1
|
Purohit L, Jones C, Gonzalez T, Castrellon A, Hussein A. The Role of CD4/6 Inhibitors in Breast Cancer Treatment. Int J Mol Sci 2024; 25:1242. [PMID: 38279242 PMCID: PMC10816395 DOI: 10.3390/ijms25021242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 01/12/2024] [Accepted: 01/15/2024] [Indexed: 01/28/2024] Open
Abstract
Over the last decade, treatment paradigms for breast cancer have undergone a renaissance, particularly in hormone-receptor-positive/HER2-negative breast cancer. These revolutionary therapies are based on the selective targeting of aberrancies within the cell cycle. This shift towards targeted therapies has also changed the landscape of disease monitoring. In this article, we will review the fundamentals of cell cycle progression in the context of the new cyclin-dependent kinase inhibitors. In addition to discussing the currently approved cyclin-dependent kinase inhibitors for breast cancer, we will explore the ongoing development and search for predictive biomarkers and modalities to monitor treatment.
Collapse
Affiliation(s)
| | | | | | - Aurelio Castrellon
- Memorial Health System, Pembroke Pines, FL 33024, USA; (L.P.); (C.J.); (T.G.); (A.H.)
| | | |
Collapse
|
2
|
Zhu Z, Zhu Q. Differences in metabolic transport and resistance mechanisms of Abemaciclib, Palbociclib, and Ribociclib. Front Pharmacol 2023; 14:1212986. [PMID: 37475713 PMCID: PMC10354263 DOI: 10.3389/fphar.2023.1212986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 06/27/2023] [Indexed: 07/22/2023] Open
Abstract
Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) play a crucial role in cancer treatment, particularly in breast cancer, and their mechanism of drug resistance is a topic of global interest in research. Hence, it is vital to comprehend the distinctions between various CDK4/6i, including their mechanisms of action and resistance mechanisms. This article aims to summarize the metabolic and transport variations as well as the differences in resistance among the three FDA-approved CDK4/6 inhibitors: Abemaciclib, Palbociclib, and Ribociclib. It also aims to discuss how these differences impact the effectiveness and safety of anticancer drugs. It was conducted in March 2023 to search PubMed, Embase, and Web of Science for literature related to this topic. Despite all being CDK4/6i, differences in their metabolism and transport were found, which are related to their chemical structure. Moreover, there are variations in preclinical pharmacology, pharmacokinetics, and clinical safety and efficacy of the different inhibitors. Genetic mutations, drug tolerance, and other factors may influence CDK4/6 resistance mechanisms. Currently, the resistance mechanisms differences of the three drugs remain largely unknown, and there are differences in the resistance mechanisms among them, necessitating further exploration and research.
Collapse
Affiliation(s)
- Zhimin Zhu
- Department of Pharmaceutics, Shanghai Eighth People’s Hospital, Shanghai, China
| | - Qiongni Zhu
- Department of Pharmacy, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| |
Collapse
|
3
|
Applications and mechanisms of the cyclin-dependent kinase 4/6 inhibitor, PD-0332991, in solid tumors. Cell Oncol (Dordr) 2022; 45:1053-1071. [PMID: 36087253 DOI: 10.1007/s13402-022-00714-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/01/2022] [Indexed: 01/10/2023] Open
Abstract
Abnormal CDK4/6-Rb-E2F signal transduction is a common finding in tumors and is a driving factor for the excessive proliferation of various tumor cells. PD-0332991, a highly specific, small molecule inhibitor for CDK4 and 6, has been shown to inhibit tumor growth by abrogating the phosphorylating capacity of CDK4/6 and suppressing Rb phosphorylation. It has been promoted for the treatment of breast cancer and potentially for other tumor types such as liver cancers, lung cancers and sarcomas. Due to the risk of monotherapy resistance, PD-0332991 is commonly used in combination with other drugs. Such combination treatments have proved able to inhibit tumor proliferation more effectively, induce stronger senescence and apoptosis, and enhance the efficiency of immunotherapy. Therefore, tumor cells with senescence induced by PD-0332991 are now used as ideal screening tools of cytolytic drugs with more efficient and thorough anti-tumor properties. With more extensive understandings about the branching points between senescence and apoptosis, it is possible to refine the dosage of PD-0332991. Better characterization of resistant cells, of inhibitors and of adverse effects such as leukopenia are needed to overcome obstacles in the use of PD-0332991. In this review of PD-0332991 research, we hope to provide guidance of transitions from laboratory findings to clinical applications of PD-0332991 and to facilitate PD-0332991-based multi-inhibitor combination therapies for various tumors.
