The anti-esophageal cancer cell activity by a novel tyrosine/phosphoinositide kinase inhibitor PP121

Novel miRNA-inducing drugs enable differentiation of retinoic acid-resistant neuroblastoma cells

Tumor cell heterogeneity in neuroblastoma, a pediatric cancer arising from neural crest-derived progenitor cells, poses a significant clinical challenge. In particular, unlike adrenergic (ADRN) neuroblastoma cells, mesenchymal (MES) cells are resistant to chemotherapy and retinoid therapy and thereby significantly contribute to relapses and treatment failures. Previous research suggested that overexpression or activation of miR-124, a neurogenic microRNA with tumor suppressor activity, can induce the differentiation of retinoic acid-resistant neuroblastoma cells. Leveraging our established screen for miRNA modulatory small molecules, we validated PP121, a dual inhibitor of tyrosine and phosphoinositide kinases, as a robust inducer of miR-124. A combination of PP121 and miR-132-inducing bufalin synergistically arrests proliferation, induces differentiation, and prolongs the survival of differentiated MES SK-N-AS cells for 8 weeks. RNA- seq and deconvolution analyses revealed a collapse of the ADRN core regulatory circuitry (CRC) and the emergence of novel CRCs associated with chromaffin cells and Schwann cell precursors. Using a similar protocol, we differentiated and maintained other MES neuroblastoma, as well as glioblastoma cells, over 16 weeks. In conclusion, our novel protocol suggests a promising treatment for therapy-resistant cancers of the nervous system. Moreover, these long-lived, differentiated cells provide valuable models for studying mechanisms underlying differentiation, maturation, and senescence.

PP121, a dual inhibitor of tyrosine and phosphoinositide kinases, relieves airway hyperresponsiveness, mucus hypersecretion and inflammation in a murine asthma model

BACKGROUND

Tyrosine kinase and phosphoinositide kinase pathways play important roles in asthma formation. As a dual tyrosine and phosphoinositide kinase inhibitor, PP121 has shown anticancer efficacy in multiple tumors. However, the study of PP121 in pulmonary diseases is still limited. Herein, we investigated the therapeutic activities of PP121 in asthma treatment.

METHODS

Tension measurements and patch clamp recordings were made to investigate the anticontractile characteristics of PP121 in vitro. Then, an asthma mouse model was established to further explore the therapeutic characteristics of PP121 via measurement of respiratory system resistance, histological analysis and western blotting.

RESULTS

We discovered that PP121 could relax precontracted mouse tracheal rings (mTRs) by blocking certain ion channels, including L-type voltage-dependent Ca2+ channels (L-VDCCs), nonselective cation channels (NSCCs), transient receptor potential channels (TRPCs), Na+/Ca2+ exchangers (NCXs) and K+ channels, and accelerating calcium mobilization. Furthermore, PP121 relieved asthmatic pathological features, including airway hyperresponsiveness, systematic inflammation and mucus secretion, via downregulation of inflammatory factors, mucins and the mitogen-activated protein kinase (MAPK)/Akt signaling pathway in asthmatic mice.

CONCLUSION

In summary, PP121 exerts dual anti-contractile and anti-inflammatory effects in asthma treatment, which suggests that PP121 might be a promising therapeutic compound and shed new light on asthma therapy.

Autophagy induced by PP121 alleviates MSU crystal-induced acute gouty arthritis via inhibition of the NLRP3 inflammasome

Acute gouty arthritis (AGA) is a frequent self-limiting inflammatory condition produced by the deposition of monosodium urate (MSU) crystals in the joints and periarticular tissues of patients with hyperuricemia. However, no effective interventional measures currently exist for AGA. Pyroptosis, a kind of pro-inflammatory programmed cell death, plays a crucial role in MSU crystal-induced inflammation and represents a potential treatment target for AGA. Therefore, we determined the therapeutic benefits and mechanism of PP121, a pyroptosis-related compound, on AGA. First, we injected an MSU crystal solution intra-articularly into the left foot pad of C57BL/6 mice to create an AGA mouse model. Subsequent treatment with PP121 substantially decreased tissue damage, pro-inflammatory cytokine release, and inflammatory cell infiltration caused by MSU crystals in the ankle joint. Consistent with these observations, the beneficial effects of PP121 on AGA were cancelled in Beclin1+/-(Becn1+/-) mice. Furthermore, after PP121 treatment, super-resolution microscopy revealed a strong relationship between lysosome-connected membrane protein/light chain 3 positive vesicles and the nucleotide-binding domain of leucine-rich family pyrin domain-containing 3 (NLPR3), demonstrating that PP121 promotes phagocytosis of the NLPR3 inflammasome. In summary, PP121-mediated autophagy can improve degradation of the NLRR3 inflammasome in AGA, which suggests the therapeutic potential of PP121 in AGA.

