Caloric restriction and metformin selectively improved LKB1-mutated NSCLC tumor response to chemo- and chemo-immunotherapy

BACKGROUND

About 10% of NSCLCs are mutated in KRAS and impaired in STK11/LKB1, a genetic background associated with poor prognosis, caused by an increase in metastatic burden and resistance to standard therapy. LKB1 is a protein involved in a number of biological processes and is particularly important for its role in the regulation of cell metabolism. LKB1 alterations lead to protein loss that causes mitochondria and metabolic dysfunction that makes cells unable to respond to metabolic stress. Different studies have shown how it is possible to interfere with cancer metabolism using metformin and caloric restriction (CR) and both modify the tumor microenvironment (TME), stimulating the switch from "cold" to "hot". Given the poor therapeutic response of KRASmut/LKB1mut patients, and the role of LKB1 in cell metabolism, we examined whether the addition of metformin and CR enhanced the response to chemo or chemo-immunotherapy in LKB1 impaired tumors.

METHODS

Mouse cell lines were derived from lung nodules of transgenic mice carrying KRASG12D with either functional LKB1 (KRASG12D/LKB1wt) or mutated LKB1 (KRASG12D/LKB1mut). Once stabilized in vitro, these cell lines were inoculated subcutaneously and intramuscularly into immunocompetent mice. Additionally, a patient-derived xenograft (PDX) model was established by directly implanting tumor fragments from patient into immunocompromised mice. The mice bearing these tumor models were subjected to treatment with chemotherapy or chemo-immunotherapy, both as standalone regimens and in combination with metformin and CR.

RESULTS

Our preclinical results indicate that in NSCLC KRASmut/LKB1mut tumors, metformin and CR do enhance the response to chemo and chemo-immunotherapy, inducing a metabolic stress condition that these tumors are not able to overcome. Analysis of immune infiltrating cells did not bring to light any strong correlation between the TME immune-modulation and the tumor response to metformin and CR.

CONCLUSION

Our in vitro and in vivo preliminary studies confirm our hypothesis that the addition of metformin and CR is able to improve the antitumor activity of chemo and chemoimmunotherapy in LKB1 impaired tumors, exploiting their inability to overcome metabolic stress.

Exploiting endocytosis for transfection of mRNA for cytoplasmatic delivery using cationic gold nanoparticles

Introduction

Gene therapy holds promise to cure various diseases at the fundamental level. For that, efficient carriers are needed for successful gene delivery. Synthetic 'non-viral' vectors, as cationic polymers, are quickly gaining popularity as efficient vectors for transmitting genes. However, they suffer from high toxicity associated with the permeation and poration of the cell membrane. This toxic aspect can be eliminated by nanoconjugation. Still, results suggest that optimising the oligonucleotide complexation, ultimately determined by the size and charge of the nanovector, is not the only barrier to efficient gene delivery.

Methods

We herein develop a comprehensive nanovector catalogue comprising different sizes of Au NPs functionalized with two different cationic molecules and further loaded with mRNA for its delivery inside the cell.

Results and Discussion

Tested nanovectors showed safe and sustained transfection efficiencies over 7 days, where 50 nm Au NPs displayed the highest transfection rates. Remarkably, protein expression was increased when nanovector transfection was performed combined with chloroquine. Cytotoxicity and risk assessment demonstrated that nanovectors are safe, ascribed to lesser cellular damage due to their internalization and delivery via endocytosis. Obtained results may pave the way to design advanced and efficient gene therapies for safely transferring oligonucleotides.

The EU-funded I3LUNG Project: Integrative Science, Intelligent Data Platform for Individualized LUNG Cancer Care With Immunotherapy

Although immunotherapy (IO) has changed the paradigm for the treatment of patients with advanced non-small cell lung cancers (aNSCLC), only around 30% to 50% of treated patients experience a long-term benefit from IO. Furthermore, the identification of the 30 to 50% of patients who respond remains a major challenge, as programmed Death-Ligand 1 (PD-L1) is currently the only biomarker used to predict the outcome of IO in NSCLC patients despite its limited efficacy. Considering the dynamic complexity of the immune system-tumor microenvironment (TME) and its interaction with the host's and patient's behavior, it is unlikely that a single biomarker will accurately predict a patient's outcomes. In this scenario, Artificial Intelligence (AI) and Machine Learning (ML) are becoming essential to the development of powerful decision-making tools that are able to deal with this high-complexity and provide individualized predictions to better match treatments to individual patients and thus improve patient outcomes and reduce the economic burden of aNSCLC on healthcare systems. I³LUNG is an international, multicenter, retrospective and prospective, observational study of patients with aNSCLC treated with IO, entirely funded by European Union (EU) under the Horizon 2020 (H2020) program. Using AI-based tools, the aim of this study is to promote individualized treatment in aNSCLC, with the goals of improving survival and quality of life, minimizing or preventing undue toxicity and promoting efficient resource allocation. The final objective of the project is the construction of a novel, integrated, AI-assisted data storage and elaboration platform to guide IO administration in aNSCLC, ensuring easy access and cost-effective use by healthcare providers and patients.

Isolation and characterization of two newly established thymoma PDXs from two relapses of the same patient: a new tool to investigate thymic malignancies

BACKGROUND

Thymic malignancies are a heterogeneous group of rare cancers for which systemic chemotherapy is the standard treatment in the setting of advanced, recurrent or refractory diseases. Both environmental and genetic risk factors have not been fully clarified and few target-specific drugs have been developed for thymic epithelial tumors. A major challenge in studying thymic epithelial tumors is the lack of preclinical models for translational studies.

MAIN BODY

Starting from bioptic material of two consecutive recurrences of the same patient, we generated two patient-derived xenografts. The patient-derived xenografts models were characterized for histology by immunohistochemistry and mutations using next-generation sequencing. When compared to the original tumors resected from the patient, the two patient-derived xenografts had preserved morphology after the stain with hematoxylin and eosin, although there was a moderate degree of de-differentiation. From a molecular point of view, the two patient-derived xenografts maintained 74.3 and 61.8% of the mutations present in the human tumor of origin.

SHORT CONCLUSION

The newly generated patient-derived xenografts recapitulate both the molecular characteristics and the evolution of the thymoma it derives from well, allowing to address open questions for this rare cancer.

NSCLC Cells Resistance to PI3K/mTOR Inhibitors Is Mediated by Delta-6 Fatty Acid Desaturase (FADS2)

Hyperactivation of the phosphatidylinositol-3-kinase (PI3K) pathway is one of the most common events in human cancers. Several efforts have been made toward the identification of selective PI3K pathway inhibitors. However, the success of these molecules has been partially limited due to unexpected toxicities, the selection of potentially responsive patients, and intrinsic resistance to treatments. Metabolic alterations are intimately linked to drug resistance; altered metabolic pathways can help cancer cells adapt to continuous drug exposure and develop resistant phenotypes. Here we report the metabolic alterations underlying the non-small cell lung cancer (NSCLC) cell lines resistant to the usual PI3K-mTOR inhibitor BEZ235. In this study, we identified that an increased unsaturation degree of lipid species is associated with increased plasma membrane fluidity in cells with the resistant phenotype and that fatty acid desaturase FADS2 mediates the acquisition of chemoresistance. Therefore, new studies focused on reversing drug resistance based on membrane lipid modifications should consider the contribution of desaturase activity.

Present and Future Perspective on PLK1 Inhibition in Cancer Treatment

Polo-like kinase 1 (PLK1) is the principle member of the well conserved serine/threonine kinase family. PLK1 has a key role in the progression of mitosis and recent evidence suggest its important involvement in regulating the G2/M checkpoint, in DNA damage and replication stress response, and in cell death pathways. PLK1 expression is tightly spatially and temporally regulated to ensure its nuclear activation at the late S-phase, until the peak of expression at the G2/M-phase. Recently, new roles of PLK1 have been reported in literature on its implication in the regulation of inflammation and immunological responses. All these biological processes are altered in tumors and, considering that PLK1 is often found overexpressed in several tumor types, its targeting has emerged as a promising anti-cancer therapeutic strategy. In this review, we will summarize the evidence suggesting the role of PLK1 in response to DNA damage, including DNA repair, cell cycle progression, epithelial to mesenchymal transition, cell death pathways and cancer-related immunity. An update of PLK1 inhibitors currently investigated in preclinical and clinical studies, in monotherapy and in combination with existing chemotherapeutic drugs and targeted therapies will be discussed.

