Beilei Wang

Upconverting Near‐Infrared Light through Energy Management in Core–Shell–Shell Nanoparticles

Lanthanide-doped upconversion materials, capable of converting low-density (< 1000 W cm ) near-infrared (NIR) excitation to ultraviolet (UV) and visible emissions, have generated a large amount of interests in the areas of information technology, biotechnology, energy, and photonics. Significantly, recent developments in the synthetic and multicolor tuning methods have allowed easy access to upconversion nanoparticles with well-defined phase and size, core–shell structure, optical emission, and surface properties. The technological advances provide promising applications in sensitive biodetection and advanced bioimaging without many of the constraints associated with conventional optical biolabels. Despite the attractions, further progress in using upconversion processes has been largely hindered because upconversion nanoparticles are typically sensitized by Yb ions that only respond to narrowband NIR excitation centered at 980 nm. The absorption of 980 nm light by the water component in biological samples usually limits deep tissue imaging and induces potential thermal damages to cells and tissues. Excitation of conventional upconversion nanoparticles at other wavelengths has been proposed to minimize the effect of water absorption. But the use of this technique is limited mainly by the largely sacrificed excitation efficiency. Efforts have also been devoted to tuning the NIR response of photon upconversion through integration of various sensitizers such as metal ions (e.g.; Nd, V or Cr) and organic dyes. The progress has resulted in visible emission by NIR excitation in the 700–900 nm range where the transparency of biological samples is maximal. However, upconversion emission across a broad range of spectra in these systems have not been demonstrated largely owing to the uncontrollable nonradiative processes. Herein, we describe a novel design, based on nanostructural engineering to separate unwanted electronic transitions for constructing a new class of materials displaying tunable upconversion emissions spanning from UV to the visible spectral region by single wavelength excitation at 808 nm. We also show that these nanoparticles can surpass the constraints associated with conventional upconversion nanoparticles for biological studies. The nanostructure design for management of energy transitions is depicted in Figure 1. A core–shell–shell nanoparticle platform is used to host light-harvesting, upconvert-

Discovery of a Potent, Covalent BTK Inhibitor for B-Cell Lymphoma

BTK is a member of the TEC family of non-receptor tyrosine kinases whose deregulation has been implicated in a variety of B-cell-related diseases. We have used structure-based drug design in conjunction with kinome profiling and cellular assays to develop a potent, selective, and irreversible BTK kinase inhibitor, QL47, which covalently modifies Cys481. QL47 inhibits BTK kinase activity with an IC50 of 7 nM, inhibits autophosphorylation of BTK on Tyr223 in cells with an EC50 of 475 nM, and inhibits phosphorylation of a downstream effector PLCγ2 (Tyr759) with an EC50 of 318 nM. In Ramos cells QL47 induces a G1 cell cycle arrest that is associated with pronounced degradation of BTK protein. QL47 inhibits the proliferation of B-cell lymphoma cancer cell lines at submicromolar concentrations.

Nanocomposite-strengthened dissolving microneedles for improved transdermal delivery to human skin

Delivery of drugs and biomolecules into skin has significant advantages. To achieve this, herein, a nanomaterial-strengthened dissolving microneedle patch for transdermal delivery is reported. The patch comprises thousands of microneedles, which are composed of dissolving polymers, nanomaterials, and drug/biomolecules in their interior. With the addition of nanomaterials, the mechanical property of generally weak dissolving polymers can be dramatically improved without sacrificing dissolution rate within skin. In this experiments, layered double hydroxides (LDH) nanoparticles are incorporated into sodium carboxymethylcellulose (CMC) to form a nanocomposite. The results show that, by adding 5 wt% of LDH nanoparticles into CMC, the mechanical strength significantly increased. Small and densely packed CMC-LDH microneedles penetrate human and pig skin more reliably than pure CMC ones and attractively the nanocomposite-strengthened microneedles dissolve in skin and release payload within only 1 min. Finally, the application of using the nanocomposite-strengthened microneedle arrays is tested for in vivo vaccine delivery and the results show that significantly stronger antibody response could be induced when compared with subcutaneous injection. These data suggest that nanomaterials could be useful for fabricating densely packed and small polymer microneedles that have robust mechanical properties and rapid dissolution rates and therefore potential use in clinical applications.

Discovery of a BTK/MNK dual inhibitor for lymphoma and leukemia.

