Decoding human in vitro terminal erythropoiesis originating from umbilical cord blood mononuclear cells and pluripotent stem cells

Ex vivo red blood cell (RBC) production generates unsatisfactory erythroid cells. A deep exploration into terminally differentiated cells is required to understand the impairments for RBC generation and the underlying mechanisms. Here, we mapped an atlas of terminally differentiated cells from umbilical cord blood mononuclear cells (UCBMN) and pluripotent stem cells (PSC) and observed their dynamic regulation of erythropoiesis at single-cell resolution. Interestingly, we detected a few progenitor cells and non-erythroid cells from both origins. In PSC-derived erythropoiesis (PSCE), the expression of haemoglobin switch regulators (BCL11A and ZBTB7A) were significantly absent, which could be the restraint for its adult globin expression. We also found that PSCE were less active in stress erythropoiesis than in UCBMN-derived erythropoiesis (UCBE), and explored an agonist of stress erythropoiesis gene, TRIB3, could enhance the expression of adult globin in PSCE. Compared with UCBE, there was a lower expression of epigenetic-related proteins (e.g., CASPASE 3 and UBE2O) and transcription factors (e.g., FOXO3 and TAL1) in PSCE, which might restrict PSCE's enucleation. Moreover, we characterized a subpopulation with high proliferation capacity marked by CD99high in colony-forming unit-erythroid cells. Inhibition of CD99 reduced the proliferation of PSC-derived cells and facilitated erythroid maturation. Furthermore, CD99-CD99 mediated the interaction between macrophages and erythroid cells, illustrating a mechanism by which macrophages participate in erythropoiesis. This study provided a reference for improving ex vivo RBC generation.

Nutrient scavenging-fueled growth in pancreatic cancer depends on caveolae-mediated endocytosis under nutrient-deprived conditions

Pancreatic ductal adenocarcinoma (PDAC) is characterized by its nutrient-scavenging ability, crucial for tumor progression. Here, we investigated the roles of caveolae-mediated endocytosis (CME) in PDAC progression. Analysis of patient data across diverse datasets revealed a strong association of high caveolin-1 (Cav-1) expression with higher histologic grade, the most aggressive PDAC molecular subtypes, and worse clinical outcomes. Cav-1 loss markedly promoted longer overall and tumor-free survival in a genetically engineered mouse model. Cav-1-deficient tumor cell lines exhibited significantly reduced proliferation, particularly under low nutrient conditions. Supplementing cells with albumin rescued the growth of Cav-1-proficient PDAC cells, but not in Cav-1-deficient PDAC cells under low glutamine conditions. In addition, Cav-1 depletion led to significant metabolic defects, including decreased glycolytic and mitochondrial metabolism, and downstream protein translation signaling pathways. These findings highlight the crucial role of Cav-1 and CME in fueling pancreatic tumorigenesis, sustaining tumor growth, and promoting survival through nutrient scavenging.

Imaging the Meissner effect in hydride superconductors using quantum sensors

By directly altering microscopic interactions, pressure provides a powerful tuning knob for the exploration of condensed phases and geophysical phenomena1. The megabar regime represents an interesting frontier, in which recent discoveries include high-temperature superconductors, as well as structural and valence phase transitions2-6. However, at such high pressures, many conventional measurement techniques fail. Here we demonstrate the ability to perform local magnetometry inside a diamond anvil cell with sub-micron spatial resolution at megabar pressures. Our approach uses a shallow layer of nitrogen-vacancy colour centres implanted directly within the anvil7-9; crucially, we choose a crystal cut compatible with the intrinsic symmetries of the nitrogen-vacancy centre to enable functionality at megabar pressures. We apply our technique to characterize a recently discovered hydride superconductor, CeH9 (ref. 10). By performing simultaneous magnetometry and electrical transport measurements, we observe the dual signatures of superconductivity: diamagnetism characteristic of the Meissner effect and a sharp drop of the resistance to near zero. By locally mapping both the diamagnetic response and flux trapping, we directly image the geometry of superconducting regions, showing marked inhomogeneities at the micron scale. Our work brings quantum sensing to the megabar frontier and enables the closed-loop optimization of superhydride materials synthesis.

Improved Targeting and Safety of Doxorubicin through a Novel Albumin Binding Prodrug Approach

Human serum albumin (HSA) improves the pharmacokinetic profile of drugs attached to it, making it an attractive carrier with proven clinical success. In our previous studies, we have shown that Caveolin-1 (Cav-1) and caveolae-mediated endocytosis play important roles in the uptake of HSA and albumin-bound drugs. Doxorubicin is an FDA-approved chemotherapeutic agent that is effective against multiple cancers, but its clinical applicability has been hampered by its high toxicity levels. In this study, a doxorubicin-prodrug was developed that could independently and avidly bind HSA in circulation, called IPBA-Dox. We first developed and characterized IPBA-Dox and confirmed that it can bind albumin in vitro while retaining a potent cytotoxic effect. We then verified that it efficiently binds to HSA in circulation, leading to an improvement in the pharmacokinetic profile of the drug. In addition, we tested our prodrug for Cav-1 selectivity and found that it preferentially affects cells that express relatively higher levels of Cav-1 in vitro and in vivo. Moreover, we found that our compound was well tolerated in vivo at concentrations at which doxorubicin was lethal. Altogether, we have developed a doxorubicin-prodrug that can successfully bind HSA, retaining a strong cytotoxic effect that preferentially targets Cav-1 positive cells while improving the general tolerability of the drug.

Improving Bond Strength of Translucent Zirconia Through Surface Treatment With SiO2-ZrO2 Coatings

BACKGROUND

Translucent monolithic zirconia ceramics have been applied in dental clinics due to their esthetic translucent formulations and mechanical properties. Considering inherent ceramic brittleness, adhesive bonding with resin composite increases the fracture resistance of ceramic restorations. However, zirconia is a chemically stable material that is difficult to adhesively bond with resin.

OBJECTIVES

To investigate the influences of SiO2-ZrO2 coatings on adhesive bonding of zirconia and the surface characterization of those coatings.

METHODS AND MATERIALS

Translucent zirconia discs were classified into groups based on surface treatments: CT (control), SB (sandblasting), C21(SiO2:ZrO2=2:1), C11(SiO2:ZrO2=1:1), and C12 (SiO2:ZrO2=1:2) (n=10). Surface characterization of coatings on zirconia were analyzed by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), surface roughness assessment (Ra), X-ray diffraction (XRD), water contact angle (WCA), translucency parameter (TP), and shear bond strength (SBS). Two-way ANOVA for shear bond strength results and ANOVA for Ra and WCA were performed.

RESULTS

SEM images revealed SiO2 islands on zirconia disks coated with SiO2-ZrO2. Surface roughness of C12, C11, and C21 groups was significantly larger than those of groups SB and CT (p<0.05). XRD results showed that phase transformation of zirconia disks was detected only in the SB group. In addition, SiO2-ZrO2 coatings reduced WCA. The translucency decreased only in group C21. Group C11 showed the highest shear bond strength under both aging conditions.

CONCLUSION

SiO2-ZrO2 coating is a promising method to enhance the adhesive resin bonding of translucent zirconia without causing phase transformation of translucent zirconia.

