitis patients. Patients with low p62 expression in MCL cells had better overall survival and progression-free survival rates than those with high expression (p = 0.024 and p = 0.025, respectively). Multivariate Cox analysis indicated that the calculated death risk (hazard ratio [HR]) in patients with high expression levels of p62 increased to 2.742 (95% confidence interval (CI) of 1.268-5.852, p = 0.01), which was higher than those with low levels. Silencing p62 impaired Jeko-1 and Granta519 cell proliferation while downregulating CCND1 mRNA and protein expression, thereby inducing G0/G1 cell cycle arrest. However, silencing p62 does not affect the fusion of IgH and CCND1. Luciferase reporter gene analysis and chromatin immunoprecipitation analysis demonstrated that p62 may regulate CCND1 gene expression through Nrf2. These results provide evidence that p62 can predict poor prognosis in MCL. The precise targeting of p62 therapy reduces the promoting effect of Nrf2 on CCND1, thereby preventing cell cycle progression and effectively inhibiting tumor proliferation. Therefore, p62 may provide a potential target for MCL.

Loss of SETD2 in wild-type VHL clear cell renal cell carcinoma sensitizes cells to STF-62247 and leads to DNA damage, cell cycle arrest, and cell death characteristic of pyroptosis

Loss of chromosome 3p and loss of heterogeneity of the von Hippel-Lindau (VHL) gene are common characteristics of clear cell renal cell carcinoma (ccRCC). Despite frequent mutations on VHL, a fraction of tumors still grows with the expression of wild-type (WT) VHL and evolve into an aggressive subtype. Additionally, mutations on chromatin-modifying genes, such as the gene coding for the histone methyltransferase SET containing domain 2 (SETD2), are essential to ccRCC evolution. We previously identified STF-62247, a small molecule first discovered as a synthetically lethal molecule for VHL-deficient cells by blocking late stages of autophagy. This study investigated how other commonly mutated genes in ccRCC could impact the response to STF-62247. We showed that SETD2 inactivation in ccRCC cells expressing WT-VHL became vulnerable to STF-62247, as indicated by decreases in cell proliferation and survival. Furthermore, activation of the DNA damage response pathway leads to the loss of M-phase inducer phosphatase 1 (CDC25A) and cell cycle arrest in S phase. Cleavage of both caspase-3 and gasdermin E suggests that STF-62247 eliminates WT-VHL ccRCC cells through pyroptosis specifically when SETD2 is inactivated.

Advancing brain tumor therapy: unveiling the potential of PROTACs for targeted protein degradation

The long-term treatment of malignancies, particularly brain tumors, is challenged by abnormal protein expression and drug resistance. In terms of potency, selectivity, and overcoming drug resistance, Proteolysis Targeting Chimeras (PROTACs), a cutting-edge method used to selectively degrade target proteins, beats traditional inhibitors. This review summarizes recent research on using PROTACs as a therapeutic strategy for brain tumors, focusing on their mechanism, benefits, limitations, and the need for optimization. The review draws from a comprehensive search of peer-reviewed literature, scientific databases, and clinical trial databases. Articles published up to the knowledge cutoff date up to 14 April 2023 were included. Inclusion criteria covered PROTAC-based brain tumor therapies, including preclinical and early clinical studies, with no restrictions on design or publication type. We included studies using in vitro, in vivo brain tumor models, and human subjects. Eligible treatments involved PROTACs targeting proteins linked to brain tumor progression. We evaluated the selected studies for methodology, including design, sample size, and data analysis techniques. A narrative synthesis summarized key outcomes and trends in PROTAC-based brain tumor therapy. Recent research shows PROTACs selectively degrade brain tumor-related proteins with minimal off-target effects. They offer enhanced potency, selectivity, and the ability to combat resistance compared to traditional inhibitors. PROTACs hold promise for brain tumor treatment offering advantages over traditional inhibitors, but more research is needed to refine their mechanisms, efficacy, and safety. Larger-scale trials and translational studies are essential for assessing their clinical utility.

Studying the impact of chitosan salicylaldehyde/schiff base/CuFe2O4 in PC3 cells via theoretical studies and inhibition of PI3K/AKT/mTOR signalling

In this elucidation, the nucleophilic attack of salicyladehyde with chitosan, which was obtained from the shrimp shell, afforded the cellulose aldehyde (Schiff base), and then the dispersion of CuFe2O4 on the surface of cellulose aldehyde gave the novel nanomaterial of bimetallic oxide, which was confirmed through spectral analysis such as FT-IR, NMR, SEM, and XRD analysis. Moreover, the anti-proliferative effect of chitosan, chitosan salicylaldehyde, and chitosan salicylaldehyde/CuFe2O4 was evaluated in PC3 human prostate cancer cells and HSF normal human skin fibroblasts. After 48 h, PC3 cell proliferation was significantly inhibited by chitosan salicylaldehyde/CuFe2O4 and chitosan salicylaldehyde (IC50 = 35.3 and 45.55 µg/ml, respectively) without any effects on normal HSF cells. The mRNA expression levels of PI3K, AKT, mTOR, and CCND1 were examined in PC3-treated cells by using QRT-PCR, and the results demonstrated that, by down-regulating the expression levels of these genes, chitosan salicylaldehyde/CuFe2O4 significantly affected prostate cancer cell proliferation, progression, and autophagy more than chitosan salicylaldehyde. Furthermore, the docking stimulation of the chitosan derivatives with different proteins showed the presence of CuFe2O4 particles effect on the interaction inside their pockets and increased the activities, and it's related to biological evaluation. Additionally, the theoretical investigation of these chitosan derivatives and the determination of their physical descriptors showed the activity of bimetallic oxide and the presence of electrostatic hydrogen bond interaction. Finally, these findings may suggest that chitosan salicylaldehyde/CuFe2O4 has a promising anticancer impact against prostate cancer.

Circ-PAN3 facilitates hepatocellular carcinoma growth via sponging miR-153 and upregulating cyclin D1

Background

Circular RNAs (circRNAs) play a pivotal role in the development and advancement of various cancer types. However, the involvement of circ-PAN3 in hepatocellular carcinoma (HCC) is not well understood. To shed light on this, we conducted a comprehensive study through biochemistry, cell biology, molecular biology, and bioinformatics techniques to investigate the role of circ-PAN3 and its associated pathway in the progression of HCC.

Methods

Cell Counting Kit-8 (CCK-8) assay and colony formation assay were utilized to evaluate cell proliferation; Quantitative real-time PCR (RT-qPCR) and Western blot were adopted for assessing mRNA and protein expression; Annexin V/propidium iodide (PI) staining was applied to detect cellular apoptosis; CircInteractome and Targetscan databases were searched to predict potential targets of circRNA and miRNA; Luciferase reporter assay and RNA pull-down assay were performed to examine the interaction of RNA molecules.

Conclusions

Our findings revealed a significant increase in circ-PAN3 expression in HCC clinical specimens, which correlated with a poor survival rate in HCC patients. Knockdown of circ-PAN3 resulted in impaired cell proliferation, reduced cell survival, and inhibited tumorigenesis of HCC in vivo. Further analysis demonstrated that circ-PAN3 could serve as a sponge for miR-153, leading to a decrease in its expression level. This in turn upregulated cyclin D1 and ultimately promoted the proliferation of HCC cells. Additionally, overexpression of cyclin D1 mitigated the inhibitory effect on HCC proliferation induced by circ-PAN3 knockdown. Our study highlights the presence of a novel circ-PAN3/miR-153/cyclin D1 regulatory axis that plays a crucial role in the progression of HCC.

Autophagic degradation of CDK4 is responsible for G0/G1 cell cycle arrest in NVP-BEZ235-treated neuroblastoma

BACKGROUND

CDK4 is highly expressed and associated with poor prognosis and decreased survival in advanced neuroblastoma (NB). Targeting CDK4 degradation presents a potentially promising therapeutic strategy compared to conventional CDK4 inhibitors. However, the autophagic degradation of the CDK4 protein and its anti-proliferation effect in NB cells has not been mentioned.

RESULTS

We identified autophagy as a new pathway for the degradation of CDK4. Firstly, autophagic degradation of CDK4 is critical for NVP-BEZ235-induced G0/G1 arrest, as demonstrated by the overexpression of CDK4, autophagy inhibition, and blockade of autophagy-related genes. Secondly, we present the first evidence that p62 binds to CDK4 and then enters the autophagy-lysosome to degrade CDK4 in a CTSB-dependent manner in NVP-BEZ235 treated NB cells. Similar results regarding the interaction between p62 and CDK4 were observed in the NVP-BEZ235 treated NB xenograft mouse model.

CONCLUSIONS

Autophagic degradation of CDK4 plays a pivotal role in G0/G1 cell cycle arrest in NB cells treated with NVP-BEZ235.

Diosmin reduces the stability of Snail and Cyclin D1 by targeting FAK to inhibit NSCLC progression

BACKGROUND

In different tumours, focal adhesion kinase (FAK), a nonreceptor tyrosine kinase, is upregulated and hence, it represents a promising target for cancer therapy. However, the development of FAK kinase inhibitors has faced a number of challenges. It is therefore imperative that new, effective FAK kinase inhibitors be identified promptly.

