Particulate matter-induced metabolic recoding of epigenetics in macrophages drives pathogenesis of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a group of illnesses associated with unresolved inflammation in response to toxic environmental stimuli. Persistent exposure to PM is a major risk factor for COPD, but the underlying mechanism remains unclear. Using our established mouse model of PM-induced COPD, we find that repeated PM exposure provokes macrophage-centered chronic inflammation and COPD development. Mechanistically, chronic PM exposure induces transcriptional downregulation of HAAO, KMO, KYNU, and QPRT in macrophages, which are the enzymes of de novo NAD+ synthesis pathway (kynurenine pathway; KP), via elevated chromatin binding of the CCCTC-binding factor (CTCF) near the transcriptional regulatory regions of the enzymes. Subsequent reduction of NAD+ and SIRT1 function increases histone acetylation, resulting in elevated expression of pro-inflammatory genes in PM-exposed macrophages. Activation of SIRT1 by nutraceutical resveratrol mitigated PM-induced chronic inflammation and COPD development. In agreement, increased levels of histone acetylation and decreased expression of KP enzymes were observed in pulmonary macrophages of COPD patients. We newly provide an evidence that dysregulated NAD+ metabolism and consecutive SIRT1 deficiency significantly contribute to the pathological activation of macrophages during PM-mediated COPD pathogenesis. Additionally, targeting PM-induced intertwined metabolic and epigenetic reprogramming in macrophages is an effective strategy for COPD treatment.

Effect of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and benzo[a]pyrene exposure on the development of metabolic syndrome in mice

AIM

The prevalence of metabolic syndrome (MetS), a cluster of serious medical conditions that raise the risk of lung cancer, has increased worldwide. Tobacco smoking (TS) potentially increases the risk of developing MetS. Despite the potential association of MetS with lung cancer, preclinical models that mimic human diseases, including TS-induced MetS, are limited. Here we evaluated the impact of exposure to tobacco smoke condensate (TSC) and two representative tobacco carcinogens, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNK) and benzo[a]pyrene (BaP), on MetS development in mice.

MATERIALS AND METHODS

FVB/N or C57BL/6 mice were exposed to vehicle, TSC, or NNK and BaP (NB) twice weekly for 5 months. The serum levels of total cholesterol (TCHO), triglycerides, high-density lipoprotein (HDL), blood glucose, and metabolites, along with glucose tolerance and body weight, were measured.

KEY FINDINGS

Compared with those of vehicle-treated mice, mice with TSC or NB exposure displayed major phenotypes associated with MetS, including increased serum levels of TCHO, triglycerides, and fasting and basal blood glucose and decreased glucose tolerance, and serum levels of HDL. These MetS-associated changes were found in both FVB/N and C57BL/6 mice that were susceptible or resistant to carcinogen-induced tumorigenesis, respectively, indicating that tumor formation is not involved in the TSC- or NB-mediated MetS. Moreover, oleic acid and palmitoleic acid, which are known to be associated with MetS, were significantly upregulated in the serum of TSC- or NB-treated mice compared with those in vehicle-treated mice.

SIGNIFICANCE

Both TSC and NB caused detrimental health problems, leading to the development of MetS in experimental mice.

Syntheses and antitumor activities of neorautenol and shinpterocarpin analogs

The natural products neorautenol and shinpterocarpin and their structural analogs were investigated as novel anticancer agents. Twenty-four analogs, including analogs containing a polar chain and simplified analogs, were synthesized efficiently by a modified method from previous reports. The antitumor screening of synthesized compounds toward six cancer cell lines indicated that compounds 37, 42 and 43 with a dialkylaminoethyl-type side chain exhibited more promising activity than neorautenol and shinpterocarpin against lung and colon cancer lines with a range of 4-9 μM. They showed selective toxicity in normal cells.

Korean Version of the Nursing Student Attitudes and Knowledge toward Lesbian, Gay, Bisexual, and Transgender Patients Scale

AIM

This study aimed to analyze the reliability and validity of a Korean version of the Nursing Student Attitudes and Knowledge Toward Lesbian, Gay, Bisexual, and Transgender Patients (K-NAKL) Scale, which measures health and heterosexual attitudes toward LGBT individuals.

BACKGROUND

Lesbian, gay, bisexual, and transgender (LGBT) individuals often face discrimination and a lack of care experience on the part of healthcare professionals.

INTRODUCTION

In South Korea, the current knowledge and attitude measurement tools for medical staff regarding LGBT individuals are limited, as they only focus on homosexuality and do not account for different sexual orientations.

METHODS

The participants were 217 nursing college students aged 18-25. The item-total correlations method and Cronbach's alpha coefficient were used to analyze internal consistency reliability. Face validity, content validity, construct validity, and criterion validity testing were conducted to establish scale validity. We made sure to follow STROBE guidelines when carrying out this research.

RESULTS

The K-NAKL is a culturally appropriate instrument used to measure the attitudes and knowledge of Korean nursing students when it comes to LGBT health.

DISCUSSION

As LGBT health is increasingly gaining social interest, the nursing education curriculum needs to produce culturally competent graduates to meet the health needs of this vulnerable and marginalized population. The current study contributes to that goal.

CONCLUSION

The K-NAKL is a valid and reliable tool with which to measure attitudes and knowledge regarding LGBT health among Korean nursing students.

IMPLICATIONS FOR NURSING

The K-NAKL can enable Korean nursing students to increase their knowledge and improve their attitudes when caring for the LGBT population.

IMPLICATIONS FOR NURSING POLICY AND HEALTH POLICY

The study highlights the importance of incorporating LGBT-related health education into nursing curricula and developing inclusive policies to improve the quality of care and health outcomes for LGBT individuals.

Dual Impact of IGF2 on Alveolar Stem Cell Function during Tobacco-Induced Injury Repair and Development of Pulmonary Emphysema and Cancer

Pulmonary emphysema is a destructive inflammatory disease primarily caused by cigarette smoking (CS). Recovery from CS-induced injury requires proper stem cell (SC) activities with a tightly controlled balance of proliferation and differentiation. Here we show that acute alveolar injury induced by two representative tobacco carcinogens, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and benzo[a]pyrene (N/B), increased IGF2 expression in alveolar type 2 (AT2) cells to promote their SC function and facilitate alveolar regeneration. Autocrine IGF2 signaling upregulated Wnt genes, particularly Wnt3, to stimulate AT2 proliferation and alveolar barrier regeneration after N/B-induced acute injury. In contrast, repetitive N/B exposure provoked sustained IGF2-Wnt signaling through DNMT3A-mediated epigenetic control of IGF2 expression, causing a proliferation/differentiation imbalance in AT2s and development of emphysema and cancer. Hypermethylation of the IGF2 promoter and overexpression of DNMT3A, IGF2, and the Wnt target gene AXIN2 were seen in the lungs of patients with CS-associated emphysema and cancer. Pharmacologic or genetic approaches targeting IGF2-Wnt signaling or DNMT prevented the development of N/B-induced pulmonary diseases. These findings support dual roles of AT2 cells, which can either stimulate alveolar repair or promote emphysema and cancer depending on IGF2 expression levels.

SIGNIFICANCE

IGF2-Wnt signaling plays a key role in AT2-mediated alveolar repair after cigarette smoking-induced injury but also drives pathogenesis of pulmonary emphysema and cancer when hyperactivated.

The tobacco-specific carcinogen NNK induces pulmonary tumorigenesis via nAChR/Src/STAT3-mediated activation of the renin-angiotensin system and IGF-1R signaling

The renin-angiotensin (RA) system has been implicated in lung tumorigenesis without detailed mechanistic elucidation. Here, we demonstrate that exposure to the representative tobacco-specific carcinogen nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) promotes lung tumorigenesis through deregulation of the pulmonary RA system. Mechanistically, NNK binding to the nicotinic acetylcholine receptor (nAChR) induces Src-mediated signal transducer and activator of transcription 3 (STAT3) activation, resulting in transcriptional upregulation of angiotensinogen (AGT) and subsequent induction of the angiotensin II (AngII) receptor type 1 (AGTR1) signaling pathway. In parallel, NNK concurrently increases insulin-like growth factor 2 (IGF2) production and activation of IGF-1R/insulin receptor (IR) signaling via a two-step pathway involving transcriptional upregulation of IGF2 through STAT3 activation and enhanced secretion from intracellular storage through AngII/AGTR1/PLC-intervened calcium release. NNK-mediated crosstalk between IGF-1R/IR and AGTR1 signaling promoted tumorigenic activity in lung epithelial and stromal cells. Lung tumorigenesis caused by NNK exposure or alveolar type 2 cell-specific Src activation was suppressed by heterozygous Agt knockout or clinically available inhibitors of the nAChR/Src or AngII/AGTR1 pathways. These results demonstrate that NNK-induced stimulation of the lung RA system leads to IGF2-mediated IGF-1R/IR signaling activation in lung epithelial and stromal cells, resulting in lung tumorigenesis in smokers.

