TRAIL (IC50 = 64.6±9.1 µM)

LY303511 does not potently inhibit PI3K despite sharing a structural similarity with LY294002 other than the substitution of -O for -NH in the morpholine ring. When cells are treated with LY303511, calcein spread rises to levels similar to those of LY294002. AKT phosphorylation is inhibited by LY303511, but this effect does not coincide with increased gap junctional intercellular communication (GJIC), as determined by immunoblotting[1]. By activating H2O2-MAPK and upregulating death receptors, the drug LY303511 makes SHEP-1 neuroblastoma cells more susceptible to the effects of TRAIL. SHEP-1 cells are exposed to LY303511 (LY30), TRAIL, and a combination of the two (1 hour of LY303511 preincubation followed by 4 hours of TRAIL exposure) at various concentrations. Although LY303511 (12.5, 25, or 50 μM) treatment has no impact on cell viability, SHEP-1 cells are responsive to TRAIL (10%, 15%, and 30% reduction in the surviving fraction at 25, 50, and 100 ng/mL, respectively). The combination of LY303511 (25 M) and TRAIL (50 ng/mL) for 4 hours, followed by the incubation of the cells, has a strong synergistic effect (40% reduction in viable cells with LY303511+TRAIL versus 15% with TRAIL alone)[2]. Regarding PI3K activity, LY303511 serves as a negative control substance. Wortmannin (100 nM) in MIN6 insulinoma cells has no effect on whole-cell outward K+ currents, but LY294002 and LY303511 reversibly block currents in a dose-dependent manner (IC50=9.0±0.7 μM and 64.6±9.1 μM, respectively). Beta cells have high levels of Kv2.1 and Kv1.4 expression. In Kv2.1-transfected tsA201 cells, LY294002 and LY303511 reversibly inhibit currents by ~90 and 41%, respectively. LY303511 inhibits currents with an IC50 of 64.6±9.1 µM and a maximum inhibitory concentration of 500 μM (n≥5 cells at each concentration)[3].

Intraperitoneal administration of vehicle or LY303511 (10 mg/kg/day) is performed when tumors reach a volume of ~150 mm3, at which time 35 mice have developed a tumor. Since the average tumor volume was estimated to be unreliable, the data were censored after 21 days because >15% of the mice needed to be put to sleep due to excessive tumor growth. The PC-3 tumor can be prevented from growing in vivo by administering LY303511 at a dose of 10 mg/kg/day[4].

LY303511 is structurally identical to LY294002 except for a substitution of -O for -NH in the morpholine ring, and does not potently inhibit PI3K. Treatment of cells with LY303511 causes an increase in calcein spread similar to levels of LY294002. The ability of LY303511 to increase gap junctional intercellular communication (GJIC) does not occur concomitant with inhibition of phosphorylation of AKT as measured by immunoblotting.

Human neuroblastoma SHEP-1 cells are maintained in DMEM supplemented with 10% fetal bovine serum and 1% Penicillin. In a typical survival assay, LY303511 (12.5, 25, and 50 μM), TRAIL (25, 50, and 100 ng/mL), and a combination of the two (1 h preincubation with LY303511 followed by TRAIL for 4 h) are exposed to SHEP-1 cells (8×104 per well) plated in 24-well plates for 24 h. The crystal violet assay is used to determine cytotoxicity. Following drug exposure, cells are PBS washed and then incubated with 200 μL of crystal violet solution for 20 min. The remaining crystals are dissolved in 20% acetic acid after the excess crystal violet solution has been removed with distilled water. Using an automated ELISA reader, absorbance at 595 nm wavelength is used to assess viability. Cell viability experiments are performed similarly with 2,000 units/mL of catalase, 4 μM JNK inhibitor SP600125, 10 μM p38 inhibitor SB202190, 20 μM MAPK/ERK kinase (MEK) inhibitor PD98059, 50 μM of caspase-8 inhibitor Z-IETD-FMK or pan-caspase inhibitor Z-VAD-FMK, or death receptor blocking antibodies (4 μg/mL anti-DR4 or 1 μg/mL anti-DR5), or in cells transfected with small interfering RNA (siRNA) for silencing JNK and ERK expression, respectively. Before adding TRAIL, cells are pre-incubated for 1 hour with LY303511 and the appropriate inhibitor or catalase.

