High expression of PPP1CC promotes NHEJ-mediated DNA repair leading to radioresistance and poor prognosis in nasopharyngeal carcinoma.

Protein phosphatase 1 catalytic subunit gamma (PPP1CC) promotes DNA repair and tumor development and progression, however, its underlying mechanisms remain unclear. This study investigated the molecular mechanism of PPP1CC's involvement in DNA repair and the potential clinical implications. High expression of PPP1CC was significantly correlated with radioresistance and poor prognosis in human nasopharyngeal carcinoma (NPC) patients. The mechanistic study revealed that PPP1CC bound to Ku70/Ku80 heterodimers and activated DNA-PKcs by promoting DNA-PK holoenzyme formation, which enhanced nonhomologous end junction (NHEJ) -mediated DNA repair and led to radioresistance. Importantly, BRCA1-BRCA2-containing complex subunit 3 (BRCC3) interacted with PPP1CC to enhance its stability by removing the K48-linked polyubiquitin chain at Lys234 to prevent PPP1CC degradation. Therefore, BRCC3 helped the overexpressed PPP1CC to maintain its high protein level, thereby sustaining the elevation of DNA repair capacity and radioresistance. Our study identified the molecular mechanism by which PPP1CC promotes NHEJ-mediated DNA repair and radioresistance, suggesting that the BRCC3-PPP1CC-Ku70 axis is a potential therapeutic target to improve the efficacy of radiotherapy.

Silencing GMPPB Inhibits the Proliferation and Invasion of GBM via Hippo/MMP3 Pathways.

Glioblastoma multiforme (GBM) is a highly aggressive malignancy and represents the most common brain tumor in adults. To better understand its biology for new and effective therapies, we examined the role of GDP-mannose pyrophosphorylase B (GMPPB), a key unit of the GDP-mannose pyrophosphorylase (GDP-MP) that catalyzes the formation of GDP-mannose. Impaired GMPPB function will reduce the amount of GDP-mannose available for O-mannosylation. Abnormal O-mannosylation of alpha dystroglycan (α-DG) has been reported to be involved in cancer metastasis and arenavirus entry. Here, we found that GMPPB is highly expressed in a panel of GBM cell lines and clinical samples and that expression of GMPPB is positively correlated with the WHO grade of gliomas. Additionally, expression of GMPPB was negatively correlated with the prognosis of GBM patients. We demonstrate that silencing GMPPB inhibits the proliferation, migration, and invasion of GBM cells both in vitro and in vivo and that overexpression of GMPPB exhibits the opposite effects. Consequently, targeting GMPPB in GBM cells results in impaired GBM tumor growth and invasion. Finally, we identify that the Hippo/MMP3 axis is essential for GMPPB-promoted GBM aggressiveness. These findings indicate that GMPPB represents a potential novel target for GBM treatment.

DNTTIP1 promotes nasopharyngeal carcinoma metastasis via recruiting HDAC1 to DUSP2 promoter and activating ERK signaling pathway.

BACKGROUND: Distant metastasis remains the leading cause of treatment failure in patients with nasopharyngeal carcinoma (NPC), making it critical to identify efficient therapeutic targets for metastatic NPC. Previous studies have demonstrated that deoxynucleotidyltransferase terminal-interacting protein 1 (DNTTIP1) is associated with the development of various types of cancer. However, its role and mechanism in NPC have not been explored. METHODS: RNA-seq profiling was performed for three pairs of NPC and normal nasopharynx tissues. DNTTIP1 expression in NPC specimens was detected by immunohistochemistry. In vitro and in vivo assays were used to investigate the function of DNTTIP1. The molecular mechanism was determined using RT-qPCR, western blotting, RNA-seq, luciferase reporter assays, ChIP assays, and co-IP assays. FINDINGS: DNTTIP1 was found to be significantly upregulated in NPC tissues. Furthermore, DNTTIP1 promoted NPC growth and metastasis in vitro and in vivo. Upregulation of DNTTIP1 in NPC indicated poor clinical outcomes. Mechanistically, DNTTIP1 suppressed DUSP2 gene expression via recruiting HDAC1 to its promoter and maintaining a deacetylated state of histone H3K27. The downregulation of DUSP2 resulted in aberrant activation of the ERK signaling and elevated MMP2 levels, promoting NPC metastasis. Chidamide, an HDAC inhibitor, was shown to suppress NPC metastasis by regulating the DNTTIP1/HDAC1-DUSP2 axis. INTERPRETATION: Our findings demonstrate that DNTTIP1 not only regulates NPC metastasis but also independently predicts NPC prognosis. Furthermore, targeting DNTTIP1/HDAC1 by Chidamide may benefit NPC patients with metastasis. FUNDING: This work was supported by the National Natural Science Foundation of China (No. 81872464, 82073243).

