The prospect of patritumab for treating non-small cell lung cancer

HER3-targeted therapeutic antibodies and antibody-drug conjugates in non-small cell lung cancer refractory to EGFR-tyrosine kinase inhibitors

Human epidermal growth factor receptor 3 (HER3) is a unique member of the human epidermal growth factor receptor (HER/EGFR) family, since it has negligible kinase activity. Therefore, HER3 must interact with a kinase-proficient receptor to form a heterodimer, leading to the activation of signaling cascades. Overexpression of HER3 is observed in various human cancers, including non-small cell lung cancer (NSCLC), and correlates with poor clinical outcomes in patients. Studies on the underlying mechanism demonstrate that HER3-initiated signaling promotes tumor metastasis and causes treatment failure in human cancers. Upregulation of HER3 is frequently observed in EGFR-mutant NSCLC treated with EGFR-tyrosine kinase inhibitors (TKIs). Increased expression of HER3 triggers the so-called EGFR-independent mechanism via interactions with other receptors to activate "bypass signaling pathways", thereby resulting in resistance to EGFR-TKIs. To date, no HER3-targeted therapy has been approved for cancer treatment. In both preclinical and clinical studies, targeting HER3 with a blocking antibody (Ab) is the only strategy being examined. Recent evaluations of an anti-HER3 Ab-drug conjugate (ADC) show promising results in patients with EGFR-TKI-resistant NSCLC. Herein, we summarize our understanding of the unique biology of HER3 in NSCLC refractory to EGFR-TKIs, with a focus on its dimerization partners and subsequent activation of signaling pathways. We also discuss the latest development of the therapeutic Abs and ADCs targeting HER3 to abrogate EGFR-TKI resistance in NSCLC.

Role of hemoglobin alpha and hemoglobin beta in non-small-cell lung cancer based on bioinformatics analysis

The differentially expressed genes (DEGs) were identified and screened differentially in non-small-cell lung cancer (NSCLC) using information from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus databases, and the correlation of DEGs in protein interaction, function, and pathway enrichment were analyzed to search for new biomarkers and potential therapeutic targets for NSCLC. Protein-protein interaction network (PPI) analysis showed that CDK1 and GNGT1 were the most significantly upregulated hub nodes, while FPR2 was the most significantly downregulated. Gene Ontology enrichment analysis showed that upregulated DEGs were significantly enriched in protein heterodimerization activity and other functions, while downregulated DEGs were enriched in functions such as heparin-binding. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that upregulation of DEGs were significantly associated with neuroactive ligand-receptor interaction pathways, while downregulation of DEGs were significantly associated with malaria pathways. According to the analysis results, we identified hemoglobin alpha (HBA) and hemoglobin beta (HBB) as the genes of interest for further study. Through tissue level and cell level experiments, we found that the expressions of HBA and HBB in NSCLC tissues were significantly lower than those in paracancerous tissues, and downregulation of HBA and HBB could significantly affect the proliferation ability of NSCLC cells. In addition, we also found that changes in HBA and HBB may affect NSCLC cells through the p38/MAPK pathway and JNK pathway, and ultimately affect the occurrence and development of NSCLC.

Evaluation of patritumab with or without erlotinib in combination with standard cytotoxic agents against pediatric sarcoma xenograft models

BACKGROUND

Integrating molecularly targeted agents with cytotoxic drugs used in curative treatment of pediatric cancers is complex. An evaluation was undertaken with the ERBB3/Her3-specific antibody patritumab (P) either alone or with the ERBB1/epidermal growth factor receptor inhibitor erlotinib (E) in combination with standard cytotoxic agents, cisplatin, vincristine, and cyclophosphamide, in pediatric sarcoma xenograft models that express receptors and ligands targeted by these agents.

PROCEDURES

Tumor models were selected based upon ERBB3 expression and phosphorylation, and ligand (heregulin) expression. Patritumab, E, or these agents combined was evaluated without or with concomitant cytotoxic agents using procedures developed by the Pediatric Preclinical Testing Program.

RESULTS

Full doses of cytotoxic agents were tolerated when combined with P, whereas dose reductions of 25% (vincristine, cisplatin) or 50% (cyclophosphamide) were required when combined with P + E. Patritumab, E alone, or in combination did not significantly inhibit growth of any tumor model, except for Rh18 xenografts (E alone). Patritumab had no single-agent activity and marginally enhanced the activity of vincristine and cisplatin only in Ewing sarcoma ES-4. P + E did not increase the antitumor activity of vincristine or cisplatin, whereas dose-reduced cyclophosphamide was significantly less active than cyclophosphamide administered at its maximum tolerated dose when combined with P + E.

CONCLUSIONS

P had no single-agent activity, although it marginally potentiated the activity of vincristine and cisplatin in one of three models studied. However, the addition of E necessitated dose reduction of each cytotoxic agent, abrogating the enhancement observed with P alone.

Rab22a enhances CD147 recycling and is required for lung cancer cell migration and invasion

Rab22a is a member of the Ras-related small GTPase family, which plays a key role in regulating the recycling of cargo proteins entering cells through clathrin-independent endocytosis (CIE). Rab22a is overexpressed in different cancer types, including liver cancer, malignant melanoma, ovarian cancer and osteosarcoma. However, its oncogenic role remains unknown. In this study, we found that silencing of Rab22a suppressed the migration and invasion of lung cancer cells. Furthermore, Rab22a interacts with CD147, and knockdown of Rab22a blocks CD147 recycling and promotes CD147 degradation. Taken together, our findings indicate that Rab22a enhances recycling of CD147, which is required for lung cancer cell migration and invasion,and targeting CD147 recycling may be a rational strategy for lung cancer therapy.