DEPTOR inhibits cell proliferation and confers sensitivity to dopamine agonist in pituitary adenoma

Ubiquitination regulates autophagy in cancer: simple modifications, promising targets

Autophagy is an important lysosomal degradation process that digests and recycles bio-molecules, protein or lipid aggregates, organelles, and invaded pathogens. Autophagy plays crucial roles in regulation of metabolic and oxidative stress and multiple pathological processes. In cancer, the role of autophagy is dual and paradoxical. Ubiquitination has been identified as a key regulator of autophagy that can influence various steps in the autophagic process, with autophagy-related proteins being targeted for ubiquitination, thus impacting cancer progression and the effectiveness of therapeutic interventions. This review will concentrate on mechanisms underlying autophagy, ubiquitination, and their interactions in cancer, as well as explore the use of drugs that target the ubiquitin-proteasome system (UPS) and ubiquitination process in autophagy as part of cancer therapy.

GHSR deficiency exacerbates Parkinson's disease pathology by impairing autophagy

In Parkinson's disease (PD), exogenous ghrelin protects dopaminergic neurons through its receptor, growth hormone secretagogue receptor (GHSR). However, in contrast to the strikingly low levels of ghrelin, GHSR is highly expressed in the substantia nigra (SN). What role does GHSR play in dopaminergic neurons is unknown. In this study, using GHSR knockout mice (Ghsr-/- mice) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD model, we found that GHSR deletion aggravated dopaminergic neurons degeneration, and the expression and activity of GHSR were significantly reduced in PD. Furthermore, we explored the potential mechanism that GHSR deficiency aggregated PD-related neurodegeneration. We showed that DEPTOR, a subunit of mTORC1, was overexpressed in Ghsr-/- mice, positively regulating autophagy and enhancing autophagy initiation. The expression of lysosomal markers was abnormal, implying lysosomal dysfunction. As a result, the damaged mitochondria could not be effectively eliminated, which ultimately exacerbated the injury of nigral dopaminergic neurons. In particular, we demonstrated that DEPTOR could be transcriptionally regulated by KLF4. Specific knockdown of KLF4 in dopaminergic neurons effectively alleviated neurodegeneration in Ghsr-/- mice. In summary, our results suggested that endogenous GHSR deletion-compromised autophagy by impairing lysosomal function, is a key contributor to PD, which provided ideas for therapeutic approaches involving the manipulation of GHSR.

Identification and Validation of Genes Related to Macrophage Polarization and Cell Death Modes Under Mycobacterium tuberculosis Infection

Purpose

To investigate the correlation between M1/M2 macrophages (M1/M2 Mφ) and cell death mode under Mycobacterium tuberculosis (Mtb) infection.

Methods

Raw gene expression profiles were collected from the Gene Expression Omnibus (GEO) database. Genes related to different cell death modes were collected from the KEGG, FerrDb and GSEA databases. The differentially expressed genes (DEGs) of the gene expression profiles were identified using the limma package in R. The intersection genes of M1/M2 Mφ with different cell death modes were obtained by the VennDiagram package. Hub genes were obtained by constructing the protein-protein interactions (PPI) network and Receiver Operating Characteristic (ROC) curve analysis. The expression of cell death modes marker genes and Hub genes were verified by Western Blot and Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR).

Results

Bioinformatics analysis was performed to screen Hub genes of Mtb-infected M1 Mφ and different cell death modes, naming NFKB1, TNF, CFLAR, TBK1, IL6, RELA, SOCS1, AIM2; Hub genes of Mtb-infected M2 Mφ and different cell death modes, naming TNF, BIRC3, MAP1LC3C, DEPTOR, UVRAG, SOCS1. Combined with experimental validation, M1 Mφ under Mtb infection showed higher expression of death (including apoptosis, autophagy, ferroptosis, and pyroptosis) genes compared to M2 Mφ and genes such as NFKB1, TNF, CFLAR, TBK1, IL6, RELA, AIM2, BIRC3, DEPTOR show differential expression.