METHODS

Small molecules that target FAK were identified through molecular docking and validated through surface plasmon resonance (SPR) and cell thermal shift analysis. We investigated the pharmacological effects of FAK kinase inhibitors using CCK-8, colony formation, EdU, and Transwell assays and cell cycle analysis. The molecular mechanism was determined via methods such as coimmunoprecipitation, RNA pull-down and RNA immunoprecipitation.

RESULTS

Here, we confirmed that diosmin (Dio) is an inhibitor of FAK and demonstrated its anti-proliferative and anti-metastatic effects in lung adenocarcinoma. Mechanistically, Dio inhibited tumour proliferation and metastasis by impeding the catalytic activity of FAK. Dio activated the ubiquitin proteasome pathway to induce Cyclin D1 degradation, while inhibiting tumour proliferation and reversing the epithelial mesenchymal transition (EMT) process by reducing the mRNA stability of Snail, thereby inhibiting cancer metastasis. In addition, the inhibitory effect of Dio on lung adenocarcinoma was validated in a mouse xenograft model.

CONCLUSION

These results support the tumour-promoting role of FAK in lung adenocarcinoma by stabilizing Cyclin D1 and Snail and suggest that Dio is a promising candidate for FAK inhibition.

Identification of pyroptosis subtypes and prognosis model of hepatocellular carcinoma based on pyroptosis-related genes

BACKGROUND

Hepatocellular carcinoma (HCC) is a common malignant tumor with poor prognosis. Pyroptosis, a type of programmed cell death, regulates tumor cell development. However, the role of pyroptosis-related genes (PRGs) in HCC and their association with prognosis are unclear.

METHODS

We conducted bioinformatics analysis to identify PRGs in The Cancer Genome Atlas-Liver Hepatocellular Carcinoma (TCGA-LIHC) patients. Consensus clustering classified patients into different subtypes. We used LASSO regression to established a pyroptosis subtype-related score (PSRS) related to prognosis. OncoPredict identified potential pharmaceuticals based on PSRS.

RESULTS

We found 20 HCC-related PRGs in 335 TCGA-LIHC patients. Consensus clustering classified patients into two subtypes. Subtype I had better overall survival and higher response to anti-PD1 treatment. The prognostic model involving 20 genes predicted poorer prognosis for high-PSRS group. The model was validated in two external cohorts. OncoPredict identified 65 potential pharmaceuticals based on PSRS.

CONCLUSION

Our investigation revealed a correlation between pyroptosis and HCC. We established PSRS as independent risk factors for predicting prognosis. The study paves the way for using PRGs as prognostic biomarkers and exploring personalized therapy for HCC.

Sphingosine kinase 2 and p62 regulation are determinants of sexual dimorphism in hepatocellular carcinoma

OBJECTIVE

Hepatocellular carcinoma (HCC) is the third leading cause of cancer mortality, and its incidence is increasing due to endemic obesity. HCC is sexually dimorphic in both humans and rodents with higher incidence in males, although the mechanisms contributing to these correlations remain unclear. Here, we examined the role of sphingosine kinase 2 (SphK2), the enzyme that regulates the balance of bioactive sphingolipid metabolites, sphingosine-1-phosphate (S1P) and ceramide, in gender specific MASH-driven HCC.

METHODS

Male and female mice were fed a high fat diet with sugar water, a clinically relevant model that recapitulates MASH-driven HCC in humans followed by physiological, biochemical cellular and molecular analyses. In addition, correlations with increased risk of HCC recurrence were determined in patients.

RESULTS

Here, we report that deletion of SphK2 protects both male and female mice from Western diet-induced weight gain and metabolic dysfunction without affecting hepatic lipid accumulation or fibrosis. However, SphK2 deficiency decreases chronic diet-induced hepatocyte proliferation in males but increases it in females. Remarkably, SphK2 deficiency reverses the sexual dimorphism of HCC, as SphK2-/- male mice are protected whereas the females develop liver cancer. Only in male mice, chronic western diet induced accumulation of the autophagy receptor p62 and its downstream mediators, the antioxidant response target NQO1, and the oncogene c-Myc. SphK2 deletion repressed these known drivers of HCC development. Moreover, high p62 expression correlates with poor survival in male HCC patients but not in females. In hepatocytes, lipotoxicity-induced p62 accumulation is regulated by sex hormones and prevented by SphK2 deletion. Importantly, high SphK2 expression in male but not female HCC patients is associated with a more aggressive HCC differentiation status and increased risk of cancer recurrence.

CONCLUSIONS

This work identifies SphK2 as a potential regulator of HCC sexual dimorphism and suggests SphK2 inhibitors now in clinical trials could have opposing, gender-specific effects in patients.

A transcriptome-wide association study identified susceptibility genes for hepatocellular carcinoma in East Asia

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide and is prevalent in East Asia. Although genome-wide association studies (GWASs) of HCC have identified 23 risk regions, the susceptibility genes underlying these associations largely remain unclear. To identify novel candidate genes for HCC, we conducted liver single-tissue and cross-tissue transcriptome-wide association studies (TWASs) in two populations of East Asia.

METHODS

GWAS summary statistics of 2,514 subjects (1,161 HCC cases and 1,353 controls) from the Chinese Qidong cohort and 161,323 subjects (2,122 HCC cases and 159,201 controls) from the BioBank Japan project were used to conduct TWAS analysis. The single-tissue and cross-tissue TWAS approaches were both used to detect the association between susceptible genes and the risk of HCC. TWAS identified genes were further annotated by Metascape, UALCAN, GEPIA2, and DepMap.

RESULTS

We identified 22 novel genes at 16 independent loci significantly associated with HCC risk after Bonferroni correction. Of these, 13 genes were located in novel regions. Besides, we found 83 genes overlapped in the Chinese and Japanese cohorts with P < 0.05, of which, three genes (NUAK2, HLA-DQA1, and ATP6V1G2) were discerned by both single-tissue and cross-tissue TWAS approaches. Among the genes identified through TWAS, a significant proportion of them exhibit a credible role in HCC biology, such as FAM96B, HSPA5, POLRMT, MPHOSPH10, and RABL2A. HLA-DQA1, NUAK2, and HSPA5 associated with the process of carcinogenesis in HCC as previously reported.

CONCLUSIONS

Our findings highlight the value of leveraging the gene expression data to identify new candidate genes beyond the GWAS associations and could further provide a genetic insight for the biology of HCC.

Assessment of the therapeutic potential of a novel phosphoramidate acyclic nucleoside on induced hepatocellular carcinoma in rat model

AIMS

Hepatocellular Carcinoma (HCC) is renowned as a deadly primary cancer of hepatic origin. Sorafenib is the drug-of-choice for targeted treatment of unresectable end-stage HCC. Unfortunately, great proportion of HCC patients showed intolerance or unresponsiveness to treatment. This study assesses potency of novel ProTide; SH-PAN-19 against N-Nitrosodiethylamine (DEN)-induced HCC in male Wistar rats, compared to Sorafenib.

MAIN METHODS

Structural entity of the synthesized compound was substantiated via FT-IR, UV-Vis, 1H NMR and 13C NMR spectroscopic analysis. In vitro, SH-PAN-19 cytotoxicity was tested against 3 human cell lines; hepatocellular carcinoma; HepG-2, colorectal carcinoma; HCT-116 and normal fibroblasts; MRC-5. In vivo, therapeutic efficacy of SH-PAN-19 (300 mg/kg b.w./day) against HCC could be revealed and compared to that of Sorafenib (15 mg/kg b.w./day) by evaluating the morphometric, biochemical, histopathological, immunohistochemical and molecular key markers.

KEY FINDINGS

SH-PAN-19 was relatively safe toward MRC-5 cells (IC50 = 307.6 μg/mL), highly cytotoxic to HepG-2 cells (IC50 = 24.9 μg/mL) and prominently hepato-selective (TSI = 12.35). Oral LD50 of SH-PAN-19 was >3000 mg/kg b.w. DEN-injected rats suffered hepatomegaly, oxidative stress, elevated liver enzymes, hypoalbuminemia, bilirubinemia and skyrocketed AFP plasma titre. SH-PAN-19 alleviated the DEN-induced alterations in apoptotic, angiogenic and inflammatory markers. SH-PAN-19 produced a 2.5-folds increase in Caspase-9 and downregulated VEGFR-2, IL-6, TNF-α, TGFβ-1, MMP-9 and CcnD-1 to levels comparable to that elicited by Sorafenib. SH-PAN-19 resulted in near-complete pathological response versus partial response achieved by Sorafenib.

SIGNIFICANCE

This research illustrated that SH-PAN-19 is a promising chemotherapeutic agent capable of restoring cellular plasticity and could stop HCC progression.

The expression of VEGF and cyclin D1/EGFR in common primary liver carcinomas in Egypt: an immunohistochemical study

Background

The most common types of primary malignant liver tumours are hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA). Treatment options for patients who are inoperable/advanced, or recurring are challenging. Cyclin D1, epidermal growth factor (EGFR) and vascular endothelial growth factor (VEGR) are common carcinogenic proteins that have potential therapeutic targets in various cancers. They have been implicated in the development of HCC and CCA. In this study, we aimed to evaluate the oncogenic function expression of cyclin D1, EGFR and VEGF in HCC and CCA of Egyptian patients. This could help to validate their therapeutic potential.

