RESUMO
Interest in harnessing natural killer (NK) cells for cancer immunotherapy is rapidly growing. However, efficacy of NK cell-based immunotherapy remains limited in most trials. Strategies to augment the killing efficacy of NK cells are thus much needed. In the current study, we found that mitochondrial apoptosis (mtApoptosis) pathway is essential for efficient NK killing, especially at physiologically relevant effector-to-target ratios. Furthermore, NK cells can prime cancer cells for mtApoptosis and mitochondrial priming status affects cancer-cell susceptibility to NK-mediated killing. Interestingly, pre-activating NK cells confers on them resistance to BH3 mimetics. Combining BH3 mimetics with NK cells synergistically kills cancer cells in vitro and suppresses tumor growth in vivo. The ideal BH3 mimetic to use in such an approach can be predicted by BH3 profiling. We herein report a rational and precision strategy to augment NK-based immunotherapy, which may be adaptable to T cell-based immunotherapies as well.
Assuntos
Imunoterapia , Células Matadoras Naturais , Neoplasias/terapia , Apoptose , Neoplasias/patologiaRESUMO
Aurora kinases (AURKs) are mitotic kinases important for regulating cell cycle progression. Small-molecule inhibitors of AURK have shown promising antitumor effects in multiple cancers; however, the utility of these inhibitors as inducers of cancer cell death has thus far been limited. Here, we examined the role of the Bcl-2 family proteins in AURK inhibition-induced apoptosis in colon cancer cells. We found that alisertib and danusertib, two small-molecule inhibitors of AURK, are inefficient inducers of apoptosis in HCT116 and DLD-1 colon cancer cells, the survival of which requires at least one of the two antiapoptotic Bcl-2 family proteins, Bcl-xL and Mcl-1. We further identified Bcl-xL as a major suppressor of alisertib- or danusertib-induced apoptosis in HCT116 cells. We demonstrate that combination of a Bcl-2 homology (BH)3-mimetic inhibitor (ABT-737), a selective inhibitor of Bcl-xL, Bcl-2, and Bcl-w, with alisertib or danusertib potently induces apoptosis through the Bcl-2 family effector protein Bax. In addition, we identified Bid, Puma, and Noxa, three BH3-only proteins of the Bcl-2 family, as mediators of alisertib-ABT-737-induced apoptosis. We show while Noxa promotes apoptosis by constitutively sequestering Mcl-1, Puma becomes associated with Mcl-1 upon alisertib treatment. On the other hand, we found that alisertib treatment causes activation of caspase-2, which promotes apoptosis by cleaving Bid into truncated Bid, a suppressor of both Bcl-xL and Mcl-1. Together, these results define the Bcl-2 protein network critically involved in AURK inhibitor-induced apoptosis and suggest that BH3-mimetics targeting Bcl-xL may help overcome resistance to AURK inhibitors in cancer cells.
Assuntos
Antineoplásicos , Apoptose , Aurora Quinases , Proteína bcl-X , Humanos , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Apoptose/genética , Proteínas Reguladoras de Apoptose/antagonistas & inibidores , Proteínas Reguladoras de Apoptose/metabolismo , Aurora Quinases/antagonistas & inibidores , Proteína X Associada a bcl-2/metabolismo , Proteína bcl-X/antagonistas & inibidores , Proteína bcl-X/metabolismo , Linhagem Celular Tumoral , Neoplasias do Colo/tratamento farmacológico , Neoplasias do Colo/fisiopatologia , Ativação Enzimática/efeitos dos fármacos , Células HCT116 , Proteína de Sequência 1 de Leucemia de Células Mieloides/antagonistas & inibidores , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-bcl-2/metabolismoRESUMO
The anti-apoptotic BCL-2 protein family regulates cancer cell survival, thus it represents an important therapeutic target. Indeed, a drug class, called BH3-mimetics, have been developed to directly target BCL2 proteins and promote cancer cell death. Conventional wisdom suggests that the primary anti-cancer effect of BCL-2 inhibition is through induction of cancer cell death. However, a recent study by Zhao and colleagues describes that BCL-2 inhibition also enhances the function of classical dendritic cells, unleashing their role in immunosurveillance, promoting T cell immunity and tumour regression. Thus, inhibiting anti-apoptotic BCL-2 function may have a multi-pronged anti-tumour action.