Conclusion

NFKB1, TNF, CFLAR, TBK1, IL6, RELA, AIM2 in Mtb-infected M1 Mφ, and TNF, BIRC3, DEPTOR in Mtb-infected M2 Mφ might be used as potential diagnostic targets for TB. At early stage of Mtb infection, apoptosis, autophagy, ferroptosis, and pyroptosis occurred more significantly in M1 Mφ than that in M2 Mφ, which may contribute to the transition of Mtb-infected Mφ from M1-dominant to M2-dominant and contribute to the immune escape mechanisms of Mtb.

Sestrin2 maintains hepatic immune homeostasis and redox balance partially via inhibiting RIPK3-mediated necroptosis in metabolic dysfunction-associated steatohepatitis

BACKGROUND & AIMS

Necroptosis, a novel type of programmed cell death, is intricately associated with inflammatory response. Currently, most studies focus on the activation of necroptosis, while the mechanisms underlying the negative regulation of necroptosis remain poorly understood.

METHODS

The effects of sestrin2 (SESN2) overexpression or knockdown on the regulation of necroptosis were assessed in the TNFα/Smac-mimetic/Z-VAD-FMK (T/S/Z)-induced necroptosis model and palmitic acid (PA)-induced lipotoxicity model. Western-blot, co-Immunoprecipitation, Glutathione S-transferase pull-down, and confocal assays were employed to explore the regulatory mechanisms including protein-protein interactions and post-translational modification. Furthermore, we used GSK'872, a specific inhibitor of receptor-interacting serine/threonine-protein kinase (RIPK) 3, to evaluate the relationship between SESN2-related alterations and RIPK3-mediated necroptosis in T/S/Z-induced necroptosis model, PA-induced lipotoxicity model, and high-fat high-cholesterol diet (HFHCD)-induced non-alcoholic steatohepatitis model.

RESULTS

Our findings revealed that SESN2 was upregulated under conditions that induce necroptosis and functioned as a negative regulator of necroptosis. High levels of SESN2 could equipped hepatocytes with the ability to defend against necroptotic inflammation and oxidative stress. Mechanistically, SESN2 interacted with RIPK3 and tuned down necroptosis by inhibiting the phosphorylation of RIPK3, promoting the ubiquitination of RIPK3, and preventing the formation of the RIPK1/RIPK3 necrosome. The depletion of SESN2 resulted in excessive necroptosis, accompanied by increased fat accumulation, inflammation, and oxidative stress in the experimental steatohepatitis model. Blocking necroptosis by GSK'872 reduced the liberation of pro-inflammatory cytokines and reactive oxygen species generation, but not hepatocyte fat deposition, in both PA-treated SESN2 knockout cells and HFHCD-fed SESN2 knockout mice, suggesting that the activation of RIPK3-mediated necroptosis may partially account for the hyperinflammation and excessive oxidative stress induced by SESN2 deficiency.

CONCLUSION

Our results suggested that SESN2 inhibited RIPK3-mediated necroptosis; this regulation is an important for the immune homeostasis and the redox balance in the liver.

Aggressive PitNETs and Potential Target Therapies: A Systematic Review of Molecular and Genetic Pathways

Recently, advances in molecular biology and bioinformatics have allowed a more thorough understanding of tumorigenesis in aggressive PitNETs (pituitary neuroendocrine tumors) through the identification of specific essential genes, crucial molecular pathways, regulators, and effects of the tumoral microenvironment. Target therapies have been developed to cure oncology patients refractory to traditional treatments, introducing the concept of precision medicine. Preliminary data on PitNETs are derived from preclinical studies conducted on cell cultures, animal models, and a few case reports or small case series. This study comprehensively reviews the principal pathways involved in aggressive PitNETs, describing the potential target therapies. A search was conducted on Pubmed, Scopus, and Web of Science for English papers published between 1 January 2004, and 15 June 2023. 254 were selected, and the topics related to aggressive PitNETs were recorded and discussed in detail: epigenetic aspects, membrane proteins and receptors, metalloprotease, molecular pathways, PPRK, and the immune microenvironment. A comprehensive comprehension of the molecular mechanisms linked to PitNETs' aggressiveness and invasiveness is crucial. Despite promising preliminary findings, additional research and clinical trials are necessary to confirm the indications and effectiveness of target therapies for PitNETs.

