Five new glycosides from the culms of Phyllostachys nigra var. henonis.

Five new glycosides, namely methyl 3-methoxybenzoate-4,5-di-O-ß-D-glucopyranoside (1), (1aS,3aS,3R)-3-(4'-O-ß-D-glucopyranosyl-3'-methoxyphenyl)-5,6-dioxa-bicyclo[3.3.0]octane-1-one (2), quinolin-4(1H)-one-3-O-ß-D-glucopyranoside (3), 3-methoxy-propiophenone 4-O-(6'-ß-D-xylopyranosyl)-ß-D-glucopyranoside (4), methyl 3-methoxybenzoate 4-O-(6'-ß-D-xylopyranosyl)-ß-D-glucopyranoside (5), and one known compound, bambulignan B (6) were isolated from the culms of Phyllostachys nigra var. henonis. Their structures were determined using spectroscopic analysis. All compounds were evaluated for their DPPH radical scavenging activity. Compound 6 exhibited antioxidant activity with IC50 value of 59.5 µM (positive control, L-ascorbic acid, IC50 = 12.4 µM; 2,6-ditertbutyl-4-methyl phenol, IC50 = 11.8 µM).

Integrated Metabolomic and Transcriptomic Analysis Reveals the Underlying Antibacterial Mechanisms of the Phytonutrient Quercetin-Induced Fatty Acids Alteration in Staphylococcus aureus ATCC 27217.

The utilization of natural products in food preservation represents a promising strategy for the dual benefits of controlling foodborne pathogens and enhancing the nutritional properties of foods. Among the phytonutrients, flavonoids have been shown to exert antibacterial effects by disrupting bacterial cell membrane functionality; however, the underlying molecular mechanisms remain elusive. In this study, we investigated the effect of quercetin on the cell membrane permeability of Staphylococcus aureus ATCC 27217. A combined metabolomic and transcriptomic approach was adopted to examine the regulatory mechanism of quercetin with respect to the fatty acid composition and associated genes. Kinetic analysis and molecular docking simulations were conducted to assess quercetin's inhibition of ß-ketoacyl-acyl carrier protein reductase (FabG), a potential target in the bacterial fatty acid biosynthesis pathway. Metabolomic and transcriptomic results showed that quercetin increased the ratio of unsaturated to saturated fatty acids and the levels of membrane phospholipids. The bacteria reacted to quercetin-induced stress by attempting to enhance fatty acid biosynthesis; however, quercetin directly inhibited FabG activity, thereby disrupting bacterial fatty acid biosynthesis. These findings provide new insights into the mechanism of quercetin's effects on bacterial cell membranes and suggest potential applications for quercetin in bacterial inhibition.

Prognostic value of systemic inflammatory marker in patients with head and neck squamous cell carcinoma undergoing surgical resection.

Aim: To explore the prognostic value of the systemic inflammatory marker (SIM) based on neutrophil, lymphocyte and monocyte counts in head and neck squamous cell carcinoma (HNSCC) patients. Patients & methods: We retrospectively collected the data of 367 patients with HNSCC who underwent surgery. The Kaplan-Meier survival analysis and Cox regression analysis were conducted on disease-free survival and overall survival. Results: A high SIM (>1.34) was associated with larger tumor size, advanced clinical stage and shorter survival time. The survival analysis showed that only clinical stage and SIM were independent prognostic indicators of disease-free survival and overall survival. Conclusion: The SIM positively correlated with tumor progression and might be a powerful prognostic indicator of poor outcome in patients with HNSCC.

The ubiquitin system: orchestrating cellular signals in non-small-cell lung cancer.