Cellular Dormancy in Cancer - Mechanisms and Potential Targeting Strategies

Cancer is a leading cause of disease-related mortality worldwide. Drug resistance is one of the primary reasons for the failure of anticancer therapy. There are a number of underlying mechanisms for anticancer drug resistance including genetic/epigenetic modifications, microenvironmental factors, and tumor heterogeneity. In the present scenario, researchers have focused on these novel mechanisms and strategies to tackle them. Recently, researchers have recognized the ability of cancer to become dormant because of anticancer drug resistance, tumor relapse, and progression. Currently, cancer dormancy is classified into "tumor mass dormancy" and "cellular dormancy." Tumor mass dormancy represents the equilibrium between cell proliferation and cell death under the control of blood supply and immune responses. Cellular dormancy denotes the state in which cells undergo quiescence and is characterized by autophagy, stress-tolerance signaling, microenvironmental cues, and epigenetic modifications. Cancer dormancy has been regarded as the stem of primary or distal recurrent tumor formation and poor clinical outcomes in cancer patients. Despite the insufficiency of reliable models of cellular dormancy, the mechanisms underlying the regulation of cellular dormancy have been clarified in numerous studies. A better understanding of the biology of cancer dormancy is critical for the development of effective anticancer therapeutic strategies. In this review, we summarize the characteristics and regulatory mechanisms of cellular dormancy, introduce several potential strategies for targeting cellular dormancy, and discuss future perspectives.

An A-ring substituted evodiamine derivative with potent anticancer activity against human non-small cell lung cancer cells by targeting heat shock protein 70

The heat shock protein (HSP) system is essential for the conformational stability and function of several proteins. Therefore, the development of efficacious HSP-targeting anticancer agents with minimal toxicity is required. We previously demonstrated that evodiamine is an anticancer agent that targets HSP70 in non-small cell lung cancer (NSCLC) cells. In this study, we synthesized a series of evodiamine derivatives with improved efficacy and limited toxicity. Among the 14 evodiamine derivatives, EV408 (10-hydroxy-14-methyl-8,13,13b,14-tetrahydroindolo [2',3':3,4]pyrido[2,1-b]quinazolin-5(7H)-one) exhibited the most potent inhibitory effects on viability and colony formation under anchorage-dependent and -independent culture conditions in various human NSCLC cells, including those that are chemoresistant, by inducing apoptosis. In addition, EV408 suppressed the cancer stem-like cell (CSC) population of NSCLC cells and the expression of stemness-associated markers. Mechanistically, EV408 inhibited HSP70 function by directly binding and destabilizing the HSP70 protein. Furthermore, EV408 significantly inhibited the growth of NSCLC cell line tumor xenografts without overt toxicity. Additionally, EV408 had a negligible effect on the viability of normal cells. These results suggest the potential of EV408 as an efficacious HSP70-targeting evodiamine derivative with limited toxicity that inhibits both non-CSC and CSC populations in NSCLC.

Isolation of slow-cycling cancer cells from lung patient-derived xenograft using carboxyfluorescein-succinimidyl ester retention-mediated cell sorting

The slow-cycling subpopulation plays an important role in anticancer drug resistance and tumor recurrence. Here, we describe a clinically relevant patient-derived xenograft model and a carboxyfluorescein succinimidyl ester dye that is diluted in a cell proliferation-dependent manner. We detail steps to separate active-cycling cancer cells and slow-cycling cancer cells (SCCs) in heterogeneous cancer populations to confirm their different cellular properties. This protocol can be used to distinguish SCCs, investigate their biology, and develop strategies for anticancer therapeutics. For complete details on the use and execution of this protocol, please refer to Cho et al. (2021).¹.

S100A14: A novel negative regulator of cancer stemness and immune evasion by inhibiting STAT3-mediated programmed death-ligand 1 expression in colorectal cancer

Background

Programmed death‐ligand 1 (PD‐L1) has functional roles in cancer stem‐like cell (CSC) phenotypes and chemoresistance besides immune evasion. Chemotherapy is a common treatment choice for colorectal cancer (CRC) patients; however, chemoresistance limits its effectiveness of treatment.

Methods

We examined the role of S100A14 (SA14) in CRC by adopting PD‐L1^high subpopulations within CRC cell lines and patient tumours, by establishing PD‐L1^high chemoresistant CRC sublines through prolonged exposure to 5‐fluorouracil/oxaliplatin‐based chemotherapy in vitro and in vivo, and by analysing a public database.

Results

We identified a novel function of SA14 as a regulator of immune surveillance, major CSC phenotypes, and survival capacity under hostile microenvironments, including those harbouring chemotherapeutics, and as a prognostic biomarker in CRC. Mechanistically, SA14 inhibits PD‐L1 expression by directly interacting with signal transducer and activator of transcription 3 (STAT3) and inducing its proteasome‐mediated degradation. While gain‐of‐SA14 causes loss of PD‐L1 expression and tumourigenic potential and sensitisation to chemotherapy‐induced apoptosis in chemoresistant CRC cells, loss‐of‐SA14 causes increases in PD‐L1 expression, tumourigenic potential, and chemoresistance in vitro and in vivo. We further show that a combinatorial treatment with chemotherapy and recombinant SA14 protein effectively induces apoptosis in PD‐L1^high chemoresistant CRC cells.

Conclusions

Our results suggest that SA14‐based therapy is an effective strategy to prevent tumour progression and that SA14 is a predictive biomarker for anti‐PD‐L1 immunotherapy and chemotherapy in combination.

Targeting epidermal growth factor receptor in paclitaxel-resistant human breast and lung cancer cells with upregulated glucose-6-phosphate dehydrogenase

BACKGROUND

Chemoresistance is a major obstacle to the successful treatment of triple-negative breast cancer (TNBC) and non-small-cell lung cancer (NSCLC). Therapeutic strategies to overcome chemoresistance are necessary to improve the prognosis of patients with these cancers.

METHODS

Paclitaxel-resistant TNBC and NSCLC sublines were generated through continuous paclitaxel treatment over 6 months. The mechanistic investigation was conducted using MTT assay, LC/MS-based metabolite analysis, flow cytometry, western blot analysis, real-time PCR and tumour xenograft experiments.

RESULTS

Glucose-6-phosphate dehydrogenase (G6PD) expression along with an increase in 3-phosphoglycerates and ribulose-5-phosphate production was upregulated in paclitaxel-resistant cells. Blockade of G6PD decreased viability of paclitaxel-resistant cells in vitro and the growth of paclitaxel-resistant MDA/R xenograft tumours in vivo. Mechanistically, activation of the epidermal growth factor receptor (EGFR)/Akt pathway mediates G6PD expression and G6PD-induced cell survival. Blockade of the EGFR pathway inhibited G6PD expression and sensitised those paclitaxel-resistant cells to paclitaxel treatment in vitro and in vivo. Analysis of publicly available datasets revealed an association between G6PD and unfavourable clinical outcomes in patients with breast or lung cancer.

CONCLUSIONS

EGFR signaling-mediated G6PD expression plays a pivotal role in paclitaxel resistance, highlighting the potential of targeting EGFR to overcome paclitaxel resistance in TNBC and NSCLC cells overexpressing G6PD.

Ninjurin1 drives lung tumor formation and progression by potentiating Wnt/β-Catenin signaling through Frizzled2-LRP6 assembly

BACKGROUND

Cancer stem-like cells (CSCs) play a pivotal role in lung tumor formation and progression. Nerve injury-induced protein 1 (Ninjurin1, Ninj1) has been implicated in lung cancer; however, the pathological role of Ninj1 in the context of lung tumorigenesis remains largely unknown.

METHODS

The role of Ninj1 in the survival of non-small cell lung cancer (NSCLC) CSCs within microenvironments exhibiting hazardous conditions was assessed by utilizing patient tissues and transgenic mouse models where Ninj1 repression and oncogenic Kras^G12D/+ or carcinogen-induced genetic changes were induced in putative pulmonary stem cells (SCs). Additionally, NSCLC cell lines and primary cultures of patient-derived tumors, particularly Ninj1^high and Ninj1^low subpopulations and those with gain- or loss-of-Ninj1 expression, and also publicly available data were all used to assess the role of Ninj1 in lung tumorigenesis.

RESULTS

Ninj1 expression is elevated in various human NSCLC cell lines and tumors, and elevated expression of this protein can serve as a biomarker for poor prognosis in patients with NSCLC. Elevated Ninj1 expression in pulmonary SCs with oncogenic changes promotes lung tumor growth in mice. Ninj1^high subpopulations within NSCLC cell lines, patient-derived tumors, and NSCLC cells with gain-of-Ninj1 expression exhibited CSC-associated phenotypes and significantly enhanced survival capacities in vitro and in vivo in the presence of various cell death inducers. Mechanistically, Ninj1 forms an assembly with lipoprotein receptor-related protein 6 (LRP6) through its extracellular N-terminal domain and recruits Frizzled2 (FZD2) and various downstream signaling mediators, ultimately resulting in transcriptional upregulation of target genes of the LRP6/β-catenin signaling pathway.

CONCLUSIONS

Ninj1 may act as a driver of lung tumor formation and progression by protecting NSCLC CSCs from hostile microenvironments through ligand-independent activation of LRP6/β-catenin signaling.