Assuntos
Antineoplásicos , Neoplasias , Humanos , Apoptose , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Proteínas Reguladoras de Apoptose/farmacologia , Proteínas Reguladoras de Apoptose/uso terapêutico , Linhagem Celular TumoralRESUMO
Chronic myeloid leukemia (CML) was considered for a long time one of the most hostile leukemia that was incurable for most of the patients, predominantly due to the extreme resistance to chemotherapy. Part of the resistance to cell death (apoptosis) is the result of increased levels of anti-apoptotic and decreased levels of pro-apoptotic member of the BCL-2 family induced by the BCR-ABL1 oncoprotein. BCR-ABL1 is a constitutively active tyrosine kinase responsible for initiating multiple and oncogenic signaling pathways. With the development of specific BCR-ABL1 tyrosine kinase inhibitors (TKIs) CML became a much more tractable disease. Nevertheless, TKIs do not cure CML patients and a substantial number of them develop intolerance or become resistant to the treatment. Therefore, novel anti-cancer strategies must be developed to treat CML patients independently or in combination with TKIs. Here, we will discuss the mechanisms of BCR-ABL1-dependent and -independent resistance to TKIs and the use of BH3-mimetics as a potential tool to fight CML.
Assuntos
Resistencia a Medicamentos Antineoplásicos , Leucemia Mielogênica Crônica BCR-ABL Positiva , Inibidores de Proteínas Quinases , Humanos , Resistencia a Medicamentos Antineoplásicos/genética , Proteínas de Fusão bcr-abl/genética , Proteínas de Fusão bcr-abl/metabolismo , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Transdução de SinaisRESUMO
Recent advances in melanoma therapy have significantly improved the prognosis of metastasized melanoma. However, large therapeutic gaps remain that need to be closed by new strategies. Antiapoptotic Bcl-2 proteins critically contribute to apoptosis deficiency and therapy resistance. They can be targeted by BH3 mimetics, small molecule antagonists that mimic the Bcl-2 homology domain 3 (BH3) of proapoptotic BH3-only proteins. By applying in vitro experiments, we aimed to obtain an overview of the possible suitability of BH3 mimetics for future melanoma therapy. Thus, we investigated the effects of ABT-737 and ABT-263, which target Bcl-2, Bcl-xL and Bcl-w as well as the Bcl-2-selective ABT-199 and the Mcl-1-selective S63845, in a panel of four BRAF-mutated and BRAF-WT melanoma cell lines. None of the inhibitors showed significant effectiveness when used alone; however, combination of S63845 with each one of the three ABTs almost completely abolished melanoma cell survival and induced apoptosis in up to 50-90% of the cells. Special emphasis was placed here on the understanding of the downstream pathways involved, which may allow improved applications of these strategies. Thus, cell death induction was correlated with caspase activation, loss of mitochondrial membrane potential, phosphorylation of histone H2AX, and ROS production. Caspase dependency was demonstrated by a caspase inhibitor, which blocked all effects. Upregulation of Mcl-1, induced by S63845 itself, as reported previously, was blocked by the combinations. Indeed, Mcl-1, as well as XIAP (X-linked inhibitor of apoptosis), were strongly downregulated by combination treatments. These findings demonstrate that melanoma cells can be efficiently targeted by BH3 mimetics, but the right combinations have to be selected. The observed pronounced activation of apoptosis pathways demonstrates the decisive role of apoptosis in the loss of cell viability by BH3 mimetics.