Alkaline-thermal hydrolysate of waste activated sludge as a co-metabolic substrate enhances biodegradation of refractory dye reactive black 5

Aromatic azo dyes possess inherent resistance and are known to be carcinogenic, posing a significant threat to human and ecosystems. Enhancing the biodegradation of azo dyes usually requires the presence of co-metabolic substrates to optimize the process. In addressing the issue of excessive waste activated sludge (WAS) generation, this study explored the potential of utilizing alkaline-thermal hydrolysate of WAS as a co-metabolic substrate to boost the degradation of reactive black 5 (RB5) dyes. The acclimated microbial consortium, when supplemented with the WAS hydrolysate obtained at a hydrolysis temperature of 30 °C, achieved an impressive RB5 decolorization efficiency of 90.3% (pH = 7, 35 °C) with a corresponding COD removal efficiency of 45.0%. The addition of WAS hydrolysate as a co-substrate conferred the consortium with a remarkable tolerance to high dye concentration (1500 mg/L RB5) and salinity levels (4-5%), surpassing the performance of conventional co-metabolic sugars in RB5 degradation. 3D-EEM analysis revealed that protein-like substances rich in tyrosine and tryptophan, present in the WAS hydrolysate, played a crucial role in promoting RB5 biodegradation. Furthermore, the microbial consortium community exhibited an enrichment of dye-degrading species, including Acidovorax, Bordetella, Kerstersia, and Brevundimonas, which dominated the community. Notably, functional genes associated with dye degradation and intermediates were also enriched during the RB5 decolorization and biodegradation process. These findings present a practical strategy for the simultaneous treatment of dye-containing wastewater and recycling of WAS.

Hypoxia-Inducible Transgelin-2 Confers Treatment Resistance through Activation of PI3K/Akt/GSK3β Pathway in Glioblastoma

PURPOSE/OBJECTIVE(S)

Glioblastoma (GBM) patients with wild-type IDH experience worse survival response to the standard treatment of surgery followed by radiation therapy (RT) and temozolomide (TMZ) chemotherapy compared to their mutant IDH counterparts. This treatment has remained relatively ineffective partly due to the highly invasive phenotype of GBM leading to therapeutic resistance and tumor recurrence. Hypoxia is one of the key characteristic features of GBM which results in cancer metastasis and confers treatment resistance. Therefore, it is paramount to identify targets to help overcome hypoxia-induced treatment resistance in glioblastoma. Our lab has identified transgelin-2 (TAGLN2) to be significantly upregulated in IDH-wt GBM through multiple molecular profiling studies. This study aims to understand the mechanisms by which TAGLN2 confers treatment resistance for developing additional treatments for GBM. Additionally, active drug development efforts are also underway to target TAGLN2 for circumventing these therapeutic resistance mechanisms for effective GBM therapy.

MATERIALS/METHODS

RNAi-mediated TAGLN2 knockdown (KD) approach was employed to assess the functions of TAGLN2 in GBM patient-derived xenograft (PDX) cell lines. Series of in vitro functional assays were performed to assess the role of TAGLN2 in these cell lines. Cell proliferation, invasion ± RT and/or TMZ were assessed by MTS and Trans-well invasion assays. Subsequently, WB analysis of oncogenic signaling pathways was performed following Transgelin-2 KD. Co-IP assays and Biacore/SPR analyses were performed to study the binding affinity and kinetics for the interaction of PTEN with TAGLN2. Further, cells were intracranially implanted in nude mice to assess the role of TAGLN2 on tumor growth in vivo.

RESULTS

Conditional KD of TAGLN2 reduces cell proliferation, survival and invasive potential of GBM PDX cell lines. TAGLN2 KD also improved the sensitivity of these cells to both TMZ and radiation in vitro, as assessed by proliferation, survival, clonal expansion, and invasion. Histopathological studies of human GBM tumors and mouse xenograft tumors showed elevated expression of TAGLN2 in the peri-necrotic region of the tumors indicating that TAGLN2 protein level was upregulated by hypoxia. We also show that TAGLN2 is induced in hypoxic microenvironments with GBM PDX cell lines and its overexpression may enhance cellular resistance towards conventional therapy. Subsequently, we also show that hypoxia-induced TAGLN2 activates the PI3K/Akt oncogenic pathway through binding and inhibition of PTEN. Finally, in vivo data using an orthotopic xenograft mouse model shows reduction of tumor growth with knockdown of TAGLN2.

CONCLUSION

Our in vitro and in vivo xenograft studies suggest that TAGLN2 confers treatment resistance to GBM contributing to tumor recurrence. Altogether, TAGLN2 may serve as a potential therapeutically vulnerable target in GBM specifically through its role in cell survival and invasion.

JNTX-101, a novel albumin-encapsulated gemcitabine prodrug, is efficacious and operates via caveolin-1-mediated endocytosis

Albumin is an attractive candidate carrier for the development of novel therapeutic drugs. Gemcitabine has been FDA approved for the treatment of solid tumors; however, new drugs that optimize gemcitabine delivery are not available for clinical use. The aim of this study was to test the efficacy of a novel albumin-encapsulated gemcitabine prodrug, JNTX-101, and investigate whether Cav-1 expression predicts the therapeutic efficacy of JNTX-101. We first determined the treatment efficacy of JNTX-101 in a panel of pancreatic/lung cancer cell lines and found that increases in Cav-1 expression resulted in higher uptake of albumin, while Cav-1 depletion attenuated the sensitivity of cells to JNTX-101. In addition, decreased Cav-1 expression markedly reduced JNTX-101-induced apoptotic cell death in a panel of cells, particularly in low-serum conditions. Furthermore, we tested the therapeutic efficacy of JNTX-101 in xenograft models and the role of Cav-1 in JNTX-101 sensitivity using a Tet-on-inducible tumor model in vivo. Our data suggest that JNTX-101 effectively inhibits cell viability and tumor growth, and that Cav-1 expression dictates optimal sensitivity to JNTX-101. These data indicate that Cav-1 correlates with JNTX-101 sensitivity, especially under nutrient-deprived conditions, and supports a role for Cav-1 as a predictive biomarker for albumin-encapsulated therapeutics such as JNTX-101.

Inhibition of RRM2 radiosensitizes glioblastoma and uncovers synthetic lethality in combination with targeting CHK1

Glioblastoma (GBM) is an aggressive malignant primary brain tumor. Radioresistance largely contributes to poor clinical outcomes in GBM patients. We targeted ribonucleotide reductase subunit 2 (RRM2) with triapine to radiosensitize GBM. We found RRM2 is associated with increasing tumor grade, is overexpressed in GBM over lower grade gliomas and normal tissue, and is associated with worse survival. We found silencing or inhibition of RRM2 by siRNA or triapine sensitized GBM cells to ionizing radiation (IR) and delayed resolution of IR-induced γ-H2AX nuclear foci. In vivo, triapine and IR reduced tumor growth and increased mouse survival. Intriguingly, triapine led to RRM2 upregulation and CHK1 activation, suggesting a CHK1-dependent RRM2 upregulation following RRM2 inhibition. Consistently, silencing or inhibition of CHK1 with rabusertib abolished the triapine-induced RRM2 upregulation. Accordingly, combining rabusertib and triapine resulted in synthetic lethality in GBM cells. Collectively, our results suggest RRM2 is a promising therapeutic target for GBM, and targeting RRM2 with triapine sensitizes GBM cells to radiation and independently induces synthetic lethality of GBM cells with CHK1 inhibition. Our findings suggest combining triapine with radiation or rabusertib may improve therapeutic outcomes in GBM.

Polarizability characteristics of twisted bilayer graphene quantum dots in the absence of periodic moiré potential

Recent studies have documented a rich phenomenology in twisted bilayer graphene (TBG), which is significantly relevant to interlayer electronic coupling, in particular to the cases under an applied electric field. While polarizability measures the response of electrons against applied fields, this work adopts a unique strategy of decomposing global polarizability into distributional contributions to access the interlayer polarization in TBG, as a function of varying twisting angles (θ). Through the construction of a model of twisted graphene quantum dots, we assess distributional polarizability at the first-principles level. Our findings demonstrate that the polarizability perpendicular to the graphene plates can be decomposed into intralayer dipoles and interlayer charge-transfer (CT) components, the latter of which provides an explicit measurement of the interlayer coupling strength and charge transfer potential. Our analysis further reveals that interlayer polarizability dominates the polarizability variation during twisting. Intriguingly, the largest interlayer polarizability and CT driven by an external field occur in the misaligned structures with a size-dependent small angle corresponding to the first appearance of AB stacking, rather than the well-recognized Bernal structures. A derived equation is then employed to address the size dependence on the angle corresponding to the largest values in interlayer polarizability and CT. Our investigation not only characterizes the CT features in the interlayer polarizability of TBG quantum dots, but also sheds light on the existence of the strongest interlayer coupling and charge transfer at small twist angles in the presence of an external electric field, thereby providing a comprehensive understanding of the novel properties of graphene-based nanomaterials.

