Epidermal Growth Factor Receptor Family Research Articles

A Preliminary Evaluation of the Prognostic Role of HER-2 and HER-3 Immunohistochemical Expression in Canine Melanomas.

Canine melanoma is a malignant and aggressive neoplasm showing clinical, histological, and molecular features similar to the human counterpart. In human medicine, epidermal growth factor receptors (EGFRs) have already been suggested as prognostic markers and potential therapeutic targets in cutaneous melanoma. The aim of this study was to evaluate the expression of HER-2 and HER-3 in canine melanomas by immunohistochemistry and correlate their expression to the clinicopathological parameters of the examined tumors. Thirty-seven canine melanoma samples were recruited. Data regarding signalment and clinical parameters were also collected. The population was composed of 18 cutaneous, 16 oral/mucosal, and three digital/foot pad melanomas. Histopathological investigations were carried out to analyze histological type, ulceration, and mitotic count. On each sample, immunohistochemistry was performed using an anti-Melan-A or anti-Melanoma antigen, i.e., anti-HER-2 and anti-HER-3 antibodies. HER-2 and HER-3 positivity were classified using already established scoring criteria and a statistical analysis was carried out. The results highlighted that HER-2 expression was observed in 48.6% of the samples and HER-3 expression in 18.9%. The highest HER 2 score (3+) was recorded in 16.2% of the samples, while the coexpression of the two receptors was detected in 13.5% of the samples. A statistically significant association (p < 0.05) was observed between the expression of HER-2 and HER-3 and the presence of ulceration in oromucosal tumors. This work confirms the expression of HER-2 and HER-3 in canine melanomas and suggests a putative association with negative prognostic parameters. Further studies are necessary to strengthen these data by increasing the samples size and combining pathological examinations with molecular biology in the investigation of EGFR family receptors.

Abstract PO5-04-02: Combination of trastuzumab competing and non-competing fully human internalizing anti-Her2 monoclonal antibodies drug conjugates increases their inhibitory effect on the growth of HER2 positive metastatic breast cancer cells

Abstract The human epidermal growth factor receptor (HER) family of receptors plays a key role in proliferation stimulator for several human cancers. In particular, HER2 is overexpressed in 15-30% of breast cancers with or without gene amplification with prognostic and predictive implications. HER2 overexpression is associated with shorter disease-free and overall survivals, resistance to hormonal agents and increased risk of brain metastasis. Trastuzumab is a humanized anti-HER2 monoclonal antibody that binds to domain IV of HER2 extracellular domain and blocks its signaling. More recently, two antibody drug conjugates using trastuzumab have been approved: Ado-Trastuzumab-Emtansine (Kadcyla) consisting of trastuzumab conjugated to the drug mertansine DM1 and fam-trastuzumab-deruxtecan-nhki (Enhertu to deliver the topoisomerase inhibitor deruxtecan. We are reporting here the development of fully human internalizing anti-HER2 antibodies with distinct epitopes on the HER2protein which compete or not with trastuzumab for binding to HER2. These monoclonal antibodies have been developed by immunizing fully human (TC-Mab mouse) mice with recombinant HER2 protein. After production of hybridoma secreting fully human immunoglobulins, the screening process included competition with trastuzumab for binding to Her2 by enzyme linked immunoassay and Octet epitope binning and affinity determination as well as internalization assay. Several internalizing antibodies able to compete or not with trastuzumab and with high affinity (Kd ranging from 10−9 M to 10−12 M) were selected. Their ability to deliver a cytotoxic payload in HER2 overexpressing breast cancer cells such as SKBR3, BT474 and AU565 was next investigated. Two groups of antibodies: one competing with trastuzumab and the other one non-competing were further characterized. Data related to these antibodies’ biochemical characteristics as well as their ability to inhibit proliferation in vitro and in vivo in mouse xenografts studies will be presented here. In conclusion, the use of fully human mice to develop monoclonal antibodies provides a powerful and attractive approach to develop fully human monoclonal antibodies against cancer targets by-passing the need for humanization and affinity maturation of antibodies. This work is supported by 5R44CA224718 SBIR grant from the National Cancer Institute. Citation Format: Ginette Serrero, Binbin Yue, Jianping Dong, Jun Hayashi. Combination of trastuzumab competing and non-competing fully human internalizing anti-Her2 monoclonal antibodies drug conjugates increases their inhibitory effect on the growth of HER2 positive metastatic breast cancer cells [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-04-02.

