• Biomolecules & Therapeutics
• /
• 제31권3호
• /
• pp.319-329
• /
• 2023

Resistance to hypomethylating agents (HMAs) in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) is a concerning problem. Polo-like kinase 1 (PLK1) is a key cell cycle modulator and is known to be associated with an activation of the PI3K pathway, which is related to the stabilization of DNA methyltransferase 1 (DNMT1), a target of HMAs. We investigated the effects of volasertib on HMA-resistant cell lines (MOLM/AZA-1 and MOLM/DEC-5) derived from MOLM-13, and bone marrow (BM) samples obtained from patients with MDS (BM blasts >5%) or AML evolved from MDS (MDS/AML). Volasertib effectively inhibited the proliferation of HMA-resistant cells with suppression of DNMTs and PI3K/AKT/mTOR and ERK pathways. Volasertib also showed significant inhibitory effects against primary BM cells from patients with MDS or MDS/AML, and the effects of volasertib inversely correlated with DNMT3B expression. The DNMT3B-overexpressed AML cells showed primary resistance to volasertib treatment. Our data suggest that volasertib has a potential role in overcoming HMA resistance in patients with MDS and MDS/AML by suppressing the expression of DNMT3 enzymes and PI3K/AKT/mTOR and ERK pathways. We also found that DNMT3B overexpression might be associated with resistance to volasertib.

• BMB Reports
• /
• 제49권1호
• /
• pp.63-68
• /
• 2016

The serine/threonine kinase mTOR is essential for the phosphoinositide 3-kinases (PI3K) signaling pathway, and regulates the development and function of immune cells. Aberrant activation of mTOR signaling pathway is associated with many cancers including leukemia. Here, we report the contributions of mTOR signaling to growth of human leukemic cell lines and mouse T-cell acute leukemia (T-ALL) cells. Torin, an ATP-competitive mTOR inhibitor, was found to have both cytotoxic and cytostatic effects on U-937, THP-1, and RPMI-8226 cells, but not on Jurkat or K-562 cells. All cells were relatively resistant to rapamycin even with suppressed activity of mTOR complex 1. Growth of T-ALL cells induced by Notch1 was profoundly affected by torin partially due to increased expression of Bcl2l11 and Bbc3. Of note, activation of Akt or knockdown of FoxO1 mitigated the effect of mTOR inhibition on T-ALL cells. Our data provide insight on the effect of mTOR inhibitors on the survival and proliferation of leukemic cells, thus further improving our understanding on cell-context-dependent impacts of mTOR signaling. [BMB Reports 2016; 49(1): 63-68]

• The Korean Journal of Pain
• /
• 제34권2호
• /
• pp.176-184
• /
• 2021

Background: Diabetes-related neuropathic pain frequently occurs, and the underpinning mechanism remains elusive. The periaqueductal gray (PAG) exhibits descending inhibitory effects on central pain transmission. The current work aimed to examine whether inflammatory cytokines regulate mechanical allodynia and thermal hyperalgesia induced by diabetes through the phosphoinositide 3-kinase (PI3K)-mammalian target of rapamycin (mTOR) pathway in the PAG. Methods: Streptozotocin (STZ) was administered intraperitoneally to mimic allodynia and hyperalgesia evoked by diabetes in rats. Behavioral assays were carried out for determining mechanical pain and thermal hypersensitivity. Immunoblot and ELISA were performed to examine PAG protein amounts of interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α), as well as their corresponding receptors in STZ rats, and the expression of PI3K/protein kinase B (Akt)/mTOR signaling effectors. Results: Increased PAG p-PI3K/p-Akt/p-mTOR protein amounts were observed in STZ-induced animals, a PI3K-mTOR pathway inhibition in the PAG attenuated neuropathic pain responses. Moreover, the PAG concentrations of IL-1β, IL-6, and TNF-α and their receptors (namely, IL-1R, IL-6R, and tumor necrosis factor receptor [TNFR] subtype TNFR1, respectively) were increased in the STZ rats. Additionally, inhibiting IL-1R, IL-6R, and TNFR1 ameliorated mechanical allodynia and thermal hyperalgesia in STZ rats, alongside the downregulation of PI3K-mTOR signaling. Conclusions: Overall, the current study suggests that upregulated proinflammatory cytokines and their receptors in the PAG activate PI3K-mTOR signaling, thereby producing a de-inhibition effect on descending pathways in modulating pain transmission, and eventually contributing to neuropathic pain.