In zebrafish model, LY303511 inhibits CAL 27-xenografted tumor growth. Therefore, LY303511 displays antiproliferation potential against oral cancer cells in vitro and in vivo. https://pubmed.ncbi.nlm.nih.gov/31115172/

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Human prostate adenocarcinoma (PC-3) cells (ATCC CRL-1435) are cultured and implanted (1×10~6 cells) in 20% Matrigel per athymic NCR nude mouse by subcutaneous injection at the flank. Inoculated mice are subdivided into four groups of 10. Administration of vehicle or LY303511, 10 mg/kg/day, is begun (day 1) when tumors reach ~150 mm3 (n=35), and tumor volumes are measured for 30 days at the indicated time points.[4]

[1]. Homotypic gap junctional communication associated with metastasis suppression increases with PKA activity and is unaffected by PI3K inhibition. Cancer Res. 2010 Dec 1;70(23):10002-11.

[2]. The phosphatidylinositol 3-kinase inhibitor LY294002 potently blocks K(V) currents via a direct mechanism. FASEB J. 2003 Apr;17(6):720-2.

[3]. LY303511 enhances TRAIL sensitivity of SHEP-1 neuroblastoma cells via hydrogen peroxide-mediated mitogen-activated protein kinase activation and up-regulation of death receptors. Cancer Res. 2009 Mar 1;69(5):1941-50.

[4]. LY303511 (2-piperazinyl-8-phenyl-4H-1-benzopyran-4-one) acts via phosphatidylinositol 3-kinase-independent pathways to inhibit cell proliferation via mammalian target of rapamycin (mTOR)- and non-mTOR-dependent mechanisms. J Pharmacol E. 2005 Sep;314(3):1134-43.

Loss of gap junctional intercellular communication (GJIC) between cancer cells is a common characteristic of malignant transformation. This communication is mediated by connexin proteins that make up the functional units of gap junctions. Connexins are highly regulated at the protein level and phosphorylation events play a key role in their trafficking and degradation. The metastasis suppressor breast cancer metastasis suppressor 1 (BRMS1) upregulates GJIC and decreases phosphoinositide-3-kinase (PI3K) signaling. On the basis of these observations, we set out to determine whether there was a link between PI3K and GJIC in tumorigenic and metastatic cell lines. Treatment of cells with the well-known PI3K inhibitor LY294002, and its structural analogue LY303511, which does not inhibit PI3K, increased homotypic GJIC; however, we found the effect to be independent of PI3K/AKT inhibition. We show in multiple cancer cell lines of varying metastatic capability that GJIC can be restored without enforced expression of a connexin gene. In addition, while levels of connexin 43 remained unchanged, its relocalization from the cytosol to the plasma membrane was observed. Both LY294002 and LY303511 increased the activity of protein kinase A (PKA). Moreover, PKA blockade by the small molecule inhibitor H89 decreased the LY294002/LY303511-mediated increase in GJIC. Collectively, our findings show a connection between PKA activity and GJIC mediated by PI3K-independent mechanisms of LY294002 and LY303511. Manipulation of these signaling pathways could prove useful for antimetastatic therapy.[1]

