Novel multi-targeted ErbB family inhibitor afatinib blocks EGF-induced signaling and induces apoptosis in neuroblastoma

Pervasive aggregation and depletion of host and viral proteins in response to cysteine-reactive electrophilic compounds

Protein homeostasis is tightly regulated, with damaged or misfolded proteins quickly eliminated by the proteasome and autophagosome pathways. By co-opting these processes, targeted protein degradation technologies enable pharmacological manipulation of protein abundance. Recently, cysteine-reactive molecules have been added to the degrader toolbox, which offer the benefit of unlocking the therapeutic potential of 'undruggable' protein targets. The proteome-wide impact of these molecules remains to be fully understood and given the general reactivity of many classes of cysteine-reactive electrophiles, on- and off-target effects are likely. Using chemical proteomics, we identified a cysteine-reactive small molecule degrader of the SARS-CoV-2 non- structural protein 14 (nsp14), which effects degradation through direct modification of cysteines in both nsp14 and in host chaperones together with activation of global cell stress response pathways. We find that cysteine-reactive electrophiles increase global protein ubiquitylation, trigger proteasome activation, and result in widespread aggregation and depletion of host proteins, including components of the nuclear pore complex. Formation of stress granules was also found to be a remarkably ubiquitous cellular response to nearly all cysteine-reactive compounds and degraders. Collectively, our study sheds light on complexities of covalent target protein degradation and highlights untapped opportunities in manipulating and characterizing proteostasis processes via deciphering the cysteine-centric regulation of stress response pathways.

Difluoromethylornithine (DFMO) and Neuroblastoma: A Review

Neuroblastoma is a type of cancer that affects the sympathetic nervous system and is the most common extracranial solid tumor in children. Difluoromethylornithine (DFMO) is a drug that has shown promise as a treatment option for high-risk neuroblastoma. This review aims to provide an overview of the current research on the use of DFMO in neuroblastoma treatment. The review includes a discussion of the mechanisms of action of DFMO, as well as its potential for use in combination with other treatments such as chemotherapy and immunotherapy. The review also examines the current clinical trials involving DFMO in high-risk neuroblastoma patients and provides insights into the challenges and future directions for the use of DFMO in neuroblastoma treatment. Overall, the review highlights the potential of DFMO as a promising therapy for neuroblastoma and highlights the need for further research to fully understand its potential benefits and limitations.

Chitosan Oligosaccharide Prevents Afatinib-Induced Barrier Disruption and Chloride Secretion through Modulation of AMPK, PI3K/AKT, and ERK Signaling in T84 Cells

Diarrhea is an important adverse effect of epidermal growth factor receptor-tyrosine kinase inhibitors, especially afatinib. Novel antidiarrheal agents are needed to reduce epidermal growth factor receptor-tyrosine kinase inhibitor-associated diarrhea to improve the quality of life and treatment outcome in cancer patients. This study aimed to investigate the anti-diarrheal activity of chitosan oligosaccharide against afatinib-induced barrier disruption and chloride secretion in human intestinal epithelial cells (T84 cells). Chitosan oligosaccharide (100 μg/mL) prevented afatinib-induced barrier disruption determined by changes in transepithelial electrical resistance and FITC-dextran flux in the T84 cell monolayers. In addition, chitosan oligosaccharide prevented afatinib-induced potentiation of cAMP-induced chloride secretion measured by short-circuit current analyses in the T84 cell monolayers. Chitosan oligosaccharide induced the activation of AMPK, a positive regulator of epithelial tight junction and a negative regulator of cAMP-induced chloride secretion. Moreover, chitosan oligosaccharide partially reversed afatinib-induced AKT inhibition without affecting afatinib-induced ERK inhibition via AMPK-independent mechanisms. Collectively, this study reveals that chitosan oligosaccharide prevents the afatinib-induced diarrheal activities in T84 cells via both AMPK-dependent and AMPK-independent mechanisms. Chitosan oligosaccharide represents a promising natural polymer-derived compound for further development of treatment for afatinib-associated diarrheas.

Synthetic Heterocyclic Derivatives as Kinase Inhibitors Tested for the Treatment of Neuroblastoma

In the last few years, small molecules endowed with different heterocyclic scaffolds have been developed as kinase inhibitors. Some of them are being tested at preclinical or clinical levels for the potential treatment of neuroblastoma (NB). This disease is the most common extracranial solid tumor in childhood and is responsible for 10% to 15% of pediatric cancer deaths. Despite the availability of some treatments, including the use of very toxic cytotoxic chemotherapeutic agents, high-risk (HR)-NB patients still have a poor prognosis and a survival rate below 50%. For these reasons, new pharmacological options are urgently needed. This review focuses on synthetic heterocyclic compounds published in the last five years, which showed at least some activity on this severe disease and act as kinase inhibitors. The specific mechanism of action, selectivity, and biological activity of these drug candidates are described, when established. Moreover, the most remarkable clinical trials are reported. Importantly, kinase inhibitors approved for other diseases have shown to be active and endowed with lower toxicity compared to conventional cytotoxic agents. The data collected in this article can be particularly useful for the researchers working in this area.