Collapse
|
4
|
Rampioni Vinciguerra GL, Sonego M, Segatto I, Dall’Acqua A, Vecchione A, Baldassarre G, Belletti B. CDK4/6 Inhibitors in Combination Therapies: Better in Company Than Alone: A Mini Review. Front Oncol 2022; 12:891580. [PMID: 35712501 PMCID: PMC9197541 DOI: 10.3389/fonc.2022.891580] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 04/22/2022] [Indexed: 12/24/2022] Open
Abstract
The cyclin D-CDK4/6 complexes play a pivotal role in controlling the cell cycle. Deregulation in cyclin D-CDK4/6 pathway has been described in many types of cancer and it invariably leads to uncontrolled cell proliferation. Many efforts have been made to develop a target therapy able to inhibit CDK4/6 activity. To date, three selective CDK4/6 small inhibitors have been introduced in the clinic for the treatment of hormone positive advanced breast cancer patients, following the impressive results obtained in phase III clinical trials. However, since their approval, clinical evidences have demonstrated that about 30% of breast cancer is intrinsically resistant to CDK4/6 inhibitors and that prolonged treatment eventually leads to acquired resistance in many patients. So, on one hand, clinical and preclinical studies fully support to go beyond breast cancer and expand the use of CDK4/6 inhibitors in other tumor types; on the other hand, the question of primary and secondary resistance has to be taken into account, since it is now very clear that neoplastic cells rapidly develop adaptive strategies under treatment, eventually resulting in disease progression. Resistance mechanisms so far discovered involve both cell-cycle and non-cell-cycle related escape strategies. Full understanding is yet to be achieved but many different pathways that, if targeted, may lead to reversion of the resistant phenotype, have been already elucidated. Here, we aim to summarize the knowledge in this field, focusing on predictive biomarkers, to recognize intrinsically resistant tumors, and therapeutic strategies, to overcome acquired resistance.
Collapse
Affiliation(s)
- Gian Luca Rampioni Vinciguerra
- Division of Molecular Oncology, Centro di Riferimento Oncologico di Aviano (CRO), Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), National Cancer Institute, Aviano, Italy
- Department of Cancer Biology and Genetics and Comprehensive Cancer Center, The Ohio State University, Columbus, OH, United States
| | - Maura Sonego
- Division of Molecular Oncology, Centro di Riferimento Oncologico di Aviano (CRO), Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), National Cancer Institute, Aviano, Italy
| | - Ilenia Segatto
- Division of Molecular Oncology, Centro di Riferimento Oncologico di Aviano (CRO), Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), National Cancer Institute, Aviano, Italy
| | - Alessandra Dall’Acqua
- Division of Molecular Oncology, Centro di Riferimento Oncologico di Aviano (CRO), Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), National Cancer Institute, Aviano, Italy
| | - Andrea Vecchione
- Department of Clinical and Molecular Medicine, Faculty of Medicine and Psychology, Sant’Andrea Hospital, University of Rome “Sapienza”, Rome, Italy
| | - Gustavo Baldassarre
- Division of Molecular Oncology, Centro di Riferimento Oncologico di Aviano (CRO), Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), National Cancer Institute, Aviano, Italy
| | - Barbara Belletti
- Division of Molecular Oncology, Centro di Riferimento Oncologico di Aviano (CRO), Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), National Cancer Institute, Aviano, Italy
- *Correspondence: Barbara Belletti,
| |
Collapse
|
5
|
Inability to phosphorylate Y88 of p27 Kip1 enforces reduced p27 protein levels and accelerates leukemia progression. Leukemia 2022; 36:1916-1925. [PMID: 35597806 PMCID: PMC9252907 DOI: 10.1038/s41375-022-01598-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 04/26/2022] [Accepted: 05/09/2022] [Indexed: 11/18/2022]
Abstract
The cyclin-dependent kinase (CDK) inhibitor p27Kip1 regulates cell proliferation. Phosphorylation of tyrosine residue 88 (Y88) converts the inhibitor into an assembly factor and activator of CDKs, since Y88-phosphorylation restores activity to cyclin E,A/CDK2 and enables assembly of active cyclin D/CDK4,6. To investigate the physiological significance of p27 tyrosine phosphorylation, we have generated a knock-in mouse model where Y88 was replaced by phenylalanine (p27-Y88F). Young p27-Y88F mice developed a moderately reduced body weight, indicative for robust CDK inhibition by p27-Y88F. When transformed with v-ABL or BCR::ABL1p190, primary p27-Y88F cells are refractory to initial transformation as evidenced by a diminished outgrowth of progenitor B-cell colonies. This indicates that p27-Y88 phosphorylation contributes to v-ABL and BCR::ABL1p190 induced transformation. Surprisingly, p27-Y88F mice succumbed to premature v-ABL induced leukemia/lymphoma compared to p27 wild type animals. This was accompanied by a robust reduction of p27-Y88F levels in v-ABL transformed cells. Reduced p27-Y88F levels seem to be required for efficient cell proliferation and may subsequently support accelerated leukemia progression. The potent downregulation p27-Y88F levels in all leukemia-derived cells could uncover a novel mechanism in human oncogenesis, where reduced p27 levels are frequently observed.