Assuntos
Antineoplásicos , Melanoma , Pirimidinas , Tiofenos , Humanos , Melanoma/metabolismo , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2 , Proteína bcl-X/metabolismo , Apoptose , Caspases/metabolismo , Linhagem Celular Tumoral , Antineoplásicos/farmacologiaRESUMO
Mcl-1 (myeloid cell leukemia 1), a member of the Bcl-2 family, is upregulated in various types of cancer. Peptides representing the BH3 (Bcl-2 homology 3) region of pro-apoptotic proteins have been demonstrated to bind the hydrophobic groove of anti-apoptotic Mcl-1, and this interaction is responsible for regulating apoptosis. Structural studies have shown that, while there is high overall structural conservation among the anti-apoptotic Bcl-2 (B-cell lymphoma 2) proteins, differences in the surface groove of these proteins facilitates binding specificity. This binding specificity is crucial for the mechanism of action of the Bcl-2 family in regulating apoptosis. Bim-based peptides bind specifically to the hydrophobic groove of Mcl-1, emphasizing the importance of these interactions in the regulation of cell death. Molecular docking was performed with BH3-like peptides derived from Bim to identify high affinity peptides that bind to Mcl-1 and to understand the molecular mechanism of their interactions. The interactions of three identified peptides, E2gY, E2gI, and XXA1_F3dI, were further evaluated using 250 ns molecular dynamics simulations. Conserved hydrophobic residues of the peptides play an important role in their binding and the structural stability of the complexes. Understanding the molecular basis of interaction of these peptides will assist in the development of more effective Mcl-1 specific inhibitors.
Assuntos
Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Proteína de Sequência 1 de Leucemia de Células Mieloides , Peptídeos , Ligação Proteica , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Proteína de Sequência 1 de Leucemia de Células Mieloides/química , Humanos , Peptídeos/química , Peptídeos/metabolismo , Antineoplásicos/química , Antineoplásicos/farmacologia , Antineoplásicos/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Sítios de Ligação , Sequência de Aminoácidos , Proteína 11 Semelhante a Bcl-2/metabolismo , Proteína 11 Semelhante a Bcl-2/químicaRESUMO
In Multiple Myeloma (MM) the finely tuned homeostasis of the bone marrow (BM) microenvironment is disrupted. Evasion of programmed cell death (apoptosis) represents a hallmark of cancer. Besides genetic aberrations, the supportive and protective MM BM milieu, which is constituted by cytokines and growth factors, intercellular and cell: extracellular matrix (ECM) interactions and exosomes, in particular, plays a key role in the abundance of pro-survival members of the Bcl-2 family (i.e., Mcl-1, Bcl-2, and Bcl-xL) in tumor cells. Moreover, microenvironmental cues have also an impact on stability- regulating post-translational modifications of anti-apoptotic proteins including de/phosphorylation, polyubiquitination; on their intracellular binding affinities, and localization. Advances of our molecular knowledge on the escape of cancer cells from apoptosis have informed the development of a new class of small molecules that mimic the action of BH3-only proteins. Indeed, approaches to directly target anti-apoptotic Bcl-2 family members are among today's most promising therapeutic strategies and BH3-mimetics (i.e., venetoclax) are currently revolutionizing not only the treatment of CLL and AML, but also hold great therapeutic promise in MM. Furthermore, approaches that activate apoptotic pathways indirectly via modification of the tumor microenvironment have already entered clinical practice. The present review article will summarize our up-to-date knowledge on molecular mechanisms by which the MM BM microenvironment, cytokines, and growth factors in particular, mediates tumor cell evasion from apoptosis. Moreover, it will discuss some of the most promising science- derived therapeutic strategies to overcome Bcl-2- mediated tumor cell survival in order to further improve MM patient outcome.
Assuntos
Medula Óssea , Mieloma Múltiplo , Humanos , Apoptose , Proteína bcl-X/metabolismo , Medula Óssea/metabolismo , Linhagem Celular Tumoral , Citocinas/metabolismo , Mieloma Múltiplo/metabolismo , Proteína de Sequência 1 de Leucemia de Células Mieloides/química , Proteína de Sequência 1 de Leucemia de Células Mieloides/genética , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Microambiente TumoralRESUMO
Targeting BCL2 family proteins to induce cancer cell death has been successful in the treatment of cancer. BH3 mimetics such as ABT-737 not only induce cell death, but also activate autophagy. The molecular mechanism by which the BH3 mimetics induce autophagy is still controversial. In this study, we show that the BCL2/BCLXL/BCLw inhibitor navitoclax and the MCL1 inhibitor S63845 induce both apoptosis and autophagy in mouse embryonic fibroblasts (MEFs) and leukemia cell lines, while autophagy induced by navticlax and S63845 in leukemia cell lines requires the inhibition of caspase activities. Further experiments demonstrate that the autophagy induced by navitoclax or S63845 does not depend on Beclin 1, but downstream of Bax/Bak. Moreover, both navitoclax and S63845 treatment induce mtDNA release in MEFs, which activates STING and thereby induces autophagy, while STING KO inhibits both navitoclax- and S63845-induced autophagy. Furthermore, STING KO diminishes navitoclax- or S63845-induced apoptosis, suggesting that STING activation enhances rather than inhibits apoptosis. Thus, our findings provide new insights into the regulations of navitoclax- or S63845-induced autophagy and cell death.
