REGγ deficiency suppresses tumor progression via stabilizing CK1ε in renal cell carcinoma

New horizons in the mechanisms and therapeutic strategies for PD-L1 protein degradation in cancer

Programmed death-ligand 1 (PD-L1) has become a crucial focus in cancer immunotherapy considering it is found in many different cells. Cancer cells enhance the suppressive impact of programmed death receptor 1 (PD-1) through elevating PD-L1 expression, which allows them to escape immune detection. Although there have been significant improvements, the effectiveness of anti-PD-1/PD-L1 treatment is still limited to a specific group of patients. An important advancement in cancer immunotherapy involves improving the PD-L1 protein degradation. This review thoroughly examined the processes by which PD-L1 breaks down, including the intracellular pathways of ubiquitination-proteasome and autophagy-lysosome. In addition, the analysis revealed changes that affect PD-L1 stability, such as phosphorylation and glycosylation. The significant consequences of these procedures on cancer immunotherapy and their potential role in innovative therapeutic approaches are emphasised. Our future efforts will focus on understanding new ways in which PD-L1 degradation is controlled and developing innovative treatments, such as proteolysis-targeting chimeras designed specifically to degrade PD-L1. It is crucial to have a thorough comprehension of these pathways in order to improve cancer immunotherapy strategies and hopefully improve therapeutic effectiveness.

FOXK1 upregulation is correlated with tumor progression and tumor associated macrophages infiltration in renal cell carcinoma

Renal cell carcinoma (RCC) is one of the most common urological cancers in adults. Forkhead box k1 (FOXK1) is a transcription factor involved in the progression of various malignant tumors. In this study, we aimed to investigate the expression and roles of FOXK1 in RCC development. Our findings revealed increased expression of FOXK1 in RCC tumor tissues and cell lines compared with normal controls. Functional assays demonstrated that knockdown of FOXK1 significantly inhibited proliferation, migration, invasion, and promoted apoptosis in RCC cells. Furthermore, FOXK1 knockdown suppressed epithelial-mesenchymal transition and Wnt signaling in RCC cells. Additionally, we observed a correlation between FOXK1 upregulation and tumor associated macrophages infiltration in RCC. These results suggest that FOXK1 acts as an oncogene in RCC and may serve as a potential therapeutic target for RCC treatment.

Berberine inhibits the progression of renal cell carcinoma cells by regulating reactive oxygen species generation and inducing DNA damage

BACKGROUND

Berberine is a natural isoquinoline alkaloid that has been shown to have antitumor properties in a growing number of studies. However, its role in renal cell carcinoma remains unclear. This study investigates berberine's effect and mechanism in renal cell carcinoma.

METHODS

The methyl-tetrazolium, colony formation, and lactate dehydrogenase assay were used to detect proliferation and cytotoxicity, respectively. Flow cytometry, caspase-Glo 3/7 assay, and adenosine triphosphate assay were used to detect apoptosis and the adenosine triphosphate levels. Wound healing and transwell assay were used to examine the migration ability of renal cell carcinoma cells. Besides, the level of reactive oxygen species (ROS) was explored using a DCFH-DA-based kit. Additionally, western blot and Immunofluorescence assay was taken to determine the levels of relative proteins.

RESULTS

In vitro, our findings indicated that the proliferation and migration of renal cell carcinoma cells treated with berberine in various concentrations were inhibited, while the level of ROS and apoptosis rate were increased. Furthermore, The results of western blot showed that the expression of Bax, Bad, Bak, Cyto c, Clv-Caspase 3, Clv-Caspase 9, E-cadherin, TIMP-1and γH2AX were up-regulated, while Bcl-2, N-cadherin, Vimentin, Snail, Rad51 and PCNA were down-regulated after treating with berberine with various concentration.

CONCLUSION

The result of this study revealed that berberine inhibits renal cell carcinoma progression via regulating ROS generation and inducing DNA break.

