5-7-dihydroxy-6-methoxy-2-phenylchromen-4-one and Carcinoma--Non-Small-Cell-Lung

Hypoxia is a key concern during the treatment of non-small cell lung cancer (NSCLC), and hypoxia-inducible factor 1 alpha (HIF-1α) has been associated with increased tumor resistance to therapeutic modalities such as cisplatin. Compensatory activation of nucleotide excision repair (NER) pathway is the major mechanism that accounts for cisplatin resistance. In the present study, we suggest a novel strategy to improve the treatment of NSCLC and overcome the hypoxia-induced cisplatin resistance by cotreatment with Oroxylin A, one of the main bioactive flavonoids of Scutellariae radix. Based on the preliminary screening, we found that xeroderma pigmentosum group C (XPC), an important DNA damage recognition protein involved in NER, dramatically increased in hypoxic condition and contributed to hypoxia-induced cisplatin resistance. Further data suggested that Oroxylin A significantly reversed the hypoxia-induced cisplatin resistance through directly binding to HIF-1α bHLH-PAS domain and blocking its binding to HRE3 transcription factor binding sites on XPC promoter which is important to hypoxia-induced XPC transcription. Taken together, our findings not only demonstrate a crucial role of XPC dependent NER in hypoxia-induced cisplatin resistance, but also suggest a previously unrecognized tumor suppressive mechanism of Oroxylin A in NSCLC which through sensitization of cisplatin-mediated growth inhibition and apoptosis under hypoxia.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Carcinoma, Non-Small-Cell Lung; Cell Hypoxia; Cell Line, Tumor; Cisplatin; DNA Repair; DNA-Binding Proteins; Drug Resistance, Neoplasm; Drug Synergism; Flavonoids; Gene Expression Regulation, Neoplastic; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Lung Neoplasms; Mice; Promoter Regions, Genetic; Transcription, Genetic; Xenograft Model Antitumor Assays

Oroxylin A (OA), a naturally occurring monoflavonoid isolated from Scutellariae radix, has previously been reported to inhibit the proliferation of several cancer cell lines. CD4+CD25+Foxp3+ regulatory T cells (Tregs) play an important role in maintenance of immunologic self-tolerance. Tregs also increase in cancer and take part in suppressing antitumor immune responses. Here, we explored how OA affected the Tregs in lung cancer environment and the involved underlying mechanism. It is found that OA reversed the generation of Tregs induced by H460 lung cancer cells co-culture. Furthermore, in vivo, OA reduced tumor formation rate and attenuated Foxp3 expression in tumor-infiltrating lymphocytes. We also found that transforming growth factor-β1 (TGF-β1) neutralizing antibody reversed the enhancement of Treg number and expression of p-Smad3'p-p38'p-JNK'p-ERK1/2 in the co-culture model. Moreover, OA reduced the secretion of TGF-β1 and down-regulated the activation of NF-κB signaling in H460 cells. OA also inhibited Treg activity by a direct inhibition of the T cells' response to TGF-β1. In conclusion, our study demonstrated that OA inhibits the generation of Tregs in lung cancer environment by inhibiting the T cells' response to TGF-β1 and decreasing the secretion of TGF-β1 in lung cancer cells via NF-κB signaling.

Topics: Animals; Biomarkers; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Coculture Techniques; Disease Models, Animal; Flavonoids; Humans; Immunophenotyping; Jurkat Cells; Leukocytes, Mononuclear; Lung Neoplasms; Mice; NF-kappa B; Signal Transduction; T-Lymphocytes, Regulatory; Transforming Growth Factor beta; Xenograft Model Antitumor Assays

Snail is closely linked to tumor invasion, metastasis, and recurrence and indicates prognosis of patients suffering from cancer. Overexpression of Snail increases motility and invasiveness of cancer cells, which has become target for anti-metastatic treatment. Oroxylin A, a natural compound extracted from Scutellaria radix, has been reported to inhibit invasion and migration in breast cancer. In this study, we investigated the anti-invasive effect of oroxylin A on lung cells and uncovered its underlying mechanism. The results suggested that oroxylin A could inhibit migration and invasion in Snail-expressing 95-D, and A549 cells whereas it had little effect on non-expressing GLC-82 cells. Furthermore, enhanced Snail expression after transfection of Snail vector in GLC-82 cells is decreased by oroxylin A. Snail can also induce epithelial-mesenchymal transition. We found oroxylin A could reverse TGFβ1-induced epithelial-mesenchymal transition by inhibiting Snail expression. As a result, oroxylin A up-regulated E-cadherin expression and down-regulated vimentin, MMP-9, and CD44v6 expression, which could lead to the inhibition of tumor migration and invasion. Mechanically, we demonstrated that oroxylin A suppressed activation of ERK instead of AKT pathway and then promoted activation of GSK-3β to reduce Snail protein content. Finally, we established transplanted, metastatic, and orthotopic models of A549 cells, and found that oroxylin A inhibited the growth and lung metastasis of A549 cells in vivo. Taken together, we proposed that oroxylin A might be a promising candidate targeting tumor metastasis. © 2016 Wiley Periodicals, Inc.

Topics: A549 Cells; Animals; Antineoplastic Agents; Carcinoma, Non-Small-Cell Lung; Cell Movement; Female; Flavonoids; Glycogen Synthase Kinase 3 beta; Lung; Lung Neoplasms; MAP Kinase Signaling System; Mice, Inbred BALB C; Mice, Nude; Neoplasm Invasiveness; Signal Transduction

Cellular metabolism, particularly glycolysis, is altered during the metastatic process and is highly associated with tumor progression and apoptosis resistance. Oroxylin A, a natural plant flavonoid, exhibits chemopreventive and therapeutic anti-inflammatory and anticancer potential. However, the anticancer effects of oroxylin A on non-small cell lung carcinoma (NSCLC) remain poorly understood.. In vitro studies were performed using 2D and 3D conditions. The effects on anoikis-sensitization and glycolysis-inhibition of oroxylin A in human non-small cell lung cancer A549 cells were examined. In vivo murine lung metastasis experiments were utilized to assess the anti-metastatic capacity of oroxylin A.. ROS-mediated activation of c-Src following detachment caused anoikis resistance in A549 cells. Oroxylin A sensitized A549 cells to anoikis by inactivating the c-Src/AKT/HK II pathway in addition to inducing the dissociation of HK II from mitochondria. Prior to sensitizing A549 cells to anoikis, oroxylin A decreased the ATP level and inhibited glycolysis. Furthermore, oroxylin A inhibited lung metastasis of A549 cells in vivo in nude mice.. Oroxylin A sensitized anoikis, which underlies distinct glucose-deprivation-like mechanisms that involved c-Src and HK II.. The findings in this study indicated that oroxylin A could potentially be utilized in the development of improved metastatic cancer treatments.

Topics: Adenosine Triphosphate; Animals; Anoikis; Antineoplastic Agents; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; CSK Tyrosine-Protein Kinase; Flavonoids; Glucose; Glycolysis; Hexokinase; Humans; Lung Neoplasms; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Mitochondria; src-Family Kinases; Xenograft Model Antitumor Assays