The ubiquitin system, known as a common feature in eukaryotes, participates in multiple cellular processes, such as signal transduction, cell-cycle progression, receptor trafficking and endocytosis, and even the immune response. In lung cancer, evidence has revealed that aberrant events in ubiquitin-mediated processes can cause a variety of pathological outcomes including tumorigenesis and metastasis. Likewise, ubiquitination on the core components contributing to the activity of cell signaling controls bio-signal turnover and cell final destination. Given this, inhibitors targeting the ubiquitin system have been developed for lung cancer therapies and have shown great prospects for clinical application. However, the exact biological effects and physiological role of the drugs used in lung cancer therapies are still not clearly elucidated, which might seriously impede the progress of treatment. In this work, we summarize current research advances in cell signal regulation processes mediated through the ubiquitin system during the development of lung cancer, with the hope of improving the therapeutic effects by means of aiming at efficient targets.

Circulating tumor cells as an independent prognostic factor in advanced colorectal cancer: a retrospective study in 121 patients.

PURPOSE: This study aimed to evaluate the prognostic value of circulating tumor cells (CTCs) in advanced colorectal cancer (CRC) patients during chemotherapy course. METHODS: From January 2016 to September 2017, the clinicopathological variables, such as gender, age, tumor location, tumor de-differentiation, depth of invasion, lymphatic invasion, distant metastasis, TNM stage, CTCs enumeration during 2-6 cycles of chemotherapy, and serum carcinoembryonic antigen (CEA) level during the same period, of 121 newly acquired and histopathologically confirmed CRC patients were collected from the Shanghai Ninth People's Hospital affiliated to Shanghai Jiao Tong University School of Medicine. All patients were followed up for survival until the end of November 2018. Statistical analysis focused on the associations between CTCs counts and clinicopathological variables. Overall survival (OS) and progression-free survival (PFS) among different prognostic factors were calculated using the Kaplan-Meier method, and the differences between the survival curves were compared by using the log-rank test. Factors of prognostic significance were investigated with the multivariate Cox regression analysis. RESULTS: Here, 71 of 121 patients were CTC-positive, in which CTC-positive rate was positively correlated with the depth of invasion, lymphatic invasion, distant metastasis, TNM stage, and serum CEA level (P < 0.05 for all). However, no significant difference was found between CTC-positive and other clinicopathological variables (P > 0.05 for all), such as gender, age, tumor location, and tumor de-differentiation. CTCs counts gradually increased with the advancement of depth of invasion (P = 0.002), lymphatic invasion (P = 0.004), distant metastasis (P = 0.007), TNM stage (P = 0.001), serum CEA level (P = 0.001), and decreased tumor de-differentiation (P = 0.011). Furthermore, the Kaplan-Meier survival curves showed that patients with CTC-positive had a significantly unfavorable PFS (14 vs. 23 months, P = 0.001) and OS (18 vs. 25 months, P = 0.003). The multivariate Cox regression analyses revealed that the presence of CTCs during chemotherapy was an independent factor for unfavorable PFS (hazard ratio (HR) 2.682, P = 0.017, 95% confidence interval (CI) 1.193-6.029) and OS (HR 2.790, P = 0.048, 95% CI 1.010-7.705) in advanced CRC patients. CONCLUSIONS: This study provided an evidence that the presence of CTCs may be valuable for predicting survival outcome, and CTCs was associated with unfavorable survival in advanced CRC patients during chemotherapy.

Sumoylation of EphB1 Suppresses Neuroblastoma Tumorigenesis via Inhibiting PKCγ Activation.

BACKGROUND/AIMS: An increasing number of studies have linked erythropoietin-producing hepatocellular carcinoma (Eph) family receptor tyrosine kinases to cancer progression. However, little knowledge is available about the regulation of their functions in cancer. METHODS: SUMOylation was analyzed by performing Ni2+-NTA pull-down assay and immunoprecipitation. Cell proliferation, anchorage-independent growth, and tumorigenesis in vivo were examined by cell counting kit-8, soft agar colony formation assay, and a xenograft tumor mouse model, respectively. RESULTS: We found that EphB1 was post-translationally modified by the small ubiquitin-like modifier (SUMO) protein at lysine residue 785. Analysis of wild-type EphB1 and SUMOylation-deficient EphB1 K785R mutant revealed that SUMOylation of EphB1 suppressed cell proliferation, anchorage-independent cell growth, and xenograft tumor growth. Mechanistic study showed that SUMOylation of EphB1 repressed activation of its downstream signaling molecule PKCγ, and consequently inhibited tumorigenesis. A reciprocal regulatory loop between PKCγ and SUMOylation of EphB1 was also characterized. CONCLUSION: Our findings identify SUMO1 as a novel key regulator of EphB1-mediated tumorigenesis.

