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RAS mutations are prevalent in leukemia, including mutations at G12, G13, T58, Q61, K117, and A146. These mutations are often crucial for tumor initiation, maintenance, and recurrence. While much is known about RAS function in the last 40 years, there is a substantial knowledge gap concerning the mutation-specific biological activities of RAS in cancer and the approaches needed to target specific RAS mutants effectively. The recent approval of KRASG12C inhibitors, adagrasib and sotorasib, has validated KRAS as a direct therapeutic target and demonstrated the feasibility of selectively targeting specific RAS mutants. Nevertheless, KRASG12C remains the only RAS mutant successfully targeted with FDA approved inhibitors for cancer treatment in patients, limiting its applicability for other oncogenic RAS mutants, such as G12D in leukemia. Despite these challenges, new approaches have generated optimism about targeting specific RAS mutations in an allele-dependent manner for cancer therapy, supporting by compelling biochemical and structural evidence, which inspires further exploration of RAS allele-specific vulnerabilities. This review will discuss recent advances and challenges in the development of therapies targeting RAS signaling, highlight emerging therapeutic strategies, and emphasize the importance of allele-specific approaches for leukemia treatment.

RAS clustering at the cell membrane is critical to activate signaling in cells, but whether this clustering is mediated exclusively by its c-terminal hypervariable region, receives contributions from the G-domain of RAS, and/or is influenced by secondary effectors has been intensely debated. Reports that G-domain mutations do not modulate RAS-RAS interactions have led some to question the validity of previous experiments that indicate the G-domain plays a role in RAS clustering/interactions. Here we reconcile these findings by clarifying the impact of experimental variables, such as protein expression levels, cellular context, RAS zygosity, and secondary effector interactions on RAS clustering. Lack of control over these variables impacts the results using G-domain mutations across various assay systems and can lead to unsound conclusions., Competing Interests: Conflict of interests The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: K.D.W is a member of the SAB and equity holder in Velorum Therapeutics. Additionally, K.D.W has served on advisory boards or provided professional services for Sanofi, Amgen, Reactive Biosciences, AstraZeneca and Vibliome Therapeutics., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: Consolidative durvalumab, an anti-programmed death ligand 1 (PDL1) immune checkpoint inhibitor, administered after concurrent chemoradiation improves outcomes of patients with locally advanced non-small cell lung cancer (NSCLC) without substantially increasing toxicities. We studied a chemotherapy-free regimen of thoracic radiation therapy (RT) with concurrent and consolidative durvalumab., Methods and Materials: This single-arm phase 2 trial enrolled patients with stage III NSCLC (regardless of tumor PDL1 expression), Eastern Cooperative Oncology Group (ECOG) performance status 0-1, adequate pulmonary function, and RT fields meeting standard organ constraints. Participants received 2 cycles of durvalumab (1500 mg every 4 weeks) concurrently with thoracic RT (60 Gy in 30 fractions), followed by up to 13 cycles of consolidative durvalumab., Results: After 10 patients were enrolled, the trial was closed because of poor clinical outcomes. With a median follow-up of 12 months, 5 patients had disease progression and 8 patients died. Six patients experienced 15 treatment-related, grade ≥3 events, including 1 grade 4 acute kidney injury during consolidation and 2 fatal pulmonary events. One fatal pulmonary event occurred during the concurrent phase in an active smoker; the other occurred after the first cycle of consolidative durvalumab. The primary endpoint of progression-free survival at 12 months was 20% (50% for PDL1≥1% vs 0% for PDL1 unavailable or <1%). Median overall survival was not reached, 10.5 months, and 7 months, for PDL1 ≥1%, <1%, and unavailable, respectively., Conclusions: In PDL1 unselected stage III NSCLC, thoracic RT plus concurrent and consolidative durvalumab is associated with high-grade toxicity and early disease progression., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The facilitative GLUT1 and GLUT3 hexose transporters are expressed abundantly in macrophages, but whether they have distinct functions remains unclear. We confirmed that GLUT1 expression increased after M1 polarization stimuli and found that GLUT3 expression increased after M2 stimulation in macrophages. Conditional deletion of Glut3 (LysM-Cre Glut3fl/fl) impaired M2 polarization of bone marrow-derived macrophages. Alternatively activated macrophages from the skin of patients with atopic dermatitis showed increased GLUT3 expression, and a calcipotriol-induced model of atopic dermatitis was rescued in LysM-Cre Glut3fl/fl mice. M2-like macrophages expressed GLUT3 in human wound tissues as assessed by transcriptomics and costaining, and GLUT3 expression was significantly decreased in nonhealing, compared with healing, diabetic foot ulcers. In an excisional wound healing model, LysM-Cre Glut3fl/fl mice showed significantly impaired M2 macrophage polarization and delayed wound healing. GLUT3 promoted IL-4/STAT6 signaling, independently of its glucose transport activity. Unlike plasma membrane-localized GLUT1, GLUT3 was localized primarily to endosomes and was required for the efficient endocytosis of IL-4Rα subunits. GLUT3 interacted directly with GTP-bound RAS in vitro and in vivo through its intracytoplasmic loop domain, and this interaction was required for efficient STAT6 activation and M2 polarization. PAK activation and macropinocytosis were also impaired without GLUT3, suggesting broader roles for GLUT3 in the regulation of endocytosis. Thus, GLUT3 is required for efficient alternative macrophage polarization and function, through a glucose transport-independent, RAS-mediated role in the regulation of endocytosis and IL-4/STAT6 activation.

Measurements of kinase activity are important for kinase-directed drug development, analysis of inhibitor structure and function, and understanding mechanisms of drug resistance. Sensitive, accurate, and miniaturized assay methods are crucial for these investigations. Here, we describe a label-free, high-throughput mass spectrometry-based assay for studying individual kinase enzymology and drug discovery in a purified system, with a focus on validated drug targets as benchmarks. We demonstrate that this approach can be adapted to many known kinase substrates and highlight the benefits of using mass spectrometry to measure kinase activity in vitro , including increased sensitivity. We speculate that this approach to measuring kinase activity will be generally applicable across most of the kinome, enabling research on understudied kinases and kinase drug discovery.