TRIB1 confers therapeutic resistance in GBM cells by activating the ERK and Akt pathways

GBM (Glioblastoma) is the most lethal CNS (Central nervous system) tumor in adults, which inevitably develops resistance to standard treatments leading to recurrence and mortality. TRIB1 is a serine/threonine pseudokinase which functions as a scaffold platform that initiates degradation of its substrates like C/EBPα through the ubiquitin proteasome system and also activates MEK and Akt signaling. We found that increased TRIB1 gene expression associated with worse overall survival of GBM patients across multiple cohorts. Importantly, overexpression of TRIB1 decreased RT/TMZ (radiation therapy/temozolomide)-induced apoptosis in patient derived GBM cell lines in vitro. TRIB1 directly bound to MEK and Akt and increased ERK and Akt phosphorylation/activation. We also found that TRIB1 protein expression was maximal during G2/M transition of cell cycle in GBM cells. Furthermore, TRIB1 bound directly to HDAC1 and p53. Importantly, mice bearing TRIB1 overexpressing tumors had worse overall survival. Collectively, these data suggest that TRIB1 induces resistance of GBM cells to RT/TMZ treatments by activating the cell proliferation and survival pathways thus providing an opportunity for developing new targeted therapeutics.

[Optical quality with ocular aberrations in young myopic eyes with machine learning]

Objective: The objective of this retrospective study was to employ machine learning techniques to examine age-related traits of ocular aberrations in a substantial population with myopia and myopic astigmatism. Methods: This was a cross-sectional study. Data from a population of myopic and myopic astigmatism patients who underwent wavefront aberration examinations at the Refractive Surgery Center of Tianjin Eye Hospital in Tianjin, China, were collected continuously from January 2013 to July 2017. The data from the right eye of each individual were collected for analysis. Each eye had 32 outcome data points, including age, best-corrected visual acuity (BCVA), lower-order aberrations (spherical diopter, cylindrical diopter, and astigmatic axis), and higher-order aberrations [Zernike coefficients and root mean square (RMS) of the third to sixth order aberrations] were analyzed. Higher-order aberrations were measured by Hartmann-Shack aberrometer. Results: The study included 1 507 subjects (1 507 eyes), comprising of 694 males and 813 females, with a mean age of (23.28±5.45) years. The findings demonstrated a decrease followed by an increase in most of the higher-order aberrations with age between 15-40 years. The minimum value points were observed in the age group of 25-30 years for RMS of total higher-order aberrations, 3rd RMS (with a confidence of 47.74% for range 1), 4th RMS (with a confidence of 86.01% for range 1), and trefoil aberrations (with a confidence of 56.38% for C₃³ and 73.25% for C₃^-3). The minimum value points were also observed in the age group of 30-35 years for primary spherical aberration (with a confidence of 56.10% for C₄⁰) and vertical coma-like aberration (with a confidence of 56.91% for C₃^-1). In contrast, astigmatism with the rule tended to decrease with age, while astigmatism against the rule and oblique astigmatism tended to increase (with a confidence of 88.66%, 84.71%, 81.07%, 79.67%, and 66.35% for astigmatism with the rule in different age groups). Conclusions: As age increases, the population with with-the-rule astigmatism decreases while the population with against-the-rule astigmatism increases. The high-order aberrations are the lowest in the 25-35 age group.

An investigation of the PM2.5 concentrations and cumulative inhaled dose during subway commutes in Changchun, China

Air quality in subway systems is crucial as it affects the health of passengers and staff. Although most tests of PM2.5 concentrations in subway stations have taken place in public areas, PM2.5 is less understood in workplaces. Few studies have estimated the cumulative inhaled dose of passengers based on real-time changes in PM2.5 concentrations as they commute. To clarify the above issues, this study first measured PM2.5 concentrations in four subway stations in Changchun, China, where measuring points included five workrooms. Then, passengers' exposure to PM2.5 during the whole subway commute (20-30 min) was measured and segmented inhalation was calculated. The results showed that PM2.5 concentration in public places ranged from 50 to 180 μg/m3, and was strongly correlated with outdoors. While the PM2.5 average concentration in workplaces was 60 µg/m3, and it was less affected by outdoor PM2.5 concentration. Passenger's cumulative inhalations in single commuting were about 42 μg and 100 μg when the outdoor PM2.5 concentrations were 20-30 μg/m3 and 120-180 μg/m3, respectively. The PM2.5 inhalation in carriages accounted for the largest proportion of the entire commuting, about 25-40%, because of the longer exposure time and higher PM2.5 concentrations. It is recommended to improve the tightness of the carriage and filter the fresh air to improve the air quality inside. The average daily PM2.5 inhaled by staff was 513.53 μg, which was 5-12 times higher than that of passengers. Installing air purification devices in workplaces and reminding staff to take personal protection can positively protect their health.

Abstract 2407: Targeting ribonucleotide reductase subunit 2 (RRM2) to radio-sensitize glioblastoma

Purpose: Despite aggressive multimodality treatments, the median survival of glioblastoma (GBM) remains within the range of 12-15 months after diagnosis with standard-of-care surgery, radiation therapy (RT) and temozolomide (TMZ). Resistance frequently arises, exacerbating the clinical difficulty of treating GBM. Therefore, new or enhanced therapeutic strategies are critically needed. Radiation treatment induces DNA damage that cells must repair for their survival, and DNA repair requires a constant and balanced supply of dNTPs. The ribonucleotide reductase (RNR) catalyzes the rate-limiting step in the production of dNTPs. Therefore, we hypothesize that inhibition of the RRM2 subunit of RNR sensitizes GBM to radiation.

Experimental Design: We analyzed RRM2 expression in GBM via mRNA expression analysis and assessed its correlation with GBM patient clinical outcomes using different public datasets. We examined radiosensitization effects of RRM2 inhibition by either small interfering RNA (siRNA) or RRM2 inhibitor (3-aminopyridine-2-carboxaldehyde thiosemicarbazone; Triapine) known to cross the blood-brain barrier using clonogenic assays in U87MG/EGFRVIII and LN229 GBM cell lines. Human tumor xenografts were generated to explore the radiosensitization effect of Triapine on GBM tumors in vivo. Radiation-induced DNA damage was evaluated via γ-H2AX foci assays and expression levels by western blotting. We further investigated whether CHK1 inhibition with LY2603618-Rabusertib could abrogate the replication stress induced expression of RRM2.

Results: RRM2 is significantly higher expressed in GBM compared to non-tumor tissues (p&lt;0.0001 in both TCGA and Rembrandt datasets), and higher RRM2 expression is significantly associated with higher tumor grade (p&lt;0.0001 in CGGA and p=0.001 in Rembrandt datasets) and worse overall survival (p=0.014 in CGGA dataset). Interestingly, RRM2 inhibition sensitizes GBM cells to radiation treatment in vitro and leads to reductions in tumor growth and significantly increases mice survival in vivo, with acceptable levels of toxicity. Mechanistically, RRM2 inhibition-mediated radiosensitization is associated with higher levels of γ-H2AX expression by westerns, and higher foci counts, indicating higher levels of unresolved DNA damage after radiation. Moreover, we confirmed that Triapine inhibition of RRM2 leads to replication stress which in turn upregulates RRM2 in a CHK1 mediated mechanism, as inhibition of CHK1 abrogated the Triapine induction of RRM2.

Conclusions: These results indicate that RRM2 is upregulated and important for GBM survival after radiation. Moreover, RRM2 inhibition with triapine effectively sensitizes GBM tumors to radiation in vitro and in vivo. Our findings suggest that triapine warrants clinical testing with radiation.