A novel C-terminal heat shock protein 90 inhibitor that overcomes STAT3-Wnt-β-catenin signaling-mediated drug resistance and adverse effects

Rationale: The heat shock protein (Hsp) system plays important roles in cancer stem cell (CSC) and non-CSC populations. However, limited efficacy due to drug resistance and toxicity are obstacles to clinical use of Hsp90 inhibitors, suggesting the necessity to develop novel Hsp90 inhibitors overcoming these limitations. Methods: The underlying mechanism of resistance to Hsp90 inhibitors was investigated by colony formation assay, sphere formation assay, western blot analysis, and real-time PCR. To develop anticancer Hsp90 inhibitors that overcome the signal transducer and activator of transcription 3 (STAT3)-mediated resistance, we synthesized and screened a series of synthetic deguelin-based compounds in terms of inhibition of colony formation, migration, and viability of non-small cell lung cancer (NSCLC) cells and toxicity to normal cells. Regulation of Hsp90 by the selected compound NCT-80 [5-methoxy-N-(3-methoxy-4-(2-(pyridin-3-yl)ethoxy)phenyl)-2,2-dimethyl-2H-chromene-6-carboxamide] was investigated by immunoprecipitation, drug affinity responsive target stability assay, binding experiments using ATP-agarose beads and biotinylated drug, and docking analysis. The antitumor, antimetastatic, and anti-CSC effects of NCT-80 were examined in vitro and in vivo using various assays such as MTT, colony formation, and migration assays and flow cytometric analysis and tumor xenograft models. Results: We demonstrated a distinct mechanism in which Hsp90 inhibitors that block N-terminal ATP-binding pocket causes transcriptional upregulation of Wnt ligands through Akt- and ERK-mediated activation of STAT3, resulting in NSCLC cell survival in an autocrine or paracrine manner. In addition, NCT-80 effectively reduced viability, colony formation, migration, and CSC-like phenotypes of NSCLC cells and their sublines with acquired resistance to anticancer drugs by inducing apoptosis and inhibiting epithelial-mesenchymal transition and the growth of NSCLC patient-derived xenograft tumors without overt toxicity. With regards to mechanism, NCT-80 directly bound to the C-terminal ATP-binding pocket of Hsp90, disrupting the interaction between Hsp90 and STAT3 and degrading STAT3 protein. Moreover, NCT-80 inhibited chemotherapy- and EGFR TKI-induced programmed cell death ligand 1 expression and potentiated the antitumor effect of chemotherapy in the LLC-Luc allograft model. Conclusions: These data indicate the potential of STAT3/Wnt signaling pathway as a target to overcome resistance to Hsp90 inhibitors and NCT-80 as a novel Hsp90 inhibitor that targets both CSCs and non-CSCs in NSCLC.

RGS2-mediated translational control mediates cancer cell dormancy and tumor relapse

Slow-cycling/dormant cancer cells (SCCs) have pivotal roles in driving cancer relapse and drug resistance. A mechanistic explanation for cancer cell dormancy and therapeutic strategies targeting SCCs are necessary to improve patient prognosis, but are limited because of technical challenges to obtaining SCCs. Here, by applying proliferation-sensitive dyes and chemotherapeutics to non-small cell lung cancer (NSCLC) cell lines and patient-derived xenografts, we identified a distinct SCC subpopulation that resembled SCCs in patient tumors. These SCCs displayed major dormancy-like phenotypes and high survival capacity under hostile microenvironments through transcriptional upregulation of regulator of G protein signaling 2 (RGS2). Database analysis revealed RGS2 as a biomarker of retarded proliferation and poor prognosis in NSCLC. We showed that RGS2 caused prolonged translational arrest in SCCs through persistent eukaryotic initiation factor 2 (eIF2α) phosphorylation via proteasome-mediated degradation of activating transcription factor 4 (ATF4). Translational activation through RGS2 antagonism or the use of phosphodiesterase 5 inhibitors, including sildenafil (Viagra), promoted ER stress-induced apoptosis in SCCs in vitro and in vivo under stressed conditions, such as those induced by chemotherapy. Our results suggest that a low-dose chemotherapy and translation-instigating pharmacological intervention in combination is an effective strategy to prevent tumor progression in NSCLC patients after rigorous chemotherapy.

Development of the phenylpyrazolo[3,4-d]pyrimidine-based, insulin-like growth factor receptor/Src/AXL-targeting small molecule kinase inhibitor

Rationale: The type I insulin-like growth factor receptor (IGF-1R) signaling pathway plays key roles in the development and progression of numerous types of human cancers, and Src and AXL have been found to confer resistance to anti-IGF-1R therapies. Hence, co-targeting Src and AXL may be an effective strategy to overcome resistance to anti-IGF-1R therapies. However, pharmacologic targeting of these three kinases may result in enhanced toxicity. Therefore, the development of novel multitarget anticancer drugs that block IGF-1R, Src, and AXL is urgently needed.

Methods: We synthesized a series of phenylpyrazolo[3,4-d]pyrimidine (PP)-based compounds, wherein the PP module was conjugated with 2,4-bis-arylamino-1,3-pyrimidines (I2) via a copper(I)-catalyzed alkyne-azide cycloaddition reaction. To develop IGF-1R/Src/AXL-targeting small molecule kinase inhibitors, we selected LL6 as an active compound and evaluated its antitumor and antimetastatic effects in vitro and in vivo using the MTT assay, colony formation assays, migration assay, flow cytometric analysis, a tumor xenograft model, the Kras^G12D/+-driven spontaneous lung tumorigenesis model, and a spontaneous metastasis model using Lewis lung carcinoma (LLC) allografts. We also determined the toxicity of LL6 in vitro and in vivo.

Results: LL6 induced apoptosis and suppressed viability and colony-forming capacities of various non-small cell lung cancer (NSCLC) cell lines and their sublines with drug resistance. LL6 also suppressed the migration of NSCLC cells at nontoxic doses. Administration of LL6 in mice significantly suppressed the growth of NSCLC xenograft tumors and metastasis of LLC allograft tumors with outstanding toxicity profiles. Furthermore, the multiplicity, volume, and load of lung tumors in Kras^G12D/+ transgenic mice were substantially reduced by the LL6 treatment.

Conclusions: Our results show the potential of LL6 as a novel IGF-1R/Src/AXL-targeting small molecule kinase inhibitor, providing a new avenue for anticancer therapies.

Evodiamine inhibits both stem cell and non-stem-cell populations in human cancer cells by targeting heat shock protein 70

Rationale: Cancer stem cells (CSCs) are known to cause tumor recurrence and drug resistance. The heat shock protein (HSP) system plays a major role in preserving expression and function of numerous oncoproteins, including those involved in the CSC activities. We explored novel anticancer drugs, especially those targeting HSP components required for the functional role of CSCs.

Methods: Investigation of the role of the HSP system in CSCs and screening of a natural product chemical library were performed by utilizing cancer cell lines, primary cultures of patient-derived xenografts (PDXs), and their putative CSC subpopulations (i.e., those grown under sphere-forming conditions, stably transfected with reporter vectors carrying NANOG or POUSF1 promoters, or carrying high ALDH activity) in vitro and PDX and Kras^G12D/+-driven tumor models in vivo. Regulation of the HSP system was investigated by immunoprecipitation, drug affinity responsive target stability assay, binding experiments using ATP-agarose beads and biotinylated drug, and docking analysis.

Results: The HSP system was activated in CSCs via transcriptional upregulation of the HSP system components, especially HSP70. Evodiamine (Evo) was identified to induce apoptosis in both CSC and bulk non-CSC populations in human lung, colon, and breast cancer cells and their sublines with chemoresistance. Evo administration decreased the multiplicity, volume, and load of lung tumors in Kras^G12D/+ transgenic mice and the growth of cancer cell line- and PDX-derived tumors without detectable toxicity. Mechanistically, Evo disrupted the HSP system by binding the N-terminal ATP-binding pocket of HSP70 and causing its ubiquitin-mediated degradation.

Conclusions: Our findings illustrate HSP70 as a potential target for eliminating CSCs and Evo as an effective HSP70-targeting anticancer drug eradicating both CSCs and non-CSCs with a minimal toxicity.

LJ-2698, an Adenosine A3 Receptor Antagonist, Alleviates Elastase-Induced Pulmonary Emphysema in Mice

Emphysema, a major component of chronic obstructive pulmonary disease (COPD), is a leading cause of human death worldwide. The progressive deterioration of lung function that occurs in the disease is caused by chronic inflammation of the airway and destruction of the lung parenchyma. Despite the main impact of inflammation on the pathogenesis of emphysema, current therapeutic regimens mainly offer symptomatic relief and preservation of lung function with little therapeutic impact. In the present study, we aimed to discover novel therapeutics that suppress the pathogenesis of emphysema. Here, we show that LJ-2698, a novel and highly selective antagonist of the adenosine A₃ receptor, a G protein-coupled receptor involved in various inflammatory diseases, significantly reversed the elastase-induced destructive changes in murine lungs. We found that LJ-2698 significantly prevented elastase-induced airspace enlargement, resulting in restoration of pulmonary function without causing any obvious changes in body weight in mice. LJ-2698 was found to inhibit matrix metalloproteinase activity and pulmonary cell apoptosis in the murine lung. LJ-2698 treatment induced increases in anti-inflammatory cytokines in macrophages at doses that displayed no significant cytotoxicity in normal cell lines derived from various organs. Treatment with LJ-2698 significantly increased the number of anti-inflammatory M2 macrophages in the lungs. These results implicate the adenosine A₃ receptor in the pathogenesis of emphysema. Our findings also demonstrate the potential of LJ-2698 as a novel therapeutic/preventive agent in suppressing disease development with limited toxicity.

