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Genetic alterations have been reported for decades in most human embryonic stem cells (hESCs). Survival advantage, a typical trait acquired during long-term in vitro culture, results from the induction of BCL2L1 upon frequent copy number variation (CNV) at locus 20q11.21 and is one of the strongest candidates associated with genetic alterations that occur via escape from mitotic stress. However, the underlying mechanisms for BCL2L1 induction remain unknown. Furthermore, abnormal mitosis and the survival advantage that frequently occur in late passage are associated with the expression of BCL2L1, which is in locus 20q11.21. In this study, we demonstrated that the expression of TPX2, a gene located in 20q11.21, led to BCL2L1 induction and consequent survival traits under mitotic stress in isogenic pairs of hESCs and human induced pluripotent stem cells (iPSCs) with normal and 20q11.21 CNVs. High Aurora A kinase activity by TPX2 stabilized the YAP1 protein to induce YAP1-dependent BCL2L1 expression. A chemical inhibitor of Aurora A kinase and knockdown of YAP/TAZ significantly abrogated the high tolerance to mitotic stress through BCL2L1 suppression. These results suggest that the collective expression of TPX2 and BCL2L1 from CNV at loci 20q11.21 and a consequent increase in YAP1 signaling promote genome instability during long-term in vitro hESC culture.

Naïve and primed pluripotent stem cells recapitulate the peri- and post-implantation development, respectively. Thus, investigation of distinct traits between each pluripotent stem cell type would shed light on early embryonic processes. Herein, by screening a fluorescent probe library, we found that intracellular glycogen led to specific reactivity to CDg4, a glycogen fluorescence sensor, in both human and mouse naïve embryonic stem cells (ESCs). The requirement of constant inhibition of Gsk3β as well as high oxidative phosphorylation (OxPHOS) in naïve compared to primed ESCs was closely associated to high level of intracellular glycogen in naïve ESCs. Both capacity of OxPHOS and stored glycogen, rescued naïve ESCs by transient inhibition of glycolysis, which selectively eliminated primed ESCs. Additionally, naïve ESCs with active OxPHOS were enriched from a mixture with primed ESCs by high reactivity to ATP-Red1, a mitochondrial ATP fluorescence probe. These results indicate the active OxPHOS and high intracellular glycogen as a novel "biomarker" delineating metabolic remodeling during the transition of naïve pluripotency.

Embryonic and epiblast stem cells in pre-and post-implantation embryos are characterized by their naive and primed states, respectively, which represent distinct phases of pluripotency. Thus, the cellular transition from naive to primed pluripotency recapitulates a drastic metabolic and cellular remodeling after implantation to adapt to changes in extracellular conditions. Here, we found that inhibition of Ampk occurred during naive transition with two conventional inhibitors (2i) of the Mek1 and Gsk3b pathways. The accumulation of glycogen due to the inhibition of Gsk3b was responsible for Ampk inhibition, which accounted for high de novo fatty acid synthesis in naive embryonic stem cells (ESCs). The knockout of glycogen synthase 1 (Gys1) in naive ESCs (GKO), resulting in a drastic glycogen loss, led to a robust Ampk activation and lowered the level of fatty acids. GKO lost the cellular characteristics of naive ESCs and rapidly transitioned to a primed state, as evidenced by a decrease in pluripotency markers in teratoma from GKO. The characteristics of GKO were restored by the simultaneous knockout of Ampk. These findings suggest that glycogen in naive ESCs within the blastocyst may act as a signaling molecule for the timely activation of Ampk, thus ultimately contributing to the transition to the epiblast stage.