Material and methods

Tumour cases were selected from 82 cases of primary liver carcinomas, with 58 cases being from HCC and 24 cases from CCA compared to 51 non-tumour adjacent liver cases and 18 from normal liver tissue. The immunohistochemical study of cyclin D1, EGFR and VEGR was conducted.

Results

Cyclin D1, EGFR and VEGF are overexpressed in HCC and CCA as compared to the control group (p < 0.001). Cyclin D1 was related to well-differentiated grade and early pathologic stage in HCC (p = 0.016 and p = 0.042, respectively). The well-differentiated grade showed significantly higher VEGF levels (p = 0.04). In the CCA group, however, EGFR was strongly related to high tumour size (p = 0.047). EGFR and VEGF were overexpressed in HCC raised in the non-cirrhotic liver compared to those developed in post-hepatitic liver cirrhosis (p = 0.003 and p = 0.014).

Conclusion

Cyclin D1, EGFR and VEGF shared significant overexpression in HCC and CCA. EGFR and VEGF may play an oncogenic function in the development of HCC in non-cirrhotic liver. Furthermore, cyclin D1 and VEGF may play a good prognostic function in HCC, but EGFR may play a bad prognostic role in CCA.

In silico approaches for the identification of novel ULK1 inhibitors: pharmacophore model, molecular docking and molecular dynamics simulations

The serine/threonine kinase unc-51-like autophagy activating kinase 1 (ULK1) has been regarded as an attractive target for tumor therapy. In this study, in silico approaches, such as the pharmacophore-based virtual screening strategy, molecular docking and molecular dynamics (MD) simulations, were applied to develop novel potential ULK1 inhibitors. The pharmacophore models based on known aminopyrimidine ULK1 inhibitors were constructed to screen the dataset of 1.68 million compounds, which were obtained via screening the 2.30 million compounds in ChEMBL database by Lipinski's rule of five. Seven novel compounds and 1 known ULK1 inhibitor stand out for the strong virtual biological activity by molecular docking, cluster analysis, Molecular Mechanics/Generalized Born Surface Area (MM/GBSA) calculation and Absorption Distribution Metabolism Excretion Toxicity (ADMET) prediction. Their results of MD included principal component analysis (PCA) and Free Energy Landscapes surface (FELs) indicated that the protein-ligand complex was stable in simulated trajectories of 100 ns. The binding free energy (BFE) calculations showed that a total of 6 novel compounds (CL130, CL834, CL961, CL966, CL163 and CL329) with the stable binding state and stronger BFE (-61.17 to -37.01 kcal/mol) than that of original ligand 3RF (-36.66 kcal/mol). With reference to the ULK1 inhibition of 3RF (IC50 = 160 nM), it can be inferred that these compounds could be used as a new type of potential ULK1 inhibitors and be worthy of further investigation for tumor treatments.Communicated by Ramaswamy H. Sarma.

The role of pyroptosis in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the main histologic type of liver cancer. It accounts for the majority of all diagnoses and deaths due to liver cancer. The induction of tumor cell death is an effective strategy to control tumor development. Pyroptosis is an inflammatory programmed cell death caused by microbial infection, accompanied by activation of inflammasomes and release of pro-inflammatory cytokines, interleukin-1β (IL-1β), and interleukin-18 (IL-18). The cleavage of gasdermins (GSDMs) promotes the occurrence of pyroptosis leading to cell swelling, lysis, and death. Accumulating evidence has indicated that pyroptosis influences the progression of HCC by regulating immune-mediated tumor cell death. Currently, some researchers hold the view that inhibition of pyroptosis-related components may prevent the incidence of HCC, but more researchers have the view that activation of pyroptosis exerts a tumor-inhibitory effect. Growing evidence indicates that pyroptosis can prevent or promote tumor development depending on the type of tumor. In this review, pyroptosis pathways and pyroptosis-related components were discussed. Next, the role of pyroptosis and its components in HCC was described. Finally, the therapeutic significance of pyroptosis in HCC was discussed.

Increased expression of autophagy-related gene 5 indicates poor prognosis in patients with hepatocellular carcinoma

OBJECTIVES

As a critical component of the autophagic machinery, autophagy-related gene 5 (ATG5) is essential for autophagosome formation. Autophagy participates in the transformation and progression of various malignant tumors, but the role of ATG5 in hepatocellular carcinoma (HCC) remains to be illustrated. In this study we aimed to investigate the prognostic significance of ATG5 in HCC.

METHODS

ATG5 expression was evaluated in 89 pairs of HCC tissues and adjacent non-tumor tissues. The relationship between ATG5 expression and patients' clinicopathological characteristics and prognosis were evaluated. Moreover, subgroup analyses were performed regarding patients' age and number of tumors. Nomograms estimating overall survival (OS) and disease-free survival (DFS) were conducted.

RESULTS

ATG5 expression was increased in HCC specimens rather than adjacent non-tumor tissues. The upregulated ATG5 expression was positively associated with serum α-fetoprotein (AFP) level. Moreover, cases with a strong ATG5 expression had a poorer disease-free survival (DFS) and overall survival (OS) than those with a weak ATG5 expression. Multivariate analysis showed that a strong expression of ATG5 was related to a poor OS and DFS in patients with HCC. Further analysis indicated that cases with a higher ATG5 expression had a poorer OS and DFS in the young patients (≤55 years) and those with solitary tumor. The nomogram suggested that there was a coherence between nomogram prediction and the actual situation of patient survival related to ATG5.

CONCLUSION

ATG5 promotes tumor progression in HCC, making it a potential biomarker in the diagnosis and a therapeutic target of HCC.

Secretory autophagy promotes RAB37-mediated insulin secretion under glucose stimulation both in vitro and in vivo

High blood glucose is one of the risk factors for metabolic disease and INS (insulin) is the key regulatory hormone for glucose homeostasis. Hypoinsulinemia accompanied with hyperglycemia was diagnosed in mice with pancreatic β-cells exhibiting autophagy deficiency; however, the underlying mechanism remains elusive. The role of secretory autophagy in the regulation of metabolic syndrome is gaining more attention. Our data demonstrated that increased macroautophagic/autophagic activity leads to induction of insulin secretion in β-cells both in vivo and in vitro under high-glucose conditions. Moreover, proteomic analysis of purified autophagosomes from β-cells identified a group of vesicular transport proteins participating in insulin secretion, implying that secretory autophagy regulates insulin exocytosis. RAB37, a small GTPase, regulates vesicle biogenesis, trafficking, and cargo release. We demonstrated that the active form of RAB37 increased MAP1LC3/LC3 lipidation (LC3-II) and is essential for the promotion of insulin secretion by autophagy, but these phenomena were not observed in rab37 knockout (rab37^-/-) cells and mice. Unbalanced insulin and glucose concentration in the blood was improved by manipulating autophagic activity using a novel autophagy inducer niclosamide (an antihelminthic drug) in a high-fat diet (HFD)-obesity mouse model. In summary, we reveal that secretory autophagy promotes RAB37-mediated insulin secretion to maintain the homeostasis of insulin and glucose both in vitro and in vivo.

Formosanin C suppresses cancer cell proliferation and migration by impeding autophagy machinery

Formosanin C (FC) is a natural compound extracted from Paris formosana Hayata with anticancer activity. FC induces both autophagy and apoptosis in human lung cancer cells. FC-induced depolarization of mitochondrial membrane potential (MMP) may trigger mitophagy. In this study, we clarified the effect of FC on autophagy, mitophagy, and the role of autophagy in FC-related cell death and motility. We found FC caused the continuous increase of LC3 II (representing autophagosomes) from 24 to 72 h without degradation after treatment of lung and colon cancer cells, indicating that FC blocks autophagic progression. In addition, we confirmed that FC also induces early stage autophagic activity. Altogether, FC is not only an inducer but also a blocker of autophagy progression. Moreover, FC increased MMP accompanied by overexpression of COX IV (mitochondria marker) and phosphorylated Parkin (p-Parkin, mitophagy marker) in lung cancer cells, but no colocalization of LC3 with COX IV or p-Parkin was detected under confocal microscopy. Moreover, FC could not block CCCP (mitophagy inducer)-induced mitophagy. These results imply that FC disrupts mitochondria dynamics in the treated cells, and the underlying mechanism deserves further exploration. Functional analysis reveals that FC suppresses cell proliferation and motility through apoptosis and EMT-related pathway, respectively. In conclusion, FC acts as an inducer as well as a blocker of autophagy that results in cancer cell apoptosis and decreased motility. Our findings shed the light on the development of combined therapy with FC and clinical anticancer drugs for cancer treatment.

Secretory autophagy promotes Rab37-mediated exocytosis of tissue inhibitor of metalloproteinase 1

BACKGROUND

Rab37-mediated exocytosis of tissue inhibitor of metalloproteinase 1 (TIMP1), an inflammatory cytokine, under serum-depleted conditions which leads to suppression of lung cancer cell metastasis has been reported. Starvation is also a stimulus of autophagic activity. Herein, we reveal that starvation activates Rab37 and induces autophagy.

