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Background:EGFR/c-Met activation/amplification and co-expression, mTOR upregulation/activation, and Akt/Wnt signaling upregulation have been individually associated with more aggressive disease and characterized as potential prognostic markers for lung cancer patients.Methods:Tumors obtained from 109 participants with stage I–IV non-small cell lung cancer (NSCLC) were studied for EGFR/c-Met co-localization as well as for total and active forms of EGFR, c-Met, mTOR, S6K, beta-catenin, and Axin2. Slides were graded by two independent blinded pathologists using a validated scoring system. Protein expression profile correlations were assessed using Pearson correlation and Spearman’s rho. Prognosis was assessed using Kaplan–Meier analysis.Results:Protein expression profile analysis revealed significant correlations between EGFR/p-EGFR ( p = 0.0412) and p-mTOR/S6K ( p = 0.0044). Co-localization of p-EGFR/p-c-Met was associated with increased p-mTOR ( p = 0.0006), S6K ( p = 0.0018), and p-S6K ( p Conclusions:These findings suggest that increased EGFR/c-Met signaling is correlated with upregulated mTOR/S6K signaling, which may in turn be associated with shorter median survival in late-stage NSCLC.

Background: Autologous stem cell transplantation (ASCT) in multiple myeloma (MM) has been shown to improve survival compared to conventional chemotherapy alone. However, the ability to perform ASCT relies, in part, on collecting a sufficient number (#) of CD34+ hematopoietic stem cells (HSCs), typically from peripheral blood. The ideal HSC mobilization regimen would enable collection of optimal #s of HSCs (5-6x10 6 CD34+ cells/kg) within the minimum # of apheresis sessions possible. Yet, despite currently available G-CSF (G) based mobilization regimens and multiple apheresis days, many remain unable to collect optimal #s of HSCs. Motixafortide (M) is a novel CXCR4 inhibitor, with high affinity (IC 50 0.54-4.5 nM) and long receptor occupancy (>48 hours). Methods: In this prospective, phase 3, double blind, placebo controlled, multicenter trial, 122 patients were randomized (2:1) to receive either M+G or placebo (P)+G for HSC mobilization prior to ASCT for MM. All patients received G (10 mcg/kg) on days 1-5 (and 6-8, if needed). Patients received either M (1.25 mg/kg, subcutaneous injection) or P on day 4 (and 6, if needed). Apheresis began day 5, with the primary (PEP) and secondary (SEP) endpoints of collecting ≥6x10 6 CD34+ cells/kg in up to 2 apheresis days or 1 day, respectively. Apheresis continued on days 6-8 if needed. Total CD34+ cells/kg were analyzed on site to determine if patients mobilized to the goal and all samples were subsequently sent for assessment by central laboratory. Patients that did not collect ≥2x10 6 CD34+ cells/kg by day 8 proceeded to rescue mobilization. The # of CD34+ cells infused was determined independently by each investigator according to local practice (minimum ≥2x10 6 CD34+ cells/kg). Analyses of the PEP/SEPs were performed on an intent-to-treat basis. Results: Demographics between the 2 treatment arms were similar. Mobilization with M+G resulted in 92.5% of patients collecting ≥6x10 6 CD34+ cells/kg within 2 apheresis days vs 26.2% with P+G (Odds Ratio (OR) 53.3, 95% CI 14.12-201.33, p Conclusions: A single injection of M on top of G significantly increased the proportion of patients mobilizing ≥6x10 6 CD34+ cells/kg for ASCT (92.5%) vs G (26.2%) in up to 2 apheresis days (p Figure 1 Figure 1. Disclosures Crees: BioLineRx Ltd.: Research Funding. Larson: TORL biotherapeutics: Current holder of individual stocks in a privately-held company; Bioline: Research Funding; Abbvie: Research Funding; BMS: Research Funding; Celgene: Research Funding; GSK: Research Funding; Janssen: Research Funding; Juno: Research Funding; Novartis: Research Funding; Pfizer: Research Funding; Takeda: Research Funding. Illés: Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees. Stiff: Incyte: Research Funding; Cellectar: Research Funding; Seagen: Research Funding; Gamida Cell: Research Funding; Cellectar: Research Funding; Actinium: Research Funding; Bristol Myers Squibb: Research Funding; BioLineRX: Research Funding; Macrogenics: Research Funding; CRISPR Therapeutics: Consultancy, Honoraria; Amgen: Research Funding; Janssen: Research Funding; Kite, a Gilead Company: Research Funding; Karyopharm: Consultancy, Honoraria; MorphoSys: Consultancy, Honoraria. Sborov: Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Consultancy; Sanofi: Consultancy; SkylineDx: Consultancy. Pereira: Jazz Pharmaceutical: Membership on an entity's Board of Directors or advisory committees. Mikala: Novartis: Consultancy; Takeda: Consultancy; Abbvie: Consultancy; Krka: Consultancy; Janssen: Consultancy; Amgen: Consultancy; Celgene: Consultancy. Holtick: Celgene: Honoraria; Sanofi: Honoraria. Qazilbash: Amgen: Research Funding; Oncopeptides: Other: Advisory Board; Bristol-Myers Squibb: Other: Advisory Board; Biolline: Research Funding; Angiocrine: Research Funding; NexImmune: Research Funding; Janssen: Research Funding. Hardy: American Gene Technologies, International: Membership on an entity's Board of Directors or advisory committees; Kite/Gilead: Membership on an entity's Board of Directors or advisory committees; InCyte: Membership on an entity's Board of Directors or advisory committees. Vainstein: BioLineRx LTD: Current Employment. Sorani: BioLineRx LTD: Current Employment. Gliko-Kabir: BioLineRx Ltd.: Current Employment. Goldstein: BioLineRx Ltd.: Current Employment. Kadosh: BioLineRx Ltd.: Current Employment.