The Interplay between Slow-Cycling, Chemoresistant Cancer Cells and Fibroblasts Creates a Proinflammatory Niche for Tumor Progression

Quiescent cancer cells are believed to cause cancer progression after chemotherapy through unknown mechanisms. We show here that human non-small cell lung cancer (NSCLC) cell line-derived, quiescent-like, slow-cycling cancer cells (SCC) and residual patient-derived xenograft (PDX) tumors after chemotherapy experience activating transcription factor 6 (ATF6)-mediated upregulation of various cytokines, which acts in a paracrine manner to recruit fibroblasts. Cancer-associated fibroblasts (CAF) underwent transcriptional upregulation of COX2 and type I collagen (Col-I), which subsequently triggered a slow-to-active cycling switch in SCC through prostaglandin E₂ (PGE₂)- and integrin/Src-mediated signaling pathways, leading to cancer progression. Both antagonism of ATF6 and cotargeting of Src/COX2 effectively suppressed cytokine production and slow-to-active cell cycling transition in SCC, withholding cancer progression. Expression of COX2 and Col-I and activation of Src were observed in patients with NSCLC who progressed while receiving chemotherapy. Public data analysis revealed significant association between COL1A1 and SRC expression and NSCLC relapse. Overall, these findings indicate that a proinflammatory niche created by the interplay between SCC and CAF triggers tumor progression. SIGNIFICANCE: Cotargeting COX2 and Src may be an effective strategy to prevent cancer progression after chemotherapy.

Papuamine Inhibits Viability of Non-small Cell Lung Cancer Cells by Inducing Mitochondrial Dysfunction

BACKGROUND/AIM

Despite the Warburg effect, mitochondria play an essential role in the survival and maintenance of cancer cells. Thus, mitochondria have been considered a target for anticancer agents. Here, we identified a mitochondria-targeting anticancer agent from natural products.

MATERIALS AND METHODS

Morphological and functional changes in mitochondria were determined by a fluorescence-based High Content Imaging System. Using human non-small cell lung cancer (NSCLC) cell lines (H1299, H226B, and A549), cell viability and colony formation assays, cell cycle analysis, and immunoblotting were performed to determine cytotoxic and proapoptotic effects of papuamine.

RESULTS

Using a natural product chemical library, we identified papuamine as an active compound to inhibit viability and ATP production of NSCLC cells. Papuamine depleted intracellular ATP by causing mitochondrial dysfunction, as indicated by the loss of the mitochondrial membrane potential and increased mitochondrial superoxide generation. Papuamine significantly inhibited viability and colony formation of NSCLC cells by inducing apoptosis.

CONCLUSION

Papuamine has a potential as a novel mitochondria-targeting anticancer agent.

The natural compound gracillin exerts potent antitumor activity by targeting mitochondrial complex II

Mitochondria play a pivotal role in cancer bioenergetics and are considered a potential target for anticancer therapy. Considering the limited efficacy and toxicity of currently available mitochondria-targeting agents, it is necessary to develop effective mitochondria-targeting anticancer drugs. By screening a large chemical library consisting of natural products with diverse chemical entities, we identified gracillin, a steroidal saponin, as a mitochondria-targeting antitumor drug. Gracillin displayed broad-spectrum inhibitory effects on the viability of a large panel of human cancer cell lines, including those carrying acquired resistance to chemotherapy or EGFR-targeting drugs, by inducing apoptosis. We show that gracillin attenuates mitochondria-mediated cellular bioenergetics by suppressing ATP synthesis and by producing reactive oxygen species (ROS). Mechanistically, gracillin disrupts complex II (CII) function by abrogating succinate dehydrogenase (SDH) activity without affecting the succinate:ubiquinone reductase. The gracillin-induced cell death was potentiated by 3-nitropropionic acid (3-NPA) or thenoyltrifluoroacetone (TTFA), which inhibit CII by binding to the active site of SDHA or to the ubiquinone-binding site, respectively. Finally, we show that gracillin effectively suppressed the mutant-Kras-driven lung tumorigenesis and the growth of xenograft tumors derived from cell lines or patient tissues. Gracillin displayed no obvious pathophysiological features in mice. Collectively, gracillin has potential as a CII-targeting antitumor drug.

Abstract 1862: Natural compound E targets both lung cancer stem and non-cancer stem cells by disrupting HSP70 function

Solid malignant tumors are composed of heterogeneous populations of cancer cell, including cancer stem-like cells (CSCs), a specialized cell population characterized by the functional properties of self-renewal and have a potential to differentiate into various cancer subtypes. CSCs contribute to tumor recurrence, metastasis, and drug resistance, affecting efficacy of anticancer therapies. However, treatment strategies specifically targeting CSCs are limited, because current chemotherapeutic drugs mainly kill the bulk of sensitive cancer cells, leaving behind CSCs. These remaining CSCs are the main cause of cancer relapse and drug resistance. Hence, development of novel compounds eradicating CSCs are crucial for effective anticancer therapies. To identify novel CSC-targeting anticancer drugs, we have set-up a reporter system based on promoter activities of CSC markers that allows a standardized identification of CSCs. By using the reporter system, we screened a large natural products chemical library consisting 452 compounds with diverse chemical entity. And we selected 4 compounds. To further assess the inhibitory effect of these 4 compounds, we used sphere-forming assay with NSCLC cell lines. Through these processes, we finally chose Compound E. We found that treatment with Compound E significantly reduced the subpopulation of NSCLC CSC. We confirmed the inhibitory effects of Compound E on NSCLC CSCs by performing sphere formation analysis and flow cytometry-based ALDH detection assay. Treatment with Compound E also suppressed the viability and colony-forming abilities of NSCLC cells (non-CSCs) and their sublines carrying acquired chemoresistance by inducing apoptosis. In line with these in vitro results, orally administered Compound E significantly suppressed the growth of xenograft tumors derived from both NSCLC cell lines and patient-derived tumor tissues. To determine the tumor forming capacity of tumor cells derived from the vehicle or Compound E-treated mice, we carried out a limiting dilution tumor-propagating assay. NOD/SCID mice were transplanted with tumor cells over a range from doses unable to initiate tumor growth to dose that initiated tumor formation. Tumor cells derived from Compound E-treated mice displayed reduced tumor forming capacity compared to vehicle treated mice. Mechanistically, Compound E disrupted Hsp70 function by binding to the ATP-binding pockets of Hsp70. These data collectively unveil the potential of Compound E as a natural Hsp70 inhibitor targeting both CSC and non-CSC populations of NSCLC.

Citation Format: Seung Yeob Hyun, Huong Thuy Le, HongLan Pei, Simin Chun, Hye-Young Min, Suckchang Hong, Ho-Young Lee. Natural compound E targets both lung cancer stem and non-cancer stem cells by disrupting HSP70 function [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1862.

Abstract 4806: Development of a novel antitumor agent NCT compound for the treatment of non-small cell lung cancer

Despite the development of advanced therapeutic regimens such as molecular targeted therapy and immunotherapy, the 5-year survival of patients with lung cancer is still less than 20%, suggesting the need to develop additional treatment strategies. Here we show the efficacy and biological mechanism of a novel antitumor agent, NCT compound. NCT compound exhibited significant inhibitory effects on the viability and colony formation of non-small cell lung cancer (NSCLC) cells and those carrying resistance to chemotherapy by inducing apoptosis. NCT compound markedly suppressed the migration of NSCLC cells. Consistently, NCT compound significantly suppressed tumor growth in a xenograft model. NCT compound showed minimal effects on the viability of normal cells and no overt toxic effects in mice, suggesting minimal toxicity of NCT compound. Further mechanistic studies revealed that NCT compound downregulated the activation of signaling pathway associated with cell proliferation and survival and the expression of epithelial-mesenchymal transition (EMT)-related markers. These results suggest the potential of NCT compound as an antitumor agent.

Citation Format: Seung Yeob Hyun, Huong Thuy Le, Young-Sik Yong, Hye-Young Min, Jeewoo Lee, Ho-Young Lee. Development of a novel antitumor agent NCT compound for the treatment of non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4806.