Background: Prolonged treatment of HER2+ breast cancer with lapatinib (LAP) causes cellular senescence and acquired drug resistance, which often associating with poor prognosis for patients. We aim to explore the correlation between cellular senescence and LAP resistance in HER2+ breast cancer, screen for molecular marker of reversible senescence, and construct targeted nanobubbles for ultrasound molecular imaging to dynamically evaluate LAP resistance., Methods and Results: In this study, we established a new cellular model of reversible cellular senescence using LAP and HER2+ breast cancer cells and found that reversible senescence contributed to LAP resistance in HER2+ breast cancer. Then, we identified ecto-5'-nucleotidase (NT5E) as a marker of reversible senescence in HER2+ breast cancer. Based on this, we constructed NT5E-targeted nanobubbles (NT5E-FITC-NBs) as a new molecular imaging modality which could both target reversible senescent cells and be used for ultrasound imaging. NT5E-FITC-NBs showed excellent physical and imaging characteristics. As an ultrasound contrast agent, NT5E-FITC-NBs could accurately identify reversible senescent cells both in vitro and in vivo., Conclusions: Our data demonstrate that cellular senescence-based ultrasound-targeted imaging can identify reversible senescence and evaluate LAP resistance effectively in HER2+ breast cancer cells, which has the potential to improve cancer treatment outcomes by altering therapeutic strategies ahead of aggressive recurrences., (© 2023 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

The c-Jun N-terminal kinases (JNKs) are members of the mitogen-activated protein kinase (MAPK) family, which includes JNK1-JNK3. Interestingly, JNK1 and JNK2 show opposing functions, with JNK2 activity favoring cell survival and JNK1 stimulating apoptosis. Isoform-selective small molecule inhibitors of JNK1 or JNK2 would be useful as pharmacological probes but have been difficult to develop due to the similarity of their ATP binding pockets. Here, we describe the discovery of a covalent inhibitor YL5084, the first such inhibitor that displays selectivity for JNK2 over JNK1. We demonstrated that YL5084 forms a covalent bond with Cys116 of JNK2, exhibits a 20-fold higher K inact / K I compared to that of JNK1, and engages JNK2 in cells. However, YL5084 exhibited JNK2-independent antiproliferative effects in multiple myeloma cells, suggesting the existence of additional targets relevant in this context. Thus, although not fully optimized, YL5084 represents a useful chemical starting point for the future development of JNK2-selective chemical probes.

Cyclin-dependent kinases (CDK) are attractive targets for drug discovery due to their wide range of cellular functions. CDK11 is an understudied CDK with roles in transcription and splicing, cell cycle regulation, neuronal function, and apoptosis. In this study, we describe a medicinal chemistry campaign to identify a CDK11 inhibitor. Employing a promising but nonselective CDK11-targeting scaffold (JWD-047), extensive structure-guided medicinal chemistry modifications led to the identification of ZNL-05-044. A combination of biochemical evaluations and NanoBRET cellular assays for target engagement guided the SAR towards a 2,4-diaminothiazoles CDK11 probe with significantly improved kinome-wide selectivity over JWD-047. CDK11 inhibition with ZNL-05-044 leads to G2/M cell cycle arrest, consistent with prior work evaluating OTS964, and impacts CDK11-dependent mRNA splicing in cells. Together, ZNL-05-044 serves as a tool compound for further optimization and interrogation of the consequences of CDK11 inhibition., (Copyright © 2022. Published by Elsevier Masson SAS.)

Thermal unfolding methods are commonly used as a predictive technique by tracking the protein's physical properties. Inherent protein thermal stability and unfolding profiles of biotherapeutics can help to screen or study potential drugs and to find stabilizing or destabilizing conditions. Differential scanning calorimetry (DSC) is a 'Gold Standard' for thermal stability assays (TSA), but there are also a multitude of other methodologies, such as differential scanning fluorimetry (DSF). The use of an external probe increases the assay throughput, making it more suitable for screening studies, but the current methodologies suffer from relatively low sensitivity. While DSF is an effective tool for screening, interpretation and comparison of the results is often complicated. To overcome these challenges, we compared three thermal stability probes in small GTPase stability studies: SYPRO Orange, 8-anilino-1-naphthalenesulfonic acid (ANS), and the Protein-Probe. We studied mainly KRAS, as a proof of principle to obtain biochemical knowledge through TSA profiles. We showed that the Protein-Probe can work at lower concentration than the other dyes, and its sensitivity enables effective studies with non-covalent and covalent drugs at the nanomolar level. Using examples, we describe the parameters, which must be taken into account when characterizing the effect of drug candidates, of both small molecules and Designed Ankyrin Repeat Proteins.

Purpose: Five-fraction stereotactic ablative radiotherapy (SABR) regimens are frequently used to treat centrally located early-stage non-small cell lung cancer or disease in the proximity of the chest wall as a means of optimizing tumor control and reducing treatment toxicity. However, increasing these SABR regimens to 5 fractions may reduce tumor control outcomes. We sought to identify the clinical parameters predictive of treatment failures with these 5-fraction courses., Methods: Ninety patients with T1-2 non-small cell lung cancer were treated with 50 or 60 Gy in 5 fractions. Failure over time was modeled using cumulative incidences of local, regional, or distant failure, with death as a competing risk. Cox proportional hazards analysis for incidences of failure was performed to control for patient variables., Results: Of 90 patients, 24 of 53 patients with T1 tumors and 19 of 37 patients with T2 tumors received 50 Gy SABR, and the other 47 patients received 60 Gy. Two-year overall survival and progression-free survival for the whole cohort were 75.8% and 59.3%, respectively. Total SABR dose (50 vs 60 Gy) did not influence survival nor failure rates at 2 and 5 years. Within 2 years of treatment, 7.8% of all patients developed local failure. For all patient and tumor characteristics evaluated, only T stage and pretreatment positron emission tomography standardized uptake values served as predictors of local, regional, and distant failure at 2 and 5 years posttreatment on univariate and multivariable analysis., Conclusions: Five-fraction SABR provides excellent in-field control. T2 and high fluorodeoxyglucose uptake tumors have increased failure rates, suggesting the potential need for adjuvant therapies, which are being assessed in randomized phase 3 trials.

Immune stimulation fuels cell signaling-transcriptional programs inducing biological responses to eliminate virus-infected cells. Yet, retroviruses that integrate into host cell chromatin, such as HIV-1, co-opt these programs to switch between latent and reactivated states; however, the regulatory mechanisms are still unfolding. Here, we implemented a functional screen leveraging HIV-1's dependence on CD4 + T cell signaling-transcriptional programs and discovered ADAP1 is an undescribed modulator of HIV-1 proviral fate. Specifically, we report ADAP1 (ArfGAP with dual PH domain-containing protein 1), a previously thought neuronal-restricted factor, is an amplifier of select T cell signaling programs. Using complementary biochemical and cellular assays, we demonstrate ADAP1 inducibly interacts with the immune signalosome to directly stimulate KRAS GTPase activity thereby augmenting T cell signaling through targeted activation of the ERK-AP-1 axis. Single cell transcriptomics analysis revealed loss of ADAP1 function blunts gene programs upon T cell stimulation consequently dampening latent HIV-1 reactivation. Our combined experimental approach defines ADAP1 as an unexpected tuner of T cell programs facilitating HIV-1 latency escape., (© 2022. The Author(s).)