Bruton’s tyrosine kinase (BTK) kinase is a member of the TEC kinase family and is a key regulator of the B-cell receptor (BCR)-mediated signaling pathway. It is important for B-cell maturation, proliferation, survival and metastasis. Pharmacological inhibition of BTK is clinically effective against a variety of B-cell malignances, such as mantle cell lymphoma, chronic lymphocytic leukemia (CLL), acute myeloid leukemia (AML) and activated B-cell–diffuse large B-cell lymphoma. MNK kinase is one of the key downstream regulators in the RAF–MEK–ERK signaling pathway and controls protein synthesis via regulating the activity of eIF4E. Inhibition of MNK activity has been observed to moderately inhibit the proliferation of AML cells. Through a structure-based drug-design approach, we have discovered a selective and potent BTK/MNK dual kinase inhibitor (QL-X-138), which exhibits covalent binding to BTK and noncovalent binding to MNK. Compared with the BTK kinase inhibitor (PCI-32765) and the MNK kinase inhibitor (cercosporamide), QL-X-138 enhanced the antiproliferative efficacies in vitro against a variety of B-cell cancer cell lines, as well as AML and CLL primary patient cells, which respond moderately to BTK inhibitor in vitro. The agent can effectively arrest the growth of lymphoma and leukemia cells at the G0–G1 stage and can induce strong apoptotic cell death. These primary results demonstrate that simultaneous inhibition of BTK and MNK kinase activity might be a new therapeutic strategy for B-cell malignances.

A Diamond Nanoneedle Array for Potential High-Throughput Intracellular Delivery

A dense diamond nanoneedle array is capable of rapidly and conveniently delivering fluorescent probe and drug molecules to a large number of cells. This simple approach paves the way for potential high-throughput delivery of genes, drugs, and fluorescent probes into cells without endocytosis.

Ibrutinib selectively and irreversibly targets EGFR (L858R, Del19) mutant but is moderately resistant to EGFR (T790M) mutant NSCLC Cells

Through comprehensive comparison study, we found that ibrutinib, a clinically approved covalent BTK kinase inhibitor, was highly active against EGFR (L858R, del19) mutant driven NSCLC cells, but moderately active to the T790M ‘gatekeeper’ mutant cells and not active to wild-type EGFR NSCLC cells. Ibrutinib strongly affected EGFR mediated signaling pathways and induced apoptosis and cell cycle arrest (G0/G1) in mutant EGFR but not wt EGFR cells. However, ibrutinib only slowed down tumor progression in PC-9 and H1975 xenograft models. MEK kinase inhibitor, GSK1120212, could potentiate ibrutinibs effect against the EGFR (L858R/T790M) mutation in vitro but not in vivo. These results suggest that special drug administration might be required to achieve best clinical response in the ongoing phase I/II clinical trial with ibrutinib for NSCLC.

Ibrutinib targets mutant-EGFR kinase with a distinct binding conformation.

Ibrutinib, a clinically approved irreversible BTK kinase inhibitor for Mantle Cell Lymphoma (MCL) and Chronic Lymphocytic Leukemia (CLL) etc, has been reported to be potent against EGFR mutant kinase and currently being evaluated in clinic for Non Small Cell Lung Cancer (NSCLC). Through EGFR wt/mutant engineered isogenic BaF3 cell lines we confirmed the irreversible binding mode of Ibrutinib with EGFR wt/mutant kinase via Cys797. However, comparing to typical irreversible EGFR inhibitor, such as WZ4002, the washing-out experiments revealed a much less efficient covalent binding for Ibrutinib. The biochemical binding affinity examination in the EGFR L858R/T790M kinase revealed that, comparing to more efficient irreversible inhibitor WZ4002 (Kd: 0.074 μM), Ibrutinib exhibited less efficient binding (Kd: 0.18 μM). An X-ray crystal structure of EGFR (T790M) in complex with Ibrutinib exhibited a unique DFG-in/c-Helix-out inactive binding conformation, which partially explained the less efficiency of covalent binding and provided insight for further development of highly efficient irreversible binding inhibitor for the EGFR mutant kinase. These results also imply that, unlike the canonical irreversible inhibitor, sustained effective concentration might be required for Ibrutinib in order to achieve the maximal efficacy in the clinic application against EGFR driven NSCLC.

Ibrutinib selectively targets FLT3-ITD in mutant FLT3-positive AML.

