Oncogene Addiction Research Articles

CRISPR/Cas12a-mediated labeling of MET receptor enables quantitative single-molecule imaging of endogenous protein organization and dynamics.

SummarySingle-molecule localization microscopy (SMLM) reports on protein organization in cells with near-molecular resolution and in combination with stoichiometric labeling enables protein counting. Fluorescent proteins allow stoichiometric labeling of cellular proteins; however, most methods either lead to overexpression or are complex and time demanding. We introduce CRISPR/Cas12a for simple and efficient tagging of endogenous proteins with a photoactivatable protein for quantitative SMLM and single-particle tracking. We constructed a HEK293T cell line with the receptor tyrosine kinase MET tagged with mEos4b and demonstrate full functionality. We determine the oligomeric state of MET with quantitative SMLM and find a reorganization from monomeric to dimeric MET upon ligand stimulation. In addition, we measured the mobility of single MET receptors in vivo in resting and ligand-treated cells. The combination of CRISPR/Cas12a-assisted endogenous protein labeling and super-resolution microscopy represents a powerful tool for cell biological research with molecular resolution.

<p>Osimertinib for Front-Line Treatment of Locally Advanced or Metastatic <em>EGFR</em>-Mutant NSCLC Patients: Efficacy, Acquired Resistance and Perspectives for Subsequent Treatments</p>

Non-small cell lung cancer (NSCLC) is one of the most efficient models for precision medicine in oncology. The most appropriate therapeutic for the patient is chosen according to the molecular characteristics of the tumor, schematically distributed between immunogenicity and oncogenic addiction. For this last concept, advanced NSCLC with epidermal growth factor receptor (EGFR) mutation is one of the most illustrative models. EGFR-tyrosine kinase inhibitors (TKIs) are the therapeutic backbone for this type of tumor. The recent development of a third-generation TKI, osimertinib, has been a new step forward in the treatment of NSCLC patients. In this article, we first review the clinical development of osimertinib and highlight its efficacy results. We then present the most frequent tumor escape mechanisms when osimertinib is prescribed in first line: off-target (MET amplification, HER2 amplification, BRAF mutation, gene fusions, histologic transformation) and on-target mechanisms (EGFR mutation). Finally, we discuss subsequent biomarker-driven treatment strategies.

Epigenome engineering: new technologies for precision medicine.

Chromatin adopts different configurations that are regulated by reversible covalent modifications, referred to as epigenetic marks. Epigenetic inhibitors have been approved for clinical use to restore epigenetic aberrations that result in silencing of tumor-suppressor genes, oncogene addictions, and enhancement of immune responses. However, these drugs suffer from major limitations, such as a lack of locus selectivity and potential toxicities. Technological advances have opened a new era of precision molecular medicine to reprogram cellular physiology. The locus-specificity of CRISPR/dCas9/12a to manipulate the epigenome is rapidly becoming a highly promising strategy for personalized medicine. This review focuses on new state-of-the-art epigenome editing approaches to modify the epigenome of neoplasms and other disease models towards a more ‘normal-like state’, having characteristics of normal tissue counterparts. We highlight biomolecular engineering methodologies to assemble, regulate, and deliver multiple epigenetic effectors that maximize the longevity of the therapeutic effect, and we discuss limitations of the platforms such as targeting efficiency and intracellular delivery for future clinical applications.

Serum Lipidome and Glucose Metabolism Uncover Vulnerabilities in Myelodysplasia and Secondary Acute Myelogenous Leukemia