Cancer cells evade immune detection via programmed cell death 1/programmed cell death-ligand 1 (PD-1/PD-L1) interactions that inactivate T cells. PD-1/PD-L1 blockade has become an important therapy in the anti-cancer armamentarium. However, some patients do not benefit from PD-1/PD-L1 blockade despite expressing PD-L1. Here, we screened 101 gastric cancer (GC) patients at diagnosis and 141 healthy control subjects and reported one such subpopulation of GC patients with rs17718883 polymorphism in PD-L1, resulting in a nonsense P146R mutation. We detected rs17718883 in 44% of healthy control subjects, and rs17718883 was associated with a low susceptibility to GC and better prognosis in GC patients. Structural analysis suggests that the mutation weakens the PD-1:PD-L1 interaction. This was supported by co-culture experiments of T cells, with GC cells showing that the P146R substitution results in interferon (IFN)-γ secretion by T cells and enables T cells to suppress GC cell growth. Similar results with animal gastric tumor models were obtained in vivo. PD-1 monoclonal antibody treatment did not enhance the inhibitory effect of T cells on GC cells expressing PD-L1 P146R in vitro or in vivo. This study suggests that rs17718883 is common and may be used as a biomarker for exclusion from PD-1/PD-L1 blockade therapy., Competing Interests: Declaration of interests K.D.W. has received consulting fees from Sanofi Oncology, is a member of the SAB for Vibliome Therapeutics, and has or had sponsored research agreements with Astellas Pharmaceuticals and Revolution Medicine. K.D.W. declares that none of these relationships is directly or indirectly related to the content of this manuscript. The other authors declare no competing interests., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)

Quinazolin-dione- N -3-alklyl derivatives are the core scaffolds for several categories of bioactive small molecules, but current synthetic methods are costly, involve environmental hazards, and are not uniformly scalable. Here, we report an inexpensive, flexible, and scalable method for the one-pot synthesis of substituted quinazolin-dione- N -3-alkyls (isomers of isatoic-8-secondary amides (IASAs)) from isatin that take advantage of in situ capture of imidic acid under acidic conditions. We further show that this method can be used for the synthesis of a wide variety of derivatives with medicinal uses.

The protein K-Ras functions as a molecular switch in signaling pathways regulating cell growth. In the human mitogen-activated protein kinase (MAPK) pathway, which is implicated in many cancers, multiple K-Ras proteins are thought to assemble at the cell membrane with Ras effector proteins from the Raf family. Here we propose an atomistic structural model for such an assembly. Our starting point was an asymmetric guanosine triphosphate-mediated K-Ras dimer model, which we generated using unbiased molecular dynamics simulations and verified with mutagenesis experiments. Adding further K-Ras monomers in a head-to-tail fashion led to a compact helical assembly, a model we validated using electron microscopy and cell-based experiments. This assembly stabilizes K-Ras in its active state and presents composite interfaces to facilitate Raf binding. Guided by existing experimental data, we then positioned C-Raf, the downstream kinase MEK1 and accessory proteins (Galectin-3 and 14-3-3σ) on and around the helical assembly. The resulting Ras-Raf signalosome model offers an explanation for a large body of data on MAPK signaling., (© 2021. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Identifying resistance mutations in a drug target provides crucial information. Lentiviral transduction creates multiple types of mutations due to the error-prone nature of the HIV-1 reverse transcriptase (RT). Here we optimized and leveraged this property to identify drug resistance mutations, developing a technique we term LentiMutate. This technique was validated by identifying clinically relevant EGFR resistance mutations, then applied to two additional clinical anticancer drugs: imatinib, a BCR-ABL inhibitor, and AMG 510, a KRAS G12C inhibitor. Novel deletions in BCR-ABL1 conferred resistance to imatinib. In KRAS-G12C or wild-type KRAS, point mutations in the AMG 510 binding pocket or oncogenic non-G12C mutations conferred resistance to AMG 510. LentiMutate should prove highly valuable for clinical and preclinical cancer-drug development. SIGNIFICANCE: LentiMutate can evaluate a drug's on-target activity and can nominate resistance mutations before they occur in patients, which could accelerate and refine drug development to increase the survival of patients with cancer., (©2021 The Authors; Published by the American Association for Cancer Research.)

Background: Metastasis is a major challenge in cervical cancer treatment. Previous studies have shown that the dual functional protein apurinic/apyrimidinic endonuclease 1 (APE1) promotes tumor metastasis and is overexpressed in cervical cancer. However, the biological role and mechanism of APE1 in cervical cancer metastasis have rarely been studied., Methods: We used gene set enrichment analysis (GSEA) to determine the APE1-related signaling pathways in cervical cancer. To investigate the role and mechanism of APE1 in cervical cancer metastasis and invasion, immunohistochemistry, immunofluorescence, western blotting, secondary structure prediction, coimmunoprecipitation, luciferase reporter, and electrophoretic mobility shift assays were performed. The inhibitory effects of the APE1 redox function inhibitor APX3330 on cervical cancer metastasis were evaluated using animal models., Results: Clinical data showed that high expression of APE1 was associated with lymph node metastasis in cervical cancer patients. GSEA results showed that APE1 was associated with epithelial to mesenchymal transition (EMT) in cervical cancer. Ectopic expression of APE1 promoted EMT and invasion of cervical cancer cells, whereas inhibition of APE1 suppressed EMT and invasion of cervical cancer cells in a redox function-dependent manner. Notably, APE1 redox function inhibitor APX3330 treatment dramatically suppressed cervical cancer cell lymph node and distant metastasis in vivo. Furthermore, we found that APE1 enhanced the interaction between ZEB1 and the E-cadherin promoter by binding to ZEB1, thereby suppressing the expression of E-cadherin, a negative regulator of EMT., Conclusion: Our findings help to elucidate the role played by APE1 in cervical cancer metastasis and targeting APE1 redox function may be a novel strategy for inhibiting cervical cancer metastasis.

Peptide mobility shift assays provide a sensitive measure of kinase enzymatic activity and can be used to evaluate kinase inhibitors. Herein, we describe a protocol adapted for rapid assessment of doublecortin-like kinase inhibitors. Advantages include rapid iterations of therapeutic compound assessment and the ability to characterize kinase mutations, such as drug-resistant mutants for biological rescue experiments, on kinase activity. For complete details on the use and execution of this protocol, please refer to Liu et al. (2020)., Competing Interests: K.D.W. has received consulting fees from Sanofi Oncology and is a member of the SAB for Vibliome Therapeutics. K.D.W. has received research funding from Revolution Medicines. K.D.W. declares that none of these relationships are directly or indirectly related to the content of this manuscript., (© 2021 The Author(s).)

The functions of Ras members are largely governed by the structural dynamics of the nucleotide-binding switch regions. In this issue of Structure, Lin et al. (2021) take a close look at the dynamic equilibrium of RhoA, the founding member of the Rho family of Ras GTPases., Competing Interests: Declaration of interests K.D.W. has received consulting fees from Sanofi Oncology, is a member of the SAB for Vibliome Therapeutics, and has or had sponsored research agreements with Astellas Pharmaceuticals and Revolution Medicine. K.D.W. declares that none of these relationships are directly or indirectly related to the content of this manuscript., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Nutrient-responsive protein kinases control the balance between anabolic growth and catabolic processes such as autophagy. Aberrant regulation of these kinases is a major cause of human disease. We report here that the vertebrate nonreceptor tyrosine kinase Src-related kinase lacking C-terminal regulatory tyrosine and N-terminal myristylation sites (SRMS) inhibits autophagy and promotes growth in a nutrient-responsive manner. Under nutrient-replete conditions, SRMS phosphorylates the PHLPP scaffold FK506-binding protein 51 (FKBP51), disrupts the FKBP51-PHLPP complex, and promotes FKBP51 degradation through the ubiquitin-proteasome pathway. This prevents PHLPP-mediated dephosphorylation of AKT, causing sustained AKT activation that promotes growth and inhibits autophagy. SRMS is amplified and overexpressed in human cancers where it drives unrestrained AKT signaling in a kinase-dependent manner. SRMS kinase inhibition activates autophagy, inhibits cancer growth, and can be accomplished using the FDA-approved tyrosine kinase inhibitor ibrutinib. This illuminates SRMS as a targetable vulnerability in human cancers and as a new target for pharmacological induction of autophagy in vertebrates., Competing Interests: I have read he journal’s policy and the authors of this manuscript have the following competing interests: J.M.P., S.W.Y., and M.B.P. are employees and shareholders of Amgen. Author Sergei von Hoyningen-Huene was unavailable to confirm their authorship contributions. On their behalf, the corresponding author has reported their contributions to the best of their knowledge.