Abstract 1539: LKB1 down-modulation by miR-17 biologically and clinically mirrors LKB1-mutated NSCLC

Introduction: In non-small cell lung cancer (NSCLC) LKB1 mutations combined with KRAS hyperactivation define a poor responsive, aggressive and disseminating phenotype. We recently unveiled the vulnerability of KRAS/LKB1 co-mutated (KL) patient-derived xenografts (PDXs) to metabolic stress-based treatments, and a clinical trial to test the efficacy of metformin and fasting-mimicking diet on KL NSCLC is currently ongoing in our Institute. Besides inactivating mutations, LKB1 functionality may be impaired by post-translation regulation. Because miR-17 is a potential epigenetic regulator of LKB1,we hypothesized that wild-type LKB1 (LKB1WT) NSCLC with high miR-17 expression may biologically and clinically mirror LKB1 mutated tumors.

Methods: NSCLC cell lines with different combinations of KRAS mutation and LKB1 deletion were selected, together with a panel of PDXs with high (LKB1WT/miR-17 high) or low (LKB1WT/miR-17 low) miR-17 expression. Taking advantage of series of NSCLC patients and PDXs, we retrospectively evaluated LKB1 and miR-17 expression levels in tumor tissue specimens. In addition, the TCGA dataset was interrogated for miR-17 expression and potential correlation with lung cancer clinical features.

Results: Direct targeting of miR-17 to LKB1 3’UTR was confirmed by luciferase reporter assay. We found that miR-17 overexpression in LKB1WT cell lines functionally impaired the LKB1/AMPK pathway, and prompted apoptotic response to metformin. Of note, LKB1WT/miR-17 high PDXs tumor cells showed a similar behavior upon metformin treatment. A retrospective analysis in patients with NSCLC revealed an inverse correlation between miR-17 and LKB1 expression, and highlighted a prognostic role of miR-17 expression in LKB1WT patients, further confirmed by TCGA data analysis.

Conclusions: We validated miR-17 as epigenetic regulator of LKB1 expression in NSCLC tumors. We propose a miR-17 expression score potentially exploitable to discriminate LKB1WT NSCLC patients with impaired LKB1 expression and poor outcome, eligible for energy-stress-based treatments.

Citation Format: Cristina Borzi, Monica Ganzinelli, Elisa Caiola, Marika Colombo, Giovanni Centonze, Mattia Boeri, Laura Caleca, Ugo Pastorino, Mirko Marabese, Massimo Milione, Massimo Broggini, Marina C. Garassino, Gabriella Sozzi, Massimo Moro. LKB1 down-modulation by miR-17 biologically and clinically mirrors LKB1-mutated NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1539.

Abstract 2380: The effect of metabolic alterations on chemo-immunotherapy response in non-small-cell lung cancer model

Introduction: Lung cancer is one of the leading cause of cancer death worldwide, with an estimate incidence of about 2 million new cases per year. Among all lung cancers, non-small-cell lung cancer (NSCLC) is the most frequent (nearly 85%) with a 5-year survival of about 25% when all stages are considered.NSCLCs are frequently mutated in KRAS or STK11/LKB1 and co-mutation is often reported. Considering the key role of STK11/LKB1 in controlling cell metabolism, we hypothesized that NSCLC harboring mutations in this gene could be vulnerable to metabolic stresses. Different studies in the last years have highlighted how is possible to interfere with cancer metabolism using metformin and caloric restriction.Our work aimed at investigating the role of metabolic stress in determining response to chemotherapy and immunotherapy in LKB1 mutated NSCLC model.

Methods: For isolation of cell lines with the genetic backgrounds, nodules from lungs of KRASG12D/LKB1wt and KRASG12D/LKB1mut transgenic mice were used. Stabilized cell lines were then inoculated intramuscularly in immunocompetent mice and treated with chemotherapy alone (cisplatin) or in combination with metformin and caloric restriction. Caloric restriction consisted of 36 hours of fasting every week for three weeks. Metformin was administered daily for the entire experiment while cisplatin was given once a week for three weeks.

Results: We started our in vivo experiments comparing the response of the tumors characterized by the mutation in KRASG12D or the co-mutation KRASG12D/LKB1mut. The results indicate that the addition of metformin and caloric restriction improve the activity of cisplatin in both tumors but a stronger effect was detected in tumors presenting the deletion of LKB1. In fact, only in the latter group, the effect of the combination lasted beyond the end of the treatment slowing down the tumor growth. The different combinations were well tolerated. Molecular analysis on tumor samples run in parallel are in progress.

Conclusion: Our in vivo preliminary studies confirm our hypothesis that the addition of the caloric restriction and metformin is able to improve the antitumor activity of the cisplatin without increasing the treatment toxicity in tumors characterized by the co-mutations of KRASG12D/LKB1mut. Further investigations are ongoing on the role of metabolic stress in addition to the immunotherapy (using anti PD-1 antibody as immunocheckpoint inhibitor).

Citation Format: Gloriana Ndembe, Mirko Marabese, Ilenia Intini, Alessandra Fabbri, Massimo Moro, Mario Occhipinti, Elisa Sottotetti, Giuseppe Lo Russo, Monica Ganzinelli, Massimo Broggini. The effect of metabolic alterations on chemo-immunotherapy response in non-small-cell lung cancer model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2380.

Abstract 6346: Identification of ERK inhibitor-based combinations targeting LKB1-mutated NSCLC

Background: Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide. It is a very heterogeneous disease where some frequent mutations remain untargetable. Among them there are those affecting STK11/LKB1, the third most commonly mutated gene in NSCLC adenocarcinomas. Patients harboring LKB1-mutated tumors often have a poor prognosis due to the aggressiveness of this type of cancer and the lack of specific and efficacious therapies. Previous studies in our laboratory demonstrated a peculiar in vitro and in vivo activity of ERK inhibitors (ERKi) on LKB1-mutated NSCLC preclinical models. However, due to the huge heterogeneity of this type of tumor, it is likely that ERKi alone will have limited clinical application. In this scenario, the aim of this project is to find ERKi synthetic lethal partners in order to enlarge NSCLC patient population amenable to this therapy.

Methods: We performed high-throughput screenings of a FDA-approved drug library on two different cell line systems (LU99 and H358) each composed by the LKB1 wild-type (wt) parental cell line and the CRISPR-CAS9-derived LKB1 deleted clone. In both the screenings, we treated the cell lines with the FDA-approved library alone or in combination with a subtoxic concentration of the ERKi.

Results: According to our aim, for each screening, we analyzed the results selecting as hits those combinations preferentially active on the LKB1-deleted clones compared to their LKB1-wt cell lines. We verified that the FDA-approved compounds were subtoxic when used as single treatment in both the parental cell lines and their clones. We highlighted 28 and 42 hit combinations for LU99 and H358 isogenic systems, respectively. Some hits were common between the two screenings and the most represented FDA-approved drug’s classes of the hit combinations were PI3K/Akt/mTOR inhibitors, tyrosine kinase receptor inhibitors, MAPK inhibitors and compounds involved in anti-inflammatory pathways neuronal signaling, metabolism and DNA damage. Among the hits, we have cross-validated 4 ERKi-based combinations (a tyrosin kinase inhibitor, a MAPK inhibitor, a serine-threonine selective protein inhibitor and a farnesyl transferase inhibitor) in four different isogenic systems and we are now performing further validation on a panel of NSCLC cell lines with different LKB1-status as well as on NSCLC organoids.

Conclusions: From the FDA-approved drug library screenings, different ERKi-based combinations showed promising results worthy to be deeply studied. Further analyses are ongoing to verify their efficacy on more complex models as NSCLC 3D organoids and to clarify the mechanism of action at the basis of the hit combinations. Positive results could give the chance to develop effective and specific therapies for patient with LKB1-mutated NSCLCs.

Citation Format: Marika Colombo, Matteo Demetrio Tripodi, Gabriel Caso, Elisa Perin, Mirko Marabese, Massimo Broggini, Elisa Caiola. Identification of ERK inhibitor-based combinations targeting LKB1-mutated NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6346.

LKB1: Can We Target an Hidden Target? Focus on NSCLC

LKB1 (liver kinase B1) is a master regulator of several processes such as metabolism, proliferation, cell polarity and immunity. About one third of non-small cell lung cancers (NSCLCs) present LKB1 alterations, which almost invariably lead to protein loss, resulting in the absence of a potential druggable target. In addition, LKB1-null tumors are very aggressive and resistant to chemotherapy, targeted therapies and immune checkpoint inhibitors (ICIs). In this review, we report and comment strategies that exploit peculiar co-vulnerabilities to effectively treat this subgroup of NSCLCs. LKB1 loss leads to an enhanced metabolic avidity, and treatments inducing metabolic stress were successful in inhibiting tumor growth in several preclinical models. Biguanides, by compromising mitochondria and reducing systemic glucose availability, and the glutaminase inhibitor telaglenastat (CB-839), inhibiting glutamate production and reducing carbon intermediates essential for TCA cycle progression, have provided the most interesting results and entered different clinical trials enrolling also LKB1-null NSCLC patients. Nutrient deprivation has been investigated as an alternative therapeutic intervention, giving rise to interesting results exploitable to design specific dietetic regimens able to counteract cancer progression. Other strategies aimed at targeting LKB1-null NSCLCs exploit its pivotal role in modulating cell proliferation and cell invasion. Several inhibitors of LKB1 downstream proteins, such as mTOR, MEK, ERK and SRK/FAK, resulted specifically active on LKB1-mutated preclinical models and, being molecules already in clinical experimentation, could be soon proposed as a specific therapy for these patients. In particular, the rational use in combination of these inhibitors represents a very promising strategy to prevent the activation of collateral pathways and possibly avoid the potential emergence of resistance to these drugs. LKB1-null phenotype has been correlated to ICIs resistance but several studies have already proposed the mechanisms involved and potential interventions. Interestingly, emerging data highlighted that LKB1 alterations represent positive determinants to the new KRAS specific inhibitors response in KRAS co-mutated NSCLCs. In conclusion, the absence of the target did not block the development of treatments able to hit LKB1-mutated NSCLCs acting on several fronts. This will give patients a concrete chance to finally benefit from an effective therapy.

