SPDEF is overexpressed in gastric cancer and triggers cell proliferation by forming a positive regulation loop with FoxM1.

The SAM-pointed domain-containing ETS transcription factor (SPDEF) is an epithelial-specific transcription factor of the E26 transformation-specific (ETS) family, which binds the target gene through the high-affinity sequence of GGAT. It is suggested that SPDEF targets the promoter activity of Forkhead Box M1 (FoxM1), which has been proven to be highly expressed in gastric cancer. We found that SPDEF was overexpressed both at the messenger RNA (mRNA) and at the protein level in human gastric cancer species. The gastric cancer cells transfected with the SPDEF expression plasmid or SPDEF small interfering RNA (siRNA) led to observations on the clone genetics assay that indicated the promotion or the inhibition of gastric cancer cell proliferation, respectively. Both mRNA and protein levels of FoxM1 were regulated by SPDEF in gastric cancer cells and FoxM1 was also overexpressed in the corresponding human gastric cancer species. The overexpression and inhibition of FoxM1 could upregulate and downregulate the mRNA and protein levels of SPDEF expression, respectively. The recovery experiments verified that the overexpression of FoxM1 could at least partially revert both the expression of SPDEF and the proliferation of the cell lines even with the siRNA inhibition of SPDEF. The result of the dual luciferase activity assay showed that SPDEF bound to the promoter of FoxM1 and activated it. FoxM1 might also bind to the promoter of SPDEF to affect its expression. The results were checked in vivo. In conclusion, SPDEF is overexpressed in gastric cancer, which can form a positive regulation loop with FoxM1 to promote gastric carcinogenesis.

Overexpression of ETV4 is associated with poor prognosis in prostate cancer: involvement of uPA/uPAR and MMPs.

ETS gene fusions involving ERG, ETV1, ETV4, ETV5, and FLI1 define a distinct class of prostate cancer (PCa), and this might have a bearing on diagnosis, prognosis, and rational therapeutic targeting. In the current study, we focused on the clinicopathological significance of ETV4 in Chinese PCa patients and the mechanisms whereby ETV4 overexpression mediates tumor invasion in the prostate. Overall, ETV4 overexpression was identified in 30.4 % (45/148) of PCa cases by immunohistochemistry. Accordingly, ETV4 was rearranged in only 1.6 % (2/128) of PCa patients. Clinically, ETV4 overexpression was significantly correlated with Gleason score (P = 0.045) and pathological tumor stage (P = 0.041). Multivariate Cox regression analysis indicated that ETV4 is an unfavorable independent prognostic factor (P = 0.040). Functional studies further showed that small interfering RNA (siRNA) knockdown of ETV4 significantly decreases proliferation and invasion of PC-3 cell and partially reverses epithelial-mesenchymal transition in vitro. Notably, ETV4 knockdown significantly downregulated expression of urokinase plasminogen activator (uPA) and its receptor (uPAR) at messenger RNA (mRNA) and protein levels. Chromatin immunoprecipitation assay demonstrated that ETV4 regulates uPA expression through direct binding to its promoter region. Additionally, ETV4 knockdown was also observed to significantly inhibit expression of matrix metalloproteinase (MMP)-2 and MMP-9. In conclusion, for the first time, our study suggested that ETV4 is an independent poor prognostic factor in Chinese PCa patients. Silencing of ETV4 suppresses invasion of PCa cells by inhibiting the expression of uPA/uPAR as well as MMPs. Further studies will be needed to determine whether ETV4 could be regarded as a potential target for the management and prevention of PCa.

A modified technique for expanded polytetrafluoroethylene shaping in chin augmentation: parallel groove carving technique.

OBJECTIVE: In the current study, we restricted our focus on a modified approach to address the poor curved attachment of expanded polytetrafluoroethylenein chin augmentation. METHOD: The implant is shaped generally in accordance with the chin, followed by 5-to-8 longitudinally parallel "V"-grooves carved in the median of posterior site where the implant directly attaches to the mandible. Thus, it enhances bend ductility of the prosthesis and renders better attachment from the curved surface of prosthesis to the mandibular embedded region. RESULTS: This procedure was performed in 15 patients. After follow-up for 2 to 6 months, there were no complications observed postoperatively including mobilization, dead space, subcutaneous dropsy, topical infection, or palpable edges in the subcutaneous area. CONCLUSIONS: The introduction of longitudinally parallel V-groove technique provides an effective method for avoidance of increasing hardness, decreasing flexibility, and palpable edges after implantation.As a novel and effective technique, it is beneficial for better attachment and satisfactory outcome without causing extra expenses.