Objectives: Wild type RAS (RAS WT ) suppresses the function of oncogenic RAS mutants (RAS MUT ) in laboratory models. Loss of RAS WT , which we termed loss of heterozygosity (LOH) for any RAS (LAR) or LAKR in the context of KRAS (LOH at KRAS), is found in patients with RAS MUT cancers. However, the incidence and prognostic significance of LAR has not been studied in modern patient cohorts. LAR or LAKR in RAS MUT cancers is attractive as a potential biomarker for targeted therapy., Materials and Methods: We evaluated for associations between LAKR and cancer mortality in patients with KRAS MUT lung adenocarcinoma (LUAD). We also evaluated for associations between LAKR and the metabolic state of cancer cell lines, given that KRAS has been shown to regulate fatty acid synthesis. In line with this, we investigated fatty acid synthase (FASN) inhibitors as potential therapies for KRAS MUT LAKR, including combination strategies involving clinical KRAS G12C and FASN inhibitors., Results: 24 % of patients with KRAS MUT LUAD showed LAKR. KRAS MUT LAKR cases had a median survival of 16 vs. 30 months in KRAS MUT non-LAKR (p =  0.017) and LAKR was independently associated with death in this cohort (p =  0.011). We also found that KRAS MUT LUAD cell lines with LAKR contained elevated levels of FASN and fatty acids relative to non-LAKR cell lines. KRAS MUT LUAD cells with LAKR showed higher sensitivity to treatment with FASN inhibitors than those without. FASN inhibitors such as TVB-3664 showed synergistic effects with the KRAS G12C inhibitor MRTX849 in LUAD cells with KRAS G12C and LAKR, including an in vivo trial using a xenograft model., Conclusions: LAKR in KRAS MUT cancers may represent an independent negative prognostic factor for patients with KRAS MUT LUAD. It also predicts for response to treatment with FASN inhibitors. Prospective testing of combination therapies including KRAS G12C and FASN inhibitors in patients with KRAS G12C LAKR is warranted., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Advanced radiotherapeutic treatment techniques limit the cognitive morbidity associated with whole-brain radiotherapy (WBRT) for brain metastasis through avoidance of hippocampal structures. However, achieving durable intracranial control remains challenging., Methods: We conducted a single-institution single-arm phase II trial of hippocampal-sparing whole brain irradiation with simultaneous integrated boost (HSIB-WBRT) to metastatic deposits in adult patients with brain metastasis. Radiation therapy consisted of intensity-modulated radiation therapy delivering 20 Gy in 10 fractions over 2-2.5 weeks to the whole brain with a simultaneous integrated boost of 40 Gy in 10 fractions to metastatic lesions. Hippocampal regions were limited to 16 Gy. Cognitive performance and cancer outcomes were evaluated., Results: A total of 50 patients, median age 60 years (interquartile range, 54-65), were enrolled. Median progression-free survival was 2.9 months (95% CI: 1.5-4.0) and overall survival was 9 months. As expected, poor survival and end-of-life considerations resulted in a high exclusion rate from cognitive testing. Nevertheless, mean decline in Hopkins Verbal Learning Test-Revised delayed recall (HVLT-R DR) at 3 months after HSIB-WBRT was only 10.6% (95% CI: -36.5‒15.3%). Cumulative incidence of local and intracranial failure with death as a competing risk was 8.8% (95% CI: 2.7‒19.6%) and 21.3% (95% CI: 10.7‒34.2%) at 1 year, respectively. Three grade 3 toxicities consisting of nausea, vomiting, and necrosis or headache were observed in 3 patients. Scores on the Multidimensional Fatigue Inventory 20 remained stable for evaluable patients at 3 months., Conclusions: HVLT-R DR after HSIB-WBRT was significantly improved compared with historical outcomes in patients treated with traditional WBRT, while achieving intracranial control similar to patients treated with WBRT plus stereotactic radiosurgery (SRS). This technique can be considered in select patients with multiple brain metastases who cannot otherwise receive SRS., (© The Author(s) 2020. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Doublecortin-like kinase 1 (DCLK1) is critical for neurogenesis, but overexpression is also observed in multiple cancers and is associated with poor prognosis. Nevertheless, the function of DCLK1 in cancer, especially the context-dependent functions, are poorly understood. We present a "toolkit" that includes the DCLK1 inhibitor DCLK1-IN-1, a complementary DCLK1-IN-1-resistant mutation G532A, and kinase dead mutants D511N and D533N, which can be used to investigate signaling pathways regulated by DCLK1. Using a cancer cell line engineered to be DCLK1 dependent for growth and cell migration, we show that this toolkit can be used to discover associations between DCLK1 kinase activity and biological processes. In particular, we show an association between DCLK1 and RNA processing, including the identification of CDK11 as a potential substrate of DCLK1 using phosphoproteomics., Competing Interests: Declaration of Interests F.M.F. and N.S.G. are inventors on a patent application related to the DCLK1 inhibitors described in this manuscript (WO/2018/075608). K.D.W. has received consulting fees from Sanofi Oncology and is a member of the SAB for Vibliome Therapeutics. K.D.W. declares that none of these relationships are directly or indirectly related to the content of this manuscript. N.S.G. is a Scientific Founder, member of the SAB, and equity holder in C4 Therapeutics, Syros, Soltego (board member), B2S, Aduro Gatekeeper, and Petra Pharmaceuticals. The Gray lab receives or has received research funding from Novartis, Takeda, Astellas, Taiho, Janssen, Kinogen, Voroni, Her2llc, Deerfield, and Sanofi. P.K.S. is a member of the SAB or Board of Directors of Applied Biomath and RareCyte, Inc., and has equity in these companies. P.K.S. has received research funding from Novartis and Merck in the last 5 years. P.K.S. declares that none of these relationships are directly or indirectly related to the content of this manuscript. P.K.S. is a current employee of Bristol-Myers Squibb., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Assembly of RAS molecules into complexes at the cell membrane is critical for RAS signaling. We previously showed that oncogenic KRAS codon 61 mutations increase its affinity for RAF, raising the possibility that KRAS Q61H , the most common KRAS mutation at codon 61, upregulates RAS signaling through mechanisms at the level of RAS assemblies. We show here that KRAS Q61H exhibits preferential binding to RAF relative to PI3K in cells, leading to enhanced MAPK signaling in in vitro models and human NSCLC tumors. X-ray crystallography of KRAS Q61H :GTP revealed that a hyperdynamic switch 2 allows for a more stable interaction with switch 1, suggesting that enhanced RAF activity arises from a combination of absent intrinsic GTP hydrolysis activity and increased affinity for RAF. Disruption of KRAS Q61H assemblies by the RAS oligomer-disrupting D154Q mutation impaired RAF dimerization and altered MAPK signaling but had little effect on PI3K signaling. However, KRAS Q61H oligomers but not KRAS G12D oligomers were disrupted by RAF mutations that disrupt RAF-RAF interactions. KRAS Q61H cells show enhanced sensitivity to RAF and MEK inhibitors individually, whereas combined treatment elicited synergistic growth inhibition. Furthermore, KRAS Q61H tumors in mice exhibited high vulnerability to MEK inhibitor, consistent with cooperativity between KRAS Q61H and RAF oligomerization and dependence on MAPK signaling. These findings support the notion that KRAS Q61H and functionally similar mutations may serve as predictive biomarkers for targeted therapies against the MAPK pathway. SIGNIFICANCE: These findings show that oncogenic KRAS Q61H forms a cooperative RAS-RAF ternary complex, which renders RAS-driven tumors vulnerable to MEKi and RAFi, thus establishing a framework for evaluating RAS biomarker-driven targeted therapies., (©2020 American Association for Cancer Research.)