The integrated stress response is tumorigenic and constitutes a therapeutic liability in KRAS-driven lung cancer

The integrated stress response (ISR) is an essential stress-support pathway increasingly recognized as a determinant of tumorigenesis. Here we demonstrate that ISR is pivotal in lung adenocarcinoma (LUAD) development, the most common histological type of lung cancer and a leading cause of cancer death worldwide. Increased phosphorylation of the translation initiation factor eIF2 (p-eIF2α), the focal point of ISR, is related to invasiveness, increased growth, and poor outcome in 928 LUAD patients. Dissection of ISR mechanisms in KRAS-driven lung tumorigenesis in mice demonstrated that p-eIF2α causes the translational repression of dual specificity phosphatase 6 (DUSP6), resulting in increased phosphorylation of the extracellular signal-regulated kinase (p-ERK). Treatments with ISR inhibitors, including a memory-enhancing drug with limited toxicity, provides a suitable therapeutic option for KRAS-driven lung cancer insofar as they substantially reduce tumor growth and prolong mouse survival. Our data provide a rationale for the implementation of ISR-based regimens in LUAD treatment.

The Crossroads between Host Copper Metabolism and Influenza Infection

Three main approaches are used to combat severe viral respiratory infections. The first is preemptive vaccination that blocks infection. Weakened or dead viral particles, as well as genetic constructs carrying viral proteins or information about them, are used as an antigen. However, the viral genome is very evolutionary labile and changes continuously. Second, chemical agents are used during infection and inhibit the function of a number of viral proteins. However, these drugs lose their effectiveness because the virus can rapidly acquire resistance to them. The third is the search for points in the host metabolism the effect on which would suppress the replication of the virus but would not have a significant effect on the metabolism of the host. Here, we consider the possibility of using the copper metabolic system as a target to reduce the severity of influenza infection. This is facilitated by the fact that, in mammals, copper status can be rapidly reduced by silver nanoparticles and restored after their cancellation.

Single-arm, open label prospective trial to assess prediction of the role of ERCC1/XPF complex in the response of advanced NSCLC patients to platinum-based chemotherapy

Background

Platinum-based therapy, combined or not with immune checkpoint inhibitors, represents a front-line choice for patients with non-small-cell lung cancer (NSCLC). Despite the improved outcomes in the last years for this malignancy, only a sub-group of patients have long-term benefit. Excision repair cross-complementation group 1 (ERCC1) has been considered a potential biomarker to predict the outcome of platinum-based chemotherapy in NSCLC. However, the ERCC1 gene is transcribed in four splice variants where the isoform 202 was described as the only one active and able to complex Xeroderma pigmentosum group F-complementing protein (XPF). Here, we prospectively investigated if the active form of ERCC1, as assessed by the ERCC1/XPF complex (ERCC1/XPF), could predict the sensitivity to platinum compounds.

Patients and methods

Prospectively enrolled, patients with advanced NSCLC treated with a first-line regimen containing platinum were centrally evaluated for ERCC1/XPF by a proximity ligation assay. Overall survival (OS), progression-free survival (PFS) and objective response rate (ORR) were analyzed.

Results

The absence of the ERCC1/XPF in the tumor suggested a trend of worst outcomes in terms of both OS [hazard ratio (HR) 1.41, 95% confidence interval (CI) 0.67-2.94, P = 0.373] and PFS (HR 1.61, 95% CI 0.88-3.03, P = 0.123). ORR was marginally influenced in ERCC1/XPF-negative and -positive groups [odds ratio (stable disease + progressive disease versus complete response + partial response) 0.87, 95% CI 0.25-3.07, P = 0.832].

Conclusion

The lack of ERCC1/XPF complex in NSCLC tumor cells might delineate a group of patients with poor outcomes when treated with platinum compounds. ERCC1/XPF absence might well identify patients for whom a different therapeutic approach could be necessary.

•

This is the first study investigating the ERCC1/XPF complex as a platinum-based therapy response biomarker in NSCLC.

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The lack of ERCC1/XPF complex might delineate a group of patients with poor outcomes when treated with platinum compounds.

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ERCC1/XPF absence might identify tumors for whom a different therapeutic approach than platinum compounds could be necessary.

Molecular determinants of response to PI3K/akt/mTOR and KRAS pathways inhibitors in NSCLC cell lines

Despite the impressive results obtained in the preclinical setting, all the inhibitors targeting two central cascades in cancer, the PI3K/akt/mTOR and the KRAS/MEK/ERK pathways, have shown, apart from very few exceptions, disappointing efficacy when translated to the clinic. One of the main reasons of their clinical failure seems to be the lack of a clear molecular determinant of response to these drugs. In this study, we tried to address this point by evaluating the cytotoxic activity of different inhibitors targeting the two pathways at different levels in a panel of ten NSCLC cell lines harboring alterations in PI3K, KRAS or both. We were not able to highlight a correlation between the presence of KRAS and PI3K mutations and a specific sensitivity to the different drugs used. Molecular analyses performed after equimolar treatments showed that, independently from the entity of the response, the drugs are able to modulate the activation of their targets. Interestingly, we found that p53 mutational status separates the cell lines according to their sensitivity to PI3K pathway inhibitors treatments. The alterations considered in the PI3K/akt/mTOR and in the KRAS/MEK/ERK pathways in the different NSCLC cell lines are not sufficient to drive treatment choice but rather p53 status is a potential biomarker for the activity of this class of drugs.

Activity of Birinapant, a SMAC Mimetic Compound, Alone or in Combination in NSCLCs With Different Mutations

Liver kinase B1 (LKB1/STK11) is the second tumor suppressor gene most frequently mutated in non-small-cell lung cancer (NSCLC) and its activity is impaired in about half KRAS-mutated NSCLCs. Nowadays, no effective therapies are available for patients having these mutations. To highlight new vulnerabilities of this subgroup of tumors exploitable to design specific therapies we screened an US FDA-approved drug library using an isogenic system of wild-type (WT) or deleted LKB1. Among eight hit compounds, Birinapant, an inhibitor of the Inhibitor of Apoptosis Proteins (IAPs), was the most active compound in LKB1-deleted clone only compared to its LKB1 WT counterpart. We validated the Birinapant cells response and its mechanism of action to be dependent on LKB1 deletion. Indeed, we demonstrated the ability of this compound to induce apoptosis, through activation of caspases in the LKB1-deleted clone only. Expanding our results, we found that the presence of KRAS mutations could mediate Birinapant resistance in a panel of NSCLC cell lines. The combination of Birinapant with Ralimetinib, inhibitor of p38α, restores the sensitivity of LKB1- and KRAS-mutated cell lines to the IAP inhibitor Birinapant. Our study shows how the use of Birinapant could be a viable therapeutic option for patients with LKB1-mutated NSCLCs. In addition, combination of Birinapant and a KRAS pathway inhibitor, as Ralimetinib, could be useful for patients with LKB1 and KRAS-mutated NSCLC.

Predicting the Role of DNA Polymerase β Alone or with KRAS Mutations in Advanced NSCLC Patients Receiving Platinum-Based Chemotherapy

Clinical data suggest that only a subgroup of non-small cell lung cancer (NSCLC) patients has long-term benefits after front-line platinum-based therapy. We prospectively investigate whether KRAS status and DNA polymerase β expression could help identify patients responding to platinum compounds. Prospectively enrolled, advanced NSCLC patients treated with a first-line regimen containing platinum were genotyped for KRAS and centrally evaluated for DNA polymerase β expression. Overall survival (OS), progression-free survival (PFS), and the objective response rate (ORR) were recorded. Patients with KRAS mutations had worse OS (hazard ratio (HR): 1.37, 95% confidence interval (95% CI): 0.70–2.27). Negative DNA polymerase β staining identified a subgroup with worse OS than patients expressing the protein (HR: 1.43, 95% CI: 0.57–3.57). The addition of KRAS to the analyses further worsened the prognosis of patients with negative DNA polymerase β staining (HR: 1.67, 95% CI: 0.52–5.56). DNA polymerase β did not influence PFS and ORR. KRAS may have a negative role in platinum-based therapy responses in NSCLC, but its impact is limited. DNA polymerase β, when not expressed, might indicate a group of patients with poor outcomes. KRAS mutations in tumors not expressing DNA polymerase β further worsens survival. Therefore, these two biomarkers together might well identify patients for whom alternatives to platinum-based chemotherapy should be used.