Precise genome editing of human pluripotent stem cells (hPSCs) is crucial not only for basic science but also for biomedical applications such as ex vivo stem cell therapy and genetic disease modeling. However, hPSCs have unique cellular properties compared to somatic cells. For instance, hPSCs are extremely susceptible to DNA damage, and therefore Cas9-mediated DNA double-strand breaks (DSB) induce p53-dependent cell death, resulting in low Cas9 editing efficiency. Unlike Cas9 nucleases, base editors including cytosine base editor (CBE) and adenine base editor (ABE) can efficiently substitute single nucleotides without generating DSBs at target sites. Here, we found that the editing efficiency of CBE was significantly lower than that of ABE in human embryonic stem cells (hESCs), which are associated with high expression of DNA glycosylases, the key component of the base excision repair pathway. Sequential depletion of DNA glycosylases revealed that high expression of uracil DNA glycosylase (UNG) not only resulted in low editing efficiency but also affected CBE product purity (i.e., C to T) in hESCs. Therefore, additional suppression of UNG via transient knockdown would also improve C to T base substitutions in hESCs. These data suggest that the unique cellular characteristics of hPSCs could determine the efficiency of precise genome editing., Graphical abstract, Park and colleagues found that editing efficiency of CBE is lower than that of ABE in hPSCs, where expressions of DNA glycosylases are higher compared to the differentiated somatic counterparts. High UNG expression in hPSCs significantly affects CBE efficiency and purity. Thus, transient depletion of UNG would be beneficial for improvement of CBE efficiency in hPSCs.

Tissue regeneration after injury involves the dedifferentiation of somatic cells, a natural adaptive reprogramming process that leads to the emergence of injury-responsive cells with fetal-like characteristics in the intestinal epithelium. However, there is no direct evidence that adaptive reprogramming involves a shared molecular mechanism with direct cellular reprogramming. Here, we induced dedifferentiation of intestinal epithelial cells through forced partial reprogrammingin vivousing “Yamanaka factors” (Oct4, Sox2, Klf4, and c-Myc: OSKM). The OSKM-induced dedifferentiation showed similar molecular features of intestinal regeneration, including a rapid transition from homeostatic cell types to injury-responsive-like cell types. These injury-responsive-like cells, sharing a gene signature of revival stem cells and atrophy-induced villus epithelial cells, actively assisted tissue regeneration following ionizing radiation-induced acute tissue damage. In contrast to normal intestinal regeneration, which involves epi-mesenchymal crosstalk through induction ofPtgs2(encoding Cox2) upon injury, the OSKM expression promotes the autonomous production of prostaglandin E2 via epithelialPtgs1(encoding Cox1) expression. These results indicate that prostaglandin synthesis is a common mechanism for intestine epithelial regeneration but involves a different enzyme (Ptgs1for Cox1) when partial reprogramming is directly applied to the intestinal epithelium.

SummaryBackgroundHASPIN, a mitotic kinase for Histone H3, is a promising target for anti-cancer therapy. However, as HASPIN is an atypical kinase with low similarity to eukaryotic protein kinases, development of a HASPIN inhibitor from the conventional pharmacophore of kinase inhibitors would be technically challenging.MethodsChemical modifications of a cytotoxic 4’-thioadenosine analogue with high genotoxicity and multiple kinomescan profiles were performed to produce a novel non-genotoxic kinase inhibitor, LJ4827. The mode of action of this inhibitor with clear anti-cancer activity was inferred based on transcriptomic and chemical similarity to known drugs.ResultsThe specificity and potency of LJ4827 as a HASPIN inhibitor were validated by in vitro kinase screening and subsequent X-ray crystallography. As predicted, LJ4827 treatment delayed mitosis by clear inhibition of the recruitment of Aurora B at the centromere in cancer cells, without a genotoxic response. Through transcriptome analysis of lung cancer patients, PLK1 was predicted as a druggable synergistic partner to complement HASPIN inhibition. Cotreatment with the PLK1 inhibitor BI2536 and LJ4827 led to pronounced cytotoxicity of lung cancers in vitro and in vivo.ConclusionSimultaneous inhibition of both HASPIN and PLK1 is a promising therapeutic strategy for lung cancers.

CDy1 is a powerful tool to distingusih embryonic stem cells for reprogramming studies and regeneration medicine. However, the stem cell selectivity mechanism of CDy1 has not been fully understood. Here, we report ALDH2 and ABCB1 as the molecular targets of CDy1, elucidated by live-cell affinity-matrix and ABC transporter CRISPRa library screening. The two unique orthogonal mechanisms provide the potential of multi-demensional cellular distinction of specific cell types., CDy1 is a powerful tool to distingusih embryonic stem cells for reprogramming studies and regeneration medicine.

