Identification of active natural products that induce lysosomal biogenesis by lysosome-based screening and biological evaluation.

Lysosomal biogenesis is an essential adaptive process by which lysosomes exert their function in maintaining cellular homeostasis. Defects in lysosomal enzymes and functions lead to lysosome-related diseases, including lysosomal storage diseases and neurodegenerative disorders. Thus, activation of the autophagy-lysosomal pathway, especially induction of lysosomal biogenesis, might be an effective strategy for the treatment of lysosome-related diseases. In this study, we established a lysosome-based screening system to identify active compounds from natural products that could promote lysosomal biogenesis. The subcellular localizations of master transcriptional regulators of lysosomal genes, TFEB, TFE3 and ZKSCAN3 were examined to reveal the potential mechanisms. More than 200 compounds were screened, and we found that Hdj-23, a triterpene isolated from Walsura cochinchinensis, induced lysosomal biogenesis via activation of TFEB/TFE3. In summary, this study introduced a lysosome-based live cell screening strategy to identify bioactive compounds that promote lysosomal biogenesis, which would provide potential candidate enhancers of lysosomal biogenesis and novel insight for treating lysosome-related diseases.

Identification of limonoids from Walsura yunnanensis and evaluation of their cytotoxicity against cancer cell lines.

Three new limonoids, walsurauias A-C (1-3), along with four known ones, were isolated from the leaves and twigs of Walsura yunnanensis C. Y. Wu. Their structures were determined on the basis of comprehensive spectroscopic data analysis. The new limonoids were screened for their cytotoxic activity (IC50 0.81-5.73 µM) against four human cancer cell lines, including A549, HepG2, HCT116 p21KO and CNE-2. And α,ß-unsaturated ketone moieties in rings A and B are essential for their cytotoxic activity. Selected compounds were further investigated. Compounds 1-3 effectively induced G2/M cell cycle arrest and apoptosis in a dose-dependent manner in cancer cells. In addition, compounds 1-3 inhibited the colony formation and compounds 2 and 3 suppressed the migration of cancer cells.

Tagitinin C induces ferroptosis through PERK-Nrf2-HO-1 signaling pathway in colorectal cancer cells.

Rationale: Colorectal cancer (CRC) is a common malignant tumor of the digestive system. However, the efficacy of surgery and chemotherapy is limited. Ferroptosis is an iron- and reactive oxygen species (ROS)-dependent form of regulated cell death (RCD) and plays a vital role in tumor suppression. Ferroptosis inducing agents have been studied extensively as a novel promising way to fight against therapy resistant cancers. The aim of this study is to investigate the mechanism of action of tagitinin C (TC), a natural product, as a novel ferroptosis inducer in tumor suppression. Methods: The response of CRC cells to tagitinin C was assessed by cell viability assay, clonogenic assay, transwell migration assay, cell cycle assay and apoptosis assay. Molecular approaches including Western blot, RNA sequencing, quantitative real-time PCR and immunofluorescence were employed as well. Results: Tagitinin C, a sesquiterpene lactone isolated from Tithonia diversifolia, inhibits the growth of colorectal cancer cells including HCT116 cells, and induced an oxidative cellular microenvironment resulting in ferroptosis of HCT116 cells. Tagitinin C-induced ferroptosis was accompanied with the attenuation of glutathione (GSH) levels and increased in lipid peroxidation. Mechanistically, tagitinin C induced endoplasmic reticulum (ER) stress and oxidative stress, thus activating nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2). As a downstream gene (effector) of Nrf2, heme oxygenase-1 (HO-1) expression increased significantly with the treatment of tagitinin C. Upregulated HO-1 led to the increase in the labile iron pool, which promoted lipid peroxidation, meanwhile tagitinin C showed synergistic anti-tumor effect together with erastin. Conclusion: In summary, we provided the evidence that tagitinin C induces ferroptosis in colorectal cancer cells and has synergistic effect together with erastin. Mechanistically, tagitinin C induces ferroptosis through ER stress-mediated activation of PERK-Nrf2-HO-1 signaling pathway. Tagitinin C, identified as a novel ferroptosis inducer, may be effective chemosensitizer that can expand the efficacy and range of chemotherapeutic agents.

The molecular basis for p53 inhibition of autophagy in porcine fibroblast cells.

