Identification of mTOR inhibitor-resistant genes in cutaneous squamous cell carcinoma

Yu, Seong-Lan,Lee, Dong Chul,Baek, Seung Woo,Cho, Do Yeun,Choi, Jong Gwon,Kang, JaeKu Dove Medical Press 2018 Cancer management and research Vol.10 No.-

<P><B>Purpose</B></P><P>The PI3K/AKT/mTOR pathway is frequently activated in various squamous cell carcinomas (SCCs). Although mTOR inhibitors are suggested as effective treatments in immunosuppressed patients with metastatic SCC, they are still not proven to be favorable in treating skin SCC patients not undergoing immunosuppressive therapy. Moreover, the exact mechanism of the mTOR signaling pathway in SCC has not yet been identified. In this study, we aimed to determine the genes associated with mTOR inhibitors in skin SCC.</P><P><B>Materials and methods</B></P><P>The identification of cell viability according to concentration of everolimus and Western blot was done. To analyze the global gene expression profiles, A431 and HSC-1 cells were treated with dimethyl sulfoxide (DMSO) or 100 nM of everolimus for 72 hours. Furthermore, differentially expressed genes (DEGs) were identified using Affymetrix analysis. To identify the gene network associated with everolimus resistance in SCC cells, pathway analysis was performed using the Ingenuity Pathway Analysis (IPA) tool.</P><P><B>Results</B></P><P>The effects of cell death with respect to the mTOR inhibitor concentration were observed in the HSC-1 cell line; however, the mTOR inhibitor did not show effective cytotoxic activity in the A431 cell line. p-mTOR concentration also diminished with respect to everolimus concentrations in the HSC-1 cell line. Moreover, the microarray results showed that the <I>MYC/CCND1/TP73/NUPR1/SBD/ERBB2/CDKN2B</I> genes were related to mTOR inhibitor resistance. However, CCND1 gene overexpression was most closely related to mTOR inhibitor resistance.</P><P><B>Conclusion</B></P><P>We identified mTOR inhibitor resistance genes, and our findings may help select therapeutic targets in skin SCC.</P>

노화관련 질환에서 mTOR의 억제제의 임상적 적용과 가능성

신현영(Hyun-Young Shin),추상희(Sang Hui Chu),이향규(Hyangkyu Lee),이지원(Ji Won Lee) 대한임상노인의학회 2011 대한임상노인의학회지 Vol.12 No.4

mTOR (mammalian target of rapamycin)는 PI3K-related family kinase에 속하는 serine/threonine kinase로 성장인자(growth factor)와 영양, 스트레스 자극에 의하여 세포의 성장과 증식, 자가포식(autophagy), 단백질 합성을 조절하는 기능이 있는 것으로 알려져 왔다 mTOR 억제제는 현재 면역억제의 역할 때문에 신이식을 받은 환자들에게 널리 사용되고 있으며 일부 암에서 항암작용이 증명되어 항암제로 사용되고 있으며 다양한 암질환에서 임상시험이 진행되고 있다. 최근 mTOR 기전은 비만, 당뇨병을 포함한 대사질환, 신경퇴행성 질환, 심혈관 질환 등의 노화관련 질환과 관련이 있다고 알려졌을 뿐 아니라, mTOR 억제제의 직접적인 수명연장 가능성이 제시되어 많은 연구들이 진행 중에 있다. 하지만 노화와 관련된 mTOR 메커니즘 연구는 아직 기초 단계에 머물러 있으며, 면역억제를 할 경우 생길 수 있는 감염의 증가 등 mTOR 억제제 관련 부작용을 규명하는 연구들이 필요하다. 향후 mTOR 억제제 관련 연구는 건강한 수명연장을 위해 기반 연구에 도움을 줄 것으로 기대한다. mTOR (mammalian target of rapamycin) is a serine/threonine kinase belonging to the PI3K (phosphoinositide 3-kinase)-related family kinase. mTOR is known to regulate cell growth, proliferation, autophagy and protein synthesis in response to growth factor, nutrient, stress. mTOR inhibitor has been broadly used as an immunosuppressant for kidney transplant patients. Clinical results of the data have showed mTOR inhibitor as an anticancer agent to several kinds of cancers and many clinical trials are still undergoing. Recently, mTOR signaling pathway has been studied with, not only metabolic disease, neurodegenerative disease, cardiovascular disease, which are related to the ageing process, but also the possibility of direct prolongation of human life. However, the studies of mTOR pathway with age-related disease are still in the early stage, we need more studies about increasing infectivity after immunosuppression and other adverse events of mTOR inhibitor. In this article, we will review age-related disease with mTOR pathway and discuss mTOR inhibitor as a potential agent for extending healthy life in the future.