RUNX3 regulates vimentin expression via miR-30a during epithelial-mesenchymal transition in gastric cancer cells.

Runt-related transcription factor 3 (RUNX3) is a putative tumour suppressor via regulating the expression of a series of target genes. Clinical studies demonstrated that loss of RUNX3 expression is associated with gastric cancer progression and poor prognosis, but the underlying mechanism is not entirely clear. Accumulating evidence shows that the epithelial-mesenchymal transition (EMT) plays an important role in cancer relapse and metastasis. Therefore, we addressed whether RUNX3 has a role in the EMT in gastric cancer. Knockdown of RUNX3 promoted cell invasion and increased the protein expression of the mesenchymal marker vimentin in human gastric cancer cells. Overexpression of RUNX3 suppressed cell invasion and decreased the protein expression of vimentin in the cells and inhibited gastric cancer cells colonization in nude mice. Furthermore, overexpression of RUNX3 increased the expression of microRNA-30a (miR-30a), and miR-30a directly targeted the 3' untranslated region of vimentin and decreased its protein level. miR-30a inhibitor abrogated RUNX3-mediated inhibition of cell invasion and downregulation of vimentin. Thus, RUNX3 suppressed gastric cancer cell invasion and vimentin expression by activating miR-30a. In gastric cancer patients, levels of RUNX3 were positively correlated with miR-30a and negatively associated with the levels of vimentin. Collectively, our data suggest a novel molecular mechanism for the tumour suppressor activity of RUNX3. Effective therapy targeting the RUNX3 pathway may help control gastric cancer cell invasion and metastasis by inhibiting the EMT.

Critical role of histone demethylase RBP2 in human gastric cancer angiogenesis.

BACKGROUND: The molecular mechanisms responsible for angiogenesis and abnormal expression of angiogenic factors in gastric cancer, including vascular endothelial growth factor (VEGF), remain unclear. The histone demethylase retinoblastoma binding protein 2 (RBP2) is involved in gastric tumorgenesis by inhibiting the expression of cyclin-dependent kinase inhibitors (CDKIs). METHODS: The expression of RBP2, VEGF, CD31, CD34 and Ki67 was assessed in 30 human gastric cancer samples and normal control samples. We used quantitative RT-PCR, western blot analysis, ELISA, tube-formation assay and colony-formation assay to characterize the change in VEGF expression and associated biological activities induced by RBP2 silencing or overexpression. Luciferase assay and ChIP were used to explore the direct regulation of RBP2 on the promoter activity of VEGF. Nude mice and RBP2-targeted mutant mice were used to detect the role of RBP2 in VEGF expression and angiogenesis in vivo. RESULTS: RBP2 and VEGF were both overexpressed in human gastric cancer tissue, with greater microvessel density (MVD) and cell proliferation as compared with normal tissue. In gastric epithelial cell lines, RBP2 overexpression significantly promoted the expression of VEGF and the growth and angiogenesis of the cells, while RBP2 knockdown had the reverse effect. RBP2 directly bound to the promoter of VEGF to regulate its expression by histone H3K4 demethylation. The subcutis of nude mice transfected with BGC-823 cells with RBP2 knockdown showed reduced VEGF expression and MVD, with reduced carcinogenesis and cell proliferation. In addition, the gastric epithelia of RBP2 mutant mice with increased H3K4 trimethylation showed reduced VEGF expression and MVD. CONCLUSIONS: The promotion of gastric tumorigenesis by RBP2 was significantly associated with transactivation of VEGF expression and elevated angiogenesis. Overexpression of RBP2 and activation of VEGF might play important roles in human gastric cancer development and progression.

