Cell Survival Assay Research Articles

LCP1 promotes ovarian cancer cell resistance to olaparib by activating the JAK2/STAT3 signalling pathway

ABSTRACT Background Resistance to poly (ADP-ribose) polymerase (PARP) inhibitors (PARPis) remain a major challenge in ovarian cancer (OC) treatment. However, the underlying mechanism of PARPi resistance is still poorly characterized. Increasing evidence has proven that lymphocyte cytosolic protein 1 (LCP1) promotes tumor progression. The JAK2/STAT3 signaling pathway plays an important role in increasing tumor metastatic ability and chemoresistance in cancer by promoting epithelial – mesenchymal transition (EMT). Methods We established an olaparib-resistant OC cell line and studied its toxicologic effects through cell survival, Transwell, colony formation, western blotting and flow cytometry assays. RNA sequencing and screening were then performed to identify genes associated with olaparib resistance. Lymphocyte cytosolic protein 1 (LCP1) was found to be overexpressed in olaparib-resistant OC cells. Results The inhibition of cell survival and promotion of cell apoptosis induced by olaparib in parental cells were significantly attenuated in olaparib-resistant cells. LCP1 was upregulated in olaparib-resistant cells compared with parental OC cells. Moreover, we found that the protein levels of JAK2/STAT3 signaling pathway components and EMT markers were increased in olaparib-resistant cells. Overexpression of LCP1 increased olaparib resistance in OC cells, and knockdown of LCP1 attenuated olaparib resistance. The changes in the protein levels of JAK2/STAT3 signaling pathway members and EMT markers between the cell types were similar to the changes in the levels of LCP1. Conclusions These findings indicate that LCP1 expression may play an important role in the resistance of OC to olaparib by activating the JAK2/STAT3 signaling pathway and EMT. LCP1 could be a potential therapeutic target for patients with OC who are resistant to olaparib. Our study provides a new mechanism of olaparib resistance.

ADAR1 enhances tumor proliferation and radioresistance in non-small cell lung cancer by interacting with Rad18.

Posttranslational modification significantly contributes to the transcriptional diversity of tumors. Adenosine deaminase acting on RNA 1 (ADAR1) and its mediated adenosine-to-inosine (A-to-I) editing have been reported to influence tumorigenesis across various cancer types. Nevertheless, the relationship between ADAR1 and radioresistence remains to be elucidated. The protein expression was detected by immunohistochemistry and Western Blot, while the mRNA expression was measured by RT-qPCR. The tumor growth was evaluated by CCK8, colony formation assays, EdU assay, and in-vivo mouse model. γ-H2AX foci formation, neutral comet tailing assay, and clonogenic cell survival assay were performed to determine the DNA damage and radiosensitivity. RNA-seq was conducted to identify the main downstream effector. The interaction between ADAR1 and Rad18 was examined by immunofluorescence and co-immunoprecipitation. We reported that ADAR1 was upregulated and correlated with poor prognosis in non-small cell lung cancer (NSCLC). In addition, we demonstrated that silencing ADAR1 significantly impaired tumor growth and improved tumor sensitivity to radiotherapy in vitro and in vivo. Mechanistically, we found that Rad18, which has been established as a versatile modulator of DNA repair, was the major downstream effector of ADAR1. ADAR1 not only regulated Rad18 mRNA expression by E2F3 but also colocalized and interacted with Rad18. Finally, our rescue experiments demonstrated that ADAR1's protumorigenic functions were partially dependent on Rad18. Our results revealed the role of ADAR1 in cooperation with Rad18 in modulating oncogenesis and radioresistance in NSCLC for the first time, and suggested the therapeutic potential of targeting ADAR1 in overcoming radioresistance.

