CYLD downregulates Livin and synergistically improves gemcitabine chemosensitivity and decreases migratory/invasive potential in bladder cancer: the effect is autophagy-associated

KLHL21/CYLD signaling confers aggressiveness in bladder cancer through inactivating NF-κB signaling

Bladder carcinoma (BC) is one of the most commonly diagnosed malignant cancers worldwide. Kelch-like protein 21 (KLHL21) has been shown to be involved in a number of human tumors. The study aimed to investigate the effects and mechanism of KLHL21 on BC progression. We found that KLHL21 expression was significantly decreased in human BC tissues and cell lines compared with the paired normal samples, and patients with lower KLHL21 expression exhibited poorer overall survival. In vitro studies then showed that KLHL21 over-expression significantly reduced the proliferation, migration and invasion in BC cells, while KLHL21 knockdown markedly accelerated the proliferative, migratory and invasive properties of BC cells. Animal studies confirmed that KLHL21 exhibited anti-tumor function in the xenograft mouse models, as indicated by the reduced tumor growth rates, and mice with KLHL21 knockdown showed the opposite tumor growth profile. Additionally, we found that KLHL21 negatively mediated the nuclear factor-κB (NF-κB) signaling activation, as well as its down-streaming molecules involved in the biological regulation of cell survival, death and migratory processes. Mechanistically, cylindromatosis (CYLD) expression levels were significantly up-regulated in BC cells over-expressing KLHL21, but were down-regulated upon KLHL21 knockdown. We further uncovered that KLHL21 directly interacted with CYLD in BC cells. Of note, we found that KLHL21 mainly in cytoplasm could restrain CYLD degradation by prohibiting its ubiquitination in BC cells. More importantly, our in vitro experiments displayed that KLHL21-inhibited progression and NF-κB/p65 activation in BC cells were completely abolished by CYLD deletion, revealing that CYLD expression was required for KLHL21 to perform its anti-tumor function in BC. Collectively, all these findings uncovered that KLHL21/CYLD axis may be a promising therapeutic target for BC treatment.

Targeted Inhibition of O-Linked β-N-Acetylglucosamine Transferase as a Promising Therapeutic Strategy to Restore Chemosensitivity and Attenuate Aggressive Tumor Traits in Chemoresistant Urothelial Carcinoma of the Bladder

Acquisition of acquired chemoresistance during treatment cycles in urothelial carcinoma of the bladder (UCB) is the major cause of death through enhancing the risk of cancer progression and metastasis. Elevated glucose flux through the abnormal upregulation of O-linked β-N-acetylglucosamine (O-GlcNAc) transferase (OGT) controls key signaling and metabolic pathways regulating diverse cancer cell phenotypes. This study showed that OGT expression levels in two human UCB cell models with acquired resistance to gemcitabine and paclitaxel were significantly upregulated compared with those in parental cells. Reducing hyper-O-GlcNAcylation by OGT knockdown (KD) markedly facilitated chemosensitivity to the corresponding chemotherapeutics in both cells, and combination treatment with OGT-KD showed more severe growth defects in chemoresistant sublines. We subsequently verified the suppressive effects of OGT-KD monotherapy on cell migration/invasion in vitro and xenograft tumor growth in vivo in chemoresistant UCB cells. Transcriptome analysis of these cells revealed 97 upregulated genes, which were enriched in multiple oncogenic pathways. Our final choice of suspected OGT glycosylation substrate was VCAN, S1PR3, PDGFRB, and PRKCG, the knockdown of which induced cell growth defects. These findings demonstrate the vital role of dysregulated OGT activity and hyper-O-GlcNAcylation in modulating treatment failure and tumor aggression in chemoresistant UCB.

Molecular and Clinical Characteristics of Primary Pulmonary Lymphoepithelioma-Like Carcinoma

Objectives: Primary pulmonary lymphoepithelioma-like carcinoma (PPLELC) is an extremely rare subtype of non-small cell lung cancer (NSCLC). Currently, there are no established treatment protocols due to rarity of the cancer. Thus, this study aimed to explore the molecular and clinical characteristics of PPLELC.

Study design and setting: Data from patients with PPLELC who were admitted to Zhejiang Cancer Hospital from August 2009 to September 2020 were retrospectively collected. Next-generation sequencing was performed to obtain a genomic profile and tumor mutation burden (TMB) value of patients with adequate tissue and divided them into two groups according to the expression level of PD-L1. The correlation of PD-L1 expression and the clinicopathological characteristics was evaluated by Pearson Chi-square test. Kaplan-Meier curves was applied to present the probability of survival between PD-L1 expression level and overall survival (OS). Moreover, the literature on the immunotherapy of advanced PPLELC published in PubMed between 2016 and 2020 were reviewed and the efficacy of immunotherapy were analyzed.