SummaryPotential applications of precise genome editing in human pluripotent stem cells (hPSCs), not only for isogenic disease modeling but also for ex vivo stem cell therapy, have urged the application of diverse genome editing tools in hPSCs. However, unlike differentiated somatic cells, the unique cellular properties of hPSCs (e.g., high susceptibility to DNA damage and active DNA repair) largely determine the overall efficiency of editing tools. Considering high demand of prime editors (PE), mostly due to its broad editing coverage compared to base editors, it is important to characterize the key molecular determinants of PE efficiency in hPSCs. Herein, we showed that MSH2 and MSH6, two main components of the MutSα complex of mismatch repair (MMR), are highly expressed in hPSCs and determine PE efficiency in an ‘editing size’-dependent manner. Importantly, loss of MSH2, which disrupts both MutSα and MutSβ complexes, was found to dramatically improve the efficiency of PE from one base to 10 bases, up to 50 folds. In contrast, genetic perturbation of MSH6, which solely abrogates MutSα activity, marginally improved the editing efficiency up to 3 base pairs. The size dependent effect of MSH2 or MSH6 on prime editing in hPSCs not only implies MMR is a major determinant of PE efficiency in hPSCs but also highlights the distinct roles of MutSα and MutSβ in the outcome of genome editing.

Purpose Although epidermal growth factor receptor (EGFR)-activating mutations in non-small cell lung cancer (NSCLC) usually show sensitivity to first-generation EGFR-tyrosine kinase inhibitors (TKIs), most patients relapse because of drug resistance. Heat shock protein 27 (HSP27) has been reported to be involved in the resistance of EGFR-TKIs, although the underlying mechanism is unclear. Here, we explore the mechanisms of HSP27-mediated EGFR TKI resistance and propose novel therapeutic strategies. Methods To determine the mechanism of HSP27 associated gefitinib resistance, differences were assessed using gefitinib-sensitive and -resistant NSCLC cell lines. In vivo xenograft experiments were conducted to elucidate the combinatorial effects of J2, a small molecule HSP27 inhibitor, and gefitinib. Analyses of human NSCLC tissues and PDX tissues were also used for comparison of HSP27 and phosphorylated AKT expression. Results Large-scale cohort analysis of NSCLC cases revealed that HSP27 expression correlated well with the incidence of EGFR mutations and affected patient survival. Increased pAKT and HSP27 was observed in gefitinib-resistant cells compared with gefitinib-sensitive cells. Moreover, increased phosphorylation of HSP27 by gefitinib augmented its protein stability and potentiated its binding activity with pAKT, which resulted in increased gefitinib resistance. However, in gefitinib-sensitive cells, stronger binding activity between EGFR and HSP27 was observed. Moreover, these phenomena occurred regardless of EGFR mutation including secondary mutations, such as T790M. AKT knockdown switched HSP27-pAKT binding to HSP27-EGFR, which promoted gefitinib sensitivity in gefitinib-resistant cells. Functional inhibition of HSP27 yielded sensitization to gefitinib in gefitinib-resistant cells by inhibiting the interaction between HSP27 and pAKT. Conclusions Our results indicate that combination of EGFR-TKIs with HSP27 inhibitors may represent a good strategy to overcome resistance to EGFR-TKIs, especially in cancers exhibiting AKT pathway activation.

Background The requirement of the Mek1 inhibitor (iMek1) during naïve pluripotency maintenance results from the activation of the Mek1-Erk1/2 (Mek/Erk) signaling pathway upon leukemia inhibitory factor (LIF) stimulation. Methods Through a meta-analysis of previous genome-wide screening for negative regulators of naïve pluripotency, Ptpn11 (encoding the Shp2 protein, which serves both as a tyrosine phosphatase and putative adapter), was predicted as one of the key factors for the negative modulation of naïve pluripotency through LIF-dependent Jak/Stat3 signaling. Using an isogenic pair of naïve and primed mouse embryonic stem cells (mESCs), we demonstrated the differential role of Shp2 in naïve and primed pluripotency. Results Loss of Shp2 increased naïve pluripotency by promoting Jak/Stat3 signaling and disturbed in vivo differentiation potential. In sharp contrast, Shp2 depletion significantly impeded the self-renewal of ESCs under primed culture conditions, which was concurrent with a reduction in Mek/Erk signaling. Similarly, upon treatment with an allosteric Shp2 inhibitor (iShp2), the cells sustained Stat3 phosphorylation and decoupled Mek/Erk signaling, thus iShp2 can replace the use of iMek1 for maintenance of naïve ESCs. Conclusions Taken together, our findings highlight the differential roles of Shp2 in naïve and primed pluripotency and propose the usage of iShp2 instead of iMek1 for the efficient maintenance and establishment of naïve pluripotency.

