Chinese physician perception on the treatment of chemotherapy-induced anemia: online cross-section survey study.

BACKGROUND: The management of chemotherapy induced anemia (CIA) remains challenging. The potential risk and benefits in providing patient-centered care need to be balanced; the disease is multifactorial; and the major treatments including red blood cell (RBC) transfusions, erythropoiesis-stimulating agents (ESAs) and intravenous injection (i.v.)iron supplementation have a unique set of strengths and limitations. Also, most previous survey based on the patient data could not reveal the process of evaluation and decision-making for CIA treatment from a physician's perspective. As the comparison of China Society of Clinical Oncology (CSCO), National Comprehensive Cancer Network (NCCN) and European Society of Medical Oncology (ESMO) guidelines, the standard of CIA treatment in China will vary from United States and Europe, for example, the initial hemoglobin (Hb) for RBC transfusions. In order to understand the diagnosis, treatment, and unmet medical needs of CIA patients, the China Medical Education Association (CMEA), in conjunction with Cancer Hope Medium, initiated the first national survey of Chinese physicians regarding the diagnosis and treatment of CIA. METHODS: The CMEA sent an online, 12-item questionnaire (via wjx.cn) to physicians across China from September 1, 2022 to October 22, 2022. Two hundred and sixty-five samples were calculated usingsurveyplanet.com. The questionnaire evaluated the impact of anemia on chemotherapy interruption, initial treatment, the target Hb level of CIA in, and the current status of ESAs prescription in clinical practice. Respondents were asked to score their reasons for not using ESAs (including safety issues, drug access in practice or adherence) and the risk options of the current treatment including ESAs, RBC transfusion, and i.v.iron. RESULTS: A total of 331 questionnaires among 5,000 web visits were gathered, covering 247 hospitals in 29 provinces across China, of which 130 (53%) were tier IIIA hospitals, 50 (20%) were tier III B hospitals, 59 (24%) were tier IIA hospitals, and 8 (3%) were tier II B hospitals. The frequency of chemotherapy dose delay/reduction due to anemia was 24% [standard deviation (SD) 49%]. Most responding physicians rated an initial Hb level for ESAs treatment to be 80 g/L, with a favorable Hb level for chemotherapy being 100 g/L (60%), which would not limit treatment availability. The majority (67.6%, n=221) of physicians who responded indicated that they had used ESAs for anemia correction, while the others (32.4%, n=106) reported never using them. CONCLUSIONS: This is the first study in conducting a large-scale survey on the diagnosis and treatment of CIA in China from a physicians' perspective. We found that in China, nearly one-quarter of patients undergoing chemotherapy with concurrent anemia may experience interruption of chemotherapy and that the initiation of anemia treatment is not adequately timed. In treating CIA, most physicians prioritize the completion of chemotherapy via Hb level over treating the symptoms of anemia.

Clinical characteristics and treatment outcomes of HER2 mutation and HER2 fusion in 22 patients with advanced breast cancer.

BACKGROUND: The clinical characteristics and efficacy of human epidermal growth factor receptor-2 (HER-2)-directed agents against HER2 mutations and HER2 fusions in breast cancer are obscure due to their low frequency. METHODS: We conducted a retrospective study in patients with advanced breast cancer harboring HER2 mutations and/or HER2 fusions between January 1, 2017 and January 1, 2021. RESULTS: Among a total of 22 patients, 17 HER2 mutations were detected, including L755S, S310F, R100=, V777L, R897W, T862A, 440-17C > G, H878Y, V842I, 73 + 9G > C, T278fs, E1069K, L755P, 226-11C > T, 574 + 12C>T, L114V and P128L. The majority of patients had ductal carcinoma, which mostly coexisted with HER2 amplification/overexpression. The median progression-free survival (PFS) of the 22 patients was 6.9 months (95% CI: 4.7, 9.1) in the first-line setting. The median PFS of patients who received first-line trastuzumab-based regimens was significantly longer than that of patients who received a first-line tyrosine kinase inhibitor (TKI) (10.8 months [95% CI: 2.9, 18.7] vs. 1.9 months [95% CI: 0.8, 3.0], p < 0.005). A total of 14 patients were treated with anti-HER2 antibody-drug conjugate (ADC), among whom the median treatment line of first-time of administration of anti-HER2 ADC was 4.5 (range, 1-10). Anti-HER2 ADC reached an objective response rate (ORR) of 42.9%, a disease control rate (DCR) of 85.7% and a median PFS of 7.3 months (95% CI: 4.4-10.1) from the first-time of administration. CONCLUSION: Our data demonstrated the clinical benefit of anti-HER2 treatment in Chinese breast cancer patients harboring HER2 mutation and/or HER2 fusion. The value of immunotherapy and treatment selection among individual HER2 variants needs further study.