SUMO1 modification of KHSRP regulates tumorigenesis by preventing the TL-G-Rich miRNA biogenesis.

BACKGROUND: MicroRNAs (miRNAs) are important regulators involved in diverse physiological and pathological processes including cancer. SUMO (small ubiquitin-like modifier) is a reversible protein modifier. We recently found that SUMOylation of TARBP2 and DGCR8 is involved in the regulation of the miRNA pathway. KHSRP is a single stranded nucleic acid binding protein with roles in transcription and mRNA decay, and it is also a component of the Drosha-DGCR8 complex promoting the miRNA biogenesis. METHODS: The in vivo SUMOylation assay using the Ni2+-NTA affinity pulldown or immunoprecipitation (IP) and the in vitro E.coli-based SUMOylation assay were used to analyze SUMOylation of KHSRP. Nuclear/Cytosol fractionation assay and immunofluorescent staining were used to observe the localization of KHSRP. High-throughput miRNA sequencing, quantantive RT-PCR and RNA immunoprecipitation assay (RIP) were employed to determine the effects of KHSRP SUMO1 modification on the miRNA biogenesis. The soft-agar colony formation, migration, vasculogenic mimicry (VM) and three-dimensional (3D) cell culture assays were performed to detect the phenotypes of tumor cells in vitro, and the xenograft tumor model in mice was conducted to verify that SUMO1 modification of KHSRP regulated tumorigenesis in vivo. RESULTS: KHSRP is modified by SUMO1 at the major site K87, and this modification can be increased upon the microenvironmental hypoxia while reduced by the treatment with growth factors. SUMO1 modification of KHSRP inhibits its interaction with the pri-miRNA/Drosha-DGCR8 complex and probably increases its translocation from the nucleus to the cytoplasm. Consequently, SUMO1 modification of KHSRP impairs the processing step of pre-miRNAs from pri-miRNAs which especially harbor short G-rich stretches in their terminal loops (TL), resulting in the downregulation of a subset of TL-G-Rich miRNAs such as let-7 family and consequential tumorigenesis. CONCLUSIONS: Our data demonstrate how the miRNA biogenesis pathway is connected to tumorigenesis and cancer progression through the reversible SUMO1 modification of KHSRP.

MiR-130b suppresses prostate cancer metastasis through down-regulation of MMP2.

Prostate cancer (PCa) is the most prevalent malignant carcinoma among males in western countries. Currently no treatments can cure advanced prostate cancers, so new diagnostic and therapeutic strategies are in urgent need. At present limited knowledge is available concerning the roles of dysregulated microRNAs in prostate cancer metastasis. In this study, we found that the expression of miR-130b was significantly down-regulated in prostate cancer cell lines and clinical prostate cancer tissues. Enforced over-expression of miR-130b in prostate cancer cells suppressed whereas knock-down of miR-130b increased cell migration and invasion. Using mouse model, we revealed that miR-130b-expressed prostate cancer cells displayed significant reduction in tumor metastasis. Furthermore, we identified and validated matrix metalloproteinase-2 (MMP2) as a direct target of miR-130b. Ectopic expression of MMP2 rescued miR-130b-suppressed cell migration and invasion, and knock-down of MMP2 antagonized the effect of silencing miR-130b.Taken together, our data reveal for the first time that miR-130b exerts a suppressive effect in prostate cancer metastasis through down-regulation of MMP2.

Leonurine hydrochloride induces apoptosis of H292 lung cancer cell by a mitochondria-dependent pathway.