Targeting Cardiomyocytes with Adeno Associated Viruses to Protect Hearts from Trastuzumab-induced Cardiotoxicity

Amplification of HER2 occurs in 20% of breast cancers. HER2 (known as ErbB2 in mouse) belongs to the Epidermal Growth Factor Receptor (EGFR) family that is responsible for cell growth and survival. While HER2 does not bind ligands, it forms heterodimers with HER1 (also known as EGFR) in the presence of its ligand EGF, and HER4 following stimulation with Neuregulin. In HER2-positive breast cancer where HER2 expression is high, HER2 homodimerizes leading to excessive activation of downstream signalling and cell proliferation. Current HER2-positive breast cancer treatment involves chemotherapy with drugs called anthracyclines, such as Doxorubicin, and an antibody targeting HER2 called Trastuzumab. This combination is effective in killing HER2-positive breast tumours, however, Trastuzumab alone or in combination with anthracyclines leads to severe cardiotoxicity and heart failure in 2.6-11% of cases, making it a dose-limiting side effect. We hypothesise that cardiac toxicity can be mitigated by targeting cardiomyocytes exclusively to express a mutated (but functional) version of HER2 that is not recognised by trastuzumab. We designed 3 HER2 variants wherein the trastuzumab binding domain was mutated to disrupt binding. These HER2 mutants were transfected into HEK293T cells, and we confirmed that all 3 successfully localised to the cell membrane, and did not bind trastuzumab. We have used bioluminescence resonance energy transfer to examine the capacity of all 3 mutants to activate recruitment of Grb2 to the HER2 as part of HER1/HER2 and HER4/HER2 heterodimers; Western blotting also confirming mutants were capable of stimulating ERK and Akt phosphorylation. Future studies will evaluate the effcacy of using AAVs to instruct cardiomyocytes to express these HER2 mutants in a murine model of breast cancer. We predict that this new therapy would not only mitigate cardiac toxicity, but would also permit higher doses of trastuzumab to be used to treat breast cancer. This work is supported by Australia's National Health and Medical Research Council and the Australian Research Council. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

EGFR Inhibition by Erlotinib Rescues Desmosome Ultrastructure and Keratin Anchorage and Protects against Pemphigus Vulgaris IgG–Induced Acantholysis in Human Epidermis

Pemphigus is a severe blistering disease caused by autoantibodies primarily against the desmosomal cadherins desmoglein (DSG)1 and DSG3 which impair desmosome integrity. Especially for the acute phase, additional treatment options allowing to reduce corticosteroids would fulfill an unmet medical need. Here, we provide evidence that epidermal growth factor receptor (EGFR) inhibition by erlotinib ameliorates pemphigus vulgaris immunoglobulin G (PV-IgG) -induced acantholysis in intact human epidermis. PV-IgG caused phosphorylation of EGFR (Y845) and SRC in human epidermis. In line with that, a phosphotyrosine kinome analysis revealed a robust response associated with EGFR and SRC family kinase signaling in response to PV-IgG but not pemphigus foliaceus autoantibodies. Erlotinib inhibited PV-IgG-induced epidermal blistering and EGFR phosphorylation, loss of desmosomes as well as ultrastructural alterations of desmosome size, plaque symmetry, keratin filament insertion and restored the desmosome midline considered as hallmark of mature desmosomes. Erlotinib enhanced both single molecule DSG3 binding frequency and strength and delayed DSG3 fluorescence recovery supporting that EGFR inhibition increases DSG3 availability and cytoskeletal anchorage. Our data indicate that EGFR is a promising target for pemphigus therapy due to its link to several signaling pathways known to be involved in pemphigus pathogenesis.

DB-1310, an ADC comprised of a novel anti-HER3 antibody conjugated to a DNA topoisomerase I inhibitor, is highly effective for the treatment of HER3-positive solid tumors

BackgroundHER3 (ErbB3), a member of the human epidermal growth factor receptor family, is frequently overexpressed in various cancers. Multiple HER3-targeting antibodies and antibody–drug conjugates (ADCs) were developed for the solid tumor treatment, however none of HER3-targeting agent has been approved for tumor therapy yet. We developed DB-1310, a HER3 ADC composed of a novel humanized anti-HER3 monoclonal antibody covalently linked to a proprietary DNA topoisomerase I inhibitor payload (P1021), and evaluate the efficacy and safety of DB-1310 in preclinical models.MethodsThe binding of DB-1310 to Her3 and other HER families were measured by ELISA and SPR. The competition of binding epitope for DB-1310 and patritumab was tested by FACS. The sensitivity of breast, lung, prostate and colon cancer cell lines to DB-1310 was evaluated by in vitro cell killing assay. In vivo growth inhibition study evaluated the sensitivity of DB-1310 to Her3 + breast, lung, colon and prostate cancer xenograft models. The safety profile was also measured in cynomolgus monkey.ResultsDB-1310 binds HER3 via a novel epitope with high affinity and internalization capacity. In vitro, DB-1310 exhibited cytotoxicity in numerous HER3 + breast, lung, prostate and colon cancer cell lines. In vivo studies in HER3 + HCC1569 breast cancer, NCI-H441 lung cancer and Colo205 colon cancer xenograft models showed DB-1310 to have dose-dependent tumoricidal activity. Tumor suppression was also observed in HER3 + non-small cell lung cancer (NSCLC) and prostate cancer patient-derived xenograft (PDX) models. Moreover, DB-1310 showed stronger tumor growth-inhibitory activity than patritumab deruxtecan (HER3-DXd), which is another HER3 ADC in clinical development at the same dose. The tumor-suppressive activity of DB-1310 synergized with that of EGFR tyrosine kinase inhibitor, osimertinib, and exerted efficacy also in osimertinib-resistant PDX model. The preclinical assessment of safety in cynomolgus monkeys further revealed DB-1310 to have a good safety profile with a highest non severely toxic dose (HNSTD) of 45 mg/kg.ConclusionsThese finding demonstrated that DB-1310 exerted potent antitumor activities against HER3 + tumors in in vitro and in vivo models, and showed acceptable safety profiles in nonclinical species. Therefore, DB-1310 may be effective for the clinical treatment of HER3 + solid tumors.

