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Arachidonic and adrenic acids in the membrane play key roles in ferroptosis, but how these fatty acids are manipulated in cells is largely unknown. Here, we reveal that lipoprotein-associated phospholipase A2 (Lp-PLA2) controls intracellular phospholipid metabolism and contributes to ferroptosis resistance. A metabolic drug screen identified that darapladib (SB-480848), an inhibitor of Lp-PLA2, synergistically induced ferroptosis with GPX4 inhibitors. Notably, darapladib was able to enhance ferroptosis under lipoprotein-deficient or serum-free conditions. Furthermore, Lp-PLA2 was located in the membrane and cytoplasm and suppressed ferroptosis, suggesting the critical role of intracellular Lp-PLA2. Lipidomic analysis showed that phosphatidylethanolamine (PE) species were generally enriched, while lysophosphatidylethanolamine (lysoPE) and free fatty acid levels were reduced, upon darapladib treatment. Finally, combination treatment with darapladib and PACMA31, a GPX4 inhibitor, efficiently inhibited tumor growth in a xenograft model. Our study suggests that inhibition of Lp-PLA2 is a potential therapeutic strategy to enhance ferroptosis in cancer treatment.

Supplementary Figure 3. Silencing of HIF-1α restores sensitivity of immune-resistant human cancer cells to lysis by tumor-specific human CTLs.

Cancer immunoediting drives the adaptation of tumor cells to host immune surveillance. Immunoediting driven by antigen (Ag)-specific T cells enriches NANOG expression in tumor cells, resulting in a stem-like phenotype and immune resistance. Here, we identify HDAC1 as a key mediator of the NANOG-associated phenotype. NANOG upregulated HDAC1 through promoter occupancy, thereby decreasing histone H3 acetylation on K14 and K27. NANOG-dependent, HDAC1-driven epigenetic silencing of cell-cycle inhibitors CDKN2D and CDKN1B induced stem-like features. Silencing of TRIM17 and NOXA induced immune and drug resistance in tumor cells by increasing antiapoptotic MCL1. Importantly, HDAC inhibition synergized with Ag-specific adoptive T-cell therapy to control immune refractory cancers. Our results reveal that NANOG influences the epigenetic state of tumor cells via HDAC1, and they encourage a rational application of epigenetic modulators and immunotherapy in treatment of NANOG+ refractory cancer types. Cancer Res; 77(18); 5039–53. ©2017 AACR.

Supplementary Figure 2. Immune selection induces HIF-1α in CaSki human cancer cell.

Supplementary Figure 1. SCP3 overexpression induces NANOG-mediated immune resistance and stem-like properties in human cancer cells. Supplementary Figure 2. MHC class I expression and CTL activation capacity of tumor cells are unaffected by SCP3 expression. Supplementary Figure 3. SCP3 expression in tumor cells does not control the viability of CTLs. Supplementary Figure 4. The SCP3 axis is conserved across various human cancer types. Supplementary Figure 5. CDK4/6 inhibitor is more effective than other drugs in SCP3-positive tumor cells. Supplementary Figure 6. Schematic interpretation of therapeutic resistance and tumorigenicity through the SCP3 axis.

Supplementary Figure 1. VEGFA mRNA is up-regulated in human cancer cells subjected to immune selection.

Supplementary Figure 1. Immune-edited CaSki P3 cells showed a stem-like phenotype. Supplementary Figure 2. NANOG does not effect on acetylation of histone H4. Supplementary Figure 3. Expression of HDAC genes, and genes involved in negative regulators of MCL-1 protein by NANOG-HDAC1 axis. Supplementary Figure 4. The NANOG-HDAC1 axis controls immune-resistance, drug-resistance and stem-like property in multiple types of human cancer cells. Supplementary Figure 5. Generation of MDA-MB231 P3 immune-resistant cell lines. Supplementary Figure 6. Regulation of HAT genes by NANOG-HDAC1 axis. Supplementary Figure 7. Schematic interpretation of immune selection-mediated epigenetic change and implications of epigenetic therapy.

Cell lines, Western blot (WB) analysis, Luciferase assay, Trypan blue exclusion assay, Immunohistochemistry, ChIP and quantitative ChIP (qChIP) assays, SUPPLEMENTARY REFERENCES.

Purpose: Adaptation to host immune surveillance is now recognized as a hallmark of cancer onset and progression, and represents an early, indispensable event in cancer evolution. This process of evolution is first instigated by an immune selection pressure imposed by natural host surveillance mechanisms and may then be propagated by vaccination or other types of immunotherapy.Experimental Design: We developed a system to simulate cancer evolution in a live host and to dissect the mechanisms responsible for adaptation to immune selection. Here, we show that the oxygen-sensitive α subunit of hypoxia-inducible factor 1 (HIF-1α) plays a central role in cancer immune adaptation under conditions of normal oxygen tension.Results: We found that tumor cells gain HIF-1α in the course of immune selection under normoxia and that HIF-1α renders tumor cells resistant to lysis by tumor-specific cytotoxic T lymphocytes (CTL) in culture and in mice. The effects of HIF-1α on immune adaptation were mediated through VEGFA-dependent activation of the AKT and ERK signaling pathways, which induced an antiapoptotic gene expression network in tumor cells.Conclusions: Our study therefore establishes a link between immune selection, overexpression of HIF-1α, and cancer immune adaptation under normoxia, providing new opportunities for molecular intervention in patients with cancer. Clin Cancer Res; 21(6); 1438–46. ©2015 AACR.

