Development of Furanopyrimidine-Based Orally Active Third-Generation EGFR Inhibitors for the Treatment of Non-Small Cell Lung Cancer.

The development of orally bioavailable, furanopyrimidine-based double-mutant (L858R/T790M) EGFR inhibitors is described. First, selectivity for mutant EGFR was accomplished by replacing the (S)-2-phenylglycinol moiety of 12 with either an ethanol or an alkyl substituent. Then, the cellular potency and physicochemical properties were optimized through insights from molecular modeling studies by implanting various solubilizing groups in phenyl rings A and B. Optimized lead 52 shows 8-fold selective inhibition of H1975 (EGFRL858R/T790M overexpressing) cancer cells over A431 (EGFRWT overexpressing) cancer cells; western blot analysis further confirmed EGFR mutant-selective target modulation inside the cancer cells by 52. Notably, 52 displayed in vivo antitumor effects in two different mouse xenograft models (BaF3 transfected with mutant EGFR and H1975 tumors) with TGI = 74.9 and 97.5% after oral administration (F = 27%), respectively. With an extraordinary kinome selectivity (S(10) score of 0.017), 52 undergoes detailed preclinical development.

Protective Effect of CXCR4 Antagonist DBPR807 against Ischemia-Reperfusion Injury in a Rat and Porcine Model of Myocardial Infarction: Potential Adjunctive Therapy for Percutaneous Coronary Intervention.

CXCR4 antagonists have been claimed to reduce mortality after myocardial infarction in myocardial infarction (MI) animals, presumably due to suppressing inflammatory responses caused by myocardial ischemia-reperfusion injury, thus, subsequently facilitating tissue repair and cardiac function recovery. This study aims to determine whether a newly designed CXCR4 antagonist DBPR807 could exert better vascular-protective effects than other clinical counterparts (e.g., AMD3100) to alleviate cardiac damage further exacerbated by reperfusion. Consequently, we find that instead of traditional continuous treatment or multiple-dose treatment at different intervals of time, a single-dose treatment of DBPR807 before reperfusion in MI animals could attenuate inflammation via protecting oxidative stress damage and preserve vascular/capillary density and integrity via mobilizing endothelial progenitor cells, leading to a desirable fibrosis reduction and recovery of cardiac function, as evaluated with the LVEF (left ventricular ejection fraction) in infarcted hearts in rats and mini-pigs, respectively. Thus, it is highly suggested that CXCR4 antagonists should be given at a single high dose prior to reperfusion to provide the maximal cardiac functional improvement. Based on its favorable efficacy and safety profiles indicated in tested animals, DBPR807 has a great potential to serve as an adjunctive medicine for percutaneous coronary intervention (PCI) therapies in acute MI patients.

Discovery of Potential Neuroprotective Agents against Paclitaxel-Induced Peripheral Neuropathy.

Chemotherapy-induced neurotoxicity is a common adverse effect of cancer treatment. No medication has been shown to be effective in the prevention or treatment of chemotherapy-induced neurotoxicity. Using minoxidil as an initial template for structural modifications in conjunction with an in vitro neurite outgrowth assay, an image-based high-content screening platform, and mouse behavior models, an effective neuroprotective agent CN016 was discovered. Our results showed that CN016 could inhibit paclitaxel-induced inflammatory responses and infiltration of immune cells into sensory neurons significantly. Thus, the suppression of proinflammatory factors elucidates, in part, the mechanism of action of CN016 on alleviating paclitaxel-induced peripheral neuropathy. Based on excellent efficacy in improving behavioral functions, high safety profiles (MTD > 500 mg/kg), and a large therapeutic window (MTD/MED > 50) in mice, CN016 might have great potential to become a peripherally neuroprotective agent to prevent neurotoxicity caused by chemotherapeutics as typified by paclitaxel.

DBPR108, a novel dipeptidyl peptidase-4 inhibitor with antihyperglycemic activity.

AIMS: Dipeptidyl peptidase 4 (DPP-4) is a valid molecular drug target from which its inhibitors have been developed as medicines for treating diabetes. The present study evaluated a new synthetic DPP-4-specific inhibitor of small molecule DBPR108 for pharmacology and pharmacokinetic profiles. MAIN METHODS: DBPR108 of various doses was orally administered to rats, diabetic mice, and dogs and the systemic circulating DPP-4 activities in the animals were measured to demonstrate the pharmacological mechanisms of action via DPP-4 inhibition. Upon an oral administration of DBPR108, the serum active GLP-1 and insulin levels of the rats challenged with an oral glucose ingestion were measured. Oral glucose tolerance test in diet-induced obese mice was performed to examine if DBPR108 increases the glucose tolerability in animals. KEY FINDINGS: Orally administered DBPR108 inhibited the systemic plasma DPP-4 activities in rats, dogs and diabetic mice in a dose-dependent manner. DBPR108 caused elevated serum levels of active GLP-1 and insulin in the rats. DBPR108 dose-dependently increased the glucose tolerability in diet-induced obese (DIO) mice and, furthermore, DIO mice treated with DBPR108 (0.1 mg/kg) in combination with metformin (50 or 100 mg/kg) showed a prominently strong increase in the glucose tolerability. SIGNIFICANCE: DBPR108 is a novel DPP-4-selective inhibitor of small molecule that demonstrated potent in vivo pharmacological effects and good safety profiles in animals. DBPR108 is now a drug candidate being further developed in the clinical studies as therapeutics for treating diabetes.