Collapse
|
6
|
Abstract
Cyclin-dependent kinases 4 and 6 (CDK4 and CDK6) and their activating partners, D-type cyclins, link the extracellular environment with the core cell cycle machinery. Constitutive activation of cyclin D–CDK4/6 represents the driving force of tumorigenesis in several cancer types. Small-molecule inhibitors of CDK4/6 have been used with great success in the treatment of hormone receptor–positive breast cancers and are in clinical trials for many other tumor types. Unexpectedly, recent work indicates that inhibition of CDK4/6 affects a wide range of cellular functions such as tumor cell metabolism and antitumor immunity. We discuss how recent advances in understanding CDK4/6 biology are opening new avenues for the future use of cyclin D–CDK4/6 inhibitors in cancer treatment.
Collapse
Affiliation(s)
- Anne Fassl
- Department of Cancer Biology, Dana-Farber Cancer Institute, Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Yan Geng
- Department of Cancer Biology, Dana-Farber Cancer Institute, Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Piotr Sicinski
- Department of Cancer Biology, Dana-Farber Cancer Institute, Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02215, USA
| |
Collapse
|
7
|
Pennycook BR, Barr AR. Palbociclib-mediated cell cycle arrest can occur in the absence of the CDK inhibitors p21 and p27. Open Biol 2021; 11:210125. [PMID: 34784791 PMCID: PMC8596008 DOI: 10.1098/rsob.210125] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 10/26/2021] [Indexed: 01/04/2023] Open
Abstract
The use of CDK4/6 inhibitors in the treatment of a wide range of cancers is an area of ongoing investigation. Despite their increasing clinical use, there is limited understanding of the determinants of sensitivity and resistance to these drugs. Recent data have cast doubt on how CDK4/6 inhibitors arrest proliferation, provoking renewed interest in the role(s) of CDK4/6 in driving cell proliferation. As the use of CDK4/6 inhibitors in cancer therapies becomes more prominent, an understanding of their effect on the cell cycle becomes more urgent. Here, we investigate the mechanism of action of CDK4/6 inhibitors in promoting cell cycle arrest. Two main models explain how CDK4/6 inhibitors cause G1 cell cycle arrest, which differ in their dependence on the CDK inhibitor proteins p21 and p27. We have used live and fixed single-cell quantitative imaging, with inducible degradation systems, to address the roles of p21 and p27 in the mechanism of action of CDK4/6 inhibitors. We find that CDK4/6 inhibitors can initiate and maintain a cell cycle arrest without p21 or p27. This work clarifies our current understanding of the mechanism of action of CDK4/6 inhibitors and has implications for cancer treatment and patient stratification.