Addition of chemoradiotherapy to palliative chemotherapy in de novo metastatic nasopharyngeal carcinoma: a real-world study.

BACKGROUND: To determine whether concurrent chemotherapy is necessary during locoregional radiotherapy (RT) after palliative chemotherapy (PCT) in patients with de novo metastatic nasopharyngeal carcinoma (mNPC). METHODS: A total of 746 patients with mNPC from 2000 to 2017 at our hospital were retrospectively reviewed. Among them, 355 patients received PCT followed by RT. Overall survival (OS) and progression-free survival (PFS), including locoregional progression-free survival (LRPFS) and distant progression-free survival (DPFS) were estimated with the Kaplan-Meier method and log-rank test. Cox proportional-hazards models, landmark analyses, propensity score matching, and subgroup analyses were used to address confounding. RESULTS: Of the patients included in our study, 192 received radiotherapy alone after PCT (PCT + RT), and 163 received concurrent chemoradiotherapy after PCT (PCT + CCRT). The prognosis of PCT + CCRT was significantly better than that of PCT + RT (5 year OS, 53.0 vs 36.2%; P = 0.004). After matching, the 5 year OS rates of the two groups were 55.7 and 39.0%, respectively (P = 0.034) and the median DPFS were 29.4 and 18.7 months, respectively (P = 0.052). Multivariate Cox regression analysis indicated that PCT + CCRT was an independent favorable prognostic factor (P = 0.009). In addition, conducting concurrent chemoradiotherapy after 4-6 cycles of PCT or conducting concurrent chemotherapy with single-agent platinum was associated with significant survival benefit in the matched cohort (5 year OS rate, 60.4 or 57.4%, respectively). The survival difference between groups remained significant when evaluating patients who survived for ≥ 1 year (P = 0.028). CONCLUSIONS: The optimal treatment strategy of mNPC is the combination of PCT followed by concurrent chemoradiotherapy. More specifically, concurrent chemoradiotherapy with single-agent platinum after 4-6 cycles of PCT is suggested.

EBF3 reactivation by inhibiting the EGR1/EZH2/HDAC9 complex promotes metastasis via transcriptionally enhancing vimentin in nasopharyngeal carcinoma.

Metastasis is the major reason for treatment failure and accounts for cancer-related death in patients with nasopharyngeal carcinoma. However, the genetic alterations and molecular mechanisms that cause nasopharyngeal carcinoma metastasis are elusive. Herein, we performed RNA sequencing in patients with or without metastasis, and found that the early B-cell factor 3 (EBF3) was significantly elevated in the samples with metastasis. Mechanistically, EBF3 promoted metastasis by directly combining with the promoter of Vimentin and transcriptionally upregulating it. In addition, EBF3 was epigenetically silenced by EGR1/EZH2/HDAC9 complexes via sustaining the high level of H3K27-Me3 at its promoter. Clinically, there was a positive correlation between EBF3 and Vimentin in nasopharyngeal carcinoma tissues. Moreover, high expression of EBF3 or Vimentin was correlated with poor overall survival, while the combination of high EBF3 and Vimentin expression was associated with more significant poor prognosis. Therefore, specific agents targeting EBF3 or stabilizing the EGR1/EZH2/HDAC9 complex could be novel therapeutic strategies for cancer metastasis.

Treatment and Survival Outcomes Associated With Platinum Plus Low-Dose, Long-term Fluorouracil for Metastatic Nasopharyngeal Carcinoma.