A highly selective and potent CXCR4 antagonist for hepatocellular carcinoma treatment.

The CXC chemokine receptor type 4 (CXCR4) receptor and its ligand, CXCL12, are overexpressed in various cancers and mediate tumor progression and hypoxia-mediated resistance to cancer therapy. While CXCR4 antagonists have potential anticancer effects when combined with conventional anticancer drugs, their poor potency against CXCL12/CXCR4 downstream signaling pathways and systemic toxicity had precluded clinical application. Herein, BPRCX807, known as a safe, selective, and potent CXCR4 antagonist, has been designed and experimentally realized. In in vitro and in vivo hepatocellular carcinoma mouse models it can significantly suppress primary tumor growth, prevent distant metastasis/cell migration, reduce angiogenesis, and normalize the immunosuppressive tumor microenvironment by reducing tumor-associated macrophages (TAMs) infiltration, reprogramming TAMs toward an immunostimulatory phenotype and promoting cytotoxic T cell infiltration into tumor. Although BPRCX807 treatment alone prolongs overall survival as effectively as both marketed sorafenib and anti-PD-1, it could synergize with either of them in combination therapy to further extend life expectancy and suppress distant metastasis more significantly.

Molecular profiling of afatinib-resistant non-small cell lung cancer cells in vivo derived from mice.

Non-small-cell lung cancer (NSCLC) is a leading cause of cancer-related death worldwide. NSCLC patients with overexpressed or mutated epidermal growth factor receptor (EGFR) related to disease progression are treated with EGFR-tyrosine kinase inhibitors (EGFR-TKIs). Acquired drug resistance after TKI treatments has been a major focus for development of NSCLC therapies. This study aimed to establish afatinib-resistant cell lines from which afatinib resistance-associated genes are identified and the underlying mechanisms of multiple-TKI resistance in NSCLC can be further investigated. Nude mice bearing subcutaneous NSCLC HCC827 tumors were administered with afatinib at different dose intensities (5-100 mg/kg). We established three HCC827 sublines resistant to afatinib (IC50 > 1 µM) with cross-resistance to gefitinib (IC50 > 5 µM). cDNA microarray revealed several of these sublines shared 27 up- and 13 down-regulated genes. The mRNA expression of selective novel genes - such as transmembrane 4 L six family member 19 (TM4SF19), suppressor of cytokine signaling 2 (SOCS2), and quinolinate phosphoribosyltransferase (QPRT) - are responsive to afatinib treatments only at high concentrations. Furthermore, c-MET amplification and activations of a subset of tyrosine kinase receptors were observed in all three resistant cells. PHA665752, a c-MET inhibitor, remarkably increased the sensitivity of these resistant cells to afatinib (IC50 = 12-123 nM). We established afatinib-resistant lung cancer cell lines and here report genes associated with afatinib resistance in human NSCLC. These cell lines and the identified genes serve as useful investigational tools, prognostic biomarkers of TKI therapies, and promising molecule targets for development of human NSCLC therapeutics.

Discovery of a Furanopyrimidine-Based Epidermal Growth Factor Receptor Inhibitor (DBPR112) as a Clinical Candidate for the Treatment of Non-Small Cell Lung Cancer.

Epidermal growth factor receptor (EGFR)-targeted therapy in non-small cell lung cancer represents a breakthrough in the field of precision medicine. Previously, we have identified a lead compound, furanopyrimidine 2, which contains a (S)-2-phenylglycinol structure as a key fragment to inhibit EGFR. However, compound 2 showed high clearance and poor oral bioavailability in its pharmacokinetics studies. In this work, we optimized compound 2 by scaffold hopping and exploiting the potent inhibitory activity of various warhead groups to obtain a clinical candidate, 78 (DBPR112), which not only displayed a potent inhibitory activity against EGFRL858R/T790M double mutations but also exhibited tenfold potency better than the third-generation inhibitor, osimertinib, against EGFR and HER2 exon 20 insertion mutations. Overall, pharmacokinetic improvement through lead-to-candidate optimization yielded fourfold oral AUC better that afatinib along with F = 41.5%, an encouraging safety profile, and significant antitumor efficacy in in vivo xenograft models. DBPR112 is currently undergoing phase 1 clinical trial in Taiwan.