CSIG-34. TYROSINE PHOSPHORYLATION OF NON-CANONICAL NF-ΚB P52 PROMOTES GLIOMA GROWTH AND CHEMORESISTANCE IN GBM

Abstract p52 is a nuclear factor-κB (NF-κB) transcription factor that comprises the non-canonical NF-κB pathway. The impact and mechanism of non-canonical NF-κB signaling remains understudied in glioblastoma (GBM). Subunit post-translational modification is a known mechanism of NF-κB activation, however phosphorylation of p52 has never been demonstrated. Elevated tyrosine kinase activity is a known-feature of GBM and portends worse survival. Further, p52 has been shown to upregulate factors that likely promote invasion of GBM, thereby reducing survival. Activation of p52 may serve as a link between increased kinase activity and poor survival in GBM. p52-knockout cell lines were generated using the CRISPR-Cas9 system and assessed for growth and survival differences in vitro and in syngeneic murine glioma models. Public glioma datasets and an institutional cohort were surveyed to corroborate p52-dependent survival differences in GBM. To determine whether p52 is post-translationally modified, we performed tandem mass spectrometry on p52 in GBM cells. Interacting factors were also analyzed and tested for site-specific modification of p52 via co-IP studies. We then generated PTM-null, knock-in glioma cell lines using CRISPR-CAS9 editing to demonstrate the functional significance of p52 PTMs, which were assessed using assays of relative cell growth, stemness, chemosensitivity and survival. Finally, we performed unbiased analysis of the p52 PTM-dependent transcriptome via RNA-seq. p52 loss significantly reduced glioma growth rate in vitro and improves murine survival. Retrospective analysis of GBM in patients suggests that p52 levels are negatively prognostic. Mass spectrometry identified multiple p52 PTMs with tyrosine phosphorylation sites as top hits. Identified phospho-tyrosine residues specifically interact with SRC-family kinases. PTM site editing significantly reduces glioma cell growth and stemness while enhancing chemosensitivity, reflecting broad transcriptome level changes. In sum, p52 activity enhances GBM growth and chemoresistance, which is partially modulated by tyrosine-specific phosphorylation. p52 warrants investigation as a therapeutic target in GBM, possibly in combination with kinase inhibitors and standard alkylating chemotherapy.

DNAR-03. ONCOMAGNETIC TREATMENT KILLS GLIOMA CELLS BY INHIBITING MITOCHONDRIAL ELECTRON TRANSPORT AND BY INDUCING OXIDATIVE STRESS AND DNA DAMAGE

Abstract A new noninvasive cancer therapeutic device developed in our laboratory called the Oncomagnetic device involves repeated stimulation with oscillating magnetic fields (sOMF) produced by spinning permanent magnets. It is technologically and mechanistically distinct from the Optune® device approved by the FDA and provides a novel approach for CNS tumor treatment. In 7 end-stage GBM patients, this device reversed the progression of recurrent tumors causing >30% reduction in their contrast-enhanced volumes within 4 – 8 weeks of treatment. Immune-competent mice with implanted mouse glioma cells in their brains also showed marked reduction in tumor size, increased survival (p< 0.05, n = 9) and greater DNA damage (γ-H2AX foci) in implanted tumor after sOMF treatment. Normal mice exposed to sOMF for 4 months had no adverse effects on the brain and other organs. In-vitro, sOMF inhibited mitochondrial ETC complex-I and markedly increased reactive oxygen species (ROS) levels in GBM cells. Detection of γ-H2AX and 53BP1 foci showed that sOMF caused significant DNA damage in GBM cells and diffuse intrinsic pontine glioma (DIPG) cells but not in normal astroglial SVGp12 cells. GBM cells exposed to sOMF for 4 h caused cell cycle arrest in the G1 phase and 30% - 40% loss of surviving colonies detected by clonogenic cell survival assay, while normal SVGp12 cells were not affected. This loss of survival in GBM cells was rescued by the antioxidant Trolox. These results indicate that sOMF stimulation has high anticancer potency comparable to low dose radiation therapy at the cellular level with an underlying mechanism of action that is substantially different from that proposed for Optune® TTF.