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권10호
• /
• pp.5925-5928
• /
• 2013

Objective: This study aimed to examine the relationship between expression of mammal target of rapamycin (mTOR) and phosphorylation of mTOR (p-mTOR) protein in the PI3K/Akt/mTOR signaling pathways in gastrointestinal stromal tumors and relatiuonships with clinical factors. Methods: Immunohistochemistry was used to detect the expression of the associated proteins mTOR, p-mTOR, and phosphorylation of the tumor suppressor genes PTEN, P27, VEGF, and EGFR in 40 cases of gastrointestinal stromal tumors, with division into a very low and low risk group as well as a moderate and high risk group. Results: The positive rate of mTOR and p-mTOR was significantly increased in the moderate and high risk group compared with the very low and low risk group. The difference was statistically significant (P<0.05). When grouped according to size, the positive mTOR expression rate exhibited a statistical difference (P<0.05), which was significantly increased in the group of tumors larger than 5 cm. The difference in the positive mTOR and p-mTOR expression rate exhibit no statistical significance among the PTEN, P27, VEGF, and EGFR expression subgroups (P>0.05). Conclusion: The different expressions of mTOR and p-mTOR in the signal transduction pathway of gastrointestinal stromal tumor in the different degree-of-risk groups suggested that the mTOR and p-mTOR of the signal transduction pathway serve an important function in the occurrence and development of gastrointestinal stromal tumors.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권16호
• /
• pp.6463-6475
• /
• 2014

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.

• 생명과학회지
• /
• 제32권6호
• /
• pp.421-429
• /
• 2022

본 연구에서는 죽상경화 플락에서 발견되는 펩티도글리칸이 혈관염증에서 어떠한 역할을 하는지 알아보기 위하여 염증성 사이토카인의 한 종류인 인터루킨-1 알파의 발현에 대한 영향을 조사하였다. 실험방법으로는 혈관염증을 주도하는 단핵구/대식세포인 THP-1 세포주에 펩티도글리칸을 처리하고 인터루킨-1 알파의 발현을 RT-PCR, real-time PCR, ELISA 방법으로 분석하였다. 펩티도글리칸의 처리 시간과 농도에 비례하여 단핵구/대식세포에서 인터루킨-1 알파의 전사체와 단백질 분비가 증가함을 관찰하였다. 또한 펩티도글리칸의 작용기전을 규명하기 위하여 신호전달을 차단하는 억제제를 세포에 처리하고 인터루킨-1 알파의 발현을 조사하였다. TLR2/4의 억제제인 OxPAPC 그리고 세포 kinase의 작용을 억제하는 LY294002(PI3 kinase 억제), Akti IV (Akt 억제), rapamycin (mTOR 억제), U0126 (MEK 억제), SB202190 (p38 MAPK 억제), SP6001250 (JNK 억제), DPI (NOX 억제)를 처리하는 경우 인터루킨-1 알파 전사체의 발현 그리고 단백질의 분비가 감소되었다. 반면에 LPS의 작용을 억제하는 polymyxin B는 인터루킨-1 알파의 발현에 영향을 주지 않았다. 이상의 결과는, 펩티도글리칸이 TLR2, PI3K, Akt, mTOR, MAPKs를 통하여 단핵구/대식세포의 인터루킨-1 알파 발현을 증가시키고 혈관염증에 기여한다는 것을 나타낸다.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권15호
• /
• pp.6549-6556
• /
• 2015

The PI3K-Akt-mTOR, $Wnt/{\beta}$-catenin and apoptosis signaling pathways have been shown to be involved in genesis of colorectal cancer (CRC). The aim of this study was to elucidate whether combination of Gelam honey and ginger might have chemopreventive properties in HT29 colon cancer cells by modulating the mTOR, $Wnt/{\beta}$-catenin and apoptosis signaling pathways. Treatment with Gelam honey and ginger reduced the viability of the HT29 cells dose dependently with $IC_{50}$ values of 88 mg/ml and 2.15 mg/ml respectively, their while the combined treatment of 2 mg/ml of ginger with 31 mg/ml of Gelam honey inhibited growth of most HT29 cells. Gelam honey, ginger and combination induced apoptosis in a dose dependent manner with the combined treatment exhibiting the highest apoptosis rate. The combined treatment downregulated the gene expressions of Akt, mTOR, Raptor, Rictor, ${\beta}$-catenin, $Gsk3{\beta}$, Tcf4 and cyclin D1 while cytochrome C and caspase 3 genes were shown to be upregulated. In conclusion, the combination of Gelam honey and ginger may serve as a potential therapy in the treatment of colorectal cancer through inhibiton of mTOR, $Wnt/{\beta}$ catenin signaling pathways and induction of apoptosis pathway.