항암제 개발: 토포아이소머라제, HSP90, mTOR 및 티로신키나제 억제제

최경철(Kyoungcheol Choi),이성호(Seongho Lee),권미지(Miji Kwon),홍세영(Seyoung Hong),박희호(Hee Ho Park),임광석(Kwang Suk Lim) 한국생물공학회 2021 KSBB Journal Vol.36 No.2

Chemical anticancer drugs that have been used for a long time for the treatment of cancer have high anticancer effects and many side effects. The side effects of anticancer drugs have also affected normal cells because they induce the death of cancer cells by inhibiting or blocking essential mechanisms for cell survival. Recently, inhibitory drugs that inhibit specific mechanisms of cancer cells are receiving a lot of attention as anticancer drugs. Inhibitory drugs have less effect on normal cells by inhibiting the activity of target proteins that are overexpressed in cancer cells. Representative anticancer inhibitors among many inhibitory drugs are mTOR inhibitors, topoisomerase inhibitors, heat shock protein 90 (HSP90) inhibitors and tyrosine kinase inhibitors. For each of these inhibitor family, new candidate inhibitor drugs are continuously being developed and clinical trials are underway. In this review, we will examine the drug mechanism of each inhibitor drug, and describe the approved drugs and drugs in clinical trials.

Activation of WNT/β‐catenin signaling results in resistance to a dual PI3K/mTOR inhibitor in colorectal cancer cells harboring <i>PIK3CA</i> mutations

Park, Ye‐,Lim,Kim, Hwang‐,Phill,Cho, Young‐,Won,Min, Dong‐,Wook,Cheon, Seul‐,Ki,Lim, Yoo Joo,Song, Sang‐,Hyun,Kim, Sung Jin,Han, Sae‐,Won,Park, Kyu Joo,Kim, T John Wiley Sons, Inc. 2019 International journal of cancer: Journal internati Vol.144 No.2

<P><I>PIK3CA</I> is a frequently mutated gene in cancer, including about ~15 to 20% of colorectal cancers (CRC). <I>PIK3CA</I> mutations lead to activation of the PI3K/AKT/mTOR signaling pathway, which plays pivotal roles in tumorigenesis. Here, we investigated the mechanism of resistance of <I>PIK3CA</I>‐mutant CRC cell lines to gedatolisib, a dual PI3K/mTOR inhibitor. Out of a panel of 29 CRC cell lines, we identified 7 harboring one or more <I>PIK3CA</I> mutations; of these, 5 and 2 were found to be sensitive and resistant to gedatolisib, respectively. Both of the gedatolisib‐resistant cell lines expressed high levels of active glycogen synthase kinase 3‐beta (GSK3β) and harbored the same frameshift mutation (c.465_466insC; H155fs*) in <I>TCF7</I>, which encodes a positive transcriptional regulator of the WNT/β‐catenin signaling pathway. Inhibition of GSK3β activity in gedatolisib‐resistant cells by siRNA‐mediated knockdown or treatment with a GSK3β‐specific inhibitor effectively reduced the activity of molecules downstream of mTOR and also decreased signaling through the WNT/β‐catenin pathway. Notably, GSK3β inhibition rendered the resistant cell lines sensitive to gedatolisib cytotoxicity, both <I>in vitro</I> and in a mouse xenograft model. Taken together, these data demonstrate that aberrant regulation of WNT/β‐catenin signaling and active GSK3β induced by the <I>TCF7</I> frameshift mutation cause resistance to the dual PI3K/mTOR inhibitor gedatolisib. Cotreatment with GSK3β inhibitors may be a strategy to overcome the resistance of <I>PIK3CA</I>‐ and <I>TCF7</I>‐mutant CRC to PI3K/mTOR‐targeted therapies.</P>

소라페닙 이후의 간세포암 표적 치료제

김강모 대한간학회 2014 간학회 싱글토픽 심포지움 Vol.2014 No.2

Sorafenib is the only approved systemic molecular targeted agent (MTA) for advanced stage hepatocellular carcinoma (HCC). However, because of the modest efficacy of sorafenib on HCC, there has been huge need for more efficacious MTAs in the treatment of HCC. Increasing knowledge of molecular hepatocarcinogenesis becomes the basis for the search of novel therapeutic targets in HCC and this includes genetic and epigenetic alteration, growth/angiogenic factors and signaling pathways, immunologic changes, and arginine metabolism in HCC. A lot of new MTAs have been and are being studied in clinical trials, and these MTAs are categorized to multikinase inhibitors, MET inhibitors, antiangiogenic agents and mTOR inhibitors. Several combination regimens of two MTAs and immunologic modulator is an another new attempt in HCC clinical trials. This review will summarize the result and the current status of various novel MTAs in the treatment of HCC.