Development of a novel Hsp90 inhibitor NCT-50 as a potential anticancer agent for the treatment of non-small cell lung cancer

Despite the development of advanced therapeutic regimens such as molecular targeted therapy and immunotherapy, the 5-year survival of patients with lung cancer is still less than 20%, suggesting the need to develop additional treatment strategies. The molecular chaperone heat shock protein 90 (Hsp90) plays important roles in the maturation of oncogenic proteins and thus has been considered as an anticancer therapeutic target. Here we show the efficacy and biological mechanism of a Hsp90 inhibitor NCT-50, a novobiocin-deguelin analog hybridizing the pharmacophores of these known Hsp90 inhibitors. NCT-50 exhibited significant inhibitory effects on the viability and colony formation of non-small cell lung cancer (NSCLC) cells and those carrying resistance to chemotherapy. In contrast, NCT-50 showed minimal effects on the viability of normal cells. NCT-50 induced apoptosis in NSCLC cells, inhibited the expression and activity of several Hsp90 clients including hypoxia-inducible factor (HIF)-1α, and suppressed pro-angiogenic effects of NSCLC cells. Further biochemical and in silico studies revealed that NCT-50 downregulated Hsp90 function by interacting with the C-terminal ATP-binding pocket of Hsp90, leading to decrease in the interaction with Hsp90 client proteins. These results suggest the potential of NCT-50 as an anticancer Hsp90 inhibitor.

Erybraedin A is a potential Src inhibitor that blocks the adhesion and viability of non-small-cell lung cancer cells

The adhesion of cancer cells to the extracellular matrix (ECM) is crucial for cell proliferation, survival, and metastasis. Thus, it is necessary to inhibit cell-ECM adhesion by blocking the activation of the associated signaling to control cancer. Here, we identify erybraedin A (EBA) as a potential Src inhibitor that blocks cell adhesion and viability in non-small-cell lung cancer (NSCLC). EBA significantly inhibited the adhesion of NSCLC cells to fibronectin. EBA also markedly inhibited the activation of Src and its downstream targets, including FAK and Akt. The interaction between integrin β1 or integrin β3 and Src was inhibited by EBA treatment. A docking study revealed the bindings of EBA to the ATP-binding pocket and the allosteric regulatory site of the Src kinase. Additionally, EBA markedly inhibited the viability and the colony formation of NSCLC cells and induced apoptotic cell death. These results describe novel biological properties of EBA, which can block the Src-mediated adhesion and survival of NSCLC cells, suggesting the potential of EBA as an anticancer Src inhibitor that warrants further development in advanced preclinical and clinical settings.

Abstract 2677: A natural product-derived Compound A effectively targets both cancer stem and non-stem cells in NSCLC

Cancer stem-like cells (CSCs) contribute to tumor recurrence and chemoresistance. Hence, strategies eradicating CSCs are crucial for effective anticancer therapies. Here, we demonstrate transcriptional upregulation of the heat shock proteins (Hsp90 and Hsp70) and their co-chaperones and enhanced activities of the Hsp system in both non-CSCs and CSCs in non-small cell lung cancer (NSCLC) cells. Genetic and pharmacologic strategies targeting Hsps eliminated both CSCs and non-CSCs of NSCLC, suggesting the functional role of the Hsp system in the two populations in NSCLC. We further identified Compound A, a natural product-derived compound, as a novel Hsp70 inhibitor eliminating both the CSC and non-CSC populations in NSCLC. Compound A inhibited the sphere-forming ability of NSCLC CSCs by inducing apoptosis. Compound A also suppressed the viability and colony-forming abilities of NSCLC cells (non-CSCs) and their sublines carrying acquired chemoresistance by inducing apoptosis with minimal toxicity in normal cells derived from various organs. Mechanistically, Compound A disrupted Hsp70 function by binding to the ATP-binding pockets of Hsp70. These data suggest the rationale to target the Hsp system for controlling both CSCs and non-CSCs in NSCLC and the potential of Compound A as a natural Hsp70 inhibitor to eliminate the two populations with limited toxicities.

Citation Format: Seung Yeob Hyun, Huong T. Le, Jaebeom Cho, Hye-Young Min, Ho-Young Lee. A natural product-derived Compound A effectively targets both cancer stem and non-stem cells 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 2677.

Abstract 2950: Development of a 4-aminopyrazolo[3,4-d]pyrimidine-based dual IGF1R/Src inhibitor as a novel anticancer agent with minimal toxicity

Both the type I insulin-like growth factor receptor (IGF1R) and Src pathways are associated with the development and progression of numerous types of human cancer, and Src activation confers resistance to anti-IGF1R therapies. Hence, targeting both IGF1R and Src concurrently is one of the main challenges in combating resistance to the currently available anti-IGF1R-based anticancer therapies. However, the enhanced toxicity from this combinatorial treatment could be one of the main hurdle for this strategy, suggesting the necessity of developing a novel strategy for co-targeting IGF1R and Src to meet an urgent clinical need. In the present study, We synthesized a series of 4-aminopyrazolo[3,4-d]pyrimidine-based dual IGF1R/Src inhibitors, selected LL28 as an active compound, and evaluated its potential antitumor effects in vitro and in vivo. LL28 markedly suppressed the activation of IGF1R and Src and significantly inhibited the viability of several NSCLC cell lines in vitro by inducing apoptosis. Administration of mice with LL28 significantly suppressed the growth of H1299 NSCLC xenograft tumors without overt toxicity and substantially reduced the multiplicity, volume, and load of lung tumors in the KrasG12D/+-driven lung tumorigenesis model. These results suggest the potential of LL28 as a novel anticancer drug candidate targeting both IGF1R and Src, providing a new avenue to efficient anticancer therapies. Further investigation is warranted in advanced preclinical and clinical settings.

Citation Format: Ho-Jin Lee, Hye-Young Min, Phuong Chi Pham, Byungyeob Baek, Byungjin Kim, Yunha Kim, Jeeyeon Lee, Ho-Young Lee. Development of a 4-aminopyrazolo[3,4-d]pyrimidine-based dual IGF1R/Src inhibitor as a novel anticancer agent with minimal toxicity [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 2950.

Development of a 4-aminopyrazolo[3,4-d]pyrimidine-based dual IGF1R/Src inhibitor as a novel anticancer agent with minimal toxicity

BACKGROUND

Both the type I insulin-like growth factor receptor (IGF1R) and Src pathways are associated with the development and progression of numerous types of human cancer, and Src activation confers resistance to anti-IGF1R therapies. Hence, targeting both IGF1R and Src concurrently is one of the main challenges in combating resistance to the currently available anti-IGF1R-based anticancer therapies. However, the enhanced toxicity from this combinatorial treatment could be one of the main hurdles for this strategy, suggesting the necessity of developing a novel strategy for co-targeting IGF1R and Src to meet an urgent clinical need.

METHODS

We synthesized a series of 4-aminopyrazolo[3,4-d]pyrimidine-based dual IGF1R/Src inhibitors, selected LL28 as an active compound and evaluated its potential antitumor effects in vitro and in vivo using the MTT assay, colony formation assays, flow cytometric analysis, a tumor xenograft model, and the Kras ^G12D/+ -driven spontaneous lung tumorigenesis model.

RESULTS

LL28 markedly suppressed the activation of IGF1R and Src and significantly inhibited the viability of several NSCLC cell lines in vitro by inducing apoptosis. Administration of mice with LL28 significantly suppressed the growth of H1299 NSCLC xenograft tumors without overt toxicity and substantially reduced the multiplicity, volume, and load of lung tumors in the Kras ^G12D/+ -driven lung tumorigenesis model.

CONCLUSIONS

The present results suggest the potential of LL28 as a novel anticancer drug candidate targeting both IGF1R and Src, providing a new avenue to efficient anticancer therapies. Further investigation is warranted in advanced preclinical and clinical settings.

Oncogene-Driven Metabolic Alterations in Cancer

Cancer is the leading cause of human deaths worldwide. Understanding the biology underlying the evolution of cancer is important for reducing the economic and social burden of cancer. In addition to genetic aberrations, recent studies demonstrate metabolic rewiring, such as aerobic glycolysis, glutamine dependency, accumulation of intermediates of glycolysis, and upregulation of lipid and amino acid synthesis, in several types of cancer to support their high demands on nutrients for building blocks and energy production. Moreover, oncogenic mutations are known to be associated with metabolic reprogramming in cancer, and these overall changes collectively influence tumor-microenvironment interactions and cancer progression. Accordingly, several agents targeting metabolic alterations in cancer have been extensively evaluated in preclinical and clinical settings. Additionally, metabolic reprogramming is considered a novel target to control cancers harboring un-targetable oncogenic alterations such as KRAS. Focusing on lung cancer, here, we highlight recent findings regarding metabolic rewiring in cancer, its association with oncogenic alterations, and therapeutic strategies to control deregulated metabolism in cancer.