METHODS

We used an overexpression/knockdown system to determine the relationship between autophagy and Rab37 in vitro and in vivo. The autophagy activity was detected by immunoblotting, transmission electron microscope, autophagosome purification, and immunofluorescence under the confocal microscope. Lung-to-lung metastasis mouse model was used to clarify the role of autophagy and Rab37 in lung cancer. Clinical lung cancer patient specimens and an online big database were analyzed.

RESULTS

Initially, we demonstrated that active-form Rab37 increased LC3-II protein level (the marker of autophagosome) and TIMP1 secretion. Accordingly, silencing of Rab37 gene expression alleviated Rab37 and LC3-II levels as well as TIMP1 secretion, and induction of autophagy could not increase TIMP1 exocytosis under such conditions. Moreover, silencing the Atg5 or Atg7 gene of lung cancer cells harboring active-mutant Rab37 (Q89L) led to decreased autophagy activity and TIMP1 secretion. In the lung-to-lung metastasis mouse model, increased TIMP1 expression accompanied by amiodarone-induced autophagy led to decreased tumor nodules and cancer cell metastasis. These phenomena were reversed by silencing the Atg5 or Atg7 gene. Notably, increasing autophagy activity alone showed no effect on TIMP1 secretion under either Rab37 or Sec22b silencing conditions. We further detected colocalization of LC3 with either Rab37 or TIMP1, identified Rab37 and Sec22b proteins in the purified autophagosomes of the lung cancer cells harboring the active-form Rab37 gene, and confirmed that these proteins are involved in the secretion of TIMP1. We reveal that autophagic activity was significantly lower in the tumors compared to the non-tumor parts and was associated with the overall lung cancer patient survival rate.

CONCLUSIONS

We are the first to report that autophagy plays a promoting role in TIMP1 secretion and metastasis in a Rab37-dependent manner in lung cancer cells and the lung-to-lung mouse model.

ULK1 inhibition attenuates telomerase activity in hepatic cells

Autophagy and telomere maintenance are two cellular survival processes that show a strong correlation during human ageing and cancer growth, however, their causal relationship remains unclear. In this study, using an unbiased transcriptomics approach, we uncover a novel role of autophagy genes in regulating telomere extension and maintenance pathways. Concomitantly, the pharmacological inhibition of ULK1 (Unc-51 like autophagy activating kinase 1) attenuated human telomerase reverse transcriptase (hTERT) gene expression and telomerase activity in HepG2 cells. Furthermore, the suppression of telomerase activity upon ULK1 inhibition was associated with telomere shortening and onset of cellular senescence in HepG2 cells. These results, thus, demonstrate a direct role of autophagy in maintaining cellular longevity via regulation of telomerase activity, which may have implications in the pathophysiology of ageing and cancers.

Recreational Drugs and the Risk of Hepatocellular Carcinoma

Recreational or aesthetic drug use is a distinctive behavior of humans, principally attested in the last century. It is known that recreational and illegal drugs are major contributors to the universal morbidity rate worldwide. Many of these substances have a well-established hepatotoxic potential, causing acute or chronic liver injury, liver fibrosis and cirrhosis, but their implications for hepatocellular carcinoma or other varieties of liver tumors are little known. In this article, we perform an extensive literature review, aiming to provide updated information about recreational drug use and the risk of developing liver tumors. Khat use and pyrrolizidine alkaloid consumption (present in some natural plants) have been linked to liver cirrhosis. Kava intake is associated with different liver tumors in animal models but not in humans. Cannabis' potential to accelerate liver fibrosis in chronic hepatitis is controversial according to the existing data. Cigarette smoking is an important contributor to hepatocellular carcinoma, and anabolic androgen steroids are well-defined causes of a variety of liver cancers and other hepatic tumors. Long-term follow-up studies of subjects who have developed injuries in association with the use of recreational drugs are warranted so as to better define the risk of developing hepatocellular carcinoma in association with these substances and, thus, to implement health care policies to combat this preventable cause of cancer.

Autophagy in health and disease: From molecular mechanisms to therapeutic target

Macroautophagy/autophagy is an evolutionally conserved catabolic process in which cytosolic contents, such as aggregated proteins, dysfunctional organelle, or invading pathogens, are sequestered by the double-membrane structure termed autophagosome and delivered to lysosome for degradation. Over the past two decades, autophagy has been extensively studied, from the molecular mechanisms, biological functions, implications in various human diseases, to development of autophagy-related therapeutics. This review will focus on the latest development of autophagy research, covering molecular mechanisms in control of autophagosome biogenesis and autophagosome-lysosome fusion, and the upstream regulatory pathways including the AMPK and MTORC1 pathways. We will also provide a systematic discussion on the implication of autophagy in various human diseases, including cancer, neurodegenerative disorders (Alzheimer disease, Parkinson disease, Huntington's disease, and Amyotrophic lateral sclerosis), metabolic diseases (obesity and diabetes), viral infection especially SARS-Cov-2 and COVID-19, cardiovascular diseases (cardiac ischemia/reperfusion and cardiomyopathy), and aging. Finally, we will also summarize the development of pharmacological agents that have therapeutic potential for clinical applications via targeting the autophagy pathway. It is believed that decades of hard work on autophagy research is eventually to bring real and tangible benefits for improvement of human health and control of human diseases.

Degradation strategy of cyclin D1 in cancer cells and the potential clinical application

Cyclin D1 has been reported to be upregulated in several solid and hematologic tumors, promoting cancer progression. Thus, decreasing cyclin D1 by degradation could be a promising target strategy for cancer therapy. This mini review summarizes the roles of cyclin D1 in tumorigenesis and progression and its degradation strategies. Besides, we proposed an exploration of the degradation of cyclin D1 by FBX4, an F box protein belonging to the E3 ligase SKP-CUL-F-box (SCF) complex, which mediates substrate ubiquitination, as well as a postulate about the concrete combination mode of FBX4 and cyclin D1. Furthermore, we proposed a possible photodynamic therapy strategythat is based on the above concrete combination mode for treating superficial cancer.

HIF-2α-targeted interventional chemoembolization multifunctional microspheres for effective elimination of hepatocellular carcinoma

Transcatheter arterial chemoembolization (TACE) is widely used for the treatment of advanced hepatocellular carcinoma (HCC). However, the long-term hypoxic microenvironment caused by TACE seriously affects the therapeutic effect of TACE. HIF-2α plays a crucial role on the chronic hypoxia process, which might be an ideal target for TACE therapy. Herein, a multifunctional polyvinyl alcohol (PVA)/hyaluronic acid (HA)-based microsphere (PT/DOX-MS) co-loaded with doxorubicin (DOX) and PT-2385, an effective HIF-2α inhibitor, was developed for enhanced TACE treatment efficacy. In vitro and in vivo studies revealed that PT/DOX-MS had a superior ability to treat HCC by blocking the tumor cells in G2/M phase, prompting cell apoptosis, and inhibiting tumor angiogenesis. The antitumor mechanisms of PT/DOX-MS were possibly due to that the introduction of PT-2385 could effectively inhibit the expression level of HIF-2α in hypoxic HCC cells, thereby down-regulating the expression levels of Cyclin D1, VEGF and TGF-α. In addition, the combination of DOX and PT-2385 could jointly inhibit VEGF expression, which was another reason accounting for the combined anti-cancer effect of PT/DOX-MS. Overall, our study demonstrated that PT/DOX-MS is a promising embolic agent for enhanced HCC treatment via the combined effect of hypoxia microenvironment improvement, chemotherapy, and embolization.

LPM3770277, a Potent Novel CDK4/6 Degrader, Exerts Antitumor Effect Against Triple-Negative Breast Cancer

Triple negative breast cancer (TNBC) is a subtype of breast cancer with significant malignancy and poor prognosis but effective treatments are limited. Given the critical role of CDK4/6 in cell cycle and the apparent success of CDK4/6 inhibitors against certain cancer, this study attempted to utilize hydrophobic tagging technology to develop a CDK4/6 degrader against TNBC. We based on the chemical structure of the major metabolite of a clinically approved CDK4/6 inhibitor, abemaciclib, to synthesize three compounds and evaluated their in vitro cytotoxicity. LPM3770277 stood out as the most promising compound which was further confirmed by a series of binding and CDK4/6 degradation studies. LPM3770277 was able to bind to CDK4/6, and time-dependently and dose-dependently increased CDK4/6 protein degradation. Mechanistic study revealed that LPM3770277 exerted its CDK4/6 degradation effect via two machineries: proteasome and lysosome-promoted autophagy. Using in vivo TNBC xenograft cancer model, we found that LPM3770277 demonstrated superior anti-tumor efficacy and safety as compared to abemaciclib, although both compounds exerted similar effects on cell cycle arrest. In conclusion, this study for the first time developed and characterized a CDK4/6 degrader against TNBC using hydrophobic tags, which strongly suggests the viability of hydrophobic tags as a strategy to develop potential treatments against TNBC.