Citation Format: Sergio Corrales-Guerrero, Tiantian Cui, Veronica Castro-Aceituno, Linlin Yang, Haihua Feng, Sindhu Nair, Changxian Shen, Monica Venere, Terence M. Williams. Targeting ribonucleotide reductase subunit 2 (RRM2) to radio-sensitize glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2407.

MicroRNA-575 acts as a novel oncogene via targeting multiple signaling pathways in glioblastoma

PURPOSE

Glioblastoma (GBM) patients currently face poor survival outcomes with an average survival period of <15 months, while only 3-5% of patients survive longer than 36 months. Although the mechanisms of tumorigenesis are still being elucidated, miRNAs are promising candidates to explore as novel and prognostic biomarkers in GBM. In this study, we identified the association between miR-575 expression and overall survival (OS) of primary GBM patients and undertook functional studies to discern the contribution of miR-575 to GBM tumorigenesis.

METHODS

Total RNAs were isolated from 254 FFPE GBM tumor samples and miR expression was assayed (simultaneously) using NanoString Technologies. To determine the association between miR-575 and patients' prognosis, Kaplan-Meier, univariable and multivariable Cox regression analyses were performed. Cell proliferation, colony formation, migration assays were conducted to investigate the function of miR-575 in vitro and in vivo. In silico target gene network analysis was performed to identify the putative targets of miR-575 in GBM, which were further verified by luciferase reporter assay, as well as qPCR and immunoblotting.

RESULTS

Our clinical data (n = 254) show that miR-575 is associated with worse GBM OS by univariable analysis (UVA, HR = 1.27, p-value<0.001) and multivariable (MVA, HR = 1.23, p = 0.007) analysis incorporating critical clinical variables. Functional studies indicated that overexpression of miR-575 significantly increased cell proliferation and migration of GBM cells in vitro, as well as tumor growth in vivo. Subsequent in silico target gene network and mechanistic studies identified CDKN1B/p27 and PTEN, as potential targets of miR-575 in GBM. MicroRNA-575 can also regulate the activity of AKT and ERK pathways in GBM.

CONCLUSION

miR-575 has prognostic value in GBM, with higher expression associating with worse OS of patients, and contributes to GBM tumorigenesis by regulating multiple signaling pathways in GBM.

A Comparison of Clinical Features of Youth with and without Rhinitis Signs and Symptoms Who Are Hospitalized for Headache

Headache and allergic rhinitis (AR) are common in children and often co-occur. We investigated the clinical characteristics of pediatric headaches and the association of AR and chronic headaches. We retrospectively reviewed the medical records of patients admitted to our pediatric inpatient and outpatient clinics with complaints of headache between January 2017 and June 2020 for headache-specific history, AR signs and symptoms, allergy skin prick test, inhalant multiple allergen simultaneous test results, laboratory and imaging findings, and medication history. The patients were divided into three subgroups: AR, non-AR, and headache groups, reporting 45.7% patients with headache alone, 13.7% with additional AR, and 31.6% with abnormal imaging findings, suggesting that headache was combined with sinusitis (24.3%) or mastoiditis (7.3%). Furthermore, 6% of the patients had both AR and sinusitis. Body mass index (BMI) differed significantly between the AR and the non-AR and headache groups (p = 0.03). The BMI differed significantly according to headache severity (p ˂ 0.001). The most common allergen was “dust or mites” (41.1%). Acetaminophen (35.9%) was the most commonly used painkiller. The coexistence of AR and headache may indicate that these conditions share a similar pathophysiology. Better management of allergies may facilitate diagnosis, treatment, and prophylaxis of headaches.

Abstract 4070: Caveolin-1 functions as a potential predictive biomarker for JNTX-101, an albumin encapsulated gemcitabine prodrug

Purpose: Human serum albumin (HSA) is an attractive candidate as a carrier in developing novel albumin-bound nanoparticle therapeutic drugs. Gemcitabine has been used in the treatment of solid tumors, including non-small cell lung, pancreatic, bladder, and breast cancers. Our previous work in pancreatic and lung cancer models demonstrates that caveolin-1 (Cav-1) enhances uptake of albumin and albumin-conjugated drugs. The aim of this study is to investigate whether the presence of Cav-1 expression alters therapeutic efficacy of JNTX-101, a novel albumin encapsulated gemcitabine prodrug.

Experimental design: We first determined the treatment efficacy of JNTX-101 in a panel of 4 pancreatic/lung cancer cell lines (MIAPaCa-2, PANC-1, H23, and HCC15) by alamarBlue cell viability assay. We further established 4 pairs of Cav-1 isogenic cells stably expressing shRNA targeting Cav-1 (shCav-1) or scrambled control shRNA (shCtrl). We investigated whether the absence of Cav-1 expression alters sensitivity of JNTX-101 using alamarBlue cytotoxicity assay and western blotting in both high and low serum conditions. In addition, we tested whether JNTX-101 treatment can alter expression and cellular distribution of Cav-1 as well as other caveolae resident proteins, such as Cav-2 and Cavin-1.

Results: Differences in Cav-1 expression resulted in different uptake of albumin prodrug conjugate and Cav-1 depletion attenuated sensitivity of the cells to JNTX-101. Decreased Cav-1 expression markedly reduced JNTX-101-induced apoptosis in a panel of cells in both high and low serum conditions, but particularly in low serum conditions. In addition, our data showed both serum starvation and JNTX-101 independently increased Cav-1 expression in a time-dependent manner (24hrs, 48hrs, 72hrs) similar to gemcitabine, with peak level at 48 hrs post treatment, while other caveolae resident proteins were minimally affected.

Conclusions: Our preliminary results suggest that JNTX-101 effectively inhibits cell viability in pancreatic/lung cancer cells and Cav-1 expression dictates sensitivity to JNTX-101, at least partially through reduced apoptotic cell death. These data indicate that Cav-1 may be a potential predictive biomarker of JNTX-101 sensitivity, especially in nutrient deprived conditions. Further study will be performed to explore the impact of Cav-1 expression on JNTX-101 sensitivity in mouse models of pancreatic/lung cancer.

Citation Format: Tiantian Cui, Sergio Corrales-Guerrero, Dan Maneval, Curtis Monnig, Patrick Kearney, Sam Ellis, Terence M. Williams. Caveolin-1 functions as a potential predictive biomarker for JNTX-101, an albumin encapsulated gemcitabine prodrug [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 4070.

Improvement Using Planomics Features on Prediction and Classification of Patient-Specific Quality Assurance Using Head and Neck Volumetric Modulated Arc Therapy Plan

Purpose: This study aimed to evaluate the utility of a new plan feature (planomics feature) for predicting the results of patient-specific quality assurance using the head and neck (H&N) volumetric modulated arc therapy (VMAT) plan. Methods: One hundred and thirty-one H&N VMAT plans in our institution from 2019 to 2021 were retrospectively collected. Dosimetric verification for all plans was carried out using the portal dosimetry system integrated into the Eclipse treatment planning system based on the electronic portal imaging devices. Gamma passing rates (GPR) were analyzed using three gamma indices of 3%/3 mm, 3%/2 mm, and 2%/2 mm with a 10% dose threshold. Forty-eight conventional features affecting the dose delivery accuracy were used in the study, and 2,476 planomics features were extracted based on the radiotherapy plan file. Three prediction and classification models using conventional features (CF), planomics features (PF), and hybrid features (HF) combining two sets of features were constructed by the gradient boosting regressor (GBR) and Ridge classifier for each GPR of 3%/3 mm, 3%/2 mm, and 2%/2 mm, respectively. The absolute prediction error (APE) and the area under the curve (AUC) were adopted for assessing the performance of prediction and classification models. Results: In the GPR prediction, the average APE of the models using CF, PF, and HF was 1.3 ± 1.2%/3.6 ± 3.0%, 1.7 ± 1.5%/3.8 ± 3.5%, and 1.1 ± 1.0%/4.1 ± 3.1% for 2%/2 mm; 0.7 ± 0.6%/2.0 ± 2.0%, 1.0±1.1%/2.2 ± 1.8%, and 0.6 ± 0.6%/2.2 ± 1.9% for 3%/2 mm; and 0.4 ± 0.3%/1.2 ± 1.2%, 0.4±0.5%/1.3 ± 1.0%, and 0.3±0.3%/1.2 ± 1.1% for 3%/3 mm, respectively. In the regression prediction, three models give a similar modeling performance for predicting the GPR. The classification results were 0.67 ± 0.03/0.66 ± 0.07, 0.77 ± 0.03/0.73 ± 0.06, and 0.78 ± 0.02/0.75 ± 0.04 for 3%/3 mm, respectively. For 3%/2 mm, the AUCs of the training and testing cohorts were 0.64 ± 0.03/0.62 ± 0.07, 0.70 ± 0.03/0.67 ± 0.06, and 0.75 ± 0.03/0.71 ± 0.07, respectively, and for 2%/2 mm, the average AUCs of the training and testing cohorts were 0.72 ± 0.03/0.72 ± 0.06, 0.78 ± 0.04/0.73 ± 0.07, and 0.81 ± 0.03/0.75 ± 0.06, respectively. In the classification, the PF model has a better classification performance than the CF model. Moreover, the HF model provides the best result among the three classifications models. Conclusions: The planomics features can be used for predicting and classifying the GPR results and for improving the model performance after combining the conventional features for the GPR classification.