Abstract 3188: ER-stress induced translational regulation by RGS2 leads to tumor-promoting microenvironment and chemoresistance

Lung cancer is the leading cause of the cancer-related death worldwide. Despite extensive efforts for the cure of lung cancer, the effectiveness of currently available therapeutic regimens has been marginal and limited, and recurrence is still an inevitable consequence of anticancer therapies. Therefore, mechanistic understanding on the progression and relapse of lung cancer and finding out relevant targets are essential for development of efficacious therapeutic strategies. We have investigated mechanisms of chemoresistance by using subsets of lung cancer cell lines carrying acquired resistance to chemotherapies. These chemoresistant sublines of NSCLC cells exhibited a prominent downregulation of in vitro tumor activities, including proliferation, metabolism, and protein synthesis, but displayed increased tumor growth in vivo. Additional studies revealed that the chemoresistant sublines experienced increased secretion of various soluble factors that led to increases in proliferation and stemness of drug-naïve cancer cells and recruitment of macrophages, establishing tumor microenvironment (TME) prone to tumor recurrence. We further demonstrate a pivotal role of regulator of G protein signaling 2 (RGS2) in tumor-promoting cell-cell communications, ultimately leading to chemoresistance. RGS2 disrupted chemotherapy-induced apoptosis and secretion of soluble factors involved in cellular communications in TME by regulating unfolded protein responses, a typical cellular event associated with downregulation of protein synthesis. Mechanistically, RGS2 induced proteasome-mediated protein degradation of a component of eukaryotic translation initiation factor complexes through direct interaction, resulting in blockade of the CAP-dependent protein translation. RGS2 expression was elevated in tumors derived from patients with lung cancer compared with normal counterparts and significantly associated with poor clinical outcomes. These findings suggest that RGS2 is a novel biomarker responsible for chemoresistance by establishing tumor-promoting TME and can be a potential therapeutic target for the treatment of lung cancer with chemoresistance.

Citation Format: Hye-Young Min, Shin-Hyung Park, Ho Jin Lee, Jaebeom Cho, Myungkyung Noh, Seung Yeob Hyun, Ho-Young Lee. ER-stress induced translational regulation by RGS2 leads to tumor-promoting microenvironment and chemoresistance [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 3188. doi:10.1158/1538-7445.AM2017-3188

Abstract 4780: Crucial role of S100A14 in blocking cancer stem cells and sensitizing to chemotherapy through STAT3 destabilization in human colorectal cancer

Colorectal cancer (CRC) is a major type of human cancers in terms of incidence and mortality worldwide. Chemotherapy is one of the standard protocols for the treatment of CRC but drug resistance is recognized as the main cause of treatment failure. Resistance to anticancer therapy is a multifactorial event involving a number of interrelated or independent mechanisms. Growing evidence supports a critical role of cancer stem cell (CSC) in development, progression, and resistance to anticancer therapies in CRCs. However, the molecular and cellular mechanisms underlying the CSC's chemoresistance are not completely defined, and a comprehensive understanding of the biology of the CSCs is urgently needed. We have investigated mechanisms of chemoresistance, focusing on those mediated by CSCs, through the employment of CRC stem-like cell populations that are: 1) sorted out by using well-characterized stemness markers; ii) established via serial passage through increasing doses of oxaliplatin or 5-FU; or iii) enriched by culturing in sphere forming condition. We then assessed changes involved in CSC maintenance and found a novel role of S100A14 in CSCs of CRC. We found that transcriptional down-regulations of S100A14 expression conferred phenotypes of CSCs in the stem-like cell populations of CRC. Consistently, elevation of S100A14 expression sensitized the stem-like cell populations to the treatment with 5-FU in vitro and in vivo. Mechanistically, S100A14 directly interacted with STAT3 and promoted its degradation via the ubiquitin-proteasome pathway, leading to decreases in STAT3 target gene expression and colony forming capacity of the stem-like cell populations. Further, S100A14 expression was markedly downregulated in human CRC tissue specimens compared with their normal counterparts. Moreover, the expression level of S100A14 was inversely correlated with clinical outcomes in patients with CRC. These results collectively suggest that S100A14 is a novel target for the treatment of colorectal cancer by targeting CSCs.

Citation Format: Jaebeom Cho, Hye-Young Min, Ji-Sun Lee, Ho-Young Lee. Crucial role of S100A14 in blocking cancer stem cells and sensitizing to chemotherapy through STAT3 destabilization in human colorectal cancer [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 4780. doi:10.1158/1538-7445.AM2017-4780

Essential Role of DNA Methyltransferase 1-mediated Transcription of Insulin-like Growth Factor 2 in Resistance to Histone Deacetylase Inhibitors

Purpose: Histone deacetylase inhibitors (HDI) are promising anticancer therapies; however, drug resistance limits their efficacy. Here, we investigated the molecular mechanisms underlying HDI resistance, focusing on the mechanism of HDI-mediated induction of insulin-like growth factor 2 (IGF2) based on our previous study.Experimental Design: The methylation status of CCCTC-binding factor (CTCF)-binding sites in the IGF2/H19 imprinting control region (ICR) were determined by methylation-specific PCR and bisulfite sequencing. The effectiveness of single or combinatorial blockade of DNA methyltransferase 1 (DNMT1) and histone deacetylase (HDAC) was evaluated using cell viability assay and patient-derived tumor xenograft (PDX) model.Results: HDAC inhibition by vorinostat increased acetylated STAT3 (K685), resulting in transcriptional upregulation of DNMT1 DNMT1-mediated hypermethylation of CTCF-binding sites in the IGF2/H19 ICR decreased CTCF insulator activity, leading to a transcriptional upregulation of IGF2 and activation of the insulin-like growth factor 1 receptor (IGF-1R) pathway in cells with acquired or de novo vorinostat resistance. Strategies targeting DNMT1 diminished the IGF2 expression and potentiated vorinostat sensitivity in preclinical models of lung cancer with hypermethylation in the H19/IGF2 ICR. The degree of ICR hypermethylation correlated with vorinostat resistance in patient-derived lung tumors and in patients with hematologic malignancies.Conclusions: DNMT1-mediated transcriptional upregulation of IGF2 is a novel mechanism of resistance to HDIs, highlighting the role of epigenetic deregulation of IGF2 in HDI resistance and the potential value of the H19/IGF2 ICR hypermethylation and DNMT1 expression as predictive biomarkers in HDI-based anticancer therapies. Clin Cancer Res; 23(5); 1299-311. ©2016 AACR.

Acquired resistance to 5-fluorouracil via HSP90/Src-mediated increase in thymidylate synthase expression in colon cancer

5-fluorouracil (5-FU), one of the first-line chemotherapeutic agents for the treatment of gastrointestinal malignancies, has shown limited efficacy. The expression of thymidylate synthase (TYMS) has been reported to be associated with the resistance to 5-FU. Here, we demonstrate that the enhanced HSP90 function and subsequent activation of Src induce expression of TYMS and acquired resistance to 5-FU in colon cancer. We show that the persistent 5-FU treatment granted 5-FU-sensitive HCT116 colon cancer cells morphologic, molecular, and behavioral characteristic of the epithelial-mesenchymal transition (EMT), contributing to emergence of acquired resistance to 5-FU. HCT116/R, a HCT116 colon cancer cell subline carrying acquired resistance to 5-FU, showed increased expression and activation of HSP90's client proteins and transcriptional up-regulation of TYMS. Forced overexpression of HSP90 or constitutive active Src in HCT116 cells increased TYMS expression. Conversely, pharmacological blockade of HSP90 or Src in HCT116/R cells effectively suppressed the changes involved in 5-FU resistance in vitro and xenograft tumor growth, hematogenous spread, and metastatic tumor development in vivo. This study suggests a novel function of HSP90-Src pathway in regulation of TYMS expression and acquisition of 5-FU resistance. Thus, therapeutics targeting this pathway may be an effective clinical strategy to overcome 5-FU resistance in colon cancer.

Abstract 2711: Regulation of the IGF-1R signaling by angiotensin signaling pathway

Lung cancer is one of the most commonly diagnosed cancers in the world. Tobacco smoking is the most predominant risk factor for the development of lung cancer. Carcinogenic compounds in tobacco smoke are thought to be responsible for lung cancer, at least in part, by activating G-protein coupled receptor (GPCR)-mediated signaling pathways. GPCR signaling has been suggested to cross-talk with the IGF-1R signaling pathway, a key pathway for cell survival, transformation and growth. However, the mechanisms underlying the crosstalk between GPCR and IGF-1R signaling pathways remain poorly understood. Here we show that tobacco carcinogen (TC) contributes to the lung carcinogenesis by activating the angiotensin signaling and subsequent IGF-1R signaling pathways. We observed that a potent tobacco carcinogen, nitrosamine 4-(methylnitro-samino)-1-(3-pyridyl)-1-butanone (NNK, nicotine-derived nitrosamine ketone), induced transformed phenotypes, including foci formation, viability in the absence of growth factors, and anchorage-dependent and -independent colony formation, and activation of the IGF-1R in normal human bronchial epithelial cells. The NNK treatment also induced lung tumor formation in mice. Losartan, an angiotensin type-1 receptor blocker, and captopril, an angiotensin converting enzyme (ACE) inhibitor, disrupted NNK-induced IGF-1R activation and transformed phenotypes in normal human bronchial epithelial cells and reduced lung tumor formation in mice. These findings indicated that TC-induced angiotensin signaling pathway can enhance lung carcinogenesis by activating the IGF-1R signaling. Our results suggest that targeting IGF-1R by using angiotensin signaling inhibitors may be an effective strategy for the chemoprevention of lung cancer.