Background: CD34+ hematopoietic stem and progenitor cell (HSPC) dose during hematopoietic cell transplantation (HCT) remains one of the most reliable clinical parameters to predict quality of engraftment. A minimum HSPC dose of 2-2.5x10 6 CD34+ cells/kg is considered necessary for reliable engraftment, while optimal doses of 5-6x10 6 CD34+ cells/kg are associated with faster engraftment, as well as fewer transfusions, infections, and antibiotic days. CXCR4 inhibition significantly improves the number (#) of CD34+ HSPCs mobilized for HCT, when added to G-CSF (G). Motixafortide (M), a novel CXCR4 antagonist, is a potent mobilizer of HSPCs recently evaluated in the phase 3, double blind, placebo controlled, multicenter GENESIS Trial as a mobilizing agent prior to autologous HCT (ASCT) in multiple myeloma (MM). Methods: Patients received G (10 mcg/kg) on days 1-5 (and days 6-8, if needed). On day 4 (and day 6, if needed), patients received either M (1.25 mg/kg) or placebo (P). Apheresis began day 5, with up to 4 days of apheresis if needed. The primary and secondary endpoints were collection of ³6x10 6 CD34+ cells/kg in up to 2 days of apheresis or 1 day, respectively. The # of CD34+ cells/kg infused was determined independently by each investigator according to local practice, but a minimum of ³2x10 6 CD34+ cells/kg was required. A post-hoc analysis was performed pooling data from both arms to evaluate time to platelet engraftment (TPE) (≥20x10 9/L without transfusions x7 days) and neutrophil engraftment (TNE) (ANC ≥0.5x10 9/L x3 days) based on total # of CD34+ cells/kg and # of specific CD34+ HSPC subsets infused. CD34+ HSPC immunophenotyping was performed via multicolor fluorescence-activated cell sorting (FACS). TPE/TNE was analyzed using Kaplan-Meier curves and Cox proportional hazards model. Results: 114 MM patients underwent apheresis, ASCT and were evaluable (M+G N=77; P+G N=37). M+G mobilization yielded a median of 10.8x10 6 CD34+ cells/kg collected in 1 apheresis vs 2.3x10 6 CD34+ cells/kg with P+G (p75 th percentile) of combined CD34+ HSC, MPP, CMP and GMP subsets was associated with faster TPE of 12 days vs 19 days with lower #s of these subsets (p=0.003) (Figure 2A). Furthermore, higher #s (>75 th percentile) of GMPs was individually associated with faster TPE of 13 days vs 19 days with lower GMP cell doses (p=0.0116) (Figure 2C). TNE was not impacted by increasing doses of total CD34+ HSPCs or any specific CD34+ HSPC subset (all p>0.05) (Figures 1B, 2B and 2D). Conclusions: M+G mobilization enabled significantly more CD34+ cells to be collected in 1 apheresis (median 10.8x10 6 CD34+ cells/kg) vs P+G (2.3x10 6 CD34+ cells/kg), as well as 3.5-5.6 fold higher #s of HSCs, MPPs, CMPs and GMPs (all p-values Figure 1 Figure 1. Disclosures Crees: BioLineRx Ltd.: Research Funding. Retting: BioLineRx Ltd.: Research Funding. Larson: TORL biotherapeutics: Current holder of individual stocks in a privately-held company; Abbvie, Bioline, BMS, Celgene, GSK, Janssen, Juno, Novartis, Pfizer, Takeda: Research Funding. Illes: Novartis, Janssen, Pfizer, Roche: Other: Travel, Accommodations, Expenses; Takeda, Seattle Genetics: Research Funding; Janssen, Celgene, Novartis, Pfizer, Takeda, Roche: Consultancy. Stiff: CRISPR: Consultancy; Gamida-Cell, Atara, Amgen, Incyte, Takeda, Macrogenetics, Eisai: Research Funding. Sborov: SkylineDx: Consultancy; GlaxoSmithKline: Consultancy; Sanofi: Consultancy; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees. Pereira: Jazz Pharmaceutical: Membership on an entity's Board of Directors or advisory committees. Mikala: Abbvie: Consultancy; Amgen: Consultancy; Celgene: Consultancy; Janssen: Consultancy; Krka: Consultancy; Novartis: Consultancy; Takeda: Consultancy. Holtick: Sanofi: Honoraria; Celgene: Honoraria. Qazilbash: Janssen: Research Funding; Oncopeptides: Other: Advisory Board; Biolline: Research Funding; Bristol-Myers Squibb: Other: Advisory Board; NexImmune: Research Funding; Amgen: Research Funding; Angiocrine: Research Funding. Hardy: Kite/Gilead: Membership on an entity's Board of Directors or advisory committees; American Gene Technologies, International: Membership on an entity's Board of Directors or advisory committees; InCyte: Membership on an entity's Board of Directors or advisory committees. Sorani: BioLineRx LTD: Current Employment. Shemesh-Darvish: BioLineRx LTD: Current Employment. Vainstein: BioLineRx LTD: Current Employment; Enlivex: Consultancy. Kadosh: StatExcellence: Current holder of individual stocks in a privately-held company; BioLineRx: Honoraria.