Abstract CT215: Frontline vaccination with the B-cell peptide compound HER-Vaxx (IMU-131), combined with standard-of-care chemotherapy induces high levels of HER2-specific antibodies mediating ADCC and intracellular phosphorylation inhibition resulting in overall survival benefit in patients with HER2+ metastatic or advanced gastric/GEJ adenocarcinoma - Final results from Phase II/HERIZON study

Abstract Background: HER2, a member of the epidermal growth factor receptor (EGFR) family, is overexpressed in approximately 30% of gastric cancers. HER-Vaxx is a B cell peptide-based anti-HER2 vaccine (IMU-131) comprising trastuzumab’s binding site. Here, we present the results of the randomized open-label, multicenter phase 2 HERIZON trial (NCT02795988), which compared HER-Vaxx plus chemotherapy to chemotherapy alone. The study aimed to evaluate clinical (primary endpoint) and antibody (secondary endpoint) responses in patients with HER2-overexpressing gastric/gastro-esophageal junction (GC) cancer naïve to anti HER2 therapy. Methods: Patients were randomized to chemotherapy alone (n=17) or HER-Vaxx (50µg, recommended phase 2 dose) plus chemotherapy (n=19). In the HER-Vaxx group, patients received the vaccine at days 0, 14, 35, and 77, then every 63 days until disease progression. Chemotherapy consisted of oxaliplatin plus capecitabine and was started at day 0, repeated every 21 days for a maximum of 6 cycles. The clinical responses were assessed by RECIST 1.1 criteria. FACS analysis of PBMCs for immunophenotyping was carried out, as well as in vitro phosphorylation inhibition assays of HER2 and the signaling pathway kinases Akt and MAPK, and mediation of ADCC to characterize the vaccine-induced IgG antibodies. Results: A 42% survival benefit for patients treated with HER-Vaxx plus chemotherapy [median overall survival: 13.9 months (7.5, 14.3)] compared to chemotherapy alone [mOS: 8.3 months (6.0, 9.6)] was shown, which translated into an OS HR of 0.580 (80% 2-sided CI: 0.362, 0.927). A highly significant HER2-specific IgG and IgG1 antibody response at all time points, particularly after 3 or more doses of HER-Vaxx were induced (P&amp;lt;0.001). The HER-Vaxx antibody response correlated well with mediating ADCC (IgG, P=0.003; IgG1, P=0.05) and the anti-tumor effect (IgG, P=0.001; IgG1, P=0.016). Moreover, the HER-Vaxx-induced IgG antibodies exhibited binding to the gastric cancer cell line N87, with capacity to inhibit HER2 signaling pathway kinases Akt and MAPK phosphorylation. It also demonstrated decreased levels of Foxp3+ Tregs (P=0.0013). Conclusions: The previously shown safety profile of HER-Vaxx, along with the improved clinical and antibody responses in HER2-overexpressing GC patients shown here, validate the proof of concept for a first-in-class B-cell immunotherapy based on HER2 B-cell peptides. Clinical trials evaluating further treatment with HER-Vaxx in HER2+ GC are ongoing. Citation Format: Joshua Tobias, Michael Kundi, Erika Garner-Spitzer, Christoph Zielinski, Marina Maglakelidze, Zoran Andric, Zoran Petrovic, Rajnish Nagarkar, Tanuj Chawla, Leslie Mi Ok Chong, Bonnie Nixon, Sharon Yavrom, Nicholas J. Ede, Ursula Wiedermann. Frontline vaccination with the B-cell peptide compound HER-Vaxx (IMU-131), combined with standard-of-care chemotherapy induces high levels of HER2-specific antibodies mediating ADCC and intracellular phosphorylation inhibition resulting in overall survival benefit in patients with HER2+ metastatic or advanced gastric/GEJ adenocarcinoma - Final results from Phase II/HERIZON study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT215.

Immunotherapy for gastrointestinal cancer

Cancers of gastrointestinal tract make up the largest group of solid tumour diseases in Germany. The prognosis at diagnosis is often critical. Drug therapies reduce the risk of relapse after resection and can halt the progression of metastatic disease. Immunotherapies contribute increasingly to the treatment of gastrointestinal tumours. Monoclonal antibodies (mAB) against surface receptors from the epidermal growth factor receptor family (EGFR, Her2) are well established. The effect is partly based on the interruption of the oncogenic downstream signalling cascades and partly on immune effector mechanisms such as antibody-dependent cellular cytotoxicity. In clinical practice mAB directed against programmed cell death protein 1 (PD-1), its ligand (PD-L1) and cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) - so-called immune checkpoint inhibitors - play an increasing role and change the natural history of some subgroups of gastrointestinal cancers, especially those with deficient DNA mismatch repair which leads to genomic microsatellite instability.

The impact of nitric oxide on HER family post-translational modification and downstream signaling in cancer.

