Neuropeptide bombesin receptor activation stimulates growth of lung cancer cells through HER3 with a MAPK-dependent mechanism

Peptide G-Protein-Coupled Receptors and ErbB Receptor Tyrosine Kinases in Cancer

The ErbB RTKs (EGFR, HER2, HER3, and HER4) have been well-studied in cancer. EGFR, HER2, and HER3 stimulate cancer proliferation, principally by activating the phosphatidylinositol-3-kinase and extracellular signal-regulated kinase (ERK) pathways, resulting in increased cancer cell survival and proliferation. Cancer cells have high densities of the EGFR, HER2, and HER3 causing phosphorylation of tyrosine amino acids on protein substrates and tyrosine amino acids near the C-terminal of the RTKs. After transforming growth factor (TGF) α binds to the EGFR, homodimers or EGFR heterodimers form. HER2 forms heterodimers with the EGFR, HER3, and HER4. The EGFR, HER2, and HER3 are overexpressed in lung cancer patient tumors, and monoclonal antibodies (mAbs), such as Herceptin against HER2, are used to treat breast cancer patients. Patients with EGFR mutations are treated with tyrosine kinase inhibitors, such as gefitinib or osimertinib. Peptide GPCRs, such as NTSR1, are present in many cancers, and neurotensin (NTS) stimulates the growth of cancer cells. Lung cancer proliferation is impaired by SR48692, an NTSR1 antagonist. SR48692 is synergistic with gefitinib at inhibiting lung cancer growth. Adding NTS to lung cancer cells increases the shedding of TGFα, which activates the EGFR, or neuregulin-1, which activates HER3. The transactivation process is impaired by SRC, matrix metalloprotease, and reactive oxygen species inhibitors. While the transactivation process is complicated, it is fast and occurs within minutes after adding NTS to cancer cells. This review emphasizes the use of tyrosine kinase inhibitors and SR48692 to impair transactivation and cancer growth.

Adding of neurotensin to non-small cell lung cancer cells increases tyrosine phosphorylation of HER3

Neurotensin (NTS) receptor 1 regulates the growth non-small cell lung cancer (NSCLC) cells. NTS binds with high affinity to NTSR1, leading to increased tyrosine phosphorylation of the EGFR and HER2. Using Calu3, NCI-H358, or NCI-H441 cells, the effects of NTS on HER3 transactivation were investigated. HER3 tyrosine phosphorylation was increased by NTS or neuregulin (NRG1) addition to NSCLC cells. NCI-H358, NCI-H441, and Calu-3 cells have HER3, NTSR1 and neuregulin (NRG)1 protein. NTSR1 regulation of HER3 transactivation was impaired by SR48692 (NTSR1 antagonist) or monoclonal antibody (mAb)3481 (HER3 blocker). Immunoprecipitation experiments indicated that NTS addition to NCI-H441cells resulted in the formation of EGFR/HER3 and HER2/HER3 heterodimers. The ability of NTS to increase HER3 tyrosine phosphorylation was impaired by GM6001 (MMP inhibitor), PP2 (Src inhibitor), Tiron (superoxide scavenger), or N-acetylcysteine (antioxidant). Adding NTS to NSCLC cells increased phosphorylation of ERK, HER3, and AKT. NTS or NRG1 increased colony formation of NSCLC cells which was strongly inhibited by SR48692 and mAb3481. The results indicate that NTSR1 regulates HER3 transactivation in NSCLC cells leading to increased proliferation.

The O-glycosylating enzyme GALNT2 acts as an oncogenic driver in non-small cell lung cancer

BACKGROUND

N-Acetylgalactosaminyltransferases (GALNTs), the enzymes that initiate mucin-type O-glycosylation, are closely associated with tumor occurrence and progression. However, a comprehensive analysis of GALNTs in non-small cell lung cancer (NSCLC) is lacking.

METHODS

The expression profiles and prognostic values of the GALNT family members in NSCLC were analyzed using publicly available databases. Gain- and loss-of-function experiments were applied to assess the biological function of GALNT2 in NSCLC. High-throughput sequencing and bioinformatics approaches were employed to uncover the regulatory mechanism of GALNT2.

RESULTS

Among the family members of GALNTs, only GALNT2 was frequently overexpressed in NSCLC tissues and was positively correlated with poor prognosis. In vitro assays showed that GALNT2 knockdown repressed NSCLC cell proliferation, migration, and invasion, but induced apoptosis and cell cycle arrest. Correspondently, GALNT2 overexpression exerted the opposite effects. In vivo experiments demonstrated that knockdown of GALNT2 restrained tumor formation in nude mice. Mechanistic investigations revealed that GALNT2 modified the O-glycosylation of ITGA5 and affected the activation of the PI3K/Akt and MAPK/ERK pathways. Further studies showed that miR-30d was a negative regulator of GALNT2.

CONCLUSIONS

These findings suggest that GALNT2 is an oncogene in NSCLC and has the potential as a target for NSCLC therapy.