Retroperitoneal Lymph Node Dissection: Perioperative Management and Updates on Surgical Techniques.

Retroperitoneal lymph node dissection (RPLND) has been an integral part of a multimodal treatment strategy in testicular cancer. Surgeons, over the last decade, have advanced the understanding of RPLND by adopting perioperative care pathways, innovative biomarkers, surgical techniques, and developing algorithms for managing complications. This review summarizes updates on various aspects including the enhanced recovery after surgery pathway, imaging techniques, surgical approaches, dissection templates, and the management of complications. We conclude that RPLND has undergone significant evolution and refinement in the modern era and will continue to hold a critical role in the care of patients with testicular cancer.

MiR-370 sensitizes chronic myeloid leukemia K562 cells to homoharringtonine by targeting Forkhead box M1.

BACKGROUND: Homoharringtonine (HHT) is a kind of cephalotaxus alkaloid used in traditional Chinese medicine. Although HHT has been successfully used as a therapeutic agent for leukemia, the drug resistance and toxicity are major concerns. MicroRNAs (miRNAs) have been identified to modulate cellular sensitivity to anticancer drugs. We examined the synergistic action between miR-370 and HHT in vitro and in vivo. METHODS: The synergistic action between miR-370 and HHT was examined by flow cytometry. The effect of HHT on miR-370 expression was determined by quantitative RT-PCR (qRT-PCR). The expression of miR-370 and Forkhead box M1 (FoxM1) in 23 patients with newly diagnosed chronic-phase chronic myeloid leukemia (CML-CP) and 10 patients with blast-crisis CML (CML-BP) as well as miR-370-targeted FoxM1 was determined by qRT-PCR and western blot analysis. RESULTS: Ectopic expression of miR-370 sensitized the CML K562 cell line to HHT by targeting FoxM1, the major regulator in cell proliferation and apoptosis. miR-370 significantly promoted HHT-mediated cell apoptosis and miR-370 and HHT cooperated in affecting FoxM1 expression. As well, miR-370 was moderately upregulated after HHT treatment in K562 cells. In addition, the expression of miR-370 was significantly reduced in CML patients as compared with healthy controls. Furthermore, the expression of miR-370 was lower in CML-BP than CML-CP patients. CONCLUSIONS: MiR-370 sensitized K562 cells to HHT by inducing apoptosis in part by downregulation of FoxM1 expression. These findings may provide further information for CML treatment with HHT.

Rejuvenation surgery through blepharoplasty incision for mild to moderate upper eyelid sagging in older Asian patients.

OBJECTIVES: The objective of this study was to evaluate the clinical outcome of rejuvenation surgery through double eyelid incision instead of face-lifting for the correction of different types of the upper eyelid sagging in older East Asian patients. MATERIALS AND METHODS: A total of 40 patients (80 aging upper eyelids) with upper eyelid sagging were retrospectively examined. The age of the patients ranged from 53 to 85 years (mean age, 65 y). After a thorough preoperative evaluation, the corresponding operations were performed and the follow-up results were obtained. RESULTS: The operation of each patient with a mean follow-up period of 6 months was combined for a total of 80 rejuvenation operations. A total of 34 patients (85%) were satisfied with the postoperative appearance, 3 patients (7.5%) showed inadequate skin reduction, 1 patient (2.5%) had asymmetry between 2 blepharoplasty lines, and 2 patients (5%) showed obvious scars. CONCLUSIONS: Through a thorough preoperative evaluation, rejuvenation surgery through blepharoplasty incision is an effective solution for mild to moderate upper eyelid sagging in older Asian patients.

Gender, Racial and Ethnic Differences in Pathologic Response Following Neoadjuvant Chemotherapy for Bladder Cancer Patients.