Collapse
Affiliation(s)
- Betheney R. Pennycook
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0NN, UK
- MRC London Institute of Medical Sciences, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Alexis R. Barr
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0NN, UK
- MRC London Institute of Medical Sciences, Imperial College London, Du Cane Road, London W12 0NN, UK
| |
Collapse
|
8
|
Jilishitz I, Quiñones JL, Patel P, Chen G, Pasetsky J, VanInwegen A, Schoninger S, Jogalekar MP, Tsiperson V, Yan L, Wu Y, Gottesman SRS, Somma J, Blain SW. NP-ALT, a Liposomal:Peptide Drug, Blocks p27Kip1 Phosphorylation to Induce Oxidative Stress, Necroptosis, and Regression in Therapy-Resistant Breast Cancer Cells. Mol Cancer Res 2021; 19:1929-1945. [PMID: 34446542 DOI: 10.1158/1541-7786.mcr-21-0081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 06/14/2021] [Accepted: 08/17/2021] [Indexed: 11/16/2022]
Abstract
Resistance to cyclin D-CDK4/6 inhibitors (CDK4/6i) represents an unmet clinical need and is frequently caused by compensatory CDK2 activity. Here we describe a novel strategy to prevent CDK4i resistance by using a therapeutic liposomal:peptide formulation, NP-ALT, to inhibit the tyrosine phosphorylation of p27Kip1(CDKN1B), which in turn inhibits both CDK4/6 and CDK2. We find that NP-ALT blocks proliferation in HR+ breast cancer cells, as well as CDK4i-resistant cell types, including triple negative breast cancer (TNBC). The peptide ALT is not as stable in primary mammary epithelium, suggesting that NP-ALT has little effect in nontumor tissues. In HR+ breast cancer cells specifically, NP-ALT treatment induces ROS and RIPK1-dependent necroptosis. Estrogen signaling and ERα appear required. Significantly, NP-ALT induces necroptosis in MCF7 ESRY537S cells, which contain an ER gain of function mutation frequently detected in metastatic patients, which renders them resistant to endocrine therapy. Here we show that NP-ALT causes necroptosis and tumor regression in treatment naïve, palbociclib-resistant, and endocrine-resistant BC cells and xenograft models, demonstrating that p27 is a viable therapeutic target to combat drug resistance. IMPLICATIONS: This study reveals that blocking p27 tyrosine phosphorylation inhibits CDK4 and CDK2 activity and induces ROS-dependent necroptosis, suggesting a novel therapeutic option for endocrine and CDK4 inhibitor-resistant HR+ tumors.
Collapse
Affiliation(s)
- Irina Jilishitz
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, New York
| | - Jason Luis Quiñones
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, New York
| | - Priyank Patel
- Concarlo Holdings, LLC, Downstate Biotechnology Incubator, Brooklyn, New York
| | - Grace Chen
- Concarlo Holdings, LLC, Downstate Biotechnology Incubator, Brooklyn, New York
| | - Jared Pasetsky
- College of Medicine, SUNY Downstate Medical Center, Brooklyn, New York
| | - Allison VanInwegen
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, New York
| | - Scott Schoninger
- College of Medicine, SUNY Downstate Medical Center, Brooklyn, New York
| | - Manasi P Jogalekar
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, New York
| | - Vladislav Tsiperson
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, New York
| | - Lingyue Yan
- Department of Biomedical Engineering, University at Buffalo, The State University at Buffalo, Buffalo, New York
| | - Yun Wu
- Department of Biomedical Engineering, University at Buffalo, The State University at Buffalo, Buffalo, New York
| | - Susan R S Gottesman
- Department of Pathology and Cell Biology, SUNY Downstate Medical Center, Brooklyn, New York
| | - Jonathan Somma
- Department of Pathology, Louisiana State University Health Sciences Center, New Orleans, Los Angeles
| | - Stacy W Blain
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, New York.
| |
Collapse
|
9
|
Li K, Huang Z, Tian S, Chen Y, Yuan Y, Yuan J, Zou X, Zhou F. MicroRNA-877-5p alleviates ARDS via enhancing PI3K/Akt path by targeting CDKN1B both in vivo and in vitro. Int Immunopharmacol 2021; 95:107530. [PMID: 33735715 DOI: 10.1016/j.intimp.2021.107530] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 02/17/2021] [Accepted: 02/22/2021] [Indexed: 01/19/2023]
Abstract
Acute respiratory distress syndrome (ARDS) is a public health problem with high morbidity and mortality worldwide due to lacking known characteristic biomarkers and timely intervention. Pulmonary edema caused by inflammation and pulmonary microvascular endothelial cell disfunction is the main pathophysiological change of ARDS. Circulating microRNAs (miRNAs) are differentially expressed between subjects who did and did not develop ARDS. Many miRNAs have been exemplified to be involved in ARDS and could represent the novel therapeutic targets, but the role of microRNA-877-5p (miR-877-5p) in ARDS and its regulatory mechanisms are still unknown. Herein, we explore the underlying function of miR-877-5p toward anesis of ARDS and addressed that miRNA-877 can reduce the release of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 thus attenuating the damage of pulmonary microvascular endothelial cells (HPMECs). Have further evaluated the protein expression, we detected that miR-877-5p contributed to the relief of ARDS by suppressing Cyclin-dependent kinase inhibitor 1B (CDKN1B), which serves as a regulator of endothelial cell polarization and migration through phosphatidylinositol-3-kinase and AKT (PI3K/Akt) signaling pathway. Besides, we noticed that CDKN1B restrains cell differentiation by inhibiting Cdk2 (cyclin-dependent kinase 2), instead of Cdk4 (cyclin-dependent kinase 4), during which the nuclear translocation of CDKN1B may participate. Together, our works testified that miR-877-5p might suppress inflammatory responses and promote HPMECs regeneration via targeting CDKN1B by modulation of Cdk2 and PI3K/Akt path. These molecules likely modulating ARDS progression may inform biomarkers and therapeutic development.