• Asian Pacific Journal of Cancer Prevention
• /
• 제13권6호
• /
• pp.2739-2744
• /
• 2012

Background: Renal-cell carcinoma (RCC) is resistant to almost all chemotherapeutics and radiation therapy. ${\beta}$-Elemene, a promising anticancer drug extracted from a traditional Chinese medicine, has been shown to be effective against various tumors. In the present study, anti-tumor effects on RCC cells and the involved mechanisms were investigated. Methods: Human RCC 786-0 cells were treated with different concentrations of ${\beta}$-elemene, and cell viability and apoptosis were measured by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay and flow cytometry, respectively. Protein expression was assayed by western blotting. Autophagy was evaluated by transmission electron microscopy. Results: ${\beta}$-Elemene inhibited the viability of 786-0 cells in a dose- and time-dependent manner. The anti-tumor effect was associated with induction of apoptosis. Further study showed that ${\beta}$-elemene inhibited the MAPK/ERK as well as PI3K/Akt/mTOR signalling pathways. Moreover, robust autophagy was observed in cells treated with ${\beta}$-elemene. Combined treatment of ${\beta}$-elemene with autophagy inhibitors 3-methyladenine or chlorochine significantly enhanced the anti-tumor effects. Conclusions: Our data provide first evidence that ${\beta}$-elemene can inhibit the proliferation of RCC 786-0 cells by inducing apoptosis as well as protective autophagy. The anti-tumor effect was associated with the inhibition of MAPK/ERK and PI3K/Akt/mTOR signalling pathway. Inhibition of autophagy might be a useful way to enhance the anti-tumor effect of ${\beta}$-elemene on 786-0 cells.

• International Journal of Stem Cells
• /
• 제16권1호
• /
• pp.52-65
• /
• 2023

Background and Objectives: Epithelial-Mesenchymal transition (EMT) is one of the origins of myofibroblasts in renal interstitial fibrosis. Mesenchymal stem cells (MSCs) alleviating EMT has been proved, but the concrete mechanism is unclear. To explore the mechanism, serum-free MSCs conditioned medium (SF-MSCs-CM) was used to treat rat renal tubular epithelial cells (NRK-52E) fibrosis induced by transforming growth factor-β1 (TGF-β1) which ameliorated EMT. Methods and Results: Galectin-3 knockdown (Gal-3 KD) and overexpression (Gal-3 OE) lentiviral vectors were established and transfected into NRK-52E. NRK-52E fibrosis model was induced by TGF-β1 and treated with the SF-MSCs-CM for 24 h after modelling. Fibrosis and autophagy related indexes were detected by western blot and immunocytochemistry. In model group, the expressions of α-smooth muscle actin (α-SMA), fibronectin (FN), Galectin-3, Snail, Kim-1, and the ratios of P-Akt/Akt, P-GSK3β/GSK3β, P-PI3K/PI3K, P-mTOR/mTOR, TIMP1/MMP9, and LC3B-II/I were obviously increased, and E-Cadherin (E-cad) and P62 decreased significantly compared with control group. SF-MSCs-CM showed an opposite trend after treatment compared with model group. Whether in Gal-3 KD or Gal-3 OE NRK-52E cells, SF-MSCs-CM also showed similar trends. However, the effects of anti-fibrosis and enhanced autophagy in Gal-3 KD cells were more obvious than those in Gal-3 OE cells. Conclusions: SF-MSCs-CM probably alleviated the EMT via inhibiting Galectin-3/Akt/GSK3β/Snail pathway. Meanwhile, Gal-3 KD possibly enhanced autophagy via inhibiting Galectin-3/Akt/mTOR pathway, which synergistically ameliorated renal fibrosis. Targeting galectin-3 may be a potential target for the treatment of renal fibrosis.

• 한국식품과학회지
• /
• 제50권1호
• /
• pp.105-110
• /
• 2018

멜리틴은 봉독의 주요 성분 중 하나로 항염증과 항암활성 효과를 가지고 있다. 우리는 폐암세포에서 멜리틴이 EMT 억제를 통해 암세포 이동과 침투를 억제하는 사실을 확인하였다. 멜리틴은 EGF로 유도된 폐암 세포 이동과 침투를 억제하였을 뿐만 아니라 EMT와 관련된 단백질인 이카드헤린의 발현을 증가시켰으며, 바이멘틴과 피브로넥틴 발현은 감소시켰다. 또한 멜리틴에 의한 EMT조절 전사인자인 ZEB2, Slug, Snail의 발현을 확인한 결과 멜리틴 처리에 의해 농도의존적으로 발현이 감소하였다. 또한 작용 메커니즘을 확인하기 위해 mTOR와 FAK 메커니즘을 확인한 실험에서 EGF 처리에 의해 증가한 AKT, mTOR, p70S6K, 4EBP1의 인산화가 멜리틴 농도의존적으로 감소하였다. 그러나 FAK는 EGF에 의해 변화가 없었으며, EKR, JNK 메커니즘은 EGF 처리에 의해 인산화가 증가하였으나 멜리틴 처리에 의해 아무런 영향을 받지 않았다. 그러므로, 폐암세포의 세포 이동과 침투에 대한 멜리틴의 억제효과는 AKT/mTOR/P70S6K/4EBP1 기전 억제를 통해 EMT를 억제하여 세포 이동과 침투를 억제하는 것으로 보인다.