Ibrutinib (PCI-32765) is an irreversible BTK (Bruton’s tyrosine kinase) kinase inhibitor that has been extensively used as a tool compound to validate the role of BTK kinase in B cell related malignances. Ibrutinib has been shown in preclinical studies to inhibit the proliferation of diffuse large B-cell lymphoma cells, mantle cell lymphoma cells, chronic lymphocytic leukemia cells and multiple myeloma cells by blocking BTK kinase activity; ibrutinib was recently approved for the clinical application on mantle cell lymphoma and chronic lymphocytic leukemia cells. Ibrutinib has also exhibited anti-inflammatory effects in preclinical models. Recently, it has been reported that ibrutinib is also effective against epidermal growth factor receptor mutantpositive non-small cell lung cancers through inhibition of epidermal growth factor receptor kinase activities. In addition, there is evidence showing that BTK is also an important target for Acute Myeloid Leukemia (AML). Despite the evidence that BTK knockdown impaired AML cancer cell growth, which suggested that BTK was important for AML cell proliferation, BTK kinase inhibition through use of a small molecule inhibitor like ibrutinib led only to moderate inhibition of proliferation of U937 cells with no apparent activity against other AML cell lines such as HL-60, TF-1 and THP-1. To further investigate the potency and activity of ibrutinib against AML, we screened a panel of AML cell lines spanning M0–M7 disease stages. Interestingly, we found that only FLT3-internal tandem duplication (ITD) mutant AML cell lines (MOLM13, MOLM14 and MV4-11) were sensitive to ibrutinib (Figure 1a and Supplementary Table 1). This is similar to what has been observed with the highly

A monofunctional platinum(II)-based anticancer agent from a salicylanilide derivative: Synthesis, antiproliferative activity, and transcription inhibition

Cationic monofunctional platinum(II)-based anticancer agents with a general formula of cis-[Pt(NH3)2(N-donor)Cl](+) have recently drawn significant attention due to their unique mode of action, distinctive anticancer spectrum, and promising antitumor activity both in vitro and in vivo. Understanding the mechanism of action of novel monofunctional platinum compounds through rational drug design will aid in the further development of active agents. In this study, we synthesized and evaluated a monofunctional platinum-based anticancer agent SA-Pt containing a bulky salicylanilide moiety. The antiproliferative activity of SA-Pt was close to that of cisplatin. Mechanism studies revealed that SA-Pt entered HeLa cells more efficiently than cisplatin, blocked the cell cycle at the S-phase, and induced apoptosis. The compound bound to DNA as effectively as cisplatin, but did not block RNA polymerase II-mediated transcription as strongly as cisplatin, indicating that once the compound formed Pt-DNA lesions, the salicylanilide group was more easily recognized and removed. This study not only enriches the family of monofunctional platinum-based anticancer agents but also guides the design of more potent monofunctional platinum complexes.

Simultaneous inhibition of Vps34 kinase would enhance PI3Kδ inhibitor cytotoxicity in the B-cell malignancies.

PI3Kδ has been found to be over-expressed in B-Cell-related malignancies. Despite the clinical success of the first selective PI3Kδ inhibitor, CAL-101, inhibition of PI3Kδ itself did not show too much cytotoxic efficacy against cancer cells. One possible reason is that PI3Kδ inhibition induced autophagy that protects the cells from death. Since class III PI3K isoform PIK3C3/Vps34 participates in autophagy initiation and progression, we predicted that a PI3Kδ and Vps34 dual inhibitor might improve the anti-proliferative activity observed for PI3Kδ-targeted inhibitors. We discovered a highly potent ATP-competitive PI3Kδ/Vps34 dual inhibitor, PI3KD/V-IN-01, which displayed 10-1500 fold selectivity over other PI3K isoforms and did not inhibit any other kinases in the kinome. In cells, PI3KD/V-IN-01 showed 30-300 fold selectivity between PI3Kδ and other class I PI3K isoforms. PI3KD/V-IN-01 exhibited better anti-proliferative activity against AML, CLL and Burkitt lymphoma cell lines than known selective PI3Kδ and Vps34 inhibitors. Interestingly, we observed FLT3-ITD AML cells are more sensitive to PI3KD/V-IN-01 than the FLT3 wt expressing cells. In AML cell inoculated xenograft mouse model, PI3KD/V-IN-01 exhibited dose-dependent anti-tumor growth efficacies. These results suggest that dual inhibition of PI3Kδ and Vps34 might be a useful approach to improve the PI3Kδ inhibitors anti-tumor efficacy.