Phase I study of A166, an antibody‒drug conjugate in advanced HER2-expressing solid tumours.

In this phase I study, the safety, pharmacokinetics, and antitumour activity of the HER2-targeted antibody-drug conjugate A166 were evaluated in patients with HER2-expressing advanced solid tumours. Patients with advanced solid tumours refractory to standard therapies received A166 at doses of 0.1, 0.3, 0.6, 1.2, 2.4, 3.6, 4.8 or 6.0 mg/kg Q3W in a standard "3 + 3" design. Dose cohorts were expanded at 4.8 and 6.0 mg/kg Q3W. Primary endpoints were assessment of the safety and tolerability of A166 and identification of the maximum tolerated dose or recommended phase II dose. In total, 81 patients were enroled and received A166 (n = 1 for 0.1 mg/kg; n = 3 for each of 0.3, 0.6, 1.2, 2.4 and 3.6 mg/kg doses; n = 27 for 4.8 mg/kg; n = 38 for 6.0 mg/kg). No dose-limiting toxicity or drug-related deaths occurred. The most common treatment-related adverse events at grade 3 or higher were corneal epitheliopathy (30.9%), blurred vision (18.5%), dry eyes (7.4%), and peripheral sensory neuropathy (6.2%). The Cmax and area under the curve of Duo-5, its free payload, were approximately 0.1% and 0.2% of those of the ADC, respectively. For all assessable HER2-positive breast cancer patients enroled in the 4.8 mg/kg and 6.0 mg/kg cohorts, the corresponding ORRs were 73.9% (17/23) and 68.6% (24/35), respectively, and the median PFS was 12.3 and 9.4 months, respectively. A166 has a recommended phase II dose of 4.8 mg/kg Q3W, manageable toxicity, good stability in the circulation and promising antitumour activities in HER2-positive breast cancer patients.

Enhanced CHOLESTEROL biosynthesis promotes breast cancer metastasis via modulating CCDC25 expression and neutrophil extracellular traps formation.

Neutrophil extracellular traps (NETs) has been demonstrated to regulate the metastasis of breast cancer. In this study, we showed that de novo cholesterol biosynthesis induced by ASPP2 depletion in mouse breast cancer cell 4T1 and human breast cancer cell MDA-MB-231 promoted NETs formation in vitro, as well as in lung metastases in mice intravenously injected with ASPP2-deficient 4T1 cells. Simvastatin and berberine (BBR), cholesterol synthesis inhibitors, efficiently blocked ASPP2-depletion induced NETs formation. Cholesterol biosynthesis greatly enhanced Coiled-coil domain containing protein 25 (CCDC25) expression on cancer cells as well as in lung metastases. CCDC25 expression was co-localized with caveolin-1, a lipid raft molecule, and was damped by inhibitor of lipid rafts formation. Our data suggest that cholesterol biosynthesis promotes CCDC25 expression in a lipid raft-dependent manner. Clinically, the expression of CCDC25 was positively correlated with the expression of 3-hydroxy-3-methylglutaryl-CoAreductase (HMRCG), and citrullinated histone H3 (H3cit), in tissues from breast cancer patients. High expression of CCDC25 and HMGCR was related with worse prognosis in breast cancer patients. In conclusion, our study explores a novel mechanism for de novo cholesterol biosynthesis in the regulation of CCDC25 expression, NETs formation and breast cancer metastasis. Targeting cholesterol biosynthesis may be promising therapeutic strategies to treat breast cancer metastasis.

Dalpiciclib Combined With Pyrotinib and Letrozole in Women With HER2-Positive, Hormone Receptor-Positive Metastatic Breast Cancer (LORDSHIPS): A Phase Ib Study.