CONTEXT: Leonurine hydrochloride (LH), a major alkaloid compound extracted from Leonurus japonicas Houtt. (Labiatae), is considered to have antitumor roles. OBJECTIVE: This study investigated its effects on human non-small cell lung cancer (NSCLC) H292 cells and illustrated the possible mechanism involved. MATERIALS AND METHODS: After treatment with different concentrations of LH (0, 10, 25, and 50 µmol/L) for 6, 12, 24, 48, and 72 h, the cell viability was assessed by the MTT assay. After exposed to different doses of LH for 24 h, cell-cycle distribution, cell apoptosis, mitochondrial membrane potential (MMP), and reactive oxygen species (ROS) were monitored by flow cytometry. RT-PCR and western blot were used to detect the expression of apoptosis-related genes. RESULTS: LH significantly inhibited the proliferation of H292 cells in a time- and dose-dependent manner, and induced G0/G1 cell-cycle arrest. Coincidentally, LH treatment at a dose of 10, 25, and 50 µmol/L for 24 h increased apoptotic ratio from 4.9 ± 0.43% to 11.5 ± 1.12%, 19.3 ± 1.16%, and 61.3 ± 6.69%, respectively. The inhibition effect of LH on H292 cells was associated with the loss of MMP and the generation of ROS. The phosphorylation level of p38 was increased and Akt phosphorylation was reduced by LH treatment. Furthermore, LH treatment increased the expression levels of caspase-3, caspase-9 and Bax/Bcl-2. CONCLUSIONS: LH inhibits the proliferation and induces the apoptosis of H292 cells in a mitochondria-dependent pathway, and the specific mechanism need to be further explored.

SUMOylation of Grb2 enhances the ERK activity by increasing its binding with Sos1.

BACKGROUND: Grb2 (Growth factor receptor-bound protein 2) is a key adaptor protein in maintaining the ERK activity via linking Sos1 (Son of sevenless homolog 1) or other proteins to activated RTKs, such as EGFR. Currently, little knowledge is available concerning the post-translational modification (PTM) of Grb2 except for its phosphorylation. Since emerging evidences have highlighted the importance of SUMOylation (Small ubiquitin-related modifier), a reversible PTM, in modulating protein functions, we wondered if Grb2 could be SUMOylated and thereby influences its functions especially involved in the Ras/MEK/ERK pathway. METHODS: SUMOylation of Grb2 was analyzed with the in vivo SUMOylation assay using the Ni2+-NTA affinity pulldown and the in vitro E.coli-based SUMOylation assay. To test the ERK activity and cell transformation, the murine fibroblast cell line NIH/3T3 and the murine colon cancer cell line CMT-93 were used for the experiments including Grb2 knockdown, ectopic re-expression, cell transformation and migration. Immunoprecipitation (IP) was employed for seeking proteins that interact with SUMO modified Grb2. Xenograft tumor model in mice was conducted to verify that Grb2 SUMOylation regulated tumorigenesis in vivo. RESULTS: Grb2 can be SUMOylated by SUMO1 at lysine 56 (K56), which is located in the linker region between the N-terminal SH3 domain and the SH2 domain. Knockdown of Grb2 reduced the ERK activity and suppressed cell motility and tumorigenesis in vitro and in vivo, which were all rescued by stable ectopic re-expression of wild-type Grb2 but not the mutant Grb2K56R. Furthermore, Grb2 SUMOylation at K56 increased the formation of Grb2-Sos1 complex, which sequentially leads to the activation of Ras/MEK/MAPK pathway. CONCLUSIONS: Our results provide evidences that Grb2 is SUMOylated in vivo and this modification enhances ERK activities via increasing the formation of Grb2-Sos1 complex, and may consequently promote cell motility, transformation and tumorigenesis.

Isolation and identification of three new phenylpropanoids from the culms of phyllostachys nigra var. henonis (mitford) Rendle.