DEPTOR as a novel prognostic marker inhibits the proliferation via deactivating mTOR signaling pathway in gastric cancer cells

Aberrantly activated mTOR signaling pathway is commonly found in malignancies including gastric cancer (GC). DEPTOR, as a naturally occurred inhibitor of mTOR, functions in the pro- or anti-tumor manner depending on distinct tumor contexts. However, the roles of DEPTOR in GC remain largely unknown. In this study, DEPTOR expression was identified to be significantly decreased in GC tissues compared with matched normal gastric tissues, and reduced DEPTOR level was indicative of poor prognosis in patients. Restored DEPTOR expression inhibited the propagation in AGS and NCI-N87 cells, whose DEPTOR levels are low, via deactivating mTOR signaling pathway. Likewise, cabergoline (CAB) attenuated the proliferation in AGS and NCI-N87 cells via partially rescuing DEPTOR protein level. Targeted metabolomics analysis showed that several key metabolites, such as l-serine, significantly changed in AGS cells with DEPTOR restoration. These results revealed the anti-proliferation function of DEPTOR in GC cells, suggesting that restored DEPTOR expression using CAB may be a potential therapeutic approach for patients with GC.

The UBE2C/CDH1/DEPTOR axis is an oncogene and tumor suppressor cascade in lung cancer cells

Ubiquitin-conjugating enzyme E2C (UBE2C) mediates ubiquitylation chain formation via the K11 linkage. While previous in vitro studies showed that UBE2C plays a growth-promoting role in cancer cell lines, the underlying mechanism remains elusive. Still unknown is whether and how UBE2C plays a promoting role in vivo. Here we report that UBE2C was indeed essential for growth and survival of lung cancer cells harboring Kras mutations, and UBE2C was required for KrasG12D-induced lung tumorigenesis, since Ube2c deletion significantly inhibited tumor formation and extended the lifespan of mice. Mechanistically, KrasG12D induced expression of UBE2C, which coupled with APC/CCDH1 E3 ligase to promote ubiquitylation and degradation of DEPTOR, leading to activation of mTORC signaling. Importantly, DEPTOR levels fluctuated during cell cycle progression in a manner dependent on UBE2C and CDH1, indicating their physiological connection. Finally, Deptor deletion fully rescued the tumor inhibitory effect of Ube2c deletion in the KrasG12D lung tumor model, indicating a causal role of Deptor. Taken together, our study shows that the UBE2C/CDH1/DEPTOR axis forms an oncogene and tumor suppressor cascade that regulates cell cycle progression and autophagy and validates UBE2C an attractive target for lung cancer associated with Kras mutations.

DFNA5 inhibits colorectal cancer proliferation by suppressing the mTORC1/2 signaling pathways via upregulation of DEPTOR

The human deafness, autosomal dominant 5 gene (DFNA5), a newly discovered executor of pyroptosis, has been strongly implicated in the tumorigenesis of several human cancers. However, an understanding of the functional role of DFNA5 in the development and progression of colorectal cancer (CRC) is limited. In this study, we demonstrated that DFNA5 was downregulated in CRC tissues. Ectopic expression of DFNA5 inhibited tumor cell growth in vitro, retarded tumor formation in vivo, and blocked a cell-cycle transition from the G0/G1 to the S phase, whereas a DFNA5 knockdown promoted cell proliferation. Western blotting showed that the levels of cell cycle-related proteins, including cyclin D1, cyclin E, CDK2, and p21, were accordingly altered upon DFNA5 overexpression or DFNA5 knockdown. Mechanistic studies indicated that DFNA5 exerted its tumor suppressor functions by antagonizing mTORC1/2 signaling via upregulation of DEPTOR. In addition, blockage of mTORC1/2 signaling by Torin-1 abolished the accelerative proliferation by DFNA5 knockdown. In conclusion, these results indicated that DFNA5 inhibits the proliferation and tumor formation of colon cancer cells by suppressing mTORC1/2 signaling.