Development of Stem-Cell-Mobilizing Agents Targeting CXCR4 Receptor for Peripheral Blood Stem Cell Transplantation and Beyond.

The function of the CXCR4/CXCL12 axis accounts for many disease indications, including tissue/nerve regeneration, cancer metastasis, and inflammation. Blocking CXCR4 signaling with its antagonists may lead to moving out CXCR4+ cell types from bone marrow to peripheral circulation. We have discovered a novel series of pyrimidine-based CXCR4 antagonists, a representative (i.e., 16) of which was tolerated at a higher dose and showed better HSC-mobilizing ability at the maximal response dose relative to the approved drug 1 (AMD3100), and thus considered a potential drug candidate for PBSCT indication. Docking compound 16 into the X-ray crystal structure of CXCR4 receptor revealed that it adopted a spider-like conformation striding over both major and minor subpockets. This putative binding mode provides a new insight into CXCR4 receptor-ligand interactions for further structural modifications.

A Novel CXCR4 Antagonist CX549 Induces Neuroprotection in Stroke Brain.

C-X-C chemokine receptor type 4 (CXCR4) is a receptor for a pleiotropic chemokine CXCL12. Previous studies have shown that the acute administration of the CXCR4 antagonist AMD3100 reduced neuroinflammation in stroke brain and mobilized bone marrow hematopoietic stem cells (HSCs). The purpose of this study was to characterize the neuroprotective and neurotrophic effect of a novel CXCR4 antagonist CX549. We demonstrated that CX549 had a higher affinity for CXCR4 and was more potent than AMD3100 to inhibit CXCL12-mediated chemotaxis in culture. CX549 effectively reduced the activation of microglia and improved neuronal survival after injury in neuron/microglia cocultures. Early poststroke treatment with CX549 significantly improved behavioral function, reduced brain infarction, and suppressed the expression of inflammatory markers. Compared to AMD3100, CX549 has a higher affinity for CXCR4, is more efficient to mobilize HSCs for transplantation, and induces behavioral improvement. Our data support that CX549 is a potent anti-inflammatory agent, is neuroprotective against ischemic brain injury, and may have clinical implications for the treatment of stroke.

Stem cell mobilizers targeting chemokine receptor CXCR4: renoprotective application in acute kidney injury.

We have discovered a novel series of quinazoline-based CXCR4 antagonists. Of these, compound 19 mobilized CXCR4(+) cell types, including hematopoietic stem cells and endothelial progenitor cells, more efficiently than the marketed 1 (AMD3100) with subcutaneous administration at the same dose (6 mg/kg) in mice. This series of compounds thus provides a set of valuable tools to study diseases mediated by the CXCR4/SDF-1 axis, including myocardial infarction, ischemic stroke, and cancer metastasis. More importantly, treatment with compound 19 significantly lowered levels of blood urea nitrogen and serum creatinine in rats with renal ischemia-reperfusion injury, providing evidence for its therapeutic potential in preventing ischemic acute kidney injury. CXCR4 antagonists such as 19 might also be useful to increase circulating levels of adult stem cells, thereby exerting beneficial effects on damaged and/or inflamed tissues in diseases that currently are not treated by standard approaches.

Design and synthesis of tetrahydropyridothieno[2,3-d]pyrimidine scaffold based epidermal growth factor receptor (EGFR) kinase inhibitors: the role of side chain chirality and Michael acceptor group for maximal potency.

HTS hit 7 was modified through hybrid design strategy to introduce a chiral side chain followed by introduction of Michael acceptor group to obtain potent EGFR kinase inhibitors 11 and 19. Both 11 and 19 showed over 3 orders of magnitude enhanced HCC827 antiproliferative activity compared to HTS hit 7 and also inhibited gefitinib-resistant double mutant (DM, T790M/L858R) EGFR kinase at nanomolar concentration. Moreover, treatment with 19 shrinked tumor in nude mice xenograft model.

Antiangiogenic activities and cisplatin-combined antitumor activities of BPR0L075.