Three new phenylpropanoids, namely (7'R,8'R) guaiacylglycerol 4'-O-ß-D-[6″-O-(4-O-ß-D-glucopyranosyl)-p-hydroxyl-benzoyl]-glucopyranoside (1), (7 R,8R) guaiacylglycerol 8-O-1'-(2',6'-dimethoxy-4'-O-ß-D-glucopyranosyl)-benzene (2), (7'R,8'R) guaiacylglycerol 4'-O-ß-D-[6″-O-3,5-dimethoxy-4-hydroxylbenzoyl]-gluco-pyranoside (3), along with one known phenylpropanoid (4) were isolated from the ethanol extract of Phyllostachys nigra var. henonis fresh culm. The structures of all compounds were determined by analysis of UV, 1D NMR, 2D NMR, HR-ESI-MS and CD data. All compounds were evaluated for their DPPH radical scavenging activity. Compound 2 (IC50 54.9 µM) and 3 (IC50 77.2 µM) exhibited moderate antioxidant activity compared with two positive control compounds L-ascorbic acid (IC50 15.5 µM) and 2,6-ditertbutyl-4-methyl phenol (IC50 19.1 µM).

Acetylated KHSRP impairs DNA-damage-response-related mRNA decay and facilitates prostate cancer tumorigenesis.

Androgen-regulated DNA damage response (DDR) is one of the essential mechanisms in prostate cancer (PCa), a hormone-sensitive disease. The heterogeneous nuclear ribonucleoprotein K (hnRNPK)-homology splicing regulatory protein known as far upstream element-binding protein 2 (KHSRP) is an RNA-binding protein that can attach to AU-rich elements in the 3' untranslated region (3'-UTR) of messenger RNAs (mRNAs) to mediate mRNA decay and emerges as a critical regulator in the DDR to preserve genome integrity. Nevertheless, how KHSRP responds to androgen-regulated DDR in PCa development remains unclear. This study found that androgen can significantly induce acetylation of KHSRP, which intrinsically drives tumor growth in xenografted mice. Moreover, enhanced KHSRP acetylation upon androgen stimuli impedes KHSRP-regulated DDR gene expression, as seen by analyzing RNA sequencing (RNA-seq) and Gene Set Enrichment Analysis (GSEA) datasets. Additionally, NAD-dependent protein deacetylase sirtuin-7 (SIRT7) is a promising deacetylase of KHSRP, and androgen stimuli impairs its interaction with KHSRP to sustain the increased KHSRP acetylation level in PCa. We first report the acetylation of KHSRP induced by androgen, which interrupts the KHSRP-regulated mRNA decay of the DDR-related genes to promote the tumorigenesis of PCa. This study provides insight into KHSRP biology and potential therapeutic strategies for PCa treatment, particularly that of castration-resistant PCa.

[EGFR-ERK signaling pathway down-regulates miRNA-145 in lung cancer cells].

OBJECTIVE: To investigate the relationship between EGFR activation and down-regulation of miRNA-145 in lung cancer. METHODS: Normal human lung epithelia cell line (BEAS-2B), human lung adenocarcinoma cell lines with wild-type EGFR (A549 and H292) and human lung adenocarcinoma cell lines with EGFR mutation (H1975 and H1650) were chosen in this study. The levels of miRNA-145 and p-EGFR were determined by quantitative real-time PCR (qRT-PCR) and Western blotting, respectively, and the relationship between p-EGFR and miRNA-145 levels was analyzed. The miRNA-145 levels were determined by qRT-PCR after activating EGFR with EGF or blocking EGFR signal pathway with AG1478. In addition, ERK1/2 inhibitor U0126 was used to inhibit ERK1/2 activation and then the expression of miRNA-145 was detected. RESULTS: The miRNA-145 levels were closely negatively related with p-EGFR in lung cancer cells (r = -0.926, P = 0.024). EGF down-regulated miRNA-145 expression, particularly in BEAS-2B cells (53.0%; t = 30.993, P = 0.001) and A549 cells (42.6%; t = 14.326, P = 0.005).The miRNA-145 was up-regulated after inhibiting p-EGFR with AG1478, and significantly enhanced by 67.5% in H1975 cells when treated with AG1478 (t = 8.269, P = 0.014). The ERK1/2 signal pathway was activated by p-EGFR. U0126 restored the miRNA-145 down-regulation induced by EGFR-activation in lung cancer cells. CONCLUSION: The activation of EGFR down-regulates miRNA-145 expression through ERK1/2 in lung cancer cells.