TRIM65 determines the fate of a novel subtype of pituitary neuroendocrine tumors via ubiquitination and degradation of TPIT

BACKGROUND

Pituitary neuroendocrine tumors (PitNETs) are common intracranial tumors that are classified into seven histological subtypes, including lactotroph, somatotroph, corticotroph, thyrotroph, gonadotroph, null cell, and plurihormonal PitNETs. However, the molecular characteristics of these types of PitNETs are not completely clear.

METHODS

A total of 180 consecutive cases of PitNETs were collected to perform RNA sequencing. All subtypes of PitNETs were distinguished by unsupervised clustering analysis. We investigated the regulation of TPIT by TRIM65 and its effects on ACTH production and secretion in ACTH-secreting pituitary cell lines, as well as in murine models using biochemical analyses, confocal microscopy, and luciferase reporter assays.

RESULTS

A novel subtype of PitNETs derived from TPIT lineage cells was identified as with normal TPIT transcription but with lowered protein expression. Furthermore, for the first time, TRIM65 was identified as the E3 ubiquitin ligase of TPIT. Depending on the RING domain, TRIM65 ubiquitinated and degraded the TPIT protein at multiple Lys sites. In addition, TRIM65-mediated ubiquitination of TPIT inhibited POMC transcription and ACTH production to determine the fate of the novel subtype of PitNETs in vitro and in vivo.

CONCLUSION

Our studies provided a novel classification of PitNETs and revealed that the TRIM65-TPIT complex controlled the fate of the novel subtype of PitNETs, which provides a potential therapy target for Cushing's disease.

N6-Methyladenosine-Related LncRNAs Are Potential Remodeling Indicators in the Tumor Microenvironment and Prognostic Markers in Osteosarcoma

N6-Adenosine methylation, yielding N6-methyladenosine (m⁶A), is a reversible epigenetic modification found in messenger RNAs and long non-coding RNAs (lncRNAs), which affects the fate of modified RNA molecules and is essential for the development and differentiation of immune cells in the tumor microenvironment (TME). Osteosarcoma (OS) is the most common primary bone tumor in children and adolescents, and is characterized by high mortality. Currently, the possible role of m⁶A modifications in the prognosis of OS is unclear. In the present study, we investigated the correlation between m⁶A-related lncRNA expression and the clinical outcomes of OS patients via a comprehensive analysis. Clinical and workflow-type data were obtained from the Genotype-Tissue Expression Program and The Cancer Genome Atlas. We examined the relationship between m⁶A modifications and lncRNA expression, conducted Kyoto Encyclopedia of Genes analysis and also gene set enrichment analysis (GSEA), implemented survival analysis to investigate the association of clinical survival data with the expression of m⁶A-related lncRNAs, and utilized Lasso regression to model the prognosis of OS. Furthermore, we performed immune correlation analysis and TME differential analysis to investigate the infiltration levels of immune cells and their relationship with clinical prognosis. LncRNA expression and m⁶A levels were closely associated in co-expression analysis. The expression of m⁶A-related lncRNAs was quite low in tumor tissues; this appeared to be a predicting factor of OS in a prognostic model, independent of other clinical features. The NOD-like receptor signaling pathway was the most significantly enriched pathway in GSEA. In tumor tissues, SPAG4 was overexpressed while ZBTB32 and DEPTOR were downregulated. Tissues in cluster 2 were highly infiltrated by plasma cells. Cluster 2 presented higher ESTIMATE scores and stromal scores, showing a lower tumor cell purity in the TME. In conclusion, m⁶A-related lncRNA expression is strongly associated with the occurrence and development of OS, and can be used to as a prognostic factor of OS. Moreover, m⁶A-related lncRNAs and infiltrating immune cells in the TME could serve as new therapeutic targets and prognostic biomarkers for OS.