Glutaminase Inhibition on NSCLC Depends on Extracellular Alanine Exploitation

Non-small-cell lung cancer (NSCLC) cell lines vary in their sensitivity to glutaminase inhibitors, so it is important to identify the metabolic assets underling their efficacy in cancer cells. Even though specific genetic lesions such as in KRAS and LKB1 have been associated with reliance on glutamine for their metabolic needs, we found no distinction between glutaminase inhibitor CB-839 sensitivity and resistant phenotypes in NSCLC cells with or without these genetic alterations. We demonstrated the close relationship between environmental alanine uptake and catabolism. This response depended on the individual cell’s ability to employ alanine aminotransferase (GPT2) to compensate the reduced glutamate availability. It may, therefore, be useful to determine GPT2 levels to predict which NSCLC patients would benefit most from glutaminase inhibitor treatment.

Lack of Efficacy: When Opioids Do Not Achieve Analgesia from the Beginning of Treatment in Cancer Patients

Introduction

Opioids are often used to relieve moderate to severe pain, but their analgesic response may vary. We focused on the absolute lack of analgesic response immediately after beginning opioid treatment, quantifying the proportion of patients with unchanged or worse pain on day 3 (defined as early non-responders (ENRs)) and day 7.

Methods

This is a post-hoc analysis from a randomized controlled trial involving 498 cancer patients with pain, starting to receive WHO step III opioids. On days 1, 3 and 7 pain intensity (PI) was measured.

Results

On day 3, 68 (13.7%) patients were ENRs, 53 no change and 15 greater PI compared to baseline. The relationships between pain and clinical characteristics showed no significant differences between ENRs and Early responders (ERs), except for PI at baseline, which was significantly lower in ENRs. ENRs on day 3 were re-assessed on day 7 to explore the patterns of analgesic response: 31.7% of patients remained NRs, 48.3% had become responders, and 20.0% were poor responders. Adverse drug reactions were similar in ERs and ENRs at each visit.

Discussion

The complete lack of early response to opioids in cancer patients is clinically important and more frequent than expected. Better definition of the mechanism will allow better pain management in cancer and non-cancer patients.

LKB1 Deficiency Renders NSCLC Cells Sensitive to ERK Inhibitors

INTRODUCTION

Serine/threonine kinase 11 (LKB1/STK11) is one of the most mutated genes in NSCLC accounting for approximately one-third of cases and its activity is impaired in approximately half of KRAS-mutated NSCLC. At present, these patients cannot benefit from any specific therapy.

METHODS

Through CRISPR/Cas9 technology, we systematically deleted LKB1 in both wild-type (WT) and KRAS-mutated human NSCLC cells. By using these isogenic systems together with genetically engineered mouse models we investigated the cell response to ERK inhibitors both in vitro and in vivo.

RESULTS

In all the systems used here, the loss of LKB1 creates vulnerability and renders these cells particularly sensitive to ERK inhibitors both in vitro and in vivo. The same cells expressing a WT LKB1 poorly respond to these drugs. At the molecular level, in the absence of LKB1, ERK inhibitors induced a marked inhibition of p90 ribosomal S6 kinase activation, which in turn abolished S6 protein activation, promoting the cytotoxic effect.

CONCLUSIONS

This work shows that ERK inhibitors are effective in LKB1 and LKB1/KRAS-mutated tumors, thus offering a therapeutic strategy for this prognostically unfavorable subgroup of patients. Because ERK inhibitors are already in clinical development, our findings could be easily translatable to the clinic. Importantly, the lack of effect in cells expressing WT LKB1, predicts that treatment of LKB1-mutated tumors with ERK inhibitors should have a favorable toxicity profile.

Silver Ions as a Tool for Understanding Different Aspects of Copper Metabolism

In humans, copper is an important micronutrient because it is a cofactor of ubiquitous and brain-specific cuproenzymes, as well as a secondary messenger. Failure of the mechanisms supporting copper balance leads to the development of neurodegenerative, oncological, and other severe disorders, whose treatment requires a detailed understanding of copper metabolism. In the body, bioavailable copper exists in two stable oxidation states, Cu(I) and Cu(II), both of which are highly toxic. The toxicity of copper ions is usually overcome by coordinating them with a wide range of ligands. These include the active cuproenzyme centers, copper-binding protein motifs to ensure the safe delivery of copper to its physiological location, and participants in the Cu(I) ↔ Cu(II) redox cycle, in which cellular copper is stored. The use of modern experimental approaches has allowed the overall picture of copper turnover in the cells and the organism to be clarified. However, many aspects of this process remain poorly understood. Some of them can be found out using abiogenic silver ions (Ag(I)), which are isoelectronic to Cu(I). This review covers the physicochemical principles of the ability of Ag(I) to substitute for copper ions in transport proteins and cuproenzyme active sites, the effectiveness of using Ag(I) to study copper routes in the cells and the body, and the limitations associated with Ag(I) remaining stable in only one oxidation state. The use of Ag(I) to restrict copper transport to tumors and the consequences of large-scale use of silver nanoparticles for human health are also discussed.

Exploiting FAsting-mimicking Diet and MEtformin to Improve the Efficacy of Platinum-pemetrexed Chemotherapy in Advanced LKB1-inactivated Lung Adenocarcinoma: The FAME Trial

Advanced lung adenocarcinoma with inactive liver kinase B1 (LKB1) tumor suppressor protein is associated with poor response to immune checkpoint inhibitors and molecularly targeted agents, and with dismal patient prognosis. LKB1 is a central orchestrator of cancer cell metabolism, and halts tumor growth/proliferation during metabolic stress. Recent preclinical evidence suggests that LKB1-inactive lung adenocarcinoma is highly sensitive to metformin, a safe and low-cost antidiabetic compound that inhibits mitochondrial oxidative phosphorylation. The effects of metformin can be enhanced by nutrient deprivation (ie, glucose, amino acids), which reduces intracellular levels of ATP and anabolic precursors and can be achieved by the fasting mimicking diet (FMD). Noticeably, metformin also prevents resistance to cisplatin in preclinical in vitro and in vivo models of LKB1-inactive lung adenocarcinoma. Based on such preclinical evidence, the phase II FAME trial was designed to test the hypothesis that the addition of metformin, with or without cyclic FMD, to standard platinum-based chemotherapy improves the progression-free survival of patients with advanced, LKB-1 inactive lung adenocarcinoma. Enrolled patients will be randomized in a 1:1 ratio to receive cisplatin/carboplatin and pemetrexed with the addition of metformin alone (Arm A) or metformin plus FMD (Arm B). The FAME study will use a "pick-the-winner" design with the aim of establishing which of the 2 experimental treatments is superior in terms of antitumor efficacy and safety. The primary assumption of the study is that the combination of the 2 experimental treatments shall improve median progression-free survival from 7.6 months (historical data with chemotherapy alone) to 12 months. Secondary study endpoints are: objective response rate, overall survival, treatment tolerability, and compliance to the experimental treatment.

Co-occurring KRAS mutation/LKB1 loss in non-small cell lung cancer cells results in enhanced metabolic activity susceptible to caloric restriction: an in vitro integrated multilevel approach

Background

Non–small-cell lung cancer (NSCLC) is a heterogeneous disease, with multiple different oncogenic mutations. Approximately 25–30% of NSCLC patients present KRAS mutations, which confer poor prognosis and high risk of tumor recurrence. About half of NSCLCs with activating KRAS lesions also have deletions or inactivating mutations in the serine/threonine kinase 11 (LKB1) gene. Loss of LKB1 on a KRAS-mutant background may represent a significant source of heterogeneity contributing to poor response to therapy.

Methods

Here, we employed an integrated multilevel proteomics, metabolomics and functional in-vitro approach in NSCLC H1299 isogenic cells to define their metabolic state associated with the presence of different genetic background. Protein levels were obtained by label free and single reaction monitoring (SRM)-based proteomics. The metabolic state was studied coupling targeted and untargeted mass spectrometry (MS) strategy. In vitro metabolic dependencies were evaluated using 2-deoxy glucose (2-DG) treatment or glucose/glutamine nutrient limitation.

Results

Here we demonstrate that co-occurring KRAS mutation/LKB1 loss in NSCLC cells allowed efficient exploitation of glycolysis and oxidative phosphorylation, when compared to cells with each single oncologic genotype. The enhanced metabolic activity rendered the viability of cells with both genetic lesions susceptible towards nutrient limitation.

