• Journal of Life Science
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• v.29 no.4
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• pp.499-508
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• 2019

Cancer stem cells (CSCs), which are primarily responsible for metastasis and recurrence, have self-renewal, differentiation, therapeutic resistance, and tumor formation abilities. Numerous studies have demonstrated the signaling pathways essential for the acquisition and maintenance of CSC characteristics, such as WNT/${\beta}$-catenin, Hedgehog, Notch, B lymphoma Mo-MLV insertion region 1 homolog (BMI1), Bone morphogenetic protein (BMP), and TGF-${\beta}$ signals. However, few therapeutic strategies have been developed that can selectively eliminate CSCs. Recently, neutralizing antibodies against Cytotoxic T-lymphocyte associated protein 4 (CTLA-4) and Programmed cell death protein 1 (PD-1)/Programmed death-ligand 1 (PD-L1), immune checkpoint inhibitors (ICIs), have shown promising outcomes in clinical trials of melanoma, lung cancer, and pancreatic cancer, as well as in hematologic malignancies. ICIs are considered to outperform conventional anticancer drugs by maintaining long-lasting anti-cancer effects, with less severe side effects. Several studies reported that ICIs successfully blocked CSC properties in head and neck squamous carcinomas, melanomas, and breast cancer. Together, these findings suggest that novel and effective anticancer therapeutic modalities using ICIs for selective elimination of CSCs may be developed in the near future. In this review, we highlight the origin and characteristics of CSCs, together with critical signaling pathways. We also describe progress in ICI-mediated anticancer treatment to date and present perspectives on the development of CSC-targeting ICIs.

• IMMUNE NETWORK
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• v.20 no.1
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• pp.10.1-10.14
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• 2020

Immune checkpoint inhibitors (ICIs) have shown remarkable benefit in the treatment of patients with non-small-cell lung cancer (NSCLC) and have emerged as an effective treatment option even in the first-line setting. ICIs can block inhibitory pathways that restrain the immune response against cancer, restoring and sustaining antitumor immunity. Currently, there are 4 PD-1/PD-L1 blocking agents available in clinics, and immunotherapy-based regimen alone or in combination with chemotherapy is now preferred option. Combination trials assessing combination of ICIs with chemotherapy, targeted therapy and other immunotherapy are ongoing. Controversies remain regarding the use of ICIs in targetable oncogene-addicted subpopulations, but their initial treatment recommendations remained unchanged, with specific tyrosine kinase inhibitors as the choice. For the majority of patients without targetable driver oncogenes, deciding between therapeutic options can be difficult due to lack of direct cross-comparison studies. There are continuous efforts to find predictive biomarkers to find those who respond better to ICIs. PD-L1 protein expressions by immunohistochemistry and tumor mutational burden have emerged as most well-validated biomarkers in multiple clinical trials. However, there still is a need to improve patient selection, and to establish the most effective concurrent or sequential combination therapies in different NSCLC clinical settings. In this review, we will introduce currently used ICIs in NSCLC and analyze most recent trials, and finally discuss how, when and for whom ICIs can be used to provide promising avenues for lung cancer treatment.

• IMMUNE NETWORK
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• v.15 no.2
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• pp.58-65
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• 2015

Melanoma is the most aggressive skin cancer and its incidence is gradually increasing worldwide. Patients with metastatic melanoma have a very poor prognosis (estimated 5-year survival rate of <16%). In the last few years, several drugs have been approved for malignant melanoma, such as tyrosine kinase inhibitors and immune checkpoint blockades. Although new therapeutic agents have improved progression-free and overall survival, their use is limited by drug resistance and drug-related toxicity. At the same time, adoptive cell therapy of metastatic melanoma with tumor-infiltrating lymphocytes has shown promising results in preclinical and clinical studies. In this review, we summarize the currently available drugs for treatment of malignant melanoma. In addition, we suggest cytokine-induced killer (CIK) cells as another candidate approach for adoptive cell therapy of melanoma. Our preclinical study and several previous studies have shown that CIK cells have potent anti-tumor activity against melanomas in vitro and in an in vivo human tumor xenograft model without any toxicity.

• Journal of Gastric Cancer
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• v.18 no.1
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• pp.1-19
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• 2018

Gastric cancer (GC) is the second leading cause of cancer mortality and the fourth most commonly diagnosed malignant diseases. While continued efforts have been focused on GC treatment, the introduction of trastuzumab marked the beginning of a new era of target-specific treatments. Considering the diversity of mutations in GC, satisfactory results obtained from various target-specific therapies were expected, yet most of them were unsuccessful in controlled clinical trials. There are several possible reasons underlying the failures, including the absence of patient selection depending on validated predictive biomarkers, the inappropriate combination of drugs, and tumor heterogeneity. In contrast to targeted agents, immuno-oncologic agents are designed to regulate and boost immunity, are not target-specific, and may overcome tumor heterogeneity. With the successful establishment of predictive biomarkers, including Epstein-Barr virus pattern, microsatellite instability status, and programmed death-ligand 1 (PD-L1) expression, as well as ideal combination regimens, a new frontier in the immuno-oncology of GC treatment is on the horizon. Since the field of immuno-oncology has witnessed innovative, practice-changing successes in other cancer types, several trials on GC are ongoing. Among immuno-oncologic therapies, immune checkpoint inhibitors are the mainstay of clinical trials performed on GC. In this article, we review target-specific agents currently used in clinics or are undergoing clinical trials, and highlight the future clinical application of immuno-oncologic agents in inoperable GC.