A novel protein-drug conjugate, SSH20, demonstrates significant efficacy in caveolin-1-expressing tumors

In recent years, human serum albumin (HSA) has been characterized as an ideal drug carrier in the cancer arena. Caveolin-1 (Cav-1) has been established as the principal structural protein of caveolae and, thus, critical for caveolae-mediated endocytosis. Cav-1 has been shown to be overexpressed in cancers of the lung and pancreas, among others. We found that Cav-1 expression plays a critical role in both HSA uptake and response to albumin-based chemotherapies. As such, developing a novel albumin-based chemotherapy that is more selective for tumors with high Cav-1 expression or high levels of caveolar-endocytosis could have significant implications in biomarker-directed therapy. Herein, we present the development of a novel and effective HSA-SN-38 conjugate (SSH20). We find that SSH20 uptake decreases significantly by immunofluorescence assays and western blotting after silencing of Cav-1 expression through RNA interference. Decreased drug sensitivity occurs in Cav-1-depleted cells using cytotoxicity assays. Importantly, we find significantly reduced sensitivity to SSH20 in Cav-1-silenced tumors compared to Cav-1-expressing tumors in vivo. Notably, we show that SSH20 is significantly more potent than irinotecan in vitro and in vivo. Together, we have developed a novel HSA-conjugated chemotherapy that is potent, effective, safe, and demonstrates improved efficacy in high Cav-1-expressing tumors.

Oxypeucedanin is a mechanism-based inactivator of CYP2B6 and CYP2D6

BACKGROUND

Herbal medicine Angelica dahurica is widely employed for the treatment of rheumatism and pain relief in China. Oxypeucedanin is a major component of the herb.

OBJECTIVES

The objectives of this study are aimed at the investigation of mechanism-based inactivation of CYP2B6 and CYP2D6 by oxypeucedanin, characterization of the reactive metabolites associated with the enzyme inactivation, and identification of the P450s participating in the bioactivation of oxypeucedanin.

METHODS

Oxypeucedanin was incubated with liver microsomes or recombinant CYPs2B6 and 2D6 under designed conditions, and the enzyme activities were measured by monitoring the generation of the corresponding products. The resulting reactive intermediates were trapped with GSH and analyzed by LC-MS/MS.

RESULTS

Microsomal incubation with oxypeucedanin induced a time-, concentration-, and NADPH-dependent inhibition of CYPs2B6 and 2D6 with kinetic values of KI/kinact 1.82 µM/0.07 min-1 (CYP2B6) and 8.47 µM/0.044 min-1 (CYP2D6), respectively. Ticlopidine and quinidine attenuated the observed time-dependent enzyme inhibitions. An epoxide and/or γ-ketoenal intermediate(s) derived from oxypeucedanin was/were trapped in microsomal incubations. CYP3A4 was the primary enzyme involved in the bioactivation of oxypeucedanin.

CONCLUSION

Oxypeucedanin was a mechanism-based inactivator of CYP2B6 and CYP2D6. An epoxide and/or γ-ketoenal intermediate(s) may be responsible for the inactivation of the two enzymes.

Mild Hypoxia Enhances the Expression of HIF and VEGF and Triggers the Response to Injury in Rat Kidneys

Background

Hypoxia contributes to a cascade of inflammatory response mechanisms in kidneys that result in the development of renal interstitial fibrosis and subsequent chronic renal failure. Nonetheless, the kidney possesses a self-protection mechanism under a certain degree of hypoxia and this mechanism its adaptation to hypoxia. As the hypoxia-inducible factor (HIF)–vascular endothelial growth factor (VEGF) axis is a key pathway for neovascularization, the activation of this axis is a target for renal hypoxia therapies.

Methods

Sprague–Dawley rats were exposed to normobaric hypoxia and subdivided into three groups, namely group A (21% O₂), group B (10% O₂), and group C (7% O₂). Renal tissue samples were processed and analyzed to determine pathological morphological changes, the expression of HIF, VEGF, inflammation factor and vascular density.

Results

We found that as the duration of hypoxia increased, destructive changes in the kidney tissues became more severe in group C (7% O₂). In contrast, the increased duration of hypoxia did not exacerbate kidney damage in group B (10% O₂). As the hypoxia was prolonged and the degree of hypoxia increased, the expression of HIF-1α increased gradually. As hypoxia time increased, the expression of VEGF increased gradually, but VEGF expression in group B (10% O₂) was the highest. Group C (7% O₂) had higher levels of IL-6, IL-10, and TNF-alpha. Additionally, the highest vascular density was observed in group B.

Conclusion

These findings suggest that activating the HIF–VEGF signaling pathway to regulate angiogenesis after infliction of hypoxic kidney injury may provide clues for the development of novel CKD treatments.

Pattern of Recurrence in 428 Patients With Thoracic Esophageal Squamous Cell Carcinoma After Radical Surgery and Its Implication in Postoperative Radiotherapeutic Clinical Target Volume

Purpose

This study aimed to analyze the recurrence patterns of thoracic esophageal squamous cell carcinoma (ESCC) after radical surgery, and to understand its implication in the clinical target volume (CTV) design of postoperative radiotherapy (PORT) in patients with ESCC.

Methods and materials

A total of 428 recurrent ESCC patients after radical surgery between 2014 and 2018 were included in this study. Recurrence patterns, especially anastomotic and regional lymph node recurrence (LNR), were analyzed. A T-shaped CTV were proposed for PORT and were evaluated whether it could cover most of regional LNR.

Results

These patients all experienced anastomotic and/or regional LNR. Among the 428 patients, 27 cases (6.3%) had anastomotic recurrence only, and184 cases (43.0%) had LNR only. Those sites with an LNR rate higher than 15% in upper thoracic ESCC were as follows: No.101, No.104R, No.104L, No.106recR, No.106recL, No.106pre, No.106tb, No.107, and No. 109. Those with middle thoracic ESCC were as follows: No.104R, No.104L, 106recR, No.106recL, No.106pre, No.106tb, and No.107. Lastly, individuals with lower thoracic ESCC were as follows: No.104L, 106recR, No.106recL, No. 106pre, No. 106tb, No.107, and abdominal No. 3. The proportion of LNR not included in the proposed T-shaped CTV was 12.5% (1/8), 4.7% (6/128), and 10.4% (5/48) in the upper, middle, and lower thoracic segments, respectively.

Conclusions

LNR was the most common type of local-regional recurrence in patients after radical surgery. Supraclavicular, superior and middle mediastinal lymph nodes had the highest recurrence rate, the rate of LNR which was outside T-shaped PORT CTV we proposed was less than 15%.