Background: CD34 expression remains the most common immunophenotypic cell surface marker defining human hematopoietic stem and progenitor cells (HSPCs). Recently, use of multicolor fluorescence-activated cell sorting (mFACS) and single-cell RNA sequencing (scRNA seq) has illustrated the heterogenous nature of CD34+ HSPCs, with immunophenotypically and transcriptionally distinct subsets ranging from primitive hematopoietic stem cells (HSCs) capable of long-term multilineage potential to differentiated, lineage-committed progenitors. Meanwhile, the addition of CXCR4 inhibitors (CXCR4i) to G-CSF (G) has increased mobilization of CD34+ HSPCs for stem cell transplantation (SCT). Yet, the effect of CXCR4i +/- G on mobilization of specific immunophenotypic and transcriptional CD34+ HSPC subsets is not well-characterized. Motixafortide (M) is a novel cyclic peptide CXCR4i with a low receptor off rate and extended in vivo action vs plerixafor (Px). M was recently evaluated in the phase 3, double blind, placebo controlled GENESIS Trial as an HSPC mobilizer prior to autologous SCT (ASCT) in multiple myeloma (MM). Methods: GENESIS Trial patients were prospectively randomized (2:1) to receive either M+G or placebo (P)+G for HSPC mobilization. Demographically similar patients undergoing mobilization with Px+G prior to ASCT for MM were prospectively enrolled on a parallel tissue banking protocol. All patients received G (10 mcg/kg) on days 1-5 (and 6-8 if needed). Patients also received either M (1.25 mg/kg) or P on day 4 (and 6 if needed); or Px (0.24 mg/kg) on day 4 (and 5-7 if needed). Apheresis began day 5 (and 6-8 if needed). HSPCs were purified from apheresis product on day 5 via CD34+ immunomagnetic selection. CD34+ HSPC subset profiling was performed via mFACS and scRNA seq. CXCR4 expression and receptor occupancy was evaluated by antibody binding capacity of 12G5 and 1D9 clones. Results: Demographics were similar between the M+G (n=24), P+G (n=13) and Px+G (n=14) cohorts. By mFACS, M+G mobilized a 5.5 fold higher absolute number (#) of HSCs, multipotent progenitors (MPP) and common myeloid progenitors (CMP) vs P+G (p0.05). 1D9 binding to CXCR4 on CD34+ HSPCs was similar between all 3 arms (p-values 0.45-0.75). 12G5 binding (which competes with CXCR4i's for binding to CXCR4) was significantly lower with M+G (MFI:11) vs P+G (MFI:74; p By scRNA seq, UMAP clustering identified 3 transcriptionally similar HSC sub-clusters (HSC-I, -II and -III) mobilized by all 3 regimens; and 1 distinct HSC-PL cluster mobilized by P+G expressing heat shock protein genes (HSPA1 A/B) (Figure 1C). Differentially expressed genes (DEGs) of HSCs I-III included CD52, FTH1, HLA-E, KLF2 and LMNA. AVP was unique to HSC-I while EGR1, JUN and ZFP36 were unique to HSC-III. MPPs clustered into 3 sub-clusters (MPP-I, -II and -III). MPP-I clustered closely to HSC-II/III with low expression of genes of differentiation. MPP-II expressed DEGs (PLEK) on a continuum toward megakaryocyte-erythroid progenitors (MEP-I/II), which expressed DEGs of erythroid differentiation (HBD/HBB). MPP-I and -II contained cells from all 3 regimens. However, MPP-III was specific to M+G with DEGs (MT-ATP8, HIST1H1) associated with monocyte, lymphocyte and NK cell differentiation. Conclusions: Extended CXCR4i with M+G mobilized significantly higher #s of combined CD34+ HSCs, MPPs and CMPs vs Px+G and P+G (p-values Figure 1 Figure 1. Disclosures Crees: BioLineRx Ltd.: Research Funding. Retting: BioLineRx Ltd.: Research Funding. Jayasinghe: WUGEN: Consultancy; MMRF: Consultancy. Vainstein: BioLineRx LTD: Current Employment. Sorani: BioLineRx LTD: Current Employment. Ickowicz: BioLineRx Ltd.: Current Employment. Shemesh-Darvish: BioLineRx LTD: Current Employment. Kadosh: BioLineRx Ltd.: Current Employment.