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We recently reported that LY294002 (LY29) and LY303511 (LY30) sensitized tumor cells to drug-induced apoptosis independent of the phosphoinositide 3-kinase/Akt pathway. Here, we investigated the mechanism of LY30-induced sensitization of human neuroblastoma cells to TRAIL-mediated apoptosis. We provide evidence that LY30-induced increase in intracellular H(2)O(2) up-regulates the expression of TRAIL receptors (DR4 and DR5) in SHEP-1 cells by activating mitogen-activated protein kinases, resulting in a significant amplification of TRAIL-mediated caspase-8 processing and activity, cytosolic translocation of cytochrome c, and cell death. Involvement of the death receptors was further confirmed by the ability of blocking antibodies against DR4 and/or DR5 to inhibit LY30-induced TRAIL sensitization. Pharmacologic inhibition of c-Jun NH(2) terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) activation by SP600125 and PD98059, respectively, blocked LY30-induced increase in sensitization to TRAIL-mediated death. Finally, small interfering RNA-mediated gene silencing of JNK and ERK inhibited LY30-induced increase in surface expression of DR4 and DR5, respectively. These data show that JNK and ERK are two crucial players involved in H(2)O(2)-mediated increase in TRAIL sensitization of tumor cells upon exposure to LY30 and underscore a novel mode of action of this inactive analogue of LY29. Our findings could have implications for the use of LY30 and similar compounds for enhancing the apoptotic sensitivity of neuroblastoma cells that often become refractory to chemotherapy.[3]

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Mammalian target of rapamycin (mTOR), a serine/threonine kinase, regulates cell growth and proliferation in part via the activation of p70 S6 kinase (S6K). Rapamycin is an antineo-plastic agent that, in complex with FKBP12, is a specific inhibitor of mTOR through interaction with its FKBP12-rapamycin binding domain, thereby causing G(1) cell cycle arrest. However, cancer cells often develop resistance to rapamycin, and alternative inhibitors of mTOR are desired. 2-(4-Morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002) blocks mTOR kinase activity, but it also inhibits phosphatidylinositol 3-kinase (PI3K), an enzyme that regulates cellular functions other than proliferation. We hypothesized that a close structural analog, 2-piperazinyl-8-phenyl-4H-1-benzopyran-4-one (LY303511) might inhibit mTOR-dependent cell proliferation without unwanted effects on PI3K. In human lung epithelial adenocarcinoma (A549) cells, LY303511, like rapamycin, inhibited mTOR-dependent phosphorylation of S6K, but not PI3K-dependent phosphorylation of Akt. LY303511 blocked proliferation in A549 as well as in primary pulmonary artery smooth muscle cells, without causing apoptosis. In contrast to rapamycin, LY303511 reduced G(2)/M progression as well as G(2)/M-specific cyclins in A549 cells. Consistent with an additional mTOR-independent kinase target, LY303511 inhibited casein kinase 2 activity, a known regulator of G(1) and G(2)/M progression. In addition to its antiproliferative effect in vitro, LY303511 inhibited the growth of human prostate adenocarcinoma tumor implants in athymic mice. Given its inhibition of cell proliferation via mTOR-dependent and independent mechanisms, LY303511 has therapeutic potential with antineoplastic actions that are independent of PI3K inhibition.[4]

C₁₉H₁₉CLN₂O₂

342.82

342.113

C, 74.49; H, 5.92; N, 9.14; O, 10.44

2070014-90-1

LY 303511;154447-38-8; 854127-90-5 (2HCl); 2070014-90-1 (HCl)

78357796

White to light yellow solid

2

4

2

24

464

0

Cl.O1C2C(=CC=CC=2C(C=C1N1CCNCC1)=O)C1C=CC=CC=1

QGVSIVYHHKLHPY-UHFFFAOYSA-N

InChI=1S/C19H18N2O2.ClH/c22-17-13-18(21-11-9-20-10-12-21)23-19-15(7-4-8-16(17)19)14-5-2-1-3-6-14;/h1-8,13,20H,9-12H2;1H

8-phenyl-2-piperazin-1-ylchromen-4-one;hydrochloride

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: ≥ 2.5 mg/mL (7.29 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (7.29 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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 (Please use freshly prepared in vivo formulations for optimal results.)