The human epidermal growth factor receptor (HER) family consists of four members, activated by two families of ligands. They are known for mediating cell-cell interactions in organogenesis, and their deregulation has been associated with various cancers, including breast and esophageal cancers. In particular, aberrant epidermal growth factor receptor (EGFR) and HER2 signaling drive disease progression and result in poorer patient outcomes. Nitric oxide (NO) has been proposed as an alternative activator of the HER family and may play a role in this aberrant activation due to its ability to induce s-nitrosation and phosphorylation of the EGFR. This review discusses the potential impact of NO on HER family activation and downstream signaling, along with its role in the efficacy of therapeutics targeting the family.

Abstract 5975: Characterization and pharmacokinetics of ligand traps targeting the human epidermal growth factor receptor (HER) family

Abstract Antibodies targeting HER receptors have led to successful therapeutics for multiple human malignancies. Targeting the family of HER ligands provides an alternative strategy to inhibit signaling and subsequent proliferation of cancer cells. We have engineered ligand traps that bind the growth factors activating the HER family and have characterized a series of molecules (EN2000-Fc) using Surface Plasmon Resonance (SPR). Five distinct molecules were further evaluated for improved in vivo pharmacokinetics in mice that express human neonatal Fc receptor (FcRn). Mutations in the IgG Fc known to extend the in-vivo half-life of monoclonal antibodies were incorporated into the parental EN2000-Fc to generate 3 more distinct pan HER ligand traps. In addition, an EN2000-Fc variant with a full-length hinge was engineered, which is 5-amino-acid longer N-terminally than the parental molecule. These five molecules were synthesized (&amp;gt; 300 mg of each), purified (&amp;gt;98%), and characterized for in vitro and in vivo testing. Two variants were compared by evaluating the ligand binding affinity to 11 HER ligands using SPR. Both molecules showed comparable affinity against all ligands tested, confirming reproducibility of the pan HER ligand trap engineering technology. Among the ligands, HB-EGF had the highest affinity. High binding affinities to EGF, NRG1, NRG2, betacellulin and TGFα were also measured. The serum pharmacokinetics of the different ligand traps were compared in 6- to 8-week-old female C57BL/6 mice engineered to express human FcRn. Ligand traps were administered by single tail vein injection, and serum samples collected over a 28-day interval were analyzed by ELISA. Ligand traps with engineered Fc-mutations had 3- to 4-fold greater systemic exposure (area-under-the-curve) compared to ligand traps with the parental sequence, demonstrating improved in vivo characteristics of selected engineered fusion proteins. These results provide useful information for product candidate selection and for further preclinical development of a ligand trap targeting HER family receptors. Citation Format: Daniel C. Maneval, Cindy Yang, Cynthia Trevisiol, H. Michael Shepard, Pei Jin. Characterization and pharmacokinetics of ligand traps targeting the human epidermal growth factor receptor (HER) family [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5975.

Abstract 6264: Role of Nuclear ErbB3 localization in regulating ligand-dependent ErbB2-ErbB3 heterodimer activation and downstream targets in prostate cancer

Abstract Objective: Prostate cancer (PCa)-specific nuclear expression of ErbB3, a receptor tyrosine kinase of the epidermal growth factor receptor (EGFR) family, has long been recognized. While an 80kDa nuclear variant of ErbB3 has been identified, full-length 185 kDa ErbB3 also translocates to the nucleus in PCa in a bone microenvironment and androgen status-dependent manner. Here, we studied potential mechanisms by which nuclear ErbB3 may regulate PCa progression. Methods: ErbB3 localization was investigated in vitro (human prostate cancer cell lines, LNCaP, C4-2, 22Rv1) using amiloride or heregulin-1β (ErbB3-specific ligand). ErbB3 expression and subcellular localization were analyzed using immunofluorescent microscopy and subcellular fractionation followed by immunoblot. Physiological readouts included viability, migration and reporter gene assays. Results: Here we show that ErbB3 can occupy a nuclear/perinuclear location in prostate cancer cells. The hormone sensitive PCa line LNCaP expressed higher levels of nuclear ErbB3 compared to castration resistant lines C4-2 and 22Rv1. The diuretic amiloride was previously shown to inhibit ErbB3 internalization by macropinocytosis thus we investigated whether it could also modulate ErbB3 nuclear localization in PCa cells. In LNCaP cells, amiloride dose dependently prevented ErbB3 nuclear transport, whereas in C4-2 and 22Rv1, no such effect was observed. Further analysis revealed that amiloride promoted ErbB3 expression in the membrane, where ErbB3 underwent ligand-dependent phosphorylation, formed ErbB2/ErbB3 dimers, and in turn phosphorylated the downstream targets AKT and ERK1/2 (p42/p44MAPK). On the other hand, EGFR phosphorylation and dimerization were unaffected by amiloride. Our results suggest that ErbB3 is stored in the nuclear region in an inactive form, whereas upon stress induction, including androgen deprivation, ErbB3 is translocated to the plasma membrane, where it is activated by ligand binding, and causes downstream signaling. Conclusion: We previously showed that the EGFR/ErbB2 dual inhibitor lapatinib failed to affect PCa - we now show that this may be due to modulation of nuclear and cytoplasmic ErbB3 expression. Amiloride prevented translocation (and thus expression of) ErbB3 to the nucleus and retained this RTK in the membrane, resulting in the formation of active ErbB2/ErbB3 dimers. Lapatinib was then able to inhibit and inactivate its specific target, ErbB2, thereby inducing significant apoptosis. The above indicates a novel role for nuclear ErbB3 in PCa that can be regulated by the combination of amiloride and lapatinib. Citation Format: Maitreyee K. Jathal, Maria M. Mudryj, Paramita M. Ghosh. Role of Nuclear ErbB3 localization in regulating ligand-dependent ErbB2-ErbB3 heterodimer activation and downstream targets in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6264.