Background Secondary acute myelogenous leukemia (sAML) is highly aggressive and molecularly heterogenous. Previous reports have demonstrated differential serum lipid expression among hemopoietic malignancies (i.e AML, myelodysplastic syndrome (MDS) and acute lymphoblastic leukemia (ALL). Such a distinct serum lipidome among hemopoietic disorders suggest "unique oncogenic metabolic addiction" of leukemia initiating cells (LICs). MDS to AML transition is characterized by clonal evolution [i.e severe aneuploidy, high P53 frequency etc.] and chemorefractoriness. However, mechanism(s) for transformation are not entirely understood. In this study, we investigate serum lipidome and "proxy" of glucose [HbA1C] metabolism among: (1) low risk, (2) high risk MDS and (3) sAML patients (pts) to identify features that may suggest disease specific vulnerabilities. Methods After IRB approval, 214 pts were selected for analysis. ANOVA was used to detect differential expression of total cholesterol (TC), low density lipoprotein (LDL), high-density lipoprotein (HDL), and triglycerides (TAG) among low risk, high risk and sAML pts. Multivariate linear regression model was performed to evaluate the independent effect of confounders on relevant lipid modifications observed among subtypes of MDS and sAML pts. SAS software was used for data processing. Results 69/214 (32.2%), 26/214 (12.1%), 35/214 (16.3%), 35/214 (16.3%), 28/214 (13.08%), 21/214 (9.8%) were sAML, very low (VLR), low (LR), intermediate (I), high (H) and very high risk (VHR) MDS. Median age (range) was 68 y (42-91), 68 y (22-87), 70 y (55-91), 76 (53-88), 72 y (60-85) and 74 y (54-84), for sAML, VLR, LR, I, H and VHR, p=0.0001. In sAML, VLR, LR, I, HR and VHR MDS TC was 177 mg/dL, 150 mg/dL, 126 mg/dL, 134 mg/dL, 125 mg/dL and 122 mg/dL, p=0.0001; LDL was 113.4 mg/dL, 81.3 mg/dL, 67.8 mg/dL, 72 mg/dL, 63.2 mg/dL and 70.8 mg/dL, p=0.0001; HDL 35.8 mg/dL, 39.2 mg/dL, 36.1 mg/dL, 40 mg/dL, 33.7 mg/dL, 32.05 mg/dL, p=0.40; TAG 134 mg/dL, 140 mg/dL, 109 mg/dL, 120 , mg/dL 134 mg/dL, 98 mg/dL, p=0.1. Given "similarities" among MDS subgroups, "MDS lipid data" was compared vs sAML. Median TC, LDL, HDL and TAG among sAML vs MDS pts was 179.1 mg/dL vs 130.4 mg/dL, p=0.0001; 113 mg/dL vs 70.1 mg/dL, p=0.0001; 38.6 mg/dL vs 36.7 mg/dL, p=0.5; 142 mg/dL vs 116.6 mg/dL, p=0.056, respectively. 20/89 (22.7%) vs 69/89 (77.53%) sAML vs MDS pts, respectively were diabetic, p=0.002, OR =2.62; 95% CI 1.40-4.90. However, data extracted from 82 pts (16 sAML and 66 MDS, each) demonstrated that hemoglobin A1C (HbA1C) was 7.84% vs 6.34%, in sAML vs MDS, respectively, p=0.009. Multivariate linear regression accounting for age, blast count, BMI, DM status and HbA1C showed that higher TC, LDL and HbA1C were independent predictors of sAML. Conclusions While this study is restricted to demonstrate distinct lipid and metabolic profile between sAML and MDS, our results suggest blastic phase dependency on higher serum cholesterol and possibly higher advanced glycosylation. As compared to MDS, our data highlights the possibility that sAML induces serum Lipidome modifications that may "hijack endogenous lipogenesis" to favor TC, LDL and possibly TAG production. Additionally, despite larger number of patients is needed to confirm our results, higher HbA1C potentially initiates advanced glycosylation facilitating blastic conversion in MDS pts. Disclosures Rivero: Incyte: Membership on an entity's Board of Directors or advisory committees; agios: Membership on an entity's Board of Directors or advisory committees; celgene: Membership on an entity's Board of Directors or advisory committees.

ERG-Mediated Coregulator Complex Formation Maintains Androgen Receptor Signaling in Prostate Cancer.

The TMPRSS2-ERG fusion is the most common genomic rearrangement in human prostate cancer. However, in established adenocarcinoma, it is unknown how the ERG oncogene promotes a cancerous phenotype and maintains downstream androgen receptor (AR) signaling pathways. In this study, we utilized a murine prostate organoid system to explore the effects of ERG on tumorigenesis and determined the mechanism underlying prostate cancer dependence on ERG. Prostate organoids lacking PTEN and overexpressing ERG (Pten-/- R26-ERG) faithfully recapitulated distinct stages of prostate cancer disease progression. In this model, deletion of ERG significantly dampened AR-dependent gene expression. While ERG was able to reprogram the AR cistrome in the process of prostate carcinogenesis, ERG knockout in established prostate cancer organoids did not drastically alter AR binding, H3K27ac enhancer, or open chromatin profiles at these reprogrammed sites. Proteomic analysis of DNA-bound AR complexes demonstrated that ERG deletion causes a loss of recruitment of critical AR coregulators and basal transcriptional machinery, including NCOA3 and RNA polymerase II, but does not alter AR binding itself. Together, these data reveal a novel mechanism of ERG oncogene addiction in prostate cancer, whereby ERG facilitates AR signaling by maintaining coregulator complexes at AR bound sites across the genome. SIGNIFICANCE: These findings exploit murine organoid models to uncover the mechanism of ERG-mediated tumorigenesis and subsequent oncogenic dependencies in prostate cancer.