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PDF file - 1008KB, mRNA and protein expression of Api5 in TC-1/P0 and TC-1/P3 A17 cells (S1). Api5 expression in murine tumors and their immune resistance (S2). In vitro Generation and Characterization of KKM MART1-specific CTL clone (S3). Characterization of antigen presenting capacity of A375/no insert and A375/API5 cells in vitro (S4). API5 activates FGFR1 signaling pathway (S5).

4-O-methylascochlorin (MAC) is a 4-fourth carbon-substituted derivative of ascochlorin, a compound extracted from a phytopathogenic fungus Ascochyta viciae. MAC induces apoptosis and autophagy in various cancer cells, but the effects of MAC on apoptosis and autophagy in cervical cancer cells, as well as how the interaction between apoptosis and autophagy mediates the cellular anticancer effects are not known. Here, we investigated that MAC induced apoptotic cell death of cervical cancer cells without regulating the cell cycle and promoted autophagy by inhibiting the phosphorylation of serine-threonine kinase B (Akt), mammalian target of rapamycin (mTOR), and 70-kDa ribosomal protein S6 kinase (p70S6K). Additional investigations suggested that Bcl-2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP-3), but not Hypoxia-inducible factor 1 alpha (HIF-1α), is a key regulator of MAC-induced apoptosis and autophagy. BNIP-3 siRNA suppressed MAC-induced increases in cleaved- poly (ADP-ribose) polymerase (PARP) and LC3II expression. The pan-caspase inhibitor Z-VAD-FMK suppressed MAC-induced cell death and enhanced MAC-induced autophagy. The autophagy inhibitor chloroquine (CQ) enhanced MAC-mediated cell death by increasing BNIP-3 expression. These results indicate that MAC induces apoptosis to promote cell death and stimulates autophagy to promote cell survival by increasing BNIP-3 expression. This study also showed that co-treatment of cells with MAC and CQ further enhanced the death of cervical cancer cells.

Immune selection drives tumor cells to acquire refractory phenotypes. We previously demonstrated that cytotoxic T lymphocyte (CTL)-mediated immune pressure enriches NANOG(+) tumor cells with stem-like and immune-refractory properties that make them resistant to CTLs. Here, we report that the emergence of refractory phenotypes is highly associated with an aberrant macroautophagic/autophagic state of the NANOG(+) tumor cells and that the autophagic phenotype arises through transcriptional induction of MAP1LC3B/LC3B by NANOG. Furthermore, we found that upregulation of LC3B expression contributes to an increase in EGF secretion. The subsequent hyperactivation of EGFR-AKT signaling rendered NANOG(+) tumor cells resistant to CTL killing. The NANOG-LC3B-p-EGFR axis was preserved across various types of human cancer and correlated negatively with the overall survival of cervical cancer patients. Inhibition of LC3B in immune-refractory tumor models rendered tumors susceptible to adoptive T-cell transfer, as well as PDCD1/PD-1 blockade, and led to successful, long-term control of the disease. Thus, our findings demonstrate a novel link among immune-resistance, stem-like phenotypes, and LC3B-mediated autophagic secretion in immune-refractory tumor cells, and implicate the LC3B-p-EGFR axis as a central molecular target for controlling NANOG(+) immune-refractory cancer. Abbreviations: ACTB: actin beta; ATG7: autophagy related 7; BafA1: bafilomycin A(1); CASP3: caspase 3; CFSE: carboxyfluorescein succinimidyl ester; ChIP: chromatin immunoprecipitation; CI: confidence interval; CIN: cervical intraepithelial neoplasia; CSC: cancer stem cell; CTL: cytotoxic T lymphocyte; EGF: epidermal growth factor; EGFR: epidermal growth factor receptor; FIGO: International Federation of Gynecology and Obstetrics; GFP: green fluorescent protein; GZMB: granzyme B; HG-CIN: high-grade CIN; IHC: immunohistochemistry; LG-CIN: low-grade CIN; LN: lymph node; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MCL1: myeloid cell leukemia sequence 1; MLANA/MART-1: melanoma antigen recognized by T cells 1; MUT: mutant; NANOG: Nanog homeobox; PDCD1/PD-1: programmed cell death 1; PMEL/gp100: premelanosome protein; RTK: receptor tyrosine kinase; TMA: tissue microarray; WT: wild type

