Akt targeting as a strategy to boost chemotherapy efficacy in non-small cell lung cancer through metabolism suppression

Novel therapeutic approaches for non-small cell lung cancer: an updated view

Non-small cell lung cancer (NSCLC) continues to be one of the leading causes of cancer-related mortality globally. Most patients who undergo surgical procedures may encounter distant metastasis or local recurrence, necessitating supplementary treatments such as radiation therapy, chemotherapy, or targeted therapy as adjuvant alternatives. Recent advancements in molecular biology and immunotherapy have paved the way for innovative therapeutic approaches that target specific genetic mutations and promote the immune response against tumour cells. This review explores emerging therapies, including targeted therapies such as tyrosine kinase inhibitors (TKIs) for actionable mutations (e.g., EGFR, ALK, ROS1), as well as the role of immune checkpoint inhibitors (ICIs) that employ the body's immune system to combat cancer. Additionally, we discuss the potential of exosome therapies, as well as promising nanotherapeutic options for the treatment of NSCLC. This study attempts to provide a thorough overview of the changing landscape of NSCLC treatment and its implications for enhancing patient outcomes by presenting these innovative techniques.

MAT1A activation of glycolysis to promote NSCLC progression depends on stabilizing CCND1

Non-small cell lung cancer (NSCLC) remains a cause for concern as the leading cause of cancer-related death worldwide. Amidst ongoing debates on the role and mechanisms of methionine adenosyltransferase 1A (MAT1A) in cancer, our study sheds light on its significance in NSCLC. Leveraging TCGA database and immunohistochemical staining, we systematically analyzed MAT1A expression in NSCLC, uncovering its marked upregulation. To unravel the functional and mechanistic underpinnings, we implemented stable knockdown of MAT1A in NSCLC cell lines. Our findings converged to demonstrate that suppression of MAT1A expression effectively impeded the proliferation and migratory capabilities of NSCLC cells, while concurrently enhancing apoptosis. Mechanistically, we discovered that MAT1A depletion accelerated the degradation of CCND1, a key cell cycle regulator, through S-phase kinase-associated protein 2 (SKP2)-mediated ubiquitination. Notably, CCND1 emerged as a crucial MAT1A partner, jointly orchestrating glycolytic metabolism in NSCLC cells. This intricate interplay suggests that MAT1A promotes NSCLC progression by safeguarding CCND1 protein stability and activating glycolytic pathways, thereby sustaining tumorigenesis. In summary, our study not only identifies MAT1A as a prognostic marker for poor survival in NSCLC patients but also elucidates its mechanistic contributions to cancer progression. These findings pave the way for the development of targeted therapies aimed at disrupting the deleterious MAT1A-CCND1-glycolysis axis in NSCLC.

CAVPENET Peptide Inhibits Prostate Cancer Cells Proliferation and Migration through PP1γ-Dependent Inhibition of AKT Signaling

Protein phosphatase 1 (PP1) complexes have emerged as promising targets for anticancer therapies. The ability of peptides to mimic PP1-docking motifs, and so modulate interactions with regulatory factors, has enabled the creation of highly selective modulators of PP1-dependent cellular processes that promote tumor growth. The major objective of this study was to develop a novel bioactive cell-penetrating peptide (bioportide), which, by mimicking the PP1-binding motif of caveolin-1 (CAV1), would regulate PP1 activity, to hinder prostate cancer (PCa) progression. The designed bioportide, herein designated CAVPENET, and a scrambled homologue, were synthesized using microwave-assisted solid-phase methodologies and evaluated using PCa cell lines. Our findings indicate that CAVPENET successfully entered PCa cells to influence both viability and migration. This tumor suppressor activity of CAVPENET was attributed to inhibition of AKT signaling, a consequence of increased PP1γ activity. This led to the suppression of glycolytic metabolism and alteration in lipid metabolism, collectively representing the primary mechanism responsible for the anticancer properties of CAVPENET. Our results underscore the potential of the designed peptide as a novel therapy for PCa patients, setting the stage for further testing in more advanced models to fully realize its therapeutic promise.