Importance: The treatment of metastatic nasopharyngeal carcinoma (mNPC) is a major challenge because of drug resistance and the toxic effects of chemotherapy. Objective: To evaluate the survival and toxicity outcomes and safety associated with the use of a modified low-dose fluorouracil protocol compared with standard regimens recommended in current guidelines for treatment of mNPC. Design, Setting, and Participants: This retrospective cohort study was based on data retrieved from electronic medical records from Sun Yat-sen University Cancer Center in China for 1397 patients with mNPC diagnosed from January 1, 2006, to December 31, 2017. Data analyses were conducted from October 1, 2020, to May 1, 2021. Exposures: Patients received chemotherapy, including platinum plus low-dose, long-term fluorouracil (PFLL); cisplatin plus standard dose, short-term fluorouracil (PFSS); cisplatin plus gemcitabine (GP); cisplatin plus taxane (TP); and cisplatin plus taxane plus fluorouracil (TPF). Main Outcomes and Measures: The main outcomes included overall survival (OS); subsequent-line, treatment-free survival (sTFS), defined as the period from metastasis to the date requiring subsequent-line treatment or death; and the survival to toxicity ratio (STR), defined as person-year rate of OS divided by person-year rate of severe hematologic toxic effects. Cox regression models were used to compare the outcomes of patients receiving PFLL vs other regimens, adjusting for baseline characteristics. Results: Of 1397 patients with mNPC included in this study (1152 men; median age, 46 years [range, 18-70 years]) 134 received PFLL, 203 received GP, 330 received PFSS, 366 received TP, and 364 received TPF. A total of 764 patients died (75 in treatment group PFLL; 107 in group GP; 204 in group PFSS; 207 in group TP; and 171 in group TPF), and 979 patients had subsequent-line treatment or died, whichever occurred first (PFLL, 77; GP, 144; PFSS, 262; TP, 269; and TPF, 227). The median follow-up was 46.9 months (IQR, 25.4-82.4 months), and the 5-year OS rate among patients who received PFLL was 25.4% (95% CI, 16.7%-38.8%), which was not significantly different from that among patients who did not receive PFLL (30.2%; 95% CI, 27.1%-33.5%; P = .13) or who received GP (25.1%; 95% CI, 18.1%-35.0%; P = .81), PFSS (23.6%; 95% CI, 18.5%-30.0%; P = .80), or TP (28.1%; 95% CI, 22.8%-34.7%; P = .99) but was lower than that for patients who received TPF (40.4%; 95% CI, 34.7%-47.1%; P = .001). The 5-year sTFS among patients who received PFLL (24.1%; 95% CI, 15.4%-37.6%) was significantly higher than that among patients who did not receive PFLL (18.5%; 95% CI, 16.1%-21.3%; P = .005) or who received GP (14.3%; 95% CI, 9.1%-22.5%; P = .001) but similar to that for patients who received TPF (28.0%; 95% CI, 23.0%-34.0%; P = .74). The STR of PFLL was 0.81, substantially better than that of GP (0.41) and TPF (0.65). Conclusions and Relevance: The results of this cohort study suggest that, compared with the use of standard treatment regimens, administration of PFLL was associated with similar OS but prolonged sTFS. PFLL also had better STR than other regimens, which could indicate less severe toxic effects. Thus, PFLL may be an option for first-line treatment of mNPC.

Prognostic role of programmed cell death ligand-1 expression in head and neck cancer treated with programmed cell death protein-1/programmed cell death ligand-1 inhibitors: A meta-analysis based on clinical trials.

PURPOSE: The purpose of our meta-analysis is to clarify whether the biomarker of programmed cell death ligand-1 (PD-L1) could predict the treatment efficacy and prognosis of programmed cell death protein-1 (PD-1)/PD-L1 immune-checkpoint inhibitors (ICIs) in head and neck cancer (HNC) patients. MATERIALS AND METHODS: We performed the article search in four main online databases. The search deadline was September 8, 2020. To elucidate whether a positive or negative PD-L1 expression correlates with different efficacy and prognosis of PD-1/PD-L1-related therapy in HNC, the relative risk (RR) and 95% confidence interval (95% CI) were pooled. Our meta-analysis assigned the overall survival (OS) at 6 and 12 months and the objective response rate (ORR) for the primary end points. RESULTS: The present meta-analysis included 11 relevant studies, which have 1663 HNC cases who received the treatment of PD-1/PD-L1 ICIs. The pooled results revealed that the high or positive expression of PD-L1 predicted better 6- and 12-month OS in head and neck squamous cell carcinoma (HNSCC) (RR 1.30, 95% CI: 1.02-1.65, P = 0.03; and RR 1.31, 95% CI: 1.05-1.62, P = 0.01). PD-L1 expressors were also relevant with higher ORR in HNC patients who had treatment of PD-1/PD-L1 inhibitors compared to PD-L1 nonexpressors (RR 1.84, 95% CI: 1.41-2.41, P < 0.00001). CONCLUSIONS: In summary, PD-L1-positive HNSCC patients portend favorable OS at 6 and 12 months from PD-1/PD-L1 ICIs. Increased ORR also favored to appear in PD-L1 expressors of HNC or recurrent/metastatic HNSCC who received PD-1/PD-L1 ICIs. Therefore, PD-L1 proved to be an appropriate biomarker to predict the clinical efficacy and prognosis of PD-1/PD-L1 ICIs in HNC.

Prognostic value of hepatitis B viral infection in patients with nasopharyngeal carcinoma in the intensity-modulated radiotherapy era.