The new role for an old guy: MYC as an immunoplayer.

As an oncogene, myelocytomatosis oncogene (MYC) is implicated in the concept of "oncogene addiction," where switching off the oncogene leads to the cell cycle arrest and cell differentiation. However, recent data suggest that MYC also controls the establishment of the tumour microenvironment and that "oncogene addiction" actually has a strong immune background. Evaluation of the MYC role in the immunoediting process led to the speculation that cancer just uses and distorts the physiological mechanism by which MYC normally prevents rapidly proliferating cells from the elicitation of an autoimmune response. Concordantly, elevated levels of MYC and induction of immunosuppressive molecules are observed during the processes of growth and development, tissue repair, placenta development, and so forth, implying that MYC may be involved in saving regular physiologically proliferating cells from the immune system attack. Even more, a growing body of evidence suggests MYC involvement in the shaping of the adaptive immune response, immunological memory development, and establishment of immunotolerance. This paper offers an overview of MYC actions in the context of modulation of the immune response in pathological and physiological conditions. The determination of such a new role for a well-known oncogene opens new perspectives in biomedicine, and consequently, in the treatment of various pathological conditions.

Combination of gefitinib and olaparib versus gefitinib alone in EGFR mutant non-small-cell lung cancer (NSCLC): A multicenter, randomized phase II study (GOAL)

ObjectivesProgression-free survival (PFS) and response rate to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) varies in patients with non-small-cell lung cancer (NSCLC) driven byEGFR mutations, suggesting that other genetic alterations may influence oncogene addiction. Low BRCA1 mRNA levels correlate with longer PFS in erlotinib-treated EGFR-mutant NSCLC patients. Since the poly (ADP-ribose) polymerase (PARP) inhibitor, olaparib, may attenuate and/or prevent BRCA1 expression, the addition of olaparib to gefitinib could improve outcome in EGFR-mutant advanced NSCLC. Materials and methodsGOAL was a multicenter, randomized phase IB/II study performed in two countries, Spain and Mexico. Eligible patients were 18 years or older, treatment-naïve, pathologically confirmed stage IV NSCLC, with centrally confirmed EGFR mutations and measurable disease. Patients were randomly allocated (1:1) to receive gefitinib 250 mg daily or gefitinib 250 mg daily plus olaparib 200 mg three times daily in 28-day cycles. The primary endpoint was PFS. Secondary endpoints included overall survival (OS), response rate, safety and tolerability. ResultsBetween September 2013, and July 2016, 182 patients underwent randomization, 91 received gefitinib and 91 received gefitinib plus olaparib. There were no differences in gender, age, smoking status, performance status, presence of bone and brain metastases or type ofEGFR mutation. Median PFS was 10.9 months (95 % CI 9.3–13.3) in the gefitinib arm and 12.8 months (95 % CI 9.1–14.7) in the gefitinib plus olaparib arm (HR 1.38, 95 % CI 1.00–1.92; p = 0.124). The most common adverse events were anemia, 78 % in gefitinib plus olaparib group, 38 % in gefitinib arm, diarrhea, 65 % and 60 %, and fatigue, 40 % and 32 %, respectively. ConclusionsThe gefitinib plus olaparib combination did not provide significant benefit over gefitinib alone. The combination’s safety profile showed an increase in hematological and gastrointestinal toxicity, compared to gefitinib alone, however, no relevant adverse events were noted.