Augmented drug combination dataset to improve the performance of machine learning models predicting synergistic anticancer effects

Combination therapy has gained popularity in cancer treatment as it enhances the treatment efficacy and overcomes drug resistance. Although machine learning (ML) techniques have become an indispensable tool for discovering new drug combinations, the data on drug combination therapy currently available may be insufficient to build high-precision models. We developed a data augmentation protocol to unbiasedly scale up the existing anti-cancer drug synergy dataset. Using a new drug similarity metric, we augmented the synergy data by substituting a compound in a drug combination instance with another molecule that exhibits highly similar pharmacological effects. Using this protocol, we were able to upscale the AZ-DREAM Challenges dataset from 8798 to 6,016,697 drug combinations. Comprehensive performance evaluations show that ML models trained on the augmented data consistently achieve higher accuracy than those trained solely on the original dataset. Our data augmentation protocol provides a systematic and unbiased approach to generating more diverse and larger-scale drug combination datasets, enabling the development of more precise and effective ML models. The protocol presented in this study could serve as a foundation for future research aimed at discovering novel and effective drug combinations for cancer treatment.

Augmented drug combination dataset to improve the performance of machine learning models predicting synergistic anticancer effects

Combination therapy has gained popularity in cancer treatment as it enhances the treatment efficacy and overcomes drug resistance. Although machine learning (ML) techniques have become an indispensable tool for discovering new drug combinations, the data on drug combination therapy currently available may be insufficient to build high-precision models. We developed a data augmentation protocol to unbiasedly scale up the existing anti-cancer drug synergy dataset. Using a new drug similarity metric, we augmented the synergy data by substituting a compound in a drug combination instance with another molecule that exhibits highly similar pharmacological effects. Using this protocol, we were able to upscale the AZ-DREAM Challenges dataset from 8,798 to 6,016,697 drug combinations. Comprehensive performance evaluations show that Random Forest and Gradient Boosting Trees models trained on the augmented data achieve higher accuracy than those trained solely on the original dataset. Our data augmentation protocol provides a systematic and unbiased approach to generating more diverse and larger-scale drug combination datasets, enabling the development of more precise and effective ML models. The protocol presented in this study could serve as a foundation for future research aimed at discovering novel and effective drug combinations for cancer treatment.

Recent advances in non-small cell lung cancer targeted therapy; an update review

Lung cancer continues to be the leading cause of cancer-related death worldwide. In the last decade, significant advancements in the diagnosis and treatment of lung cancer, particularly NSCLC, have been achieved with the help of molecular translational research. Among the hopeful breakthroughs in therapeutic approaches, advances in targeted therapy have brought the most successful outcomes in NSCLC treatment. In targeted therapy, antagonists target the specific genes, proteins, or the microenvironment of tumors supporting cancer growth and survival. Indeed, cancer can be managed by blocking the target genes related to tumor cell progression without causing noticeable damage to normal cells. Currently, efforts have been focused on improving the targeted therapy aspects regarding the encouraging outcomes in cancer treatment and the quality of life of patients. Treatment with targeted therapy for NSCLC is changing rapidly due to the pace of scientific research. Accordingly, this updated study aimed to discuss the tumor target antigens comprehensively and targeted therapy-related agents in NSCLC. The current study also summarized the available clinical trial studies for NSCLC patients.

Targeting glycolysis in non-small cell lung cancer: Promises and challenges

Metabolic disturbance, particularly of glucose metabolism, is a hallmark of tumors such as non-small cell lung cancer (NSCLC). Cancer cells tend to reprogram a majority of glucose metabolism reactions into glycolysis, even in oxygen-rich environments. Although glycolysis is not an efficient means of ATP production compared to oxidative phosphorylation, the inhibition of tumor glycolysis directly impedes cell survival and growth. This review focuses on research advances in glycolysis in NSCLC and systematically provides an overview of the key enzymes, biomarkers, non-coding RNAs, and signaling pathways that modulate the glycolysis process and, consequently, tumor growth and metastasis in NSCLC. Current medications, therapeutic approaches, and natural products that affect glycolysis in NSCLC are also summarized. We found that the identification of appropriate targets and biomarkers in glycolysis, specifically for NSCLC treatment, is still a challenge at present. However, LDHB, PDK1, MCT2, GLUT1, and PFKM might be promising targets in the treatment of NSCLC or its specific subtypes, and DPPA4, NQO1, GAPDH/MT-CO1, PGC-1α, OTUB2, ISLR, Barx2, OTUB2, and RFP180 might be prognostic predictors of NSCLC. In addition, natural products may serve as promising therapeutic approaches targeting multiple steps in glycolysis metabolism, since natural products always present multi-target properties. The development of metabolic intervention that targets glycolysis, alone or in combination with current therapy, is a potential therapeutic approach in NSCLC treatment. The aim of this review is to describe research patterns and interests concerning the metabolic treatment of NSCLC.