Picoplatin (II)-loaded chitosan nanocomposites as effective drug delivery systems: Preparation, mechanistic investigation of BSA/5-GMP/GSH binding and biological evaluations

The goal of the current study is to improve the characteristics and bioavailability of the drug picoplatin (PPt) by encapsulating it in chitosan nanoparticles (CS NPs) which allows for the targeted delivery of cytotoxic cargo to cancerous tissue, reducing toxic side effects and raising the therapeutic index. When picoplatin was delivered into the CS, it was able to produce a complex with CS (PPt@CS NPs) that had an appropriate particle size of 275 ± 10 nm, a reasonably low PDI of 0.15 ± 0.05, and high stability (ζ = −22.1 ± 0.3 mV). Since almost all pharmaceuticals work by binding to specific proteins or DNA, the in vitro binding mechanism and affinity of bovine serum albumin (BSA), low molecular building units of nucleic acids (5−GMP), and Glutathione (GSH) (considering that cisplatin resistance could be due to a reaction between cisplatin and GSH) to PPt and PPt@CS NPs were examined using stopped-flow and other spectroscopic approaches. Through two reversible processes, a rapid second-order binding followed by a slower first-order isomerization reaction, and a static quenching mechanism, PPt and PPt@CS NPs bind to BSA with relative reactivity of around (PPt)/(PPt@CS NPs) = 1/2.5. The 5−GMP interaction studies demonstrated that, in addition to changing the binding mechanism, PPt's encapsulation in CS increases its rate of reaction through coordination affinity. PPt interacted with 5-GMP via two reversible processes, a rapid second-order binding to phosphate followed by a slower first−order migration to the N7 of pyrimidine moiety. PPt@CS NPs showed weaker binding to GSH compared to PPt and hence PPt@CS NPs exhibits a lower resistance factor. It was also found that the in vitro drug release of PPt@CS NPs in PBS at pH 7.4 was steady, releasing 30 % of the PPt in just 5 h. Nonetheless, 75 % of the release in a pH 5.4 solution containing 10 mM GSH—a solution that mimics the tumor microenvironment—shows that the PPt@CS NPs system is sensitive to GSH and specifically targets malignant tissue. The encapsulation of PPt in CS complex maintained its anticancer activity, as shown by an in vitro cell-survival assay on HepG2 cancer cell lines and also cleavage efficiency toward the minor groove of pBR322 DNA via the hydrolytic way. These findings collectively suggested that inclusion PPt in CS would be an effective strategy to formulate a novel picoplatin formulation intended for use as targeted anticancer treatment.

A new cannabigerol derivative, LE-127/2, induces autophagy mediated cell death in human cutaneous melanoma cells

Despite the targeted- and immunotherapies used in the past decade, survival rate among patients with metastatic melanoma remains low, therefore, melanoma is responsible for the majority of skin cancer-related deaths. The ongoing investigation of natural antitumor agents, the nonpsychoactive cannabinoid, cannabigerol (CBG) found in Cannabis sativa is emerging as a promising candidate. CBG offers a potential therapeutic role in the treatment of melanoma demonstrating cell growth inhibition in some tumors. Its low water solubility and bioavailability hinder the potential effectiveness. To address these challenges, a modified CBG, namely LE-127/2 was synthesized by Mannich-type reaction. The aim was to investigate the effect of this novel compound on cell proliferation as well as the mechanism of cell death with a particular focus on autophagy and apoptosis. Human cutan melanoma cell lines, WM35, A2058 and WM3000 were utilized for the present study. Cell proliferation of the cells after the treatment with LE-127/2, parent CBG or vemurafenib was assessed by Cell Titer Blue Assay. Cells were treated with a 1.25–80 µM of the above-mentioned compounds, and it was found that at 20 μM of all drugs showed a comparable effective inhibition of cell proliferation, however, vemurafenib and CBG proved to be more effective than LE-127/2. In addition, clonogenic cell survival assays were performed to examine the inhibitory effect of LE-127/2 on the colony formation ability of melanoma cell lines. Cells treated with 20 µM of LE-127/2 for 14 days showed about a 50% suppression of clonogenic cell survival. LE-127/2 exerted the most intensive inhibition on A2058 cell colonies. Furthermore, notably, LDH cytotoxicity assay performed on HaCaT cell line, proved LE-127/2 to be cytotoxic only at higher concentration, such as 80 μM, while the parent CBG was cytotoxic at concentration as low as 5 μM, suggesting that the new CBG derivative as a drug candidate may be applied in human pharmacotherapy without causing a substantial damage in intact epidermal cells. Analysis of protein expression revealed the impact of LE-127/2 on the expression of basic proteins (LC-3, Beclin-1 and p62) involved in the process of autophagy in the three different melanoma cell lines studied. Elevated expression of these proteins was detected as a result of LE-127/2 (20 µM) treatment. LE-127/2 also induced the expression of some proteins involved in apoptosis, and it is particularly noteworthy the increased level of cleaved PARP. Based on the results obtained, it can be concluded that LE-127/2 induced autophagy could lead to the inhibition of cell proliferation and death in melanoma cells.