Traitements systémiques de première ligne dans les CBNPC avancés en l’absence d’addiction oncogénique: Frontline systemic treatment of advanced NSCLC without oncogenic addiction

AbstractFirst-line treatment of metastatic NSCLC without oncogenic addiction was based on chemotherapy regimen combining a platinum salt and a third generation cytotoxic drug, with similar results for the different available schedules. The improvement of chemotherapy results has been limited to non-squamous carcinoma, deriving from maintenance strategies mainly based on continuation of pemetrexed as a single agent and on addition of bevacizumab to chemotherapy. The development of immunotherapy in first-line therapy with anti-PD-1 and anti-PD-L1 has changed the first line treatment algorithm of advanced NSCLC. The anti-PD-1 pembrolizumab clearly improves the overall survival in NSCLC with PD-L1 expression in greater than 50% of tumour cells, comparatively to cytotoxic chemotherapy. Combinations of anti-PD(L)-1 to platinum-based chemotherapy are superior to chemotherapy alone, independently of PD-L1 level of expression. They represent the 1st line gold-standard when PD-L1 is expressed in less than 50% of tumour cells and might reduce the risk of early disease progression in comparison with pembrolizumab when PD-L1 ≥50%. The room for anti-CTLA-4 + anti-PD(L)-1 combinations remains to be established.© 2020 SPLF. Published by Elsevier Masson SAS. All rights reserved.

Oncogenèse pulmonaire : mécanismes généraux et addictions oncogéniques: Pulmonary oncogenesis: General mechanisms and oncogenic addictions

AbstractThe discovery of the molecular alterations at the origin of the cancer process allowed the development of targeted therapies, mainly represented by tyrosine kinase inhibitors. Despite initial efficacy of these treatments, all patients eventually experienced tumor progression caused by systematic emergence of resistance mechanisms. However the growing understanding of the lung cancer biology has led to the design of new inhibitors that can overcome part of these resistance mechanisms. This review describes the concepts of oncogenic addiction and resistance to targeted therapy. It also details the main molecular alterations at the origin of these phenomena in lung cancer.© 2020 SPLF. Published by Elsevier Masson SAS. All rights reserved.

La prise en charge des métastases cérébrales du cancer bronchique: Management of lung cancer brain metastases

AbstractLung cancer is the leading provider of brain metastases (BMs). The prevalence of BMs varies depending on pathology and can occur in up to 50 % of non-small cell lung cancers (NSCLC) and 80 % of small cell lung cancers (SCLC) during follow-up. BMs prevalence is also higher in case of oncogenic addictions such as EGFR mutations or ALK rearrangements. Furthermore, BMs result in significant morbidity and mortality. They are directly responsible for death in 50 % of cases.BMs evolution and response to treatments is heterogeneous, and can be different from the primary tumour. This is due to molecular differences between BMs and primary tumours related to the blood-brain barrier (BBB) but also to a very different tumor microenvironment.Depending on pathology, tumor mutation profile and PDL1 expression, systemic treatments may be based on immunotherapy alone, a combination of chemotherapy and immunotherapy, or targeted therapies. In addition to systemic treatments, local treatments such as surgery, whole brain radiotherapy (WBRT) or stereotactic radiotherapy (SBRT) should be considered. Local treatment choice mainly depends on the number and volume of brain lesions. Because of fewer side effects, SBRT is becoming an increasingly important part of treatment. On the contrary, prophylactic cranial irradiation is limited to SCLCs with good response to chemotherapy.© 2020 SPLF. Published by Elsevier Masson SAS. All rights reserved.

Discovering functional evolutionary dependencies in human cancers.

Cancer cells retain genomic alterations that provide a selective advantage. The prediction and validation of advantageous alterations are major challenges in cancer genomics. Moreover, it is crucial to understand how the coexistence of specific alterations alters response to genetic and therapeutic perturbations. In the present study, we inferred functional alterations and preferentially selected combinations of events in >9,000 human tumors. Using a Bayesian inference framework, we validated computational predictions with high-throughput readouts from genetic and pharmacological screenings on 2,000 cancer cell lines. Mutually exclusive and co-occurring cancer alterations reflected, respectively, functional redundancies able to rescue the phenotype of individual target inhibition, or synergistic interactions, increasing oncogene addiction. Among the top scoring dependencies, co-alteration of the phosphoinositide 3-kinase (PI3K) subunit PIK3CA and the nuclear factor NFE2L2 was a synergistic evolutionary trajectory in squamous cell carcinomas. By integrating computational, experimental and clinical evidence, we provide a framework to study the combinatorial functional effects of cancer genomic alterations.