Abstract 4553: DXC004A, a novel EGFR antibody-tubulysin analog conjugate demonstrated potential to broaden therapeutic opportunities for non-small cell lung cancer

Abstract EGFR is a member of the epidermal growth factor receptor (HER) family, and the over-expression of EGFR plays an important role in the growth and progression of various tumors, including non-small cell lung cancer. Monoclonal EGFR antibodies, such as cetuximab and panitumumab, have proven efficacy in various types of cancer. However, treatment with the anti-EGFR agents can be associated with toxicities of the skin, nails, hair, and eyes. Nimotuzumab (Nimo) is the first humanized monoclonal antibody targeting EGFR and has been granted approval for use in squamous cell carcinoma of head and neck (SCCHN), glioma and nasopharyngeal cancer in different countries. In contrast to cetuximab, Nimotuzumab is distinguished by achieving higher or similar complete remission rate (CRR) or overall remission rate (ORR) of the primary tumor in clinical applications but much less toxicity, resulting in a better safety profile, which has been attributed to its about 10-fold lower affinity. Paclitaxel combined with cisplatin is the first-line chemotherapy regimen for non-small cell lung cancer. A phase 2 clinical trial has confirmed that Nimotuzumab combined with concurrent chemoradiation therapy (radiation concurrent with docetaxel and cisplatin, CCRT) was well tolerated for locally advanced squamous cell lung cancer. However, the combination strategy of Nimo-CCRT has only demonstrated similar OS and PFS to those in the CCRT group. DXC004A is an ADC drug targeting EGFR, in which a Nimotuzumab derivative and a Tubulysin B analog is conjugated by a functional linker. DXC004A is in phase I clinical trial and has demonstrated clinical activity in advanced non-small cell lung cancers and good tolerability. In vitro and in vivo results had confirmed that DXC004A monotherapy had better anti-tumor activity than the combination of Nimotuzumab and Tubulysin analog in HCC827 cell lines with high EGFR expression. Meanwhile, a single injection of low-dose DXC004 (2.5 mg/kg) in HCC827 xenograft model showed very good durable anti-tumor effect. Moreover, the combination of DXC004A with Cisplatin exhibited significantly better activities than that of Nimo-CCRT combination, DXC004A or cisplatin alone, in vitro and in vivo, which might solve the predicament of poor efficacy of Nimo-CCRT combination therapy. This synergy results suggested that DXC004A plus cisplatin would possibly be a new adjuvant therapy for non-small cell lung cancer in further clinical studies. Citation Format: Xiaobo Cai, Min Cao, Huihui Guo, Qingliang Yang, Yongxiang Chen, Xiangfei Kong, Yong Du, Zhicang Ye, Zhixiang Guo, Lingli Zhang, Lu Bai, Junxiang Jia, Yunxia Zheng, Wei Zheng, Jun Zheng, Wenjun Li, Yuanyuan Huang, Zhongliang Fan, Binbin Chen, Meng Dai, Robert Y. Zhao. DXC004A, a novel EGFR antibody-tubulysin analog conjugate demonstrated potential to broaden therapeutic opportunities for non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4553.

Abstract 5083: Discovery of an asymmetric IgG-like bispecific ADC targeting EGFR/HER3