Assuntos
Antineoplásicos , Leucemia , Animais , Camundongos , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , DNA Mitocondrial , Linhagem Celular Tumoral , Fibroblastos/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Morte Celular , Apoptose , Antineoplásicos/farmacologia , AutofagiaRESUMO
Myelodysplastic syndromes (MDSs) belong to a group of clonal bone marrow malignancies. In light of the emergence of new molecules, a significant contribution to the understanding of the pathogenesis of the disease is the study of the B-cell CLL/lymphoma 2 (BCL-2) and the programmed cell death receptor 1 (PD-1) protein and its ligands. BCL-2-family proteins are involved in the regulation of the intrinsic apoptosis pathway. Disruptions in their interactions promote the progression and resistance of MDSs. They have become an important target for specific drugs. Bone marrow cytoarchitecture may prove to be a predictor of response to its use. The challenge is the observed resistance to venetoclax, for which the MCL-1 protein may be largely responsible. Molecules with the potential to break the associated resistance include S63845, S64315, chidamide and arsenic trioxide (ATO). Despite promising in vitro studies, the role of PD-1/PD-L1 pathway inhibitors has not yet been established. Knockdown of the PD-L1 gene in preclinical studies was associated with increased levels of BCL-2 and MCL-1 in lymphocytes T, which could increase their survival and promote tumor apoptosis. A trial (NCT03969446) is currently underway to combine inhibitors from both groups.
Assuntos
Antígeno B7-H1 , Síndromes Mielodisplásicas , Receptor de Morte Celular Programada 1 , Proteínas Proto-Oncogênicas c-bcl-2 , Humanos , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Apoptose , Antígeno B7-H1/metabolismo , Linhagem Celular Tumoral , Síndromes Mielodisplásicas/tratamento farmacológico , Síndromes Mielodisplásicas/metabolismo , Proteína de Sequência 1 de Leucemia de Células Mieloides/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismoRESUMO
BACKGROUND: There are limited treatment options for ovarian cancer patients with early relapse after platinum chemotherapy. In preclinical studies, we previously demonstrated the promising activity of ABT-737, a Bcl-2/Bcl-xL anti-apoptotic protein inhibitor, in chemo-resistant ovarian cancer cells and tumors, suggesting its potential activity in platinum-resistant patients. METHODS: We conducted a prospective multicenter single-arm phase II study to assess the efficacy of Navitoclax (orally available ABT-737 analogue) monotherapy in 46 heavily pretreated (2-12 lines, median = 4) patients with high-grade serous platinum-resistant ovarian tumors. Navitoclax was administered at the daily dose of 150 mg during a lead-in period (7-14 days) and then increased to 250 mg daily in the absence of dose-limiting thrombocytopenia (Assuntos
Neoplasias Ovarianas
, Trombocitopenia
, Compostos de Anilina
, Carcinoma Epitelial do Ovário/tratamento farmacológico
, Feminino
, Humanos
, Proteína de Sequência 1 de Leucemia de Células Mieloides/uso terapêutico
, Recidiva Local de Neoplasia/patologia
, Neoplasias Ovarianas/patologia
, Platina/uso terapêutico
, Estudos Prospectivos
, Proteínas Proto-Oncogênicas c-bcl-2
, Sulfonamidas
RESUMO
Long-term, curative treatment of cutaneous T-cell lymphomas (CTCL) remains a major challenge. Therapy resistance is often based on apoptosis deficiency, and may depend on antiapoptotic Bcl-2 proteins, such as Bcl-2, Bcl-xL, Bcl-w and Mcl-1. For their targeting, several antagonists have been generated, which mimic the Bcl-2 homology domain 3 (BH3 mimetics). As dysregulation and overexpression of Mcl-1 has been reported in CTCL, the use of Mcl-1 inhibitors appears as an attractive strategy. Here, we investigated the effects of the selective Mcl-1 inhibitor S63845 in a series of four CTCL cell lines, in comparison to ABT-263 and ABT-737 (inhibitors of Bcl-2, Bcl-xL and Bcl-w). In two cell lines (HH, HuT-78), S63845 resulted in significant apoptosis induction, decrease in cell viability, loss of mitochondrial membrane potential and caspase activation, while two other cell lines (MyLa, SeAx) remained completely resistant. An inverse correlation was found, as S63845-resistant cells were highly