The critical role of the Hippo signaling pathway in kidney diseases

The Hippo signaling pathway is involved in cell growth, proliferation, and apoptosis, and it plays a key role in regulating organ size, tissue regeneration, and tumor development. The Hippo signaling pathway also participates in the occurrence and development of various human diseases. Recently, many studies have shown that the Hippo pathway is closely related to renal diseases, including renal cancer, cystic kidney disease, diabetic nephropathy, and renal fibrosis, and it promotes the transformation of acute kidney disease to chronic kidney disease (CKD). The present paper summarizes and analyzes the research status of the Hippo signaling pathway in different kidney diseases, and it also summarizes the expression of Hippo signaling pathway components in pathological tissues of kidney diseases. In addition, the present paper discusses the positive therapeutic significance of traditional Chinese medicine (TCM) in regulating the Hippo signaling pathway for treating kidney diseases. This article introduces new targets and ideas for drug development, clinical diagnosis, and treatment of kidney diseases.

Zinc finger Asp-His-His-Cys palmitoyl -acyltransferase 19 accelerates tumor progression through wnt/β-catenin pathway and is upregulated by miR-940 in osteosarcoma

Osteosarcoma (OS) is the most frequent malignant primary bone tumor in children and young adults. Zinc finger Asp-His-His-Cys palmitoyl-acyltransferase 19 (ZDHHC19) is a key enzyme in protein palmitoylation and plays crucial roles in tumor progression. However, its expression profile and biological function in OS have been unclear. In the present study, the expression level of ZDHHC19 in OS cell lines was determined by qRT-PCR and Western blot. The effect of ZDHHC19 in cell growth, invasion and migration was analyzed by CCK8, EDU, transwell, wound healing assay in vitro, and xenograft tumor model in vivo. In addition, bioinformatics analysis was used to explore the potential mechanism of ZDHHC19 in OS. Furthermore, the luciferase reporter assay was conducted to determine the direct binding between miR-940 and ZDHHC19. We discovered that ZDHHC19 was overexpressed in OS cells compared with the normal cells. The functional investigation demonstrated that ZDHHC19 silencing could inhibit proliferation, invasion and migration of OS in vitro and suppress tumorigenicity and lung metastasis in a xenograft model in vivo. Mechanistically, we identified that ZDHHC19 was a direct target of miR-940 and forced ZDHHC19 expressions partially rescue the suppression of proliferation, migration and invasion induced by miR-940. Moreover, bioinformatics analysis combined with validation experiments revealed that activating wnt/β-catenin pathway contributed to the pro-oncogenic effect induced by ZDHHC19. Furthermore, rescue experiments further verified that miR-940/ZDHHC19 axis regulated wnt/β-catenin pathway. Overall, these findings indicated that miR-940/ZDHHC19 axis played a significant role in OS progression and might be considered as a novel target for OS treatment.Abbreviations: OS, osteosarcoma; miRNAs, microRNAs; 3'-UTR, 3'- untranslated region; TARGET, Therapeutically Applicable Research To Generate Effective Treatments; qRT-PCR, quantitative real-time PCR; IHC, Immunohistochemistry; GSVA, Gene Set Variation Analysis; GSEA, Gene Set Enrichment Analysis; KEGG, Kyoto Encyclopedia of Genes and Genomes.

REGγ regulates circadian clock by modulating BMAL1 protein stability

Endogenous clocks generate rhythms in gene expression, which facilitates the organisms to cope through periodic environmental variations in accordance with 24-h light/dark time. A core question that needs to be elucidated is how such rhythms proliferate throughout the cells and regulate the dynamic physiology. In this study, we demonstrate the role of REGγ as a new regulator of circadian clock in mice, primary MEF, and SY5Y cells. Assessment of circadian conduct reveals a difference in circadian period, wheel mode, and the ability to acclimate the external light stimulus between WT and KO littermates. Compared to WT mice, REGγ KO mice attain the phase delay behavior upon light shock at early night. During the variation of 12/12 h light/dark (LD) exposure, levels of Per1, Per2, Cry1, Clock, Bmal1, and Rorα circadian genes in suprachiasmatic nucleus are significantly higher in REGγ KO than in WT mice, concomitant with remarkable changes in BMAL1 and PER2 proteins. In cultured cells depleted of REGγ, serum shock induces early response of the circadian genes Per1 and Per2 with the cyclic rhythm maintained. Mechanistic study indicates that REGγ directly degrades BMAL1 by the non-canonical proteasome pathway independent of ATP and ubiquitin. Silencing BMAL1 abrogates the changes in circadian genes in REGγ-deficient cells. However, inhibition of GSK-3β, a known promoter for degradation of BMAL1, exacerbates the action of REGγ depletion. In conclusion, our findings define REGγ as a new factor, which functions as a rheostat of circadian rhythms to mitigate the levels of Per1 and Per2 via proteasome-dependent degradation of BMAL1.

