Han-Chung Wu's Lab｜Institute of Cellular and Organismic Biology, Academia Sinica

1. Development of Novel Drug Delivery Systems for Cancer Molecular Imaging and Therapy  

     Cancer is one of the most common causes of mortality, accounting for more than 8 million annual deaths worldwide. Advances of medical science in the treatment of cancer have reached a bottleneck due to several major obstacles, including drug resistance, poor drug penetration through the high interstitial fluid pressure (IFP) of solid tumors, and the resilience of cancer stem cells. To overcome these obstacles, our lab is developing ligand-mediated targeted therapies for cancer (Fig. 1). This strategy can improve the therapeutic efficacies of cancer treatments by increasing drug accumulation in the tumor tissue and reducing drug side effects by limiting drug distribution and damage to normal tissues. Since targeted delivery of small molecules to tumors can be useful to improve both cancer diagnosis and therapy, development of novel tumor-specific ligands or pharmaceutical nanocarriers is highly desirable. In particular, peptide-mediated targeting holds great promise for incorporation into novel cancer therapies, as it has been shown to increase tumor specificity and limit toxicity. Our research on this topic has been published in Cancer Letters 2015, Nanomedicine 2015, Science Translational Medicine 2015, Biomaterials 2016, Theranostics 2017, Oral Oncology 2020 and Cancer Research 2021.

Colorectal cancer is one of the most commonly diagnosed cancers. We have successfully identified a novel targeting peptide that specifically binds to colorectal cancer cells, pHCT74. Research results on this peptide have been published in top translational medical journals. We further found that the molecular target of pHCT74 peptide is α-enolase (ENO1). This led us to discover that ENO1 binds to HGFR, which promotes lung cell invasion, tumor metastasis and progression through the HGFR-Src-PI3K-AKT-GSK3β-SLUG and HGFR-WNT-GSK3β-SLUG signaling axes. We then generated a novel monoclonal antibody (mAb) against ENO1, called chimeric ENO1-22 (chENO1-22), which can bind to ENO1 on the surface of lung cancer cells. Treatment with chENO1-22 reduced lung cancer cell growth and invasion, and importantly, chENO1-22 blocked metastasis and improved survival in mouse models (Fig. 2). This study showed that ENO1 promotes lung cancer metastasis via HGFR and WNT signaling, and it further introduced a novel anti-ENO1 antibody for potential therapeutic use in lung cancer (Cancer Research 2021).

Lung cancer is the leading cause of cancer-related death worldwide. Three targeting phages (HPC1, HPC2, and HPC4) and their respective displayed peptides (HSP1, HSP2, and HSP4) were able to bind to both small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) cell lines, as well as clinical specimens; however the peptides did not bind normal pneumonic tissues. Liposomal doxorubicin (LD) conjugated to HSP1, HSP2, or HSP4 had significantly greater therapeutic efficacy than non-targeting liposomal drugs in NSCLC xenograft (H460 and H1993) animal models (Fig. 3). In vivo optical imaging of phage homing and magnetic resonance imaging (MRI) of peptide-SPIONs revealed that HSP1 was the most favorable probe for multimodal molecular imaging of lung cancer (Theranostics 2017). 