Combining Mitomycin C with inhibition of BAD phosphorylation enhances apoptotic cell death in advanced cervical cancer

ObjectiveMitomycin C (MMC), a DNA-damaging chemotherapeutic, is commonly used clinically for recurrent cervical carcinoma (CC), either alone or in combination. MMC generates DNA damage resulting in CC cell death yet also induces increased AKT-BAD phosphorylation associated with drug resistance and reduced clinical benefit. The present study evaluates the efficacy of combined MMC and a BAD phosphorylation inhibitor in CC. MethodsThe association and function of phosphorylation of BAD on serine 99 (pBADS99) for cell survival of both MMC-resistant or sensitive-CC cells was explored. BAD was mutated to BADS99A to examine the requirement of BADS99 for CC cell survival and a novel small-molecule inhibitor of pBADS99 was utilized. Cell proliferation, survival, foci formation, and patient-derived organoids (PDOs) assays were utilized to determine efficacy, synergy and related mechanisms. ResultsMMC IC50 was positively correlated to the cell line pBADS99/BAD ratio. Increased BADS99 phosphorylation was observed in both MMC-sensitive or -resistant CC cells after MMC treatment. Inhibition of pBADS99 in CC cell lines produced synergistic apoptosis through BAD-mediated apoptotic pathways and enhanced DNA damage in response to MMC. The concurrent use of pharmacological inhibition of pBADS99 and MMC was synergistic, resulting in diminished cell viability and inducing apoptotic cell death in MMC-sensitive and -resistant CC cell lines or patient-derived organoids. ConclusionA combination of MMC with inhibition of BAD phosphorylation potentiated efficacy compared to single agent treatment. The potential further development of such strategies may provide outcome benefits to patients with CC.

Improvement of Echinacea purpurea and Ganoderma lucidum Extracts with Cell Model on Influenza A/B Infection.

Since 2019, COVID-19 has been raging around the world. Respiratory viral infectious diseases such as influenza and respiratory syncytial virus (RSV) infection are also prevalent, with influenza having the ability to cause seasonal pandemics. While vaccines and antiviral drugs are available to prevent and treat disease, herbal extracts would be another option. This study investigated the inhibitory effects of extracts of Echinacea purpurea (EP) and Ganoderma lucidum (G. lucidum) and the advanced G. lucidum drink (AG) on influenza A/B viruses. To determine whether EP and G. lucidum extracts enhance cell immunity and thus prevent virus infection or act to directly suppress viruses, cell survival and hemagglutination (HA) assays were used in this study. Cells were treated with samples at different concentrations (each sample concentration was tested from the highest non-cytotoxic concentration) and incubated with influenza A/B for 24 h, with the results showing that both G. lucidum and EP extracts and mixtures exhibited the ability to enhance cell survival against viruses. In the HA assay, AG and EP extract showed good inhibitory effect on influenza A/B viruses. All of the samples demonstrated an improvement of the mitochondrial membrane potential and improved resistance to influenza A/B virus infection. EP and G. lucidum extracts at noncytotoxic concentrations increased cell viability, but only AG and EP extract directly decreased influenza virus titers. In conclusion, results indicate the ability of EP and G. lucidum extract to prevent viruses from entering cells by improving cell viability and mitochondrial dysfunction and EP extract showed direct inhibition on viruses and prevented viral infection at post-infection strategy.