Doublecortin-like kinase 1 (DCLK1) is a serine/threonine kinase that is overexpressed in gastrointestinal cancers, including esophageal, gastric, colorectal, and pancreatic cancers. DCLK1 is also used as a marker of tuft cells, which regulate type II immunity in the gut. However, the substrates and functions of DCLK1 are understudied. We recently described the first selective DCLK1/2 inhibitor, DCLK1-IN-1, developed to aid the functional characterization of this important kinase. Here we describe the synthesis and structure-activity relationships of 5,11-dihydro-6 H -benzo[ e ]pyrimido[5,4- b ][1,4]diazepin-6-one DCLK1 inhibitors, resulting in the identification of DCLK1-IN-1.

Doublecortin like kinase 1 (DCLK1) is an understudied kinase that is upregulated in a wide range of cancers, including pancreatic ductal adenocarcinoma (PDAC). However, little is known about its potential as a therapeutic target. We used chemoproteomic profiling and structure-based design to develop a selective, in vivo-compatible chemical probe of the DCLK1 kinase domain, DCLK1-IN-1. We demonstrate activity of DCLK1-IN-1 against clinically relevant patient-derived PDAC organoid models and use a combination of RNA-sequencing, proteomics and phosphoproteomics analysis to reveal that DCLK1 inhibition modulates proteins and pathways associated with cell motility in this context. DCLK1-IN-1 will serve as a versatile tool to investigate DCLK1 biology and establish its role in cancer.

RAS proteins are commonly mutated in cancerous tumors, but germline RAS mutations are also found in RASopathy syndromes such as Noonan syndrome (NS) and cardiofaciocutaneous (CFC) syndrome. Activating RAS mutations can be subclassified based on their activating mechanisms. Understanding the structural basis for these mechanisms may provide clues for how to manage associated health conditions. We determined high-resolution X-ray structures of the RASopathy mutant KRAS P34R seen in NS and CFCS. GTP and GDP-bound KRAS P34R crystallized in multiple forms, with each lattice consisting of multiple protein conformations. In all GTP-bound conformations, the switch regions are not compatible with GAP binding, suggesting a structural mechanism for the GAP insensitivity of this RAS mutant. However, GTP-bound conformations are compatible with intrinsic nucleotide hydrolysis, including one that places R34 in a position analogous to the GAP arginine finger or intrinsic arginine finger found in heterotrimeric G proteins, which may support intrinsic GTP hydrolysis. We also note that the affinity between KRAS P34R and RAF-RBD is decreased, suggesting another possible mechanism for dampening of RAS signaling. These results may provide a foothold for development of new mutation-specific strategies to address KRAS P34R -driven diseases., (© 2020 Wiley Periodicals, Inc.)

Unregulated Src activity promotes malignant processes in cancer, but no Src-directed targeted therapies are used clinically, possibly because early Src inhibitors produce off-target effects leading to toxicity. Improved selective Src inhibitors may enable Src-directed therapies. Previously, we reported an irreversible Src inhibitor, DGY-06-116, based on the hybridization of dasatinib and a promiscuous covalent kinase probe SM1-71. Here, we report biochemical and biophysical characterization of this compound. An x-ray co-crystal structure of DGY-06-116: Src shows a covalent interaction with the kinase p-loop and occupancy of the back hydrophobic kinase pocket, explaining its high potency, and selectivity. However, a reversible analog also shows similar potency. Kinetic analysis shows a slow inactivation rate compared to other clinically approved covalent kinase inhibitors, consistent with a need for p-loop movement prior to covalent bond formation. Overall, these results suggest that a strong reversible interaction is required to allow sufficient time for the covalent reaction to occur. Further optimization of the covalent linker may improve the kinetics of covalent bond formation., (Copyright © 2020 Gurbani, Du, Henning, Rao, Bera, Zhang, Gray and Westover.)

Tamoxifen-based hormone therapy is central for the treatment of estrogen receptor positive (ER + ) breast cancer. However, the acquired tamoxifen resistance, typically co-exists with hypoxia, remains a major challenge. We aimed to develop a non-invasive, targeted ultrasound imaging approach to dynamically monitory of tamoxifen resistance. After we assessed acquired tamoxifen resistance in 235 breast cancer patients and a list of breast cancer cell lines, we developed poly(lactic-co-glycolic acid)-poly(ethylene glycol)-carbonic anhydrase IX mono antibody nanobubbles (PLGA-PEG-mAb CAIX NBs) to detect hypoxic breast cancer cells upon exposure of tamoxifen in nude mice. We demonstrate that carbonic anhydrase IX (CAIX) expression is associated with breast cancer local recurrence and tamoxifen resistance both in clinical and cellular models. We find that CAIX overexpression increases tamoxifen tolerance in MCF-7 cells and predicts early tamoxifen resistance along with an oscillating pattern in intracellular ATP level in vitro. PLGA-PEG-mAb CAIX NBs are able to dynamically detect tamoxifen-induced hypoxia and tamoxifen resistance in vivo. CAIX-conjugated NBs with noninvasive ultrasound imaging is powerful for dynamically monitoring hypoxic microenvironment in ER + breast cancer with tamoxifen resistance., (© 2020 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

SRC is a major regulator of many signaling pathways and contributes to cancer development. However, development of a selective SRC inhibitor has been challenging, and FDA-approved SRC inhibitors, dasatinib and bosutinib, are multitargeted kinase inhibitors. Here, we describe our efforts to develop a selective SRC covalent inhibitor by targeting cysteine 277 on the P-loop of SRC. Using a promiscuous covalent kinase inhibitor (CKI) SM1-71 as a starting point, we developed covalent inhibitor 15a , which discriminates SRC from other covalent targets of SM1-71 including TAK1 and FGFR1. As an irreversible covalent inhibitor, compound 15a exhibited sustained inhibition of SRC signaling both in vitro and in vivo . Moreover, 15a exhibited potent antiproliferative effects in nonsmall cell lung cancer cell lines harboring SRC activation, thus providing evidence that this approach may be promising for further drug development efforts.