Bioinformatics Analysis of Neuroblastoma miRNA Based on GEO Data

Objective

To analyze the changes in downstream genes, signaling pathways, and proteins based on the difference of microRNA (miRNA) expression in neuroblastoma (NB).

Methods

GSE128004 second-generation sequencing expression data were downloaded from GEO, and Limma package of R language was used to analyze differential expression, and a volcano map and heat map were drawn; the target genes corresponding to the differential miRNA were found using the miWalk web tool, and GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) were performed. The key genes were identified and verified in the TCGA database.

Results

A total of 34 differentially expressed miRNAs were screened out. Among them, 22 up-regulated miRNAs predicted 1163 target genes and 12 down-regulated miRNAs predicted 1474 target genes. Target genes were enriched and analyzed by KEGG to find the FOXO signal pathway, mTOR signal pathway, AMPK signal pathway, and other signal pathways. After GO analysis, axon formation, regulation of chemical synaptic transmitters, regulation of nerve synapses, regulation of cross-synaptic signals, and other physiological processes were assessed. A total of 16 key genes were obtained by PPI analysis, and the survival analysis of TP53 and ATM genes verified in the TCGA database showed statistical significance.

Conclusion

The 34 differential miRNAs may be related to the occurrence and development of NB. TP53 and ATM are related to the prognosis of NB. The role and mechanism of TP53 and ATM in NB need to be further verified.

Determining the effects of trastuzumab, cetuximab and afatinib by phosphoprotein, gene expression and phenotypic analysis in gastric cancer cell lines

BACKGROUND

Gastric cancer is the fifth most frequently diagnosed cancer and the third leading cause of cancer death worldwide. The molecular mechanisms of action for anti-HER-family drugs in gastric cancer cells are incompletely understood. We compared the molecular effects of trastuzumab and the other HER-family targeting drugs cetuximab and afatinib on phosphoprotein and gene expression level to gain insights into the regulated pathways. Moreover, we intended to identify genes involved in phenotypic effects of anti-HER therapies.

METHODS

A time-resolved analysis of downstream intracellular kinases following EGF, cetuximab, trastuzumab and afatinib treatment was performed by Luminex analysis in the gastric cancer cell lines Hs746T, MKN1, MKN7 and NCI-N87. The changes in gene expression after treatment of the gastric cancer cell lines with EGF, cetuximab, trastuzumab or afatinib for 4 or 24 h were analyzed by RNA sequencing. Significantly enriched pathways and gene ontology terms were identified by functional enrichment analysis. Furthermore, effects of trastuzumab and afatinib on cell motility and apoptosis were analyzed by time-lapse microscopy and western blot for cleaved caspase 3.

RESULTS

The Luminex analysis of kinase activity revealed no effects of trastuzumab, while alterations of AKT1, MAPK3, MEK1 and p70S6K1 activations were observed under cetuximab and afatinib treatment. On gene expression level, cetuximab mainly affected the signaling pathways, whereas afatinib had an effect on both signaling and cell cycle pathways. In contrast, trastuzumab had little effects on gene expression. Afatinib reduced average speed in MKN1 and MKN7 cells and induced apoptosis in NCI-N87 cells. Following treatment with afatinib, a list of 14 genes that might be involved in the decrease of cell motility and a list of 44 genes that might have a potential role in induction of apoptosis was suggested. The importance of one of these genes (HBEGF) as regulator of motility was confirmed by knockdown experiments.

CONCLUSIONS

Taken together, we described the different molecular effects of trastuzumab, cetuximab and afatinib on kinase activity and gene expression. The phenotypic changes following afatinib treatment were reflected by altered biological functions indicated by overrepresentation of gene ontology terms. The importance of identified genes for cell motility was validated in case of HBEGF.

Nolz1 expression is required in dopaminergic axon guidance and striatal innervation

Midbrain dopaminergic (DA) axons make long longitudinal projections towards the striatum. Despite the importance of DA striatal innervation, processes involved in establishment of DA axonal connectivity remain largely unknown. Here we demonstrate a striatal-specific requirement of transcriptional regulator Nolz1 in establishing DA circuitry formation. DA projections are misguided and fail to innervate the striatum in both constitutive and striatal-specific Nolz1 mutant embryos. The lack of striatal Nolz1 expression results in nigral to pallidal lineage conversion of striatal projection neuron subtypes. This lineage switch alters the composition of secreted factors influencing DA axonal tract formation and renders the striatum non-permissive for dopaminergic and other forebrain tracts. Furthermore, transcriptomic analysis of wild-type and Nolz1^−/− mutant striatal tissue led to the identification of several secreted factors that underlie the observed guidance defects and proteins that promote DA axonal outgrowth. Together, our data demonstrate the involvement of the striatum in orchestrating dopaminergic circuitry formation.