In this study, polyphenylene sulfide (PPS) was introduced in polyphenylene ether (PPE) blend to improve the processability of PPE and to secure the flame retardancy of the blend without deteriorating physical properties. Through the study of the binary blend of PPE/PPS, it was found that the shear thinning behavior and the external lubrication effect of PPS can improve the processability of PPE. Thermal analysis of the blend showed that the glass transition temperature of the PPS component decreases by the plasticization while that of the PPE component increases by the anti-plasticization effect. The modulus of the binary blend increased with the PPS content, and the tensile strength decreased but followed the additive rule. The change in tensile properties can be explained by the synergy effect of partial miscibility between PPE and PPS due to structural similarity, and non-isotropic morphology formation. Impact strength increased sharply in PPE60 due to the mechanical grafting effect by co-continuous phase formation. In the ternary blend with SEBS-MAH applied to PPE60, the impact strength steep increased at a content of 10 wt% or more due to the dramatic morphology change based on the compatibilization effect. Flame retardancy of V0 was also observed in all compositions where SEBS-MAH was applied within 20 phr.

"Foreignization" of tumor cells via delivery of a non-self foreign antigen (Ag) into tumors is an appealing strategy to initiate anti-tumor immunity that can facilitate tumor rejection by pre-existing foreign-Ag-reactive T cells. However, the immune-suppressive factors in the tumor microenvironment (TME) limit the durable and potent immune response of these cells against tumor antigens, stressing the need for improved tumor-foreignization strategies. Here, we demonstrate that blockade of programmed cell death ligand 1 (PD-L1) on both tumor cells and dendritic cells (DCs) can markedly potentiate the induction of tumor-reactive T cells, thereby strengthening the anti-tumor immunity ignited by tumor-foreignization. Specifically, we developed a polymeric nanoconjugate (PEG-HA-OVA/PPLs), consisting of siPD-L1-based polyplexes, PEGylated hyaluronic acid as the CD44-targeting moiety, and ovalbumin (OVA) as a model foreign antigen. Notably, PEG-HA-OVA/PPLs were simultaneously delivered into CD44

Synaptonemal complex protein 3 (SCP3), a member of the Cor1 family, has been implicated in cancer progression, and therapeutic resistance, as well as cancer stem cell (CSC)-like properties. Previously, we demonstrated that SCP3 promotes these aggressive phenotypes via hyperactivation of the AKT signaling pathway, however, the underlying mechanisms responsible for SCP3-induced AKT activation remain to be elucidated. In this study, we demonstrated that the EGF-EGFR axis is the primary route through which SCP3 acts to activate AKT signaling. SCP3 triggers the EGFR-AKT pathway through transcriptional activation of EGF. Notably, neutralization of secreted EGF by its specific monoclonal antibody reversed SCP3-mediated aggressive phenotypes with a concomitant reversal of EGFR-AKT activation. In an effort to elucidate the molecular mechanisms underlying SCP3-induced transcriptional activation of EGF, we identified Jun activation domain-binding protein 1 (JAB1) as a binding partner of SCP3 using a yeast two-hybrid (Y2H) assay system, and we demonstrated that SCP3 induces EGF transcription through physical interaction with JAB1. Thus, our findings establish a firm molecular link among SCP3, EGFR, and AKT by identifying the novel roles of SCP3 in transcriptional regulation. We believe that these findings hold important implications for controlling SCP3high therapeutic-refractory cancer.

4-O-Methyl-ascochlorin (MAC), a derivative of the prenyl-phenol antibiotic ascochlorin, promotes accumulation of HIF-1α. In this study, we investigated the molecular mechanisms of the effect of MAC on cell migration and mesenchymal epithelial transition (EMT) processes in breast cancer cells. MAC upregulated cell motility and migration regardless of cell viability, and promoted EMT features by regulating EMT-related proteins and transcription. In addition, the MAC-induced increase in the EMT was closely related to activation of HIF-1α expression. However, the MAC-induced EMT was not associated with AMPK phosphorylation or intracellular ROS, which stimulate HIF-1α expression. Similarly, HIF-1α-mediated autophagy induced by MAC was not related to EMT-related proteins. Inhibition of HIF-1α activity inhibited MAC-stimulated cell migration and increased MAC-induced cell death, indicating that HIF-1α activation is important for MAC-mediated cell migration and survival in breast cancer cells. Together, these results suggest that MAC can be used to investigate the link between HIF-1α activation and other oncogenes or tumor suppressors in breast cancer cells.