sensitive to ABT-263/-737, and S63845-sensitive cells showed only moderate sensitivity to ABTs. Combinations of S63845 and ABT-263 partially yielded synergistic effects. As concerning Bcl-2 protein expression, weaker Mcl-1 expression was found in S63845-resistant MyLa and SeAx, while for Bcl-2 and Bcl-xL, the lowest expression was found in the highly sensitive cell line HH. The most striking difference between S63845-resistant and -sensitive cells was identified for Bcl-w, which was exclusively expressed in S63845-resistant cells. Thus, CTCL may be efficiently targeted by BH3 mimetics, providing the right target is preselected, and Bcl-w expression may serve as a suitable marker.
Assuntos
Antineoplásicos , Linfoma Cutâneo de Células T , Humanos , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteína bcl-X/metabolismo , Antineoplásicos/farmacologia , Apoptose , Caspases/metabolismo , Linfoma Cutâneo de Células T/tratamento farmacológico , Linhagem Celular TumoralRESUMO
Acute lymphoblastic leukemia (ALL) is the most common malignancy among children. Despite the enormous progress in ALL therapy, resulting in achieving a 5-year survival rate of up to 90%, the ambitious goal of reaching a 100% survival rate is still being pursued. A typical ALL treatment includes three phases: remission induction and consolidation and maintenance, preceded by a prednisone prephase. Poor prednisone response (PPR) is defined as the presence of ≥1.0 × 109 blasts/L in the peripheral blood on day eight of therapy and results in significantly frequent relapses and worse outcomes. Hence, identifying risk factors of steroid resistance and finding methods of overcoming that resistance may significantly improve patients' outcomes. A mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK-ERK) pathway seems to be a particularly attractive target, as its activation leads to steroid resistance via a phosphorylating Bcl-2-interacting mediator of cell death (BIM), which is crucial in the steroid-induced cell death. Several mutations causing activation of MAPK-ERK were discovered, notably the interleukin-7 receptor (IL-7R) pathway mutations in T-cell ALL and rat sarcoma virus (Ras) pathway mutations in precursor B-cell ALL. MAPK-ERK pathway inhibitors were demonstrated to enhance the results of dexamethasone therapy in preclinical ALL studies. This report summarizes steroids' mechanism of action, resistance to treatment, and prospects of steroids therapy in pediatric ALL.
Assuntos
Leucemia-Linfoma Linfoblástico de Células Precursoras , Leucemia-Linfoma Linfoblástico de Células T Precursoras , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Glucocorticoides/farmacologia , Glucocorticoides/uso terapêutico , Humanos , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Prednisona/uso terapêuticoRESUMO
BACKGROUND: Multi-omics studies have shown a high and lack of common driver mutations in most thymomas (TH) and thymic carcinomas (TC) that hamper the development of novel treatment approaches. However, deregulation of apoptosis has been proposed as a common hallmark of TH and TC. BH3 profiling can be utilized to study the readiness of living cancer cells to undergo apoptosis and their dependency on pro-survival BCL-2 family proteins. METHODS: We screened a cohort of 62 TH and TC patient samples for expression of BCL-2 family proteins and used the TC cell line 1889c and native TH for dynamic BH3 profiling and treatment with BH3 mimetics. RESULTS: Immunohistochemical overexpression of MCL-1 and BCL-xL was a strong prognostic marker of TH and TC, and BH3 profiling indicated a strong dependency on MCL-1 and BCL-xL in TH. Single inhibition of MCL-1 resulted in increased binding of BIM to BCL-xL as an escape mechanism that the combined inhibition of both factors could overcome. Indeed, the inhibition of MCL-1 and BCL-xL in combination induced apoptosis in a caspase-dependent manner in untreated and MCL-1-resistant 1889c cells. CONCLUSION: TH and TC are exquisitely dependent on the pro-survival factors MCL-1 and BCL-xL, making them ideal candidates for co-inhibition by BH3 mimetics. Since TH show a heterogeneous dependency on BCL-2 family proteins, upfront BH3 profiling could select patients and tailor the optimal therapy with the least possible toxicity.