2. EpCAM Signaling Promotes Tumor Progression through the EGFR Pathway

Although epithelial cell adhesion molecule (EpCAM) has previously been shown to promote tumor progression, the underlying mechanisms remain largely unknown. In this study, we report that the EGF-like domain I within the extracellular domain of EpCAM (EpEX) binds EGFR, activating both AKT and MAPK signaling to inhibit forkhead transcription factor O3a (FOXO3a) function and stabilize PD-L1 protein, respectively. Treatment with the EpCAM neutralizing antibody, EpAb2-6, inhibited AKT and FOXO3a phosphorylation, increased FOXO3a nuclear translocation, and upregulated high temperature requirement A2 (HtrA2) expression to promote apoptosis, while decreasing PD-L1 protein levels to enhance the cytotoxic activity of CD8+ T cells. In in vivo studies, EpAb2-6 markedly extended survival in metastasis and orthotopic mouse models of human colorectal cancer. The combination of EpAb2-6 with atezolizumab, an anti-PD-L1 antibody, almost completely eliminated tumors. Moreover, the number of CD8+ T cells in combination-treated tumors was increased compared with atezolizumab alone. Our findings suggest a new combination strategy for cancer immunotherapy in patients with EpCAM-expressing tumors (Fig. 4). The study showed that EpCAM acts through growth factor signaling to stabilize another cell-surface molecule, PD-L1, which allows tumor cells to escape recognition by the patient’s immune system. Most importantly, a new neutralizing antibody was able to prevent EpCAM signaling and decrease the level of PD-L1 in cancer cells, leading to cancer cell death through this and other mechanisms. These results have been published in Cancer Letters 2018 and Cancer Research 2020.

3. Development of antibodies for treatment and detection of SARS-CoV-2

SARS-CoV-2 rapidly spread to cause the severe worldwide COVID-19 pandemic after the initial outbreak at the end of 2019. One promising therapeutic strategy for COVID-19 is treatment with neutralizing antibodies, which can reduce the viral load to prevent disease progression and accelerate patient recovery. We have successfully created a series of generated therapeutic antibodies against SARS-CoV-2 RBD protein, of which six have high binding and excellent neutralizing activity toward SARS-CoV-2. Importantly, these six anti-RBD antibodies target three distinct non-overlapping epitopes within the RBD, and cryo-electron microscopy analyses of two highly potent antibodies in complex with the SARS-CoV-2 spike protein suggested they may be particularly useful when combined in a cocktail therapy (Fig. 5). The efficacy of this antibody cocktail was confirmed in SARS-CoV-2-infected mouse and hamster models as prophylactic and post-infection treatments (Fig. 6). With the emergence of more contagious variants of SARS-CoV-2, cocktail antibody therapies hold great promise for control of the disease and prevention of drug resistance (PLOS Pathogens 2021 JBMS 2021).

New sensitive, rapid diagnostic tests for the wide-spectrum detection of SARS-COV-2 variants are needed. To create such tests, we generated a panel of 41 monoclonal antibodies against the SARS-CoV-2 nucleocapsid protein (NP) using mouse hybridoma techniques. Of these mAbs, nine exhibited high binding activities and were applied in latex-based lateral flow immunoassays (LFIAs). The LFIAs utilizing NP-mAb-7 and -40 had the best sensitivity and lowest limit of detection: 8 pg for purified NP and 625 TCID50/mL for the authentic virus (hCoV-19/Taiwan/4/2020). Specificity tests further showed that the NP-mAb-40/7 LFIA strips did not cross-react with five human coronavirus strains or 20 other common respiratory pathogens. Importantly, we found that 10 NP mutants, including alpha, beta, gamma, and delta variants, could be detected by NP-mAb-40/7 LFIA strips. A clinical study (n = 60) of the NP-mAb-40/7 LFIA strips demonstrated a specificity of 100% and sensitivity of 90% in infected individuals with cycle threshold (Ct) values < 30 (IJMS 2021). Based on the data from this clinical study, the NP-mAb-40/7 LFIA was granted Emergency Use Authorization (EUA) by TFDA on July 8, 2021, making it the first test from Academia Sinica to gain approval for use in the population (brand name: Acadecise COVID-19 antigen rapid test) (Fig. 7).

Notably, detection of serum antibodies IgG/IgM can be used to estimate the time sequence of infection, which is helpful for epidemic prevention and investigations.We began a cooperation with Tzu-Chi University at the beginning of the outbreak to develop serology tests for the detection of IgM and IgG against SARS-CoV-2. The test was granted an EUA by TFDA on July 27, 2020. To date, 195,000 of these rapid serological antibody tests have been delivered to developing countries, such as Indonesia, Honduras, Bolivia, Dominican Republic, Saint Lucia, and Lesotho. The tests were distributed for the purpose of international humanitarian assistance and in the spirit of “Taiwan Is Helping”.