Abstract Background: The epidermal growth factor receptor (EGFR) family, consisting of EGFR, HER2, HER3, and HER4, plays a critical role in tumorigenesis and tumor progression. Inhibition of ERBBs using either monoclonal antibodies (mAb) or small-molecule tyrosine kinase inhibitors have been approved for use for the treatment of various types of cancers. Despite relative success, many patients acquire resistance to long-term benefit due to alternative compensatory signaling pathways. Accordingly, activating mutations or overexpression of HER3 has been reported in many cancers, such as breast, ovarian, lung, colorectal, melanoma, head and neck, cervical and prostate cancers. Here, we report the discovery of a humanized anti-EGFR x HER3 IgG-like bispecific antibody-drug conjugate (ADC). The ADC takes a asymmetric 1+1 form through HC-HC and HC-LC charge-based heterodimerization, which is then conjugated to a topoisomerase 1 inhibitor (TOP1i) payload via a cleavable linker. The affinity of EGFR and HER3 was optimized to improve the therapeutical window, and has shown potent anti-tumor efficacy in various tumor models with limited toxicity supporting further development in clinic. Methods: An anti-EGFR x HER3 bispecific ADC (PM1300) was generated by introducing unique mutations to the CH1-CL domains of each binding arm to avoid HC-LC mispairing. KIH mutations were also introduced to each CH3 domain to support HC/HC heterodimerization and generate an IgG-like bispecific with one arm binding to EGFR and the other to HER3. TOP1i payload was conjugated to the IgG-like bispecific by the endogenous cysteine residues at DAR 8 via a clearable linker. Results: Through affinity optimization, PM300 was found to preferentially bind to EGFR/HER3 double-positive cells rather than EGFR single-positive cells. PM1300 showed significantly increased internalization and anti-proliferation activity against EGFR/HER3 double-positive cells, with limited activity towards single positive-cells. PM1300 used an optimized linker for better payload release and serum stability. PM1300 induced a potent anti-tumor efficacy in various CDX models representing different EGFR and HER3 expressing levels and mutations. Importantly, PM1300 exhibited a good safety profile in NHP consistent with the optimal affinity for EGFR and HER3. These results demonstrate that PM1300 has a promising efficacy/safety therapeutical window in preclinical models supporting further development in the clinic. Conclusion: A bispecific ADC targeting EGFR x HER3 was discovered, named PM1300, which has an asymmetric 1+1 IgG-like structure and optimized affinity. This allows for preferential binding to EGFR/HER3 double-positive cancer cells, rather than EGFR single-positive cells. This may significantly contribute to minimizing safety risk that is common for EGFR-targeting agents. Citation Format: Liandi Chen, Shaogang Peng, Chao Wang, Xiaoniu Miao, Yao Yan, Jun Xing, Weifeng Huang, Andy Tsun, Yingda Xu, Xiaolin Liu, Yi Luo. Discovery of an asymmetric IgG-like bispecific ADC targeting EGFR/HER3 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5083.

Abstract 5152: Co-expression and prognostic significance of HER family members and EGFRvIII in patients with hepatocellular carcinoma

Abstract Hepatocellular carcinoma is one of the most common type of liver cancer. Despite advances in its treatment including the approval of several targeted agents in the past few decades, many patients do not respond or have a response of short duration to such therapeutic interventions. As a result, liver cancer is the third leading cause of cancer-related deaths worldwide. Therefore, it is essential to identify additional therapeutic targets and to develop more effective therapeutic interventions. In the past few decades, increased expression, and activation of the human epidermal growth factor receptor (HER) family members have been detected in various cancer types and of these, EGFR and HER2 are important therapeutic targets for the treatment of patients with a wide range of cancers, but currently not in liver cancer. In some studies, cross-talk between different members of the HER family has been associated with tumor progression and resistance to therapy with EGFR inhibitors but there has been no comprehensive study of the expression of all members of the HER family in patients with hepatocellular carcinoma. In this study, we examined the relative expression of all members of the HER family, type-III deletion mutant of EGFR (i.e.EGFRvIII), which is a tumor specific antigen, and two putative liver cancer cell biomarkers (i.e. CD44, EpCAM) in 43 patients with hepatocellular carcinoma by immunohistochemistry. The prognostic significance of such antigens was also investigated. Of these, the expression of EGFR, HER2, HER3, HER4 and EGFRvIII was found in tumor specimens from 35%, 58%, 0%, 19%, and 26% of the cases, respectively. Interestingly, at a cut off value of &amp;gt;5% of tumor cells with staining, 23%, 14% and 9% of the patients had co-expression of EGFR with HER2, EGFRvIII, and HER2/EGFRvIII. In addition, 40% and 33% of the cases were CD44 and EpCAM positive. Of these, the expression of EGFRvIII positivity at &amp;gt;5% ( HR=3.35, p=0.002) and 20% (HR=7.22, p=0.003) of tumour cells and membranous CD44 ( HR=2.12, p=0.04) were associated with a poorer survival in patients with hepatocellular carcinoma. In contrast, the expression of cytoplasmic CD44 was associated with a better overall survival (HR=0.30, p=0.02). These were found to be independent prognostic markers in multivariate analysis. Interestingly, the co-expression of EGFR with EGFRvIII was associated with a poorer overall survival (59.5 vs 21.0 months, p=0.004). Taken together, our results suggest that the expression of EGFRvIII occurs in patients with hepatocellular carcinoma and highlight its importance as biomarker for tumor progression and as a potential target for therapeutic intervention with drugs targeting EGFRvIII and other members of HER family. Citation Format: Ozlem Sherif, Said Khelwatty, Izhar Bagwan, Alan Seddon, Angus Dalgleish, Satvinder Mudan, Helmout Modjtahedi. Co-expression and prognostic significance of HER family members and EGFRvIII in patients with hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5152.

Abstract 7217: Orthogonal targeting of NAD metabolism and ErbB2/ErbB3 signaling in pancreatic adenocarcinoma