Interleukin-1 receptor-associated kinase-1 (IRAK-1) and IRAK-4, as well as transforming growth factor β-activated kinase 1 (TAK1), are protein kinases essential for transducing inflammatory signals from interleukin receptors. IRAK family proteins and TAK1 have high sequence identity within the ATP-binding pocket, limiting the development of highly selective IRAK-1/4 or TAK1 inhibitors. Beyond kinase activity, IRAKs and TAK1 act as molecular scaffolds along with other signaling proteins, complicating the interpretation of experiments involving knockin or knockout approaches. In contrast, pharmacological manipulation offers the promise of targeting catalysis-mediated signaling without grossly disrupting the cellular architecture. Recently, we reported the discovery of takinib, a potent and highly selective TAK1 inhibitor that has only marginal activity against IRAK-4. On the basis of the TAK1-takinib complex structure and the structure of IRAK-1/4, here we defined critical contact sites of the takinib scaffold within the nucleotide-binding sites of each respective kinase. Kinase activity testing of takinib analogs against IRAK-4 identified a highly potent IRAK-4 inhibitor (HS-243). In a kinome-wide screen of 468 protein kinases, HS-243 had exquisite selectivity toward both IRAK-1 (IC 50 = 24 nm) and IRAK-4 (IC 50 = 20 nm), with only minimal TAK1-inhibiting activity (IC 50 = 0.5 μm). Using HS-243 and takinib, we evaluated the consequences of cytokine/chemokine responses after selective inhibition of IRAK-1/4 or TAK1 in response to lipopolysaccharide challenge in human rheumatoid arthritis fibroblast-like synoviocytes. Our results indicate that HS-243 specifically inhibits intracellular IRAKs without TAK1 inhibition and that these kinases have distinct, nonredundant signaling roles., (© 2020 Scarneo et al.)

KRAS is the most frequently mutated oncogene found in pancreatic, colorectal, and lung cancers. Although it has been challenging to identify targeted therapies for cancers harboring KRAS mutations, KRAS G12C can be targeted by small-molecule inhibitors that form covalent bonds with cysteine 12 (C12). Here, we designed a library of C12-directed covalent degrader molecules (PROTACs) and subjected them to a rigorous evaluation process to rapidly identify a lead compound. Our lead degrader successfully engaged CRBN in cells, bound KRAS G12C in vitro, induced CRBN/KRAS G12C dimerization, and degraded GFP-KRAS G12C in reporter cells in a CRBN-dependent manner. However, it failed to degrade endogenous KRAS G12C in pancreatic and lung cancer cells. Our data suggest that inability of the lead degrader to effectively poly-ubiquitinate endogenous KRAS G12C underlies the lack of activity. We discuss challenges for achieving targeted KRAS G12C degradation and proposed several possible solutions which may lead to efficient degradation of endogenous KRAS G12C ., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Synthetic methods used to generate substituted anilines and quinazolines, both privileged pharmacological structures, are cumbersome, hazardous or, in some cases, unavailable. We developed a straightforward method for making isatoic anhydride-8-amide from isatin-7-carboxylic acid as a tool to easily produce a range of quinazoline and substituted aniline derivatives using adaptable pH-sensitive cyclization chemistry. The approaches are inexpensive, simple, fast, efficient at room temperature and scalable, enabling the synthesis of both established and new quinazolines and also highly substituted anilines including cyano derivatives.

RAS regulation and signaling are largely accomplished by direct protein-protein interactions, making RAS protein dynamics a critical determinant of RAS function. Here, we report a crystal structure of GDP-bound KRAS V14I , a mutated KRAS variant associated with the developmental RASopathy disorder Noonan syndrome (NS), at 1.5-1.6 Å resolution. The structure is notable for revealing a marked extension of switch 1 away from the G-domain and nucleotide-binding site of the KRAS protein. We found that this extension is associated with a loss of the magnesium ion and a tilt in the position of the guanine base because of the additional carbon introduced by the isoleucine substitution. Hydrogen-deuterium exchange MS analysis confirmed that this conformation occurs in solution, but also disclosed a difference in kinetics when compared with KRAS A146T , another RAS mutant that displays a nearly identical conformation in previously reported crystal structures. This conformational change contributed to a high rate of guanine nucleotide-exchange factor (GEF)-dependent and -independent nucleotide exchange and to an increase in affinity for SOS Ras/Rac GEF 1 (SOS1), which appears to be the major mode of activation for this RAS variant. These results highlight a mechanistic connection between KRAS A146T and KRAS V14I that may have implications for the regulation of these variants and for the development of therapeutic strategies to manage KRAS variant-associated disorders., (© 2019 Bera et al.)

Background: Epithelial-mesenchymal transition (EMT) is critical for cancer cell metastasis. Recently, EMT was reported to be associated with the inflammatory tumour microenvironment and, therefore, might be a predictive biomarker for immune checkpoint blockade agents. However, the underlying mechanism is still unclear., Methods: Patient survival data for our HCC cohort, TCGA and GEO datasets were determined by Kaplan-Meier analysis. The functional roles of ELMO1 in HCC were demonstrated by a series of in vitro and in vivo experiments. Gene microarray analysis was used to demonstrate potential mechanisms of ELMO1. Data retrieved from the TCGA datasets were used to determine the relationships of ELMO1, EMT and TMB., Findings: Here, we report an indispensable role for ELMO1 in linking EMT with tumour mutation burden (TMB), which is a promising biomarker for the immune checkpoint blockade agent response. Upregulated ELMO1 expression is associated with a poor prognosis in hepatocellular carcinoma (HCC), as well as increased cell growth, invasion, migration, angiogenesis and EMT in vitro and in vivo. Mechanistically, we provide evidence that ELMO1 regulates SOX10 expression and induces EMT through PI3K/Akt signalling. Moreover, ELMO1 is negatively associated with TMB, indicating a negative relationship between EMT and TMB., Interpretation: ELMO1 serves as a link between EMT and TMB, providing a mechanistic basis for the further development of ELMO1 as a therapeutic target against HCC and potentially a promising biomarker of the immune checkpoint blockade agent response. FUND: National Natural Science Foundation of China; Natural Science Foundation of Guangdong Province; Young Teacher Training Program of Sun Yat-sen University; Science and Technology Plan of Guangdong Province; Special Support Program of Guangdong Province, Science and Technology Innovation Youth Talent Support Program; the Pearl River Science and Technology New Talent of Guangzhou City; Medical Scientific Research Foundation of Guangdong Province., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)