Research progress on the interaction between long non‑coding RNAs and RNA‑binding proteins to influence the reprogramming of tumor glucose metabolism (Review)

As epigenetic regulators, long non-coding RNAs (lncRNAs) are involved in various important regulatory processes and typically interact with RNA-binding proteins (RBPs) to exert their core functional effects. An increasing number of studies have demonstrated that lncRNAs can regulate the occurrence and development of cancer through a variety of complex mechanisms and can also participate in tumor glucose metabolism by directly or indirectly regulating the Warburg effect. As one of the metabolic characteristics of tumor cells, the Warburg effect provides a large amount of energy and numerous intermediate products to meet the consumption demands of tumor metabolism, providing advantages for the occurrence and development of tumors. The present review article summarizes the regulatory effects of lncRNAs on the reprogramming of glucose metabolism after interacting with RBPs in tumors. The findings discussed herein may aid in the better understanding of the pathogenesis of malignancies, and may provide novel therapeutic targets, as well as new diagnostic and prognostic markers for human cancers.

Regulation of Metabolism by Mitochondrial MUL1 E3 Ubiquitin Ligase

MUL1 is a multifunctional E3 ubiquitin ligase that is involved in various pathophysiological processes including apoptosis, mitophagy, mitochondrial dynamics, and innate immune response. We uncovered a new function for MUL1 in the regulation of mitochondrial metabolism. We characterized the metabolic phenotype of MUL1(-/-) cells using metabolomic, lipidomic, gene expression profiling, metabolic flux, and mitochondrial respiration analyses. In addition, the mechanism by which MUL1 regulates metabolism was investigated, and the transcription factor HIF-1α, as well as the serine/threonine kinase Akt2, were identified as the mediators of the MUL1 function. MUL1 ligase, through K48-specific polyubiquitination, regulates both Akt2 and HIF-1α protein level, and the absence of MUL1 leads to the accumulation and activation of both substrates. We used specific chemical inhibitors and activators of HIF-1α and Akt2 proteins, as well as Akt2(-/-) cells, to investigate the individual contribution of HIF-1α and Akt2 proteins to the MUL1-specific phenotype. This study describes a new function of MUL1 in the regulation of mitochondrial metabolism and reveals how its downregulation/inactivation can affect mitochondrial respiration and cause a shift to a new metabolic and lipidomic state.

Metronomic Chemotherapy Modulates Clonal Interactions to Prevent Drug Resistance in Non-Small Cell Lung Cancer

Despite recent advances in deciphering cancer drug resistance mechanisms, relapse is a widely observed phenomenon in advanced cancers, mainly due to intratumor clonal heterogeneity. How tumor clones progress and impact each other remains elusive. In this study, we developed 2D and 3D non-small cell lung cancer co-culture systems and defined a phenomenological mathematical model to better understand clone dynamics. Our results demonstrated that the drug-sensitive clones inhibit the proliferation of the drug-resistant ones under untreated conditions. Model predictions and their experimental in vitro and in vivo validations indicated that a metronomic schedule leads to a better regulation of tumor cell heterogeneity over time than a maximum-tolerated dose schedule, while achieving control of tumor progression. We finally showed that drug-sensitive and -resistant clones exhibited different metabolic statuses that could be involved in controlling the intratumor heterogeneity dynamics. Our data suggested that the glycolytic activity of drug-sensitive clones could play a major role in inhibiting the drug-resistant clone proliferation. Altogether, these computational and experimental approaches provide foundations for using metronomic therapy to control drug-sensitive and -resistant clone balance and highlight the potential of targeting cell metabolism to manage intratumor heterogeneity.

Mitochondrial spare respiratory capacity: Mechanisms, regulation, and significance in non-transformed and cancer cells

Mitochondrial metabolism must constantly adapt to stress conditions in order to maintain bioenergetic levels related to cellular functions. This absence of proper adaptation can be seen in a wide array of conditions, including cancer. Metabolic adaptation calls on mitochondrial function and draws on the mitochondrial reserve to meet increasing needs. Among mitochondrial respiratory parameters, the spare respiratory capacity (SRC) represents a particularly robust functional parameter to evaluate mitochondrial reserve. We provide an overview of potential SRC mechanisms and regulation with a focus on its particular significance in cancer cells.