MicroRNAs in Dopamine Agonist-Resistant Prolactinoma

Dopamine agonists (DAs) are preferred for the treatment of prolactinomas and are usually very effective. Nonetheless, 20-30% of bromocriptine- and approximately 10% of cabergoline-treated individuals exhibit resistance to DAs. In addition, the mechanism underlying this phenomenon remains elusive. In this study, we summarize the major findings regarding the role of microRNAs (miRNAs) in the pathogenesis of DA-resistant prolactinoma (DARP). Currently available evidence suggests that miRNAs are usually dysregulated in DARP and that, although controversial, the dysregulated miRNAs target the transforming growth factor (TGF)-β, dopamine 2 receptor (D2R), or estradiol (E2)/estrogen receptor (ER) signaling pathways to mediate the therapeutic effect of DAs. These findings provide new incentives for research on innovative strategies for predicting patients' responsiveness to dopamine therapies and for developing treatment approaches. Unfortunately, recent studies tended to focus exclusively on the differential miRNA expression profiles between DARP and dopamine-sensitive prolactinoma, and no definitive consensus has been reached regarding the role of these miRNAs in the modulation mechanism. Therefore, current and future efforts should be directed toward the exploration of the mechanism underlying the dysregulation of miRNAs as well as of the target proteins that are affected by the dysregulated miRNAs. Furthermore, the modulation of the expression of dysregulated miRNAs, which target the D2R, TGF-β, or E2/ER signaling pathways, might be a promising alternative to treat patients with DARP and improve their prognosis.

Autophagy: a multifaceted player in the fate of sperm

BACKGROUND

Autophagy is an intracellular catabolic process of degrading and recycling proteins and organelles to modulate various physiological and pathological events, including cell differentiation and development. Emerging data indicate that autophagy is closely associated with male reproduction, especially the biosynthetic and catabolic processes of sperm. Throughout the fate of sperm, a series of highly specialized cellular events occur, involving pre-testicular, testicular and post-testicular events. Nonetheless, the most fundamental question of whether autophagy plays a protective or harmful role in male reproduction, especially in sperm, remains unclear.

OBJECTIVE AND RATIONALE

We summarize the functional roles of autophagy in the pre-testicular (hypothalamic–pituitary–testis (HPG) axis), testicular (spermatocytogenesis, spermatidogenesis, spermiogenesis, spermiation) and post-testicular (sperm maturation and fertilization) processes according to the timeline of sperm fate. Additionally, critical mechanisms of the action and clinical impacts of autophagy on sperm are identified, laying the foundation for the treatment of male infertility.

SEARCH METHODS

In this narrative review, the PubMed database was used to search peer-reviewed publications for summarizing the functional roles of autophagy in the fate of sperm using the following terms: ‘autophagy’, ‘sperm’, ‘hypothalamic–pituitary–testis axis’, ‘spermatogenesis’, ‘spermatocytogenesis’, ‘spermatidogenesis’, ‘spermiogenesis’, ‘spermiation’, ‘sperm maturation’, ‘fertilization’, ‘capacitation’ and ‘acrosome’ in combination with autophagy-related proteins. We also performed a bibliographic search for the clinical impact of the autophagy process using the keywords of autophagy inhibitors such as ‘bafilomycin A1’, ‘chloroquine’, ‘hydroxychloroquine’, ‘3-Methyl Adenine (3-MA)’, ‘lucanthone’, ‘wortmannin’ and autophagy activators such as ‘rapamycin’, ‘perifosine’, ‘metformin’ in combination with ‘disease’, ‘treatment’, ‘therapy’, ‘male infertility’ and equivalent terms. In addition, reference lists of primary and review articles were reviewed for additional relevant publications. All relevant publications until August 2021 were critically evaluated and discussed on the basis of relevance, quality and timelines.

