Announcer
Welcome to ReachMD. This medical industry feature titled, “HER2 (ERBB2) Mutations in NSCLC: Mechanism of Disease”, is sponsored by Daiichi Sankyo and AstraZeneca.
Host
HER2 (ERBB2) Mutations in Non-Small Cell Lung Cancer: Mechanism of Disease.
The HER Receptor Family and HER2 (ERBB2) Mutations in Non-Small Cell Lung Cancer.
HER2, or human epidermal growth factor receptor 2, is 1 of 4 receptor tyrosine kinases in the HER family. These receptors can be activated to transmit intracellular signals through homodimerization or heterodimerization, resulting in cell growth, differentiation, movement, and survival.
During activation, the tyrosine kinase domain of EGFR, HER2, and HER4 becomes phosphorylated, but this activity is impaired in HER3. And while EGFR, HER3, and HER4 can initiate intracellular signaling by binding to a ligand, HER2 cannot.
Although HER2 has no known ligand, it is the preferred binding partner of the other HER receptors, and it provides the strongest activation across all possible heterodimers.
Alterations of EGFR and HER2 play a critical role in the pathogenesis of several cancers.
In lung adenocarcinoma, three subsets of HER2 alterations—HER2 gene amplification, HER2 receptor overexpression, and HER2 genetic mutations—have been investigated with anti-HER2 agents in clinical trials but with disappointing results.
Activating HER2 mutations, often called ERBB2 mutations, account for 2-4% of all lung adenocarcinomas, but they also play a role in other forms of cancer, including bladder, stomach, and cervical cancer.
HER2 is a membrane receptor. When mutated, it may lead to the development of non-small cell lung cancer and other cancers.
The Effect of HER2 (ERBB2) Mutations on Intracellular Signaling.
In lung adenocarcinoma, HER2 gene mutations, also called ERBB2 mutations, change the shape of the HER2 receptor and trigger hyperactive signaling.
Mutations rarely occur in the extracellular and transmembrane domains of HER2. But 80 to 90 percent of HER2 mutations in non-small cell lung cancer are in the kinase domain and are intrinsically resistant to many currently approved targeted therapies due to changes in the shape of the receptor.
Normally, HER2 signals through the PI3K and MAPK pathways, which stimulate cell growth, differentiation, movement, and survival. However, mutations in HER2 make the receptor hyperactive and increase its rate of heterodimerization, even in the absence of a true ligand. This promotes uncontrolled cell growth and tumorigenesis. Mutations in HER2 can also affect the rate of receptor internalization.
HER2 gene mutations in non-small cell lung cancer may trigger hyperactive signaling that promotes uncontrolled cell growth and tumorigenesis.
The Effect of HER2 (ERBB2) Mutations on Receptor Internalization.
Receptor internalization is a process that transports large molecules such as proteins and transmembrane receptors into a cell. It is controlled by the action of receptors binding to their ligands. During internalization, the plasma membrane encloses a portion of the external environment to form an endosome.
Once inside an endosome, receptors and their ligands may either be recycled and return to the cell surface or be degraded inside a lysosome, allowing the release of nutrients back into the cell.
Therapeutic agents such as antibody-drug conjugates, which are investigational in non-small cell lung cancer, may rely on this natural mechanism of receptor internalization to release their cytotoxic payload inside the cell.
Like other receptors, HER2 receptors are internalized. However, the rate of HER2 internalization is faster when certain mutations exist in the extracellular or kinase domains.
HER2 mutations found in non-small cell lung cancer may increase the rate of HER2 receptor internalization. Antibody-drug conjugates, which are investigational in non-small cell lung cancer, may rely upon receptor internalization.
Announcer
This program was sponsored by Daiichi Sankyo and AstraZeneca. If you missed any part of this discussion, visit reachmd.com/industryfeature. This is ReachMD. Be part of the knowledge.
Intended of US Audiences Only
©2022 Daiichi Sankyo, Inc. and AstraZeneca. PP-US-8201a-1330 05/22
References
Arcila ME, Chaft JE, Nafa K, et al. Prevalence, clinicopathologic associations, and molecular spectrum of ERBB2 (HER2) tyrosine kinase mutations in lung adenocarcinomas. Clin Cancer Res. 2012;18(18):4910-4918.