Structure-Based Virtual Screening towards the Discovery of Novel ULK1 Inhibitors with Anti-HCC Activities

There is an urgent need to develop new effective therapies for HCC. Our previous study identified ULK1 as the potential target for HCC therapy and screened the compound XST-14 as a specific inhibitor of ULK1 to suppress HCC progression. However, the poor manufacturability of XST-14 impeded the process of its clinical translation. In this study, we first generated pharmacophore models of ULK1 based on the X-ray structure of UKL1 in complex with ligands. We then screened the Specs chemical library for potential UKL1 inhibitors. By molecular docking, we screened out the 19 compounds through structure-based virtual screening. Through CCK8 activity screening on HCC cells, we found that ZZY-19 displayed obvious cell killing effects on HCC cells. SPR assay indicated that ZZY-19 had a higher binding affinity for ULK1 than XST-14. Moreover, ZZY-19 induced the effects of anti-proliferation, anti-invasion and anti-migration in HCC cells. Mechanistically, ZZY-19 induces autophagy inhibition by reducing the expression of ULK1 on HCC cells. Especially, the combination of ZZY-19 with sorafenib synergistically suppresses the progression of HCC in vivo. Taken together, ZZY-19 was a potential candidate compound that targeted ULK1 and possessed promising anti-HCC activities by inhibiting autophagy.

Pre-mRNA processing factor 19 functions in DNA damage repair and radioresistance by modulating cyclin D1 in hepatocellular carcinoma

Pre-mRNA processing factor 19 (PRP19) is elevated in hepatocellular carcinoma (HCC); however, little is known about its function in DNA damage repair in HCC. In this study, analysis of The Cancer Genome Atlas data and our tumor models after ionizing radiation (IR) treatment indicated that increased expression of PRP19 was positively correlated with DNA damage repair. Gain of PRP19 expression induced by plasmids resulted in decreases in apoptosis and double-strand breaks (DSBs), and an increase in cell survival after IR. Loss of PRP19 expression induced by small interfering RNAs resulted in the accumulation of apoptosis and DSBs, and a decrease in cell survival. Mechanistically, the effect of PRP19 on DNA damage repair was mediated by the modulation of cyclin D1 expression in HCC. PRP19 controlled the translation of cyclin D1 by modulating eukaryotic initiation factor 4E. PRP19 affected the DNA damage repair ability of cyclin D1 by interacting with the WD40 domain. The combination of PRP19 and cyclin D1 was more valuable than each single marker for predicting the prognosis of patients. Taken together, the present results demonstrate that PRP19 promotes DNA damage repair by modulating cyclin D1 expression and function, thereby contributing to the radioresistance in HCC.

CRHBP is degraded via autophagy and exerts anti-hepatocellular carcinoma effects by reducing cyclin B2 expression and dissociating cyclin B2-CDK1 complex

Autophagy is the predominant self-eating catabolic pathway activated in response to nutrient starvation and hypoxia within the microenvironment of varied malignancies, including hepatocellular carcinoma (HCC). SQSTM1/p62 links its cargos to autophagosomes for degradation, and reportedly acts as a contributor for hepatocarcinogenesis. Five GEO gene microarrays identified corticotropin releasing hormone (CRH) binding protein (CRHBP) as a significantly downregulated gene in HCC (log2 Fold change < -3 and p < 0.001), and an earlier human interactome study indicated that CRHBP may interact with p62. This study aimed to explore (1) the role of CRHBP in HCC development, and (2) whether p62-mediated autophagy was responsible for low CRHBP expression within HCC tissue. Following functional experiments first revealed an anti-proliferative, anti-metastatic, and anti-angiogenic role of CRHBP in HCC cells (Huh-7, Li-7 and HCCLM3) and xenografts. CRHBP negatively regulated cyclin B2 expression, and dissociated cyclin B2-CDK1 complex in HCC cells, thereby leading to cell cycle arrest at G2 phase. To simulate HCC microenvironment in vitro, Huh-7 cells were incubated in Earle's Balanced Salt Solution (nutrient starvation) or exposed to 1% O₂ (hypoxic exposure). In addition to activating autophagy, nutrient starvation and hypoxic exposure also induced CRHBP degradation. Interestingly, CRHBP was demonstrated as a novel cargo targeted by p62 for degradation in autophagosomes. Blocking autophagy with 3-MA, chloroquine or siSQSTM1 prevented CRHBP degradation in HCC cells. Collectively, our study uncovers a role for CRHBP in retarding HCC development, reducing cyclin B2 expression and impairing cyclin B2-CDK1 interaction. CRHBP downregulation in HCC may attribute to p62-mediated autophagy.

Mitochondrial dysfunction is involved in the cellular activity inhibition by eleutheroside B in SMMC-7721 and HeLa cells

Eleutheroside B, also known as syringin, has been shown to have various pharmacological activities such as anti-inflammatory, anti-irradiation and antidepressant, but there are few studies on its anti-cancer activity. Its anti-tumor effect on SMMC-7721 cells has not been revealed. Moreover, whether it induces autophagy is still unclear. Thus, the present study investigated whether Eleutheroside B induces apoptosis, autophagy and cellular motility in SMMC-7721 cells and HeLa cells, and explored the underlying molecular mechanisms. SMMC-7721 cells and HeLa cells treated with Eleutheroside B and cell viability measured by MTT assay and trypan blue dye exclusion assay. Apoptosis checked by flow cytometry combined, fluorescent staining. Apoptotic signal proteins and autophagy proteins were checked by Western blot. This study showed that Eleutheroside B inhibited the cell proliferation and blocked cell cycle, migration and invasion as well. Moreover, Eleutheroside B induced apoptosis in SMMC-7721 cells and HeLa cells. It upregulated Bax expression, while simultaneously decreasing Bcl-2 expression. Further elucidation of the mechanism revealed that Eleutheroside B induced mitochondrial dysfunction, with mitochondrial membrane potential collapse and cytochrome c release, suggesting that Eleutheroside B induced apoptosis by triggering mitochondrial pathway. Most importantly, Eleutheroside B could induce autophagy in SMMC-7721 cells and HeLa cells. Taken together, these results suggested Eleutheroside B is a potential therapeutic candidate for HCC and Human cervical cancer.

The Intricate Interplay between Cell Cycle Regulators and Autophagy in Cancer

Simple Summary

Autophagy is an intracellular catabolic program regulated by multiple external and internal cues. A large amount of evidence unraveled that cell-cycle regulators are crucial in its control. This review highlights the interplay between cell-cycle regulators, including cyclin-dependent kinase inhibitors, cyclin-dependent kinases, and E2F factors, in the control of autophagy all along the cell cycle. Beyond the intimate link between cell cycle and autophagy, this review opens therapeutic perspectives in modulating together these two aspects to block cancer progression.

Abstract

In the past decade, cell cycle regulators have extended their canonical role in cell cycle progression to the regulation of various cellular processes, including cellular metabolism. The regulation of metabolism is intimately connected with the function of autophagy, a catabolic process that promotes the efficient recycling of endogenous components from both extrinsic stress, e.g., nutrient deprivation, and intrinsic sub-lethal damage. Mediating cellular homeostasis and cytoprotection, autophagy is found to be dysregulated in numerous pathophysiological contexts, such as cancer. As an adaptative advantage, the upregulation of autophagy allows tumor cells to integrate stress signals, escaping multiple cell death mechanisms. Nevertheless, the precise role of autophagy during tumor development and progression remains highly context-dependent. Recently, multiple articles has suggested the importance of various cell cycle regulators in the modulation of autophagic processes. Here, we review the current clues indicating that cell-cycle regulators, including cyclin-dependent kinase inhibitors (CKIs), cyclin-dependent kinases (CDKs), and E2F transcription factors, are intrinsically linked to the regulation of autophagy. As an increasing number of studies highlight the importance of autophagy in cancer progression, we finally evoke new perspectives in therapeutic avenues that may include both cell cycle inhibitors and autophagy modulators to synergize antitumor efficacy.

Long Non-Coding RNA Neighbor of BRCA1 Gene 2: A Crucial Regulator in Cancer Biology

Long non-coding RNAs (lncRNAs) are involved in fundamental biochemical and cellular processes. The neighbor of BRCA1 gene 2 (NBR2) is a long intergenic non-coding RNA (lincRNA) whose gene locus is adjacent to the tumor suppressor gene breast cancer susceptibility gene 1 (BRCA1). In human cancers, NBR2 expression is dysregulated and correlates with clinical outcomes. Moreover, NBR2 is crucial for glucose metabolism and affects the proliferation, survival, metastasis, and therapeutic resistance in different types of cancer. Here, we review the precise molecular mechanisms underlying NBR2-induced changes in cancer. In addition, the potential application of NBR2 in the diagnosis and treatment of cancer is also discussed, as well as the challenges of exploiting NBR2 for cancer intervention.

Immunoautophagy-Related Long Noncoding RNA (IAR-lncRNA) Signature Predicts Survival in Hepatocellular Carcinoma

BACKGROUND

The dysregulation of autophagy and immunological processes has been linked to various pathophysiological conditions, including cancer. Most notably, their particular involvement in hepatocellular carcinoma (HCC) is becoming increasingly evident. This has led to the possibility of developing a prognostic signature based on immuno-autophagy-related (IAR) genes. Given that long non-coding RNAs (lncRNAs) also play a special role in HCC, a combined signature utilizing IAR genes and HCC-associated long noncoding RNAs (as IARlncRNA) may potentially help in the clinical scenario.