Neurokinin-1 receptor promotes non-small cell lung cancer progression through transactivation of EGFR

Despite the great advances in target therapy, lung cancer remains the top cause of cancer-related death worldwide. G protein-coupled receptor neurokinin-1 (NK1R) is shown to play multiple roles in various cancers; however, the pathological roles and clinical implication in lung cancer are unclarified. Here we identified NK1R as a significantly upregulated GPCR in the transcriptome and tissue array of human lung cancer samples, associated with advanced clinical stages and poor prognosis. Notably, NK1R is co-expressed with epidermal growth factor receptor (EGFR) in NSCLC patients' tissues and co-localized in the tumor cells. NK1R can crosstalk with EGFR by interacting with EGFR, transactivating EGFR phosphorylation and regulating the intracellular signaling of ERK1/2 and Akt. Activation of NK1R promotes the proliferation, colony formation, EMT, MMP2/14 expression, and migration of lung cancer cells. The inhibition of NK1R by selective antagonist aprepitant repressed cell proliferation and migration in vitro. Knockdown of NK1R significantly slowed down the tumor growth in nude mice. The sensitivity of lung cancer cells to gefitinib/osimertinib is highly increased in the presence of the selective NK1R antagonist aprepitant. Our data suggest that NK1R plays an important role in lung cancer development through EGFR signaling and the crosstalk between NK1R and EGFR may provide a potential therapeutic target for lung cancer treatment.

Ciliary GPCR-based transcriptome as a key regulator of cilia length control

The primary cilium is a plasma membrane-protruding sensory organelle that efficiently conveys signaling cascades in a highly ordered microenvironment. Its signaling is mediated, in part, by a limited set of GPCRs preferentially enriched in the cilium membrane. This includes melanin-concentrating hormone (MCH) receptor 1 (MCHR1), which plays a role in feeding and mood. In addition to its receptor composition, the length of the cilium is a characteristic parameter that is implicated in its function. We previously found that MCH can dynamically shorten cilia length via the Gi/o and Akt pathways in both MCHR1-expressing hTERT-RPE1 cells (hRPE1 cells) and rat hippocampal neurons. However, the detailed mechanisms by which MCH regulates cilia length through ciliary MCHR1 remains unclear. In this study, we aimed to determine the transcriptome changes in MCHR1-expressing hRPE1 cells in response to MCH to identify the target molecules involved in cilia length regulation via MCHR1 activation. RNA sequencing analysis of ciliated cells subjected to MCH treatment showed upregulation of 424 genes and downregulation of 112 genes compared with static control cells. Validation by quantitative real-time PCR, knocking down, and CRISPR/Cas9-mediated knockout technology identified a molecule, PDZ and LIM domain-containing protein 5 (PDLIM5). Thus, it was considered as the most significant key factor for MCHR1-mediated shortening of cilia length. Additional analyses revealed that the actin-binding protein alpha-actinin 1/4 is a crucial downstream target of the PDLIM5 signaling pathway that exerts an effect on MCHR1-induced cilia shortening. In the endogenous MCHR1-expressing hippocampus, transcriptional upregulation of PDLIM5 and actinin 1/4, following the application of MCH, was detected when the MCHR1-positive cilia were shortened. Together, our transcriptome study based on ciliary MCHR1 function uncovered a novel and important regulatory step underlying cilia length control. These results will potentially serve as a basis for understanding the mechanism underlying the development of obesity and mood disorders.

JAC1 suppresses proliferation of breast cancer through the JWA/p38/SMURF1/HER2 signaling

The overexpression of HER2 is associated with a malignant proliferation of breast cancer. In this study, we developed a non-cytotoxic JWA gene activating compound 1 (JAC1) to inhibit the proliferation of HER2-positive breast cancer cells in vitro and in vivo experimental models. JAC1 increased the ubiquitination of HER2 at the K716 site through the E3 ubiquitin ligase SMURF1 which was due to the decreased expression of NEDD4, the E3 ubiquitin ligase of SMURF1. In conclusion, JAC1 suppresses the proliferation of HER2-positive breast cancer cells through the JWA triggered HER2 ubiquitination signaling. JAC1 may serve as a potential therapeutic agent for HER2-positive breast cancer.

Recent advances in the biology of bombesin-like peptides and their receptors

PURPOSE OF REVIEW

The current review aims to update the important findings about molecular and cellular biology of mammalian bombesin-like peptides (BLPs) and their receptors.

RECENT FINDINGS

Recent identification of synaptic communication between gastrin-releasing peptide (GRP) neurons and GRP receptor (GRPR) neurons in spinal itch relay provides us novel insights into physiology of itch sensation. Neuromedin B (NMB) neurons were found to form connections with subcortical areas associated with arousal, hippocampal theta oscillation, and premotor processing and project to multiple downstream stations to regulate locomotion and hippocampal theta power. In addition to researches regarding the roles of BLPs and their receptors in central nervous system, recent findings reveal that NMB receptor is expressed on helminth-induced type 2 innate lymphoid cells and is regulated by basophils, suggesting an important function of NMB in helminth-induced immune responses. Bombesin transactivates epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), and HER3 receptors on human nonsmall-cell lung cancer (NSCLC) cells and elicits downstream signaling cascades and induces formation of both human epidermal growthfactor receptor 3 (HER3)/EGFR and HER3/HER2 heterodimers. Several high-affinity ligands for bombesin receptors were characterized, providing useful tools in investigation of biological roles of those peptides and their receptors.