Efficacy of PP121 in primary and metastatic non‑small cell lung cancers

Tyrosine kinase inhibitors are a clinically standard treatment option for non-small cell lung cancers (NSCLCs), the leading cause of cancer-related deaths in the US. These targeted agents include first, second and third generation tyrosine kinase inhibitors; however, these lack clinical efficacy in the treatment of NSCLC due to intrinsic and acquired resistance. This resistance may be a result of genetic aberrations in oncogenic signaling mediators of divergent pathways. The present study aimed to investigate a novel dual tyrosine kinase and PI3K inhibitor, PP121, as a targeted agent in NSCLC cell lines. The present study co-cultured PP121 with healthy human astrocytes, a prevalent cell type located in the brain of NSCLC brain metastases. To date, few preclinical studies have examined the efficacy of PP121 as an anticancer agent, and to the best of my knowledge, no previous studies have previously evaluated its therapeutic potential in the treatment of NSCLC. To investigate the clinical heterogeneity of NSCLC, patient-derived adenocarcinoma (ADC) and squamous cell carcinoma (SCC) xenograft models were used, which exhibited epidermal growth factor receptor (EGFR) mutations and mesenchymal-epithelial transition (MET) factor amplifications. Notably, both EGFR and MET are known contributors to tyrosine kinase inhibitor resistance; thus, the aforementioned mutations and amplifications enabled the effects of PP121 to be evaluated in these solid tumors. In addition, a co-cultured model system using both NSCLC cells and astrocytes was employed to assess the effects of PP121 on the invasion of ADC and SCC cells in a multicellular environment. Results of the present study demonstrated that PP121 exerted an antitumorigenic effect in the aforementioned model systems via downregulation of pharmacodynamic targets.

In situ activation of therapeutics through bioorthogonal catalysis

Bioorthogonal chemistry refers to any chemical reactions that can occur inside of living systems without interfering with native biochemical processes, which has become a promising strategy for modulating biological processes. The development of synthetic metal-based catalysts to perform bioorthogonal reactions has significantly expanded the toolkit of bioorthogonal chemistry for medicinal chemistry and synthetic biology. A wide range of homogeneous and heterogeneous transition metal catalysts (TMCs) have been reported, mediating different transformations such as cycloaddition reactions, as well as bond forming and cleaving reactions. However, the direct application of 'naked' TMCs in complex biological media poses numerous challenges, including poor water solubility, toxicity and catalyst deactivation. Incorporating TMCs into nanomaterials to create bioorthogonal nanocatalysts can solubilize and stabilize catalyst molecules, with the decoration of the nanocatalysts used to provide spatiotemporal control of catalysis. This review presents an overview of the advances in the creation of bioorthogonal nanocatalysts, highlighting different choice of nano-scaffolds, and the therapeutic and diagnostic applications.

Therapeutic Strategies Against Cancer Stem Cells in Esophageal Carcinomas

Cancer stem cells (CSCs) in esophageal cancer have a key role in tumor initiation, progression and therapy resistance. Novel therapeutic strategies to target CSCs are being tested, however, more in-depth research is necessary. Eradication of CSCs can result in successful therapeutic approaches against esophageal cancer. Recent evidence suggests that targeting signaling pathways, miRNA expression profiles and other properties of CSCs are important strategies for cancer therapy. Wnt/β-catenin, Notch, Hedgehog, Hippo and other pathways play crucial roles in proliferation, differentiation, and self-renewal of stem cells as well as of CSCs. All of these pathways have been implicated in the regulation of esophageal CSCs and are potential therapeutic targets. Interference with these pathways or their components using small molecules could have therapeutic benefits. Similarly, miRNAs are able to regulate gene expression in esophageal CSCs, so targeting self-renewal pathways with miRNA could be utilized to as a potential therapeutic option. Moreover, hypoxia plays critical roles in esophageal cancer metabolism, stem cell proliferation, maintaining aggressiveness and in regulating the metastatic potential of cancer cells, therefore, targeting hypoxia factors could also provide effective therapeutic modalities against esophageal CSCs. To conclude, additional study of CSCs in esophageal carcinoma could open promising therapeutic options in esophageal carcinomas by targeting hyper-activated signaling pathways, manipulating miRNA expression and hypoxia mechanisms in esophageal CSCs.