Immune checkpoint blockade (ICB) therapy has shifted the paradigm for cancer treatment. However, the majority of patients lack effective responses because of the emergence of immune-refractory tumors that disrupt the amplification of antitumor immunity. Therefore, the identification of clinically available targets that restrict antitumor immunity is required to develop potential combination therapies. Here, using transcriptomic data on patients with cancer treated with programmed cell death protein 1 (PD-1) therapy and newly established mouse preclinical anti-PD-1 therapy-refractory models, we identified NANOG as a factor restricting the amplification of the antitumor immunity cycle, thereby contributing to the immune-refractory feature of the tumor microenvironment (TME). Mechanistically, NANOG induced insufficient T cell infiltration and resistance to CTL-mediated killing via the histone deacetylase 1-dependent (HDAC1-dependent) regulation of CXCL10 and MCL1, respectively. Importantly, HDAC1 inhibition using an actionable agent sensitized NANOGhi immune-refractory tumors to PD-1 blockade by reinvigorating the antitumor immunity cycle. Thus, our findings implicate the NANOG/HDAC1 axis as a central molecular target for controlling immune-refractory tumors and provide a rationale for combining HDAC inhibitors to reverse the refractoriness of tumors to ICB therapy.

The authors have requested that this preprint be removed from Research Square.

Immunotherapy has emerged as a powerful approach to cancer treatment. However, immunotherapeutic resistance limits its clinical application. Therefore, identifying immune-resistant factors, which can be targeted by clinically available drugs and it also can be a companion diagnostic marker, is needed to develop combination strategies. Here, using the transcriptome data of patients, and immune-refractory tumor models, we identify TCTP as an immune-resistance factor that correlates with clinical outcome of anti-PD-L1 therapy and confers immune-refractory phenotypes, decreased T cell trafficking to the tumor and resistance to cytotoxic T lymphocyte-mediated tumor cell killing. Mechanistically, TCTP activates the EGFR-AKT-MCL-1/CXCL10 pathway by phosphorylation-dependent interaction with Na, K ATPase. Furthermore, treatment with dihydroartenimsinin, the most effective agent impending the TCTP-mediated-refractoriness, synergizes with T cell-mediated therapy to control immune-refractory tumors. Thus, our findings suggest a role of TCTP in promoting immune-refractoriness, thereby encouraging a rationale for combination therapies to enhance the efficacy of T cell-mediated therapy.

N-glycolylneuraminic acid (NeuGc), a non-human sialic acid derivative synthesized by cytidine-5&prime, monophospho-N-acetylneuraminic acid hydroxylase (CMAH), plays a crucial role in mediating infections by certain pathogens. Although it has been postulated that NeuGc biosynthesis and CMAH expression are downregulated during microbial infection, the underlying mechanisms remain unclear. The present study showed that exposure to lipopolysaccharide (LPS), a Gram-negative bacterial endotoxin, leads to loss of NeuGc biosynthesis in pig small intestinal I2I-2I cells. This LPS-induced NeuGc loss was accompanied by decreased CMAH transcript levels, especially intestine-specific 5&prime, pcmah-1. Furthermore, LPS suppressed the activity of the Pi promoter responsible for 5&prime, pcmah-1 by inhibiting DNA binding of Est1. These findings provide insight into the regulatory mechanisms of Neu5Gc biosynthesis during pathogenic infectious events, which may represent a host defense mechanism that protects the self against pathogenic bacterial infections even in non-sanitary environments.

The cell-free approach to foreignizing tumor cells with non-self antigens has received increasing attention as a method to induce cytotoxic T lymphocyte (CTL)-mediated immunological rejection of tumors, because the clinical translation of the conventional CTL-based cancer immunotherapies has been limited by a complicated manufacturing process and autotransplantation. In this study, we prepared matrix metalloproteinase 9 (MMP9)-responsive polymeric conjugates consisting of PEGylated hyaluronic acid (HA) as the targeting moiety and ovalbumin (OVA) as the model foreign antigen. The MMP9-cleavable linker was introduced between PEG and the HA backbone to facilitate the detachment of the PEG corona from the conjugate at the tumor site. From the in vitro cellular uptake study, it was revealed that the conjugate was effectively taken up by the CD44-expressing TC-1 cancer cells in the presence of MMP9 via receptor-mediated endocytosis. When the conjugate was systemically administered into the tumor-bearing mice with endogenous OVA-specific CTLs, the tumor growth was markedly inhibited, which was attributed to the significant antigen presentation on the tumor cells. Overall, the MMP9-responsive conjugates bearing foreign antigens might have the potential as an alternative to CTL-based cancer immunotherapeutics.