L1 retrotransposons can pose a threat to genome integrity. The host has evolved to restrict L1 replication. However, mechanisms underlying L1 propagation out of the host surveillance remains unclear. Here, we propose an evolutionary survival strategy of L1, which exploits RNA m6A modification. We discover that m6A ‘writer’ METTL3 facilitates L1 retrotransposition, whereas m6A ‘eraser’ ALKBH5 suppresses it. The essential m6A cluster that is located on L1 5′ UTR serves as a docking site for eukaryotic initiation factor 3 (eIF3), enhances translational efficiency and promotes the formation of L1 ribonucleoprotein. Furthermore, through the comparative analysis of human- and primate-specific L1 lineages, we find that the most functional m6A motif-containing L1s have been positively selected and became a distinctive feature of evolutionarily young L1s. Thus, our findings demonstrate that L1 retrotransposons hijack the RNA m6A modification system for their successful replication. L1 is a group of active retrotransposons in humans. Here the authors show that m6A modifications on L1 RNA increase translation efficiency and retrotransposition in human cells. M6A motifs are more enriched in evolutionary young L1s.

Through integration of multiple large database, two oncogenic signatures (YAP conserved and TGFβ‐up signatures) were commonly upregulated in the cancer cell lines with the mesenchymal properties. AXL, the expression of which is highly induced in EMT, contributes the doxorubicin resistance in EMT. Doxorubicin treatment induced YAP‐dependent gene response and promoted AXL expression coordinated with TGFβ‐SMAD4., The acquisition of chemoresistance remains a major cause of cancer mortality due to the limited accessibility of targeted or immune therapies. However, given that severe alterations of molecular features during epithelial‐to‐mesenchymal transition (EMT) lead to acquired chemoresistance, emerging studies have focused on identifying targetable drivers associated with acquired chemoresistance. Particularly, AXL, a key receptor tyrosine kinase that confers resistance against targets and chemotherapeutics, is highly expressed in mesenchymal cancer cells. However, the underlying mechanism of AXL induction in mesenchymal cancer cells is poorly understood. Our study revealed that the YAP signature, which was highly enriched in mesenchymal‐type lung cancer, was closely correlated to AXL expression in 181 lung cancer cell lines. Moreover, using isogenic lung cancer cell pairs, we also found that doxorubicin treatment induced YAP nuclear translocation in mesenchymal‐type lung cancer cells to induce AXL expression. Additionally, the concurrent activation of TGFβ signaling coordinated YAP‐dependent AXL expression through SMAD4. These data suggest that crosstalk between YAP and the TGFβ/SMAD axis upon treatment with chemotherapeutics might be a promising target to improve chemosensitivity in mesenchymal‐type lung cancer.

Serpin family E member 1 (SERPINE1), a serine proteinase inhibitor, serves as an important regulator of extracellular matrix remodeling. Emerging evidence suggests that SERPINE1 has diverse roles in cancer and is associated with poor prognosis. However, the mechanism via which SERPINE1 is induced in cancer has not been fully determined. In order to examine the molecular mechanism of SERPINE1 expression, the present study took advantage of the isogenic pair of lung cancer cells with epithelial or mesenchymal features. Using genetic perturbation and following biochemical analysis, the present study demonstrated that SERPINE1 expression was upregulated in mesenchymal lung cancer cells and promoted cellular invasiveness. Yes‑associated protein (YAP)‑dependent SERPINE1 expression was modulated by treatment with a Rho‑associated protein kinase inhibitor, Y27632. Moreover, TGFβ treatment supported YAP‑dependent SERPINE1 expression, and an enhanced TGFβ response in mesenchymal lung cancer cells promoted SERPINE1 expression. TGFβ‑mediated SERPINE1 expression was significantly attenuated by knockdown of YAP or transcriptional co‑activator with PDZ‑binding motif, suggesting that crosstalk between the TGFβ and YAP pathways underlies SERPINE1 expression in mesenchymal cancer cells.

