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Chronic exposure to TGFβ, a frequent occurrence for tumor cells in the tumor microenvironment, confers more aggressive phenotypes on cancer cells by promoting their invasion and migration while at the same time increasing their resistance to the growth-inhibitory effect of TGFβ. In this study, a transdifferentiated (TD) A549 cell model, established by chronically exposing A549 cells to TGFβ, showed highly invasive phenotypes in conjunction with attenuation of Smad-dependent signaling. We show that Snail protein, the mRNA expression of which strongly correlates with a poor prognosis in lung cancer patients, was highly stable in TD cells after TGFβ stimulation. The increased protein stability of Snail in TD cells correlated with elevated inhibitory phosphorylation of GSK3β, resulting from the high Akt activity. Notably, integrin β3, whose expression was markedly increased upon sustained exposure to TGFβ, was responsible for the high Akt activity as well as the increased Snail protein stability in TD cells. Consistently, clinical database analysis on lung cancer patients revealed a negative correlation between overall survival and integrin β3 mRNA levels. Therefore, we suggest that the integrin β3-Akt-GSK3β signaling axis plays an important role in non-canonical TGFβ signaling, determining the invasive properties of tumor cells chronically exposed to TGFβ.

Small molecules to selectively induce cell death of undifferentiated human pluripotent stem cells (hPSCs) have been developed with the aim of lowering the risk of teratoma formation during hPSC-based cell therapy. In this context, we have reported that Quercetin (QC) induces cell death selectively in hESCs via p53 mitochondrial localization. However, the detailed molecular mechanism by which hESCs undergo selective cell death induced by QC remains unclear.Herein, we demonstrate that mitochondrial reactive oxygen species (ROS), strongly induced by QC in human embryonic stem cells (hESCs) but not in human dermal fibroblasts (hDFs), were responsible for QC-mediated hESC’s cell death. Increased p53 protein stability and subsequent mitochondrial localization by QC treatment triggered mitochondrial cell death only in hESCs. Of interest, peptidylprolyl isomerase D [PPID, also called cyclophilin D (CypD)], which functions in mitochondrial permeability transition and mitochondrial cell death, was highly expressed in hESCs. Inhibition of CypD by cyclosporine A (CsA) clearly inhibited the QC-mediated loss of mitochondrial membrane potential and mitochondrial cell death. These results suggest that p53 and CypD in the mitochondria are critical for the QC-mediated induction of cell death in hESCs.

Metastasis and chemoresistance, which are main causes of lung cancer related death, have been major interest in cancer research. Recently, Epithelial-Mesenchymal Transition (EMT) a foremost process for acquiring metastatic properties has been demonstrated to be strongly link to chemoresistance. Due to limited understanding of mechanism for EMT mediated chemoresistance, druggable targets for chemoresistance remained unidentified yet. In this study, we established the mesenchymal like cancer cells (MLCCs) from A549 lung cancer cells with chronic exposure of TGFβ. With clinicogenomics database analysis and following validation with MLCC model, we determined that BCL2, of which expression was clearly induced and indicated a poor prognosis in the mesenchymal cancer patients, was responsible for high chemoresistance in MLCCs. Therefore combined treatment of chemotherapeutic drug and BH3 mimetic such as ABT-263 or ABT-737, remarkably sensitized MLCCs to chemo and radio therapy. Furthermore, BCL2 expression was governed by sustained ERK1 activity in MLCCs, which resulted from high level of MEK partner-1 (MP1) protein expression. Therefore, combined chemotherapy with small molecules (approved by FDA or clinically tested) targeting for MEK1 or BCL2 would be a clinically feasible approach to overcome EMT related chemoresistance. Citation Format: Ok-Seon Kwon, Soon-Ki Hong, Hyuk-Jin Cha. BCL2 induced by LAMTOR3-MAPK is a druggable target of chemoradioresistance in mesenchymal lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4761. doi:10.1158/1538-7445.AM2017-4761