Assuntos
Timoma , Neoplasias do Timo , Apoptose , Linhagem Celular Tumoral , Humanos , Proteína de Sequência 1 de Leucemia de Células Mieloides/genética , Prognóstico , Proteínas Proto-Oncogênicas c-bcl-2/genética , Neoplasias do Timo/tratamento farmacológico , Neoplasias do Timo/genética , Proteína bcl-X/genéticaRESUMO
The deregulation of apoptosis is a key contributor to tumourigenesis as it can lead to the unwanted survival of rogue cells. Drugs known as the BH3-mimetics targeting the pro-survival members of the BCL-2 protein family to induce apoptosis in cancer cells have achieved clinical success for the treatment of haematological malignancies. However, despite our increasing knowledge of the pro-survival factors mediating the unwanted survival of solid tumour cells, and our growing BH3-mimetics armamentarium, the application of BH3-mimetic therapy in solid cancers has not reached its full potential. This is mainly attributed to the need to identify clinically safe, yet effective, combination strategies to target the multiple pro-survival proteins that typically mediate the survival of solid tumours. In this review, we discuss current and exciting new developments in the field that has the potential to unleash the full power of BH3-mimetic therapy to treat currently recalcitrant solid malignancies.
Assuntos
Apoptose , Neoplasias/tratamento farmacológico , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Antineoplásicos/uso terapêutico , Linhagem Celular Tumoral , Humanos , Neoplasias/metabolismoRESUMO
The discovery of a new class of small molecule compounds that target the BCL-2 family of anti-apoptotic proteins is one of the great success stories of basic science leading to translational outcomes in the last 30 years. The eponymous BCL-2 protein was identified over 30 years ago due to its association with cancer. However, it was the unveiling of the biochemistry and structural biology behind it and its close relatives' mechanism(s)-of-action that provided the inspiration for what are now known as 'BH3-mimetics', the first clinically approved drugs designed to specifically inhibit protein-protein interactions. Herein, we chart the history of how these drugs were discovered, their evolution and application in cancer treatment.
Assuntos
Antineoplásicos/farmacologia , Sistemas de Liberação de Medicamentos , Descoberta de Drogas , Proteínas Proto-Oncogênicas c-bcl-2/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Humanos , Ligantes , Mimetismo MolecularRESUMO
The cytotoxic effect of anti-cancer drugs relies on their ability to induce programmed cell death known as apoptosis. Evading apoptosis is a common characteristic of cancer cells and it is linked to both carcinogenesis and anticancer drug resistance. To escape apoptosis, cancer cells often express high levels of anti-apoptotic proteins and become "addicted "to them for their survival. Consequently, anti-apoptotic proteins have emerged as attractive druggable targets for the development of cancer therapeutics. In this review we focus on two major anti-apoptotic protein families: IAPs (Inhibitor of Apoptosis) proteins and Bcl-2 (B-cell lymphoma-2) family members. We also discuss insights into the regulation of these proteins by natural antagonists, which has provided the conceptual basis for developing novel anti-cancer drugs. Significantly, the pro-apoptotic protein ARTS (apoptosis-related protein in the TGF-ß signaling pathway; Sept4_i2) acts as a dual antagonist of both X-linked inhibitor of apoptosis protein (XIAP) and Bcl-2. Because upregulation of anti-apoptotic proteins in response to cancer therapy contributes to drug resistance, targeted inhibition of these proteins is expected to enhance the efficacy of chemotherapy. Finally, we discuss the role of proteasome-mediated degradation in the regulation of apoptosis, and how this mechanism can be harnessed to develop small molecules that stimulate degradation of anti-apoptotic proteins for cancer therapy. This strategy has the potential to overcome drug resistance more effectively than mere inhibition. Therefore, this approach may allow use of lower drug concentrations and thereby reduce cytotoxicity and untoward side effects.