BACKGROUND: Whether hepatitis B virus (HBV) infection poses risk to patients with nasopharyngeal carcinoma (NPC) in the intensity-modulated radiotherapy (IMRT) era remains unclear. METHODS: 953 patients with non-metastatic, newly diagnosed NPC who received detection of serologic hepatitis B surface antigen (HBsAg) and treated with IMRT were retrospectively reviewed. 171 patients had HBV infection (HBsAg seropositive). Propensity score matching method (PSM) and stabilized inverse probability of treatment weighting (IPTW) were used to address confounding. The survival rates were evaluated by Kaplan-Meier analysis and the survival curves were compared by Log-rank test. Prognostic factors were explored by multivariate analysis. RESULTS: No significant survival differences were observed between HBsAg-negative group and HBsAg-positive group [5-year overall survival (OS), 87.7% vs. 83.9%, P=0.181; locoregional recurrence-free survival (LRFS), 83.5% vs. 78.3%, P=0.109; distant metastasis-free survival (DMFS), 80.2% vs. 77.9%, P=0.446; progression-free survival (PFS), 77.4% vs. 71.4%, P=0.153], consistent with the results of PSM and IPTW analysis. Further analyses revealed that HBV infection was an independent prognostic factor for poor OS [multivariate analysis; hazard ratio (HR), 3.74; 95% confidence interval (CI), 1.45-9.68; P=0.006], LRFS (HR, 2.86; 95% CI, 1.37-5.95); P=0.005] in patients with stage N1, DMFS (HR, 2.65; 95% CI, 1.15-6.09; P=0.022) and PFS (HR, 2.63; 95% CI, 1.34-5.14; P=0.005). Among HBsAg-positive patients, liver protection improved OS (90.3% vs. 77.2%; P=0.022). CONCLUSIONS: HBV infection is an independent risk factor for patients with stage N1 NPC in the IMRT era. Hepatic protection may benefit the survival of HBsAg-positive patients.

The prognostic significance of PD-L1 and PD-1 expression in patients with nasopharyngeal carcinoma: a systematic review and meta-analysis.

BACKGROUND: Whether PD-L1/PD-1 expression plays a significant role in the prognosis of NPC is still controversial. The present study mainly aimed to investigate the prognostic significance of PD-L1/PD-1 expression in patients with NPC. METHODS: A systematical research was performed in the PubMed, Web of Science, EMBASE, and the Cochrane Library databases up to January 06, 2019. Eighteen studies met eligible criteria were included in the meta-analysis. Quality assessment of included articles was evaluated by Newcastle-Ottawa quality assessment scale (NOS). Pooled hazard ratios (HRs) and their corresponding 95% confidence intervals (95% CIs) were used to elucidated the primary endpoint, overall survival (OS), and the secondary endpoints. Furthermore, the relationship between clinicopathological features of NPC and PD-L1/PD-1 expression was estimated by relative ratios (RRs) and 95% CIs. RESULTS: A total of 1836 patients from 15 included studies concerning PD-L1 and 678 patients from six studies regarding PD-1 were included in the meta-analysis. Pooled results revealed that PD-L1 expression in NPC did not correlate with OS (HR 1.34 95% CI 0.93-1.93, p = 0.11), DFS (HR 1.82, 95% CI 0.86-3.85, p = 0.12), PFS (HR 1.19, 95% CI 0.46-3.08, p = 0.72), and DMFS (HR 2.26, 95% CI 0.60-8.56, p = 0.23). Meanwhile, no statistically significant differences existed between the expression level of PD-1 in tumor infiltrating lymphocytes (TILs) and the OS in NPC, with the pooled HR 1.29 (95% CI 0.68-2.42, p = 0.44). In subgroup analysis, higher expression of PD-L1 in immune cells correlated with better OS in patients with NPC, with a pooled HR 0.68 (95% CI 0.47-0.99, p = 0.04). Among the clinicopathological features included in our study, we found that the positive expression of PD-L1 in NPC associated with the higher expression of PD-1 (RR 1.25, 95% CI 1.02-1.52, p = 0.03). CONCLUSIONS: Our meta-analysis indicated that higher/positive expression of PD-L1/PD-1 may not serve as suitable biomarkers for the prognosis of NPC, which was not in consistent with some previous studies about the prognostic value of PD-L1/PD-1 in other types of tumors. Despite the positive results in subgroup analysis and study about clinicopathological features, it may still need corroboration of prospective and large-scale studies.

Liver fluke infection and cholangiocarcinoma: a review.

Parasites are significant groups for carcinogenesis among which liver flukes, including Opisthorchis viverrini and Clonorchis sinensis, are typical representatives causing cholangiocarcinoma (CCA), the second most common primary hepatic malignancy with dismal prognosis. O. viverrini is prevalent in Southeast Asia, infecting 10 million people while C. sinensis has a wider distribution in East Asia and several Southeast Asian countries, affecting more than 35 million people's health. These two worms have some common characteristics and/or discrepancies in life cycle, genome, and transcriptome. As hot spots in recent years, genome and transcriptome research has extracted numerous novel fluke worm-derived proteins, which are excellent for carcinogenic exploration. However, just a handful of these studies have focused on the metabolic pathway. In this study, the main mechanisms of carcinogenesis of both worms, in terms of mechanical damage, metabolic products and immunopathology, and other possible pathways, will be discussed in detail. This review retrospectively describes the main traits of C. sinensis and O. viverrini, their molecular biology and core carcinogenic mechanisms in a contrast pattern.