Purpose: The LORDSHIPS study aimed to explore the safety and efficacy of a novel fully oral triplet combination of dalpiciclib (a potent cyclin-dependent kinase 4/6 inhibitor), pyrotinib (a HER2 tyrosine kinase inhibitor) and endocrine therapy letrozole in patients with HER2-positive, hormone receptor (HR)-positive metastatic breast cancer (MBC) in the front-line setting. Patients and Methods: Postmenopausal women with HER2-positive, HR-positive MBC were recruited in the dose-finding phase Ib trial. A standard 3 + 3 design was used to determine safety, tolerability, and recommended phase II dose (RP2D) for the combination. Results: A total of 15 patients were enrolled to three dose combination cohorts (letrozole/pyrotinib/dalpiciclib, level/I: 2.5/400/125 mg, n=5; level/L1: 2.5/400/100 mg, n=6; level/L2: 2.5/320/125 mg, n=4). Three patients experienced dose-limiting toxicities (level/I, n=2; level/L1, n=1) and level/L2 was identified as RP2D. The most frequent grade 3-4 adverse events were neutropenia (46.7%), leukopenia (40.0%), oral mucositis (26.7%) and diarrhea (20.0%). The confirmed objective response rate (ORR) was 66.7% (95% CI: 38.4% to 88.2%). The confirmed ORR of study treatment as first line (1L) and second line (2L) HER2-targeted therapy was 85.7% (6/7) and 50.0% (4/8), respectively. Median progression-free survival (PFS) was 11.3 months (95% CI: 5.3 months to not reached). PFS in 1L setting was not reached yet, while PFS in 2L setting was 10.9 months (95% CI: 1.8 to 13.7 months). Conclusions: The fully oral combination of dalpiciclib, pyrotinib and letrozole is a promising chemotherapy-sparing treatment option for HER2-positive, HR-positive MBC patients. The planned dose-expansion phase II study is ongoing. Clinical Trial Registration: ClinicalTrials.gov, identifier NCT03772353.

Rh-endostatin combined with chemotherapy in patients with advanced or recurrent mucosal melanoma: retrospective analysis of real-world data.

BACKGROUND: Mucosal melanoma is rare and has distinct clinical and genetic features. Even with advances in targeted and immune therapies, the survival of patients with advanced or recurrent mucosal melanomas remains poor. The standard treatment remains controversial and we conducted this real-world study aimed to explore continuous intravenous recombinant human endostatin (Rh-endostatin) infusion plus chemotherapy in this population in the first-line setting. METHODS: Overall, 43 patients with advanced or recurrent mucosal melanoma treated at Fudan University Shanghai Cancer Center between April 2017 and August 2020 were retrospectively included. Patients received dacarbazine plus cisplatin or temozolomide plus cisplatin per the investigators' preference. Rh-endostatin (105 mg/m2) was administered with continuous infusion for 168 h (Civ 168 h). RESULTS: Of the 43 patients, 72.1% had metastatic disease, and the most common primary site was the gastrointestinal tract (51.2%). The most commonly observed mutations were NRAS (23.1%), BRAF (7.7%) and CKIT mutations (5.1%). An objective response was observed in 12 (30.0%) of the 40 evaluable patients, and disease control was achieved in 31 (77.5%) patients. With a median follow-up of 17.6 months, the median progression-free survival (PFS) and overall survival (OS) were 4.9 and 15.3 months, respectively. Additionally, high lymphocyte-to-monocyte ratio (LMR) (p = 0.023, HR 0.29, 95% CI: 0.10-0.84) and BRAF/KIT/RAS mutation (p = 0.028, HR 0.24, 95% CI: 0.07-0.86) were independently correlated with prolonged OS. Toxicity was manageable overall. CONCLUSION: Continuous Rh-endostatin infusion plus chemotherapy was effective and safe for the treatment of advanced or recurrent mucosal melanoma. High LMR was correlated with favorable PFS and OS in this patient population.

Phase II study of chidamide in combination with cisplatin in patients with metastatic triple-negative breast cancer.

