Induction of apoptosis by VB1 in breast cancer cells: the role of reactive oxygen species and Bcl-2 family proteins

Vitexin Glucolone Reinforces Radiosensitivity of Non-Small Cell Lung Cancer via Transforming Growth Factor Kinase 1/Adenylate Activated Protein Kinase Signaling Pathway

Purpose: To discuss effects of vitexin glucolone (VG) to radiosensitivity of NSCLC (Non-small cell lung cancer) cell lines (A549 and H1299). Methods: Treating A549 and H1299 cells by VG with or without X-radiation. Cell viability was calculated by CCK8. Apoptosis rate was measured by flow cytometry and Western blot to expressions of protein. Subsequently, cells were transferred with TAK1 siRNA, cell viability and apoptosis were measured. Results: VG decreased the viability of Huh7 cells and inhibited effects of VG was more strengthen than radiotherapy in concentrations of 20 μmol/L and 40 μmol/L. Meanwhile, VG sensitized HCC exposed to radiation therapy to apoptosis as demonstrated by increased Bax/Bcl-2 ratio. In addition, VG enhanced the promotive effects of X-radiation on the expressions of TAK1, AMPKα1 and PPARγ. Furthermore, silence the expression of TAK1 partly reversed the effects of VG on HCC and radiosensitivity of NSCLC. Conclusion: VG enhances radiosensitivity of NSCLC via TAK1/AMPK pathway.

Purified Vitexin Compound 1 Inhibits UVA-Induced Cellular Senescence in Human Dermal Fibroblasts by Binding Mitogen-Activated Protein Kinase 1

Purified vitexin compound 1 (VB1), a novel lignanoid isolated from the seeds of the Chinese herb Vitex negundo, has strong antioxidant abilities and broad antitumor activities. However, little is known about its anti-photoaging effect on the skin and the underlying mechanism. Here, we demonstrated that VB1 significantly attenuates ultraviolet A (UVA)-induced senescence in human dermal fibroblasts (HDFs), as evidenced by senescence-associated β-gal staining, MTT assays, and western blot analysis of the expression of p16 and matrix metalloproteinase-1 (MMP-1). Furthermore, mass spectrometry revealed that VB1 could directly bind to Mitogen-Activated Protein Kinase 1 (MAPK1). Molecular docking and molecular dynamics simulation methods confirmed the mass spectroscopy results and predicted six possible binding amino acids of MAPK1 that most likely interacted with VB1. Subsequent immunoprecipitation analysis, including different MAPK1 mutants, revealed that VB1 directly interacted with the residues, glutamic acid 58 (E58) and arginine 65 (R65) of MAPK1, leading to the partial reversal of UVA-induced senescence in HEK293T cells. Finally, we demonstrated that the topical application of VB1 to the skin of mice significantly reduced photoaging phenotypes in vivo. Collectively, these data demonstrated that VB1 reduces UVA-induced senescence by targeting MAPK1 and alleviates skin photoaging in mice, suggesting that VB1 may be applicable for the prevention and treatment of skin photoaging.

Modulation of MnSOD and FoxM1 Is Involved in Invasion and EMT Suppression by Isovitexin in Hepatocellular Carcinoma Cells

Background

Manganese superoxide dismutase (MnSOD) induces FoxM1 expression, subsequently contributing to migration in several cancer cells. Isovitexin (ISOV) was recently found to downregulate MnSOD and FoxM1, decreasing stemness in hepatocellular carcinoma (HCC) stem-like cells (HCSLCs). The current study aimed to determine whether inhibition of migration, invasion and EMT in HCSLCs by ISOV results from MnSOD/FoxM1 signaling blockade and subsequent Twist1, Slug, ZEB1 and MMP-2 downregulation.

Materials and Methods

We examined the migratory and invasive capabilities and EMT phenotype in HCC cells and their HCSLCs, respectively, by wound-healing assay, transwell invasion assay and Western blot after treatment with non-cytotoxic concentrations of ISOV, and explored the mechanism by which ISOV affects migration, invasion and EMT by MnSOD or FoxM1 knockdown and/or overexpression in HCSLCs or HCC cells.

Results

The results showed that ISOV not only downregulated MnSOD and FoxM1 but also suppressed the migratory and invasive capabilities and reversed the EMT phenotype in HCSLCs, which was reflected by elevated E-cadherin protein amounts, and reduced N-cadherin, Twist1, Slug, ZEB1 and MMP-2 protein levels. The suppressive effects of ISOV on the migratory and invasive capabilities and EMT phenotype could be potentiated by MnSOD or FoxM1 knockdown in HCSLCs, and attenuated by MnSOD or FoxM1 overexpression in HCC cells. Importantly, FoxM1 overexpression reversed MnSOD knockdown combined with ISOV suppression on the migratory and invasive capabilities and EMT phenotype in HCSLCs, while having little effects on MnSOD expression.

Conclusion

Collectively, the above findings demonstrated that ISOV suppresses migration, invasion and EMT in HCSLCs by blocking MnSOD/FoxM1 signaling subsequently inhibiting the expression of EMT-related transcription factors and MMP-2.

PDIA4: The basic characteristics, functions and its potential connection with cancer

Disulfide bond formation is catalyzed by the protein disulfide Isomerases (PDI) family. This is a critical step in protein folding which occurs within the endoplasmic reticulum. PDIA4, as a member of the PDI family, can cause the adjustment of αIIβ 3 affinities which activate platelet and promote thrombosis formation. Endoplasmic reticulum response is triggered by accumulation of abnormal folding proteins concomitant with increasing PDIA4 expression. Besides, current researches indicate that activated platelets and ERS response affect tumor progression. And PDIA4, as previous reported, also participates in tumor progression by affecting cell apoptosis and DNA repair machinery without specific mechanisms revealed.Therefore, PDI inhibitor might possess great potential value in against tumor progression. In this review, we summarize information on PDIA4 including its the basic characteristics and its implication on tumor.

Purified vitexin compound 1, a new neolignan isolated compound, promotes PUMA-dependent apoptosis in colorectal cancer

Purified vitexin compound 1 (VB1, a neolignan isolated and extracted from the seed of Chinese herb Vitex negundo) is an effective antitumor agent and exhibits promising clinical activity against various cancers including colorectal cancer. However, it remains unknown about the precise underlying mechanism associated with the antitumor effect of VB1 and how it triggers apoptosis in cancer cells. Here, we demonstrated that VB1 promoted apoptosis via p53-dependent induction of p53 upregulated modulator of apoptosis (PUMA) and further to induce Bax (Bcl-2-associated X protein) activation and mitochondrial dysfunction in colon cancer HCT-116 and LoVo cells. Deficiency in p53, PUMA, or Bax abrogated VB1-induced apoptosis and promoted cell survival in HCT-116 cells. Furthermore, the combination of VB1 with chemotherapeutic drugs 5-fluorouracil (5-FU) or NVP-BZE235 resulted in a synergistic antitumor effect via PUMA induction in HCT-116 cells. VB1 significantly suppressed the cell proliferation of wild-type (WT) HCT-116 and LoVo cells in vitro and tumor growth in vivo. The results indicate that p53/PUMA/Bax axis plays a critical role in VB1-induced apoptosis and VB1 may have valuable clinical applications in cancer therapy as a novel anticancer agent used alone or in combination with other chemotherapeutic drugs.