[Effects of AG1478 on the expression of FOXM1 gene via FOXO3a in non-small cell lung cancer cells].

OBJECTIVE: To explore the effects of EGFR-TKI AG1478 on the expression of FoxMl and FOXO3a genes in non-small cell cancer (NSCLC) cell lines, and explore the effect on cell proliferation and drug sensitivity to AG1478 after down-regulation of FOXMl and FOXO3a expression by RNAi technique. METHODS: Human lung cancer cells were treated with AG1478 at different concentrations. RT-PCR and Western blot were used to examine the expression of P-EGFR, FOXM1, FOXO3a mRNA and protein. After transient transfection of FOXM1 and FOXO3a siRNA, RT-PCR and Western blot were employed to determine the transfection efficiency and expression of the related proteins. CCK-8 assay, colony formation assay and flow cytometry were performed to evaluate the cell proliferation, colony formation ability and the changes in cell cycle distribution. RESULTS: The expressions of FOXM1 mRNA and protein were inhibited by AG1478 in a dose-dependent manner (both P < 0.05). After transfection with FOXM1 siRNA, the expressions of FOXM1 mRNA and protein, and proteins of cyclin B1, c-Myc, and Bcl-2 were significantly down-regulated, and the expressions of p21 and cleaved-PARP proteins were significantly up-regulated (all P < 0.05). The colony number of FOXM1siRNA transfection group was 37.3 ± 8.6, significantly lower than that of the blank control (135.3 ± 7.0) and negative control group (125.3 ± 7.5, P < 0.05). The colony formation inhibition rate was (7.40 ± 0.94)% in the negative control group and (72.4 ± 6.09)% in the FOXM1 siRNA transfection group. FOXM1siRNA transfection induced cell cycle arrest at G2/M phase with a percentage of (55.6 ± 4.83)%, significantly higher than that of the blank control [(24.30 ± 1.95)%] and negative control group [(21.3 ± 2.06)%, P < 0.05]. Additionally, the FOXM1siRNA transfection significantly increased the chemosensitivity of A549 cells to AG1478 (P < 0.05). Besides, AG1478 induced expression and nuclear relocation of FOXO3a. After the FOXO3a siRNA transfection, the expression of FOXM1 protein was significantly up-regulated, and resulted in a reduction of AG1478-induced inhibition of FOXM1. CONCLUSIONS: The expression of FOXM1 is down-regulated by AG1478 via FOXO3a in the NSCLC cell lines, and then increases the chemosensitivity of A549 cells to AG1478. It suggests that FOXM1 could be a potential target for the therapy and drug exploitation for NSCLC.

Fbxo45-mediated NP-STEP46 degradation via K6-linked ubiquitination sustains ERK activity in lung cancer.