The lysophospholipase D enzyme Gdpd3 is required to maintain chronic myelogenous leukaemia stem cells

Although advanced lipidomics technology facilitates quantitation of intracellular lipid components, little is known about the regulation of lipid metabolism in cancer cells. Here, we show that disruption of the Gdpd3 gene encoding a lysophospholipase D enzyme significantly decreased self-renewal capacity in murine chronic myelogenous leukaemia (CML) stem cells in vivo. Sophisticated lipidomics analyses revealed that Gdpd3 deficiency reduced levels of certain lysophosphatidic acids (LPAs) and lipid mediators in CML cells. Loss of Gdpd3 also activated AKT/mTORC1 signalling and cell cycle progression while suppressing Foxo3a/β-catenin interaction within CML stem cell nuclei. Strikingly, CML stem cells carrying a hypomorphic mutation of Lgr4/Gpr48, which encodes a leucine-rich repeat (LRR)-containing G-protein coupled receptor (GPCR) acting downstream of Gdpd3, displayed inadequate disease-initiating capacity in vivo. Our data showing that lysophospholipid metabolism is required for CML stem cell maintenance in vivo establish a new, biologically significant mechanism of cancer recurrence that is independent of oncogene addiction.

MCL-1 gains occur with high frequency in lung adenocarcinoma and can be targeted therapeutically

Evasion of programmed cell death represents a critical form of oncogene addiction in cancer cells. Understanding the molecular mechanisms underpinning cancer cell survival despite the oncogenic stress could provide a molecular basis for potential therapeutic interventions. Here we explore the role of pro-survival genes in cancer cell integrity during clonal evolution in non-small cell lung cancer (NSCLC). We identify gains of MCL-1 at high frequency in multiple independent NSCLC cohorts, occurring both clonally and subclonally. Clonal loss of functional TP53 is significantly associated with subclonal gains of MCL-1. In mice, tumour progression is delayed upon pharmacologic or genetic inhibition of MCL-1. These findings reveal that MCL-1 gains occur with high frequency in lung adenocarcinoma and can be targeted therapeutically.

Role of Ubiquitination in PTEN Cellular Homeostasis and Its Implications in GB Drug Resistance.

Glioblastoma (GB) is the most common and aggressive brain malignancy, characterized by heterogeneity and drug resistance. PTEN, a crucial tumor suppressor, exhibits phosphatase-dependent (PI3K-AKT-mTOR pathway)/independent (nucleus stability) activities to maintain the homeostatic regulation of numerous physiological processes. Premature and absolute loss of PTEN activity usually tends to cellular senescence. However, monoallelic loss of PTEN is frequently observed at tumor inception, and absolute loss of PTEN activity also occurs at the late stage of gliomagenesis. Consequently, aberrant PTEN homeostasis, mainly regulated at the post-translational level, renders cells susceptible to tumorigenesis and drug resistance. Ubiquitination-mediated degradation or deregulated intracellular localization of PTEN hijacks cell growth rheostat control for neoplastic remodeling. Functional inactivation of PTEN mediated by the overexpression of ubiquitin ligases (E3s) renders GB cells adaptive to PTEN loss, which confers resistance to EGFR tyrosine kinase inhibitors and immunotherapies. In this review, we discuss how glioma cells develop oncogenic addiction to the E3s-PTEN axis, promoting their growth and proliferation. Antitumor strategies involving PTEN-targeting E3 ligase inhibitors can restore the tumor-suppressive environment. E3 inhibitors collectively reactivate PTEN and may represent next-generation treatment against deadly malignancies such as GB.

1411TiP GFPC 06-2018: A multicenter non-randomized phase II study evaluating platinum-pemetrexed-atezolizumab (+/-bevacizumab) for patients with stage IIIB/IV non-squamous non-small cell lung cancer with EGFR mutations, ALK rearrangement or ROS1 fusion progressing after targeted therapies

For patients (pts) with NSCLC stage IIIB/IV, immuno-checkpoint inhibitors (ICI) have emerged as a standard in first-line setting of pts without oncogenic addiction. Several data suggest a lower efficacy of immunotherapy as single treatment in pts with oncogenic addiction (especially EGFR mutation or ALK/ROS1 rearrangement). Assuming the addition of chemotherapy to immunotherapy may improve the management of patients with oncogenic addiction, we implemented a trial aiming to assess the efficacy of this combination in these subgroups of pts.