Simple Summary B-cell lymphomas are the most commonly occurring blood cancer and the second leading cause of cancer-related death among blood cancers. Chemotherapy and stem cell transplantation have long served as the standard therapies for relapsed or refractory aggressive B-cell lymphomas with very poor survival, historically. Recently, the development of multiple chimeric antigen receptor T-cell (CAR-T) products has translated into dramatically improved outcomes and survival for patients with relapsed or refractory B-cell lymphoma. Meanwhile, basic, translational and clinical development within the field has progressed rapidly. The aim of this review is to summarize the current state of the art of CAR-T therapies for B-cell lymphomas within this rapidly evolving field, focusing on current United States Food and Drug Administration (US FDA)-approved products and a selection of promising areas of future clinical development. Abstract Non-Hodgkin Lymphoma accounts for >460,000 cases and >240,000 deaths globally and >77,000 cases and >20,000 deaths in the U.S. annually, with ~85% of cases being B-cell malignancies. Until recently, patients with relapsed/refractory B-cell lymphoma following standard chemotherapy in combination with anti-CD20 monoclonal antibodies and autologous stem cell transplantation experienced a median overall survival (OS) of 3 years median OS. Here, we review the current state of the art of CD19 CAR-T therapies for B-cell lymphomas, focusing on current updates in US FDA-approved products, along with their associated efficacy and toxicities. Lastly, we highlight a selection of promising clinical developments in the field, including various novel strategies to increase CAR-T therapy efficacy while mitigating toxicity.

e20024 Background: Chimeric antigen receptor (CAR) T-cell therapies are in clinical development for multiple myeloma (MM). Patient-reported outcomes (PRO) can provide valuable insights into how patients perceive the relative risks and benefits of these new therapies. This study aimed to evaluate CAR T-cell therapy in relapsed/refractory MM (RRMM) patients. Methods: We utilized HealthTree Cure Hub for Multiple Myeloma to analyze patient-reported data from 17 patients who participated in CAR T-cell clinical trials. In this study, we examined total prior lines of therapy, time to next treatment (TNT), overall survival (OS), patient-reported toxicity and severity, and patient-reported outcomes (myeloma reduction or no myeloma reduction). The Kaplan-Meier model was used to calculate overall survival. The severity of toxicity was assessed using a 1 to 10 scale (1 = minimal and 10 = severe). Results: Our analysis of the 17 patients found a median of 10 lines of therapy prior to CAR T-cell treatment. Ten patients had no new treatments to report at the time of this study, 5 patients reported new treatment with a median TNT of 15.9 months, and for 2 patients we did not have data. The median OS was 24 months (95% CI 21-30 months). The probability that a patient remained alive at 2 years was 0.48 (95% CI: 0.195, 1). Four of the 17 patients died with a median of 22.5 months post-CAR T-cell therapy. Two of these patients died without reporting a change in treatment. There was a total of 36 different side effects reported by patients as a result of the therapy. Table lists the side effects experienced by 2 or more patients and the corresponding average severity. Finally, 76% of patients treated with CAR T-cell therapy reported a reduction in their myeloma, four of these patients had m-protein levels reported and saw an average decrease of 93%. Of the remaining patients, three (18%) reported little to no reduction in their myeloma, and one patient (6%) did not know their response at the time of this analysis. Conclusions: Our investigation of patient-reported results suggests an emerging and viable immunotherapy treatment option for RRMM, with encouraging outcomes and manageable side effects. Future directions include analysis of genetics and treatment options post CAR T-cell therapy. These data highlight the expedited benefit of using PROs via an online platform, like HealthTree Cure Hub, to assess new therapeutics in the research community.[Table: see text]

e20022 Background: Patient-reported data play a critical role in assessing clinical benefit from therapeutic interventions and are increasingly used in clinical trials. Internet-based platforms such as HealthTree Cure Hub for Multiple Myeloma ( www.healthtree.org ) provide the opportunity to obtain such real-world patient-reported data, while also providing valuable insights into high-yield areas to focus on quality-improvement efforts. For example, proteasome inhibitor (PI)-based maintenance after autologous stem cell transplantation (ASCT) is a consensus recommendation in many practice guidelines for high-risk multiple myeloma (MM) yet real-world adherence to this practice remains uncertain (PMID 23541011, 30932732). Methods: We examined post-ASCT maintenance therapy in patients with high-risk MM, as defined per mSMART criteria, using patient-reported treatment data from the HealthTree Cure Hub for Multiple Myeloma database. Patients who received an ASCT prior to 2014 were excluded. Results: Our analysis identified 110 MM patients with high-risk MM. Of those, only 48 (44%) received PI-based maintenance therapy. Additionally, 60 (55%) received IMiD (immunomodulatory imide drug) maintenance, 1 (< 1%) received ‘other’, and 1 (< 1%) did not report maintenance therapy. Conclusions: The benefits of PI-based maintenance in MM are well established for high-risk MM. However, analysis of patient-reported data using an online patient portal, HealthTree Cure Hub for Multiple Myeloma, suggests a disparity between practice recommendations and real-world practice patterns. These findings, and others from online patient portals, can serve as a springboard in helping investigators to identify areas for quality-improvement initiatives.