Conclusions

Co-occurrence of KRAS mutation and LKB1 loss in NSCLC cells induced an enhanced metabolic activity mirrored by a growth rate vulnerability under limited nutrient conditions relative to cells with the single oncogenetic lesions. Our results hint at the possibility that energy stress induced by calorie restriction regimens may sensitize NSCLCs with these co-occurring lesions to cytotoxic chemotherapy.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0954-5) contains supplementary material, which is available to authorized users.

Generation and characterization of MEK and ERK inhibitors- resistant non-small-cells-lung-cancer (NSCLC) cells

BACKGROUND

The RAS/RAF/MEK/ERK pathway is one of the most downregulated pathway in cancer. Inhibitors of RAF and MEK have established clinical use while ERK inhibitors recently faced the clinic. We aimed to generate resistant cell lines which could be helpful for defining new combinations able to overcome resistance.

METHODS

the human NSCLC cell line NCI-H727, sensitive to both MEK and ERK inhibitors, was treated with increasing concentrations of MEK162 (as MEK inhibitor) or SCH772984 as ERK inhibitor.

RESULTS

we successfully obtained a MEK resistant subline (H727/MEK, after 40 passages) as well as an ERK resistant subline (H727/SCH, after 18 passages). The two resistant sublines H727/MEK and H727/SCH were cross-resistant to ERK and MEK inhibitors, respectively, but not to RAF inhibitors. The sublines maintained the responsiveness to inhibitors of the parallel PI3K/akt/mTOR pathway as well as to agents with different mechanism of action. Mechanistically, treatment of sensitive and resistant cells with MEK or ERK inhibitors was able to induce a similar inhibition of ERK phosphorylation, while only in parental cells the drugs were able to induce a downregulation of S6 and RSK phosphorylation.

CONCLUSIONS

these resistant cells represent an important tool for further studies on the mechanisms of resistance and ways to overcome it.

RELEVENT Trial: Phase II Trial of Ramucirumab, Carboplatin, and Paclitaxel in Previously Untreated Thymic Carcinoma/B3 Thymoma With Area of Carcinoma

Thymic epithelial tumors are rare malignancies. Thymic carcinoma represents about 20% of all thymic epithelial tumors and has aggressive behavior, with a greater tendency to metastatic spread. Thymic carcinoma is often diagnosed in advanced stages for which systemic treatment is the main therapeutic option. The association of chemotherapy and antiangiogenic agents in the first-line setting has never been investigated in this very rare cancer. However, preclinical and clinical evidence has suggested that inhibition of angiogenesis could be beneficial. The RELEVENT trial is a multicenter, open-label, single-arm, phase II study aimed at investigating the activity and safety of ramucirumab combined with paclitaxel and carboplatin in chemotherapy-naive patients affected by thymic carcinoma or B3 thymoma with area of carcinoma. The primary endpoint of the trial is the overall response rate. Progression-free survival, overall survival, and safety are secondary endpoints. Patient-reported outcomes will be collected at each visit. The mutational status of a subset of genes, polymorphisms, and selected micro-RNA expression will be evaluated.

RANBP9 affects cancer cells response to genotoxic stress and its overexpression is associated with worse response to platinum in NSCLC patients

Although limited by severe side effects and development of resistance, platinum-based therapies still represent the most common first-line treatment for non-small cell lung cancer (NSCLC). However, a crucial need in the clinical management of NSCLC is represented by the identification of cases sensitive to DNA damage response (DDR)-targeting drugs, such as cisplatin or PARP inhibitors. Here, we provide a molecular rationale for the stratification of NSCLC patients potentially benefitting from platinum compounds based on the expression levels of RANBP9, a recently identified player of the cellular DDR. RANBP9 was found overexpressed by immunohistochemistry (IHC) in NSCLC compared to normal adjacent tissues (NATs) (n = 147). Moreover, a retrospective analysis of 132 platinum-treated patients from the multi-centric TAILOR trial showed that RANBP9 overexpression levels are associated with clinical response to platinum compounds [Progression Free Survival Hazard Ratio _{(RANBP9 high vs low)} 1.73, 95% CI 1.15-2.59, p = 0.0084; Overall Survival HR _{(RANBP9 high vs low)} 1.99, 95% CI 1.27-3.11, p = 0.003]. Accordingly, RANBP9 KO cells showed higher sensitivity to cisplatin in comparison with WT controls both in vitro and in vivo models. NSCLC RANBP9 KO cells were also more sensitive than control cells to the PARP inhibitor olaparib alone and in combination with cisplatin, due to defective ATM-dependent and hyper-activated PARP-dependent DDR. The current investigation paves the way to prospective studies to assess the clinical value of RANBP9 protein levels as prognostic and predictive biomarker of response to DDR-targeting drugs, leading to the development of new tools for the management of NSCLC patients.

Therapeutic potential of combined BRAF/MEK blockade in BRAF-wild type preclinical tumor models

Background

Mounting evidence suggests that RAF-mediated MEK activation plays a crucial role in paradox MAPK (re)activation, leading to resistance and therapeutic failure with agents hitting a single step along the MAPK cascade.

Methods

We examined the molecular and functional effects of single and combined BRAF (dabrafenib), pan-RAF (RAF265), MEK (trametinib) and EGFR/HER2 (lapatinib) inhibition, using Western Blot and conservative isobologram analysis to assess functional synergism, and explored genetic determinants of synergistic interactions. Immunoprecipitation based assays were used to detect the interaction between BRAF and CRAF. The Mann-Whitney U test was used for comparing quantitative variables.

Results

Here we demonstrated that a combination of MEK and BRAF inhibitors overcomes paradoxical MAPK activation (induced by BRAF inhibitors) in BRAF-wt/RAS-mut NSCLC and PDAC in vitro. This results in growth inhibitory synergism, both in vitro and in vivo, in the majority (65%) of the cellular models analyzed, encompassing cell lines and patient-derived cancer stem cells and organoids. However, RAS mutational status is not the sole determinant of functional synergism between RAF and MEK inhibitors, as demonstrated in KRAS isogenic tumor cell line models. Moreover, in EGFR-driven contexts, paradoxical MAPK (re)activation in response to selective BRAF inhibition was dependent on EGFR family signaling and could be offset by simultaneous EGFR/HER-2 blockade.

Conclusions

Overall, our data indicate that RAF inhibition-induced paradoxical MAPK activation could be exploited for therapeutic purposes by simultaneously targeting both RAF and MEK (and potentially EGFR family members) in appropriate molecular contexts. KRAS mutation per se does not effectively predict therapeutic synergism and other biomarkers need to be developed to identify patients potentially deriving benefit from combined BRAF/MEK targeting.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0820-5) contains supplementary material, which is available to authorized users.

Abstract LB-245: Multiple DNA-damage response pathways are modulated by RANBP9 protein in NSCLC

Non-small cell lung cancer (NSCLC) is the most prominent cause of cancer-related deaths in the world. The most indicated treatment for over 50% of NSCLC patients is represented by platinum-based chemotherapy. These compounds exert their biological effects by inducing DNA damages. Differently from normal cells, cancer cells frequently display a defective DNA Damage Response (DDR), which results in cancer cell death upon treatment with DNA-damaging agents. However, cancer cells up-regulate specific DDR mechanisms to cope with genotoxic stress, leading to resistance to conventional chemotherapies. For these reasons, a better understanding of cellular DDR mechanisms in tumors might help to identify 1) biomarkers predictive of DNA-repair defects and 2) targeted agents to inhibit tumor specific DNA-repair pathways. We have previously demonstrated that RANBP9 is a new phosphorylation target and signaling facilitator of ATM, one of the most important kinases in DDR. We have recently shown that RANBP9 is upregulated in lung cancer vs normal adjacent tissues, and its protein levels correlate with tumor stage. Importantly, low RANBP9 levels were associated to enhanced progression free survival and overall survival upon treatment with platinum-based compounds, in a cohort of more than 130 NSCLC patients. To gain molecular insights in the role of RANBP9 in DDR and sensitivity to genotoxic stress, we generated NSCLC cell lines where its expression was abrogated by CRISPR/Cas9. These models confirmed that absence of RANBP9 results in enhanced therapeutic effects of cisplatin and reduced activation of ATM-dependent DDR. Notably, we also observed that RANBP9 abrogation resulted in increased levels of polyADP-ribosylated chromatin proteins, without affecting total levels of poly(ADP-ribose) polymerase 1 (PARP1), another critical mediator of DDR. Conversely, we found reduced levels of PAR-glycohydrolase (PARG), a negative regulator of nuclear PAR levels, in response DNA-damaging agents. Based on these results, we hypothesized that RANBP9 levels could dictate the preferential DDR mechanism activated by lung cancer cells in response to genotoxic stress. Accordingly, preliminary evidences show that RANBP9-negative cells (PARP-dependent) display higher sensitivity to PARP inhibition. On the other hand, RANBP9-positive cells (ATM-dependent) are more sensitive to ATM inhbition. In summary, our study suggests that RANBP9 could act both as a positive and as a negative regulator of different mechanisms of DDR. These findings pave the way to clinical studies where RANBP9 levels could be used to inform the choice of the most effective genotoxic therapy and prevent resistance.