Aims: A subpopulation of cancer cells, termed cancer stem cells (CSCs), has stemness properties, such as self-renewal and differentiation, which drive cancer recurrence and tumor resistance. CSCs possess enhanced protection capabilities to maintain reduced intracellular levels of reactive oxygen species (ROS) compared with nonstem-like cancer cells. This study investigated whether reductive stress could regulate self-renewal activity in breast CSCs. Results: We found that manifestation of stemness in breast cancer stem-like cells was associated with an elevated production of reduced glutathione (GSH) maintained by upregulation of glutamate cysteine ligase catalytic subunit (GCLC) and consequently, lowered ROS levels. This was accompanied by upregulation of phospho-AMP-activated protein kinase, FoxO3a, and Bmi-1. Notably, expression of nuclear factor erythroid-derived 2-like 2 (Nrf2) protein was substantially increased in cells undergoing sphere formation. We noticed that expression of Bmi-1 was inhibited after introduction of Nrf2 short interfering RNA into MCF-7 mammosphere cells. Silencing of Nrf2 expression suppressed the xenograft growth of subcutaneously or orthotopically injected human breast cancer cells. Innovation: Association between Nrf2 and self-renewal signaling in CSCs has been reported, but the underlying molecular mechanism remains largely unresolved. This study demonstrates the Nrf2-mediated signaling pathway in maintenance of reductive stress in breast CSCs. Conclusion: Nrf2 overactivation in breast CSCs upregulates GCLC expression and consequently enhances GSH biosynthesis with concurrent reduction in intracellular ROS accumulation, thereby provoking the reductive stress. The consequent upregulation of nuclear FoxO3a and its binding to the promoter of the gene encoding Bmi-1 account for the self-renewal activity of breast cancer stem-like cells and their growth in a xenograft mouse model.

Pluripotent stem cells (PSCs) exist in naïve or primed states based on their origin. For in vitro culture, these PSCs require different supplements and growth factors. However, owing to their similar phenotypic features, identifying both cell types without harming cellular functions is challenging. This study reports an electrochemical method that enables simple, label-free, and non-destructive detection of naïve embryonic stem cells (ESCs) derived from mouse ESCs, based on the differences in cellular metabolism. Two major metabolic pathways to generate adenosine triphosphate (ATP)-glycolysis and oxidative phosphorylation (OXPHOS)-were blocked, and it was found that mitochondrial energy generation is the origin of the strong electrochemical signals of naïve ESCs. The number of ESCs is quantified when mixed with primed ESCs or converted from naïve-primed switchable metastable ESCs. The mouse PSCs derived from doxycycline-inducible mouse embryonic fibroblasts (MEFs) are also sensitively identified among other cell types such as unconverted MEFs and primed PSCs. The developed sensing platform operates in a non-invasive and label-free manner. Thus, it can be useful in the development of stem cell-derived therapeutics.

Despite highly effective machinery for the maintenance of genome integrity in human embryonic stem cells (hESCs), the frequency of genetic aberrations during in-vitro culture has been a serious issue for future clinical applications. By passaging hESCs over a broad range of timepoints, we found that mitotic aberrations, such as the delay of mitosis, multipolar centrosomes, and chromosome mis-segregation, were increased in parallel with polyploidy compared to early-passaged hESCs (EP-hESCs) with normal copy number. Through high-resolution genome-wide approaches and transcriptome analysis, we found that culture adapted-hESCs with a minimal amplicon in chromosome 20q11.21 highly expressed TPX2, a key protein for governing spindle assembly and cancer malignancy. Consistent with these findings, the inducible expression of TPX2 in EP-hESCs reproduced aberrant mitotic events, such as the delay of mitotic progression, spindle stabilization, misaligned chromosomes, and polyploidy, suggesting that the increased transcription of TPX2 in culture adapted hESCs could contribute to an increase in aberrant mitosis due to altered spindle dynamics.