Abstract Background: Pancreatic ductal adenocarcinoma (PDAC) is now the third leading cause for cancer related deaths in the US with a five-year survival of ~10% that has improved little over the past 20 years. Thus, there is a critical need to fully understand mechanisms of PDAC tumorigenesis in order to develop novel and effective therapies. Nicotinamide Adenine Dinucleotide (NAD), a critical co-factor and energy source required for cellular processes such as DNA repair and epigenetic regulation is frequently upregulated in PDAC. We recently reported a novel oncogenic axis connecting the NAD-dependent epigenetic regulator and oncogene C-terminal Binding Protein (CtBP) with the EGFR family growth factor receptors ErbB2/ErbB3 (ErbB2/3) in PDAC cells and tumors. Indeed, previous reports have shown ~30% of human PDAC tumors overexpress ErbB3, and our work has shown that PDAC tumor cell growth relies on maintenance of ErbB3 expression. Moreover, we show that the majority of PDAC cells with high levels of ErbB3 expression are uniquely sensitive to the ErbB2-targeted tyrosine kinase inhibitor lapatinib. In addition, we have recently shown that co-targeting NAD and CtBP with small molecule inhibitors is an effective and synergistic therapeutic strategy in PDAC model systems. Methods and Results: In the current study, we demonstrate NAD-dependent regulation of ErbB2/3 signaling in PDAC cells in vitro. Upon depletion of NAD using the NAD salvage pathway inhibitor GMX1778 in human PDAC cells, we observed a striking coordinate decrease in the levels of both ErbB2 and ErbB3. Furthermore, stable knockdown of the limiting enzyme of the complementing Preiss-Handler NAD synthetic pathway, Nicotinamide Adenine Phosphoribosyl Transferase, also resulted in robust downregulation of ErbB2/3 protein levels, suggesting a direct linkage in PDAC cells between the status of NAD metabolism and synthesis and activity of the key growth factor receptors ErbB2/3. Conclusions: Our findings highlight the novel connection between NAD and ErbB2/3 in PDAC. Furthermore, our data suggests combining chemical or biologic inhibitors of ErbB2/3 with an inhibitor of NAD synthesis may result in highly synergistic cytotoxic effects in PDAC cells and PDAC preclinical models. Such data could support the future development of a human PDAC clinical trial repurposing agents targeting NAD synthesis and ErbB2/3 that are already FDA-approved or currently in clinical testing. Citation Format: Kranthi Kumar Chougoni, Nari Kim, Martin M. Dcona, Diana T. Dcona, Gautam K. Malhotra, Steven R. Grossman. Orthogonal targeting of NAD metabolism and ErbB2/ErbB3 signaling in pancreatic adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7217.

Potential protein kinase inhibitors that target G-quadruplex DNA structures in the human telomeric regions.

Telomeric regions contain Guanine-rich sequences arranged in a planar manner and connected by Hoogsteen hydrogen bonds that can fold into G-quadruplex (G4) DNA structures, and can be stabilized by monovalent metal cations. The presence of G4 DNA holds significance in cancer-related processes, especially due to their regulatory potential at transcriptional and translational levels of oncogene and tumor suppressor genes. The objective of this current research is to explore the evolving realm of FDA-approved protein kinase inhibitors, with a specific emphasis on their capacity to stabilize the G4 DNA structures formed at the human telomeric regions. This involves investigating the possibility of repurposing FDA-approved protein kinase inhibitors as a novel approach for targeting multiple cancer types. In this context, we have selected 16 telomeric G4 DNA structures as targets and 71 FDA-approved small-molecule protein kinase inhibitors as ligands. To investigate their binding affinities, molecular docking of human telomeric G4 DNA with nuclear protein kinase inhibitors and their corresponding co-crystalized ligands were performed. We found that Ponatinib and Lapatinib interact with all the selected G4 targets, the binding free energy calculations, and molecular dynamic simulations confirm their binding efficacy and stability. Thus, it is hypothesized that Ponatinib and Lapatinib may stabilize human telomeric G4 DNA in addition to their ability to inhibit BCR-ABL and the other members of the EGFR family. As a result, we also hypothesize that the stabilization of G4 DNA might represent an additional underlying mechanism contributing to their efficacy in exerting anti-cancer effects.

New oxadiazole and pyrazoline derivatives as anti-proliferative agents targeting EGFR-TK: design, synthesis, biological evaluation and molecular docking study

Two new series of oxadiazole and pyrazoline derivatives were designed and synthesized as promising EGFR-TK inhibitors. The in vitro antiproliferative activity was studied against three human cancer cell lines; HCT116, HepG-2 and MCF7 using MTT assay. Compound 10c showed the most potent anticancer activity against all cancer cell lines, with IC50 range of 1.82 to 5.55 μM, while proving safe towards normal cells WI-38 (IC50 = 41.17 μM) compared to the reference drug doxorubicin (IC50 = 6.72 μM). The most active candidates 5a, 9b, 10a, 10b and 10c were further assessed for their EGFR-TK inhibition. The best of which, compounds 5a and 10b showed IC50 of 0.09 and 0.16 μM respectively compared to gefitinib (IC50 = 0.04 μM). Further investigation against other EGFR family members, showed that 5a displayed good activities against HER3 and HER4 with IC50 values 0.18 and 0.37 µM, respectively compared to gefitinib (IC50 = 0.35 and 0.58 µM, respectively). Furthermore, 5a was evaluated for cell cycle distribution and apoptotic induction on HepG-2 cells. It induced mitochondrial apoptotic pathway and increased accumulation of ROS. Molecular docking study came in agreement with the biological results. Compounds 5a and 10b showed promising drug-likeness with good physicochemical properties.

Unraveling Proto-Oncogene (ErbB2) Expression in Patients With Carcinoma Head of Pancreas and Chronic Pancreatitis Patients: A Case-Control Study.