Role of oncogenic REGγ in cancer

Cancer is a critical global health-care problem with limited therapeutic options. Since cancers are life-threatening illnesses, the identification of a promising oncotarget and its clinical correlates are relevant. Mounting evidence has emerged indicating that REG gamma (REGγ), a member of the 11S proteasome activators, plays a pivotal role in the development of multiple human cancers. However, an elaborate summary on the association between REGγ and cancer is still lacking. In this Review, we discuss how REGγ, through its ATP- and ubiquitin-independent manners, represents a promising cancer biomarker and therapeutic oncotarget for multiple human cancers. Aberrant REGγ expression closely associated with tumorigenesis attributes to its biological functions for controlling and regulating cell cycle, proliferation, migration, invasion, angiogenesis, and metastasis of the cancer cells by degrading proteins of cytosol and nucleus in the eukaryotic cells. REGγ serves as a molecular switch to activate multifarious oncogenic signaling pathways, such as MAPK/p38, TGF-β/Smad, and Wnt/β-catenin. The review describes that targeting REGγ may provide new diagnostic and therapeutic applications in cancer.

REG γ knockdown suppresses proliferation by inducing apoptosis and cell cycle arrest in osteosarcoma

Background

Osteosarcoma (OS) is the most common malignant bone tumor with high mortality in children and adolescents. REG γ is overexpressed and plays oncogenic roles in various types of human cancers. However, the expression and potential roles of REG γ in osteosarcoma are elusive. This study aims at exploring possible biological functions of REG γ in the pathogenesis of osteosarcoma and its underlying mechanism.

Methods

Quantitativereverse transcription-polymerase chain reaction (qRT-PCR), western blotting andimmunohistochemistry (IHC)were performed to detect the expression levels of REG γ in OS tissues and cell lines. Then, the effects of REG γ expression on OS cell proliferation in vitro were analyzed by Cell Counting Kit-8 (CCK-8), ethylene deoxyuridine (EdU), colony formation, flow cytometry. The protein levels of apoptosis and cell-cycle related proteins were evaluated using western blotting.

Results

In present study, we found for the first time that REG γ is overexpressed in osteosarcoma tissues and cell lines and knockdown of REG γ significantly inhibits cell proliferation and induces apoptosis and cell cycle arrest in osteosarcoma cells. Furthermore, we observed that p21, caspase-3 and cleaved caspase-3 are increased while the expression of cycinD1 and bcl-2 are decreased after REG γ depletion in osteosarcoma cells. In conclusion, REG γ may be involved in the proliferation of osteosarcoma and serve as a novel therapeutic target in patients with osteosarcoma.

The oncogenic role of REG γ is exerted by activating the Wnt/β-catenin signaling pathway in osteosarcoma

BACKGROUND

Proteasome activator γ (REG γ) expression was found to be upregulated and to play critical roles in several cancers. However, the effect of REG γ on osteosarcoma (OS) remains unclear. The objective of the present study was to explore the clinical significance of REG γ and its function in regulating the progression of OS.

METHODS

Quantitative reverse transcription-polymerase chain reaction (qRT-PCR), western blotting (WB) and immunohistochemistry (IHC) analyses were performed to detect the expression levels of REG γ in OS tissues and cell lines. Then, the effects of REG γ expression on OS cell behavior in vitro were analyzed by Cell Counting Kit-8 (CCK-8), ethylene deoxyuridine (EdU), colony formation, flow cytometry, wound healing and transwell assays. The protein and mRNA levels of components involved in the Wnt/β-catenin pathway were evaluated using WB and qRT-PCR, respectively.