Citation Format: Hye-Jin Boo, Hyun-Ji Jang, Yujin Jung, Hye-Young Min, Ho-Young Lee. Regulation of the IGF-1R signaling by angiotensin signaling pathway. [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 2711. doi:10.1158/1538-7445.AM2015-2711

Abstract 2729: Chronic stress promotes lung cancer development via IGF-1R pathway

Lung cancer is a leading cause of cancer death worldwide. Although smoking is a main cause, approximately 25% of lung cancer cases are not attributable to tobacco use. Epidemiological studies strongly suggest that chronic stress influences cancer development and progression. Recent mechanistic studies showed that biological signaling pathways could contribute to such effects. But the underlying mechanisms for the association between chronic stress and lung cancer development are poorly understood. The purpose of this study is to investigate whether chronic stress can induce lung cancer development and, if so, what is the mechanism underlying the chronic stress-induced lung cancer development. We observed that stress hormone, norepinephrine (NE) increased cell viability in the absence of growth factors, foci formation, and colony formation in human bronchial epithelial cells and activated the type 1 insulin-like growth factor receptor (IGF-1R) pathway. We found that chronic stress resulted in high levels of NE in serum, activation of IGF-1R in lung tissue and promoted urethane-induced lung tumor formation in vivo. Moreover, inhibition of the IGF-1R pathway suppressed NE-induced transformed phenotypes in vitro. We further confirmed that chronic stress-induced lung tumor formation was greater in mice carrying lung-specific human IGF-1R transgene (Tg) than in wild type mice. Our results indicate that chronic stress may promote lung cancer development via the IGF-1R pathway, suggesting that IGF-1R is an effective target for the chemoprevention of stress-induced lung cancer.

Citation Format: Hyun-Ji Jang, Hye-Jin Boo, Yujin Jung, Hye-Young Min, Ho-Young Lee. Chronic stress promotes lung cancer development via IGF-1R pathway. [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 2729. doi:10.1158/1538-7445.AM2015-2729

Targeting the insulin-like growth factor receptor and Src signaling network for the treatment of non-small cell lung cancer

Background

Therapeutic interventions in the insulin-like growth factor receptor (IGF-1R) pathway were expected to provide clinical benefits; however, IGF-1R tyrosine kinase inhibitors (TKIs) have shown limited antitumor efficacy, and the mechanisms conveying resistance to these agents remain elusive.

Methods

The expression and activation of the IGF-1R and Src were assessed via the analysis of a publicly available dataset, as well as immunohistochemistry, Western blotting, RT-PCR, and in vitro kinase assays. The efficacy of IGF-1R TKIs alone or in combination with Src inhibitors was analyzed using MTT assays, colony formation assays, flow cytometric analysis, and xenograft tumor models.

Results

The co-activation of IGF-1R and Src was observed in multiple human NSCLC cell lines as well as in a tissue microarray (n = 353). The IGF-1R and Src proteins mutually phosphorylate on their autophosphorylation sites. In high-pSrc-expressing NSCLC cells, linsitinib treatment initially inactivated the IGF-1R pathway but led a Src-dependent reactivation of downstream effectors. In low-pSrc-expressing NSCLC cells, linsitinib treatment decreased the turnover of the IGF-1R and Src proteins, ultimately amplifying the reciprocal co-activation of IGF-1R and Src. Co-targeting IGF-1R and Src significantly suppressed the proliferation and tumor growth of both high-pSrc-expressing and low-pSrc-expressing NSCLC cells in vitro and in vivo and the growth of patient-derived tissues in vivo.

Conclusions

Reciprocal activation between Src and IGF-1R occurs in NSCLC. Src causes IGF-1R TKI resistance by acting as a key downstream modulator of the cross-talk between multiple membrane receptors. Targeting Src is a clinically applicable strategy to overcome resistance to IGF-1R TKIs.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0392-3) contains supplementary material, which is available to authorized users.

Synthesis and Evaluation of a Novel Deguelin Derivative, L80, which Disrupts ATP Binding to the C-terminal Domain of Heat Shock Protein 90

The clinical benefit of current anticancer regimens for lung cancer therapy is still limited due to moderate efficacy, drug resistance, and recurrence. Therefore, the development of effective anticancer drugs for first-line therapy and for optimal second-line treatment is necessary. Because the 90-kDa molecular chaperone heat shock protein (Hsp90) contributes to the maturation of numerous mutated or overexpressed oncogenic proteins, targeting Hsp90 may offer an effective anticancer therapy. Here, we investigated antitumor activities and toxicity of a novel deguelin-derived C-terminal Hsp90 inhibitor, designated L80. L80 displayed significant inhibitory effects on the viability, colony formation, angiogenesis-stimulating activity, migration, and invasion of a panel of non-small cell lung cancer cell lines and their sublines with acquired resistance to paclitaxel with minimal toxicity to normal lung epithelial cells, hippocampal cells, vascular endothelial cells, and ocular cells. Biochemical analyses and molecular docking simulation revealed that L80 disrupted Hsp90 function by binding to the C-terminal ATP-binding pocket of Hsp90, leading to the disruption of the interaction between hypoxia-inducible factor (HIF)-1α and Hsp90, downregulation of HIF-1α and its target genes, including vascular endothelial growth factor (VEGF) and insulin-like growth factor 2 (IGF2), and decreased the expression of various Hsp90 client proteins. Consistent with these in vitro findings, L80 exhibited significant antitumor and antiangiogenic activities in H1299 xenograft tumors. These results suggest that L80 represents a novel C-terminal Hsp90 inhibitor with effective anticancer activities with minimal toxicities.

Activation of insulin-like growth factor receptor signaling mediates resistance to histone deacetylase inhibitors

Histone deacetylases (HDACs) are considered promising targets in the treatment of hematologic malignancies and several types of solid tumors, including non-small cell lung cancer (NSCLC). However, the efficacy of HDAC inhibitors in solid tumors is marginal, and the mechanisms underlying resistance to HDAC inhibitors are largely unknown. Here, we demonstrate the involvement of type 1 insulin-like growth factor receptor (IGF-1R) signaling in resistance to HDAC inhibitors in NSCLC. Using MTT and soft-agar colony formation assays, we selected NSCLC cell lines that exhibited intrinsic resistance to vorinostat. Treatment with vorinostat activated IGF-1R signaling in vorinostat-resistant but not vorinostat-sensitive NSCLC cells. Other HDAC inhibitors, including trichostatin A, sodium butyrate, and depsipeptide, also activated IGF-1R signaling in vorinostat-resistant NSCLC cells. Blockade of IGF-1R signaling via IGF-1R monoclonal antibodies (mAbs) or through knockdown of IGF-1R via RNA interference sensitized vorinostat-resistant cells to HDAC inhibition. Finally, IGF-1R mAbs sensitized xenograft tumors of vorinostat-resistant cells to vorinostat treatment in vivo. These findings suggest that IGF-1R activation is generally involved in resistance to HDAC inhibitors and that targeting IGF-1R is an effective strategy for overcoming resistance to HDAC inhibitors in NSCLC.

Anti-proliferative effects of evodiamine in human lung cancer cells

BACKGROUND

Evodiamine, a compound isolated from the Evodia rutaecarpa Bentham (Rutaceae), is known to have a potential anti-proliferative activity in human cancer cells. However, the growth inhibitory activity against lung cancer cells and the underlying molecular mechanisms have been poorly determined. The present study was designed to examine the anti-proliferative effect of evodiamine in A549 human lung cancer cells.

METHODS

A549 cells were treated with the compounds from Evodia rutaecarpa, and the anti-proliferative activity was evaluated by the sulforhodamine B assay. The mechanisms of action for the growth inhibitory activity of evodiamine on A549 human lung cancer cells were evaluated using flow cytometry for cell cycle distribution, and Western blot for assessment of accumulation and phosphorylation of potential target proteins.

RESULTS

Evodiamine exhibited a potent anti-proliferative activity against A549 human lung cancer cells. Flow cytometric analysis revealed that evodiamine induced cell cycle arrest at G2/M phase and apoptosis in the A549 cells. The cell cycle arrest was well correlated with the inhibition of cyclin B1, cyclin A, cdk2 and p-cdc2 (Tyr15) and increase of p-chk1 (Ser345) and p-chk2 (Thr68). Evodiamine also significantly increased the ratio of Bax/Bcl-2 and decreased procaspase-3, suggesting evodiamine-induced apoptosis via the intrinsic apoptotic pathway. In addition, evodiamine inhibited the expression of p-ERK and ERK.

CONCLUSIONS

These findings suggest that the anti-proliferative effect of evodiamine was associated in part with the induction of G2/M phase cell cycle arrest and apoptosis, and down-regulation of ERK in human lung cancer cells.