BACKGROUND: Platinum-based regimens are the mainstay treatments for advanced triple-negative breast cancer (TNBC). Preclinical studies have shown that the histone deacetylase (HDAC) inhibitor chidamide induced antitumor effects in TNBC, and chidamide plus chemotherapy was shown to be tolerable in several malignancies. This study sought to investigate the efficacy and safety of a combination treatment of chidamide and cisplatin in metastatic TNBC patients. METHODS: In this phase II, single-arm study, women with metastatic TNBC were administered chidamide (20 mg twice weekly for 2 weeks on a 21-day cycle) and cisplatin (75 mg/m2 on a 21-day cycle). The primary endpoint was the objective response rate (ORR) by RECIST 1.1. The severity of adverse events was measured by the CTCAE 4.03. RESULTS: Sixteen patients were enrolled in this study. Of these, 15 were available for evaluation. In these 15 patients, confirmed objective responses were seen in 4 patients [26.67%, 95% confidence interval (CI): 10.9%, 51.95%]. The ORRs did not meet the predefined criteria (of a response by at least 5 of the 15 patients); thus, the study remained at stage I. The median progression-free survival (PFS) was 9.8 weeks; 4 patients had a PFS of >25 weeks. In relation to the treatment-related AEs ≥ grade 3, >2 patients had neutropenia (33%), thrombocytopenia (20%), leucopenia (20%), and vomiting (20%). CONCLUSIONS: The addition of chidamide did not improve the efficacy of cisplatin in the first-line treatment against advanced TNBC; thus, the phase II clinical trial did not progress any further. Our study appears to be the first to investigate the HDAC inhibitor in TNBC patients and showed disappointing results, which should inform future studies. Future research on cisplatin-based combination treatments for TNBC should consider selecting patients based on predictive biomarkers to increase the clinical benefits.

Phase I study of pucotenlimab (HX008), an anti-PD-1 antibody, for patients with advanced solid tumors.

BACKGROUND: Pucotenlimab is a humanized immunoglobulin G4 (IgG4) anti programmed cell death protein 1 (anti-PD-1) monoclonal antibody (mAb) with a S228P hinge mutation and an engineered Fc domain. Preclinical data suggests that pucotenlimab exerts antitumor effects. In this phase I study, which was prospectively registered on www.chinadrugtrials.org.cn (CTR20180125), the safety, maximum tolerated dose, preliminary antitumor activity, pharmacokinetics, and immunogenicity of pucotenlimab were evaluated in patients with advanced solid tumors. METHODS: Patients with advanced solid tumors refractory to standard therapies were recruited. In a 3+3 dose escalation study, 13 patients received pucotenlimab intravenously every 3 weeks (Q3W) until disease progression or unacceptable toxicity occurred at doses of 1 mg/kg, 3 mg/kg, 10 mg/kg, and 200 mg. 17 additional patients were assigned in the expansion period. RESULTS: A total of 30 patients were enrolled. No dose-limiting toxicity was observed. The maximum tolerated dose was not reached. The most common treatment-related adverse events of any grade were proteinuria (40%), fatigue (36.7%), weight loss (26.7%), fever (26.7%), increased aspartate aminotransferase (26.7%), rash (23.3%), and anorexia (20.0%). Partial responses occurred in five patients, with an objective response rate of 16.7%. Pharmacokinetics analysis showed rapid absorption followed by slow terminal elimination, with a mean half-life of 17.1-23.5 days across all dose groups. CONCLUSIONS: Pucotenlimab had an acceptable toxicity profile at doses up to 10 mg/kg and the maximum tolerated dose was not reached. Based on the pharmacokinetics, efficacy, and safety profile, 3 mg/kg Q3W or 200 mg Q3W are optimal for further drug development.

Synergistic antitumor effect of the anti-ErbB2 antibodies trastuzumab and H2-18 on trastuzumab-resistant gastric cancer cells.