Covalent kinase inhibitors, which typically target cysteine residues, represent an important class of clinically relevant compounds. Approximately 215 kinases are known to have potentially targetable cysteines distributed across 18 spatially distinct locations proximal to the ATP-binding pocket. However, only 40 kinases have been covalently targeted, with certain cysteine sites being the primary focus. To address this disparity, we have developed a strategy that combines the use of a multi-targeted acrylamide-modified inhibitor, SM1-71, with a suite of complementary chemoproteomic and cellular approaches to identify additional targetable cysteines. Using this single multi-targeted compound, we successfully identified 23 kinases that are amenable to covalent inhibition including MKNK2, MAP2K1/2/3/4/6/7, GAK, AAK1, BMP2K, MAP3K7, MAPKAPK5, GSK3A/B, MAPK1/3, SRC, YES1, FGFR1, ZAK (MLTK), MAP3K1, LIMK1, and RSK2. The identification of nine of these kinases previously not targeted by a covalent inhibitor increases the number of targetable kinases and highlights opportunities for covalent kinase inhibitor development., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Cyclin-dependent kinase 7 (CDK7) regulates both cell cycle and transcription, but its precise role remains elusive. We previously described THZ1, a CDK7 inhibitor, which dramatically inhibits superenhancer-associated gene expression. However, potent CDK12/13 off-target activity obscured CDK7s contribution to this phenotype. Here, we describe the discovery of a highly selective covalent CDK7 inhibitor. YKL-5-124 causes arrest at the G 1 /S transition and inhibition of E2F-driven gene expression; these effects are rescued by a CDK7 mutant unable to covalently engage YKL-5-124, demonstrating on-target specificity. Unlike THZ1, treatment with YKL-5-124 resulted in no change to RNA polymerase II C-terminal domain phosphorylation; however, inhibition could be reconstituted by combining YKL-5-124 and THZ531, a selective CDK12/13 inhibitor, revealing potential redundancies in CDK control of gene transcription. These findings highlight the importance of CDK7/12/13 polypharmacology for anti-cancer activity of THZ1 and posit that selective inhibition of CDK7 may be useful for treatment of cancers marked by E2F misregulation., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

KRAS is the most frequently mutated oncogene. The incidence of specific KRAS alleles varies between cancers from different sites, but it is unclear whether allelic selection results from biological selection for specific mutant KRAS proteins. We used a cross-disciplinary approach to compare KRAS G12D , a common mutant form, and KRAS A146T , a mutant that occurs only in selected cancers. Biochemical and structural studies demonstrated that KRAS A146T exhibits a marked extension of switch 1 away from the protein body and nucleotide binding site, which activates KRAS by promoting a high rate of intrinsic and guanine nucleotide exchange factor-induced nucleotide exchange. Using mice genetically engineered to express either allele, we found that KRAS G12D and KRAS A146T exhibit distinct tissue-specific effects on homeostasis that mirror mutational frequencies in human cancers. These tissue-specific phenotypes result from allele-specific signaling properties, demonstrating that context-dependent variations in signaling downstream of different KRAS mutants drive the KRAS mutational pattern seen in cancer. SIGNIFICANCE: Although epidemiologic and clinical studies have suggested allele-specific behaviors for KRAS , experimental evidence for allele-specific biological properties is limited. We combined structural biology, mass spectrometry, and mouse modeling to demonstrate that the selection for specific KRAS mutants in human cancers from different tissues is due to their distinct signaling properties. See related commentary by Hobbs and Der, p. 696 . This article is highlighted in the In This Issue feature, p. 681 ., (©2019 American Association for Cancer Research.)

Background: miRNAs play crucial role in the progression of K-Ras-mutated nonsmall cell lung cancer (NSCLC). However, most studies have focused on miRNAs that target K-Ras. Here, we investigated miRNAs regulated by mutant K-Ras and their functions., Methods: miRNAs regulated by mutant K-Ras were screened using miRNA arrays. miR-199b expression levels were measured by qRT-PCR. The protein expression levels were measured using Western blot and immunohistochemistry. The effects of miR-199b on NSCLC were examined both in vitro and in vivo by overexpressing or inhibiting miR-199b. DNA methylation was measured by bisulfite sequencing., Results: An inverse correlation was observed between K-Ras mutation status and miR-199b levels in NSCLC specimens and cell lines. The inhibition of miR-199b stimulated NSCLC growth and metastasis, while restoration of miR-199b suppressed K-Ras mutation-driven lung tumorigenesis as well as K-Ras-mutated NSCLC growth and metastasis. miR-199b inactivated ERK and Akt pathways by targeting K-Ras, KSR2, PIK3R1, Akt1, and Rheb1. Furthermore, we determined that mutant K-Ras inhibits miR-199b expression by increasing miR-199b promoter methylation., Conclusion: Our findings suggest that mutant K-Ras plays an oncogenic role through downregulating miR-199b in NSCLC and that overexpression of miR-199b is a novel strategy for the treatment of K-Ras-mutated NSCLC.

Purpose: Protraction of radiation therapy courses can lead to lower cancer control and cancer-specific survival rates. The requirement for daily, consecutive radiation treatments coupled with the complexities of multimodality cancer care and quality assurance can occasionally lead to missed patient appointments or clinical inefficiency. To determine whether an automated text messaging (short message service [SMs]) platform could improve patient compliance with scheduled radiation therapy delivery, we created an automated SMS platform to send daily reminders of radiation therapy appointments., Methods and Materials: An automated SMS text messaging program was used from July 2016 to January 2017 to deliver daily appointment time reminders to patients on an elective basis. Automated text messages were sent 2 hours before treatment appointments with appointment-specific information. We analyzed for compliance with radiation therapy appointments for patients who elected to receive SMS reminders versus those who did not., Results: Multivariate analysis of >37,000 encounters involving ∼3400 patients demonstrated that of the factors considered, nonreceipt of SMS appointment reminders had a strong association with 15- to 60-minute tardiness (odds ratio [OR], 1.25; 95% confidence interval [CI], 1.13-1.38; P < .0001), >60-minute tardiness (OR, 1.56; 95% CI, 1.34-1.82; P < .0001) and no-shows (OR, 6.77; 95% CI, 5.45-8.41; P < .0001). Other demographic factors associated with decreased compliance included being early in a radiation therapy course, having an appointment earlier in the day, younger age, and male sex. Receipt of an SMS message did not correlate with overall treatment package time., Conclusions: Receipt of text messages correlates with compliance for radiation therapy appointments. Prospective randomized trials would be required to determine conclusively whether SMS is an effective intervention for improving compliance in populations at risk for being late to or missing radiation therapy appointments., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Distant failure is the main cause of human cancer-related mortalities. To develop a model for predicting distant failure in non-small cell lung cancer (NSCLC) and cervix cancer (CC) patients, a shell feature, consisting of outer voxels around the tumor boundary, was constructed using pre-treatment positron emission tomography (PET) images from 48 NSCLC patients received stereotactic body radiation therapy and 52 CC patients underwent external beam radiation therapy and concurrent chemotherapy followed with high-dose-rate intracavitary brachytherapy. The hypothesis behind this feature is that non-invasive and invasive tumors may have different morphologic patterns in the tumor periphery, in turn reflecting the differences in radiological presentations in the PET images. The utility of the shell was evaluated by the support vector machine classifier in comparison with intensity, geometry, gray level co-occurrence matrix-based texture, neighborhood gray tone difference matrix-based texture, and a combination of these four features. The results were assessed in terms of accuracy, sensitivity, specificity, and AUC. Collectively, the shell feature showed better predictive performance than all the other features for distant failure prediction in both NSCLC and CC cohorts.