OUTCOMES

(i) In pre-testicular processes, autophagy-related genes are involved in the regulation of the HPG axis; and (ii) in testicular processes, mTORC1, the main gate to autophagy, is crucial for spermatogonia stem cell (SCCs) proliferation, differentiation, meiotic progression, inactivation of sex chromosomes and spermiogenesis. During spermatidogenesis, autophagy maintains haploid round spermatid chromatoid body homeostasis for differentiation. During spermiogenesis, autophagy participates in acrosome biogenesis, flagella assembly, head shaping and the removal of cytoplasm from elongating spermatid. After spermatogenesis, through PDLIM1, autophagy orchestrates apical ectoplasmic specialization and basal ectoplasmic specialization to handle cytoskeleton assembly, governing spermatid movement and release during spermiation. In post-testicular processes, there is no direct evidence that autophagy participates in the process of capacitation. However, autophagy modulates the acrosome reaction, paternal mitochondria elimination and clearance of membranous organelles during fertilization.

WIDER IMPLICATIONS

Deciphering the roles of autophagy in the entire fate of sperm will provide valuable insights into therapies for diseases, especially male infertility.

Co-treatment With Everolimus, an mTOR-Specific Antagonist, or Downregulation of ELK1 Enhances the Sensitivity of Pancreatic Cancer Cells to Genistein

Genistein is a natural isoflavone with pharmacological or potentially anti-tumor properties. However, the resistance of cancer cells to genistein remains a major obstacle. This study focused on the mechanism implicated in the resistance of pancreatic cancer (PC) cells to genistein and the mechanism of action. First, key molecules and signaling pathways related to genistein resistance in PC cells were explored using bioinformatics tools. DEP domain containing MTOR interacting protein (DEPTOR), a typical inhibitor of the mammalian target of rapamycin (mTOR) signaling, was predicted to be poorly expressed in the genistein-resistant PC cells. Thereafter, genistein-resistant PC cells (Panc-1 and PaCa) were constructed. Altered expression of DEPTOR was introduced in cells, and everolimus (ELM), an mTOR-specific antagonist, was administrated in cells as well to examine their roles in genistein resistance. The cell apoptosis was examined in vitro and in vivo in mouse xenograft tumors. The upstream regulator of DEPTOR was predicted via bioinformatic tools. The bioinformatic analyses showed that the PI3K/AKT/mTOR signaling pathway was activated in the setting of DEPTOR downregulation in genistein-resistant PC cells. DEPTOR overexpression reduced the 50% inhibiting concentration (IC50) of genistein in PC cells and suppressed mTOR phosphorylation, and it increased caspase-3 activity, LDH release and apoptosis in PC cells. ELM treatment enhanced the sensitivity of PC cells to genistein in vitro and it strengthened the tumor-eliminating role of genistein in mice. ETS transcription factor ELK1 (ELK1), a transcription factor that negatively regulated DEPTOR transcription, was suppressed by genistein. Upregulation of ELK1 suppressed DEPTOR transcription and reduced the genistein sensitivity of cells, and it also blocked the genistein-sensitizing roles of ELM in PC cells. In conclusion, this study demonstrated that ELK1 reduces DEPTOR transcription, leading to mTOR phosphorylation and the drug resistance of PC cells.