Trastuzumab resistance is a severe problem in the treatment of ErbB2-amplified cancer. Although trastuzumab plus pertuzumab is able to partly overcome trastuzumab resistance in ErbB2-overexpressing cancer, its antitumor efficacy remains limited. The present study investigated the antitumor activity of the combination of trastuzumab with H2-18, which is an antibody targetinsg ErbB2 domain I. Cell proliferation and inhibition experiments indicated that H2-18 and trastuzumab synergistically inhibited the proliferation of both the trastuzumab-sensitive gastric cancer cell line, NCI-N87 and the trastuzumab-resistant gastric cancer cell line, NCI-N87-TraRT. Furthermore, H2-18 plus trastuzumab inhibited the growth of NCI-N87-TraRT cells more effectively than trastuzumab plus pertuzumab, both in vitro and in vivo. Compared with trastuzumab plus pertuzumab, H2-18 plus trastuzumab had a potent ability to inhibit NCI-N87-TraRT cells to form colonies. Notably, H2-18 plus trastuzumab was more effective in inducing cell death than trastuzumab plus pertuzumab. The in vivo studies demonstrated that H2-18 plus trastuzumab effectively inhibited the growth of both NCI-N87 and NCI-N87-TraRT xenograft tumors. Further experiments revealed that in NCI-N87-TraRT cells, H2-18 plus trastuzumab was comparable to trastuzumab plus pertuzumab in the inhibition of phosphorylated (p-)HER3, p-AKT and p-ERK. However, compared with trastuzumab plus pertuzumab, H2-18 plus trastuzumab effectively activated ROS production and the phosphorylation of JNK and c-jun in NCI-N87-TraRT cells. Therefore, the superior antitumor efficacy of H2-18 plus trastuzumab over trastuzumab plus pertuzumab may be mainly attributable to the potent cell death-inducing activity. In addition, the in vitro and in vivo antitumor effect of the combination of H2-18, trastuzumab and pertuzumab were further investigated. The results revealed that H2-18 plus trastuzumab plus pertuzumab exhibited a maximal antitumor effect among all the anti-ErbB2 monoclonal antibody combinations tested. In summary, H2-18 plus trastuzumab may have potential as an effective strategy to overcome the resistance to trastuzumab in ErbB2-amplified gastric cancer cell lines.

An integrated bioinformatics analysis to investigate the targets of miR-133a-1 in breast cancer.

BACKGROUND: The microRNA (miRNA) miR-133a-1 has been identified as a tumor suppressor in breast cancer. However, the underlying mechanisms of miR-133a-1 in breast cancer have not been fully elucidated. This study aimed to explore the targets of miR-133a-1 in breast cancer using an integrated bioinformatics approach. METHODS: Human SKBR3 breast cancer cells were transfected with miR-133a-1 or a miRNA negative control (miRNA-NC) for 48 hours. The RNA-seq sequencing technique was performed to identify the differential expression of genes induced by miR-133a-1 overexpression. Functional enrichment analysis was conducted to determine the target genes and pathways involved in breast cancer. RESULTS: Breast cancer patients with high levels of miR-133a-1 expression commonly showed longer overall survival compared to patients with a low level of miR-133a-1 expression. Using Cuffdiff, we identified 1,216 differentially expressed genes induced by miR-133a-1 overexpression, including 653 upregulated and 563 downregulated genes. MOCS3 was the most upregulated gene and KRT14 was the most downregulated gene. The top 10 pathways related to the differentially expressed genes were identified through Gene Ontology (GO) enrichment analysis. Sex-determining region Y-box 9 (SOX9) demonstrated the highest semantic similarities among the differentially expressed genes. Since SOX9 and CD44 were hub nodes in the protein-protein interaction network, the SOX9 gene may be a target of miR-133a-1 in breast cancer. CONCLUSIONS: This report provides useful insights for understanding the underlying mechanisms in the pathogenesis of breast cancer.

MicroRNA-143 targets MAPK3 to regulate the proliferation and bone metastasis of human breast cancer cells.

MicroRNAs (miRs) have shown tremendous potential to act as therapeutic targets for cancer treatment. In this context, the present study was designed to investigate the potential of miR-143 in the treatment of breast cancer. Results showed that miR-143 to be significantly (P < 0.05) downregulated in breast cancer tissues and cell lines. The miR-143 has inhibitory effect on CAMA-1cell growth which was manifested as significant (P < 0.05) decline in loss of viability of cancer cells. The loss of cell viability was revealed to be due to the induction of apoptotic cell death as evident from acridine orange/ethidium bromide (AO/EB) and 4',6-diamidino-2-phenylindole (DAPI) staining assays. The apoptotic cell percentage was found to be 35.7% in miR-143 mimics transfected in comparison to 6.4% in miR-NC transfected cells. The western blot analysis showed that miR-143 caused enhancement in Bax and suppression in Bcl-2 expression in CAMA-1 cells. The miR-143 also suppressed the bone metastasis of the CAMA-1 cells by suppressing the expression of Jag1 and deactivation of the Rho-signalling pathway. The transwell assays also showed considerable anti-metastatic effects of miR-143 on CAMA-1 cells. Taken together, miR-143 has growth inhibitory anti-metastatic effect on breast cancer and thus may prove beneficial in breast cancer treatment.