NVP-BSK805, an Inhibitor of JAK2 Kinase, Significantly Enhances the Radiosensitivity of Esophageal Squamous Cell Carcinoma in vitro and in vivo

Purpose

Radiotherapy is one major curative treatment modality for esophageal squamous cell carcinoma (ESCC) patients. This study aimed to find out small-molecular kinase inhibitors, which can significantly enhance the radiosensitivity of ESCC in vitro and in vivo.

Materials and Methods

Ninety-three kinase inhibitors were tested for their radiosensitizing effect in ESCC cells through high-content screening. The radiosensitizing effect of kinase inhibitors was investigated in vitro by detection of DNA double-strand breaks (DSBs) and clonogenic survival assay. By the establishment of xenograft tumor models in BALB/c nude mice, the radiosensitizing effect of kinase inhibitors was investigated in vivo.

Results

Among the 93 kinase inhibitors tested, we found NVP-BSK805, an inhibitor of JAK2 kinase, significantly radiosensitized ESCC cells through enhancing DSBs, inhibiting DNA damage repair and arresting cell cycle in G2/M or G0/G1 phase. After treatment with NVP-BSK805, ESCC cells showed decreased clonogenic survival and delayed tumor growth in vivo. JAK2 kinase was highly expressed in tumor tissues of ESCC patients, while rarely expressed in matched normal esophageal epithelial tissues. Survival analysis revealed JAK2 kinase as a prognostic factor of ESCC patients treated with chemoradiotherapy.

Conclusion

Our study discovered JAK2 kinase as an attractive target to enhance the radiosensitivity of ESCC cells in vitro and in vivo.

PP121 suppresses RANKL-Induced osteoclast formation in vitro and LPS-Induced bone resorption in vivo

Bone resorption, caused by osteoclasts (OCs), is important to bone homeostasis. The abnormalities of bone resorption may induce a series of diseases, including osteoarthritis, osteoporosis and aseptic peri-implant loosening. The latest research developed,a novel tyrosine and phosphoinositide kinase dual inhibitor, named PP121, inhibited Src in anaplastic thyroid carcinoma cell. However, the therapeutic function of PP121 on abnormal bone resorption is still uncertain. In the present study, we showed that PP121 could potently suppress osteoclast differentiation, osteoclast-specific gene expression and bone resorption via suppressing Src/MAPK (ERK and p38)/Akt-mediated NFATc1 induction in vitro. \It was found that PP121 could suppress the formation of osteoclasts from bone marrow macrophages (BMMs) without causing cytotoxicity, inhibit bone resorption and downregulate the mRNA level of osteoclast-specific markers, including calcitonin receptor (CTR), tartrate resistant acid phosphatase (TRAP), cathepsin K (CTSK), matrix metalloproteinase 3 (MMP3), Cellular oncogene fos (C-Fos) and nuclear factor of activated T-cells cytoplasmic 1 (NFATc1). Consistent with in vitro observation, we found that PP121 greatly ameliorated LPS-induced bone resorption. Our results provide promising evidence of the therapeutic potential of PP121 for osteolytic diseases related to excessive osteoclast-mediated bone resorption.

C6 ceramide motivates the anticancer sensibility induced by PKC412 in preclinical head and neck squamous cell carcinoma models

The purpose of this study was to evaluate the anti-head and neck squamous cell carcinoma (anti-HNSCC) cell activity by C6 ceramide and multikinase inhibitor PKC412. Experiments were performed on HNSCC cell lines (SQ20B and SCC-9) and primary human oral carcinoma cells. Results showed that PKC412 inhibited HNSCC cell proliferation without provoking apoptosis activation. Cotreatment of C6 ceramide significantly augmented PKC412-induced lethality in HNSCC cells. PKC412 decreased Akt-mammalian target of rapamycin (mTOR) activation in HNSCC cells, facilitated with cotreatment of C6 ceramide. In contrast, exogenous expression of a constitutively active Akt restored Akt-mTOR activation and attenuated lethality by the cotreatment. We propose that Mcl-1 is a primary resistance factor of PKC412. The cytotoxicity of PKC412 in HNSCC cells was potentiated with Mcl-1 short hairpin RNA knockdown, but was attenuated with Mcl-1 overexpression. Intriguingly, C6 ceramide downregulated Mcl-1 in HNSCC cells. In vivo, PKC412 oral administration inhibited SQ20B xenograft tumor growth in severe combined immunodeficient mice. The antitumor activity of PKC412 was further sensitized with coadministration of liposomal C6 ceramide. Together, we suggest that PKC412 could be further studied as a promising anti-HNSCC strategy, alone or in combination with C6 ceramide.