Randomized, placebo-controlled, phase 3 study of perifosine combined with bortezomib and dexamethasone in patients with relapsed, refractory multiple myeloma previously treated with bortezomib

Perifosine, an investigational, oral, synthetic alkylphospholipid, inhibits signal transduction pathways of relevance in multiple myeloma (MM) including PI3K/Akt. Perifosine demonstrated anti-MM activity in preclinical studies and encouraging early-phase clinical activity in combination with bortezomib. A randomized, double-blind, placebo-controlled phase 3 study was conducted to evaluate addition of perifosine to bortezomib-dexamethasone in MM patients with one to four prior therapies who had relapsed following previous bortezomib-based therapy. The primary endpoint was progression-free survival (PFS). The study was discontinued at planned interim analysis, with 135 patients enrolled. Median PFS was 22.7 weeks (95% confidence interval 16·0-45·4) in the perifosine arm and 39.0 weeks (18.3-50.1) in the placebo arm (hazard ratio 1.269 [0.817-1.969]; P = .287); overall response rates were 20% and 27%, respectively. Conversely, median overall survival (OS) was 141.9 weeks and 83.3 weeks (hazard ratio 0.734 [0.380-1.419]; P = .356). Overall, 61% and 55% of patients in the perifosine and placebo arms reported grade 3/4 adverse events, including thrombocytopenia (26% vs 14%), anemia (7% vs 8%), hyponatremia (6% vs 8%), and pneumonia (9% vs 3%). These findings demonstrate no PFS benefit from the addition of perifosine to bortezomib-dexamethasone in this study of relapsed/refractory MM, but comparable safety and OS.

Metronomic chemotherapy for patients with metastatic breast cancer: Review of effectiveness and potential use during pandemics

Metronomic chemotherapy (M-CT) is defined as dose dense administration of chemotherapy at lower doses than maximum tolerated dose but at shorter free intervals, to obtain a near continuous exposure of cancer cells to those potentially effective drugs. M-CT is a useful strategy to obtain response, overcome resistance and reduce side effects, with low costs. This review will focus on the use of M-CT in advanced breast cancer (ABC). Cytostatic and cytotoxic effect on cancer cells, the anti-angiogenic and the immunomodulatory effects are its main mechanisms of actions. Many clinical trials proved the efficacy and tolerability of different monotherapies and combinations of chemotherapeutic agents administered in metronomic doses and frequencies in ABC. M-CT is a reasonable option for second and later lines of chemotherapy in metastatic breast cancer including those with prior anthracycline or taxane exposure, older patients and patients with comorbidities, and even as first-line in certain groups of patients. The acceptable efficacy and low toxicity of oral metronomic chemotherapy makes it a reasonable option during COVID-19 pandemic as well as in the post-COVID era which is projected to last for some time.

Chemical modifications of imidazole-containing alkoxyamines increase C-ON bond homolysis rate: Effects on their cytotoxic properties in glioblastoma cells

Previously, we described alkoxyamines bearing a pyridine ring as new pro-drugs with low molecular weights and theranostic activity. Upon chemical stimulus, alkoxyamines undergo homolysis and release free radicals, which can, reportedly, enhance magnetic resonance imaging and trigger cancer cell death. In the present study, we describe the synthesis and the anti-cancer activity of sixteen novel alkoxyamines that contain an imidazole ring. Activation of the homolysis was conducted by protonation and/or methylation. These new molecules displayed cytotoxic activities towards human glioblastoma cell lines, including the U251-MG cells that are highly resistant to the conventional chemotherapeutic agent Temozolomide. We further showed that the biological activities of the alkoxyamines were not only related to their half-life times of homolysis. We lastly identified the alkoxyamine (RS/SR)-4a, with both a high antitumour activity and favourable logD_7.4 and pK_a values, which make it a robust candidate for blood-brain barrier penetrating therapeutics against brain neoplasia.