Background: Gemcitabine, alone or in combination with other agents, has become an important part of the standard of care for treatment of both resectable and unresectable/advanced pancreatic adenocarcinoma. Gemcitabine is generally considered to have a favorable toxicity profile, with myelosuppression and hepatotoxicity as the most common adverse effects. There are just two prior published case reports of gemcitabine-associated digital toxicity in the treatment of pancreatic adenocarcinoma, and few case reports when considering all solid tumors. Presentation: A 70-year-old female developed hand numbness and tingling while receiving nab-paclitaxel plus gemcitabine for metastatic pancreatic adenocarcinoma. There was initial concern for Raynaud's or nab-paclitaxel-associated neuropathy, thus nab-paclitaxel was discontinued. However, her symptoms progressed to severe pain and her digits became dusky. An extensive evaluation revealed no alternative etiology except gemcitabine-associated digital ischemia (DI). The patient was treated with discontinuation of gemcitabine, and starting nitrates, opiates, calcium-channel blockers, and enoxaparin but eventually progressed to dry gangrene. Conclusion: Here we report a case of gemcitabine-associated DI, along with a review of the literature. Although a rare complication, DI must be recognized and treated promptly to reduce the likelihood of serious and permanent morbidity.

Effective hematopoietic cell transplantation relies upon collecting adequate numbers of CD34+ hematopoietic stem cells, typically from peripheral blood. A minimum of ≥2 × 106 CD34+ cells/kg are necessary, while transplants of ≥5–6 × 106 CD34+ cells/kg are associated with improved hematopoietic recovery. Granulocyte colony stimulating factor (G-CSF) remains the gold standard for hematopoietic stem cell mobilization. However, in randomized trials for autologous-hematopoietic cell transplantation in multiple myeloma, approximately 45% of patients remain unable to optimally mobilize with G-CSF alone despite multiple injections and apheresis days. Therefore, reducing mobilization failures remains an unmet need. The study objective is to evaluate the superiority of one dose of BL-8040 plus G-CSF over placebo plus G-CSF to mobilize ≥6.0 × 106 CD34+ cells/kg in up to two apheresis days. ClinicalTrials.gov: NCT03246529

Cancer is a leading cause of death worldwide and an estimated 1 in 4 deaths in the United States is due to cancer. Despite recent advances in cancer treatment, adverse effects related to cancer therapy remain a limiting factor for many patients. The ideal cancer treatment would selectively target cancerous cells while sparing normal, healthy cells to offer maximal therapeutic benefit while minimizing toxicity. Telomeres are structurally unique DNA sequences at the end of human chromosomes, which play an integral role in the cellular mortality of normal cells. As telomeres shorten with successive cellular divisions, cells develop chromosomal instability and undergo either apoptosis or senescence. In many cancers, this apoptosis or senescence is avoided as normal telomere length is maintained by a ribonucleoprotein reverse transcriptase called telomerase. Telomerase is expressed in more than 85% of all cancers and confers cancerous cells with a replicative immortality, which is a hallmark of malignant tumors. In contrast, telomerase activity is not detectable in the majority of normal somatic cell populations. Therefore, the targeting of telomerase and telomere maintenance mechanisms represent a potentially promising therapeutic approach for various types of cancer. This review evaluates the roles of GRN163L, T-oligo and small molecule G-quadruplex stabilizers as potential anticancer therapies by targeting telomerase and other telomere maintenance mechanisms.

Numerous tyrosine kinase inhibitors (TKIs) targeting c-Met are currently in clinical trials for several cancers. Their efficacy is limited due to the development of resistance. The present study aims to elucidate this mechanism of c-Met TKI resistance by investigating key mTOR and Wnt signaling proteins in melanoma cell lines resistant to SU11274, a c-Met TKI. Xenografts from RU melanoma cells treated with c-Met TKIs SU11274 and JNJ38877605 showed a 7- and 6-fold reduction in tumor size, respectively. Resistant cells displayed upregulation of phosphorylated c-Met, mTOR, p70S6Kinase, 4E-BP1, ERK, LRP6, and active β-catenin. In addition, GATA-6, a Wnt signaling regulator, was upregulated, and Axin, a negative regulator of the Wnt pathway, was downregulated in resistant cells. Modulation of these mTOR and Wnt pathway proteins was also prevented by combination treatment with SU11274, everolimus, an mTOR inhibitor, and XAV939, a Wnt inhibitor. Treatment with everolimus, resulted in 56% growth inhibition, and a triple combination of SU11274, everolimus and XAV939, resulted in 95% growth inhibition in RU cells. The V600E BRAF mutation was found to be positive only in MU cells. Combination treatment with a c-Met TKI and a BRAF inhibitor displayed a synergistic effect in reducing MU cell viability. These studies indicate activation of mTOR and Wnt signaling pathways in c-Met TKI resistant melanoma cells and suggest that concurrent targeting of c-Met, mTOR, and Wnt pathways and BRAF may improve efficacy over traditional TKI monotherapy in melanoma patients.