Genetic alterations have been reported in most human embryonic stem cells (hESCs) for decades. ‘Survival advantage,’ a typical trait acquired during long-term in vitro culture, results from induction of BCL2L1 upon frequent copy number variation (CNV) at locus 20q11.21 and is one of the strongest candidates associated with genetic alteration via escape from mitotic stress. However, the underlying mechanisms for BCL2L1 induction remain undefined. Furthermore, abnormal mitosis and ‘survival advantage’ frequently occurring in the late passage are respectively associated with the expression of TPX2 and BCL2L1, which are located in locus 20q11.21. In this study, we observed that 20q11.21 CNV was not sufficient for BCL2L1 induction and consequent survival traits in pairs of hESCs and human induced pluripotent stem cells (iPSCs) with normal and 20q11.21 CNVs. Inducible expression of TPX2 and basal TPX2 expression due to leakage of the inducible system in hESCs with normal copy number was sufficient to promote BCL2L1 expression and promoted high tolerance to mitotic stress. High Aurora A kinase activity by TPX2 stabilized YAP1 protein to promote YAP1 dependent BCL2L1 expression. Thus, a chemical inhibitor of Aurora A kinase and knockdown of YAP/TAZ significantly abrogated the aforementioned high tolerance to mitotic stress through BCL2L1 suppression. These results suggest that the collective expression of TPX2 and BCL2L1 from CNV at loci 20q11.21 and a consequent increase in YAP1 signaling would promote genome instability during long-term in vitro hESC culture.

Cell migration, an essential process for normal cell development and cancer metastasis, differs from a simple random walk: the mean-square displacement (〈(Δr)2(t)〉) of cells sometimes shows non-Fickian behavior, and the spatiotemporal correlation function (G(r, t)) of cells is often non-Gaussian. We find that this intriguing cell migration should be attributed to heterogeneity in a cell population, even one with a homogeneous genetic background. There are two limiting types of heterogeneity in a cell population: cellular heterogeneity and temporal heterogeneity. Cellular heterogeneity accounts for the cell-to-cell variation in migration capacity, while temporal heterogeneity arises from the temporal noise in the migration capacity of single cells. We illustrate that both cellular and temporal heterogeneity need to be taken into account simultaneously to elucidate cell migration. We investigate the two-dimensional migration of A549 lung cancer cells using time-lapse microscopy and find that the migration of A549 cells is Fickian but has a non-Gaussian spatiotemporal correlation. We find that when a theoretical model considers both cellular and temporal heterogeneity, the model reproduces all of the anomalous behaviors of cancer cell migration.

Drug repositioning is an attractive alternative to conventional drug development when new beneficial effects of old drugs are clinically validated because pharmacokinetic and safety profiles are generally already available. Since ~ 30% of drugs newly approved by the US food and drug administration (FDA) are developed through drug repositioning, identifying novel usage for existing drugs is an emerging strategy for developing disease treatments. With advances in next-generation sequencing technologies, available transcriptome data related to diseases have expanded rapidly. Harnessing these resources enables a better understanding of disease mechanisms and drug mode of action (MOA), and moves toward personalized pharmacotherapy. In this review, we briefly outline publicly available large-scale transcriptome databases and tools for drug repositioning. We also highlight recent approaches leading to the discovery of novel drug targets, drug response biomarkers, drug indications, and drug MOA.

We have investigated designs for a superconducting single spoke resonator with a resonant frequency of 325 MHz and an optimum beta of 0.51. In this paper, we suggest a balloon variant of a spoke cavity having an end-wall structure, which has a distinct advantage from the viewpoint of multipacting suppression. We determined the geometric parameters of the balloon-shaped single spoke resonator through electromagnetic, multipacting, and mechanical simulations. In addition, we discuss the resonant frequency shifts caused by the cavity processing, the power coupling, and the cavity tuning.