BACKGROUND: Autophagy regulation involves an intricate network that can degrade and recycle cytosolic components in autophagosomes when cells are subject to various stress signals. p53 plays a dual role of induction or inhibition in the regulation of autophagy. Recently, pigs have been considered an excellent large animal model for their many anatomical and physiological similarities to humans. Here, we investigated the relationship between p53 and autophagy, as well as the underling molecular basis, in porcine fibroblast cells (PFCs). METHODS: Autophagy was induced by Earle's balanced salt solution (EBSS) in p53-/- and p53wt PFCs. The autophagy response was assessed by immunoblotting, transmission electron microscopy (TEM) and fluorescent staining. The molecular basis for p53 regulation of autophagy was analyzed by qPCR. RESULTS: We found that the increased expression of LC3-II and the decreased expression of P62 occurred earlier in p53-/- PFCs than in p53wt PFCs, the relative autophagic flux of p53-/- PFCs was stronger than that of p53wt PFCs in a time-dependent manner. Meanwhile, we observed a visualized increase of autophagosomes in p53-/- PFCs. Moreover, we found greater accumulation of LC3 punctate and acidic vesicular organelle (AVOs) in the cytoplasm of p53-/- PFCs than in that of p53wt PFCs, and these effects were further augmented by Baf A1 treatment. Furthermore, we detected the expression of 6 autophagy signaling pathway-related genes and 14 autophagy-related (ATG) genes by qPCR. We found that the expression patterns of the 6 genes had significant differences in both groups of treated PFCs. These results demonstrated that p53 negatively regulated autophagy and involving the downregulation of LMNA gene by p53 via an unknown pathway, which causes the upregulation of the LC3, ULK1, ATG4B, ATG16L1 and ATG9A genes and the downregulation of the P62 gene. CONCLUSIONS: p53-/- PFCs responded to autophagy earlier than p53wt PFCs, which implied that p53 might inhibit autophagy. The expression patterns of autophagy signaling pathway-related genes and ATG genes were most different between p53-/- and p53wt PFCs. Our study will provide a new biological model and contribute to further study of the molecular basis for p53 and autophagy.

(125)I Seed Permanent Implantation as a Palliative Treatment for Stage III and IV Hypopharyngeal Carcinoma.

OBJECTIVES: The aim of this study was to investigate the feasibility and safety of percutaneous (125)I seed permanent implantation for advanced hypopharyngeal carcinoma from toxicity, tumor response, and short-term outcome. METHODS: (125)I seeds implant procedures were performed under computed tomography for 34 patients with advanced hypopharyngeal carcinoma. We observed the local control rate, overall survival, and acute or late toxicity rate. RESULTS: In the 34 patients (stage III, n=6; stage IV, n=28), the sites of origin were pyriform sinus (n=29) and postcricoid area (n=5). All patients also received one to four cycles of chemotherapy after seed implantation. The post-plan showed that the actuarial D90 of (125)I seeds ranged from 90 to 158 Gy (median, 127 Gy). The mean follow-up was 12.3 months (range, 3.4 to 43.2 months). The local control was 2.1-31.0 months with a median of 17.7 months (95% confidence interval [CI], 13.4 to 22.0 months). The 1-, 2-, and 3-year local controls were 65.3%, 28.6%, and 9.5% respectively. Twelve patients (35%) died of local recurrence, fourteen patients (41%) died of distant metastases, and three patients (9%) died of recurrence and metastases at the same time. Five patients (15%) still survived to follow-up. At the time of analysis, the median survival time was 12.5 months (95% CI, 9.5 to 15.4 months). The 1-, 2-, and 3-year overall survival rates were 55.2%, 20.3%, and 10.9%, respectively. Five patients (15%) experienced grade 3 toxic events and nine patients (26%) have experienced grade 2 toxic events. CONCLUSION: This review shows relatively low toxicity for interstitial (125)I seed implantation in the patients with advanced stage hypopharyngeal cancer. The high local control results suggest that (125)I seed brachytherapy implant as a salvage or palliative treatment for advanced hypopharyngeal carcinoma merit further investigation.

Clinical and prognostic analysis of second primary squamous cell carcinoma of the tongue after radiotherapy for nasopharyngeal carcinoma.