Citation Format: Anna Tessari, Kareesma Parbhoo, Meghan Pawlikowski, Matteo Fassan, Eliana Rulli, Claudia Foray, Alessandra Fabbri, Valerio Embrione, Monica Ganzinelli, Marina Capece, Massimo Broggini, Gabriella Farina, Mirko Marabese, Marina C. Garassino, Carlo Croce, Dario Palmieri, Vincenzo Coppola. Multiple DNA-damage response pathways are modulated by RANBP9 protein in NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-245.

Different metabolic responses to PI3K inhibition in NSCLC cells harboring wild-type and G12C mutant KRAS

KRAS mutations in non-small-cell lung cancer (NSCLC) patients are considered a negative predictive factor and indicate poor response to anticancer treatments. KRAS mutations lead to activation of the PI3K/akt/mTOR pathway, whose inhibition remains a challenging clinical target. Since the PI3K/akt/mTOR pathway and KRAS oncogene mutations all have roles in cancer cell metabolism, we investigated whether the activity of PI3K/akt/mTOR inhibitors (BEZ235 and BKM120) in cells harboring different KRAS status is related to their metabolic effect. Isogenic NSCLC cell clones expressing wild-type (WT) and mutated (G12C) KRAS were used to determine the response to BEZ235 and BKM120. Metabolomics analysis indicated the impairment of glutamine in KRAS-G12C and serine metabolism in KRAS-WT, after pharmacological blockade of the PI3K signaling, although the net effect on cell growth, cell cycle distribution and caspase activation was similar. PI3K inhibitors caused autophagy in KRAS-WT, but not in KRAS-G12C, where there was a striking decrease in ammonia production, probably a consequence of glutamine metabolism impairment.

These findings lay the grounds for more effective therapeutic combinations possibly distinguishing wild-type and mutated KRAS cancer cells in NSCLC, exploiting their different metabolic responses to PI3K/akt/mTOR inhibitors.

Wee1 inhibitor MK1775 sensitizes KRAS mutated NSCLC cells to sorafenib

Non-Small-Cell Lung Cancer (NSCLC) is a poorly chemosensitive tumor and targeted therapies are only used for about 15% of patients where a specific driving and druggable lesion is observed (EGFR, ALK, ROS). KRAS is one of the most frequently mutated genes in NSCLC and patients harboring these mutations do not benefit from specific treatments. Sorafenib, a multi-target tyrosine kinase inhibitor, was proposed as a potentially active drug in KRAS-mutated NSCLC patients, but clinical trials results were not conclusive. Here we show that the NSCLC cells’ response to sorafenib depends on the type of KRAS mutation. KRAS G12V cells respond less to sorafenib than the wild-type counterpart, in vitro and in vivo. To overcome this resistance, we used high-throughput screening with a siRNA library directed against 719 human kinases, and Wee1 was selected as a sorafenib response modulator. Inhibition of Wee1 by its specific inhibitor MK1775 in combination with sorafenib restored the KRAS mutated cells’ response to the multi-target tyrosine kinase inhibitor. This combination of the Wee1 inhibitor with sorafenib, if confirmed in models with different genetic backgrounds, might be worth investigating further as a new strategy for KRAS mutated NSCLC.

Abstract A112: RanBP9 protects cells from genotoxic stress and increased expression is predictive of worse response to platinum in NSCLC patients

Platinum-based therapies currently represent the most common first-line treatment for non-small cell lung cancer (NSCLC). The efficacy of platinum compounds depends on the activation of the cellular DNA damage response (DDR), which leads to cancer cell death. However, severe toxic effects and development of resistance represent major limitations in the use of these drugs. Thus, a better mechanistic understanding and new prognostic and predictive biomarkers of the DDR are required to improve outcomes of NSCLC treatment. We have previously reported that RanBP9 (Palmieri et al., 2016), a poorly characterized scaffold protein, participates in the DDR and that its downregulation causes enhanced sensitivity to DNA damage induced by ionizing radiation. In the present study, we used immunohistochemical analysis to reveal that RanBP9 expression is significantly and commonly elevated in 178 lung tumors of different histotypes compared to their normal adjacent tissue (p<0.02 - 0.001). We also show that knockout (KO) of RanBP9 in A549 NSCLC cell lines resulted in reduced DDR and higher levels of cisplatin-induced apoptosis both in vitro and in vivo. These findings were validated by a retrospective analysis of 134 NSCLC patients in which higher levels of RanBP9 associated with tumor stage (p<0.0001), and poor response to platinum compounds as first-line treatment (PFS, HR (RanBP9 positive vs negative) 1.71, 95% CI 1.142 - 2.563, p = 0.0093). Finally, we show that ablation of RanBP9 is associated with overactivation of poly(ADP-ribose) polymerase (PARP) and increased cisplatin antineoplastic efficacy in combination with PARP inhibitors, indicating that the absence of RanBP9 results in a BRCAness-like phenotype. Overall, these results reveal that RanBP9 is a novel predictive biomarker of response to genotoxic treatments in NSCLC, paving the way to prospective studies aimed at assessing its clinical prognostic value and therapeutic targeting.

Citation Format: Anna Tessari, Kareesma Parbhoo, Meghan Pawlikowski, Matteo Fassan, Eliana Rulli, Claudia Foray, Alessandra Fabbri, Valerio Embrione, Monica Ganzinelli, Marina Capece, Moray J. Campbell, Massimo Broggini, Krista La Perle, Gabriella Farina, Sara Cole, Mirko Marabese, Joseph M. Amann, David P. Carbone, Marina C. Garassino, Carlo M. Croce, Dario Palmieri, Vincenzo Coppola. RanBP9 protects cells from genotoxic stress and increased expression is predictive of worse response to platinum in NSCLC patients [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A112.

PQR309 Is a Novel Dual PI3K/mTOR Inhibitor with Preclinical Antitumor Activity in Lymphomas as a Single Agent and in Combination Therapy

Purpose: Activation of the PI3K/mTOR signaling pathway is recurrent in different lymphoma types, and pharmacologic inhibition of the PI3K/mTOR pathway has shown activity in lymphoma patients. Here, we extensively characterized the in vitro and in vivo activity and the mechanism of action of PQR309 (bimiralisib), a novel oral selective dual PI3K/mTOR inhibitor under clinical evaluation, in preclinical lymphoma models.Experimental Design: This study included preclinical in vitro activity screening on a large panel of cell lines, both as single agent and in combination, validation experiments on in vivo models and primary cells, proteomics and gene-expression profiling, and comparison with other signaling inhibitors.Results: PQR309 had in vitro antilymphoma activity as single agent and in combination with venetoclax, panobinostat, ibrutinib, lenalidomide, ARV-825, marizomib, and rituximab. Sensitivity to PQR309 was associated with specific baseline gene-expression features, such as high expression of transcripts coding for the BCR pathway. Combining proteomics and RNA profiling, we identified the different contribution of PQR309-induced protein phosphorylation and gene expression changes to the drug mechanism of action. Gene-expression signatures induced by PQR309 and by other signaling inhibitors largely overlapped. PQR309 showed activity in cells with primary or secondary resistance to idelalisib.Conclusions: On the basis of these results, PQR309 appeared as a novel and promising compound that is worth developing in the lymphoma setting. Clin Cancer Res; 24(1); 120-9. ©2017 AACR.

Abstract 760: Detection of EGFR T790M mutation by ddPCR in untreated NSCLC patients: Correlation with clinical outcome

Background: Activating EGFR mutations are associated with response to first generation tyrosine kinase inhibitors (TKI) that significantly increased PFS and OS in NSCLC patients. However, almost invariably, patients relapse while in treatment with TKI, mostly for the presence of EGFR T790M mutation. New second and third generation EGFR inhibitors active against T790M are now under development with very promising results. To date it is not known if the presence of T790M (and its amount) at diagnosis influences clinical outcome of patients with activating EGFR mutation.

Methods: We analysed 50 cases with NSCLC. 48 patients harbour TKI sensitizing mutation in either exon 19 (N=24) or 21 (N=19). 2 EGFR wt patients (blinded to the investigator) were analysed in parallel. These patients were screened by ddPCR for the presence of T790M mutation using Biorad QX200 Droplet Digital PCR System. We used rough DNA extract from FFPE sections after deparaffinization and proteinase K digestion, as available in pathology unit for daily diagnosis.