Meteorin‐like (metrnl) is a recently identified adipomyokine that beneficially affects glucose metabolism; however, its underlying mechanism of action is not completely understood. We here show that the level of metrnl increases in vitro under electrical pulse stimulation and in vivo in exercised mice, suggesting that metrnl is secreted during muscle contractions. In addition, metrnl increases glucose uptake via the calcium‐dependent AMPKα2 pathway in skeletal muscle cells and increases the phosphorylation of HDAC5, a transcriptional repressor of GLUT4, in an AMPKα2‐dependent manner. Phosphorylated HDAC5 interacts with 14‐3‐3 proteins and sequesters them in the cytoplasm, resulting in the activation of GLUT4 transcription. An intraperitoneal injection of recombinant metrnl improved glucose tolerance in mice with high‐fat‐diet‐induced obesity or type 2 diabetes, but not in AMPK β1β2 muscle‐specific null mice. Metrnl improves glucose metabolism via AMPKα2 and is a promising therapeutic candidate for glucose‐related diseases such as type 2 diabetes., We found that metrnl, known as an adipomyokine, is secreted during muscle contractions. Metrnl increases glucose uptake via AMPKα in skeletal muscle cells and increases the phosphorylation of HDAC5 and TBC1D1 in AMPKα‐dependent manner. Recombinant metrnl improves glucose tolerance in mice with obesity or type 2 diabetes. These results suggest that metrnl is a promising therapeutic candidate for diabetes.

Cancer immunotherapy, in the form of vaccination, adoptive cellular transfer, or immune checkpoint inhibitors, has emerged as a promising practice within the field of oncology. However, despite the developing field's potential to revolutionize cancer treatment, the presence of immunotherapeutic-resistant tumor cells in many patients present a challenge and limitation to these immunotherapies. These cells not only indicate immunotherapeutic resistance, but also show multi-modal resistance to conventional therapies, abnormal metabolism, stemness, and metastasis. How can immunotherapeutic-resistant tumor cells render multi-malignant phenotypes? We reasoned that the immune-refractory phenotype could be associated with multi-malignant phenotypes and that these phenotypes are linked together by a factor that acts as the master regulator. In this review, we discussed the role of the embryonic transcription factor NANOG as a crucial master regulator we named “common factor” in multi-malignant phenotypes and presented strategies to overcome multi-malignancy in immunotherapeutic-resistant cancer by restraining the NANOG-mediated multi-malignant signaling axis. Strategies that blunt the NANOG axis could improve the clinical management of therapy-refractory cancer.

In the present study, we isolated pCMAH house-keeping promoter regions (Ph), which are responsible for transcriptional regulation and which are located upstream of the alternative transcript pcmah-2. Luciferase reporter assays using serial construction of each deleted promoter demonstrated that the Ph promoter was highly active in pig-derived kidney PK15. Ph promoter of pcmah lacked a TATA box, but contained three putative Sp1 binding sites. Mutations of these Sp1 binding sites always resulted in the reduction of luciferase activities in Ph-334. In addition, treatment with mithramycin A (25-100 nM) decreased the luciferase activities of the Ph promoters and NeuGc expression in a dose-dependent manner. Electrophoretic mobility shift assay analysis revealed that the probes containing each Sp1 binding site bound to Sp1. Taken together, the results indicate that Sp1 bind to their putative binding sites on the Ph promoter regions of pcmah and positively regulate the promoter activity in pig kidney cells. Interspecies comparison of 5'UTRs and 5'flanking regions shows high homology between pig and cattle, and Sp1 binding sites existing in genomic regions corresponding Ph region are evolutionally conserved.

Background: PPIB (Peptidylprolyl isomerase B) is involved in cellular transcriptional regulation, immune response, chemotaxis, and proliferation. Recent studies have shown that PPIB is linked to tumor progression and chemoresistance. The role of PPIB in non-small cell lung cancer (NSCLC) has not been explored. We aimed to investigate the significance of PPIB in NSCLC and its mechanism of action. Methods: The role of PPIB was assessed in 5 human NSCLC cell lines. PPIB expression was examined using RNA in situ hybridization (RNA-ISH) on tissue microarrays consisting of 544 NSCLC cases and Ki-67 expression was evaluated by immunohistochemical assays (IHC). RNA-ISH and IHC scores were evaluated by digital image analysis and used to compare patients' prognostic outcomes. Results: PPIB overexpression promoted proliferation, colony formation and migration of NSCLC tumor cells. We also confirmed the oncogenic properties of PPIB expression in PPIB transfected human bronchogenic epithelial cells. In NSCLC tumor samples, high PPIB expression correlated with lymph node metastasis and recurrence (p = 0.018 and 0.026, respectively), while Ki-67 overexpression correlated with advanced tumor stage (p < 0.001). Patients with high PPIB expression assessed by RNA-ISH (PPIBhigh), exhibited significantly shorter disease-free survival (DFS) time than those who were PPIBlow [HR (95% CI) = 1.53 (1.11-2.10), p = 0.008]. Multivariate analysis revealed that combined Ki-67high/PPIBhigh expression was an independent predictor of shorter DFS [HR (95% CI) = 1.71 (1.26-2.31), p < 0.001]. Conclusions: These findings suggest that PPIB plays a role in NSCLC tumor growth and is associated with unfavorable disease-free survival. PPIB may have value as a prognostic marker and a potential target molecule for NSCLC treatment. Citation Format: Jeongwon Kim, Joon-Yong Chung, Stephen M. Hewitt, Ilseon Hwang, Joon Seon Song, Chang-Min Choi, Eunho Cho, Kwon-Ho Song, Tae Woo Kim, Kris Ylaya. PPIB expression associates with tumor progression and unfavorable disease-free survival of non-small cell lung cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4311.