Radioresistance remains a major clinical challenge in cervical cancer therapy. However, the mechanism for the development of radioresistance in cervical cancer is unclear. Herein, we determined that growth arrest and DNA-damage-inducible protein 45α (GADD45α) is decreased in radioresistant cervical cancer compared to radiosensitive cancer both in vitro and in vivo. In addition, silencing GADD45α prevents cervical cancer cells from undergoing radiation-induced DNA damage, cell cycle arrest, and apoptosis. More importantly, our data show that the overexpression of GADD45α significantly enhances the radiosensitivity of radioresistant cervical cancer cells. These data show that GADD45α decreases the cytoplasmic distribution of APE1, thereby enhancing the radiosensitivity of cervical cancer cells. Furthermore, we show that GADD45α inhibits the production of nitric oxide (NO), a nuclear APE1 export stimulator, by suppressing both endothelial NO synthase (eNOS) and inducible NO synthase (iNOS) in cervical cancer cells. In conclusion, our findings suggest that decreased GADD45α expression significantly contributes to the development of radioresistance and that ectopic expression of GADD45α sensitizes cervical cancer cells to radiotherapy. GADD45α inhibits the NO-regulated cytoplasmic localization of APE1 through inhibiting eNOS and iNOS, thereby enhancing the radiosensitivity of cervical cancer cells.

The mechanism by which the wild-type KRAS allele imparts a growth inhibitory effect to oncogenic KRAS in various cancers, including lung adenocarcinoma (LUAD), is poorly understood. Here, using a genetically inducible model of KRAS loss of heterozygosity (LOH), we show that KRAS dimerization mediates wild-type KRAS-dependent fitness of human and murine KRAS mutant LUAD tumor cells and underlies resistance to MEK inhibition. These effects are abrogated when wild-type KRAS is replaced by KRAS D154Q , a mutant that disrupts dimerization at the α4-α5 KRAS dimer interface without changing other fundamental biochemical properties of KRAS, both in vitro and in vivo. Moreover, dimerization has a critical role in the oncogenic activity of mutant KRAS. Our studies provide mechanistic and biological insights into the role of KRAS dimerization and highlight a role for disruption of dimerization as a therapeutic strategy for KRAS mutant cancers., (Copyright © 2017 Elsevier Inc. All rights reserved.)

KRAS switch loop movements play a crucial role in regulating RAS signaling, and alteration of these sensitive dynamics is a principal mechanism through which disease-associated RAS mutations lead to aberrant RAS activation. Prior studies suggest that despite a high degree of sequence similarity, the switches in KRAS are more dynamic than those in HRAS. We determined X-ray crystal structures of the rare tumorigenic KRAS mutants KRAS D33E , in switch 1 (SW1), and KRAS A59G , in switch 2 (SW2), bound to GDP and found these adopt nearly identical, open SW1 conformations as well as altered SW2 conformations. KRAS A59G bound to a GTP analogue crystallizes in the same conformation. This open conformation is consistent with the inactive "state 1" previously observed for HRAS bound to GTP. For KRAS A59G , switch rearrangements may be regulated by increased flexibility in the 57 DXXGQ 61 motif at codon 59. However, loss of interactions between side chains at codons 33 and 35 in the SW1 33 DPT 35 motif drives changes for KRAS D33E . The 33 DPT 35 motif is conserved for multiple members of the RAS subfamily but is not found in RAB, RHO, ARF, or Gα families, suggesting that dynamics mediated by this motif may be important for determining the selectivity of RAS-effector interactions. Biochemically, the consequence of altered switch dynamics is the same, showing impaired interaction with the guanine exchange factor SOS and loss of GAP-dependent GTPase activity. However, interactions with the RBD of RAF are preserved. Overall, these observations add to a body of evidence suggesting that HRAS and KRAS show meaningful differences in functionality stemming from differential protein dynamics independent of the hypervariable region.

Importance: Patterns-of-failure studies suggest that in metastatic non-small-cell lung cancer (NSCLC) sites of gross disease at presentation are the first to progress when treated with chemotherapy. This knowledge has led to increased adoption of local ablative radiation therapy in patients with stage IV NSCLC, though prospective randomized evidence is limited., Objective: To determine if intervening with noninvasive stereotactic ablative radiotherapy (SAbR) prior to maintenance chemotherapy in patients with non-progressive limited metastatic NSCLC after induction therapy led to significant improvements in progression-free survival (PFS)., Design, Setting, and Participants: This is a single-institution randomized phase 2 study of maintenance chemotherapy alone vs SAbR followed by maintenance chemotherapy for patients with limited metastatic NSCLC (primary plus up to 5 metastatic sites) whose tumors did not possess EGFR-targetable or ALK-targetable mutations but did achieve a partial response or stable disease after induction chemotherapy., Interventions: Maintenance chemotherapy or SAbR to all sites of gross disease (including SAbR or hypofractionated radiation to the primary) followed by maintenance chemotherapy., Main Outcomes and Measures: The primary end point was PFS; secondary end points included toxic effects, local and distant tumor control, patterns of failure, and overall survival., Results: A total of 29 patients (9 women and 20 men) were enrolled; 14 patients (median [range] age, 63.5 [51.0-78.0] years) were allocated to the SAbR-plus-maintenance chemotherapy arm, and 15 patients (median [range] age, 70.0 [51.0-79.0] years) were allocated to the maintenance chemotherapy-alone arm. The trial was stopped to accrual early after an interim analysis found a significant improvement in PFS in the SAbR-plus-maintenance chemotherapy arm of 9.7 months vs 3.5 months in the maintenance chemotherapy-alone arm (P = .01). Toxic effects were similar in both arms. There were no in-field failures with fewer overall recurrences in the SAbR arm while those patients receiving maintenance therapy alone had progression at existing sites of disease and distantly., Conclusions and Relevance: Consolidative SAbR prior to maintenance chemotherapy appeared beneficial, nearly tripling PFS in patients with limited metastatic NSCLC compared with maintenance chemotherapy alone, with no difference in toxic effects. The irradiation prevented local failures in original disease, the most likely sites of first recurrence. Furthermore, PFS for patients with limited metastatic disease appeared similar to those patients with a greater metastatic burden, further arguing for the potential benefits of local therapy in limited metastatic settings., Trial Registration: clinicaltrials.gov Identifier: NCT02045446.

KRAS G12C, the most common RAS mutation found in non-small-cell lung cancer, has been the subject of multiple recent covalent small-molecule inhibitor campaigns including efforts directed at the guanine nucleotide pocket and separate work focused on an inducible pocket adjacent to the switch motifs. Multiple conformations of switch II have been observed, suggesting that switch II pocket (SIIP) binders may be capable of engaging a range of KRAS conformations. Here we report the use of hydrogen/deuterium-exchange mass spectrometry (HDX MS) to discriminate between conformations of switch II induced by two chemical classes of SIIP binders. We investigated the structural basis for differences in HDX MS using X-ray crystallography and discovered a new SIIP configuration in response to binding of a quinazoline chemotype. These results have implications for structure-guided drug design targeting the RAS SIIP., (Copyright © 2017 Elsevier Ltd. All rights reserved.)