Results: 12 samples failed to amplify, maybe due to the poor quality of DNA. 13 samples produced results, but were excluded for the analysis because of too low number of calls retrieved. T790M mutation was detected in a significant proportion of remaining cases. Among the latter, 4 patients were sampled after TKI treatment and here the percentage of T790M were higher compared to those patients not treated [0.65% - 28% vs 0.019% - 1.65%, respectively]. One out four of these patients was not detected by routinely method of sequencing (Sanger or RT-PCR). T790M positive samples harboured mutations affecting exon 19 or 21 in equal manner.

Conclusions: ddPCR has proven to be a sensitive method to detect T790M mutation, although the quality of DNA could affect the results. The system has been challenged for specificity an sensitivity and the results proved to be clinically relevant. The correlation between the T790M positivity and clinical outcome will be available and we plan to define a ddPCR threshold value which can help in selecting those patients who are likely to have early recurrence under first generation TKI and that could therefore be directly shifted to second or third generation inhibitors.

Citation Format: Monica Ganzinelli, Eliana Rulli, Elena Tamborini, Adele Busico, Giuseppe Lo Russo, Giulia Corrao, Milena Vitali, Marina Chiara Garassino, Massimo Broggini, Mirko Marabese. Detection of EGFR T790M mutation by ddPCR in untreated NSCLC patients: Correlation with clinical outcome [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 760. doi:10.1158/1538-7445.AM2017-760

Abstract 2352: Effect of inhibition of cell cycle versus transcription cyclin-dependent kinases (CDKs) in ovarian cancer cells

Background. Cell cycle is regulated by cyclin-dependent kinases (CDKs) activity, whose deregulation can lead to uncontrolled proliferation and cancer. Other CDKs are engaged in the regulation of transcription and post-transcriptional mRNA processing through the phosphorylation of the C-terminal domain of RNA polymerase II, such as CDK9 and CDK12. Inhibitors of cell cycle CDKs have been developed as anticancer agents and some of them are under clinical validation (e.g. palbociclib). While recent data would suggest that inhibition of CDK9 is feasible and has antitumor effect, the data on the therapeutic role of CDK12 inhibition are very scanty.

Methods. Ovarian cancer cell lines were maintained in RPMI medium supplemented with 5% glutamine and 10% FBS. Cells were treated with different drug concentrations and after 72 hours cell survival was evaluated by MTS assay (Promega). IC50 values were calculated by interpolation method. Cell cycle analysis and apoptosis were performed with standard flow cytometric methods. A2780 and SKOV3 ovarian cancer cell lines knocked out for CDK12 were generated with CRISPR/CAS9 genome editing tool.

Results. The cytotoxicity of palbociclib (a CDK4/6 inhibitor) and LDC000067 (a CDK9 inhibitor) was tested in a panel of ovarian cancer cell lines (A2780, SKOV3, OVCAR3, OVCAR5, OVCAR8, OVCA432, OVCA433, IGROV1, EFO27). Sensitivity of cells was similar for palbociclib and LDC000067, ranging from 10 to 33 and from 8 to 60 μM, respectively. A preferential G1 block was observed with palbociclib, while LDC000067 caused a S-G2 block. A higher induction of apoptosis was observed after LDC000067 than after palbociclib treatment in both A2780 and SKOV3. The palbociclib-induced G1 block was associated with decreased Rb phosphorylation, while no modulation of the Ser2 in the carboxyterminal domain of RNA polymerase II was observed after LDC000067 treatment. We generated CDK12 knocked out cells transfecting CRISPR/CAS9 engineered plasmid in both A2780 and SKOV3 ovarian cancer lines. The biological and pharmacological characterization of these clones is under study.

Conclusions. Palbociclib and LDC000067 showed a dose dependent cytotoxic effect in the panel of ovarian cancer cell lines tested and were active in the μM range. Preliminary data of treatment induced cell cycle perturbation and apoptosis suggest that the two drugs behave in a different manner and have distinct molecular effects on cells.

Citation Format: Rosaria Chilà, Nicolò Panini, Eugenio Erba, Giovanna Damia, Massimo Broggini. Effect of inhibition of cell cycle versus transcription cyclin-dependent kinases (CDKs) in ovarian cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2352. doi:10.1158/1538-7445.AM2017-2352

Abstract 174: Preclinical activity of new liposomal formulation of doxorubicin (TLD-1)

Background: InnoMedica is a young company with focus on clinical translation of nanomedicine. The company employs its own manufacturing technology that gives rise to a novel liposome platform. The platform allows for specific shaping of nanosurfaces. This leads to a myriad of different particle designs with highly distinct biological functions. In a first approach, the lead-formulation TLD-1 (targeted liposomal doxorubicin) was developed in order to ameliorate chemotherapeutic outcome for patients, taking into account the patterns of biodistribution in the entire organism as well as nanoparticle-cell interactions and subcellular localisation.

Methods: Pharmacologic properties of TLD-1 were investigated in vitro and in vivo. Human ovarian cancer cells A2780 were cultured in both 2D and 3D settings and antineoplastic activity of different formulations of doxorubicin was measured by quantification of cell viability. The same formulations were also compared in three animal models of cancer including murine breast cancer 4T1, human breast cancer MDA-MB231, and A2780. MDA-MB231 and A2780 cells were grown in vitro and injected subcutaneously (sc) in immunodeficient mice (Athymic Nude-Foxn1nu). 4T1 cells were injected either sc or in the mammary fat pad of immunocompetent mice (BALB/c). The different drug products were injected intravenously twice weekly for a total of three weeks. Activity was determined with caliper measurements of tumor diameters every three days. Animal body weight was recorded as index of toxicity. Doxorubicin was determined in plasma and tissues by HPLC-MS.

Results: In 2D and 3D cell culture assays, TLD-1 showed a marked increase in cytotoxicity compared to Caelyx and was close to free drug. In all three animal models, TLD-1 showed activity superior to that of free doxorubicin given at the same dose and compared well to Caelyx both in terms of activity and toxicity.

Conclusions: A couple of nanoparticulate features of TLD-1 liposomes are believed to attribute to the difference in antitumor activity. Cytotoxicity data from cell culture experiments indicate that TLD-1 liposomes are readily taken up by cancer cells and release their drug load into the cytoplasm. Commercial liposomes as in Caelyx seem to largely remain outside of cancer cells. In sum, TLD-1 is a novel and highly active antineoplastic nanodrug that has the potential to outperform free drug as well as commercial liposomal formulations of doxorubicin.

Citation Format: Massimo Broggini, Federica Guffanti, Roberta Affatato, Lavinia Morosi, Patrick Buschor, Christoph Matthieu, Florian Weiss, Andreas Konig, Peter Halbherr, Stefan Halbherr. Preclinical activity of new liposomal formulation of doxorubicin (TLD-1) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 174. doi:10.1158/1538-7445.AM2017-174

Abstract 508: DNA repair status in a patient derived ovarian cancer xenobank

Epithelial ovarian cancer (EOC) is the most lethal gynecological malignancy with a 5-year relative survival rate of 45%. The high mortality rate is in part due to the development of platinum chemoresistance occurring in more than 70% of patients after the first-line therapy. DNA repair capacity has been reported to be a key determinant for the cellular response to platinum agents. Since half of the high grade serous EOCs lacks Homologous Recombination repair, we aimed to profile the DNA repair status in a panel of well characterized 42 ovarian patient derived xenografts (PDXs) recently established in our laboratory and to correlate it with the in vivo response to a platinum based therapy. We evaluated by real time PCR (ABI-7900, Applied Biosystems) the mRNA levels of genes with a key role in Base Excision Repair (OGG1, POLB and PARP1), Homologous Recombination (BRCA1, PALB2, TP53BP1 and RAD51), Nucleotide Excision Repair (ERCC1, XPA, XPF, XPD and XPG), Fanconi Anemia pathway (FANCA, FANCC, FANCD2 and FANCF), Translesion Repair (POLEta), Mismatch Repair (MLH1), Microhomology End Joining (POLQ), Non Homologous End Joining (XRCC4, XRCC5, XRCC6 and XRCC7) and CDK12, a kinase regulating the transcription of some DNA repair genes. The methylation status of BRCA1, ERCC1, MLH1, XPA, XPG and FANCF was investigated by standard techniques. Our results show that the DNA repair genes considered were variably expressed in all the 42 PDXs analyzed, with no specific histotype-specific cluster of expression. The expression of PALB2, FANCC, FANCD2, OGG1, POLQ and RAD51 was found to correlate with the expression of at least six other genes. In high grade serous/endometrioid PDXs, the CDK12 mRNA expression levels positively correlated with the expression of TP53BP1, PALB2, XPF and POLB. BRCA1 was found to be hypermethylated in 51% of the xenografts. TP53 mutated PDXs showed statistically significant higher levels of POLQ, FANCD2, RAD51, and POLB genes. The expression of CDK12 [p=0.017], PALB2 [p=0.019] and XPF [p= 0.016] was negatively associated with the in vivo response to DDP, with resistant PDXs showing higher mRNA levels than responsive ones. We looked for association with overall survival in the TCGA data set and we found that high levels of CDK12 were associated with a worse overall survival in patients with a residual tumor after surgery minus than 2cm. These data suggest that some DNA repair genes can have a role in EOC patients’ response to DDP therapy. Particularly, CDK12 was significantly able to predict worse survival in patients undergoing optimal debulking surgery. Our xenobank will be a valid instrument to set up functional DNA repair assays, as suggested by preliminary data on primary cultures.