Assuntos
Antineoplásicos/farmacologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Proteínas Inibidoras de Apoptose/metabolismo , Neoplasias/tratamento farmacológico , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Proteínas Inibidoras de Apoptose/antagonistas & inibidores , Terapia de Alvo Molecular/métodos , Neoplasias/patologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteólise/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Regulação para Cima/efeitos dos fármacosRESUMO
Aplysinopsins are a class of marine indole alkaloids that exhibit a wide range of biological activities. Although both the indole and N-benzyl moieties of aplysinopsins are known to possess antiproliferative activity against cancer cells, their mechanism of action remains unclear. Through in vitro and in vivo proliferation and viability screening of newly synthesized aplysinopsin analogs on myelogenous leukemia cell lines and zebrafish toxicity tests, as well as analysis of differential toxicity in noncancerous RPMI 1788 cells and PBMCs, we identified EE-84 as a promising novel drug candidate against chronic myeloid leukemia. This indole derivative demonstrated drug-likeness in agreement with Lipinski's rule of five. Furthermore, EE-84 induced a senescent-like phenotype in K562 cells in line with its cytostatic effect. EE-84-treated K562 cells underwent morphological changes in line with mitochondrial dysfunction concomitant with autophagy and ER stress induction. Finally, we demonstrated the synergistic cytotoxic effect of EE-84 with a BH3 mimetic, the Mcl-1 inhibitor A-1210477, against imatinib-sensitive and resistant K562 cells, highlighting the inhibition of antiapoptotic Bcl-2 proteins as a promising novel senolytic approach against chronic myeloid leukemia.
Assuntos
Antineoplásicos/farmacologia , Citotoxinas/farmacologia , Indóis/farmacologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Sulfonamidas/farmacologia , Triptofano/análogos & derivados , Animais , Antineoplásicos/química , Antineoplásicos/toxicidade , Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Linhagem Celular , Citotoxinas/química , Citotoxinas/toxicidade , Sinergismo Farmacológico , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Humanos , Indóis/química , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Proteína de Sequência 1 de Leucemia de Células Mieloides/antagonistas & inibidores , Sulfonamidas/química , Triptofano/química , Triptofano/farmacologia , Triptofano/toxicidade , Peixe-ZebraRESUMO
Hematologic malignancies (HM) comprise diverse cancers of lymphoid and myeloid origin, including lymphomas (approx. 40%), chronic lymphocytic leukemia (CLL, approx. 15%), multiple myeloma (MM, approx. 15%), acute myeloid leukemia (AML, approx. 10%), and many other diseases. Despite considerable improvement in treatment options and survival parameters in the new millennium, many patients with HM still develop chemotherapyrefractory diseases and require re-treatment. Because frontline therapies for the majority of HM (except for CLL) are still largely based on classical cytostatics, the relapses are often associated with defects in DNA damage response (DDR) pathways and anti-apoptotic blocks exemplified, respectively, by mutations or deletion of the TP53 tumor suppressor, and overexpression of anti-apoptotic proteins of the B-cell lymphoma 2 (BCL2) family. BCL2 homology 3 (BH3) mimetics represent a novel class of pro-apoptotic anti-cancer agents with a unique mode of action-direct targeting of mitochondria independently of TP53 gene aberrations. Consequently, BH3 mimetics can effectively eliminate even non-dividing malignant cells with adverse molecular cytogenetic alterations. Venetoclax, the nanomolar inhibitor of BCL2 anti-apoptotic protein has been approved for the therapy of CLL and AML. Numerous venetoclax-based combinatorial treatment regimens, next-generation BCL2 inhibitors, and myeloid cell leukemia 1 (MCL1) protein inhibitors, which are another class of BH3 mimetics with promising preclinical results, are currently being tested in several clinical trials in patients with diverse HM. These pivotal trials will soon answer critical questions and concerns about these innovative agents regarding not only their anti-tumor efficacy but also potential side effects, recommended dosages, and the optimal length of therapy as well as identification of reliable biomarkers of sensitivity or resistance. Effective harnessing of the full therapeutic potential of BH3 mimetics is a critical mission as it may directly translate into better management of the aggressive forms of HM and could lead to significantly improved survival parameters and quality of life in patients with urgent medical needs.