Quantitative ubiquitylome analysis and crosstalk with proteome/acetylome analysis identified novel pathways and targets of perifosine treatment in neuroblastoma

BACKGROUND

Perifosine, is a third generation alkylphospholipid analog which has promising anti-tumor efficacy in clinical trials of refractory/recurrent neuroblastoma (NB). However, perifosine's mechanism of action remains unclear. Previously, we have shown that perifosine changes global proteome and acetylome profiles in NB.

METHODS

To obtain a more comprehensive understanding of the perifosine mechanism, we performed a quantitative assessment of the lysine ubiquitylome in SK-N-AS NB cells using SILAC labeling, affinity enrichment and high-resolution liquid chromatography combined with mass spectrometry analysis. To analyse the data of ubiquitylome, we performed enrichment analysis with gene ontology (GO), the Encyclopedia of Genes and Genomes (KEGG) pathway, ubiquitylated lysine motif, protein complex and protein domain. Protein-protein interaction was conducted to explore the crosstalk between ubiquitylome and previous global proteome/acetylome. Co-immunoprecipitation and western blotting were used to validate the results of the ubiquitylome analysis.

RESULTS

Altogether, 3,935 sites and 1,658 proteins were quantified. These quantified ubiquitylated proteins participated in various cellular processes such as binding, catalytic activity, biological regulation, metabolic process and signaling pathways involving non-homologous end-joining, steroid biosynthesis and Ras signaling pathway. Ubiquitylome and proteome presented negative connection. We identified 607 sites which were modified with both ubiquitination and acetylation. We selected 14 proteins carrying differentially quantified lysine ubiquitination and acetylation sites at the threshold of 1.5 folds as potential targets. These proteins were enriched in activities associated with ribosome, cell cycle and metabolism.

CONCLUSIONS

Our study extends our understanding of the spectrum of novel targets that are differentially ubiquitinated after perifosine treatment of NB tumor cells.

SOX2, a stemness gene, induces progression of NSCLC A549 cells toward anchorage-independent growth and chemoresistance to vinblastine

Background

Non-small cell lung cancer (NSCLC) is difficult to treat successfully. This intractability is mainly due to the cancer progressing through invasion, metastasis, chemotherapeutic resistance and relapse. Stemness has been linked to the various steps of cancer progression in a variety of tumors, yet little is known regarding its role in NSCLC.

Purpose

In this study, we sought to determine the role of SOX2, a master regulator of pluripotency, in the growth of extracellular matrix (ECM)-detached cells during cancer progression.

Methods

We established a three-dimensional (3D) Poly-2-hydroxyethyl methacrylate (poly-HEMA) culture of lung adenocarcinoma (LUAD) A549 cells as an ECM-detached cell growth model and examined the role of stemness genes using siRNA and small molecule inhibitor in comparison to standard two dimensional (2D) culture.

Results

In poly-HEMA culture, A549 cells formed substratum-detached spheroids with characteristics of intermediate epithelial to mesenchymal transition (EMT) and exhibited greater expression of SOX2 than did control 2D cells. Knockdown of SOX2 markedly suppressed the growth of A549 cell aggregates in poly-HEMA culture conditions and furthermore increased their sensitivity to the anticancer drug vinblastine with concomitant downregulation of the activity of the anti-apoptotic AKT kinase. Interestingly, a small molecule, RepSox, which replaces SOX2, stimulated A549 cell growth in poly-HEMA 3D culture condition.

Conclusion

Our findings strongly indicate that SOX2 contributes to anchorage-independent growth and chemoresistance via its downstream signaling mediator AKT kinase during the disease progression of NSCLC. SOX2 may therefore be an invaluable therapeutic target of NSCLC.

A cytoplasmic long noncoding RNA LINC00470 as a new AKT activator to mediate glioblastoma cell autophagy

BACKGROUND

Despite the overwhelming number of investigations on AKT, little is known about lncRNA on AKT regulation, especially in GBM cells.

METHODS

RNA-binding protein immunoprecipitation assay (RIP) and RNA pulldown were used to confirm the binding of LINC00470 and fused in sarcoma (FUS). Confocal imaging, co-immunoprecipitation (Co-IP) and GST pulldown assays were used to detect the interaction between FUS and AKT. EdU assay, CCK-8 assay, and intracranial xenograft assays were performed to demonstrate the effect of LINC00470 on the malignant phenotype of GBM cells. RT-qPCR and Western blotting were performed to test the effect of LINC00470 on AKT and pAKT.