Limited eligibility remains one of major drawbacks of target therapeutics as the oncogenic dependency is only determined by mutation status of a target. In order to extend the eligibility of target therapeutics, transcriptome profiles of patients have been examined to better delineate sensitivity of target therapeutics. In this study, we took advantage of multiple large datasets such as cancer cell line transcriptome data (CCLE), drug response data (CTRP), and gene dependency data (Achilles Project) to determine the sensitivity markers of tyrosine kinase inhibitors currently approved by FDA. In particular, EGFR inhibitors (iEGFR: lapatinib, gefitinib and erlotinib) revealed clear sensitivity cluster of cell line regardless of EGFR mutation status. Comparative analysis between sensitive (iEGFR-S) and resistant (iEGFR-R) cell groups revealed that integrated gene signatures such as chemokine, GPCR, and PI3K-Akt signaling pathway, were predicted as putative determinants of iEGFR susceptibility. Through integrated analysis of gene dependency data, among several Achilles’ targets (of which depletion increases vulnerability), predicted in iEGFR-R cells group, druggable Achilles’ targets (available to accompanied drugs) such as CCR6, AURKA and mTOR were identified as putative targets for sensitizing iEGFR-R group to iEGFR. Following biochemical studies validated the clear sensitizing effect of the pharmacological inhibitor for each predicted target, in the isogenic cell models with acquired iEGFR resistance. In addition, prediction and following biochemical validation, we demonstrated that the CCR6 inhibition significantly attenuated resistance of iEGFR by repressing mitochondrial ROS (mt-ROS), of which induction by iEGFR rescued cell death. These data suggest that integrated-omics analysis would be a useful approach to extend eligibility and improve the efficacy of target therapeutics. Citation Format: Eun-Ji Kwon, Haeseung Lee, Hyuk-Jin Cha. Integrated-omics analysis identifies the druggable achilles targets to sensitize cancer cells with gefitinib resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 71.

HASPIN, a mitotic kinase to phosphorylate Histone H3 at centromere, has been studied as a promising target for anti-cancer therapy. However, as HASPIN belongs to atypical kinase, lacking the Asp-Phe-Gly (DFG) motif, development from the chemical library of kinase inhibitors with conventional pharmacophore, would be technically challenging. In particular, one of adenosine analogues (LJ4827), a potent inhibitor of multi-kinases, showing clear anti-cancer activity in vitro and in vivo, was predicted as a HASPIN inhibitor by computation analysis of its transcriptome profile in cancer cells to drug-omic data set in the connectivity MAP (cMAP) as it shared similar transcriptome profile of 5-iodotubercidin (5ITU). The specificity and potency as HASPIN inhibitor of LJ4827 (IC50 = 0.45 nM) validated by in vitro kinase screening and consequent 3D structure modeling. As expected, treatment of LJ4827 in cancer cell lines efficiently delayed mitotic progression without double strand break (DSB) unlike 5ITU and significantly attenuated Aurora B localization at centromere. Along with clinical significance of HASPIN expression in lung cancer patients, mitotic gene signature closely associated to high expression of HASPIN, revealed the poor prognosis. Additional computational analysis of kinase perturbation data to predict the dependency of mitotic kinase in the absence of HASPIN activity, revealed the synthetic lethal effect of cotreatment of the chemical inhibitor of BUB1, PLK1 or AURKA with LJ4827. These data suggest that combined inhibition of HASPIN with the novel inhibitor and key mitotic kinases for centromere/kinetochore regulation would be effectivity therapeutic approach for cancer therapy. Citation Format: Eun-Ji Kwon, Karishma Mashelkar, Hyuk Woo Lee, Yoon-Ze Shin, Lak Shin Jeong, Hyuk-Jin Cha. Identification of a novel HASPIN inhibitor and the synthetic lethal partner by computational analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3949.

Although human embryonic stem cells (hESCs) are equipped with highly effective machinery for the maintenance of genome integrity, the frequency of genetic aberrations during long-term in vitro hESC culture has been a serious issue that raises concerns over their safety in future clinical applications. By passaging hESCs over a broad range of timepoints, we found that mitotic aberrations, such as the delay of mitosis, multipolar centrosomes, and chromosome mis-segregation, were increased in the late-passaged hESCs (LP-hESCs) in parallel with polyploidy compared to early-passaged hESCs (EP-hESCs). Through high-resolution genome-wide approaches and by following transcriptome analysis, we found that LP-hESCs with a minimal amplicon in chromosome 20q11.21 highly expressed TPX2 (targeting protein for Xklp2), a key protein for governing spindle assembly and cancer malignancy. Consistent with these findings, the inducible expression of TPX2 in EP-hESCs reproduced aberrant mitotic events, such as the delay of mitotic progression, spindle stability, misaligned chromosomes, and polyploidy. This data suggests that the amplification and increased transcription of the TPX2 gene at 20q11.21 could contribute to an increase in aberrant mitosis due to altered spindle dynamics.