We have investigated the clinical characteristics and prognostic factors of squamous cell carcinoma (SCC) of the tongue after definitive radiotherapy for nasopharyngeal carcinoma, and evaluated the effect of common therapeutic regimens for these patients. We retrospectively reviewed follow-up data for patients whose nasopharyngeal carcinoma had been treated by radiotherapy, and selected the 68 who had then developed SCC of the tongue, in the border of the tongue in half, and in the dorsum in 25 (37%). Eight of the 68 patients had clinical lymph node metastasis (12%), and 45 presented with stage I-II disease at the time of the diagnosis of the SCC (66%). Resection or radiotherapy alone was an effective treatment for patients with stage I-II SCC of the tongue, but patients with stage III-IV disease had a poor prognosis, despite being given multidisciplinary treatment. Multivariate analysis showed that the risk factors that independently influenced the survival of these patients were use of alcohol, recurrence of their nasopharyngeal carcinoma, the latency period, and the clinical TNM stage. Tongue SCC after radiotherapy was generally at an early stage and commonly occurred on the border or the dorsum of the tongue, with few lymph node metastases. Resection or radiotherapy is an effective treatment, and the risk factors that independently influenced the survival of patients indicate that improving the technique of radiotherapy and close follow-up after nasopharyngeal cancer are vitally important.

Use of cyclin D1 in conjunction with human papillomavirus status to predict outcome in oropharyngeal cancer.

There is increasing use of multiple molecular markers to predict prognosis in human cancer. Our aim was to examine the prognostic significance of cyclin D1 and retinoblastoma (pRb) expression in association with human papillomavirus (HPV) status in oropharyngeal squamous cell carcinoma. Clinical records and specimens of 226 patients with follow-up from 1 to 235 months postdiagnosis were retrieved. Tumor HPV status was determined by HPV E6-targeted multiplex real-time PCR/p16 semiquantitative immunohistochemistry and cyclin D1 and pRb expression by semiquantitative immunohistochemistry. Determinants of recurrence and mortality hazards were modeled using Cox regression with censoring at dates of last follow-up. The HPV-positivity rate was 37% (91% type 16). HPV was a predictor of recurrence, an event (recurrence or death) and death after adjustment for clinicopathological variables. There were inverse relationships between HPV status and cyclin D1 and pRb. On univariate analysis, cyclin D1 predicted locoregional recurrence, event and death and pRb predicted event and death. Within the HPV-positive group, after adjusting for clinicopathological factors, patients with cyclin D1-positive cancers had up to a eightfold increased risk of poor outcome relative to those with cyclin D1-negative tumors. However, within the HPV-negative group, there was only a very small adjusted increased risk. A combination of pRb and HPV did not provide additional prognostic information. Our data provide the first evidence that a combination of HPV and cyclin D1 provides more prognostic information in oropharyngeal cancer than HPV alone. If findings are confirmed, treatment based on HPV and cyclin D1 may improve outcomes.

Prognostic significance of vascular endothelial growth factor in squamous cell carcinomas of the tonsil in relation to human papillomavirus status and epidermal growth factor receptor.

BACKGROUND: Angiogenesis markers, vascular endothelial growth factor (VEGF) and microvessel density (MVD) have been associated with prognosis in squamous cell carcinomas (SCCs) of the head and neck. Other prognostic variables such as human papillomavirus (HPV) and epidermal growth factor (EGFR) may also be involved in tumour angiogenesis. This study determined relationships between VEGF, MVD, EGFR, HPV, response to radiotherapy and clinical outcome in 85 tonsillar SCCs. METHODS: HPV status was determined by an HPV multiplex real-time polymerase chain reaction (PCR) assay/p16 immunohistochemistry. Expression of VEGF, CD31 (as marker of MVD) and EGFR was assessed by semiquantitative immunohistochemistry. RESULTS: Strong VEGF expressers were significantly more likely to have higher MVD than were weak expressers. There were no associations between VEGF or MVD and gender, patient age, TNM stage, EGFR expression or HPV status. Tumours with MVD of >15 per high-power field were significantly more likely to be poorly differentiated. There was a significant inverse relationship between EGFR and HPV status. HPV was a strong independent marker of loco-regional recurrence and death. VEGF and EGFR were risk factors for local recurrence and disease-specific death on univariate analysis but the associations weakened after adjustment for HPV. Among patients treated with radiotherapy, VEGF was associated with disease-specific death after adjusting for HPV and TMN stage. High-VEGF-expressing tumours positive for EGFR had a worse prognosis than all other groups combined after adjusting for HPV and TNM stage. CONCLUSIONS: HPV is a stronger prognostic marker than VEGF or EGFR in tonsillar SCCs. VEGF correlates with MVD in these tumours.