A Novel miR-146a-POU3F2/SMARCA5 Pathway Regulates Stemness and Therapeutic Response in Glioblastoma

Rapid tumor growth, widespread brain-invasion, and therapeutic resistance critically contribute to glioblastoma (GBM) recurrence and dismal patient outcomes. Although GBM stem cells (GSC) are shown to play key roles in these processes, the molecular pathways governing the GSC phenotype (GBM-stemness) remain poorly defined. Here, we show that epigenetic silencing of miR-146a significantly correlated with worse patient outcome and importantly, miR-146a level was significantly lower in recurrent tumors compared with primary ones. Further, miR-146a overexpression significantly inhibited the proliferation and invasion of GBM patient-derived primary cells and increased their response to temozolomide (TMZ), both in vitro and in vivo. Mechanistically, miR-146a directly silenced POU3F2 and SMARCA5, two transcription factors that mutually regulated each other, significantly compromising GBM-stemness and increasing TMZ response. Collectively, our data show that miR-146a-POU3F2/SMARCA5 pathway plays a critical role in suppressing GBM-stemness and increasing TMZ-response, suggesting that POU3F2 and SMARCA5 may serve as novel therapeutic targets in GBM. IMPLICATIONS: miR-146a predicts favorable prognosis and the miR-146a-POU3F2/SMARCA5 pathway is important for the suppression of stemness in GBM.

Graphene-based temperature sensors suspended by anodic aluminum oxide

In this paper, we investigate the substrate effect in graphene temperature sensors. Recently, there have been many research studies done on temperature sensors using the nanofabrication technique. However, the sensitivity and response time need to be improved. In this study, we propose a new type of temperature sensor that consists of graphene and Anodic Aluminum Oxide (AAO). In this device, graphene and AAO are used as the sensing material and the substrate, respectively. We characterize the sensitivity and the response time using the experimental results and simulation data. The real-time resistance change of graphene is monitored depending on the temperature, and the response time is also analyzed by COMSOL Multiphysics. To confirm the porous substrate effect, we compare the device performance of the AAO substrate to the performance of the glass substrate. From these results, the suspended graphene on the AAO substrate shows about two times higher sensitivity and a much faster response time than the glass substrate.

Association of genetic and environmental factors with dental caries among adolescents in south China: A cross-sectional study

AIM

The objective of this study was to investigative genetic and environmental factors that contribute to caries susceptibility among adolescents in south China.

MATERIALS AND METHODS

A cross-sectional study was conducted among 1055 adolescents aged 13-14 years old in south China. The International Caries Detection and Assessment System (ICDAS) was used to identify caries. Environmental variables were analysed by regression models. Twenty-three single nucleotide polymorphisms (SNPs) in 14 genes were identified from saliva samples. Regression analysis was used for the evaluation of effects of SNP markers using the minor allele as the effect allele.

RESULTS

Our results suggest that gender, Cariostat score and Plaque Index were associated with dental caries. After the adjustment by age and gender, the G allele in AMBN (rs13115627) nominally was a protective factor for caries under additive model (P=0.028; OR=0.782; 95% CI, 0.627-0.974). However, the association did not meet the Bonferroni correction significance cut-off for multiple testing.

CONCLUSION

Gender, Cariostat score and Plaque Index were associated with dental caries in this population. No selected SNPs showed a significant association with dental caries under either additive model or dominance model.

Intrinsic Fluoride Tolerance Regulated by a Transcription Factor

Fluoride facilitates the remineralization of dental hard tissues and affects bacterial activities. Therefore, it is extensively used as an anti-caries agent in clinical practice and daily life. Although some studies focused on understanding Streptococcus mutans' response to fluoride, the mechanism regulating intrinsic fluoride tolerance is not yet clear. Since the TetR family of transcription factors is associated with multidrug resistance, our aim was to evaluate whether they are related to fluoride tolerance in S. mutans. A mutant library including each S. mutans TetR gene was constructed and the transcription factor fluoride related transcriptional regulator (FrtR) was identified. The in-frame deletion of the S. mutans frtR gene resulted in decreased cell viability under fluoride in both the planktonic state and single-/dual-species biofilms. This in-frame frtR mutant was used for RNA-sequencing and the fluoride related permease gene (frtP) was found as 1 of the downstream genes directly regulated by FrtR. The recombinant FrtR protein was purified, and conserved DNA binding motifs were determined using electrophoretic mobility shift and DNase I footprinting assays. Finally, a series of mutant and complement strains were constructed to perform the minimum inhibitory concentration (MIC) assays, which indicated that frtP upregulation led to the increase of fluoride sensitivity. Collectively, our results indicate that FrtR is an important transcription factor regulating the frtP expression in S. mutans, thus affecting the intrinsic fluoride tolerance. Therefore, this study provides novel insights into a potential target to increase the S. mutans sensitivity to fluoride for a better prevention of dental caries.

The glymphatic system delivery enhances the transduction efficiency of AAV1 to brain endothelial cells in adult mice

BACKGROUND

Recombinant adeno-associated virus (rAAV) is increasingly applied in neuroscience research or gene therapy. However, there is no simple and efficient tool for specific transfection of rAAV into cerebrovascular tissues. It has been reported that fluorescent tracers or beta-amyloid protein can enter the brain through perivascular spaces, named as "glymphatic system". The purpose of this study was to explore whether rAAV could transduce the cerebral vasculature through the glymphatic pathway.

NEW METHOD

An AAV1-GFP vector suspension (15 μL) was injected into the intracisternal space of anesthetized mice (n = 2) and 5 μl was injected into the bulbus medullae (n = 2). As controls, 15 μl of artificial cerebrospinal fluid (aCSF) was injected into the cisterna magna. The endothelial specific transduction was verified by Glut1 or PDGFRβ immunofluorescent staining. Immunofluorescence images for all groups were captured with a laser microscope.

RESULTS

It was observed that infection with rAAV1 vectors encoding green fluorescence protein resulted in a successful cerebrovascular transduction when injected into cisterna magna, compared to aCSF or intra-parenchymal injection at 30 days post-transduction in adult mice. In addition, GFP was co-localized with Glut1 based on immuno-fluorescence. These results indicate that glymphatic system delivery enhances the transduction efficiency of AAV1 to brain endothelial cells.

COMPARISON WITH EXISTING METHODS

The AAV1 vector can simply and efficiently transduce the cerebral endothelial cells through the glymphatic pathway.

CONCLUSION

The findings of this study reveal that rAAV1-based vectors have high application potential for endothelial-targeted neurologic disease research or gene-based therapies.

Piperine Is a Mechanism-Based Inactivator of CYP3A

Piperine (PPR) is the representative alkaloid component of the piper species (family: Piperaceae). Our rapid screening study found PPR caused time-dependent inhibition of cytochrome P450s (CYP) 3A and 2D6, and CYP3A was inactivated the most. Further study demonstrated that PPR is a time-, concentration-, and NADPH-dependent inhibitor of CYP3A, and significant loss (49.5% ± 3.9%) of CYP3A activity was observed after 20minute incubations with 80 μM PPR at 37°C. The values of K _I and k _inact were 30.7 μM and 0.041 minutes^-1, respectively. CYP3A competitive inhibitor ketoconazole showed protective effect against the enzyme inactivation. Superoxide dismutase/catalase and GSH displayed minor protection against the PPR-caused enzyme inactivation. Ferricyanide partially reduced the enzyme inhibition by PPR. Additionally, NADPH-dependent formation of reactive metabolites from PPR were found in human liver microsomal incubation mixtures. An ortho-quinone intermediate was trapped by NAC in microsomal incubations with PPR. DM-PPR, demethylene metabolite of PPR, showed weak enzyme inactivation relative to that caused by PPR. It appears that both carbene and ortho-quinone intermediates were involved in the inactivation of CYP3A caused by PPR. SIGNIFICANCE STATEMENT: CYP3A subfamily members (mainly CYP3A4 and CYP3A5) play a critical role in drug metabolism. Piperine (PPR), a methylenedioxyphenyl derivative combined with an unsaturated ketone, is the major active ingredient of pepper. PPR revealed time-, concentration-, and NADPH-dependent inhibitory effect on CYP3A. Carbene and quinone metabolites were both involved in the observed CYP3A inactivation by PPR. Apparently, the unsaturated ketone moiety did not participate in the enzyme inactivation. The present study sounds an alert of potential risk for food-drug interactions.