• Development and Reproduction
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• v.18 no.1
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• pp.65-71
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• 2014

Cell cycle process is regulated by a number of protein kinases and among them, serine/threonine kinases carry phosphate group from ATP to substrates. The most important three kinase families are Cyclin-dependent kinase (Cdk), Polo-like kinase (Plk), and Aurora kinase. Polo-like kinase family consists of 5 members (Plk1-Plk5) and they are involved in multiple functions in eukaryotic cell division. It regulates a variety of aspects such as, centrosome maturation, checkpoint recovery, spindle assembly, cytokinesis, apoptosis and many other features. Recently, it has been reported that Plks are related to tumor development and over-expressed in many kinds of tumor cells. When injected the anti-Plk antibody into human cells, the cells show aneuploidy, and if inhibit Plks, most of the mitotic cell division does not proceed properly. For that reasons, many inhibitors of Plk have been recently emerged as new target for remedy of the cancer therapeutic research. In this paper, we reviewed briefly the characteristics of Plk families and how Plks work in regulating cell cycles and cancer formation, and the possibilities of Plks as target for cancer therapy.

• Biomolecules & Therapeutics
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• v.28 no.1
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• pp.1-17
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• 2020

Myeloid-derived suppressor cells (MDSCs) are immature myeloid cells that exert suppressive function on the immune response. MDSCs expand in tumor-bearing hosts or in the tumor microenvironment and suppress T cell responses via various mechanisms, whereas a reduction in their activities has been observed in autoimmune diseases or infections. It has been reported that the symptoms of various diseases, including malignant tumors, can be alleviated by targeting MDSCs. Moreover, MDSCs can contribute to patient resistance to therapy using immune checkpoint inhibitors. In line with these therapeutic approaches, diverse oligonucleotide-based molecules and small molecules have been evaluated for their therapeutic efficacy in several disease models via the modulation of MDSC activity. In the current review, MDSC-targeting oligonucleotides and small molecules are briefly summarized, and we highlight the immunomodulatory effects on MDSCs in a variety of disease models and the application of MDSC-targeting molecules for immuno-oncologic therapy.

• Tuberculosis and Respiratory Diseases
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• v.84 no.2
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• pp.89-95
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• 2021

Lung cancer is one of the leading causes of cancer-related deaths in Korea. Although the smoking rate has decreased over time, the prevalence of lung cancer still remains high. In this study, we reviewed recent trends on the incidence, epidemiology, screening, diagnosis, and treatment of lung cancer in Korea by analyzing data from the national lung cancer registry and recently-published studies. Although approximately 40% of patients with non-small cell lung cancer (NSCLC) were diagnosed as stage IV, the 5-year relative survival rate improved from 11.3% (1993-1995) to 30.2% (2013-2017), possibly due to advances in methods of diagnosis and therapy. In addition, the 2019 implementation of the national lung cancer screening program with low-dose computed tomography may have also contributed to these improvements in survival rates. Recently, molecular diagnosis has become more widely used in the identification of genetic mutations in tissue specimens. Target therapy and immune checkpoint inhibitors have also been successfully used, particularly in cases of advanced NSCLC. In the future, further research on the optimal management of lung cancer remains necessary.

• Korean Journal of Head & Neck Oncology
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• v.37 no.2
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• pp.11-17
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• 2021

Head and neck cancer is the 6^th most frequently diagnosed solid tumor in the world. Alcohol consumption, smoking, and HPV infection are associated with the incidence of head and neck squamous cell carcinoma (HNSCC). Although a multidisciplinary approach is a key strategy for the treatment of locally advanced HNSCC, systemic therapy is the mainstream of recurrent or metastatic HNSCC treatment. Stage IV HNSCC has a relatively poor prognosis with median overall survival of around one year. There have been many clinical trials to investigate the efficacy of target agents in the treatment of HNSCC. In the HPV-negative HNSCC, TP53 and CDKN2A are the most commonly mutated genes. In the HPV-positive HNSCC, the PI3K pathway is frequently altered. EGFR, PI3K, cell cycle pathway, MET, HRAS, and IL6/JAK/STAT pathway are explored targets in HNSCC. In this study, we review the target pathways and agents under research. We also introduce here umbrella trials of recurrent or metastatic HNSCC conducted by the Korea Cancer Study Group. The combination of target agents with immune checkpoint inhibitors or cytotoxic chemotherapies would be a future step in the precision medicine of HNSCC treatment.

• Tuberculosis and Respiratory Diseases
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• v.86 no.1
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• pp.1-13
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• 2023

Lung cancer ranks first in cancer mortality in Korea and cancer incidence in Korean men. More than half of Korean lung cancer patients undergo chemotherapy, including adjuvant therapy. Cytotoxic agents, targeted therapy, and immune checkpoint inhibitors are used in chemotherapy according to the biopsy and genetic test results. Among chemotherapy, the one that has developed rapidly is targeted therapy. The National Comprehensive Cancer Network (NCCN) guidelines have been updated recently for targeted therapy of multiple gene mutations, and targeted therapy is used not only for chemotherapy but also for adjuvant therapy. While previously targeted therapies have been developed for common genetic mutations, recently targeted therapies have been developed to overcome uncommon mutations or drug resistance that have occurred since previous targeted therapy. Therefore, this study describes recent, rapidly developing targeted therapies.

• Korean Journal of Radiology
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• v.22 no.11
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• pp.1822-1833
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• 2021

This is a narrative review of various treatment modalities for advanced hepatocellular carcinoma (HCC), with a focus on recent updates in radiological treatments, as well as novel treatment concepts related to immune checkpoint inhibitors and combination therapies with locoregional treatments. Interventional radiologists have made efforts toward developing alternative and/or combination treatments for first-line systemic treatment of patients with advanced HCC. Locoregional treatments with or without systemic therapy may be considered in the selected patients. Various treatment modalities for advanced HCC are emerging, and several randomized controlled trials, including those of combination treatments with immunotherapy, are ongoing.