Lung cancer is one of the most threatening malignant tumors to human health. Epidermal growth factor receptor (EGFR)-targeted therapy is a common and essential means for the clinical treatment of lung cancer. However, drug resistance has always affected the therapeutic effect and survival rate in non-small cell lung cancer (NSCLC). Tumor heterogeneity is a significant reason, yielding various drug resistance mechanisms, such as EGFR-dependent or -independent extracellular signal-regulated kinase 1 and/or 2 (ERK1/2) activation in NSCLC. To examine whether this aberrant activation of ERK1/2 is related to the loss of function of its specific phosphatase, a series of in vitro and in vivo assays were performed. We found that F-box/SPRY domain-containing protein 1 (Fbxo45) induces ubiquitination of NP-STEP46 , an active form of striatal-enriched protein tyrosine phosphatase, with a K6-linked poly-ubiquitin chain. This ubiquitination led to proteasome degradation in the nucleus, which then sustains the aberrant level of phosphorylated-ERK (pERK) and promotes tumor growth of NSCLC. Fbxo45 silencing can significantly inhibit cell proliferation and tumor growth. Moreover, NSCLC cells with silenced Fbxo45 showed great sensitivity to the EGFR tyrosine kinase inhibitor (TKI) afatinib. Here, we first report this critical pERK maintenance mechanism, which might be independent of the upstream kinase activity in NSCLC. We propose that inhibiting Fbxo45 may combat the issue of drug resistance in NSCLC patients, especially combining with EGFR-TKI therapy.

SUMOylation is essential for Sirt2 tumor-suppressor function in neuroblastoma.

SUMOylation is an important post-translational modification that participates in a variety of cellular physiological and pathological processes in eukaryotic cells. Sirt2, a NAD+-dependent deacetylase, usually exerts a tumor-suppressor function. However, the role of SUMOylation in cancer cells is not fully known. In this study, we found that SUMOylation can occur in the Sirt2 protein at both lysine 183 and lysine 340 sites. SUMOylation did not affect Sirt2 localization or stability but was involved in P38-mTORC2-AKT cellular signal transduction via direct deacetylation on a new substrate MAPK/P38. SUMOylation-deficient Sirt2 lost the capability of suppressing tumor processes and showed resistance to the Sirt2-specific inhibitor AK-7 in neuroblastoma cells. Here, we revealed the important function of Sirt2-SUMOylation, which is closely associated with cellular signal transduction and is essential for suppressing tumorigenesis in neuroblastoma.

Positive feedback between ROS and cis-axis of PIASxα/p38α-SUMOylation/MK2 facilitates gastric cancer metastasis.

MAPK/p38 is an important mammalian signaling cascade that responds to a variety of intracellular or extracellular stimuli, such as reactive oxygen species (ROS), and participates in numerous physiological and pathological processes. However, the biological function of p38 in different tumors, and even at different stages of the same tumor, remains elusive. To further understand the regulatory mechanism of p38 and oxidative stress in the occurrence and development of gastric cancer, we report SUMOylation as a novel post-translational modification occurring on lysine 152 of MAPK14/p38α through immunoprecipitation and series of pull-down assays in vitro and in vivo. Importantly, we determine that p38α-SUMOylation functions as an authentic sensor and accelerator of reactive oxygen species generation via interaction with and activation of MK2 in the nucleus, and the ROS accumulation, in turn, promotes the SUMOylation of p38α by stabilizing the PIASxα protein. This precise regulatory mechanism is exploited by gastric cancer cells to create an internal environment for survival and, ultimately, metastasis. This study reveals novel insights into p38α-SUMOylation and its association with the intracellular oxidative stress response, which is closely related to the processes of gastric cancer. Furthermore, the PIASxα/p38α-SUMOylation/MK2 cis-axis may serve as a desirable therapeutic target in gastric cancer as targeting PIASxα, MK2, or a specific peptide region of p38α may reconcile the aberrant oxidative stress response in gastric cancer cells.

Neutrophil-Lymphocyte Ratio and Circulating Tumor Cells Counts Predict Prognosis in Gastrointestinal Cancer Patients.