Identification of a Novel Oxadiazole Inhibitor of Mammalian Target of Rapamycin

Sunwoo Lim,Hyomin Lee,김의정,허우영 대한화학회 2020 Bulletin of the Korean Chemical Society Vol.41 No.3

We performed a biochemical screen against mTOR using in-house small molecule library. Two novel, structurally distinct hits were identified. Among them, a novel oxadiazole scaffold compound (2) suppressed the phosphorylation of both S6K1 and Akt1 in HeLa cells. Docking study suggested that 2 is ATP-competitive and shows a pi-pi interaction with Trp2239 and hydrogen bonds with Trp2239 and Thr2245. Through derivatization, a slightly more potent analogue (2a) was identified with IC50 of 9.6 ?M. Our study provides a starting point for discovery of novel potent mTOR inhibitors.

Combination Therapy with a PI3K/mTOR Dual Inhibitor and Chloroquine Enhances Synergistic Apoptotic Cell Death in Epstein-Barr Virus-Infected Gastric Cancer Cells

Kim, Mi-Young,Kruger, Annie J.,Jeong, Ju-Yeon,Kim, Jaehee,Shin, Phil kyung,Kim, Sun Young,Cho, Joo Young,Hahm, Ki Baik,Hong, Sung Pyo Korean Society for Molecular and Cellular Biology 2019 Molecules and cells Vol.42 No.6

The phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling pathway is a promising target for gastric cancer (GC) treatment; however the efficacy of PI3K/mTOR dual inhibitors in GC has not yet been maximized. Additionally, the effect of autophagy regulation by PI3K/mTOR dual inhibitors has not been clearly elucidated in GC treatment. We aimed to show that our newly developed PI3K/mTOR dual inhibitor, CMG002, when combined with an autophagy inhibitor, chloroquine (CQ), potently induces effective cancer cell death in Epstein-Barr virus (EBV)-associated gastric cancer (EBVaGC) cells, where both the PI3K/AKT/mTOR and autophagy pathways play important roles in disease pathogenesis. EBV- and mock-infected AGS and NUGC3 GC cell lines were treated with CMG002 +/- CQ. PI3K/AKT/mTOR signaling pathway mediators, cellular apoptosis and autophagy markers were confirmed by Western blot assay. Cell viability was assessed using the Cell Counting Kit-8 (CCK-8) assay. CMG002 effectively blocked the PI3K/AKT/mTOR pathway by markedly decreasing phosphorylation of AKT and its downstream mediator S6. CMG002 induced G0/G1 cell cycle arrest and enhanced apoptotic cell death in AGS and NUGC3 cells, particularly EBV-infected cells compared with mock-infected cells, as confirmed by flow cytometric analyses and TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) assays. The combination of CMG002 plus CQ synergistically increased apoptotic cell death in EBV-infected GC cell lines when compared with CMG002 alone (P < 0.05). Our results suggest that the new PI3K/mTOR dual inhibitor, CMG002, when used in combination with the autophagy inhibitor, CQ, provides enhanced therapeutic efficacy against EBVaGC.

Combination Therapy with a PI3K/mTOR Dual Inhibitor and Chloroquine Enhances Synergistic Apoptotic Cell Death in Epstein–Barr Virus-Infected Gastric Cancer Cells

김미영,Annie J. Kruger,정주연,김재희,신필경,김선영,조주영,함기백,홍성표 한국분자세포생물학회 2019 Molecules and cells Vol.42 No.6

The phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling pathway is a promising target for gastric cancer (GC) treatment; however the efficacy of PI3K/mTOR dual inhibitors in GC has not yet been maximized. Additionally, the effect of autophagy regulation by PI3K/mTOR dual inhibitors has not been clearly elucidated in GC treatment. We aimed to show that our newly developed PI3K/mTOR dual inhibitor, CMG002, when combined with an autophagy inhibitor, chloroquine (CQ), potently induces effective cancer cell death in Epstein–Barr virus (EBV)-associated gastric cancer (EBVaGC) cells, where both the PI3K/AKT/mTOR and autophagy pathways play important roles in disease pathogenesis. EBV- and mock-infected AGS and NUGC3 GC cell lines were treated with CMG002 +/– CQ. PI3K/AKT/mTOR signaling pathway mediators, cellular apoptosis and autophagy markers were confirmed by Western blot assay. Cell viability was assessed using the Cell Counting Kit-8 (CCK-8) assay. CMG002 effectively blocked the PI3K/AKT/mTOR pathway by markedly decreasing phosphorylation of AKT and its downstream mediator S6. CMG002 induced G0/G1 cell cycle arrest and enhanced apoptotic cell death in AGS and NUGC3 cells, particularly EBV-infected cells compared with mock-infected cells, as confirmed by flow cytometric analyses and TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) assays. The combination of CMG002 plus CQ synergistically increased apoptotic cell death in EBV-infected GC cell lines when compared with CMG002 alone (P < 0.05). Our results suggest that the new PI3K/mTOR dual inhibitor, CMG002, when used in combination with the autophagy inhibitor, CQ, provides enhanced therapeutic efficacy against EBVaGC.