Background The pre-malignant tendency of the normal, non-affected portion of the pancreas is not as well explored as the multicentricity documented in pancreatic cancer cases. In order to ascertain the expression of inflammatory markers and Erythroblastic Oncogene B (ErbB2) in the non-affected pancreas in patients with pancreatic cancer, a case-control study was carried out. Materials and methods In patients who underwent pancreatoduodenectomy for pancreatic cancer (PC), pro-inflammatory genes and a tumor marker, erythroblastic oncogene 2 (ErbB2) in the epidermal growth factor receptor family were analyzed in the pancreatic tissue at the cut surface of the normal pancreas using qRT-PCR. Twenty patients diagnosed with Chronic pancreatitis (CP) after Frey's surgical procedure were selected, and their pancreatic tissues were analyzed as controls. The HPLC-purified primers were designed using National Center for Biotechnology Information (NCBI) software. The primer's specificity was verified for gene expression analysis using the Basic Local Alignment Search Tool (BLAST). The genes under study were normalized using β-actin as the housekeeping gene, and the 2-ddct method was used to compute the fold change compared to the control sample. Results Patients with margin-positive were not included. Pro-inflammatory genes (TNF-α, NF-kβ,andCOX-2) had significantly lower foldchange in PC patients compared to the CP group. The CP control group had higher levels ofIL-6gene expression than the PC group. Patients with pancreatic cancer had a considerably higher expression of theErbB2gene than patients with CP. Conclusion The upregulatedErbB2gene in the unaffected pancreatic tissue of pancreatic cancer patients, when compared to controls, indicates that the remaining pancreas may have the capacity to cause cancer. Proto-oncogene may play a role in the pathophysiologic process in patients with pancreatic cancer.

Molecular docking and molecular dynamics approach to identify EGFR and HER2 receptors inhibitory effect of compounds in Zanthoxylum simulans Hance

AbstractEpidermal growth factor receptor (EGFR) and human epithelium receptor‐2 (HER2) are members of the epidermal growth factor receptor (EGFR/ErbB) family implicated in the development of many types of carcinoma. Zanthoxylum simulans Hance has the effect of inhibiting growth and causing the death of many types of cancer cells. In this study, the molecular docking method and molecular dynamics simulations were used to evaluate the inhibition abilities of EGFR and HER2 receptors of 120 compounds in Zanthoxylum simulans Hance. The results showed two compounds that inhibit both EGFR and HER2 targets including simulanoquinoline and 6‐acetonyldihydroavicine. Therefore, in vivo and in vitro studies of these potential compounds should be carried out to become anti‐cancer drugs in the future.

Romidepsin and Afatinib Abrogate Jak–Signal Transducer and Activator of Transcription Signaling and Elicit Synergistic Antitumor Effects in Cutaneous T-Cell Lymphoma

Cutaneous T-cell lymphomas (CTCL) are mature lymphoid neoplasias resulting from the malignant transformation of skin-resident T cells. A distinctive clinical feature of CTCL is their sensitivity to treatment with histone deacetylase (HDAC) inhibitors. However, responses to HDAC inhibitor therapy are universally transient and non-curative, highlighting the need for effective and durable drug combinations. Here we demonstrate that the combination of romidepsin, a selective class I HDAC inhibitor, with afatinib, an epidermal growth factor receptor (EGFR) family inhibitor, induces strongly synergistic antitumor effects in CTCL models in vitro and in vivo via abrogation of JAK-STAT signalling. These results support a previously unrecognized potential role for HDAC inhibitor plus afatinib combination in the treatment of CTCL.

Pan-EGFR Inhibitor Dacomitinib Resensitizes Paclitaxel and Induces Apoptosis via Elevating Intracellular ROS Levels in Ovarian Cancer SKOV3-TR Cells.

Paclitaxel is still used as a standard first-line treatment for ovarian cancer. Although paclitaxel is effective for many types of cancer, the emergence of chemoresistant cells represents a major challenge in chemotherapy. Our study aimed to analyze the cellular mechanism of dacomitinib, a pan-epidermal growth factor receptor (EGFR) inhibitor, which resensitized paclitaxel and induced cell cytotoxicity in paclitaxel-resistant ovarian cancer SKOV3-TR cells. We investigated the significant reduction in cell viability cotreated with dacomitinib and paclitaxel by WST-1 assay and flow cytometry analysis. Dacomitinib inhibited EGFR family proteins, including EGFR and HER2, as well as its downstream signaling proteins, including AKT, STAT3, ERK, and p38. In addition, dacomitinib inhibited the phosphorylation of Bad, and combination treatment with paclitaxel effectively suppressed the expression of Mcl-1. A 2'-7'-dichlorodihydrofluorescein diacetate (DCFH-DA) assay revealed a substantial elevation in cellular reactive oxygen species (ROS) levels in SKOV3-TR cells cotreated with dacomitinib and paclitaxel, which subsequently mediated cell cytotoxicity. Additionally, we confirmed that dacomitinib inhibits chemoresistance in paclitaxel-resistant ovarian cancer HeyA8-MDR cells. Collectively, our research indicated that dacomitinib effectively resensitized paclitaxel in SKOV3-TR cells by inhibiting EGFR signaling and elevating intracellular ROS levels.