OBJECTIVE: To evaluate trends and racial variations of pathologic complete response (CR) in patients with muscle-invasive bladder cancer undergoing cystectomy. MATERIALS AND METHODS: The National Cancer Database was queried for patients with non-metastatic muscle-invasive bladder cancer who underwent neoadjuvant chemotherapy and surgery. The primary endpoints, CR and mortality, were evaluated using the Cochran-Armitage test, multivariable regression, and Kaplan-Meier analyses. RESULTS: The cohort comprised 9955 patients. Non-Hispanic Black (NHB) patients were younger (P < .001), had a higher clinical tumor (P < .001), and had higher clinical node (P = .029) stages at presentation. CR for non-Hispanic White (NHW), NHB, and Hispanic patients were 12.6%, 10.1%, and 11.8%, respectively (P = .030). There was a significant increase in CR trends for NHW patients (P < .001) and increases in NHB (P = .311) and Hispanic patients (P = .236). On multivariable analysis, NHW females had lower odds of achieving CR (odds ratio: 0.83, 95% CI: 0.71-0.97); however, NHB males (hazard ratio: 1.21, 1.01-1.44) and NHB females (hazard ratio: 1.25, 1.03-1.53) had higher overall mortality in adjusted analysis. Survival differences were not observed in patients who achieved CR, regardless of racial background; however, for those with residual disease, the 2-year survival probabilities were 60.7%, 62.5%, and 51.1% for NHW, HW, and NHB patients, respectively (log-rank P = .010). CONCLUSION: Our findings revealed differences in chemotherapy response based on gender and race or ethnicity. The CR trends for all racial or ethnic groups increased over time. However, Black patients were found to have worse survival, particularly when residual disease was present. Clinical studies with more underrepresented minorities are needed to verify biological differences in response to neoadjuvant chemotherapy.

Gemcitabine as first-line therapy for high-grade non-muscle invasive bladder cancer: results from a tertiary center in the contemporary BCG-shortage era.

Background: To evaluate the safety profile and efficacy of intravesical gemcitabine as first-line adjuvant therapy for non-muscle invasive bladder cancer (NMIBC) in the setting of ongoing Bacillus Calmette-Guérin (BCG) shortage. Methods: We performed an institutional, retrospective review of patients treated with intravesical gemcitabine induction and maintenance therapy from March 2019 to October 2021. Patients with intermediate or high-risk NMIBC who were BCG-naïve or experienced a high-grade (HG) recurrence after 12 months since the last dose of BCG were included in the analysis. The primary endpoint was complete response (CR) rate at the 3-month visit. Secondary endpoints were recurrence-free survival (RFS) and assessment of adverse events. Results: A total of 33 patients were included. All had HG disease and 28 (84.8%) were BCG-naive. The median follow-up was 21.4 months (range, 4.1-39.4). Tumor stages were cTa in 39.4%, cT1 in 54.5%, and cTis in 6.1% of patients. Most patients (90.9%) were in the AUA high-risk category. The 3-month CR was 84.8%. Among patients who achieved CR with adequate follow-up, 86.9% (20/23) remained disease-free at 6 months. The 6-month and 12-month RFS were 87.2% and 76.5%, respectively. The estimated median RFS was not reached. Approximately 78.8% of patients were able to complete full induction. Common adverse events (incidence ≥10%) included dysuria and fatigue/myalgia. Conclusions: Intravesical gemcitabine for intermediate and high-risk NMIBC in areas where BCG supply is limited was safe and feasible at short-term follow-up. Larger prospective studies are needed to better ascertain the oncologic efficacy of gemcitabine.

High-fat diet plus HNF1A variant promotes polyps by activating ß-catenin in early-onset colorectal cancer.

The incidence of early-onset colorectal cancer (EO-CRC) is rising and is poorly understood. Lifestyle factors and altered genetic background possibly contribute. Here, we performed targeted exon sequencing of archived leukocyte DNA from 158 EO-CRC participants, which identified a missense mutation at p.A98V within the proximal DNA binding domain of Hepatic Nuclear Factor 1 α (HNF1AA98V, rs1800574). The HNF1AA98V exhibited reduced DNA binding. To test function, the HNF1A variant was introduced into the mouse genome by CRISPR/Cas9, and the mice were placed on either a high-fat diet (HFD) or high-sugar diet (HSD). Only 1% of the HNF1A mutant mice developed polyps on normal chow; however, 19% and 3% developed polyps on the HFD and HSD, respectively. RNA-Seq revealed an increase in metabolic, immune, lipid biogenesis genes, and Wnt/ß-catenin signaling components in the HNF1A mutant relative to the WT mice. Mouse polyps and colon cancers from participants carrying the HNF1AA98V variant exhibited reduced CDX2 and elevated ß-catenin proteins. We further demonstrated decreased occupancy of HNF1AA98V at the Cdx2 locus and reduced Cdx2 promoter activity compared with WT HNF1A. Collectively, our study shows that the HNF1AA98V variant plus a HFD promotes the formation of colonic polyps by activating ß-catenin via decreasing Cdx2 expression.