Citation Format: Federica Guffanti, Maddalena Fratelli, Monica Ganzinelli, Francesca Ricci, Roberta Affatato, Maria Rosa Cappelletti, Daniele Generali, Francesca Bizzaro, Massimo Broggini, Raffaella Giavazzi, Giovanna Damia. DNA repair status in a patient derived ovarian cancer xenobank [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 508. doi:10.1158/1538-7445.AM2017-508

Combination of paclitaxel, bevacizumab and MEK162 in second line treatment in platinum-relapsing patient derived ovarian cancer xenografts

Advanced ovarian cancer is very responsive to first line platinum therapy, however almost invariably it relapses with a resistant disease. We have reported that patient derived ovarian xenografts (PDXs), independently from the degree of the initial response to cisplatin (DDP), show a significantly lower response to a second DDP cycle. We here report the effect of new combination regimens containing a MEK inhibitor (MEK), bevacizumab (BEV) and paclitaxel (PTX) as second line therapy in platinum-relapsing PDXs.

We selected three DDP-relapsing PDX models based on the presence of activation of the RAS/RAF/MEK/ERK axis, mutated p53, lack of PTEN expression and activation of the PI3K pathway. In all the selected xenograft models, the antitumor efficacy of the doublets can be summarized as PTX/BEV > BEV/MEK > PTX/MEK and the antitumor activity of the triple combination was higher than any double combination. All the different combinations were well tolerated. The present data corroborate the activity of bevacizumab in combination with chemotherapy for the treatment of relapsing ovarian tumors and suggest that the addition of another targeted agents (MEK inhibitor) can further increase the antitumor activity without any increase in toxicity. PDX models represent a useful model to test second line therapy after failure of DDP first line.

Co-existance of KRAS and LKB1 mutation as predictor of resistance to Erlotinib: Customized next-generation sequencing (NGS) of TAILOR trial

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Background: The prognostic and predictive value of KRAS mutation in advanced NSCLC is still debatable. In TAILOR (NCT00637910) trial EGFR wild-type patients were randomized to receive 2nd line erlotinib versus docetaxel, and no interaction was detected according to KRAS mutational status. Recent evidences indicate that the concurrent mutation of KRAS and LKB1 (key factor for cell metabolism) may be associated with worse prognosis. Methods: Availableformalin-fixed embeddedtissue samples with annotated clinical data from TAILOR were gathered. Customized deep sequencing (Ion proton Technology) of 111 genes most frequently associated with cancer, was performed; 5% of frequency was used to identify mutations. Association between genes and clinical features was performed with non-parametric tests; Cox regression analysis was used to assess the prognostic and predictive value of LKB1. Results: 123 out of 222 (55%) randomized patients had available tissue and were successfully sequenced. 42/123 (34%) patients had a KRAS mutation. KRAS and LKB1 mutations were found in 11/42 (26%) KRAS patients, while only 6 patients had a LKB1 mutation without KRAS. The presence of a concurrent KRAS-LKB1 mutation did not adversely influence progression-free (PFS) or overall (OS) survival [hazard ratio (HR) PFS 1.08, 95% confidence interval (CI) 0.57-2.05, P = 0.81; OS 1.09, 95% CI 0.56-2.14, P = 0.78]. Patients receiving docetaxel experienced longer survival regardless of the KRAS-LKB1 mutational status (mutated KRAS-LKB1 HR 0.42, 95% CI 0.08-2.29; wild-type KRAS-LKB1 HR 1.16, 95% CI 0.72-1.87, P = 0.55; interaction P = 0.10). Conclusions: Although the significant attrition and the limited number, these data generate the hypothesis that the concurrent mutation of KRAS and LKB1 may potentially be associated with resistance to erlotinib. Overall, the coexistence of mutation in KRAS and LKB1 is not associated with worse prognosis in NSCLC. For these patients refractory to EGFR targeting, metabolic strategies represent a future research opportunity.

Class II phosphoinositide 3-kinase C2β regulates a novel signaling pathway involved in breast cancer progression

It is now well established that the enzymes phosphoinositide 3-kinases (PI3Ks) have a key role in the development and progression of many cancer types and indeed PI3Ks inhibitors are currently being tested in clinical trials. Although eight distinct PI3K isoforms exist, grouped into three classes, most of the evidence currently available are focused on one specific isoform with very little known about the potential role of the other members of this family in cancer. Here we demonstrate that the class II enzyme PI3K-C2β is overexpressed in several human breast cancer cell lines and in human breast cancer specimens. Our data indicate that PI3K-C2β regulates breast cancer cell growth in vitro and in vivo and that PI3K-C2β expression in breast tissues is correlated with the proliferative status of the tumor. Specifically we show that downregulation of PI3K-C2β in breast cancer cell lines reduces colony formation, induces cell cycle arrest and inhibits tumor growth, in particular in an estrogen-dependent in vivo xenograft. Investigation of the mechanism of the PI3K-C2β-dependent regulation of cell cycle progression and cell growth revealed that PI3K-C2β regulates cyclin B1 protein levels through modulation of microRNA miR-449a levels. Our data further demonstrate that downregulation of PI3K-C2β inhibits breast cancer cell invasion in vitro and breast cancer metastasis in vivo. Consistent with this, PI3K-C2β is highly expressed in lymph-nodes metastases compared to matching primary tumors. These data demonstrate that PI3K-C2β plays a pivotal role in breast cancer progression and in metastasis development. Our data indicate that PI3K-C2β may represent a key molecular switch that regulates a rate-limiting step in breast tumor progression and therefore it may be targeted to limit breast cancer spread.

Activity of Pan-Class I Isoform PI3K/mTOR Inhibitor PF-05212384 in Combination with Crizotinib in Ovarian Cancer Xenografts and PDX

The Phosphatidyl inositol-3 kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) and c-Met signaling pathways are often deregulated in cancer. The two pathways are interconnected and at least c-Met has been implicated in drug resistance. The aim of the study was to assess in ovarian cancer preclinical models, the efficacy and tolerability of a dual PI3K mTOR inhibitor (PF-05212384 or gedatolisib) and a c-Met inhibitor (crizotinib) either as single agents or in combination. In vitro, both PF-05212384 and crizotinib showed a concentration dependent activity in the two ovarian cancer cell lines. The combination of the two did not result in synergistic activity. A subline resistant to gedatolisib was obtained and showed an increased expression of MDR-1 gene. In vivo results show that crizotinib alone did not display any activity in all the tumors investigated, while PF-05212384 alone had some marginal activity. The combination of the two resulted in all the experiments superior to single agents with a good tolerability. Considering that crizotinib did not show activity in the models used, the results indicate that crizotinib is able to potentiate the activity of PF-05212384. Although the activity of the combination was not striking in these three models of ovarian cancer, due to the good tolerability of the combination, the results would suggest the possibility to combine the two drugs in settings in which gedatolisib or crizotinib alone have already some significant activity.

KRAS mutations affect prognosis of non-small-cell lung cancer patients treated with first-line platinum containing chemotherapy

KRAS mutations seem to indicate a poor outcome in Non-Small-Cell Lung Cancer (NSCLC) but such evidence is still debated. The aim of this planned ancillary study within the TAILOR trial was to assess the prognostic value of KRAS mutations in advanced NSCLC patients treated with platinum-based first-line chemotherapy. Patients (N = 540), enrolled in the study in 52 Italian hospitals, were centrally genotyped twice in two independent laboratories for EGFR and KRAS mutational status.

Of these, 247 patients were eligible and included in the present study. The primary endpoint was overall survival (OS) according to KRAS mutational status in patients harboring EGFR wild-type.

Sixty (24.3%) out of 247 patients harbored KRAS mutations. Median OS was 14.3 months and 10.6 months in wild-type and mutated KRAS patients, respectively (unadjusted Hazard Ratio [HR]=1.41, 95%Confidence Interval [CI]: 1.03-1.94 P = 0.032; adjusted HR=1.39, 95%CI: 1.00-1.94 P = 0.050). This study, with all consecutive patients genotyped, indicates that the presence of KRAS mutations has a mild negative impact on OS in advanced NSCLC patient treated with a first-line platinum-containing regimen. Trial Registration: clinicaltrials.gov identifier NCT00637910