Collapse
Affiliation(s)
- Kaili Li
- Department of Critical Care Medicine, the First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, PR China.
| | - Zuoting Huang
- Department of Hepatobiliary Surgery, the First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, PR China.
| | - Shijing Tian
- Department of Critical Care Medicine, the First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, PR China.
| | - Yi Chen
- Department of Critical Care Medicine, the First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, PR China.
| | - Yuan Yuan
- Department of Critical Care Medicine, the First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, PR China.
| | - Jianghan Yuan
- Department of Critical Care Medicine, the First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, PR China.
| | - Xuan Zou
- Department of Critical Care Medicine, the First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, PR China.
| | - Fachun Zhou
- Department of Critical Care Medicine, the First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, PR China.
| |
Collapse
|
10
|
Álvarez-Fernández M, Malumbres M. Mechanisms of Sensitivity and Resistance to CDK4/6 Inhibition. Cancer Cell 2020; 37:514-529. [PMID: 32289274 DOI: 10.1016/j.ccell.2020.03.010] [Citation(s) in RCA: 178] [Impact Index Per Article: 44.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/04/2020] [Accepted: 03/12/2020] [Indexed: 12/25/2022]
Abstract
Inhibiting the cell-cycle kinases CDK4 and CDK6 results in significant therapeutic effect in patients with advanced hormone-positive breast cancer. The efficacy of this strategy is, however, limited by innate or acquired resistance mechanisms and its application to other tumor types is still uncertain. Here, through an integrative analysis of sensitivity and resistance mechanisms, we discuss the use of CDK4/6 inhibitors in combination with available targeted therapies, immunotherapy, or classical chemotherapy with the aim of improving future therapeutic uses of CDK4/6 inhibition in a variety of cancers.
Collapse
Affiliation(s)
- Mónica Álvarez-Fernández
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), Melchor Fernández Almagro 3, 28029 Madrid, Spain
| | - Marcos Malumbres
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), Melchor Fernández Almagro 3, 28029 Madrid, Spain.
| |
Collapse
|
11
|
Schoninger SF, Blain SW. The Ongoing Search for Biomarkers of CDK4/6 Inhibitor Responsiveness in Breast Cancer. Mol Cancer Ther 2020; 19:3-12. [PMID: 31909732 PMCID: PMC6951437 DOI: 10.1158/1535-7163.mct-19-0253] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 08/02/2019] [Accepted: 09/05/2019] [Indexed: 12/20/2022]
Abstract
CDK4 inhibitors (CDK4/6i), such as palbociclib, ribociclib, and abemaciclib, are approved in combination with hormonal therapy as a front-line treatment for metastatic HR+, HER2- breast cancer. Their targets, CDK4 and CDK6, are cell-cycle regulatory proteins governing the G1-S phase transition across many tissue types. A key challenge remains to uncover biomarkers to identify those patients that may benefit from this class of drugs. Although CDK4/6i addition to estrogen modulation therapy essentially doubles the median progression-free survival, overall survival is not significantly increased. However, in reality only a subset of treated patients respond. Many patients exhibit primary resistance to CDK4/6 inhibition and do not derive any benefit from these agents, often switching to chemotherapy within 6 months. Some patients initially benefit from treatment, but later develop secondary resistance. This highlights the need for complementary or companion diagnostics to pinpoint patients who would respond. In addition, because CDK4 is a bona fide target in other tumor types where CDK4/6i therapy is currently in clinical trials, the lack of target identification may obscure benefit to a subset of patients there as well. This review summarizes the current status of CDK4/6i biomarker test development, both in clinical trials and at the bench, with particular attention paid to those which have a strong biological basis as well as supportive clinical data.
Collapse
Affiliation(s)
| | - Stacy W Blain
- Departments of Pediatrics and Cell Biology, SUNY Downstate Medical Center, Brooklyn, New York.
| |
Collapse
|