Richard E Mulnix,1,* Ryan T Pitman,1 Allison Retzer,2 Ceyda Bertram,1 Kavin Arasi,2 Zachary Crees,2 Jennifer Girard,2 Srijayaprakash B Uppada,1 Amanda L Stone,1 Neelu Puri1,* 1Department of Biomedical Sciences, University of Illinois at Chicago, Rockford, IL, USA; 2College of Medicine, University of Illinois at Chicago, Rockford, IL, USA *These authors contributed equally to this work Background: Experimental disruption of the telomere overhang induces a potent DNA damage response and is the target of newly emerging cancer therapeutics. Introduction of T-oligo, an eleven-base oligonucleotide homologous to the 3'-telomeric overhang, mimics telomere disruption and induces DNA damage responses through activation of p53, p73, p95/Nbs1, E2F1, pRb, and other DNA damage response proteins. ATM (ataxia telangiectasia mutated) was once thought to be the primary driver of T-oligo-induced DNA damage responses; however, recent experiments have highlighted other key proteins that may also play a significant role. Methods: To identify proteins associated with T-oligo, MM-AN cells were treated with biotinylated T-oligo or complementary oligonucleotide, cell lysates were run on SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis), and the protein bands observed after treatment of cells with T-oligo or complementary oligonucleotide were analyzed using mass spectrometry. To study the effect of T-oligo on expression of hnRNP C1/C2 (heterogeneous nuclear ribonucleoprotein C1 and C2) and purine-rich element binding proteins (Pur proteins), cells were treated with T-oligo, and immunoblotting experiments were performed. To determine their role in senescence, cells were treated with shRNA (short hairpin ribonucleic acid) against these proteins, and senescence was studied using the senescence associated beta-galactosidase assay. Results: Using mass spectrometry, RNA-binding hnRNP C1/C2 and DNA-binding Pur proteins were found to associate with T-oligo. hnRNP C1/C2 exhibited increased expression (3.6–12.0-fold) in non-small-cell lung cancer (NSCLC) and in melanoma cells (4.5–5.2-fold), and Pur proteins exhibited increased expression of 2.2-fold in NSCLC and 2.0-fold in melanoma cells after T-oligo treatment. Experimental knockdown of hnRNP C1/C2 and Pur-beta completely abrogated T-oligo induced senescence in both MU melanoma and H358 NSCLC cells. Additionally, knockdown of Pur-beta prevented T-oligo-induced phosphorylation of p53, hypophosphorylation of pRb, and upregulation of E2F1, p21, and p53. Conclusion: These novel findings highlight proteins essential to T-oligo's anticancer effects that may be of interest in telomere biology and cancer therapeutics. Keywords: T-oligo, melanoma, NSCLC, p53, p21, pRb

β-Cells of the islet of Langerhans produce insulin to maintain glucose homeostasis. Self-replication of β-cells is the predominant mode of postnatal β-cell production in mammals, with about 20% of rodent β cells dividing in a 24-hour period. However, replicating β-cells are rare in adults. Induction of self-replication of existing β-cells is a potential treatment for diabetes. In zebrafish larvae, β-cells rarely self-replicate, even under conditions that favor β-cell genesis such overnutrition and β-cell ablation. It is not clear why larval β-cells are refractory to replication. In this study, we tested the hypothesis that insufficient activity of cyclin-dependent kinase 4 may be responsible for the low replication rate by ectopically expressing in β-cells a mutant CDK4 (CDK4(R24C)) that is insensitive to inhibition by cyclin-dependent kinase inhibitors. Our data show that expression of CDK4(R24C) in β-cells enhanced β-cell replication. CDK4(R24C) also dampened compensatory β-cell neogenesis in larvae and improved glucose tolerance in adult zebrafish. Our data indicate that CDK4 inhibition contributes to the limited β-cell replication in larval zebrafish. To our knowledge, this is the first example of genetically induced β-cell replication in zebrafish.