BACKGROUND: Antimitotic tubulin-binding BPR0L075 is structurally analogous to the vascular-disrupting combretastatin A-4. MATERIALS AND METHODS: In vitro/in vivo models of endothelial cells cultures, Matrigel plug assay, tumor-bearing nude mice, and murine leukemia cells-inoculated mice were utilized to evaluate BPR0L075 for antiangiogenic and antitumoral activity spectra. RESULTS: BPR0L075 concentration-dependently inhibited proliferation and migration of human umbilical vein endothelial cells (HUVECs), disrupted capillary tube formations of HUVECs and rat aorta endothelial cells, and suppressed in vivo VEGF-mediated angiogenesis in Matrigel plugs in mice. Besides inhibiting the colony growth of cancer cells, BPR0L075 suppressed growth of subcutaneously-xenografted human lung, colorectal, and cervical solid tumors in nude mice. Combination treatments of BPR0L075 plus cisplatin, compared to either agent alone, demonstrated a stronger growth inhibition against the tumor xenografts in nude mice and longer lifespan in the leukemia mice. CONCLUSION: BPR0L075 is an antitumoral and antiangiogenic agent and potentiates the anticancer activity of cisplatin.

(2S,4S)-1-[2-(1,1-dimethyl-3-oxo-3-pyrrolidin-1-yl-propylamino)acetyl]-4-fluoro-pyrrolidine-2-carbonitrile: a potent, selective, and orally bioavailable dipeptide-derived inhibitor of dipeptidyl peptidase IV.

A series of 2-[3-[2-[(2S)-2-cyano-1-pyrrolidinyl]-2-oxoethylamino]-3-methyl-1-oxobutyl]-based DPP-IV inhibitors with various monocyclic amines were synthesized. The structure-activity relationships (SAR) led to the discovery of potent DPP-IV inhibitors, having IC(50) values of <100 nM with excellent selectivity over the closely related enzymes, DPP-II, DPP8, DPP9 and FAP (IC(50)>20 microM). Of these compounds, the analogues 12a, 12h and 12i exhibited a long-lasting ex vivo DPP-IV inhibition in rats.

Intravenous paclitaxel against metastasis of human gastric tumors of diffuse type.

PURPOSE: Gastric cancer is one of the leading cancerous diseases worldwide. It is diagnosed often at the advanced stage for which chemotherapy is the main treatment option. The prognosis remains poor for metastatic, especially the diffuse type, gastric cancers. We investigated the efficacy of intravenously administered paclitaxel treating metastases of locally disseminated gastric tumors of diffuse type. METHODS: Transfection of green fluorescent proteins (GFP)-expressing plasmid into human gastric cancer MKN45 cells of diffuse type was performed, and MKN45-GFP cells constitutively expressing GFP were isolated. The MKN45-GFP cells were orthotopically inoculated into the mouse peritoneal cavity, and tumor growth and organ metastases were monitored. Liver metastases were harvested, re-inoculated, monitored for liver metastases again, and harvested for further inoculation. This in vivo selection procedure was repeated to isolate a subline with high metastatic abilities demonstrated by in vitro invasion abilities using Transwell((R)) system. By visualizing the GFP-expressing tumors, the effects of intravenously administered paclitaxel against the growing peritoneally disseminated and metastasized tumors in nude mice without laparotomy were measured. RESULTS: An in vivo selected gastric cancer cell line MKN45-GFP-ip4 with high metastatic ability was established. Its invasion ability was inhibited by paclitaxel treatments in vitro. The growths of metastatic and intraperitoneally disseminated MKN45-GFP-ip4 tumors were significantly suppressed by intravenous paclitaxel treatments in nude mice. CONCLUSIONS: We found that intravenous paclitaxel is active against the metastases of human gastric cancer of peritoneal diffuse type, which warrants further investigations on optimizing the perioperative regimens with intravenous paclitaxel therapy for gastric cancer in patients.

Novel trans-2-aryl-cyclopropylamine analogues as potent and selective dipeptidyl peptidase IV inhibitors.

A series of trans-2-aryl-cyclopropylamine derived compounds were synthesized and evaluated their biological activities against DPP-IV. The structure-activity relationships (SAR) led to the discovery of novel series of DPP-IV inhibitors, having IC(50) values of <100 nM with excellent selectivity over the closely related enzymes, DPP8, DPP-II and FAP. The studies identified a potent and selective DPP-IV inhibitor 24b, which exhibited the ability to both significantly inhibit plasma DPP-IV activity in rats and improve glucose tolerance in lean mice and diet induced obese mice.

Rational design and synthesis of potent and long-lasting glutamic acid-based dipeptidyl peptidase IV inhibitors.

A series of (2S)-cyanopyrrolidines with glutamic acid derivatives at the P2 site have been prepared and evaluated as inhibitors of dipeptidyl peptidase IV (DPP-IV). The structure-activity relationships (SAR) led to the discovery of potent 3-substituted glutamic acid analogues, providing enhanced chemical stability and excellent selectivity over the closely related enzymes, DPP8, DPP-II and FAP. Compound 13f exhibited the ability to both significantly decrease the glucose excursion and inhibit plasma DPP-IV activity.