Romidepsin and Tamoxifen Cooperatively Induce Senescence of Pancreatic Cancer Cells Through Downregulation of FOXM1 Expression and Induction of ROS/Lipid Peroxidation

Although progress has been made in chemotherapeutic strategies against pancreatic cancer, overall survival has not significantly improved over the past decade. Thus, the development of better therapeutic regimens remains a high priority. Pancreatic cancer cell lines were treated with romidepsin, an inhibitor of histone deacetylase, and tamoxifen, and their effects on cell growth, signaling and gene expression were determined. Xenografts of human pancreatic cancer CFPAC1 cells were treated with romidepsin and tamoxifen to determine their effects on tumor growth. The inhibition of the growth of pancreatic cancer cells induced by romidepsin and tamoxifen was effectively reduced by N-acetyl cysteine and α-tocopherol, respectively. The combined treatment greatly induced reactive oxygen species production and mitochondrial lipid peroxidation, and these effects were prevented by N-acetyl cysteine and α-tocopherol. Tamoxifen enhanced romidepsin-induced cell senescence. FOXM1 expression was markedly downregulated in pancreatic cancer cells treated with romidepsin, and tamoxifen further reduced FOXM1 expression in cells treated with romidepsin. Siomycin A, an inhibitor of FOXM1, induced senescence in pancreatic cancer cells. Similar results were obtained in knockdown of FOXM1 expression by siRNA. Since FOXM1 is used as a prognostic marker and therapeutic target for pancreatic cancer, a combination of the clinically available drugs romidepsin and tamoxifen might be considered for the treatment of patients with pancreatic cancer.

ANGI-1 Impact of neoadjuvant bevacizumab on transcriptional factor for stemness, macrophage polarization, and oxygenation of tumor microenvironment in glioblastoma

Background: Previously we reported that bevacizumab (Bev) produces tumor oxygenation with immunosupportive tumor microenvironment (TME) and inhibition of stemness. To confirm whether those effects might contribute prolongation of clinical outcome, in the present study paired samples from same patients with newly diagnosed GBM who received Bev during its effectiveness and refractoriness were investigated by immunohistochemistry. Methods: Eighteen samples from 9 patients with newly diagnosed GBM who received preoperative neoadjuvant Bev (neoBev) followed by surgical operation and chemoradiotherapy in addition to salvage surgery after recurrence were investigated. Expressions of FOXM1, HIF-1, and CD163 were evaluated by immunohistochemistry. Overall survial (OS) were analyzed with the present cohort divided into two groups between good and poor responder (GR and PR, respectively) of Bev defined as tumor regression rate judged by T1 gadolinium enhancement (T1Gd) and fluid attenuated inversion recovery (FLAIR) images. Results: In the group of good responder of T1Gd (T1Gd-GR; defined as >38% of regression rate after neoBev), OS was prolonged compared with T1Gd-PR along with inhibition of FOXM1 expression and HIF-1a. In contrast, in the group of good responder of FLAIR (FLAIR-GR; defined as >54% of regression rate after neoBev), there were no significant differences of OS and FOXM1 expression between GR and PR. HIF-1a expression tended to be elevated in T1Gd-PR of initial tumors, T1Gd-GR of recurrent tumors, and FLAIR-PR of both initial and recurrent tumors.Conclusion: T1Gd-GR after neoBev might attribute to inhibition of FOXM1 and oxygenation. Bev might provide tumor oxygenation, leading to inhibition of stemness and M2 TAM infiltration during its effectiveness. These results suggested that Bev combined with immunotherapy for newly diagnosed GBM might provide clinical benefits including inhibition of stemness and induction of immunosupportive TME, when tumor volume assessed by T1 Gd. was significantly decreased following neoBev.