Assuntos
Neoplasias Hematológicas/tratamento farmacológico , Neoplasias Hematológicas/metabolismo , Animais , Apoptose/fisiologia , Biomarcadores/metabolismo , Compostos Bicíclicos Heterocíclicos com Pontes/uso terapêutico , Dano ao DNA/efeitos dos fármacos , Dano ao DNA/genética , Humanos , Sulfonamidas/uso terapêutico , Proteína Supressora de Tumor p53/metabolismoRESUMO
Colorectal cancer (CRC) is a heterogeneous disease, which in part explains the differential response to chemotherapy observed in the clinic. BH3 mimetics, which target anti-apoptotic BCL-2 family members, have shown potential in the treatment of hematological malignancies and offer promise for the treatment of solid tumors as well. To gain a comprehensive understanding of the response to BH3 mimetics in CRC and the underlying molecular factors predicting sensitivity, we screened a panel of CRC cell lines with four BH3 mimetics targeting distinct anti-apoptotic BCL-2 proteins. Treatment with compounds alone and in combination revealed potent efficacy of combined MCL-1 and BCL-XL inhibition in inducing CRC cell death, irrespective of molecular features. Importantly, expression of the anti-apoptotic protein target of BH3 mimetics on its own did not predict sensitivity. However, the analysis did identify consensus molecular subtype (CMS) specific response patterns, such as higher resistance to single and combined BCL-2 and MCL-1 inhibition in CMS2 cell lines. Furthermore, analysis of mutation status revealed that KRAS mutant cell lines were more resistant to MCL-1 inhibition. Conclusively, we find that CRC cell lines presented with distinct responses to BH3 mimetics that can in part be predicted by their CMS profile and KRAS/BRAF mutations. Overall, almost all CRC lines share sensitivity in the nanomolar range to combined MCL-1 and BCL-XL targeting suggesting that this would be the preferred approach to target these cancers.
Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/química , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/farmacologia , Biomimética , Mimetismo Molecular , Apoptose/efeitos dos fármacos , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Neoplasias Colorretais , Relação Dose-Resposta a Droga , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas p21(ras)/genéticaRESUMO
Cancer is one of the main causes of death worldwide, and, among the most frequent cancer types, osteosarcoma accounts for 56% of bone neoplasms observed in children and colorectal cancer for 10.2% of tumors diagnosed in the adult population. A common and frequent hurdle in cancer treatment is the emergence of resistance to chemo- and radiotherapy whose biological causes are largely unknown. In the present work, human osteosarcoma (SAOS) and colorectal adenocarcinoma (HT29) cell lines were γ-irradiated at doses mimicking the sub-lethal irradiation in clinical settings to obtain two radio-resistant cellular sub-populations named SAOS400 and HT500, respectively. Since "therapy-induced senescence" (TIS) is often associated with tumor response to radiotherapy in cancer cells, we measured specific cellular and biochemical markers of senescence in SAOS400 and HT500 cells. In detail, both cell lines were characterized by a higher level of expression of cyclin-dependent kinase inhibitors p16INK4 and p21CIP1 and increased positivity to SAß-gal (senescence-associated ß-galactosidase) with respect to parental cells. Moreover, the intracellular levels of reactive oxygen species in the resistant cells were significantly lower compared to the parental counterparts. Subsequently, we demonstrated that senolytic agents were able to sensitize SAOS400 and HT500 to cell death induced by γ-irradiation. Employing two natural flavonoids, fisetin and quercetin, and a BH3-mimetic, ABT-263/navitoclax, we observed that their association with γ-irradiation significantly reduced the expression of p16INK4, p21CIP1 and synergistically (combination index < 1) increased cell death compared to radiation mono-alone treatments. The present results reinforce the potential role of senolytics as adjuvant agents in cancer therapy.