Results: A total of 18 patients pathologically diagnosed as PPLELC were included. After a follow-up period of 8.8–138 months, 14 patients survived, three patients died and one patient lost, the median OS was 45.3 months Seven samples (tissue-available) tested by NGS and the median TMB was 2.5 mutations/Mb. 19 somatic mutated genes were recognized and TP53 (43%) and CYLD (43%) were the two most commonly mutated genes. Only seven patients who underwent NGS were tested for PD-L1. Three patients with high PD-L1 expression (PD-L1≥ 50%) and four patients with low PD-L1 expression (PD-L1 <50%) were included. No significant correlation was observed between PD-L1 expression and clinical characteristics (age, gender, smoking status, tumor stage, lymph node metastasis) (p > 0.05) and OS (p = 1). What’s more, 10 PPLELC patients involved in previous studies and one patient received nivolumab in the current study were collected retrospectively. 4/11 (36.4%) patients achieved PR, 6/11 (54.5%) patients achieved SD, and 1/11 (9.1%) patients achieved PD and the disease control rate (DCR) was 90.9%.

Conclusions: The prognosis of PPLELC is better than that of other NSCLC, and immunotherapy may be a promising treatment to prolong the survival of advanced PPLELC patients. Whether the immunotherapy efficacy of PPLELC can be predicted by PD-L1 and TMB needs further clinical investigation. CYLD genetic alterations may participate in Epstein–Barr virus-mediated tumorigenesis in PPLELC, providing a novel therapeutic target.

Knockdown of microRNA-130b improves doxorubicin sensitivity in bladder urothelial carcinoma by negatively regulating cylindromatosis expression

INTRODUCTION

Chemotherapeutic resistance reduces the sensitivity of bladder urothelial carcinoma (BUC) to chemotherapeutic drugs and contributes a barrier leading to treatment failure. The purpose of this research project is to investigate the regulatory effects of miR-130b on chemotherapeutic drug resistance of BUC and its mechanism.

MATERIAL AND METHODS

The relative expression of miRNA-130b and cylindromatosis (CYLD) was examined using real-time quantitative PCR. The cell proliferation and doxorubicin sensitivity were detected with the enhanced CCK-8 assay. The specific combination of miR-130b and CYLD was verified with the luciferase reporter gene assay. Protein expression was detected by Western blot.

RESULTS

Our study found that miR-130b was up-regulated in doxorubicin-insensitive BUC tissues and cell lines, and its high expression was negatively related to doxorubicin sensitivity in BUC. The miR-130b knockdown reduced the IC₅₀ of doxorubicin and improved doxorubicin sensitivity of J82/Dox and T24/Dox cells. For the regulation mechanism analysis of miR-130b, bioinformatics analysis software was used to predict the potential targets of miR-130b, including the CYLD gene. The following luciferase activities assay, quantitative real time-PCR and western blot identified the CYLD gene as a target of miR-130b. Knockdown of CYLD reversed miR-130b's regulatory roles in doxorubicin sensitivity in J82/Dox and T24/Dox cells.

CONCLUSIONS

High expression of miR-130b is negatively related to doxorubicin sensitivity in BUC, and knockdown of miR-130b improves doxorubicin sensitivity in BUC by negatively regulating CYLD expression. Our findings will provide guidance for the clinical chemotherapy of BUC.

CYLD Alterations in the Tumorigenesis and Progression of Human Papillomavirus-Associated Head and Neck Cancers

Genetic alterations of CYLD lysine 63 deubiquitinase (CYLD), a tumor-suppressor gene encoding a deubiquitinase (DUB) enzyme, are associated with the formation of tumors in CYLD cutaneous syndrome. Genome sequencing efforts have revealed somatic CYLD alterations in multiple human cancers. Moreover, in cancers commonly associated with human papillomavirus (HPV) infection (e.g., head and neck squamous cell carcinoma), CYLD alterations are preferentially observed in the HPV-positive versus HPV-negative form of the disease. The CYLD enzyme cleaves K63-linked polyubiquitin from substrate proteins, resulting in the disassembly of key protein complexes and the inactivation of growth-promoting signaling pathways, including pathways mediated by NF-κB, Wnt/β-catenin, and c-Jun N-terminal kinases. Loss-of-function CYLD alterations lead to aberrant activation of these signaling pathways, promoting tumorigenesis and malignant transformation. This review summarizes the association and potential role of CYLD somatic mutations in HPV-positive cancers, with particular emphasis on the role of these alterations in tumorigenesis, invasion, and metastasis. Potential therapeutic strategies for patients whose tumors harbor CYLD alterations are also discussed. IMPLICATIONS: Alterations in CYLD gene are associated with HPV-associated cancers, contribute to NF-κB activation, and are implicated in invasion and metastasis.

Inhibition of autophagy by chloroquine enhances the antitumor activity of gemcitabine for gallbladder cancer

Gemcitabine (GEM), as an anti-metabolic nucleoside analog, has been shown to have anticancer effects in various tumors, but its chemotherapy resistance is still an important factor leading to poor prognosis of cancer patient. A large number of studies in recent years have shown that autophagy plays an important role in the chemotherapy sensitivity of many tumors, including pancreatic, non-small cell lung, and bladder cancer. However, whether GEM causes autophagy in gallbladder cancer (GBC) and whether it is related to chemotherapy resistance is unknown. In the present study, we demonstrated that GEM induced apoptosis and protective autophagy in GBC cells, which may be related to the AKT/mTOR signaling pathway, and GEM in combination with autophagy inhibitor chloroquine can strengthen the cytotoxic effect of GEM on GBC in vitro and in vivo. These findings showed that both autophagy and AKT/mTOR signals were engaged in GBC cell death evoked by GEM, GBC patients might benefit from this new treatment strategy, and molecular targeted treatment in combination with autophagy inhibitors shows promise as a treatment improvement.