Pristimerin targeting NF-κB pathway inhibits proliferation, migration, and invasion in esophageal squamous cell carcinoma cells

Esophageal squamous cell carcinoma (ESCC) is one of the leading causes of cancer-related death with poor prognosis in China. Identifying novel targeted therapies in ESCC is urgently needed. The aberrant activation of NF-κB signalling pathway is critical for prognosis and recurrence of ESCC, which make it a potential target in the treatment of ESCC. Here, we found that pristimerin inhibited ESCC cell proliferation, migration, invasion, induced cell apoptosis, and eliminated cancer stem-like cells (CSCs). It also showed a synergistic effect on ESCC when combined with 5-fluorouracil (5-FU). Moreover, pristimerin potently inhibited the growth of ESCC xenograft in nude mice. The anti-ESCC effects of pristimerin were demonstrated to be associated with the inhibition of NF-κB pathway by suppressing tumour necrosis factor α (TNFα)-induced IκBα phosphorylation, p65 translocation, and NF-κB-dependent gene expression. This study provides an evidence for the development of pristimerin to be a new therapeutic agent for ESCC.

SIGNIFICANCE OF THE STUDY

Although several approaches including surgery, chemotherapy, and radiotherapy had been applied in the treatment of ESCC, more effective targeted chemotherapies are required to increase the survival rates of patients. This study suggested that inhibiting NF-κB signalling pathway could be an effective approach for the treatment of ESCC. Pristimerin, a potent NF-κB inhibitor, exerted potent anti-ESCC effects both in vitro and in vivo, which may be a promising therapeutic agent for ESCC.

Itraconazole-Induced Inhibition on Human Esophageal Cancer Cell Growth Requires AMPK Activation

We here evaluated the antiesophageal cancer cell activity by the antifungal drug itraconazole. Our results show that μg/mL concentrations of itraconazole potently inhibited survival and proliferation of established (TE-1 and Eca-109) and primary human esophageal cancer cells. Itraconazole activated AMPK signaling, which was required for subsequent esophageal cancer cell death. Pharmacologic AMPK inhibition, AMPKα1 shRNA, or dominant negative mutation (T172A) almost completely abolished itraconazole-induced cytotoxicity against esophageal cancer cells. Significantly, itraconazole induced AMPK-dependent autophagic cell death (but not apoptosis) in esophageal cancer cells. Furthermore, AMPK activation by itraconazole induced multiple receptor tyrosine kinases (RTKs: EGFR, PDGFRα, and PDGFRβ), lysosomal translocation, and degradation to inhibit downstream Akt activation. In vivo, itraconazole oral gavage potently inhibited Eca-109 tumor growth in SCID mice. It was yet ineffective against AMPKα1 shRNA-expressing Eca-109 tumors. The in vivo growth of the primary human esophageal cancer cells was also significantly inhibited by itraconazole administration. AMPK activation, RTK degradation, and Akt inhibition were observed in itraconazole-treated tumors. Together, itraconazole inhibits esophageal cancer cell growth via activating AMPK signaling. Mol Cancer Ther; 17(6); 1229-39. ©2018 AACR.

Mammalian Plakins, Giant Cytolinkers: Versatile Biological Functions and Roles in Cancer

Cancer is a highly lethal disease that is characterized by aberrant cell proliferation, migration, and adhesion, which are closely related to the dynamic changes of cytoskeletons and cytoskeletal-adhesion. These will further result in cell invasion and metastasis. Plakins are a family of giant cytolinkers that connect cytoskeletal elements with each other and to junctional complexes. With various isoforms composed of different domain structures, mammalian plakins are broadly expressed in numerous tissues. They play critical roles in many cellular processes, including cell proliferation, migration, adhesion, and signaling transduction. As these cellular processes are key steps in cancer development, mammalian plakins have in recent years attracted more and more attention for their potential roles in cancer. Current evidence shows the importance of mammalian plakins in various human cancers and demonstrates mammalian plakins as potential biomarkers for cancer. Here, we introduce the basic characteristics of mammalian plakins, review the recent advances in understanding their biological functions, and highlight their roles in human cancers, based on studies performed by us and others. This will provide researchers with a comprehensive understanding of mammalian plakins, new insights into the development of cancer, and novel targets for cancer diagnosis and therapy.