The function of SOX2 in breast cancer and relevant signaling pathway.

OBJECTIVE: The purpose of this study was to explore the functional roles of SOX2 in the progression of breast cancer and relevant molecular mechanism. METHODS: A total of 108 breast cancer patients were included, and breast cancer cell line MDA-MB-231 was selected for this research. Real time-qualitative polymerase chain reaction (RT-qPCR) was conducted to measure the expression level of SOX2 mRNA. MTT and Transwell assays were used to detected the proliferation, migration and invasion of breast cancer cells, respectively. Luciferase reporter assay was conducted to reveal the relationship of SOX2 with PTEN. Western blot was performed to detect the expressions of Wnt/ß-catenin pathway-related proteins. RESULTS: The expression of SOX2 mRNA was up-regulated in breast cancer tissues and cells (P < 0.001). SOX2 expression was significantly associated with TNM stage and lymph node metastasis of breast cancer patients (P < 0.05). SOX2 knockdown significantly inhibited the proliferation, migration and invasion of breast cancer cells (P < 0.05). PTEN was a direct target of SOX2. The inhibition of PTEN could significantly suppress the progression of breast cancer cells with SOX2 overexpression. SOX2 knockdown also inhibited the expressions of ß-catenin, TCP-4, FZD7, C-myc and MMP-7 proteins. Moreover, PTEN knockdown reversed the results caused by SOX2 overexpression, that is, increased expressions of ß-catenin, TCP-4, FZD7, C-myc and MMP-7 proteins (P < 0.05). CONCLUSION: SOX2 promotes the progression of breast cancer through activating Wnt/ß-catenin signaling pathway via regulating PTEN.

Epigenetic abnormalities of classical Hodgkin lymphoma and its effect on immune escape.

Classical Hodgkin lymphoma (cHL) is a particular kind of malignant tumour that originates from the B cells. The malignant phenotype of cHL is, at least in part, maintained by epigenetic aberrations, which primarily consist of abnormal histone methylation and acetylation. Progress has been made in clinical trials concerning the histone deacetylases inhibitors (HDACis) in cHL. Also, some demethylation regimens could serve the purpose of preventing and treating tumours. Programmed death-ligand receptor 1 (PD-L1, CD274) inhibitors or apoptosis receptor 1 (PD-1, CD279) inhibitors are used in treating patients with relapsed cHL in recent years. Academic researches indicated that PD-1/PD-L1 inhibitors, including nivolumab and pembrolizumab, demonstrate remarkable activity in relapsed cHL. In addition, in recent years, a close association between epigenetic aberrations and immune escape has been explored in cHL. DNA methyltransferase (DNMT) inhibitors, HDACis, and immune checkpoint blockade exhibit synergistic effects. Thus, this review aims to provide an overview on the epigenetic abnormalities of cHL and its effect on immune escape, in order to explore the optimal combination approach to treat the disease. SIGNIFICANCE OF THE STUDY: Cancer Statistics 2018 reported that more than 8000 new cases of Hodgkin lymphoma were diagnosed. In recent years, PD-1/PD-L1 inhibitors for cHL have been utilized, and the therapeutic strategies of HDACis combined with PD-1/PD-L1 inhibitors have been raised. It is critical for improving the efficacy and decreasing the toxicity in treating the patients with cHL.

The anti-ErbB2 antibody H2-18 and the pan-PI3K inhibitor GDC-0941 effectively inhibit trastuzumab-resistant ErbB2-overexpressing breast cancer.