Helicobacter pylori CagA inhibits the expression of Runx3 via Src/MEK/ERK and p38 MAPK pathways in gastric epithelial cell.

Infection with CagA-positive Helicobacter pylori is the strongest risk factor for gastric carcinoma. Upon delivery into gastric epithelial cells, CagA disturbs cellular functions by physically interacting with and deregulating intracellular signaling molecules via both tyrosine phosphorylation-dependent and -independent mechanisms. Runx3 was suggested to be a tumor suppressor and closely associated with tumorigenesis and progression of gastric cancer. The aim of our study is to verify the effect of H. pylori virulence factor CagA on Runx3 expression level and investigate the corresponding molecular mechanisms and signaling pathways influencing Runx3 expression. Human gastric epithelial immortalized GES-1 cells were transfected with CagA-expression vector or control vector with FuGENE HD transfection reagent. Runx3 expression levels were determined by QRT-PCR and immunoblotting. Then we constructed a 1,150 bp Runx3 promoter luciferase reporter plasmid, pGL(3)-1150 bp, which was co-transfected into GES-1 cell with CagA-expression vector or control vector. Luciferase reporter assay was used to determine the effects of CagA on the 1,150 bp promoter activity of Runx3. Signal inhibitors were used to detect the signal pathway(s) through which CagA affects Runx3. Our results showed that CagA can reduce the expression level of Runx3 at both mRNA and protein levels significantly. Importantly, the 1,150 bp Runx3 promoter activity was decreased in cells transfected with CagA-expression vector comparing with cells transfected with control vector. And this inhibition is dependent on the phosphorylation of CagA. Signal pathways Src/MEK/ERK and p38 MAPK are involved in this regulation. Our findings provide new insights for understanding the mechanism of H. pylori carcinogenesis.

Proteomic analysis of the function of spot in Helicobacter pylori anti-oxidative stress in vitro and colonization in vivo.

As a microaerobe, Helicobacter pylori employs the global regulator SpoT for defending against oxidative stress in vitro. However, the mechanisms how SpoT affects bacterial gene expression is still unknown. Moreover, the function of SpoT in H. pylori colonization in the host is remaining undetermined. To explore the functions of the SpoT in H. pylori pathogenesis, we constructed H. pylori 26695 spoT-deficient mutant (ΔspoT). While grown in ambient atmosphere, protein expression profile of the ΔspoT was analyzed with 2D gel electrophoresis and real-time PCR. Compared to the wild type, the spoT-deficient strain downregulated its transcription of the oxidative-induced genes, as well as the genes responsible for protein degradation and that related to energy metabolism. Meanwhile, the colonization ability of ΔspoT strains in Mongolian gerbil was tested, the results demonstrated a decayed colonization in the mouse stomach with ΔspoT than the wild type. As a matter of facts, the AGS cells infected with the ΔspoT strains excreted increased level of the gastric inflammation cytokines IL-8, and the ΔspoT strains showed poor survival ability when treated with reactive oxygen stress (sodium nitroprusside). The elevated capacity of stimulating cytokines and fragility to reactive oxygen stress may be contribute to decreased colonization of the spoT-deficient mutant in the mouse stomach. Conclusively, we speculate that spoT is a key regulator of the genes for H. pylori spreading in the air and colonization in host stomach.

The tumor suppressive role of miRNA-370 by targeting FoxM1 in acute myeloid leukemia.