The mechanisms regulating midbrain dopaminergic innervation during development are unclear. Here, the authors showed that Nolz1 is required for axonal guidance of dopaminergic neurons during embryonic development of the mouse brain.

Serine peptidase inhibitor Kazal type III (SPINK3) promotes BRL-3A cell proliferation by targeting the PI3K-AKT signaling pathway

The serine protease inhibitor, Kazal type III (SPINK3), is a trypsin inhibitor associated with liver disease, which highly overexpresses in a variety of cancers. In one of our previous studies of our laboratory, Spink3 was observed to be significantly upregulated in rat liver regeneration (LR) via a gene expression profile. For the current study, rat hepatocyte BRL-3A cells were treated by gene addition/interference, and the addition of the exogenous rat recombinant protein SPINK3. It was revealed that both the overexpression of endogenous Spink3 and addition of exogenous rat recombinant SPINK3 (rrSPINK3) significantly promoted the cell proliferation of BRL-3A cells, whereas cell proliferation was inhibited when Spink3 was interfered. Furthermore, quantitative reverse transcription polymerase chain reaction and western blot results revealed that three signaling pathways, including extracellular-signal-regulated kinase 1/2 (ERK1/2), Janus kinase (JAK)-signal transducer and activator of transcription (STAT), and phosphatidylinositol-3-kinase (PI3K)-protein kinase B (AKT), as well as their related genes, were altered following endogenous Spink3 addition/interference. Also, the PI3K-AKT and SRC-p38 pathways and their related genes were modified following exogenous SPINK3 treatment. Among them, the common signaling pathway was PI3K-AKT pathway. We concluded that SPINK3 could activate the PI3K-AKT pathway by enhancing the expression of AKT1 to regulate the proliferation of BRL-3A cells. This study may contribute to shedding light on the potential mechanisms of SPINK3 that regulate the proliferation of BRL-3A cells.

Dual Targeting of ERBB2/ERBB3 for the Treatment of SLC3A2-NRG1-Mediated Lung Cancer

We characterized the SLC3A2-NRG1 fusion gene in non-small cell lung cancer (NSCLC) and established an effective therapy for patients with SLC3A2-NRG1 fusion-positive cancer. The SLC3A2-NRG1 fusion product was composed of the SLC3A2 transmembrane domain and the EGF-like domain of the neuregulin 1 (NRG1) protein. The NRG1 family is classified as a ligand of the ERBB family. We identified ERBB3 and ERBB4 in the ERBB family as binding partners of the SLC3A2-NRG1 fusion protein via ligand and receptor binding assays. We confirmed that SLC3A2-NRG1 increased formation of a heterocomplex of ERBB3 with ERBB2. Activation of the ERBB2-ERBB3 heterocomplex by SLC3A2-NRG1 increased colony formation and tumor growth through PI3K-AKT and MAP kinase. The specific siRNAs for ERBB2 and ERBB3, pertuzumab, lumretuzumab, and afatinib all decreased ERBB2-ERBB3 heterocomplex formation, phosphorylation of each protein, and their downstream signaling. In addition, single treatment with pertuzumab, lumretuzumab, or afatinib decreased tumor volume and weight, whereas combination treatment with these drugs and taxol enhanced generation of cleaved caspase 3, PARP, and TUNEL-positive cells compared with each single treatment. Thus, the SLC3A2-NRG1 fusion gene plays an important role in lung cancer cell proliferation and tumor growth by promoting generation of the ERBB2-ERBB3 heterocomplex, its phosphorylation, and activation of the PI3K/ERK/mTOR signaling pathway. Inhibition of either ERBB2 or ERBB3 alone did not completely shut down downstream signaling of ERBB2 and ERBB3; however, inhibition of both ERBB2 and ERBB3 blocked downstream signaling activated by SLC3A2-NRG1 fusion. ERBB2 and ERBB3 might be promising targets for treatment of SLC3A2-NRG1-positive tumors. Mol Cancer Ther; 17(9); 2024-33. ©2018 AACR.

PEST-containing nuclear protein mediates the proliferation, migration, and invasion of human neuroblastoma cells through MAPK and PI3K/AKT/mTOR signaling pathways

Background

PEST-containing nuclear protein (PCNP), a novel nuclear protein, is involved in cell proliferation and tumorigenesis. However, the precise mechanism of action of PCNP in the process of tumor growth has not yet been fully elucidated.