Trastuzumab, an anti-ErbB2 humanized antibody, brings benefit to patients with ErbB2-amplified metastatic breast cancers. However, the resistance to trastuzumab is common. Our previously reported H2-18, an anti-ErbB2 antibody, potently induced programmed cell death in trastuzumab-resistant breast cancer cells. Here, we aim to investigate the antitumor efficacy of H2-18 in combination with the pan-PI3K inhibitor GDC-0941 in trastuzumab-resistant breast cancer cell lines. The results showed that H2-18 and GDC-0941 synergistically inhibited the in vitro proliferation of BT-474, SKBR-3, HCC-1954 and HCC-1419 breast cancer cells. H2-18 plus GDC-0941 showed significantly enhanced programmed cell death-inducing activity compared with each drug used alone. The combination of H2-18 and GDC-0941 did not increase the effect of single agent on ROS production, cell cycle and ErbB2 signaling. Importantly, the in vivo antitumor efficacy of H2-18 plus GDC-0941 was superior to that of single agent. Thus, the enhanced in vivo antitumor efficacy of H2-18 plus GDC-0941 may mainly be attributable to its increased programmed cell death-inducing activity. Collectively, H2-18 plus GDC-0941 could effectively inhibit tumor growth, suggesting the potential to be translated into clinic as an efficient strategy for ErbB2-overexpressing breast cancers.

Combating acquired resistance to trastuzumab by an anti-ErbB2 fully human antibody.

Trastuzumab resistance is a common problem that impedes the effectiveness of trastuzumab in ErbB2-amplified cancers. About 70% of ErbB2-amplified breast cancers do not respond to trastuzumab (de novo resistance), and the majority of the trastuzumab-responsive cancers progress within 1 year (acquired resistance). Different mechanisms exist between de novo and acquired resistance. Innate resistance mechanisms are mainly independent of ErbB2 receptor activity, and acquired resistance involves with alterations depending on ErbB2 activity. We previously reported H2-18, an ErbB2 domain I-specific antibody, which could circumvent de novo resistance to trastuzumab. Here, we modeled the development of acquired resistance by treating human gastric cancer cell line NCI-N87 with trastuzumab to obtain the trastuzumab-resistant subline, NCI-N87-TraRT. Next, we investigated the antitumor efficacy of H2-18 in NCI-N87-TraRT cell line. H2-18 exhibited a significantly greater antitumor activity in NCI-N87-TraRT tumor-bearing nude mice than pertuzumab and trastuzumab, either alone or in combination. The unique ability of H2-18 to overcome acquired resistance may be attributable to its potent programmed cell death-inducing activity, which was probably mediated by RIP1-ROS-JNK-c-Jun pathway. In conclusion, H2-18 may have the potential as an effective agent to circumvent acquired resistance to trastuzumab in ErbB2-overexpressing cancers.

Targeting EGFR/HER2 heterodimerization with a novel anti-HER2 domain II/III antibody.

HER2, a ligand-free tyrosine kinase receptor of the HER family, is frequently overexpressed in breast cancer. The anti-HER2 antibody trastuzumab has shown significant clinical benefits in metastatic breast cancer. Despite the effectiveness of trastuzumab, its efficacy remains variable and often modest. Thus, there is an urgent need to improve ErbB2-targeting therapy. Here, we describe a novel anti-HER2 antibody, 7C3, which was developed using hybridoma technique. Structural analysis confirms that the epitope of this antibody is in domain II/III of HER2. Moreover, a structural conformation change was observed in HER2 in complex with 7C3. Interestingly, this novel anti-HER2 antibody exhibits efficacy in blocking HER2/EGFR heterodimerization and signaling. The results highlight the different function role of HER2 domains and the unique potential of 7C3 to inhibit the HER2/EGFR heterodimer, which may complement current anti-HER2 treatments.

Discovery of acylguanidine oseltamivir carboxylate derivatives as potent neuraminidase inhibitors.

In search of novel anti-influenza agents with higher potency, a series of acylguanidine oseltamivir carboxylate analogues were synthesized and evaluated against influenza viruses (H1N1 and H3N2) in vitro. The representative compounds with strong inhibitory activities (IC50 <40nM) against neuraminidase (NA) were further tested against the NA from oseltamivir-resistant strain (H259Y). Among them, compounds 9 and 17 were potent NA inhibitors that exhibited a 5 and 11-fold increase in activity comparing with oseltamivir carboxylate (2, OC) against the H259Y mutant, respectively. Furthermore, the effect against influenza virus H259Y mutant (H1N1) replication and cytotoxicity assays indicated that compounds 9 and 17 exhibited a 20 and 6-fold increase than the parent compound 2, and had no obvious cytotoxicity in vitro. Moreover, the molecular docking studies revealed that the docking modes of compounds 9 and 17 were different from that of oseltamivir, and the new hydrogen bonds and hydrophobic interaction were formed in this case. This work provided unique insights in the discovery of potent inhibitors against NAs from wild-type and oseltamivir-resistant strains.