METHOD

We used Pearson correlation analysis, Kaplan-Meier survival curves, univariate and multivariate Cox regression, and ROC curves to generate and validate a prognostic immuno-autophagy-related long non-coding RNA (IARlncRNA) signature. The Chi-squared test was utilized to investigate the correlation between the obtained signature and the clinical characteristics. CIBERSORT algorithms and the Wilcoxon rank sum test were applied to investigate the correlation between signature and infiltrating immune cells. GO and KEGG analyses were performed to derived signature-dependent pathways.

RESULTS

Herein, we build an IAR-lncRNA signature (as first in the literature) and demonstrate its prognostic ability in hepatocellular carcinoma. Primarily, we identified three IARlncRNAs (MIR210HG, AC099850.3 and CYTOR) as unfavorable prognostic determinants. The obtained signature predicted the high-risk HCC group with shorter overall survival, and was further associated with clinical characteristics such as tumor grade (t = 10.918, p = 0.001). Additionally, several infiltrating immune cells showed varied fractions between the low-risk group and the high-risk HCC groups in association with the obtained signature. In addition, pathways analysis described by the signature clearly distinguishes both risk groups in HCC.

CONCLUSIONS

The immuno-autophagy-related long non-coding RNA (IARlncRNA) signature we established exhibits a prognostic ability in hepatocellular carcinoma. To our knowledge, this is the first attempt in the literature to combine three determinants (immune, autophagy and LnRNAs), thus requiring molecular validation of this obtained signature in clinical samples.

Three dimensions of autophagy in regulating tumor growth: cell survival/death, cell proliferation, and tumor dormancy

Autophagy is an intracellular lysosomal degradation process involved in multiple facets of cancer biology. Various dimensions of autophagy are associated with tumor growth and cancer progression, and here we focus on the dimensions involved in regulation of cell survival/cell death, cell proliferation and tumor dormancy. The first dimension of autophagy supports cell survival under stress within tumors and under certain contexts drives cell death, impacting tumor growth. The second dimension of autophagy promotes proliferation through directly regulating cell cycle or indirectly maintaining metabolism, increasing tumor growth. The third dimension of autophagy facilitates tumor cell dormancy, contributing to cancer treatment resistance and cancer recurrence. The intricate relationship between these three dimensions of autophagy influences the extent of tumor growth and cancer progression. In this review, we summarize the roles of the three dimensions of autophagy in tumor growth and cancer progression, and discuss unanswered questions in these fields.

Autophagy Upregulates miR-449a Expression to Suppress Progression of Colorectal Cancer

Many studies reported that microRNAs (miRNAs) target autophagy-related genes to affect carcinogenesis, however, autophagy-deficiency-related miRNA dysfunction in cancer development remains poorly explored. During autophagic progression, we identified miR-449a as the most up-regulated miRNA. MiR-449a expression was low in the tumor parts of CRC patient specimens and inversely correlated with tumor stage and metastasis with the AUC (area under the curve) of 0.899 and 0.736 as well as poor overall survival rate, indicating that miR-449a has the potential to be a prognostic biomarker. In the same group of CRC specimens, low autophagic activity (low Beclin 1 expression and high p62 accumulation) was detected, which was significantly associated with miR-449a expression. Mechanistic studies disclosed that autophagy upregulates miR-449a expression through degradation of the coactivator p300 protein which acetylates the transcription factor Forkhead Box O1 (FoxO1). Unacetylated FoxO1 translocated to the nucleus and bound to the miR-449a promoter to drive gene expression. Either activation of autophagy by the inducer or overexpression of exogenous miR-449a decreases the expression of target gene LEF-1 and cyclin D1, which lead to decreased proliferation, colony formation, migration, and invasion of CRC cells. Autophagy-miR-449a-tartet genes mediated suppression of tumor formation was further confirmed in the xenograft mouse model. In conclusion, this study reveals a novel mechanism wherein autophagy utilizes miR-449a-LEF1-cyclin D1 axis to suppress CRC tumorigenesis. Our findings open a new avenue toward prognosis and treatment of CRC patients by manipulating autophagy-miR-449a axis.

Myricetin Induces Autophagy and Cell Cycle Arrest of HCC by Inhibiting MARCH1-Regulated Stat3 and p38 MAPK Signaling Pathways

Myricetin is a type of natural flavonol known for its anticancer activity. However, the molecular mechanism of myricetin in anti-hepatocellular carcinoma (HCC) is not well defined. Previous studies indicated that downregulation of membrane-associated RING-CH finger protein 1 (MARCH1) contributed to the treatment of a variety of cancers. Whether the anticancer property of myricetin is associated with MARCH1 expression remains to be investigated. This research explored the anti-HCC mechanism of myricetin. Our results indicate that myricetin induces autophagy and arrests cell cycle at the G2/M phase to suppress the proliferation of HCC cells by downregulating MARCH1. Myricetin reduces MARCH1 protein in Hep3B and HepG2 cells. Interestingly, myricetin upregulates the MARCH1 mRNA level in Hep3B cells but downregulates it in HepG2 cells. The knockdown of MARCH1 by siRNAs (small interfering RNAs) decreases the phosphorylated p38 MAPK (p-p38 MAPK) and Stat3 (p-Stat3), and inhibits HCC cell viability. Moreover, myricetin inhibits p38 MAPK and Stat3 signaling pathways by downregulating MARCH1 to repress HCC growth both in vitro and in vivo. Bafilomycin A1 (BafA1), an autophagy inhibitor, has synergetic effect with myricetin to inhibit HCC growth. Taken together, our results reveal that myricetin inhibits the proliferation of HCC cells by inhibiting MARCH1-regulated p38 MAPK and Stat3 signaling pathways. This research provides a new molecular mechanism for myricetin in anti-HCC and suggests that targeting MARCH1 could be a novel treatment strategy in developing anticancer therapeutics.

Aberrant STAT1 methylation as a non-invasive biomarker in blood of HCV induced hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common types of cancer in the world and a reason behind different oncogenes activation and tumor suppressor genes inactivation. Hyper-methylation of tumor suppressor genes including RASSF1a, GSTP1, p16, and APC cause gene silencing as well as tumor cell invasion. STAT 1 gene is a part of signaling cascade of JAK/STAT and any dysregulation in signaling has been implicated in tumor formation.

OBJECTIVE

The current investigation focus on the methylation role of STAT1 gene as a non-invasive biomarker in the progression and diagnosis of hepatocellular carcinoma.

METHODS

STAT1 gene methylation status in 46 HCV induced hepatocellular carcinoma patients and 40 non-HCC controls were examined by methylation specific PCR. STAT1 gene expression was examined by real time PCR and further validated by various bioinformatics tools.

RESULTS

STAT1 methylation in HCV-induced HCC (67.4%) was significantly higher compared to the non-HCC controls (p< 0.01). However, mRNA expression of STAT1 gene in methylated groups was significantly lower compared to unmethylated groups (p< 0.05). Furthermore, insilco analysis of STAT1 validated our results and shown expression of STAT1 mRNA was lower in liver cancer with the median 24.3 (p= 0.085).

CONCLUSION

After using peripheral blood samples we observed that STAT1 silencing caused by aberrant methylation could be used as potential non-invasive biomarker for the diagnosis of HCV induced hepatocellular carcinoma. We conclude that blood as a sample source could be used instead of biopsy for early detection of HCC.

The Autophagosomes Containing Dengue Virus Proteins and Full-Length Genomic RNA Are Infectious

Autophagic machinery is involved in selective and non-selective recruitment as well as degradation or exocytosis of cargoes, including pathogens. Dengue virus (DENV) infection induces autophagy that enhances virus replication and vesicle release to evade immune system surveillance. This study reveals that DENV2 induces autophagy in lung and liver cancer cells and showed that DENV2 capsid, envelope, NS1, NS3, NS4B and host cell proinflammatory high mobility group box 1 (HMGB1) proteins associated with autophagosomes which were purified by gradient centrifugation. Capsid, NS1 and NS3 proteins showing high colocalization with LC3 protein in the cytoplasm of the infected cells were detected in the purified double-membrane autophagosome by immunogold labeling under transmission electron microscopy. In DENV infected cells, the levels of capsid, envelope, NS1 and HMGB1 proteins are not significantly changed compared to the dramatic accumulation of LC3-II and p62/SQSTM1 proteins when autophagic degradation was blocked by chloroquine, indicating that these proteins are not regulated by autophagic degradation machinery. We further demonstrated that purified autophagosomes were infectious when co-cultured with uninfected cells. Notably, these infectious autophagosomes contain DENV2 proteins, negative-strand and full-length genomic RNAs, but no viral particles. It is possible that the infectivity of the autophagosome originates from the full-length DENV RNA. Moreover, we reveal that DENV2 promotes HMGB1 exocytosis partially through secretory autophagy. In conclusion, we are the first to report that DENV2-induced double-membrane autophagosomes containing viral proteins and full-length RNAs are infectious and not undergoing autophagic degradation. Our novel finding warrants further validation of whether these intracellular vesicles undergo exocytosis to become infectious autophagic vesicles.

Increased expression of Cyclin F in liver cancer predicts poor prognosis: A study based on TCGA database

BACKGROUND

Cyclin F (CCNF) dysfunction has been implicated in various forms of cancer, offering a new avenue for understanding the pathogenic mechanisms underlying hepatocellular carcinoma (HCC). We aimed to evaluate the role of CCNF in HCC using publicly available data from The Cancer Genome Atlas (TCGA).