Baraibar I, Mezquita L, Gil-Bazo I, Planchard D. Novel drugs targeting EGFR and HER2 exon 20 mutations in metastatic NSCLC.
Crit Rev Oncol Hematol. 2020;148:102906. doi:10.1016/j.critrevonc.2020.102906
Barok M, Joensuu H, Isola J. Trastuzumab emtansine: mechanisms of action and drug resistance. Breast Cancer Res. 2014;16(2):209.
García-Alonso S, Ocaña A, Pandiella A. Resistance to antibody-drug conjugates. Cancer Res. 2018 May 1;78(9):2159-2165.
Garrido-Castro AC, Felip E. HER2 driven non-small cell lung cancer (NSCLC): potential therapeutic approaches. Transl Lung Cancer Res. 2013;2(2):122-127.
Gutierrez C, Schiff R. HER2: biology, detection, and clinical implications. Arch Pathol Lab Med. 2011;135(1):55-62.
Jebbink M, de Langen AJ, Boelens MC, Monkhorst K, Smit EF. The force of HER2 - A druggable target in NSCLC? Cancer Treat Rev. 2020;86:101996. doi:10.1016/j/ctrv/2020/101996
Kim EK, Kim KA, Lee CY, Shim HS. The frequency and clinical impact of HER2 alterations in lung adenocarcinoma. PLoS One. 2017;12(2):e0171280. doi:10.1371/journal.pone.0171280
Leyton JV. Improving receptor-mediated intracellular access and accumulation of antibody therapeutics—the tale of HER2.
Antibodies (Basel). 2020;9(3):32. doi:10.3390/antib9030032
Li BT, Michelini F, Misale S, et al. HER2-mediated internalization of cytotoxic agents in ERBB2 amplified or mutant lung cancers.
Cancer Discov. 2020;10(5):674-687.
Li C, Sun Y, Fang R, et al. Lung adenocarcinomas with HER2-activating mutations are associated with distinct clinical features and
HER2/EGFR copy number gains. J Thorac Oncol. 2012;7(1):85-89.
Meric-Bernstam F, Johnson AM, Dumbrava EEI, et al. Advances in HER2-targeted therapy: novel agents and opportunities beyond breast and gastric cancer. Clin Cancer Res. 2019;25(7):2033-2041.
Mescher AL. The cytoplasm. In: Mescher AL, ed. Junqueira's Basic Histology Text and Atlas. 16th ed. McGraw Hill; 2021.
Mishra R, Hanker AB, Garrett JT. Genomic alterations of ERBB receptors in cancer: clinical implications. Oncotarget. 2017; 30;8(69):114371-114392.
Oh DY, Bang YJ. HER2-targeted therapies—a role beyond breast cancer. Nat Rev Clin Oncol. 2020;17(1):33-48.
Pegram MD, Miles D, Tsui CK, Zong Y. HER2-overexpressing/amplified breast cancer as a testing ground for antibody-drug conjugate drug development in solid tumors. Clin Cancer Res. 2020;26(4):775-786.
Pillai RN, Behera M, Berry LD, et al. HER2 mutations in lung adenocarcinomas: a report from the Lung Cancer Mutation Consortium.
Ricciardi GR, Russo A, Franchina T, et al. NSCLC and HER2: between lights and shadows. J Thorac Oncol. 2014;9(12):1750-1762.
Rinnerthaler G, Gampenrieder SP, Greil R. HER2 directed antibody-drug-conjugates beyond T-DM1 in breast cancer. Int J Mol Sci. 2019;20(5):1115.
Tsurutani J, Iwata H, Krop I, et al. Targeting HER2 with trastuzumab deruxtecan: a dose-expansion, phase I study in multiple advanced solid tumors. Cancer Discov. 2020;10(5):688-701.
Xu Y, Xia J, Liu S, et al. Endocytosis and membrane receptor internalization: implication of F-BAR protein Carom. Front Biosci (Landmark Ed). 2017;22:1439-1457.
Zhang X, Gureasko J, Shen K, Cole PA, Kuriyan J. An allosteric mechanism for activation of the kinase domain of epidermal growth factor receptor. Cell. 2006;125(6):1137-1149.
Zhao J, Xia Yang. Targeting HER2 alterations in non–small-cell lung cancer: a comprehensive review. JCO Precision Oncology.
2020;4:411-425.