RESULTS

In this study, we demonstrated that LINC00470 was a positive regulator for AKT activation in GBM. LINC00470 bound to FUS and AKT to form a ternary complex, anchoring FUS in the cytoplasm to increase AKT activity. Higher pAKT activated by LINC00470 inhibited ubiquitination of HK1, which affected glycolysis, and inhibited cell autophagy. Furthermore, higher LINC00470 expression was associated with GBM tumorigenesis and poor patient prognosis.

CONCLUSIONS

Our findings revealed a noncanonical AKT activation signaling pathway, i.e., LINC00470 directly interacts with FUS, serving as an AKT activator to promote GBM progression. LINC00470 has an important referential significance to evaluate the prognosis of patients.

LncRNA ATB promotes proliferation and metastasis in A549 cells by down-regulation of microRNA-494

Lung cancer is a commonly diagnosed disease with poor prognosis. Novel therapeutic targets and deep understanding of the regulatory mechanisms in lung cancer are of great importance. We aimed to figure out the functional roles of lncRNA-activated by transforming growth factor-β (ATB) in A549 cells as well as the underlying molecular mechanisms. ATB was non-physiologically expressed in A549 cells after cell transfection. Then, cell proliferation, expressions of proteins related to proliferation and epithelial-mesenchymal transition (EMT), migration, and invasion were measured by BrdU incorporation assay, Western blot analysis, and Transwell assay, respectively. Afterwards, miR-494 expression in transfected A549 cells was determined by quantitative reverse transcription PCR. Meanwhile, effects of miR-494 overexpression on ATB-overexpressed cells were assessed. Finally, the phosphorylation levels of AKT and key kinases in the Janus-activated kinase (JAK)/signal transducer and activator of transcription-3 (STAT3) pathway were detected by Western blot analysis. ATB overexpression promoted proliferation, migration, and invasion of A549 cells. Meanwhile, EMT of A549 cells was also enhanced. ATB silence showed the opposite influence. Expression of miR-494 was negatively regulated by ATB. Following experiments showed ATB-induced alterations of proliferation, migration, invasion, and EMT were all reversed by miR-494 overexpression. Finally, we proved that ATB increased phosphorylated levels of AKT, JAK1, and STAT3, and those increases were all reversed by miR-494 overexpression. We interestingly figured out that ATB promoted proliferation, migration, invasion, and EMT through down-regulating miR-494 in A549 cells. Moreover, ATB might activate AKT and the JAK/STAT3 pathway via down-regulating miR-494.

Mitochondrial Inhibition Augments the Efficacy of Imatinib by Resetting the Metabolic Phenotype of Gastrointestinal Stromal Tumor

Purpose: Imatinib dramatically reduces gastrointestinal stromal tumor (GIST) ¹⁸F-FDG uptake, providing an early indicator of treatment response. Despite decreased glucose internalization, many GIST cells persist, suggesting that alternative metabolic pathways are used for survival. The role of mitochondria in imatinib-treated GIST is largely unknown.Experimental Design: We quantified the metabolic activity of several human GIST cell lines. We treated human GIST xenografts and genetically engineered Kit^V558del/+ mice with the mitochondrial oxidative phosphorylation inhibitor VLX600 in combination with imatinib and analyzed tumor volume, weight, histology, molecular signaling, and cell cycle activity. In vitro assays on human GIST cell lines were also performed.Results: Imatinib therapy decreased glucose uptake and downstream glycolytic activity in GIST-T1 and HG129 cells by approximately half and upregulated mitochondrial enzymes and improved mitochondrial respiratory capacity. Mitochondrial inhibition with VLX600 had a direct antitumor effect in vitro while appearing to promote glycolysis through increased AKT signaling and glucose transporter expression. When combined with imatinib, VLX600 prevented imatinib-induced cell cycle escape and reduced p27 expression, leading to increased apoptosis when compared to imatinib alone. In Kit^V558del/+ mice, VLX600 alone did not induce tumor cell death, but had a profound antitumor effect when combined with imatinib.Conclusions: Our findings show that imatinib alters the metabolic phenotype of GIST, and this may contribute to imatinib resistance. Our work offers preclinical proof of concept of metabolic targeting as an effective strategy for the treatment of GIST. Clin Cancer Res; 24(4); 972-84. ©2017 AACR.