METHOD

We used TCGA data and Gene Expression Omnibus (GEO) data to analyze the differential expression of CCNF between tumor and adjacent tissues and the relationship between CCNF and clinical characteristics. We compared prognosis of patients with HCC with high and low CCNF expression and constructed receiver operating characteristic (ROC) curves. In addition, we also explored the types of gene mutations in relevant groups and conducted Gene Set Enrichment Analysis (GSEA).

RESULTS

The expression of CCNF in liver cancer tissues was significantly increased compared with that in adjacent tissues, and patients with high CCNF expression had a worse prognosis than those with low CCNF expression. Patients with high CCNF expression also had more somatic mutations. High expression of CCNF hampers the prognosis independently. The GSEA showed that the "http://www.gsea-msigdb.org/gsea/msigdb/cards/BIOCARTA_WNT_PATHWAY" Wnt pathway, "http://www.gsea-msigdb.org/gsea/msigdb/cards/BIOCARTA_P53_PATHWAY" P53 pathway, "http://www.gsea-msigdb.org/gsea/msigdb/cards/HALLMARK_PI3K_AKT_MTOR_SIGNALING" PI3K/Akt/mTOR pathway, "http://www.gsea-msigdb.org/gsea/msigdb/cards/HALLMARK_NOTCH_SIGNALING" Notch pathway were enriched in patients with the high CCNF expression phenotype.

CONCLUSION

High CCNF expression can be seen as an independent risk factor for poor survival in HCC. Its expression may serve as a target for the diagnosis and treatment of liver cancer.

CDK4, CDK6/cyclin-D1 Complex Inhibition and Radiotherapy for Cancer Control: A Role for Autophagy

The expanding clinical application of CDK4- and CDK6-inhibiting drugs in the managements of breast cancer has raised a great interest in testing these drugs in other neoplasms. The potential of combining these drugs with other therapeutic approaches seems to be an interesting work-ground to explore. Even though a potential integration of CDK4 and CDK6 inhibitors with radiotherapy (RT) has been hypothesized, this kind of approach has not been sufficiently pursued, neither in preclinical nor in clinical studies. Similarly, the most recent discoveries focusing on autophagy, as a possible target pathway able to enhance the antitumor efficacy of CDK4 and CDK6 inhibitors is promising but needs more investigations. The aim of this review is to discuss the recent literature on the field in order to infer a rational combination strategy including cyclin-D1/CDK4-CDK6 inhibitors, RT, and/or other anticancer agents targeting G1-S phase cell cycle transition.

Vitamin C affects G0/G1 cell cycle and autophagy by downregulating of cyclin D1 in gastric carcinoma cells

Vitamin C has re-emerged as a promising anticancer agent. This study attempts to analyze the differential gene expression of profiles GSE11919 to look for some clues, and the most significant cell cycle pathway caused by vitamin C was identified by integrated bioinformatics analysis. Inspired by this, we investigated the effect of vitamin C treatment on gastric carcinoma cells by detection of cell cycle, apoptosis, and autophagy. Vitamin C significantly elevated the percentage of cells at G0/G1 phase, whereas the percentage of S phase cells was decreased. Meanwhile, vitamin C treatment resulted in downregulation of cell cycle-related protein Cyclin D1. We deduced that the downregulation of Cyclin D1 by vitamin C accompanied by significantly increased 5'AMP-activated protein kinase and induced autophagy in MKN45 cells. These results suggest that vitamin C has the antiproliferation effect on gastric carcinoma cells via the regulation of cell cycle and autophagy by Cyclin D1.

Circular RNA-DPP4 serves an oncogenic role in prostate cancer progression through regulating miR-195/cyclin D1 axis

BACKGROUND

Recently, more and more studies have highlighted the critical regulatory roles of circular RNAs (circRNAs), a class of non-coding RNAs, in the progression of many human cancers, including prostate cancer (PCa). circRNA microarray analysis was performed to identify circRNAs that are differentially expressed in PCa tissues.

METHODS

104 pairs of PCa tissues and matched adjacent normal prostate tissues (at least 2 cm distal to the tumor margin) were obtained. circRNA microarray analysis was performed on four pairs of PCa tissues and matched adjacent normal prostate tissues to investigate the potential involvement of circRNAs in PCa. Flow cytometric analysis was performed to investigate whether the effect of circDPP4 on PCa cell proliferation was associated with the alteration in cell cycle progression. The role of circDPP4 in PCa tumor growth was further explored in vivo.

RESULTS

We found that circDPP4 was overexpressed in PCa tissues and cell lines, and its expression was closely associated with Gleason score and clinical stage of PCa patients. In vitro loss- and gain-of-function experiments demonstrated that circDPP4 knockdown inhibited, whereas circDPP4 overexpression promoted the proliferation, migration, invasion and cell cycle progression of PCa cells. Knockdown of circDPP4 also suppressed PCa tumor growth in vivo. We further found that circDPP4 functioned as a competing endogenous RNA (ceRNA) for miR-195 in PCa cells, and miR-195 negatively regulated the expression of oncogenic cyclin D1. Rescue experiments suggested that restoration of miR-195 blocked the oncogenic role of circDPP4 in PCa cells.

CONCLUSIONS

Taken together, our findings revealed a novel regulatory mechanism between circDPP4 and miR-195/cyclin D1 axis, and offered novel strategies for the treatment of PCa.

FBX4 mediates rapid cyclin D1 proteolysis upon DNA damage in immortalized esophageal epithelial cells

It has been implied that deregulation of cyclin D1 turnover under stresses can facilitate genomic instability and trigger tumorigenesis. Much focus has been placed on identifying the E3 ligases responsible for mediating cyclin D1 degradation. However, the findings were quite controversial and cell type-dependent. Little is known about how cyclin D1 is regulated in precancerous cells upon DNA damage and which E3 ligases mediate the effects. Here we found cyclin D1 reduction is an early response to DNA damage in immortalized esophageal epithelial cells, with expression dropping to a low level within 1 h after γ-irradiation. Comparison of temporal expression of cyclin D1 upon DNA damage between immortalized NE083-hTERT and NE083-E6E7, the latter being p53/p21-defective, showed that DNA damage-induced rapid cyclin D1 reduction was p53-independent and occurred before p21 accumulation. Overexpression of cyclin D1 in NE083-E6E7 cells could attenuate G0/G1 cell cycle arrest at 1 h after irradiation. Furthermore, rapid reduction of cyclin D1 upon DNA damage was attributed to proteasomal degradation, as evidenced by data showing that proteasomal inhibition by MG132 blocked cyclin D1 reduction while cycloheximide facilitated it. Inhibition of ATM activation and knockdown of E3 ligase adaptor FBX4 reversed cyclin D1 turnover in immortalized NE083-hTERT cells. Further study showed that knockdown of FBX4 facilitated DNA breaks, as indicated by an increase in γ-H2AX foci in esophageal cancer cells. Taken together, the results substantiated a pivotal role of ATM and FBX4 in cyclin D1 proteolysis upon DNA damage in precancerous esophageal epithelial cells, implying that deregulation of the process may contribute to carcinogenesis of esophageal squamous cell carcinoma.

Biological features, gene expression profile, and mechanisms of drug resistance of two- and three-dimensional hepatocellular carcinoma cell cultures

Hepatocellular carcinoma (HCC) is a common malignant tumor with insidious onset and rapid progression. Its treatment is often difficult owing to tumor resistance. In this study, we aimed to understand the different biological characteristics, gene expression profiles, and drug resistance mechanisms of HCC cells cultured under different conditions. A conventional adherence method and a liquid overlay technique were used to prepare two- and three-dimensional cultures of Bel-7402 and 5-fluorouracil (5-Fu)-resistant Bel-7402 (Bel-7402/5-Fu) cells. Morphological characteristics were assessed via microscopy, and cell cycle distribution and apoptotic rate were obtained using flow cytometry. Cell sensitivity to different concentrations of drugs was detected with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. Gene expression profiles and signal transduction pathways of Bel-7402 and Bel-7402/5-Fu cells under different culture conditions were determined using gene chips. Cells in three-dimensional culture were suspended and they grew into dense multicellular spheroid (MCS) structures, aggregating with each other. In contrast to cells in the two-dimensional culture, cell cycle arrest was observed in MCSs. The sensitivity of Bel-7402 cells in the two-dimensional culture to drugs at high concentrations was significantly higher than that of cells in the three-dimensional culture (p < .05). The apoptotic rate of Bel-7402 and Bel-7402/5-Fu cells was also higher in the two-dimensional culture (p < .05). Signal transduction pathway analysis showed that after Bel-7402 cells acquired resistance to 5-Fu, CCND1, MCM2, and MCM3 gene expression was upregulated in the G1 to S cell cycle control signal transduction pathway, CDKN1C and CCNG2 gene expression was downregulated, and MCM2 and MCM3 gene expression was upregulated in the DNA replication signal transduction pathway. Therefore, the liquid overlay technique is a simple, low-cost procedure to successfully construct three-dimensional culture models of HCC. This study provides new information and methods for exploring the molecular mechanisms of liver cancer resistance, clinical treatment, development of molecular information, and interventional prevention.