A novel PI3K/mTOR dual inhibitor, CMG002, overcomes the chemoresistance in ovarian cancer

Choi, Hye Joung,Heo, Jin Hyung,Park, Ju Yeon,Jeong, Ju Yeon,Cho, Hyeon Ju,Park, Kyung Soon,Kim, Se Hwa,Moon, Yong Wha,Kim, Jin Sung,An, Hee Jung Elsevier 2019 Gynecologic oncology Vol.153 No.1

<P><B>Abstract</B></P> <P><B>Objective</B></P> <P>Ovarian cancer is the leading cause of gynecologic-related mortality worldwide. Despite successful initial treatment, overall survival rates are very low because tumors develop resistance to chemotherapeutic drugs. The PI3K/mTOR pathway is a key signaling pathway involved in drug resistance of ovarian cancer cells. The aim of this study was to examine the effect of a newly developed PI3K/mTOR dual inhibitor, CMG002, on chemoresistant ovarian cancer cells.</P> <P><B>Methods</B></P> <P>We examined the effects of CMG002, and its synergistic effects when combined with paclitaxel or cisplatin, on cell viability, cell cycle arrest, and apoptosis of PTX-resistant SKpac17 or cisplatin-resistant A2780cis ovarian cancer cells <I>in vitro</I>. Western blot analysis was performed to assess expression of PI3K, p-mTOR, p-Akt, p-S6, Bim, and caspase-3. <I>In vivo</I> studies were carried out in a xenograft mouse model, followed by TUNEL and immunohistochemical staining of excised tumor tissue.</P> <P><B>Results</B></P> <P>CMG002 showed marked toxicity against chemoresistant ovarian cancer cells and re-sensitized these cells to chemotherapeutic agents by suppressing cell proliferation and inducing G1 cell cycle arrest and apoptosis. <I>In vivo</I> xenograft studies revealed that treatment with CMG002, either alone or in combination with paclitaxel or cisplatin, led to a marked reduction in tumor growth. CMG002 caused marked suppression of mTOR (Ser2448), Akt (Ser473), Akt (Thr308), and S6 (Ser235/236) phosphorylation, both <I>in vitro</I> and <I>in vivo</I>.</P> <P><B>Conclusion</B></P> <P>Taken together, CMG002, a very potent PI3K/mTOR dual inhibitor, induced cytotoxicity in chemoresistant ovarian cancer cells, suggesting that this novel inhibitor might be a new therapeutic strategy for chemoresistant ovarian cancer.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel PI3K/mTOR dual inhibitor, CMG002, is newly developed. </LI> <LI> We demonstrate here for the first time that CMG002 inhibits growth of chemoresistant cancer cells both <I>in vitro</I> and <I>in vivo</I>. </LI> <LI> CMG002 suppresses cell proliferation and induces G1 cell cycle arrest and apoptosis in chemoresistant ovarian cancer cells. </LI> <LI> CMG002 re-sensitizes chemoresistant cancer cells to PTX or platinum agents. </LI> <LI> CMG002 is a promising therapeutic strategy for chemoresistant ovarian cancer. </LI> </UL> </P>

The mTOR Signalling Pathway in Cancer and the Potential mTOR Inhibitory Activities of Natural Phytochemicals

Tan, Heng Kean,Moad, Ahmed Ismail Hassan,Tan, Mei Lan Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.16

The mammalian target of rapamycin (mTOR) kinase plays an important role in regulating cell growth and cell cycle progression in response to cellular signals. It is a key regulator of cell proliferation and many upstream activators and downstream effectors of mTOR are known to be deregulated in various types of cancers. Since the mTOR signalling pathway is commonly activated in human cancers, many researchers are actively developing inhibitors that target key components in the pathway and some of these drugs are already on the market. Numerous preclinical investigations have also suggested that some herbs and natural phytochemicals, such as curcumin, resveratrol, timosaponin III, gallic acid, diosgenin, pomegranate, epigallocatechin gallate (EGCC), genistein and 3,3'-diindolylmethane inhibit the mTOR pathway either directly or indirectly. Some of these natural compounds are also in the clinical trial stage. In this review, the potential anti-cancer and chemopreventive activities and the current status of clinical trials of these phytochemicals are discussed.