NSCLC tumors acquire resistance to EGFR-TKIs, and studies have suggested that co-localization of c-MET and EGFR may be a modality of acquired resistance. Upregulation of alternative signaling pathways such as Wnt or mTOR have been shown to be associated with poor prognosis and are a potential mechanism of resistance. This study aims at examining these signaling pathways and EGFR/c-MET co-expression in 100 patients with stage I-IV NSCLC. We have data on 50 patients, and are working on the remaining samples. Tumor tissue from biopsies or resections have been obtained with IRB approval, processed, sectioned, and mounted on microscope slides. Total and active forms of EGFR, c-MET, mTOR, S6K, beta-catenin, and Axin2 were detected using singleplex or multiplex IHC staining procedures, and stains were graded by an independent pathologist using a validated scoring system. We selected Stage IV NSCLC (n = 32) patients to correlate EGFR/c-MET expression with overall survival, and analyzed them for months to mortality based on high or low EGFR expression. Patients with high EGFR expression (n = 16) showed lower overall survival compared to those with low EGFR expression (n = 16). Expression of c-MET is linked to decreased survival in Stage IV NSCLC patients (n = 4). Patients with EGFR/c-MET co-localization (n = 19) showed decreased overall survival compared to patients without EGFR/c-MET co-localization (n = 9). Elevated mTOR and p-mTOR are associated with worse prognosis in Stage IV NSCLC patients. Patients categorized with either low mTOR expression (n = 10) or high mTOR expression (n = 19) showed increased mortality with high mTOR expression (5.9 months) compared to patients with low mTOR expression (13.5 months). A similar trend was seen in patients with either low (n = 4, 7.5 months) or high (n = 24, 15.9 months) p-mTOR expression. Patients with low beta-catenin expression (n = 4) showed improved survival in comparison to patients with high beta-catenin expression (n = 18), 9.4 months vs 6.3 months, respectively. To determine correlations in expression of these proteins we found that EGFR/c-MET co-expression is inversely correlated with active beta-catenin and directly correlated with a negative regulator of beta-catenin, Axin-2 suggesting EGFR/c-MET co-expression is associated with a downregulation of Wnt activity. In contrast, elevated EGFR/c-MET co-expression and co-activation is statistically significantly correlated with elevated mTOR-S6K expression and activation suggesting EGFR/c-MET co-expression is associated with an upregulation of the mTOR pathway activity. Elevated mTOR pathway activation at the time of diagnosis is statistically significantly associated with poor prognosis in patients with stage IV NSCLC. These preliminary results suggest that mTOR inhibition therapy in addition to EGFR/c-MET inhibition therapies may be beneficial in this population. Citation Format: Zachary Crees, Caleb Shearrow, Leo Lin, Jennifer Girard, Kavin Arasi, Aayush Bhoraskar, Andrew Nowak, Bonnie Sheu, Gagan Chhabra, Shylendra Sreenivassappa, Connie Vitali, Odile David, Neelu Puri. Correlation of expression of EGFR, cMET and mTOR signaling pathway proteins with each other and their impact on prognosis in non-small cell lung cancer patients. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4755.

The vitamin D receptor (VDR) has been studied as a novel target for cancer therapy in many tissue types as VDR ligands decrease cell proliferation in vitro and decrease tumor growth in vivo in sensitive cells. The objective of this study was to analyze the response to VDR agonist therapy in a panel of validated thyroid cancer cells and assess genetic markers predicting sensitivity and resistance to calcitriol and the noncalcemic analog DP006.Thyroid cancer cell lines were analyzed for VDR and RXR protein by Western blot. Cell growth after VDR agonist treatment (calcitriol or DP006) was assessed after 6 days of treatment by viable cell assay. To investigate calcitriol/DP006 resistance in VDR-expressing cells, the VDR was sequenced and 1-α and 24-hydroxylase mRNA expression was assessed.VDR protein was variably expressed in the thyroid cancer cell lines and its presence was not sufficient for decreased viable cell count in response to calcitriol or DP006. The most sensitive cells (TPC1) have an ff FokI VDR polymorphism and the most resistant cells (HTh7 and 8505C) have an FF FokI VDR. This is a unique finding given that the balance of the literature of VDR polymorphisms describes an association of the ff FokI polymorphism with cancer risk and/or decreased VDR transactivation. 1-α and 24-hydroxylase mRNA expression before and after VDR agonist therapy was examined. 1-α-Hydroxylase levels did not change after calcitriol treatment. However, we found that higher baseline 24-hydroxylase levels and/or lower stimulation of 24-hydroxylase levels after calcitriol treatment were associated with relative resistance to calcitriol/DP006.The VDR represents a novel therapeutic target in poorly differentiated thyroid cancer; however, the efficacy of VDR agonist therapy to decrease viable thyroid cancer cell count cannot be predicted solely on the presence of the VDR. The FF FokI VDR genotype and high baseline 24-hydroxylase levels were associated with relative resistance to calcitriol and DP006. Therefore, identifiable markers of sensitivity or resistance to VDR agonist therapy may allow for a personalized use of these agents in poorly differentiated thyroid cancer.