LETM1 Knockdown Promotes Autophagy and Apoptosis Through AMP-Activated Protein Kinase Phosphorylation-Mediated Beclin-1/Bcl-2 Complex Dissociation in Hepatocellular Carcinoma

Leucine zipper/EF hand-containing transmembrane-1 (LETM1) is an inner mitochondrial membrane protein that has been reported to be involved in many primary tumors and may regulate many biological processes. However, the biological role and molecular mechanism of LETM1 in the progression of hepatocellular carcinoma (HCC) remain largely unknown. In this study, we found that LETM1 was highly expressed in HCC tissues and cell lines and that higher LETM1 expression was associated with a lower overall survival rate in HCC patients. In addition, knockdown of LETM1 inhibited proliferation and enhanced apoptosis and autophagy in the Huh 7 and QGY-7701 liver cancer cell lines. Mechanistically, knockdown of LETM1 dissociated the Beclin-1/Bcl-2 complex through phosphorylation of AMPK and Bcl-2. These results demonstrated that LETM1 is involved in the development of HCC and could be a novel therapeutic target in HCC.

Prenatal dexamethasone exposure caused fetal rats liver dysplasia by inhibiting autophagy-mediated cell proliferation

As a synthetic glucocorticoid, dexamethasone has been widely used in the clinical treatment of premature birth and related pregnant diseases, but its clinical use is still controversial due to developmental toxicity. This study aimed to confirm the proliferation inhibitory effect of pregnant dexamethasone exposure (PDE) on fetal liver development and elucidate its molecular mechanism. In vitro studies, we found that dexamethasone inhibited hepatocyte proliferation through autophagy activated by glucocorticoid receptor (GR)-forkhead protein O1 (FOXO1) pathway. Subsequently, in vivo, we confirmed in a PDE rat model that male fetal liver proliferation was inhibited, and the expression of the GR-FOXO1 pathway and autophagy were increased. Taken together, PDE induces autophagy by activating the GR-FOXO1 pathway, which leads to fetal liver proliferation inhibition and dysplasia in offspring rats. This study confirmed that dexamethasone activates cell autophagy in utero through the GR-FOXO1 pathway, thereby inhibiting hepatocyte proliferation and liver development, which provides theoretical basis for understanding the developmental toxicity of dexamethasone and guiding the rational clinical use.

LncRNA NBR2 inhibits tumorigenesis by regulating autophagy in hepatocellular carcinoma

Long noncoding RNAs (lncRNAs) have been identified to play increasingly important roles in tumorigenesis, and they may serve as novel biomarkers for cancer therapy. LncRNA NBR2 (neighbor of BRCA1 gene 2), a novel identified lncRNA, is demonstrated to decrease in several cancers. However, it is still unknown whether lncRNA NBR2 is involved in hepatocellular carcinoma and autophagy. We found that HCC cases with lower NBR2 expression had significantly worse overall survival than those with higher NBR2 expression in advanced patients. And the expression of NBR2 was negatively correlated with the degree of malignancy of HCC cell lines and differentiation of hepatocellular carcinoma. Besides, NBR2 inhibited the proliferation, invasion, and migration of liver cancer cells. We further found that NBR2 repressed cytoprotective autophagy to restrain HCC cell proliferation. Moreover, NBR2 inhibited Beclin 1-dependent autophagy through ERK and JNK pathways. Taken together, NBR2 suppressed autophagy-induced cell proliferation at least partly through ERK and JNK pathways. These data indicated that NBR2 served as a tumor suppressor gene in hepatocellular carcinoma. The current study provides a novel insight and treatment strategy for hepatocellular carcinoma.

Cyclin D1 in Cancer: A Molecular Connection for Cell Cycle Control, Adhesion and Invasion in Tumor and Stroma

Cyclin D1, an important regulator of cell cycle, carries out a central role in the pathogenesis of cancer determining uncontrolled cellular proliferation. In normal cells, Cyclin D1 expression levels are strictly regulated, conversely, in cancer, its activity is intensified in various manners. Different studies demonstrate that CCDN1 gene is amplified in several tumor types considering it as a negative prognostic marker of this pathology. Cyclin D1 is known for its role in the nucleus, but recent clinical studies associate the amount located in the cytoplasmic membrane with tumor invasion and metastasis. Cyclin D1 has also other functions: it governs the expression of specific miRNAs and it plays a crucial role in the tumor-stroma interactions potentiating most of the cancer hallmarks. In the present review, we will summarize the current scientific evidences that highlight the involvement of Cyclin D1 in the pathogenesis of different types of cancer, best of all in breast cancer. We will also focus on recent insights regarding the Cyclin D1 as molecular bridge between cell cycle control, adhesion, invasion, and tumor/stroma/immune-system interplay in cancer.

Screening and Identification of Potential Biomarkers in Hepatitis B Virus-Related Hepatocellular Carcinoma by Bioinformatics Analysis

Hepatocellular carcinoma (HCC) is one of the most lethal cancers globally. Hepatitis B virus (HBV) infection might cause chronic hepatitis and cirrhosis, leading to HCC. To screen prognostic genes and therapeutic targets for HCC by bioinformatics analysis and determine the mechanisms underlying HBV-related HCC, three high-throughput RNA-seq based raw datasets, namely GSE25599, GSE77509, and GSE94660, were obtained from the Gene Expression Omnibus database, and one RNA-seq raw dataset was acquired from The Cancer Genome Atlas (TCGA). Overall, 103 genes were up-regulated and 127 were down-regulated. A protein–protein interaction (PPI) network was established using Cytoscape software, and 12 pivotal genes were selected as hub genes. The 230 differentially expressed genes and 12 hub genes were subjected to functional and pathway enrichment analyses, and the results suggested that cell cycle, nuclear division, mitotic nuclear division, oocyte meiosis, retinol metabolism, and p53 signaling-related pathways play important roles in HBV-related HCC progression. Further, among the 12 hub genes, kinesin family member 11 (KIF11), TPX2 microtubule nucleation factor (TPX2), kinesin family member 20A (KIF20A), and cyclin B2 (CCNB2) were identified as independent prognostic genes by survival analysis and univariate and multivariate Cox regression analysis. These four genes showed higher expression levels in HCC than in normal tissue samples, as identified upon analyses with Oncomine. In addition, in comparison with normal tissues, the expression levels of KIF11, TPX2, KIF20A, and CCNB2 were higher in HBV-related HCC than in HCV-related HCC tissues. In conclusion, our results suggest that KIF11, TPX2, KIF20A, and CCNB2 might be involved in the carcinogenesis and development of HBV-related HCC. They can thus be used as independent prognostic genes and novel biomarkers for the diagnosis of HBV-related HCC and development of pertinent therapeutic strategies.

The dichotomous role of TGF-β in controlling liver cancer cell survival and proliferation

Hepatocellular carcinoma (HCC) is the major form of primary liver cancer and one of the most prevalent and life-threatening malignancies globally. One of the hallmarks in HCC is the sustained cell survival and proliferative signals, which are determined by the balance between oncogenes and tumor suppressors. Transforming growth factor beta (TGF-β) is an effective growth inhibitor of epithelial cells including hepatocytes, through induction of cell cycle arrest, apoptosis, cellular senescence, or autophagy. The antitumorigenic effects of TGF-β are bypassed during liver tumorigenesis via multiple mechanisms. Furthermore, along with malignant progression, TGF-β switches to promote cancer cell survival and proliferation. This dichotomous nature of TGF-β is one of the barriers to therapeutic targeting in liver cancer. Thereafter, understanding the underlying molecular mechanisms is a prerequisite for discovering novel antitumor drugs that may specifically disable the growth-promoting branch of TGF-β signaling or restore its tumor-suppressive arm. This review summarizes how TGF-β inhibits or promotes liver cancer cell survival and proliferation, highlighting the functional switch mechanisms during the process.

The novel interplay between CD44 standard isoform and the caspase-1/IL1B pathway to induce hepatocellular carcinoma progression

Accumulating data indicate caspase-1 (CASP1), one of the inflammatory caspases, promotes hepatocellular carcinoma (HCC) progression in tumor proliferation, invasion, EMT phenotype and sorafenib resistance. However, the molecular basis of regulating caspase-1 expression and caspase-1/IL1B (interleukin-1β) pathway in HCC remains unclear. Here, we demonstrated the novel interplay between caspase-1/IL1B activation and cluster differentiation 44 standard isoform (CD44s) in HCC. In this study, we observed that CD44s is responsible for caspase-1/IL1B activation both in HCC tissues and five HCC cell lines. In normoxia conditions, CD44s knockdown repressed the activation of caspase-1/IL1B via stimulating AMPK-mediated autophagy. Moreover, our data suggested that p62-induced autophagic degradation of caspase-1 accounted for caspase-1/IL1B inactivation in CD44s deficient cells. Administration of recombinant human IL1B could rescue impaired proliferation, invasion, and EMT phenotype in CD44s deficient HCC cells. Lastly, hypoxia-mediated caspase-1/IL1B overexpression could be abolished by CD44s downregulation through decreasing HIF1A and enhancing autophagic activity. Overall, targeting CD44s is a novel inhibitory mechanism of caspase-1/IL1B expression, both in normoxia and hypoxia conditions.