BACKGROUND: Recent evidence has accumulated that MicroRNA (miRNA) dysregulation occurs in the majority of human malignancies including acute myeloid leukemia (AML) and may contribute to onco-/leukemo-genesis. METHODS: The expression levels of miR-370 and FoxM1 were assessed in 48 newly diagnosed AML patients, 40 AML patients in 1st complete remission (CR) and 21 healthy controls. Quantitative real-time PCR, western blots, colony formation assay, and ß-Galactosidase ( SA-ß-Gal) staining were used to characterize the changes induced by overexpression or inhibition of miR-370 or FoxM1. RESULTS: We found that the down-regulation of miR-370 expression was a frequent event in both leukemia cell lines and primary leukemic cells from patients with de novo AML. Lower levels of miR-370 expression were found in 37 of 48 leukemic samples from AML patients compared to those in bone marrow cells derived from healthy adult individuals. Ectopic expression of miR-370 in HL60 and K562 cells led to cell growth arrest and senescence. In contrast, depletion of miR-370 expression using RNA interference enhanced the proliferation of those leukemic cells. Mechanistically, miR-370 targets the transcription factor FoxM1, a well established oncogenic factor promoting cell cycle progression. Moreover, when HL60 and K562 cells were treated with 5-aza-2'-deoxycytidine, a DNA methylation inhibitor, miR-370 expression was up-regulated, which indicates epigenetic silencing of miR-370 in leukemic cells. CONCLUSIONS: Taken together, miR-370 may function as a tumor suppressor by targeting FoxM1, and the epigenetic silence of miR-370 thus leads to derepression of FoxM1 expression and consequently contributes to AML development and progression.

How Do Blended Biochemistry Classes Influence Students' Academic Performance and Perceptions of Self-Cognition?

The flipped classroom is becoming a popular new instructional model in higher education capable of increasing student performance in higher-order learning outcomes. However, the success of a flipped classroom model depends on various supporting elements, and it may not be appropriate for all students and courses. In this study, a new blended Biochemistry classroom model based on Massive Open Online Courses (MOOC) and a "semi-flipped" environment was applied to Biochemistry instruction of Nursing and Clinical Medicine majors. The students' academic performance and perceptions of self-cognition were used to assess the blended Biochemistry classroom. Students who participated in the blended classroom model achieved higher academic performance (p < 0.01) and reported a significant improvement in their perceptions of self-cognition (p < 0.05) compared to the control group. Moreover, the effectiveness of the blended Biochemistry classroom on the small size class (Nursing major) was stronger than on the large size class (Clinical Medicine major).

Assessment of blended biochemistry classes based on massive open online courses and a "semi-flipped" learning environment.

Flipped classroom based on active learning is becoming an increasingly popular pedagogical method in higher education capable of increasing student performance in higher-order learning outcomes including application, analysis, evaluation, and creation. However, the success of a flipped classroom model relies on various supporting elements such as the accessibility of technology, and it may not be appropriate for all students and courses. In this study, a new blended biochemistry classroom model based on massive open online courses and a "semi-flipped" environment was applied to the students enrolled in three majors (stomatology, pharmacy, and preventive medicine) at Cheeloo College of Medicine, Shandong University, China. To assess the improvement of the students' perception of self-cognition in the blended biochemistry classes, surveys were conducted before and after undertaking the biochemistry course. Survey responses and total (final) score for the biochemistry course were analyzed using appropriate statistical methods. Compared to students who received traditional classroom instruction, students who participated in the blended classroom model achieved higher academic performance (p < 0.01) and reported a significant improvement in their perception of self-cognition (p < 0.01, or p < 0.05). More than 80% of participants preferred the blended classroom model to that of traditional classroom instruction.

Symptom Resolution and Recurrent Urinary Incontinence Following Removal of Painful Midurethral Slings.