T cell-based immunotherapy has shifted the paradigm for cancer treatment. However, the majority of patients lack effective responses due to presence of immune-refractory tumor cells that limits its clinical success by blocking amplification of anti-tumor immunity cycle. Previously, we found that immune selection by T-cell based immunotherapy drives the evolution of tumors toward immunotherapeutic refractoriness including multimodal resistant and stem-like phenotype via activation of NANOG-TCL1A-AKT axis. Here, we report a crucial role of HSP90A at the crossroads between NANOG-TCL1A axis and the refractoriness of immune-edited tumor cells by identifying HSP90AA1 as a novel NANOG transcriptional target. Furthermore, we found that TCL1A is a novel client of HSP90A, and demonstrated that HSP90A potentiates AKT activation through TCL1A stabilization and thereby contributes to refractoriness in NANOGhigh immune-edited tumor cells. Importantly, inhibition of HSP90A sensitizes immune-refractory tumor cells to T cell-based immunotherapy and elicits effective anti-tumor response by re-invigorating anti-tumor immune cycle of tumor-reactive T cells. Our findings implicate that the NANOG-HSP90A pathway is a central molecular axis and a potential target for immune-refractory tumor. Citation Format: Se Jin Oh, Tae Woo Kim, Kwon-Ho Song, Suyeon Kim. NANOG-HSP90A axis confers immunotherapeutic resistance by blocking anti-tumor immunity cycle [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1033.

Meteorin-like (metrnl) is a recently identified adipomyokine that has beneficial effects on glucose metabolism. However, its underlying mechanism of action is not completely understood. In this study, we have shown that a level of metrnl increase in vitro under electrical-pulse-stimulation (EPS) and in vivo in exercise mice, suggesting that metrnl is an exercise-induced myokine. In addition, metrnl increases glucose uptake through the calcium-dependent AMPK pathway. Metrnl also increases the phosphorylation of HDAC5, a transcriptional repressor of GLUT4, in an AMPK-dependent manner. Phosphorylated HDAC5 interacts with 14-3-3 proteins and sequesters them in the cytoplasm, resulting in the activation of GLUT4 transcription. The intraperitoneal injection of recombinant metrnl improves glucose tolerance in mice with high fat-induced obesity or type 2 diabetes (db/db), but this is not seen in AMPK β1β2 muscle-specific null mice (AMPK β1β2 MKO). In conclusion, we have demonstrated that metrnl induces beneficial effects on glucose metabolism via AMPK and is a promising therapeutic candidate for glucose-related diseases such as type 2 diabetes.

Cancer immunoediting enriches NANOG expression in tumor cells, resulting in multi-drug resistance and stem-like phenotypes. We previously demonstrated that these NANOG-associated phenotypes are promoted through HDAC1 transcriptional upregulation. In this study, we identified that NANOG also contributes to the stabilization of HDAC1 protein through the AKT signaling pathway. NANOG-AKT axis leads to phosphor-dependent inactivation of CHFR, an E3 ligase for HDAC1 protein, and thereby inhibiting the ubiquitin-mediated degradation of HDAC1. Furthermore, AKT inhibition disrupts HDAC1 WT-mediated phenotypes but had no effect on the phenotypes mediated by HDAC1 FM, a mutant that is unable to interact with CHFR. Critically, we applied a catalytic dead mutant, HDAC1-H141A, to uncover that HDAC1 confers immune-resistance, drug-resistance and stem-like phenotype in tumor cells through its catalytic activity. Collectively, our results establish a firm molecular link in immune-edited tumor cells among NANOG, AKT, CHFR, and HDAC1, identifying HDAC1 as a molecular target in controlling NANOGHIGH immune-refractory cancer.

The fusion between anaplastic lymphoma kinase (ALK) and echinoderm microtubule-associated protein-like 4 (EML4) is a causative factor in a unique subset of patients with non-small cell lung carcinoma (NSCLC). Although the inhibitor crizotinib, as it blocks the kinase activity of the resulting EML4-ALK fusion protein, displays remarkable initial responses, a fraction of NSCLC cases eventually become resistant to crizotinib by acquiring mutations in the ALK domain or activating bypass pathways via EGFR, KIT, or KRAS. Cancer stem cell (CSC) theory provides a plausible explanation for acquisition of tumorigenesis and resistance. However, the question as to whether EML4-ALK-driven tumorigenesis is linked with the stem-like property and whether the stemness is an effective target in controlling EML4-ALK+ NSCLC including crizotinib-resistant NSCLC cells has not been addressed. Here, we report that stem-like properties stem from ALK activity in EML4-ALK+ NSCLC cells. Notably, treatment with rapamycin, a CSC targeting agent, attenuates stem-like phenotypes of the EML4-ALK+ cells, which increased capability of tumor formation and higher expression of stemness-associated molecules such as ALDH, NANOG, and OCT4. Importantly, combinational treatment with rapamycin and crizotinib leads to synergistic anti-tumor effects on EML4-ALK+ NSCLC cells as well as on those resistant to crizotinib. Thus, we provide a proof of principle that targeting stemness would be a novel strategy to control intractable EML4-ALK+ NSCLC.