Brusatol Inhibits Tumor Growth and Increases the Efficacy of Cabergoline against Pituitary Adenomas

Cabergoline (CAB) is the first choice for treatment of prolactinoma and the most common subtype of pituitary adenoma. However, drug resistance and lack of effectiveness in other pituitary tumor types remain clinical challenges to this treatment. Brusatol (BT) is known to inhibit cell growth and promote apoptosis in a variety of cancer cells. In our present studies, we investigate the effects of BT on pituitary tumor cell proliferation in vitro and in vivo. BT treatment resulted in an increase in Annexin V-expressing cells and promoted the expression of apoptosis-related proteins in rat and human pituitary tumor cells. Investigation of the mechanism underlying this effect revealed that BT increased the production of reactive oxygen species (ROS) and inhibited the phosphorylation of 4EBP1 and S6K1. Furthermore, treatment with a combination of BT and CAB resulted in greater antitumor effects than either treatment alone in nude mice and pituitary tumor cells. Collectively, our results suggest that the BT-induced ROS accumulation and inhibition of mTORC1 signaling pathway leads to inhibition of tumor growth. Combined use of CAB and BT may increase the clinical effectiveness of treatment for human pituitary adenomas.

Co-amplification of genes in chromosome 8q24: a robust prognostic marker in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is a leading cause of tumor-associated death worldwide, owing to its high 5-year postoperative recurrence rate and inter-individual heterogeneity. Thus, a prognostic model is urgently needed for patients with HCC. Several researches have reported that copy number amplification of the 8q24 chromosomal region is associated with low survival in many cancers. In the present work, we set out to construct a multi-gene model for prognostic prediction in HCC.

Methods

RNA sequencing and copy number variant data of tumor tissue samples of HCC from The Cancer Genome Atlas (n=328) were used to identify differentially expressed messenger RNAs of genes located on the chromosomal 8q24 region by the Wilcox test. Univariate Cox and Lasso-Cox regression analyses were carried out for the screening and construction of a prognostic multi-gene signature in The Cancer Genome Atlas cohort (n=119). The multi-gene signature was validated in a cohort from the International Cancer Genome Consortium (n=240). A nomogram for prognostic prediction was built, and the underpinning molecular mechanisms were studied by Gene Set Enrichment Analysis.

Results

We successfully established a 7-gene prognostic signature model to predict the prognosis of patients with HCC. Using the model, we divided individuals into high-risk and low-risk sets, which showed a significant difference in overall survival in the training dataset (HR =0.17, 95% CI: 0.1-0.28; P<0.001) and in the testing dataset (HR = 0.42, 95% CI: 0.23-0.74; P=0.002). Multivariate Cox regression analysis showed the signature to be an independent prognostic factor of HCC survival. A nomogram including the prognostic signature was constructed and showed a better predictive performance in short-term (1 and 3 years) than in long-term (5 years) survival. Furthermore, Gene Set Enrichment Analysis identified several pathways of significance, which may aid in explaining the underlying molecular mechanism.

Conclusions

Our 7-gene signature is a reliable prognostic marker for HCC, which may provide meaningful information for therapeutic customization and treatment-related decision making.

Autophagy in normal pituitary and pituitary tumor cells and its potential role in the actions of somatostatin receptor ligands in acromegaly

Autophagy is an evolutionary conserved process for the self-degradation and recycling of cellular components in the cytoplasm. It is involved in both physiological and pathological conditions. In detail, the term "autophagy" refers to intracellular degradative pathways that lead to packaging and deliver of cellular components to lysosomes or to plant and yeast vacuoles. Autophagy is triggered by a variety of stimuli like nutrient deprivation, hypoxia, mitochondrial dysfunction, endoplasmic reticulum stress, and is regulated by immune- and hormonal factors. The role of autophagy in tumor cells is complex. Indeed, autophagy may act as a tumor suppressor as well as a tumor survival factor, in a context-dependent manner. The research into autophagy in normal pituitary and pituitary tumors has not gained great consideration, yet. Nevertheless, some recent articles joint to previous case studies, suggest that this process plays a role in the modulation and fluctuation of normal pituitary cell functions and in the response of pituitary tumor cells to drug therapy, including the response to somatostatin receptor ligand (SRLs), the first-line medical therapy of acromegaly. Although it is not possible to draw any conclusion, the aim of this review was to highlight some considerations and perspectives in this research field. Reports on the effects of octreotide on autophagy induction and autophagic flux in extra-pituitary target tissues, have also been discussed.