C-myc regulates the sensitivity of breast cancer cells to palbociclib via c-myc/miR-29b-3p/CDK6 axis

Palbociclib, a CDK4/6 inhibitor, has been granted accelerated approval by US FDA for hormone receptor-positive HER2-negative metastatic breast cancer. To determine potential biomarkers of palbociclib sensitivity to assist in patient selection and clinical development, we investigated the effects of palbociclib in a panel of molecularly characterized breast cancer cell lines. We quantified palbociclib sensitivity and c-myc expression in 11 breast cancer cell lines, 124 breast cancer samples, and The Cancer Genome Atlas database. We found non-TNBC subtypes were more sensitive to palbociclib than TNBC. Activation of c-myc led to differential palbociclib sensitivities, and further inhibition of c-myc enhanced palbociclib sensitivity. Moreover, we identified for the first time a c-myc/miR-29b-3p/CDK6 axis in breast cancer that could be responsible for c-myc-induced palbociclib insensitivity, in which c-myc activation resulted in downregulation of miR-29b-3p, further activated CDK6 and inhibited cell-cycle arrest at G1 phase. Moreover, downregulated (inactived) c-myc-induced oncogenic addiction could increase palbociclib efficacy, using both Xenograft model and patient-derived tumor xenograft (PDTX) model. Our finding extends the concept of combined blockade of the CDK4/6 and c-myc signaling pathways to increase palbociclib sensitivity, making c-myc a promising biomarker for palbociclib sensitivity in breast cancer.

Addiction to protein kinase C\u0269 due to PRKCI gene amplification can be exploited for an aptamer-based targeted therapy in ovarian cancer

PRKCI, the gene for protein kinase Cι (PKCι), is frequently amplified in ovarian cancer and recent studies have shown that PKCι participates in ovary tumorigenesis. However, it is unknown whether PKCι is differentially involved in the growth/survival between PRKCI-amplified and non-amplified ovarian cancer cells. In this study, we analyzed ovarian cancer patient dataset and revealed that PRKCI is the only PKC family member significantly amplified in ovarian cancer and PRKCI amplification is associated with higher PKCι expression. Using a panel of ovarian cancer cell lines, we found that abundance of PKCι is generally associated with PRKCI amplification. Interestingly, silencing PKCι led to apoptosis in PRKCI-amplified ovarian cancer cells but not in those without PRKCI amplification, thus indicating an oncogenic addiction to PKCɩ in PRKCI-amplified cells. Since small-molecule inhibitors characterized to selectively block atypical PKCs did not offer selectivity nor sensitivity in PRKCI-amplified ovarian cancer cells and were even cytotoxic to non-cancerous ovary surface or fallopian tube epithelial cells, we designed an EpCAM aptamer-PKCι siRNA chimera (EpCAM-siPKCι aptamer). EpCAM-siPKCι aptamer not only effectively induced apoptosis of PRKCI-amplified ovarian cancer cells but also greatly deterred intraperitoneal tumor development in xenograft mouse model. This study has demonstrated a precision medicine-based strategy to target a subset of ovarian cancer that contains PRKCI amplification and shown that the EpCAM aptamer-delivered PKCι siRNA may be used to suppress such tumors.

Abstract 3276: Molecular heterogeneity of anti-PD-1/PD-L1 immunotherapy efficacy is correlated with tumor immune microenvironment in non-small cell lung cancer from East-Asian patients