Abstract GMM-017: UPREGULATION OF MIR-328 CONTRIBUTES TO OVARIAN CANCER STEM CELL MAINTENANCE BY DOWNREGULATING DDB2

Cancer stem cells (CSCs) are a particular subpopulation of cells that are characterized by self renewal, differentiation and enhanced tumorigenicity. They are responsible for tumor metastasis, relapse and development of drug resistance. Thus, eradication of CSCs is essential for improved patient prognosis. Micro RNAs are a group of small non-coding, endogenous RNAs that are found to regulate cancer stem cell characteristics by binding to mRNA in a sequence specific manner. In ovarian cancers, a wide array of Micro RNAs have been found to show differential expression of which miR328-3p deserves special mention. In this study, a Micro RNA Nanostring profile analysis reveals a significant upregulation of miR-328-3p in ovarian cancer stem cells isolated from both ovarian cancer cell lines and primary ovarian tumors as compared to their corresponding bulk cells. Moreover, it was found that inhibition of miR-328 limited the CSC population in ovarian cancer cells whereas overexpression of miR-328 enriched the CSC population, thus accounting for miR-328 as an onco-miRNA. The upregulation of miR-328 not only increased the percentage of ALDH+ cells in ovarian cancer bulk cells, but also increased the tumorigenicity and sphere formation ability. This was supported by the orthotopic ovarian xenograft assay. Further investigation revealed that reduced phosphorylation of Erk in ovarian cancer stem cells owing to reduced levels of Reactive Oxygen species (ROS) could be a prospective mechanism behind elevated miR328 expression and maintenance of CSC characteristics. Inhibition of phosphorylated Erk expression in ovarian cancer bulk cells by use of commercially available Erk inhibitor, U0126, led to a significant increase in miR328 expression. Simultaneously, upregulation of phosphorylated Erk in ovarian cancer stem cells not only reduced miR328 expression, but also displayed a significant reduction in expression of cancer stem cell markers (Oct4, Sox2, Nanog), sphere formation ability and tumorigenesis. We obtained a similar trend of results on regulating the expression of pErk by use of Reactive Oxygen Species to ovarian cancer cells. These data further helped us confirm our speculation that reduced ROS promotes the maintenance of CSCs characteristics through inactivation of Erk signalling pathway. Besides, we also identified DDB2 as a direct target of miR328. Our previous findings demonstrate that DDB2 is able to limit ovarian CSC population by disrupting their self renewal capacity. Thus, we conclude that elevated miR328 in ovarian CSCs, resulting from inactivated Erk1/2 activity, is responsible for maintenance of stemness by inhibition of DDB2 expression. Targeting miR-328 could therefore be a novel therapeutic strategy to eradicate CSCs in ovarian cancer.

Citation Format: Amit Kumar Srivastava, Tiantian Cui, Ananya Banerjee, Chunhua Han, Shurui Cai, Lu Liu, Dayong Wu1, Ri Cui, Zaibo Li, Xiaoli Zhang, Guozhen Xie, Selvendiran Karuppalyah, Adam Karpf, Jinsong Liu, David Cohn, Qi-En Wang. UPREGULATION OF MIR-328 CONTRIBUTES TO OVARIAN CANCER STEM CELL MAINTENANCE BY DOWNREGULATING DDB2 [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr GMM-017.

Abstract NT-100: PARPI-INDUCED ALDH1A1 EXPRESSION CONTRIBUTES TO PARPI RESISTANCE IN OVARIAN CANCER CELLS

Ovarian cancer (OC) is one of the most lethal female malignancy which accounts for just 2.5% of female cancer cases but 5% of deaths because of low survival. 90% of OC are epithelial ovarian cancer (EOC), with an overall 5-year relative survival rate of 47% and only 29% for patients diagnosed with distant-stage. 20% of OC cases are estimated to be due to inherited mutations that confer elevated risk, especially cancer susceptibility genes BRCA1 and BRCA2. PARP inhibitors (PARPi) are novel and promising cancer-targeted drugs. PAPRi are approved by FDA for clinical treatment of advanced EOC patients with BRCA1/2 gene mutation. However, patients gradually gained resistance to PARPi with continuously increased recurrence rate (&gt;90%). Thus, understanding the mechanism underlying PARPi resistance is an urgent need for improving the PARPi efficacy. Aldehyde dehydrogenase (ALDH) activity is considered as a cancer stem cell (CSC) marker and also relative to drug resistance. However, the relationship between ALDH activity and PAPPi resistance remains unclear. In this study, we generated two olaparib-resistant EOC cell lines by continuously treating BRCA2-mutated PEO1 and Kuramochi cell lines for 6 months, and found that these resistant cell lines exhibited higher ALDH activity compared to their corresponding parent cell lines. In addition, short-term treatment of PEO1 and Kuramochi cells with olaparib (7 days) also increased the ALDH+ cell population in these cells, and olaparib-induced ALDH--to-ALDH+ conversion contributed to the expansion of the ALDH+ cell population after olaparib treatment. qRT-PCR analysis demonstrated that ALDH1A1 is the major gene in the ALDH gene family that was induced by olaparib. Overexpression of ALDH1A1 increased olaparib resistance in a panel of EOC cells lines including both BRCA2-muated and BRCA2-wild type cell lines. In summary, our data indicate that olaparib is able to induce ALDH1A1 gene expression, which results in the enhanced ALDH activity. The enhanced ALDH activity can contribute to olaparib resistance in BRCA2-mutated EOC cells.

Citation Format: Lu Liu, Shurui Cai, Chunhua Han, Ananya Benerjee, Dayong Wu, Tiantian Cui, Guozhen Xie, Yanfang Zheng, and Qi-En Wang. PARPI-INDUCED ALDH1A1 EXPRESSION CONTRIBUTES TO PARPI RESISTANCE IN OVARIAN CANCER CELLS [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr NT-100.

MiR-363-3p modulates cell growth and invasion in glioma by directly targeting pyruvate dehydrogenase B

OBJECTIVE

This study is designed to investigate the role of miR-363-3p in the cancer development of glioma.

PATIENTS AND METHODS

The expression of miR-363-3p in glioma and adjacent noncancerous tissue was measured using quantitative RT-PCR. The expression of a target gene of miR-363-3p, pyruvate dehydrogenase B (PDHB), was determined by Western blot. The level of miR-363-3p was increased or decreased by transfected with miR-363-3p mimic or miR-363-3p inhibitor, respectively. The impact of miR-363-3p on cell growth, apoptosis and invasion was determined by CCK-8 (Cell Counting Kit) assay, flow cytometry, and transwell assay. The role of PDHB in mediating the oncogenic activities was demonstrated by co-transfected PDHB vector and miR-363-3p mimic.

RESULTS

Our results have shown that miR-3663-3p level was significantly higher in glioma tissue. Furthermore, miR-363-3p functions as onco-miRNA, promotes cell proliferation, protects against apoptosis, and enhances invasion by directly targeting PDHB.

CONCLUSIONS

MiR-363-3p is an onco-miRNA, which can be considered as a potential therapeutic target in glioma.