NOX4-derived ROS-induced overexpression of FOXM1 regulates aerobic glycolysis in glioblastoma

Background Increased expression of the transcription factor Forkhead box M1 (FOXM1) has been reported to play an important role in the progression and development of multiple tumors, but the molecular mechanisms that regulate FOXM1 expression remain unknown, and the role of FOXM1 in aerobic glycolysis is still not clear. Methods The expression of FOXM1 and NADPH oxidase 4 (NOX4) in normal brain tissues and glioma was detected in data from the TCGA database and in our specimens. The effect of NOX4 on the expression of FOXM1 was determined by Western blot, qPCR, reactive oxygen species (ROS) production assays, and luciferase assays. The functions of NOX4 and FOXM1 in aerobic glycolysis in glioblastoma cells were determined by a series of experiments, such as Western blot, extracellular acidification rate (ECAR), lactate production, and intracellular ATP level assays. A xenograft mouse model was established to test our findings in vivo. Results The expression of FOXM1 and NOX4 was increased in glioma specimens compared with normal brain tissues and correlated with poor clinical outcomes. Aberrant mitochondrial reactive oxygen species (ROS) generation of NOX4 induced FOXM1 expression. Mechanistic studies demonstrated that NOX4-derived MitoROS exert their regulatory role on FOXM1 by mediating hypoxia-inducible factor 1α (HIF-1α) stabilization. Further research showed that NOX4-derived MitoROS-induced HIF-1α directly activates the transcription of FOXM1 and results in increased FOXM1 expression. Overexpression of NOX4 or FOXM1 promoted aerobic glycolysis, whereas knockdown of NOX4 or FOXM1 significantly suppressed aerobic glycolysis, in glioblastoma cells. NOX4-induced aerobic glycolysis was dependent on elevated FOXM1 expression, as FOXM1 knockdown abolished NOX4-induced aerobic glycolysis in glioblastoma cells both in vitro and in vivo. Conclusion Increased expression of FOXM1 induced by NOX4-derived MitoROS plays a pivotal role in aerobic glycolysis, and our findings suggest that inhibition of NOX4-FOXM1 signaling may present a potential therapeutic target for glioblastoma treatment.

Cardamonin Promotes the Apoptosis and Chemotherapy Sensitivity to Gemcitabine of Pancreatic Cancer Through Modulating the FOXO3a-FOXM1 Axis

Cardamonin (CAR), a flavone existing in the Alpinia plant, has been found to modulate multiple biological activities, including antioxidant, anti-inflammatory, and anti-tumor effects. Nevertheless, the influence of CAR on pancreatic cancer (PC) is less understood. Here, we conducted in vitro and in vivo experiments to explore the functions of CAR on PC cells’ proliferation, apoptosis and chemosensitivity to gemcitabine (GEM). The growth of PC cells (including PANC-1 and SW1990) was evaluated by the cell counting kit-8 assay, colony formation assay and xenograft tumor experiment. Besides, the apoptosis was determined by flow cytometry and western blot (WB). Moreover, the FOXO3a-FOXM1 pathway expression was tested by reverse transcription-polymerase chain reaction and WB. Our data suggested that CAR restrained cell proliferation, growth and expedited apoptosis both in vitro and in vivo. Moreover, CAR sensitized PC cells to GEM. Mechanistically, CAR heightened FOXO3a while repressed FOXM1. Further loss-of-function assays revealed that down-regulating FOXO3a markedly dampened the anti-tumor effect induced by CAR and accelerated the FOXM1 expression. Our data confirmed that CAR exerted an anti-tumor function in PC dependently by modulating the FOXO3a-FOXM1 axis.

USP28 facilitates pancreatic cancer progression through activation of Wnt/β-catenin pathway via stabilising FOXM1

Ubiquitination is an important post-translational modification that can be reversed by a family of enzymes called deubiquitinating enzymes (DUBs). Ubiquitin-specific protease 28 (USP28), a member of the DUBs family, functions as a potential tumour promoter in various cancers. However, the biological function and clinical significance of USP28 in pancreatic cancer (PC) are still unclear. Here, we showed that PC tumours had higher USP28 expression compared with that of normal pancreatic tissues, and high USP28 level was significantly correlated with malignant phenotype and shorter survival in patients with PC. Overexpression of USP28 accelerated PC cell growth, whereas USP28 knockdown impaired PC cell growth both in vitro and in vivo. Further, we found that USP28 promoted PC cell growth by facilitating cell cycle progression and inhibiting apoptosis. Mechanistically, USP28 deubiquitinated and stabilised FOXM1, a critical mediator of Wnt/β-catenin signalling. USP28-mediated stabilisation of FOXM1 significantly promoted nucleus β-catenin trans-activation, which in turn led to the activation of the Wnt/β-catenin pathway. Finally, restoration of FOXM1 expression abolished the anti-tumour effects of USP28-silencing. Thus, USP28 contributes to PC pathogenesis through enhancing the FOXM1-mediated Wnt/β-catenin signalling, and could be a potential diagnostic and therapeutic target for PC cases.