Abstract Background: Anti-PD-1/PD-L1 immunotherapy is widely used to treat patients with advanced non-small-cell lung cancer (NSCLC). Although PD-1/PD-L1 inhibitor efficacy across NSCLC is now better understood, it is largely unknown how the tumor immune microenvironment differs regarding tumor genomics and its impact on prognosis and response to immunotherapy in East-Asian NSCLC patients. Methods: We performed an integrated analysis on publicly available data to explore associations between anti-PD-1/PD-L1 immunotherapy efficacy and classic driver oncogene mutations, including EGFR, KRAS, and ALK fusion mutations, in East-Asian NSCLC patients. Four pooled and clinical cohort analyses were used to correlate driver oncogene mutation status and tumor microenvironment based on PD-L1 and CD8+ tumor-infiltrating lymphocytes (TILs). Immune infiltrating patterns were also established for genomic NSCLC subgroups by CIBERSORT algorithm. Results: Based on East-Asian NSCLC patients, TIDE analysis revealed that for anti-PD-1/PD-L1 immunotherapy, EGFR-mutant and ALK-rearranged tumors may yield inferior responses; however, KRAS-mutant tumors may respond better. Pooled and clinical cohort analyses demonstrated tumor immune microenvironment heterogeneity with oncogenic addiction. Data showed remarkably higher PD-L1- and TIL-positive KRAS-mutant tumors, suggesting KRAS mutations may drive an inflammatory phenotype with adaptive immune resistance. However, the EGFR-mutant or ALK-rearranged groups showed a remarkably higher proportion of PD-L1−/TIL− tumors, suggesting an uninflamed phenotype with immunological ignorance. Notably, similar to triple wild-type NSCLC, EGFR L858R-mutant tumors positively correlated with an inflammatory phenotype, suggesting responsiveness to anti-PD-1/PD-L1 immunotherapy. Furthermore, CIBERSORT algorithm results revealed that apart from enriched CD8+ T cells, KRAS-mutant NSCLC showed a similar intratumoral immune profile to triple wild-type NSCLC. Strikingly, EGFR-mutant and ALK-rearranged tumors were characterized by enriched resting memory CD4+ T cells, as well as a lack of CD8+ and activated memory CD4+ T cells. Conclusion: Our study highlights the complex relationship between immune heterogeneity and immunotherapeutic response in East-Asian NSCLC patients regarding oncogenic addiction. Importantly, our findings provide support for individualized treatments according to NSCLC molecular subtype. Keywords: NSCLC, East-Asian, oncogene mutations, PD-1/PD-L1 inhibitors, immune landscape Citation Format: Chengming Liu, Runsen Jin, Sufei Zheng, Xinfeng Wang, Nan Sun, Jie He. Molecular heterogeneity of anti-PD-1/PD-L1 immunotherapy efficacy is correlated with tumor immune microenvironment in non-small cell lung cancer from East-Asian patients [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3276.

Abstract NG16: Double PIK3CA mutations in cis increase oncogenicity and sensitivity to PI3Kα inhibitors

Abstract NG16: Double <i>PIK3CA</i> mutations in <i>cis</i> increase oncogenicity and sensitivity to PI3Kα inhibitors

MYC ASO Impedes Tumorigenesis and Elicits Oncogene Addiction in Autochthonous Transgenic Mouse Models of HCC and RCC

The MYC oncogene is dysregulated in most human cancers and hence is an attractive target for cancer therapy. We and others have shown experimentally in conditional transgenic mouse models that suppression of the MYC oncogene is sufficient to induce rapid and sustained tumor regression, a phenomenon known as oncogene addiction. However, it is unclear whether a therapy that targets the MYC oncogene could similarly elicit oncogene addiction. In this study, we report that using antisense oligonucleotides (ASOs) to target and reduce the expression of MYC impedes tumor progression and phenotypically elicits oncogene addiction in transgenic mouse models of MYC-driven primary hepatocellular carcinoma (HCC) and renal cell carcinoma (RCC). Quantitative image analysis of MRI was used to demonstrate the inhibition of HCC and RCC progression. After 4 weeks of drug treatment, tumors had regressed histologically. ASOs depleted MYC mRNA and protein expression in primary tumors in vivo, as demonstrated by real-time PCR and immunohistochemistry. Treatment with MYC ASO in vivo, but not with a control ASO, decreased proliferation, induced apoptosis, increased senescence, and remodeled the tumor microenvironment by recruitment of CD4+ T cells. Importantly, although MYC ASO reduced both mouse Myc and transgenic human MYC, the ASO was not associated with significant toxicity. Lastly, we demonstrate that MYC ASO inhibits the growth of human liver cancer xenografts in vivo. Our results illustrate that targeting MYC expression in vivo using ASO can suppress tumorigenesis by phenotypically eliciting both tumor-intrinsic and microenvironment hallmarks of oncogene addiction. Hence, MYC ASO therapy is a promising strategy to treat MYC-driven human cancers.