RDNA-14. RADIATION-INDUCED miR-4516 CONTRIBUTES TO RADIO-RESISTANCE AND PROMOTES AGGRESSIVE PHENOTYPE IN GLIOBLASTOMA

BACKGROUND

Glioblastoma is the most aggressive brain tumor with poor prognosis despite the best available treatment. MicroRNAs (miRNAs) are emerging as promising, novel prognostic biomarkers and therapeutic targets in glioblastoma. In a previous study, we demonstrated that miR-4516 predicts poor prognosis and functions as an oncogene in glioblastoma. Aim of the current study is to examine the role miR-4516 in radiation resistance and identify downstream targets contributing to this phenotype

METHODS

Radiosensitization was evaluated by cell viability and clonogenic assays. Cell apoptosis was evaluated using flow cytometry and immunoblotting. Potential targets of miR-4516 were identified using bioinformatic analysis (Targetscan and miRDB) and confirmed by luciferase reporter assays. Results were validated using immunoblotting. miR-4516 expression in glioblastoma cell lines after radiation treatment was quantified by qRT-PCR.

RESULTS

Expression of miR-4516 was increased up to 15 fold following radiation treatment, peaking at around 15min-60 min in primary and established glioblastoma cell lines including GBM 08-387, GBM 30 and U87-MG. Furthermore, inhibition of miR-4516 sensitized GBM 08-387, GBM30 and U87-MG cells to radiation in comparison to control groups as determined by cell viability and clonogenic assays. Further, miR-4516 inhibition induced apoptosis in these cell lines following radiation treatment. While conducting mechanistic studies, we found that the tumor-promoting function of miR-4516 was, in part, mediated by inhibition of p21 and PTPN14, two direct targets of miR-4516

CONCLUSION

Our data suggest that radiation induces the expression of miR-4516 in glioblastoma cell lines. This miRNA plays a critical role in radio-resistance and promotes aggressive phenotypes in glioblastoma and therefore, functional analyses of its target pathways may uncover novel therapeutically vulnerable target(s) in glioblastoma. FUNDING: R01CA108633, R01CA169368, RC2CA148190, U10CA180850-01(NCI), Brain Tumor Funders Collaborative Grant, and OSU-CCC (all to AC). The Ton and Patricia Bohnenn Fund for Neuro_Oncology Research (to PR).

CSIG-30. miR-146a INHIBITS TUMORIGENESIS AND INDUCES TEMOZOLOMIDE SENSITIVITY VIA AFFECTING CANCER STEM CELL PROPERTIES IN GBM

BACKGROUND

Glioblastomas (GBMs) are the most aggressive primary brain tumors, with an average survival time of less than 15 months. miRNAs are emerging as promising and novel biomarkers in GBM. The aims of this study are: 1) to investigate novel miRNAs biomarkers that affect tumorigenesis and therapeutic sensitivity, and 2) to study the underlying molecular mechanisms in GBM.

METHODS

Nanostring v3 was performed followed by univariable (UVA) and multivariable (MVA) analyses. Functional studies were conducted to define the role of miR-146a in GBM tumorigenesis and therapeutic response and the molecular mechanisms were investigated.

RESULTS

UVA analyses demonstrated that miR-146a is one of the top miRNAs that correlated with better prognosis in GBM patients (p=9.21E-05), which was independent of MGMT promoter methylation by MVA analyses (p< 0.001). miR-146a expression was significantly downregulated in recurrent GBM tumors compared with the paired primary GBM tumors (p=0.003). Overexpression of miR-146a significantly inhibited tumor cell growth and sensitized patient-derived primary GBM cells to temozolomide (TMZ) treatment in vitro, and showed statistically significant smaller tumor size (p< 0.01) and prolonged survival (p=0.001) in vivo. In addition, miR-146a is downregulated in glioma cancer stem cells, and overexpression of miR-146a significantly affected glioma cancer stem cell self-renewal. We also found that overexpression of miR-146a significantly inhibited the NF-κB, AKT, and ERK pathways.

CONCLUSION

Our data suggest, for the first time, that miR-146a predicts favorable prognosis for GBM patients and sensitizes primary GBM cells to TMZ treatment in vitro and in vivo through regulating glioma stem cells. Importantly, miR-146a may prove to be a master switch shutting off AKT, NF-κB, as well as other pathways and may overcome redundancies among these pathways leading to resistance. FUNDING: Bohnenn Fund (to PR), R01CA108633, R01CA169368, U10CA180850-01(NCI), Brain Tumor Funders Collaborative Grant, and The Ohio State University CCC (all to AC).

ALDH1A1 Contributes to PARP Inhibitor Resistance via Enhancing DNA Repair in BRCA2-/- Ovarian Cancer Cells

Poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) are approved to treat recurrent ovarian cancer with BRCA1 or BRCA2 mutations, and as maintenance therapy for recurrent platinum-sensitive ovarian cancer (BRCA wild-type or mutated) after treatment with platinum. However, the acquired resistance against PARPi remains a clinical hurdle. Here, we demonstrated that PARP inhibitor (olaparib)-resistant epithelial ovarian cancer (EOC) cells exhibited an elevated aldehyde dehydrogenase (ALDH) activity, mainly contributed by increased expression of ALDH1A1 due to olaparib-induced expression of BRD4, a member of bromodomain and extraterminal (BET) family protein. We also revealed that ALDH1A1 enhanced microhomology-mediated end joining (MMEJ) activity in EOC cells with inactivated BRCA2, a key protein that promotes homologous recombination (HR) by using an intrachromosomal MMEJ reporter. Moreover, NCT-501, an ALDH1A1-selective inhibitor, can synergize with olaparib in killing EOC cells carrying BRCA2 mutation in both in vitro cell culture and the in vivo xenograft animal model. Given that MMEJ activity has been reported to be responsible for PARPi resistance in HR-deficient cells, we conclude that ALDH1A1 contributes to the resistance to PARP inhibitors via enhancing MMEJ in BRCA2^-/- ovarian cancer cells. Our findings provide a novel mechanism underlying PARPi resistance in BRCA2-mutated EOC cells and suggest that inhibition of ALDH1A1 could be exploited for preventing and overcoming PARPi resistance in EOC patients carrying BRCA2 mutation.

Abstract 3691: XPC inhibits lung cancer cell dedifferentiation by suppressing Snail expression

Lung cancer remains a leading cause of cancer-related deaths in the United States with unfavorable prognosis mainly due to tumor relapse and metastasis, which are recently believed to be caused by a specific population of cancer cells within tumor termed “cancer stem cells (CSCs)”. These cells share the common characteristic of self-renewal and differentiation as normal stem cell, but also show resistance to chemotherapy and radiation therapy. Thus, targeting CSC populations in lung tumors is critical to the prevention of tumor metastasis. Xeroderma pigmentosum group C (XPC) was first recognized as a DNA repair protein. As a DNA repair factor, XPC plays an important role in preventing carcinogenesis. However, it has also been reported that XPC insufficiency is associated with poor treatment outcomes for a variety of cancers, and low expression of XPC is correlated with poor prognosis of lung cancer patients, suggesting that XPC may suppress lung cancer progression. Here, we show that downregulation of XPC expanded lung CSCs characterized by CD133+, while overexpression of XPC limited this cell population, as well as reduced the tumorigenic potential of the lung cancer cell line. Furthermore, we found that XPC knockdown is able to promote the CD133--to-CD133+ cell conversion in A549 cells, indicating that XPC can inhibit lung cancer cell dedifferentiation. Mechanistic investigation demonstrated that XPC can suppress Snail expression by directly binding to the promoter region of the SNAI1 gene, leading to the enrichment of histone H3 trimethylation at serine 27 (H3K27me3) and loss of histone H3 acetylation at serine 27 (H3K27Ac) in this region. Given that Snail plays a critical role in the induction of epithelial-mesenchymal transition (EMT), which is a major mechanism for the acquisition of stem cell-like properties, we believe that XPC can limit the CSC population by inhibiting cancer cell dedifferentiation. In summary, we conclude that low expression of XPC in lung tumors can de-repress the expression of Snail, promote EMT, and increase the de novo production of CSCs, eventually facilitating lung tumor progression.

Citation Format: Shurui Cai, Dayong Wu, Ananya Banerjee, Lu Liu, Chunhua Han, Tiantian Cui, Qi-En Wang. XPC inhibits lung cancer cell dedifferentiation by suppressing Snail expression [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 3691.