Methods

ShRNA knockdown and overexpression of PCNP were performed in human neuroblastoma cells. Tumorigenic and metastatic effects of PCNP were examined by tumor growth, migration, and invasion assays in vitro, as well as xenograft tumor assay in vivo.

Results

PCNP over-expression decreased the proliferation, migration, and invasion of human neuroblastoma cells and down-regulation of PCNP showed reverse effects. PCNP over-expression increased protein expressions of cleaved caspase-3, cleaved caspase-8, cleaved caspase-9, and cleaved poly adenosine diphosphate-ribose polymerase, as well as ratios of B-cell lymphoma-2 (Bcl-2)-associated X protein/Bcl-2 and Bcl-2-associated death promoter/B-cell lymphoma-extra large in human neuroblastoma cells, however PCNP knockdown exhibited reverse trends. PCNP over-expression increased phosphorylations of extracellular signal-regulated protein kinase 1/2, p38, c-Jun N-terminal kinase, as well as decreased phosphorylations of phosphatidylinositol 3-kinase (PI3K), Akt, and mammalian target of rapamycin (mTOR), nevertheless PCNP knockdown exhibited opposite effects. Furthermore, PCNP over-expression significantly reduced the growth of human neuroblastoma xenograft tumors by down-regulating angiogenesis, whereas PCNP knockdown markedly promoted the growth of human neuroblastoma xenograft tumors through up-regulation of angiogenesis.

Conclusions

PCNP mediates the proliferation, migration, and invasion of human neuroblastoma cells through mitogen-activated protein kinase and PI3K/AKT/mTOR signaling pathways, implying that PCNP is a therapeutic target for patients with neuroblastoma.

Afatinib

Afatinib (BIBW 2992, US: Gilotrif^TM, other countries: Giotrif©) is an irreversible blocker of the ErbB family, acting at the tyrosine kinases of these proteins. In 2013, it was approved by the FDA and the EMA for the treatment of adults with advanced, EGFR mutation-positive non-small-cell lung cancer. Further investigations for the treatment of many other tumors with afatinib, e.g., HNSCC and breast cancer, are ongoing.

Small molecule inhibitor regorafenib inhibits RET signaling in neuroblastoma cells and effectively suppresses tumor growth in vivo

Neuroblastoma (NB), the most common extracranial pediatric solid tumor, continues to cause significant cancer-related morbidity and mortality in children. Dysregulation of oncogenic receptor tyrosine kinases (RTKs) has been shown to contribute to tumorigenesis in various human cancers and targeting these RTKs has had therapeutic benefit. RET is an RTK which is commonly expressed in NB, and high expression of RET correlates with poor outcomes in patients with NB. Herein we report that RET is required for NB cell proliferation and that the small molecule inhibitor regorafenib (BAY 73-4506) blocks glial cell derived neurotrophic factor (GDNF)-induced RET signaling in NB cells and inhibits NB growth both in vitro and in vivo. We found that regorafenib significantly inhibited cell proliferation and colony formation ability of NB cells. Moreover, regorafenib suppressed tumor growth in both an orthotopic xenograft NB mouse model and a TH-MYCN transgenic NB mouse model. Finally, regorafenib markedly improved the overall survival of TH-MYCN transgenic tumor-bearing mice. In summary, our study suggests that RET is a potential therapeutic target in NB, and that using a novel RET inhibitor, like regorafenib, should be investigated as a therapeutic treatment option for children with NB.

Sustained-releasing hollow microparticles with dual-anticancer drugs elicit greater shrinkage of tumor spheroids

Polymeric particulate delivery systems are vastly explored for the delivery of chemotherapeutic agents. However, the preparation of polymeric particulate systems with the capability of providing sustained release of two or more drugs is still a challenge. Herein, poly (D, L-lactic-co-glycolic acid, 50:50) hollow microparticles co-loaded with doxorubicin and paclitaxel were developed through double-emulsion solvent evaporation technique. Hollow microparticles were formed through the addition of an osmolyte into the fabrication process. The benefits of hollow over solid microparticles were found to be higher encapsulation efficiency and a more rapid drug release rate. Further modification of the hollow microparticles was accomplished through the introduction of methyl-β-cyclodextrin. With this, a higher encapsulation efficiency of both drugs and an enhanced cumulative release were achieved. Spheroid study further demonstrated that the controlled release of the drugs from the methyl-β-cyclodextrin -loaded hollow microparticles exhibited enhanced tumor regressions of MCF-7 tumor spheroids. Such hollow dual-drug-loaded hollow microparticles with sustained releasing capabilities may have a potential for future applications in cancer therapy.