The KBTBD6/7-DRD2 axis regulates pituitary adenoma sensitivity to dopamine agonist treatment

Pituitary adenoma (PA) is one of the most common intracranial tumors, and approximately 40% of all PAs are prolactinomas. Dopamine agonists (DAs), such as cabergoline (CAB), have been successfully used in the treatment of prolactinomas. The expression of dopamine type 2 receptor (DRD2) determines the therapeutic effect of DAs, but the molecular mechanisms of DRD2 regulation are not fully understood. In this study, we first demonstrated that DRD2 underwent proteasome-mediated degradation. We further employed the yeast two-hybrid system and identified kelch repeat and BTB (POZ) domain containing 7 (KBTBD7), a substrate adaptor for the CUL3-RING ubiquitin (Ub) ligase complex, as a DRD2-interacting protein. KBTBD6/7 directly interacted with, and ubiquitinated DRD2 at five ubiquitination sites (K221, K226, K241, K251, and K258). CAB, a high-affinity DRD2 agonist, induced DRD2 internalization, and cytoplasmic DRD2 was degraded via ubiquitination under the control of KBTBD6/7, the activity of which attenuated CAB-mediated inhibition of the AKT/mTOR pathway. KBTBD7 knockout (KO) mice were generated using the CRISPR-Cas9 technique, in which the static level of DRD2 protein was elevated in the pituitary gland, thalamus, and heart, compared to that of WT mice. Consistently, the expression of KBTBD6/7 was negatively correlated with that of DRD2 in human pituitary tumors. Moreover, KBTBD7 was highly expressed in dopamine-resistant prolactinomas, but at low levels in dopamine-sensitive prolactinomas. Knockdown of KBTBD6/7 sensitized MMQ cells and primary pituitary tumor cells to CAB treatment. Conversely, KBTBD7 overexpression increased CAB resistance of estrogen-induced in situ rat prolactinoma model. Together, our findings have uncovered the novel mechanism of DRD2 protein degradation and shown that the KBTBD6/7-DRD2 axis regulates PA sensitivity to DA treatment. KBTBD6/7 may thus become a promising therapeutic target for pituitary tumors.

miRNA-182/Deptor/mTOR axis regulates autophagy to reduce intestinal ischaemia/reperfusion injury

It had been reported miR‐182 was down‐regulated after intestinal ischaemia/reperfusion (I/R) damage. However, its role and potential mechanisms are still unknown. This study was aimed to elucidate the function of miR‐182 in intestinal I/R injury and the underlying mechanisms. The model of intestinal injury was constructed in wild‐type and Deptor knockout (KO) mice. Haematoxylin‐eosin staining, Chiu's score and diamine oxidase were utilized to detect intestinal damage. RT‐qPCR assay was used to detected miR‐182 expression. Electronic microscopy was used to detect autophagosome. Western blot was applied to detect the expression of Deptor, S6/pS6, LC3‐II/LC3‐I and p62. Dual‐luciferase reporter assay was used to verify the relationship between miR‐182 and Deptor. The results showed miR‐182 was down‐regulated following intestinal I/R. Up‐regulation of miR‐182 reduced intestinal damage, autophagy, Deptor expression and enhanced mTOR activity following intestinal I/R. Moreover, suppression of autophagy reduced intestinal damage and inhibition of mTOR by rapamycin aggravated intestinal damage following intestinal I/R. Besides, damage of intestine was reduced and mTOR activity was enhanced in Deptor KO mice. In addition, Deptor was the target gene of miR‐182 and was indispensable for the protection of miR‐182 on intestine under I/R condition. Together, our research implicated up‐regulation of miR‐182 inhibited autophagy to alleviate intestinal I/R injury via mTOR by targeting Deptor.