Combined SRC inhibitor saracatinib and anti-ErbB2 antibody H2-18 produces a synergistic antitumor effect on trastuzumab-resistant breast cancer.

Despite of the effectiveness of the anti-ErbB2 humanized antibody trastuzumab, trastuzumab resistance emerges as a major and common clinical problem. Thus, circumventing trastuzumab resistance has become an urgent need. Recently, Src inhibitor saracatinib has drawn great attention for its key role in trastuzumab response. As shown in our previous study, H2-18, an anti-ErbB2 antibody, could potently induce programmed cell death (PCD) in trastuzumab-resistant breast cancer cells. Here we combined H2-18 and a Src inhibitor, saracatinib, and studied the antitumor activity of this drug combination in trastuzumab-resistant breast cancer cell lines. The results showed that H2-18 and saracatinib could synergistically inhibit cell proliferation of BT-474, SKBR-3, HCC-1954 and HCC-1419 breast cancer cell lines in vitro. H2-18 plus saracatinib could also inhibit the HCC-1954 tumor growth more effectively in vivo than each drug alone. H2-18 plus saracatinib showed a significantly more potent PCD-inducing activity compared with either H2-18 or saracatinib alone. We conclude that enhanced PCD may contribute to the superior antitumor efficacy of this combination therapy. The combination of H2-18 and SRC inhibitor has the potential to be translated into clinic.

An anti-ErbB2 fully human antibody circumvents trastuzumab resistance.

Trastuzumab, an anti-HER2/ErbB2 humanized antibody, has shown great clinical benefits in ErbB2-positive breast cancer treatment. Despite of its effectiveness, response rate to trastuzumab is limited and resistance is common. Here, we developed a new anti-ErbB2 antibody, denoted as H2-18, which was isolated from a phage display human antibody library. Previous studies have demonstrated that trastuzumab recognizes the juxtamembrane region of domain IV, and pertuzumab, another humanized ErbB2-specific antibody, binds to ErbB2 near the center of domain II. Our crystallographic analysis showed that the epitope recognized by H2-18 is within domain I of the ErbB2 molecule. H2-18 potently induced programmed cell death (PCD) in both trastuzumab-sensitive and -resistant breast cancer cell lines, while trastuzumab and pertuzumab, either used alone or in combination, only exhibits very weak PCD-inducing activity. More importantly, H2-18 could inhibit the growth of trastuzumab-resistant breast cancer cells far more effectively than trastuzumab plus pertuzumab, both in vitro and in vivo. In conclusion, H2-18 shows a unique ability to overcome trastuzumab resistance, suggesting that it has the great potential to be translated to the clinic.

A bispecific anti-ErbB2 antibody potently induces ErbB2 internalization and suppresses ErbB2-overexpressing tumor growth.

The anti-ErbB2 humanized antibody trastuzumab was approved for ErbB2-positive metastatic gastric and gastro-esophageal junction cancer in 2010. Despite the effectiveness of trastuzumab, its efficacy remains variable and often modest. Thus, there is an urgent need to improve ErbB2-targeting therapy. Down-regulation of surface receptors induced by monoclonal antibody (mAb) contributes to its antitumor efficacy. Previous studies have demonstrated that if two anti-ErbB2 mAbs did not compete with each other for binding to ErbB2, the combination of them can enhance ErbB2 internalization. In the present study, we investigated ErbB2 internalization-inducing ability of non-competitive anti-ErbB2 mAb combinations and surprisingly found that most of the mAb combinations tested did not down-regulate ErbB2. Only 4 of 18 non-competitive mAb pairs efficiently induced ErbB2 internalization. Interestingly, although the non-competitive anti-ErbB2 mAbs trastuzumab and pertuzumab, either alone or in combination, were ineffective at inducing ErbB2 internalization, TPL, a bispecific antibody engineered from trastuzumab and pertuzumab, potently down-regulated the ErbB2 molecule. Importantly, TPL exhibited a far greater antitumor effect on ErbB2-overexpressing gastric cancer cell line than trastuzumab plus pertuzumab, suggesting that it may be a promising agent for the treatment of gastric cancer.