Valosin-containing protein promotes metastasis of osteosarcoma through autophagy induction and anoikis inhibition via the ERK/NF-κβ/beclin-1 signaling pathway

Valosin-containing protein (VCP) promotes the development of metastasis in osteosarcoma (OS) via the PI3K/Akt signaling pathway. However, inhibition of the PI3K/Akt pathway does not completely reverse VCP-mediated invasion and migration of OS, suggesting that VCP-mediated OS invasion and migration involves additional mechanisms. In the present study, a positive correlation between the expression of VCP and cell autophagy was observed among OS tissues. Inhibiting VCP may decrease the survival of malignant cells; however, an autophagy stimulator may compensate for VCP inhibition and promote malignant cell survival. Altering the level of autophagy did not affect cell invasiveness or migration. ERK, NF-κβ and beclin-1 protein expression levels were markedly decreased following VCP inhibition. These findings indicated that VCP may induce autophagy and enhance anoikis resistance without affecting cell invasiveness or migration. Via anoikis resistance, VCP may promote metastasis in OS. Therefore, targeting of the ERK/NF-κβ/beclin-1 signaling pathway may be an effective therapeutic strategy for the management of OS.

LncRNA CCAT1 inhibits cell apoptosis of renal cell carcinoma through up-regulation of Livin protein

This study was to investigate the involvement of long non-coding RNA (lncRNA) colon cancer-associated transcript-1 (CCAT1) in renal cell carcinoma (RCC) and to further uncover its underlying mechanism. In this study, the expression of CCAT1 and Livin of RCC tissues or cells was determined using qRT-PCR (quantitative real-time PCR) and western blot, respectively. RNA pulldown and RIP (RNA-Binding Protein Immunoprecipitation) assays were performed to examine the sequence interaction between CCAT1 and Livin. The viability and apoptosis of RCC cells was assessed by MTT(3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and TUNEL (TdT-mediated dUTP nick end labeling) assays, respectively. Mice of tumor animal models were established to observe the effect of CCAT1 on RCC tumor growth. The relative expression of CCAT1 in RCC tissues and cell lines was obviously higher than that of the control. CCAT1 knockdown could reduce cell viability and increase the apoptosis of RCC cells in vitro. Furthermore, Livin was significantly inhibited by CCAT1 silencing; RNA pulldown and RIP assays showed that CCAT1 was physically associated with Livin protein. Moreover, Livin overexpression not only significantly inhibited RCC cell apoptosis and increased cell viability, but completely reversed the si-CCAT1-mediated repression of cell viability. More importantly, CCAT1 silencing could inhibit the growth of RCC in vivo that was accompanied by the reduction of Livin in RCC tissues. CCAT1 inhibits RCC cell apoptosis and increases cell viability through up-regulation of Livin.

Livin enhances chemoresistance in head and neck squamous cell carcinoma

The responsiveness of head and neck squamous cell carcinoma (HNSCC) to chemotherapy widely affects prognosis. Overcoming chemoresistance is necessary to improve prognoses in patients with advanced HNSCC. Evasion of apoptosis by cancer cells is a major cause of chemoresistance. Livin, a member of the human inhibitors of apoptosis protein family, is highly expressed in various human cancer tissues and is associated with tumor progression and poor prognosis in human cancers. The aim of the present study was to evaluate the role of Livin in the susceptibility to popularly used chemotherapeutic drugs such as cisplatin, 5-fluorouracil (FU) and docetaxel in human HNSCC cell lines (SNU1041, PCI1 and PCI50 cells). Reverse transcription polymerase chain reaction and western blotting were performed to determine mRNA and protein expression levels. Cell viability and apoptosis assays were used to assess the functional effects of small-interfering RNA-mediated knockdown of Livin. Each HNSCC cell line had different sensitivity to chemotherapeutic drugs. Livin knockdown significantly enhanced cytotoxicity to cisplatin, 5-FU and docetaxel in human HNSCC cells. Livin knockdown induced apoptosis and enhanced chemotherapy-induced apoptosis to cisplatin, 5-FU and docetaxel. Consistent with this, Livin-knockdown cells showed greater expression of cleaved caspases-3 and -7 and poly(ADP-ribose)polymerase compared with that in control cells after cisplatin, 5-FU, or docetaxel treatment. In conclusion, our results suggest that siRNA-mediated Livin knockdown enhanced the chemosensitivity of the three HNSCC cell lines to cisplatin, 5-FU and docetaxel. Although further investigations are required to support these findings, our results demonstrated that novel therapeutic strategies with combined use of siRNA targeting Livin and chemotherapeutic agents may have applications in the treatment of advanced HNSCC.