OBJECTIVE: To evaluate pain improvement and recurrent stress incontinence (SUI) following painful synthetic midurethral sling (MUS) removal. METHODS: We conducted a retrospective review of patients who underwent synthetic MUS removal at our institution from 2009-2016 for the indication of pain. We recorded sling type (transobturator vs retropubic), complete vs partial removal, and presenting symptoms. Postoperative pain improvement was categorized as resolved (pain resolved, requiring no further therapy), improved (pain less bothersome, may require further therapy), or unresolved (no/minimal improvement, requiring further management). Recurrent incontinence and further reconstructive procedures were assessed. RESULTS: 87 patients (49 complete and 38 partial removal) with pain as the primary indication for removal were included. Median age at intervention was 54 years with median follow-up of 8 months. Overall, pain improved or resolved in 78.1% of cases. Complete removal was associated with significantly greater percentage of pain resolution (63.3%) compared to partial removal (26.3%) (P = 0.002) regardless of sling type. No significant differences in recurrent SUI were noted in complete vs partial removal. Additional reconstructive procedures were performed in 28 patients, most commonly sling placement, with no significant difference in complete (20.4%) vs partial (28.9%) removal groups (P = 0.36). The overall complication rate was low (5.7%), a majority of which were transfusions (4.6%). CONCLUSION: Following MUS removal, most patients experienced resolution or improvement of pain. Complete sling removal was associated with significantly greater percentage of pain resolution compared to partial removal in both retropubic and transobturator slings. Rates of recurrent SUI and reintervention for SUI were not related to the extent of sling removal.

Wnt/beta-catenin signaling confers ferroptosis resistance by targeting GPX4 in gastric cancer.

The development of chemotherapy resistance is the most vital obstacle to clinical efficacy in gastric cancer (GC). The dysregulation of the Wnt/beta-catenin signaling pathway is critically associated with GC development and chemotherapy resistance. Ferroptosis is a form of regulated cell death, induced by an iron-dependent accumulation of lipid peroxides during chemotherapy. However, whether the Wnt/beta-catenin signaling directly controls resistance to cell death, remains unclear. Here, we show that the activation of the Wnt/beta-catenin signaling attenuates cellular lipid ROS production and subsequently inhibits ferroptosis in GC cells. The beta-catenin/TCF4 transcription complex directly binds to the promoter region of GPX4 and induces its expression, resulting in the suppression of ferroptotic cell death. Concordantly, TCF4 deficiency promotes cisplatin-induced ferroptosis in vitro and in vivo. Thus, we demonstrate that the aberrant activation of the Wnt/beta-catenin signaling confers ferroptosis resistance and suggests a potential therapeutic strategy to enhance chemo-sensitivity for advanced GC patients.

The histone demethylase RBP2 Is overexpressed in gastric cancer and its inhibition triggers senescence of cancer cells.

BACKGROUND & AIMS: The aberrant expression of histone-modifying enzymes such as histone deacetylases contributes to oncogenesis. It is unclear whether RBP2, a newly identified histone demethylase, is involved in cancer development/progression. We determined RBP2 expression in gastric cancer and its biologic function in cancer cells. METHODS: Cancerous and matched normal gastric specimens from 42 patients with gastric cancer were analyzed for RBP2 expression using quantitative real-time polymerase chain reaction and immunohistochemistry. Gene expression was assessed using quantitative real-time polymerase chain reaction and immunoblotting and depleted with small interference RNA. Clonogenesis and cellular senescence were examined by foci formation and beta-Galactosidase staining. Promoter activity was determined by luciferase reporter assay. Chromatin immunoprecipitation was used to detect RBP2 and methylated histone H3-K4 on promoters. RESULTS: RBP2 messenger RNA and protein expression were increased in 71.5% (30/42) and 100% (20/20) of gastric cancer specimens, respectively. Significantly diminished foci numbers coupled with massive senescence/growth arrest and elevated expression of cyclin-dependent kinase inhibitors (CDKIs) p21(CIP1), p27(kip1), and/or p16(ink4a) occurred in RBP2-depleted gastric and cervical cancer cells. RBP2 depletion-mediated senescence and clonogenic defect were attenuated by inhibiting p21(CIP1) or p27(kip1) expression. The promoter activity of all 3 CDKIs genes was enhanced by RBP2 inhibition. RBP2 occupied these promoters in control cells, and the loss of RBP2 occupancy was accompanied by enhanced H3-K4 trimethylation following RBP2 depletion. CONCLUSIONS: RBP2 is overexpressed in gastric cancer, and its inhibition triggers senescence of malignant cells at least partially by derepressing its target genes CDKIs. Histone demethylase inhibition by targeting RBP2 may be an anticancer strategy.