SUMMARY

The most exciting findings of BLPs and their receptors in the past year come from studies in central nervous system. In addition, more researches are still underway to probe the molecular mechanisms of those peptides in peripheral tissues and characterize novel synthetic ligands with high affinity for mammalian bombesin receptors.

Pituitary adenylate cyclase-activating polypeptide/vasoactive intestinal peptide [Part 1]: biology, pharmacology, and new insights into their cellular basis of action/signaling which are providing new therapeutic targets

PURPOSE OF REVIEW

To discuss recent advances of vasoactive intestinal peptide (VIP)/pituitary adenylate cyclase-activating polypeptide (PACAP) receptors in pharmacology, cell biology, and intracellular signaling in cancer.

RECENT FINDINGS

Recent studies provide new insights into the pharmacology, cell biology of the VIP/PACAP system and show they play important roles in a number of human cancers, as well as in tumor growth/differentiation and are providing an increased understanding of their signaling cascade that is suggesting new treatment targets/approaches.

SUMMARY

Recent insights from studies of VIP/PACAP and their receptors in both central nervous system disorders and inflammatory disorders suggest possible new treatment approaches. Elucidation of the exact roles of VIP/PACAP in these disorders and development of new therapeutic approaches involving these peptides have been limited by lack of specific pharmacological tools, and exact signaling mechanisms involved, mediating their effects. Reviewed here are recent insights from the elucidation of structural basis for VIP/PACAP receptor activation as well as the signaling cascades mediating their cellular effects (using results primarily from the study of their effects in cancer) that will likely lead to novel targets and treatment approaches in these diseases.

Bombesin Receptor Family Activation and CNS/Neural Tumors: Review of Evidence Supporting Possible Role for Novel Targeted Therapy

G-protein-coupled receptors (GPCRs) are increasingly being considered as possible therapeutic targets in cancers. Activation of GPCR on tumors can have prominent growth effects, and GPCRs are frequently over-/ectopically expressed on tumors and thus can be used for targeted therapy. CNS/neural tumors are receiving increasing attention using this approach. Gliomas are the most frequent primary malignant brain/CNS tumor with glioblastoma having a 10-year survival <1%; neuroblastomas are the most common extracranial solid tumor in children with long-term survival<40%, and medulloblastomas are less common, but one subgroup has a 5-year survival <60%. Thus, there is an increased need for more effective treatments of these tumors. The Bombesin-receptor family (BnRs) is one of the GPCRs that are most frequently over/ectopically expressed by common tumors and is receiving particular attention as a possible therapeutic target in several tumors, particularly in prostate, breast, and lung cancer. We review in this paper evidence suggesting why a similar approach in some CNS/neural tumors (gliomas, neuroblastomas, medulloblastomas) should also be considered.

Study on the Drug Targets and Molecular Mechanisms of Rhizoma Curcumae in the Treatment of Nasopharyngeal Carcinoma Based on Network Pharmacology

Aim

To analyse the target of Rhizoma Curcumae in nasopharyngeal carcinoma by using network pharmacological techniques and to explore the associated molecular mechanism.

Methods

The targets of nasopharyngeal carcinoma were retrieved from the GeneCards database. At the same time, the drug therapeutic targets of Rhizoma Curcumae were obtained from the TCMSP and SymMap databases. The data were imported into the STRING database and Cytoscape 3.7.1 to construct a network of “Chinese medicine component-target-disease” interactions; then, the intersection was screened as the core Rhizoma Curcumae antinasopharyngeal cancer targets. Through GO target function and KEGG pathway enrichment analyses of the core targets, we predicted the biological processes and key signalling pathways involved in the Rhizoma Curcumae treatment of nasopharyngeal carcinoma.

Results

Twenty-five core targets of Rhizoma Curcumae in nasopharyngeal carcinoma were mined: TP53, BCL2 ICAM1 RXRA, TLR3 and TLR9, TNF, PTGS2, IL-6, CTSD, MMP2, MMP9, MMP14, TIMP2, ABCC1, ABCB1, ABCG2, and so on. The results of visual analysis showed that the Rhizoma Curcumae treatment of nasopharyngeal carcinoma mainly involves leukocyte adhesion to vascular endothelial cells, positive regulation of NF-κB import into the nucleus, regulation of the reactive oxygen species biosynthetic and metabolic process, regulation of the chemokine biosynthetic and metabolic process, various cancer-related signalling pathways, and a variety of cytokine signal transduction pathways, such as the NF-κB, TLR, IL-17, and TNF signalling pathways.

Conclusion

The core targets predicted by our research can be used as molecular markers for the treatment and prediction of nasopharyngeal carcinoma. The mechanism of Rhizoma Curcumae treatment in NPC may be related to immune regulatory pathways, the inhibition of cancer cell proliferation, metastasis, and angiogenesis, as well as the regulation of tumour microenvironment. Combined with the prediction of its associated mechanism of action, the core targets can provide targeted reference value for subsequent drug development related to Curcuma.