The Fluorescent Ubiquitination-based Cell Cycle Indicator (FUCCI) system can be used not only to study gene expression at a specific cell cycle stage, but also to monitor cell cycle transitions in real time. In this study, we used a single clone of FUCCI-expressing HeLa cells (FUCCI-HeLa cells) and monitored the cell cycle in individual live cells over time by determining the ratios between red fluorescence (RF) of RFP-Cdt1 and green fluorescence (GF) of GFP-Geminin. Cytotoxic and cytostatic compounds, the latter of which induced G2 or mitotic arrest, were identified based on periodic cycling of the RF/GF and GF/RF ratios in FUCCI-HeLa cells treated with anti-cancer drugs. With this cell cycle monitoring system, ten flavonoids were screened. Of these, apigenin and luteolin, which have a flavone backbone, were cytotoxic, whereas kaempferol, which has a flavonol backbone, was cytostatic and induced G2 arrest. In summary, we developed a system to quantitatively monitor the cell cycle in real time. This system can be used to identify novel compounds that modulate the cell cycle and to investigate structure–activity relationships.

Background: c-MET is co-expressed with EGFR in approximately 70% of EGFR mutant-positive tumors. In addition, c-Met amplification was found in 10-20% of lung cancer patients with acquired tolerance to EGFR TKI, and c-Met overexpression was found in 14-69% of patients receiving EGFR TKI. CKD-702, a double antibody, is designed to simultaneously block both EGFR and c-MET expression. Purpose: We evaluated the anti-tumor efficacy of CKD-702 with PDX model derived from lung adenocarcinoma patients. Methods: We constructed the PDX model by transplanting surgical tissue from lung adenocarcinoma patient into NOD/SCID mice after the approval of research protocol in Seoul St. Mary's Hospital IRB. We confirmed the co-existence of activating EGFR mutation and c-MET amplification with PNAclamp and FISH methods. We also checked overexpression of EGFR and c-MET protein by immunohistochemistry. Results: The characteristics of tumor tissue transplanted for PDX model were: 1) Korean, lung cancer with EGFR TKI chemotherapy failure confirmed c-MET amplification (> 5 copies) and overexpression (IHC score 3+), 19del Positive EGFR mutation, 2) European lung adenocarcinoma, c-MET amplification (> 2.5 copy) and overexpression (IHC score 3+) were confirmed, and L858R EGFR mutation positive tumor tumor confirmed. The anti-cancer efficacy of CKD-702 was reduced by more than 80% compared to the tumor size of the control group regardless of the concentration. In the CKD-702 20mg/kg group, there was no significant difference in the change in the overall tumor size until the time of disappearing or ending during drug administration. The %TGI was 93.6 and 97.5 according to the concentration of CKD-702, and the % TGD was 118.5 and 311.8, respectively. CKD-702 has a significantly higher tumor growth inhibitory effect regardless of the concentration, but the tumor growth retardation effect is 2.6 times different depending on the concentration. % TGI of CKD-702 20mg / kg group was similar to Hu8c4 group or Hu8c4 + Vectibix group. However, % TGD was 1.4 times higher than Hu8c4 group efficacy and 3.1 times higher than Hu8c4 + Vectibix group% TGD. Even after the completion of drug administration, tumor still remained at 47 days and 67 days in the CKD-702 10 mg/kg and 20 mg/kg groups, respectively. Although c-MET protein expression decreased during the administration of CKD-702, it was confirmed that c-MET protein expression increased again in tumor tissue at the time of tumor growth. Although the tumor size was rather large (605.6 ~ 816.2mm3), CKD-702 showed twice the tumor growth inhibition effect (% TGI: 32.8 vs. 68.1) and the tumor growth delay effect was 4.4 times higher depending on the drug concentration (% TGI: 2.8 vs 12.3). Conclusion: Our data showed that CKD-702 have effective anti-tumor activity in EGFR TKI-resistant PDX model harboring both activating EGFR mutation and c-MET overexpression. Citation Format: Jung-Young Shin, Min-Young Kim, Mi-Ran Lee, Jeong-Oh Kim, Eun-Ju Jeon, Ji Hye Choi, Soon-Ki Hong, Kyu-Jin Park, Jin Hyoung Kang. Anti-tumor efficacy of CKD-702 in EGFR TKI-resistant patient-derived xenograft model [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3046.

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