Metastatic recurrence after cancer treatments with radiation, cancer drugs, or even immunotherapeutic agents (cytokine, antibody, lymphocyte etc.) is often intractable and fatal for cancer patients. Therefore, molecular understanding of metastatic recurrence is necessary. Recently, these recurrent and metastatic tumor cells with resistance to cancer drugs have been reported to possess stem-like attributes and epithelial-mesenchymal transition (EMT) phenotype. Previously, we also found that antigen-specific cytotoxic T lymphocyte (CTL)-mediated immunotherapy conferred tumor cells with immune-resistant and stem-like phenotypes by hyper-activating NANOG/TCL1/AKT signaling axis. In this study, we report that these immunoedited cells have high metastatic capability and phenotypes. These cells exhibit enhanced migration, infiltration, and invasiveness in vitro as well as formation of metastatic lung nodules in vivo. Moreover, they display EMT-like features characterized by increased expression of BMI1 and TWIST1. Importantly, these pleiotropic phenotypes of metastasis through the expression of the EMT-associated molecules were critically dependent on the NANOG/TCL1A/AKT signaling axis, which was also conserved across multiple types of human cancer. Thus, we provide proof of the principle that inhibition of the NANOG axis is an effective strategy to control metastasis of immunoedited cancer, particularly, after CTL-based immunotherapy.

Purpose: Adaptation to host immune surveillance is now recognized as a hallmark of cancer onset and progression, and represents an early, indispensable event in cancer evolution. This process of evolution is first instigated by an immune selection pressure imposed by natural host surveillance mechanisms and may then be propagated by vaccination or other types of immunotherapy. Experimental Design: We developed a system to simulate cancer evolution in a live host and to dissect the mechanisms responsible for adaptation to immune selection. Here, we show that the oxygen-sensitive α subunit of hypoxia-inducible factor 1 (HIF-1α) plays a central role in cancer immune adaptation under conditions of normal oxygen tension. Results: We found that tumor cells gain HIF-1α in the course of immune selection under normoxia and that HIF-1α renders tumor cells resistant to lysis by tumor-specific cytotoxic T lymphocytes (CTL) in culture and in mice. The effects of HIF-1α on immune adaptation were mediated through VEGFA-dependent activation of the AKT and ERK signaling pathways, which induced an antiapoptotic gene expression network in tumor cells. Conclusions: Our study therefore establishes a link between immune selection, overexpression of HIF-1α, and cancer immune adaptation under normoxia, providing new opportunities for molecular intervention in patients with cancer. Clin Cancer Res; 21(6); 1438–46. ©2015 AACR.

Apoptosis inhibitor 5 (API5) has recently been identified as a tumor metastasis-regulating gene in cervical cancer cells. However, the precise mechanism of action for API5 is poorly understood. Here, we show that API5 increases the metastatic capacity of cervical cancer cells in vitro and in vivo via up-regulation of MMP-9. Interestingly, API5-mediated metastasis was strongly dependent on the Erk signaling pathway. Conversely, knock-down of API5 via siRNA technology decreased the level of phospho-Erk, the activity of the MMPs, in vitro invasion, and in vivo pulmonary metastasis. Moreover, the Erk-mediated metastatic action was abolished by the mutation of leucine into arginine within the heptad leucine repeat region, which affects protein-protein interactions. Thus, API5 increases the metastatic capacity of tumor cells by up-regulating MMP levels via activation of the Erk signaling pathway. [BMB Reports 2015; 48(6): 330-335]

The host immune system plays a pivotal role in the emergence of tumor cells that are refractory to multiple clinical interventions including immunotherapy, chemotherapy, and radiotherapy. Here, we examined the molecular mechanisms by which the immune system triggers cross-resistance to these interventions. By examining the biological changes in murine and tumor cells subjected to sequential rounds of in vitro or in vivo immune selection via cognate cytotoxic T lymphocytes, we found that multimodality resistance arises through a core metabolic reprogramming pathway instigated by epigenetic loss of the ATP synthase subunit ATP5H, which leads to ROS accumulation and HIF-1α stabilization under normoxia. Furthermore, this pathway confers to tumor cells a stem-like and invasive phenotype. In vivo delivery of antioxidants reverses these phenotypic changes and resensitizes tumor cells to therapy. ATP5H loss in the tumor is strongly linked to failure of therapy, disease progression, and poor survival in patients with cancer. Collectively, our results reveal a mechanism underlying immune-driven multimodality resistance to cancer therapy and demonstrate that rational targeting of mitochondrial metabolic reprogramming in tumor cells may overcome this resistance. We believe these results hold important implications for the clinical management of cancer.

