ABSTRACT
Hypoxia-inducible factor 1α (HIF-1α) is a known regulator of tumor cell proliferation, migration, and angiogenesis. The presence of a high concentration of HIF-1α is positively correlated with the severity of cancer. Therefore, the inhibition of this pathway represents an important therapeutic target for the treatment of various types of cancer. Here, we designed and synthesized 30 panaxadiol (PD) derivatives and evaluated their inhibitory activities against HIF-1α transcription. Of these, compound 3l exhibited the most promising inhibitory activity (IC50 = 3.7 µM) and showed significantly decreased cytotoxicity compared with PD. Compound 9e exhibited the strongest cytotoxic effect and may be considered for further preclinical development.
Subject(s)
Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Ginsenosides/chemistry , Ginsenosides/pharmacology , Hypoxia-Inducible Factor 1, alpha Subunit/antagonists & inhibitors , Antineoplastic Agents/chemical synthesis , Cell Line, Tumor , Ginsenosides/chemical synthesis , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Neoplasms/drug therapy , Neoplasms/genetics , Structure-Activity Relationship , Transcriptional Activation/drug effectsABSTRACT
Hypoxia promotes tumor invasion and metastasis via multiple mechanisms, including epithelial-mesenchymal transition (EMT). Twist, an EMT regulator, has been disclosed to associate with invasion and metastasis as well as poor prognosis of many malignancies. However, it remains undefined whether Twist is involved in invasion and metastasis of hypoxic non-small cell lung cancer (NSCLC). In this study, protein levels of Twist, hypoxia-inducible factor-1α (HIF-1α), and EMT markers (E-cadherin and vimentin) were examined by immunohistochemistry in 76 lung cancer tissues from NSCLC patients. Expression of Twist and its correlation with HIF-1α, E-cadherin, and vimentin were analyzed. Small interfering RNA (siRNA) against Twist was used to knockdown Twist expression in hypoxic NSCLC cells, A549 and NCI-H460. Cellular invasion and protein levels of Twist, E-cadherin, and vimentin were evaluated by matrigel invasion assay and Western blot, respectively. Our results showed that in clinical samples, there was a significant association between Twist expression and differentiation degree, lymph node metastasis, and TNM stage. Correlation analysis demonstrated that expression of Twist was negatively correlated with E-cadherin expression, but positively associated with HIF-1α and vimentin expression. In cultured NSCLC cells, Twist messenger RNA (mRNA) and protein levels were upregulated under hypoxia, while knockdown of Twist suppressed potentiated invasion and expression of mesenchymal marker vimentin induced by hypoxia. Protein level of increased epithelial marker E-cadherin was shown along with Twist downregulation. These findings suggest that Twist promoting hypoxic invasion and metastasis of NSCLC may be associated with altered expression of EMT markers. Inhibition of Twist may be of therapeutic significance.
Subject(s)
Adenocarcinoma/secondary , Biomarkers, Tumor/metabolism , Carcinoma, Non-Small-Cell Lung/secondary , Carcinoma, Squamous Cell/secondary , Hypoxia/pathology , Lung Neoplasms/pathology , Nuclear Proteins/metabolism , Twist-Related Protein 1/metabolism , Adenocarcinoma/genetics , Adenocarcinoma/metabolism , Adult , Aged , Antigens, CD , Apoptosis , Biomarkers, Tumor/genetics , Blotting, Western , Cadherins/genetics , Cadherins/metabolism , Carcinoma, Non-Small-Cell Lung/genetics , Carcinoma, Non-Small-Cell Lung/metabolism , Carcinoma, Squamous Cell/genetics , Carcinoma, Squamous Cell/metabolism , Cell Movement , Cell Proliferation , Female , Follow-Up Studies , Humans , Hypoxia/genetics , Hypoxia/metabolism , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Immunoenzyme Techniques , Lung Neoplasms/genetics , Lung Neoplasms/metabolism , Lymphatic Metastasis , Male , Middle Aged , Neoplasm Invasiveness , Neoplasm Staging , Nuclear Proteins/antagonists & inhibitors , Nuclear Proteins/genetics , Prognosis , RNA, Messenger/genetics , RNA, Small Interfering/genetics , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , Tumor Cells, Cultured , Twist-Related Protein 1/antagonists & inhibitors , Twist-Related Protein 1/genetics , Vimentin/genetics , Vimentin/metabolismABSTRACT
Mediator 19 (Med19) is a component of the mediator complex which is a coactivator for DNA-binding factors that activate transcription via RNA polymerase II. Accumulating evidence has shown that Med19 plays important roles in cancer cell proliferation and tumorigenesis. The involvement of Med19 in sensitivity to the chemotherapeutic agent cisplatin was here investigated. We employed RNA interference to reduce Med19 expression in human non-small cell lung cancer (NSCLC) cell lines and analyzed their phenotypic changes. The results showed that after Med19 siRNA transfection, expression of Med19 mRNA and protein was dramatically reduced (p<0.05). Meanwhile, impaired growth potential, arrested cell cycle at G0/G1 phase and enhanced sensitivity to cisplatin were exhibited. Apoptosis and caspase-3 activity were increased when cells were exposed to Med19 siRNA and/or cisplatin. The present findings suggest that Med19 facilitates tumorigenic properties of NSCLC cells and knockdown of Med19 may be a rational therapeutic tool for lung cancer cisplatin sensitization.
Subject(s)
Carcinoma, Non-Small-Cell Lung/drug therapy , Cell Proliferation/drug effects , Cisplatin/pharmacology , Drug Resistance, Neoplasm/genetics , Lung Neoplasms/drug therapy , Mediator Complex/antagonists & inhibitors , Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Blotting, Western , Carcinoma, Non-Small-Cell Lung/genetics , Carcinoma, Non-Small-Cell Lung/pathology , Cell Cycle/drug effects , Flow Cytometry , Humans , Immunoenzyme Techniques , Lung Neoplasms/genetics , Lung Neoplasms/pathology , Mediator Complex/genetics , Mediator Complex/metabolism , RNA, Messenger/genetics , RNA, Small Interfering/genetics , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , Tumor Cells, CulturedABSTRACT
Lysyl oxidase (LOX), a copper-dependent amine oxidase known to function both intracellularly and extracellularly, is implicated in promoting tumor progression and hypoxic metastasis in certain malignancies. Nonsmall cell lung cancer (NSCLC) is a highly aggressive cancer with poor prognosis worldwide. However, the role and molecular mechanism by which LOX involving in hypoxic NSCLC invasion and migration are poorly understood. This study explores the effect of LOX on invasion and migration of NSCLC cells under hypoxic conditions. Small interfering RNA (siRNA) targeting LOX was used to silence LOX expression of hypoxic NSCLC cells, SPCA1 and A549. Cellular invasive and migratory potentials were determined by matrigel invasion and migration assays. Expression of LOX, Src, Src activation (Tyr418 phosphorylation of Src), and Snail were evaluated by real-time PCR and western blot, respectively. The results showed that LOX mRNA and protein expression were upregulated under hypoxic conditions in NSCLC cells. Knockdown of LOX led to inhibition of hypoxia-induced invasion and migration. Phosphorylated Src (Tyr418) and Snail proteins were decreased along with LOX downregulation. Our data provide molecular evidences that LOX is mechanistically linked to increased invasion and migration of hypoxic NSCLC cells, and may serve as an antimetastasis target of human NSCLC.