LncRNA GACAT3 promotes esophageal squamous cell carcinoma progression through regulation of miR-149/FOXM1

Background The long noncoding RNA gastric cancer associated transcript 3 (GACAT3) has been demonstrated to be implicated in the carcinogenesis and progression of many malignancies. However, GACAT3’s levels and role in esophageal squamous cell carcinoma (ESCC) has not been elucidated. Methods GACAT3 amounts were investigated in ESCC tissues and cell lines by qPCR. Its biological functions were examined by CCK-8 assay, colony formation assay, flow cytometry, wound healing assay, transwell assay, and xenograft model establishment. The relationship between GACAT3 and miR-149 was assessed by dual-luciferase reporter assay. Results GACAT3 amounts were elevated in ESCC tissue and cell specimens. Functional studies showed that GACAT3 silencing reduced the proliferation, migration and invasion of cultured ESCC cells, and decreased tumor growth in mice. Furthermore, GACAT could directly interact with miR-149. In addition, colony formation and invasion assays verified that GACAT3 promotes ESCC tumor progression through miR-149. Moreover, GACAT3 acted as a competing endogenous RNA (ceRNA) to modulate FOXM1 expression. Conclusions These findings indicate that GACAT3 functions as an oncogene by acting as a ceRNA for miR-149 to modulate FOXM1 expression in ESCC, suggesting that GACAT3 might constitute a therapeutic target in ESCC.

Differential expression of forkhead box M1 in human epithelial ovarian cancer.

Epithelial ovarian cancer (EOC) is the most lethal gynecologic cancer (1). We performed discovery of genes associated with epithelial ovarian cancer and of the high-grade serous ovarian cancer (HGSC) subtype, using published microarray data (2, 3) to compare global gene expression profiles of normal ovary or fallopian tube with that of primary tumors from women diagnosed with epithelial ovarian cancer or HGSC. We identified the gene encoding forkhead box M1, FOXM1, as among the genes whose expression was most different in epithelial ovarian cancer as compared to the normal fallopian tube. FOXM1 expression was significantly higher in high-grade serous ovarian tumors relative to normal fallopian tube. FOXM1 expression correlated with progression-free survival in patients with ovarian cancer. These data indicate that expression of FOXM1 is perturbed in epithelial ovarian cancers broadly and in ovarian cancers of the HGSC subtype. FOXM1 may be relevant to pathways underlying ovarian cancer initiation (transformation) or progression.

FOXM1-AKT Positive Regulation Loop Provides Venetoclax Resistance in AML

Forkhead box protein M1 (FOXM1) is a crucial regulator of cancer development and chemoresistance. It is often overexpressed in acute myeloid leukemia (AML) and is associated with poor survival and reduced efficacy of cytarabine therapy. Molecular mechanisms underlying high FOXM1 expression levels in malignant cells are still unclear. Here we demonstrate that AKT and FOXM1 constitute a positive autoregulatory loop in AML cells that sustains high activity of both pro-oncogenic regulators. Inactivation of either AKT or FOXM1 signaling results in disruption of whole loop, coordinated suppression of FOXM1 or AKT, respectively, and similar transcriptomic changes. AML cells with inhibited AKT activity or stable FOXM1 knockdown display increase in HOXA genes expression and BCL2L1 suppression that are associated with prominent sensitization to treatment with Bcl-2 inhibitor venetoclax. Taken together, our data indicate that AKT and FOXM1 in AML cells should not be evaluated as single independent regulators but as two parts of a common FOXM1-AKT positive feedback circuit. We also report for the first time that FOXM1 inactivation can overcome AML venetoclax resistance. Thus, targeting FOXM1-AKT loop may open new possibilities in overcoming AML drug resistance and improving outcomes for AML patients.