Immunoediting caused by antitumor immunity drives tumor cells to acquire refractory phenotypes. We demonstrated previously that tumor antigen–specific T cells edit these cells such that they become resistant to CTL killing and enrich NANOGhigh cancer stem cell-like cells. In this study, we show that synaptonemal complex protein 3 (SCP3), a member of the Cor1 family, is overexpressed in immunoedited cells and upregulates NANOG by hyperactivating the cyclin D1–CDK4/6 axis. The SCP3–cyclin D1–CDK4/6 axis was preserved across various types of human cancer and correlated negatively with progression-free survival of cervical cancer patients. Targeting CDK4/6 with the inhibitor palbociclib reversed multiaggressive phenotypes of SCP3high immunoedited tumor cells and led to long-term control of the disease. Collectively, our findings establish a firm molecular link of multiaggressiveness among SCP3, NANOG, cyclin D1, and CDK4/6 and identify CDK4/6 inhibitors as actionable drugs for controlling SCP3high immune-refractory cancer. Significance: These findings reveal cyclin D1-CDK4/6 inhibition as an effective strategy for controlling SCP3high immune-refractroy cancer. Cancer Res; 78(10); 2638–53. ©2018 AACR.

The human chronic myelogenous cell line K562 has been used extensively as a model for the study of leukemia differentiation. We show here that treatment of K562 cells with caffeic acid phenethyl ester (CAPE) induced a majority of cells to differentiate towards the megakaryocytic lineage. Microscopy analysis showed that K562 cells treated with CAPE exhibited characteristic features of physiological megakaryocytic differentiation, including the presence of vacuoles and demarcation membranes. Differentiation of K562 cells treated with CAPE was also accompanied by a net increase in megakaryocytic markers. The transcriptional activity of lactosylceramide α-2,3-sialyltransferase (GM3 synthase) and synthesis of ganglioside GM3 were increased by CAPE treatment. The promoter analysis of GM3 synthase demonstrated that CAPE induced the expression of GM3 synthase mRNA via activation of the cAMP response element-binding protein (CREB), transcription factor in nucleus. Interestingly, the inhibition of ganglioside GM3 synthesis by D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propranol (D-PDMP) and GM3 synthase-siRNA blocked the CAPE-induced expression of the megakaryocytic markers and differentiation of K562 cells. Taken together, these results suggest that CAPE induces ganglioside GM3-mediated megakaryocytic differentiation of human chronic myelogenous cells.

Identifying immune escape mechanisms used by tumors may define strategies to sensitize them to immunotherapies to which they are otherwise resistant. In this study, we show that the antiapoptotic gene API5 acts as an immune escape gene in tumors by rendering them resistant to apoptosis triggered by tumor antigen-specific T cells. Its RNAi-mediated silencing in tumor cells expressing high levels of API5 restored antigen-specific immune sensitivity. Conversely, introducing API5 into API5low cells conferred immune resistance. Mechanistic investigations revealed that API5 mediated resistance by upregulating FGF2 signaling through a FGFR1/PKCδ/ERK effector pathway that triggered degradation of the proapoptotic molecule BIM. Blockade of FGF2, PKCδ, or ERK phenocopied the effect of API5 silencing in tumor cells expressing high levels of API5 to either murine or human antigen-specific T cells. Our results identify a novel mechanism of immune escape that can be inhibited to potentiate the efficacy of targeted active immunotherapies. Cancer Res; 74(13); 3556–66. ©2014 AACR.

The failure of most cancer therapies is the emergence of tumor cells that are refractory to available agent. Here we report that single-modality cancer therapy triggers broad-spectrum cross-resistance to multiple clinical interventions. This multi-modality resistance arises through a core metabolic reprogramming pathway instigated by loss of the ATP synthase subunit ATP5H, which sequentially leads to accumulation of reactive oxygen species and stabilization of HIF-1α under normoxia. Furthermore, we found that NANOG/HDAC1 axis regulates epigenetic loss of ATP5H, this pathway confers tumor cells a stem cell-like phenotype with features associated with metastatic capacity. ATP5H loss in the tumor is strongly linked to failure of therapy, and poor survival in cancer patients. Integration of these biological features provides the best basis for understanding patient outcome in this setting and suggests that loss of ATP5H shapes the tumor resistance to multiple anti-tumor therapy. Citation Format: Suyeon Kim, Kwon-Ho Song, Tae-Woo Kim. HDAC1 -dependent epigenetic loss of ATP5H confers a stem cell-like phenotype with features associated with metastatic capacity through mitochondrial reprogramming [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 807.