SC79 protects dopaminergic neurons from oxidative stress

Oxidative stress could lead to dopaminergic neuronal cell death. SC79 is a novel, selective and highly-efficient Akt activator. The current study tested its effect in dopaminergic neurons with oxidative stress. In both SH-SY5Y cells and primary murine dopaminergic neurons, pre-treatment with SC79 largely inhibited hydrogen peroxide (H2O2)-induced cell viability reduction, apoptosis and necrosis. SC79 activated Akt in the neuronal cells, which was required for its neuroprotection against H2O2. Inhibition of Akt activation (by MK-2206 or AT7867) or expression (by targeted short hairpin RNA) largely attenuated SC79-induced neuroprotection. Further, CRISPR-Cas9-mediated Akt1 knockout in SH-SY5Y cells abolished SC79-induced neuroprotective function against H2O2. Reversely, forced activation of Akt by the constitutively-active Akt1 mimicked SC79-induced anti-H2O2 activity. Together, we conclude that activation of Akt by SC79 protects dopaminergic neurons from H2O2.

Microtubule-Actin Crosslinking Factor 1 and Plakins as Therapeutic Drug Targets

Plakins are a family of seven cytoskeletal cross-linker proteins (microtubule-actin crosslinking factor 1 (MACF), bullous pemphigoid antigen (BPAG1) desmoplakin, envoplakin, periplakin, plectin, epiplakin) that network the three major filaments that comprise the cytoskeleton. Plakins have been found to be involved in disorders and diseases of the skin, heart, nervous system, and cancer that are attributed to autoimmune responses and genetic alterations of these macromolecules. Despite their role and involvement across a spectrum of several diseases, there are no current drugs or pharmacological agents that specifically target the members of this protein family. On the contrary, microtubules have traditionally been targeted by microtubule inhibiting agents, used for the treatment of diseases such as cancer, in spite of the deleterious toxicities associated with their clinical utility. The Research Collaboratory for Structural Bioinformatics (RCSB) was used here to identify therapeutic drugs targeting the plakin proteins, particularly the spectraplakins MACF1 and BPAG1, which contain microtubule-binding domains. RCSB analysis revealed that plakin proteins had 329 ligands, of which more than 50% were MACF1 and BPAG1 ligands and 10 were documented, clinically or experimentally, to have several therapeutic applications as anticancer, anti-inflammatory, and antibiotic agents.

GSK1059615 kills head and neck squamous cell carcinoma cells possibly via activating mitochondrial programmed necrosis pathway

This study tested the anti-head and neck squamous cell carcinoma (HNSCC) cell activity by GSK1059615, a novel PI3K and mTOR dual inhibitor. GSK1059615 inhibited survival and proliferation of established (SCC-9, SQ20B and A253 lines) and primary human HNSCC cells. GSK1059615 blocked PI3K-AKT-mTOR activation in HNSCC cells. Intriguingly, GSK1059615 treatment in HNSCC cells failed to provoke apoptosis, but induced programmed necrosis. The latter was tested by mitochondria depolarization, ANT-1-cyclophilin-D mitochondrial association and lactate dehydrogenase (LDH) release. Reversely, mPTP blockers (sanglifehrin A, cyclosporin A and bongkrekic acid) or cyclophilin-D shRNA dramatically alleviated GSK1059615-induced SCC-9 cell death. Further studies demonstrated that GSK1059615 i.p. injection suppressed SCC-9 tumor growth in nude mice, which was compromised with co-administration with cyclosporin A. Thus, targeting PI3K-AKT-mTOR pathway by GSK1059615 possibly provokes programmed necrosis pathway to kill HNSCC cells.

AT7867 Inhibits Human Colorectal Cancer Cells via AKT-Dependent and AKT-Independent Mechanisms

AKT is often hyper-activated in human colorectal cancers (CRC). This current study evaluated the potential anti-CRC activity by AT7867, a novel AKT and p70S6K1 (S6K1) dual inhibitor. We showed that AT7867 inhibited survival and proliferation of established (HT-29, HCT116 and DLD-1 lines) and primary human CRC cells. Meanwhile, it provoked caspase-dependent apoptosis in the CRC cells. Molecularly, AT7867 blocked AKT-S6K1 activation in CRC cells. Restoring AKT-S6K1 activation, via expression of a constitutively-active AKT1 ("ca-AKT1"), only partially attenuated AT7867-induced HT-29 cell death. Further studies demonstrated that AT7867 inhibited sphingosine kinase 1 (SphK1) activity to promote pro-apoptotic ceramide production in HT-29 cells. Such effects by AT7867 were independent of AKT inhibition. AT7867-indued ceramide production and subsequent HT-29 cell apoptosis were attenuated by co-treatment of sphingosine-1-phosphate (S1P), but were potentiated with the glucosylceramide synthase (GCS) inhibitor PDMP. In vivo, intraperitoneal injection of AT7867 inhibited HT-29 xenograft tumor growth in nude mice. AKT activation was also inhibited in AT7867-treated HT-29 tumors. Together, the preclinical results suggest that AT7867 inhibits CRC cells via AKT-dependent and -independent mechanisms.