Abstract 1716: Targeting the insulin-like growth factor receptor/Insulin receptor and Src signaling network for the treatment of non-small cell lung cancer

Insulin-like growth factor I receptor (IGF-1R)-mediated signaling plays an important role in the proliferation, survival, and metastasis of cancer cells. The IGF-1R-targeting anticancer agents including monoclonal antibodies and small molecule tyrosine kinase inhibitors (TKIs) have been developed, but their antitumor effects have been marginal and limited in clinical trials. Therefore, the mechanism underlying resistance to the IGF-1R-targeting therapies and the rational combination strategies to overcome potential drug resistance need to be investigated. In this study, we demonstrated the association of Src with the resistance to the IGF-1R TKI in non-small cell lung cancer (NSCLC). We found the co-activation of IGF-1R/IR and Src in various human NSCLC cell lines, The mRNA expression and phosphorylation of IGF-1R and Src were also significantly correlated with each other in NSCLC databases from a public dataset and a tissue microarray (n=353). Next, we found Src can be activated through multiple pathways including EGFR and integrin β3 signaling and function as an alternative kinase for phosphorylation of IGF-1R, especially at Tyr1135/36, but not Tyr1131. Src is activated in lung cancer cells possessing both primary and acquired resistance to an IGF-1R TKI. Consistent with the results, inhibition of Src significantly attenuated activation of IGF-1R/IR and co-targeting of IGF-1R and Src effectively suppressed cell proliferation, colony formation, and tumor growth in vitro and in vivo. Taken together, these results suggest that Src causes resistance to IGF-1R TKIs by functioning as a key downstream modulator of multiple signaling pathways for IGF-1R phosphorylation and thus co-targeting IGF-1R and Src could be an effective therapeutic strategy for NSCLC.

Citation Format: Hye-Young Min, Hye Jeong Yun, Hyo-Jong Lee, Jaebeom Cho, Hyun-Ji Jang, Kyung Min Kim, Woo-Young Kim, Seung-Hyun Oh, Diane Liu, J. Jack Lee, Waun Ki Hong, Ignacio I. Wistuba, Ho-Young Lee. Targeting the insulin-like growth factor receptor/Insulin receptor and Src signaling network for the treatment of non-small cell lung cancer. [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 1716. doi:10.1158/1538-7445.AM2014-1716

One "8"-shaped scleral suture to treat rhegmatogenous retinal detachment: a refined procedure of minimal scleral buckling

The aim of this study was to investigate the outcomes of one "8"-shaped scleral suture of minimal scleral buckling (MSB) surgery without sub-retinal drainage for rhegmatogenous retinal detachment (RRD) treatment. Thirty patients (30 eyes) with RRD were recruited. Thirty eyes with RRD were repaired by one "8"-shaped scleral suture of minimal buckling without subretinal drainage by one surgeon. The refined MSB procedure is described. Reattachment time and best-corrected visual acuity (BCVA) were observed. The age of the 30 patients ranged from 17 to 65 years (mean, 43.1 ± 8.6 years). The retinas of 19 eyes (63.3%) reattached within 12 h of the operations, and those of 11 eyes (67%) reattached within 72 h. The average time of follow-up was 10.4 ± 2.8 months. BCVAs were increased in 27 eyes (90%), whereas those of 3 eyes did not change. The mean preoperative BCVA was 0.738 ± 0.368 log minimal angle of resolution (MAR), and mean postoperative BCVA was 0.422 ± 0.278 logMAR, and the difference was statistically significant (P < 0.05). The sponge for buckling in only one eye exposed from the conjunctiva was taken out, and the retina remained attached. In conclusion, an "8"-shaped scleral suture of MSB without sub-retinal drainage is an efficient procedure to treat selected RRD cases.

Transcriptional and posttranslational regulation of insulin-like growth factor binding protein-3 by Akt3

Insulin-like growth factor (IGF)-dependent and -independent antitumor activities of insulin-like growth factor binding protein-3 (IGFBP-3) have been proposed in human non-small cell lung cancer (NSCLC) cells. However, the mechanism underlying regulation of IGFBP-3 expression in NSCLC cells is not well understood. In this study, we show that activation of Akt, especially Akt3, plays a major role in the mRNA expression and protein stability of IGFBP-3 and thus antitumor activities of IGFBP-3 in NSCLC cells. When Akt was activated by genomic or pharmacologic approaches, IGFBP-3 transcription and protein stability were decreased. Conversely, suppression of Akt increased IGFBP-3 mRNA levels and protein stability in NSCLC cell lines. Characterization of the effects of constitutively active form of each Akt subtype (HA-Akt-DD) on IGFBP-3 expression in NSCLC cells and a xenograft model indicated that Akt3 plays a major role in the Akt-mediated regulation of IGFBP-3 expression and thus suppression of Akt effectively enhances the antitumor activities of IGFBP-3 in NSCLC cells with Akt3 overactivation. Collectively, these data suggest a novel function of Akt3 as a negative regulator of IGFBP-3, indicating the possible benefit of a combined inhibition of IGFBP-3 and Akt3 for the treatment of patients with NSCLC.

A preclinical murine model for the detection of circulating human tumor cells

BACKGROUND/AIM

Circulating tumor cells (CTCs), cancer cells that disseminate from primary tumors and enter the bloodstream in the course of metastasis, may serve as an important indicator of metastatic disease and poor prognosis in patients with cancer. The aim of this study was to establish a preclinical animal model for detecting and studying human CTCs.

MATERIALS AND METHODS

We performed a renal subcapsular implantation of human cancer cells in immunodeficient mice and recorded primary tumor growth, CTCs, and metastatic tumor development.

RESULTS

Immunofluorescence, or immunohistochemical staining and whole-body imaging analysis revealed that the implanted cells developed primary renal tumors, CTCs were detected, and successfully established metastatic tumors in several organs, including the lung, colon, and lymph nodes, depending on the implanted cells.

CONCLUSION

This model may be useful for detecting and characterizing CTCs and for investigating the mechanisms underlying the course of tumor metastasis.

Combating resistance to anti-IGFR antibody by targeting the integrin β3-Src pathway

BACKGROUND

Several phase II/III trials of anti-insulin-like growth factor 1 receptor (IGF-1R) monoclonal antibodies (mAbs) have shown limited efficacy. The mechanisms of resistance to IGF-1R mAb-based therapies and clinically applicable strategies for overcoming drug resistance are still undefined.

METHODS

IGF-1R mAb cixutumumab efficacy, alone or in combination with Src inhibitors, was evaluated in 10 human head and neck squamous cell carcinoma (HNSCC) and six non-small cell lung cancer (NSCLC) cell lines in vitro in two- or three-dimensional culture systems and in vivo in cell line- or patient-derived xenograft tumors in athymic nude mice (n = 6-9 per group). Cixutumumab-induced changes in cell signaling and IGF-1 binding to integrin β3 were determined by Western or ligand blotting, immunoprecipitation, immunofluorescence, and cell adhesion analyses and enzyme-linked immunosorbent assay. Data were analyzed by the two-sided Student t test or one-way analysis of variance.

RESULTS

Integrin β3-Src signaling cascade was activated by IGF-1 in HNSCC and NSCLC cells, when IGF-1 binding to IGF-1R was hampered by cixutumumab, resulting in Akt activation and cixutumumab resistance. Targeting integrin β3 or Src enhanced antitumor activity of cixutumumab in multiple cixutumumab-resistant cell lines and patient-derived tumors in vitro and in vivo. Mean tumor volume of mice cotreated with cixutumumab and integrin β3 siRNA was 133.7 mm(3) (95% confidence interval [CI] = 57.6 to 209.8 mm(3)) compared with those treated with cixutumumab (1472.5 mm(3); 95% CI = 1150.7 to 1794.3 mm(3); P < .001) or integrin β3 siRNA (903.2 mm(3); 95% CI = 636.1 to 1170.3 mm(3); P < .001) alone.

CONCLUSIONS

Increased Src activation through integrin ανβ3 confers considerable resistance against anti-IGF-1R mAb-based therapies in HNSCC and NSCLC cells. Dual targeting of the IGF-1R pathway and collateral integrin β3-Src signaling module may override this resistance.

Abstract 5265: Akt regulates insulin-like growth factor binding protein-3 by modulating its expression in human non-small cell lung cancer cells

Since it has been suggested the insulin-like growth factor (IGF)-independent antitumor effect of insulin-like growth factor binding protein-3 (IGFBP-3) in human cancer cells, the mechanism underlying the regulation of IGFBP-3 in the cells has not been fully studied. Therefore, in this study, we investigated the precise role of Akt in the regulation of cellular IGFBP-3 in human lung cancer cells. Inhibition of PI3K/Akt by siRNA transfection targeting Akt or by treatment with an inhibitor (LY294002) enhanced antiproliferative and proapoptotic effects of IGFBP-3 in lung cancer cells. Additional pharmacological (by using a small molecule inhibitor) or genomic (by siRNA-based silencing of PTEN or overexpression of dominant-negative Akt) approaches suggest that Akt regulates the expression and stability of IGFBP-3 protein. Further characterization of the role of Akt in the regulation of IGFBP-3 by introduction of constitutively active form of each Akt subtype indicates that Akt3 destabilized cellular IGFBP-3 and suppressed retinoic acid-induced IGFBP-3 expression in both TSC2-/- MEF and H226B lung cancer cells. Collectively, these data suggest a novel function of Akt, especially Akt3, as a negative regulator of IGFBP-3 and, further, the possible implication of combined treatment targeting IGFBP-3 and Akt in the treatment of lung cancer.

Citation Format: Quanri Jin, Hye-Young Min, Young Mi Whang, Yeul Hong Kim, Ho-Young Lee. Akt regulates insulin-like growth factor binding protein-3 by modulating its expression in human non-small cell lung cancer cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5265. doi:10.1158/1538-7445.AM2013-5265