Lung cancer is projected to be the number one cause of cancer mortality in the United States in 2014. Therapies such as tyrosine kinase inhibitors (TKIs) have been developed to treat non-small cell lung cancer (NSCLC), which accounts for 80-85% of all lung cancer cases. EGFR is a protein that is often targeted by these TKIs and several EGFR-TKIs have been approved for clinical use. However, NSCLC tumors almost inevitably acquire resistance to EGFR-TKIs, limiting drug efficacy. Previous studies have suggested that co-localization of c-MET and EGFR may be one possible modality of acquired resistance. Additionally, upregulation of alternative signaling pathways such as Wnt or mTOR have been shown to be associated with poor prognosis and have been described as potential mechanisms of resistance. Thus, this study examined these signaling pathways and the status of EGFR/c-Met co-expression in 42 patients with stage I-IV NSCLC. Tumor tissue from biopsy or resection was obtained with patient consent and IRB approval and was subsequently processed, sectioned, and mounted on microscope slides. Total and active forms of EGFR, c-Met, mTOR, S6K, β-Catenin, and Axin2 were detected using a singleplex or multiplexed immunohistochemistry staining procedure, and stains were graded by an independent pathologist using a validated scoring system. 65.9% of patients exhibited co-expression of EGFR and c-Met (n = 27) while 51.2% showed co-activation of the two markers (n = 21). Additionally, we observed EGFR/c-Met co-expression to have a statistically significant positive correlation with mTOR expression with a Spearman's rho of 0.411 (p = 0.033), suggesting EGFR/c-Met co-expression may play a role in tumorigenesis possibly via regulation of the mTOR pathway. This notion is further supported by our finding that expression of pS6K, a downstream mTOR pathway protein, showed a strong positive correlation with EGFR expression with a Spearman's rho of 0.504 (p = 0.001). In contrast, Wnt pathway protein active β-Catenin exhibits a negative correlation with EGFR expression while Axin2, a negative regulator of active β-Catenin, showed a positive correlation. Our findings indicate an inverse relationship between the two signaling pathways in NSCLC with increasing mTOR activation correlating with Wnt downregulation. Furthermore, EGFR expression may be associated with this relationship. Thus, we conclude that EGFR/c-Met co-expression as well as activation of the mTOR pathway may be involved in enhanced pathogenesis of NSCLC and possibly acquired resistance to EGFR-TKI therapy. Citation Format: Caleb Shearrow, Zachary Crees, Jennifer Girard, Kymberly Harrington, Kavin Arasi, Ceyda Bertram, Andrew Nowak, Leo Lin, Bonnie Sheu, Sunil Palani, Neelu Puri. Expression profiles of EGFR, c-Met, and mTOR/Wnt alternative signaling pathway proteins in non-small cell lung cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 743. doi:10.1158/1538-7445.AM2015-743

Current EGFR/c-Met tyrosine kinase inhibitor (TKI) combination therapies are shown to be susceptible to acquired resistance in the majority of NSCLC patients. To understand how cells develop EGFR/c-Met TKI resistance, we use three model NSCLC cell lines: H2170, H358 and H1975. H2170 and H358 cell lines express high levels of EGFR and c-Met and are EGFR wild-type. These cell lines were made resistant to the EGFR TKI erlotinib, the c-Met TKI SU11274 and a combination of both by exposure to increasing concentrations of these TKIs. The H1975 cell line is positive for two EGFR TKD mutations (T790M and L858R) which confer resistance to erlotinib. Studies have shown that EGFR/c-Met TKI resistant cells may use alternative signaling pathways to activate downstream transcription/translation proteins previously activated by EGFR and c-Met signaling. The Wnt/β-catenin and mTOR pathways are demonstrated to have significant roles in cell survival, resistance and tumorigenesis in NSCLC. Several EGFR/c-Met-linked proteins in these two signaling pathways were differentially modulated in H2170 and H358 resistant lines. The Wnt signaling transducer β-catenin plays a role in cellular proliferation and death and its deregulation is implicated in lung cancer. Protein kinase GSK-3 also plays an important role in lung cancer and its inhibition by Wnt results in mTOR activation. It is encoded by two genes, GSK-3α and GSK-3β. GATA-6 is a transcriptional activator of Wnt and is also implicated in several cancers. Active β-catenin was found to be 2 to 4-fold upreglated in H2170 SU11274-resistant (SR) cells and 2 to 20-fold upreglated in H2170 erlotinib-resistant (ER) cells, in the presence and absence of TKIs and growth factor ligands, when compared to naïve H2170 cells. GATA-6 was found to be 1.5 to 4-fold upreglated in H2170 SR cells and 2 to 3-fold upreglated in H2170 ER cells. Conversely, p-GSK-3α and p-GSK-3β were found to be 1.2 to 4.8-fold and 1.5 to 10.7-fold downreglated in H2170 SR cells, respectively. These results indicate increased activation of the Wnt/β-catenin and mTOR pathways in TKI resistant cells. We are currently studying the expression of these proteins further in the H1975 cell line. To translate our studies to patients, we are investigating the role of EGFR/c-Met synergism in NSCLC by conducting a retrospective biomarker analysis using IHC on 100 tissue samples from patients with stage 3 and 4 squamous cell and adenocarcinoma. Preliminary results indicate that EGFR and c-Met receptors are co-expressed in lung cancer tissues and we are acquiring data to determine how co-localization and synergism affects patient prognosis. Further studies are being conducted on proteins in the Wnt and mTOR signaling pathways, such as p70S6Kinase, mTOR, β-Catenin and Axin-2, and their involvement in patient prognosis and resistance. This study may provide clinicians with novel targets for improving treatment options for future NSCLC patients. Citation Format: Gregory Michael Botting, Kymberly Harrington, Caleb Shearrow, Zachary Crees, Jennifer Girard, Kavin Arasi, Neelu Puri. Mechanism of EGFR and c-Met TKI resistance and role of co-expression of EGFR and c-Met in non-small cell lung cancer patients. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1838. doi:10.1158/1538-7445.AM2014-1838