RESULTS

We found that REG γ expression was significantly upregulated in both OS tissues and cell lines. Our in vitro assay results confirmed that knockdown of REG γ inhibited cell proliferation, migration, and invasion and induced apoptosis and cell cycle arrest in OS. Additionally, through WB and qRT-PCR analyses, we found that REG γ depletion markedly decreased the β-catenin, cyclin D1 and c-myc expression levels and increased the GSK-3β expression levels in OS cell lines.

CONCLUSIONS

Our results revealed that REG γ plays an oncogenic role in OS by activating the Wnt/β-catenin pathway, indicating that REG γ may be a promising therapeutic target for OS patients.

[Construction of an oral squamous cell carcinoma cell line for stable PA28γ overexpression]

OBJECTIVE

To construct a PA28γ overexpression cell line and determine its effects after infecting an oral squa-mous cell carcinoma (OSCC) cell line.

METHODS

The PA28γ gene was cloned into the pLOV.CMV.cherry.2A.EF1a.PuroR lentiviral vector by polymerase chain reaction (PCR), and PCR and DNA sequencing alignment analysis were used for identification. Then, 293T cells were used to package viral diseases. Infected OSCC cells were used to construct a cell line with stable PA28γ overexpression. Finally, the level of PA28γ expression in the OSCC cell line was detected through Western blot.

RESULTS

The successful construction of PA28γ recombinant lentiviral vectors was confirmed by DNA sequencing. The results of immunofluorescence showed that the PA28γ overexpression lentivirus successfully infected the OSCC cells and showed cherry red fluorescence. The results of Western blot demonstrated that the constructed cells with stable PA28γ overexpression significantly increased the expression of PA28γ.

CONCLUSIONS

The PA28γ overexpression lentiviral vector can significantly increase its protein expression in OSCC cells. We provide a stable OSCC cell line for further study on the effect of PA28γ in OSCC.

Silencing PSME3 induces colorectal cancer radiosensitivity by downregulating the expression of cyclin B1 and CKD1

Resistance to radiotherapy remains a severe obstacle in the treatment of high-risk colorectal cancer patients. Recent studies have indicated that proteasome activator complex subunit 3 (PSME3) participates in the development and progression of various human malignancies and is proposed to play a role in tumor radioresistance. However, the impact of PSME3 on radioresistance of colorectal cancer has been largely unknown. In the present study, the enhanced expression of PSME3 was observed in colorectal cancer cells and tissue. Upregulation of PSME3 was significantly implicated in lymph node state, lymphovascular invasion, and Dukes' stage. Furthermore, high PSME3 expression was closely linked to poorer overall and progression-free survival in patients with colorectal cancer. The study further demonstrated that the proliferative, invasive and migratory potential of colorectal cancer cells was effectively inhibited in vitro after silencing PSME3. Our results verified that knockdown of PSME3 probably triggered cell cycle arrest at the G2/M phase by downregulation of cyclinB1 and CDK1, thereby enhancing the radiosensitivity of colorectal cancer cells. These data illustrated that PSME3 is a promising biomarker predictive of colorectal cancer prognosis and silencing of PSME3 may provide with a new approach for sensitizing the radiotherapy in colorectal cancer.

Impact statement

It is reported that colorectal cancer (CRC) is the third most common cancer worldwide and the fourth leading cause of cancer-related death. At present, the main treatment method of colorectal cancer is surgery, supplemented by radiotherapy and chemotherapy. Among them, radiotherapy plays an important role in the treatment of locally advanced colorectal cancer, surgery, and chemotherapy. Our study found that down-regulation of PSME3 may enhance the radiosensitivity of CRC cells by triggering cell cycle arrest, which suggests that silence PSME3 may provide a new method for improving the radiosensitivity of CRC. What’more, our research also demonstrated that PSME3 may promote proliferation, invasive and migratory potential of CRC cells, which implies that PSME3 might be a biomarker of CRC for early diagnosis and treatment.