PURPOSE: The purpose of this study is to explore the prognostic value of associating pre-treatment neutrophil-lymphocyte ratio (NLR) with circulating tumor cells counts (CTCs) in patients with gastrointestinal cancer. MATERIALS AND METHODS: We collected the related data of 72 patients with gastric cancer (GC) and colorectal cancer (CRC) who received different therapies from August 2016 to October 2020, including age, gender, primary tumor location, TNM stage, tumor-differentiation, NLR, CTCs, disease-free survival (DFS) and overall survival (OS). We chose the optimal cut-off value of NLR >3.21 or NLR ≤3.21 and CTC >1 or CTC ≤1 by obtaining receiver operating characteristic (ROC) curve. The Kaplan-Meier survival analysis and Cox regression analysis were used to analyze DFS and OS. To clarify the role of the combination of NLR and CTCs counts in predicting the prognosis, we analyzed the DFS and OS when associated NLR and CTCs counts. RESULTS: A high NLR (>3.21) was associated with shorter DFS (P <0.0001) and OS (P <0.0001). Patients with high CTCs level (>1) had shorter DFS (P = 0.001) and OS (P = 0.0007) than patients with low CTCs level. Furthermore, patients who had both higher NLR and higher CTCs counts had obvious shorter DFS (P <0.0001) and OS (P <0.0001). CONCLUSIONS: Patients with higher NLR and more CTCs respectively tended to have poor prognosis with shorter DFS and OS, which might be regarded as predictors of gastrointestinal cancer. In particular, associating NLR and CTCs counts might be a reliable predictor in patients with gastrointestinal cancer.

Circulating Tumor Cells Correlate With Prognosis in Head and Neck Squamous Cell Carcinoma.

BACKGROUND: To investigate the relationship of circulating tumor cells (CTCs) and the clinical characteristic parameters and prognosis in patients with head and neck squamous cell carcinoma (HNSCC). METHODS: The retrospective clinical study included 95 patients with HNSCC who after surgery in Shanghai Ninth People's Hospital affiliated to Shanghai Jiao Tong University School of Medicine between December 2015 and December 2016. All patients were followed up for survival until the end of June 2019. The CTCs detection was performed by negative enrichment (NE) immunofluorescence-in situ hybridization (im-FISH) of chromosome 8. RESULTS: Patients with higher CTCs counts are associated with a worse prognosis with an area under the receiver operator characteristic (ROC) curve of 0.756 [95% confidence interval (CI) 0.640-0.872, p = 0.001]. The CTCs-positive rate of HNSCC patients was 58.9% (56/95) by using the cut-point of 3. Both the chi-square test and binary logistic regression analysis showed that the N stage and clinical stage were significantly associated with CTCs-positive in patients with HNSCC (p < 0.05). Further Non-parametric test analysis indicated that more CTCs counts were detected in late N and clinical stages patients (p < 0.001). The Kaplan-Meier survival analysis indicated that CTCs-positive were correlated with shorter progression-free survival (PFS) (p < 0.001) and overall survival (OS) (p = 0.001). Further, the CTCs-positive was an independent prognostic factor for PFS and OS according to the Cox multivariate regression analysis (p < 0.05). CONCLUSION: More CTCs were associated with N stage, clinical stage, poor prognosis in patients with HNSCC, which might be used as a prognostic biomarker.

SUMOylation modulates the LIN28A-let-7 signaling pathway in response to cellular stresses in cancer cells.

LIN28A is a conserved RNA-binding protein that inhibits the biogenesis of let-7 microRNAs, thus promoting cancer progression. However, mechanisms underlying the activation of the LIN28A-let-7 signaling pathway remain poorly understood. Here, we show that LIN28A is SUMOylated in vivo and in vitro at K15, which is increased by hypoxia but reduced by chemotherapy drugs such as Cisplatin and Paclitaxel. SUMOylation of LIN28A aggravates its inhibition of let-7 maturation, resulting in a stark reduction in let-7, which promotes cancer cell proliferation, migration, invasion, and tumor growth in vivo. Mechanistically, SUMOylation of LIN28A increases its binding affinity with the precursor let-7 (pre-let-7), which subsequently enhances LIN28A-mediated recruitment of terminal uridylyltransferase TUT4 and simultaneously blocks DICER processing of pre-let-7, thereby reducing mature let-7 production. These effects are abolished in SUMOylation-deficient mutant LIN28A-K15R. In summary, these findings shed light on a novel mechanism by which SUMOylation could regulate the LIN28A-let-7 pathway in response to cellular stress in cancer cells.