HNF‑4α downregulation promotes tumor migration and invasion by regulating E‑cadherin in renal cell carcinoma

Renal cell carcinoma (RCC) is the most common malignant disease of the kidneys in adults. Patients with metastatic RCC have an unusually poor prognosis and exhibit resistance to all current therapies. Therefore, it is necessary to explore novel molecules involved in the progression of RCC and to identify effective therapeutic targets. Hepatocyte nuclear factor-4α (HNF-4α) serves an important role in hepatocyte differentiation and is involved in the progression of liver cancer; however, the functional role of HNF-4α has not been well established in RCC. The present study reported that HNF-4α expression was markedly downregulated in RCC tissue samples compared with in normal controls by immunohistochemistry and RNA-sequencing analysis. Statistical analysis demonstrated that HNF-4α downregulation was significantly associated with tumor stage, recurrence, metastasis and poor prognosis in patients with RCC. Furthermore, wound-healing and Transwell assays revealed that downregulation of HNF-4α promoted cell migration and invasion by transcriptionally regulating E-cadherin in RCC. Finally, a positive correlation was revealed between HNF-4α expression and E-cadherin expression, and patients with low E-cadherin expression also had a poor prognosis. These findings may provide novel insights into the biological effects of HNF-4α and lay the foundation for the discovery of molecular therapeutic targets in RCC.

A positive feed-forward loop between LncRNA-URRCC and EGFL7/P-AKT/FOXO3 signaling promotes proliferation and metastasis of clear cell renal cell carcinoma

Background

The aberrant expression of long noncoding RNAs (lncRNAs) has recently emerged as key molecules in human cancers; however, whether lncRNAs are implicated in the progression of clear cell renal cell carcinoma (ccRCC) remains unclear.

Methods

Candidate lncRNAs were selected using microarray analysis and quantitative real-time PCR (qRT-PCR) was performed to detect lncRNAs expression in human ccRCC tissues. Overexpression and knocking down experiments in vivo and in vitro were performed to uncover the biological roles of lncRNA-URRCC on ccRCC cell proliferation and invasion. Microarray, chromatin immunoprecipitation, Luciferase reporter assay and western blot were constructed to investigate the molecular mechanisms underlying the functions of lncRNA-URRCC.

Results

The microarray analysis and qRT-PCR identified a new lncRNA, URRCC, whose expression is upregulated in RCC samples and associated with poor prognosis, leading to promote ccRCC cell proliferation and invasion. Mechanistically, URRCC enhances the expression of EGFL7 via mediating histone H3 acetylation of EGFL7 promoter, activation of P-AKT signaling, and suppressing P-AKT downstream gene, FOXO3. In return, FOXO3 could inhibit the transcription of URRCC via binding to the special region on the promoter of URRCC.

Conclusions

Our data suggests that targeting this newly identified feed-back loop between LncRNA-URRCC and EGFL7/P-AKT/FOXO3 signaling may enhance the efficacy of existing therapy and potentially imparts a new avenue to develop more potent therapeutic approaches to suppress RCC progression.

Electronic supplementary material

The online version of this article (10.1186/s12943-019-0998-y) contains supplementary material, which is available to authorized users.

RNA-binding protein QKI regulates contact inhibition via Yes-associate protein in ccRCC

Contact inhibition adjusts organ size to the proper size and ensures the cultured cells growing to a monolayer. By regulating the downstream coordinator YAP, the evolutionarily conserved Hippo transduction pathway attunes cell growth and death in response to cell contact inhibition, polarity, self-renewal, and differentiation. Dysregulation of this pathway is involved in various diseases such as cancer. RNA-binding protein QKI regulates cell proliferation, metabolism, division, and immunity in various cancer models, but its role in cancer cell contact inhibition remains unclear. In this study, we aimed to clarify the relationship between QKI and YAP, and the role of their interaction in cell contact inhibition. We found a lower QKI expression level in sparse condition, whereas a higher expression level in confluent condition by western blot analysis and immunofluorescence assay. QKI knockdown elevated cell proliferation and invasion both in vitro and in vivo. Strikingly, the results of CCK-8 assay, colony formation assay, and transwell assay showed that the phenomenon was in accord with the expression level of pYAP and reverse with YAP. Higher levels of Wnt3a and β-catenin were also found in xenografts of QKI-knockdown clear cell renal cell carcinoma (ccRCC) CAKI-1 cells by western blot analysis and immumohistochemical staining. Finally, a positive correlation between QKI and pYAP was found in clinical specimens by immunohistochemistry. Thus, as a negative regulator of YAP, QKI attuned the cell contact inhibition, leading to inhibition of cancer cell proliferation and invasion through Wnt and GPCR pathway.