A network-based trans-omics approach for predicting synergistic drug combinations

BackgroundCombination therapy can offer greater efficacy on medical treatments. However, the discovery of synergistic drug combinations is challenging. We propose a novel computational method, SyndrumNET, to predict synergistic drug combinations by network propagation with trans-omics analyses.MethodsThe prediction is based on the topological relationship, network-based proximity, and transcriptional correlation between diseases and drugs. SyndrumNET was applied to analyzing six diseases including asthma, diabetes, hypertension, colorectal cancer, acute myeloid leukemia (AML), and chronic myeloid leukemia (CML).ResultsHere we show that SyndrumNET outperforms the previous methods in terms of high accuracy. We perform in vitro cell survival assays to validate our prediction for CML. Of the top 17 predicted drug pairs, 14 drug pairs successfully exhibits synergistic anticancer effects. Our mode-of-action analysis also reveals that the drug synergy of the top predicted combination of capsaicin and mitoxantrone is due to the complementary regulation of 12 pathways, including the Rap1 signaling pathway.ConclusionsThe proposed method is expected to be useful for discovering synergistic drug combinations for various complex diseases.

MARCH1 negatively regulates TBK1-mTOR signaling pathway by ubiquitinating TBK1

BackgroundTBK1 positively regulates the growth factor-mediated mTOR signaling pathway by phosphorylating mTOR. However, it remains unclear how the TBK1-mTOR signaling pathway is regulated. Considering that STING not only interacts with TBK1 but also with MARCH1, we speculated that MARCH1 might regulate the mTOR signaling pathway by targeting TBK1. The aim of this study was to determine whether MARCH1 regulates the mTOR signaling pathway by targeting TBK1.MethodsThe co-immunoprecipitation (Co-IP) assay was used to verify the interaction between MARCH1 with STING or TBK1. The ubiquitination of STING or TBK1 was analyzed using denatured co-immunoprecipitation. The level of proteins detected in the co-immunoprecipitation or denatured co-immunoprecipitation samples were determined by Western blotting. Stable knocked-down cells were constructed by infecting lentivirus bearing the related shRNA sequences. Scratch wound healing and clonogenic cell survival assays were used to detect the migration and proliferation of breast cancer cells.ResultsWe showed that MARCH1 played an important role in growth factor-induced the TBK1- mTOR signaling pathway. MARCH1 overexpression attenuated the growth factor-induced activation of mTOR signaling pathway, whereas its deficiency resulted in the opposite effect. Mechanistically, MARCH1 interacted with and promoted the K63-linked ubiquitination of TBK1. This ubiquitination of TBK1 then attenuated its interaction with mTOR, thereby inhibiting the growth factor-induced mTOR signaling pathway. Importantly, faster proliferation induced by MARCH1 deficiency was weakened by mTOR, STING, or TBK1 inhibition.ConclusionMARCH1 suppressed growth factors mediated the mTOR signaling pathway by targeting the STING-TBK1-mTOR axis.

Ectopic Activation of Fgf8 in Dental Mesenchyme Causes Incisor Agenesis and Molar Microdontia.

Putatively, tooth agenesis was attributed to the initiation failure of tooth germs, though little is known about the histological and molecular alterations. To address if constitutively active FGF signaling is associated with tooth agenesis, we activated Fgf8 in dental mesenchyme with Osr-cre knock-in allele in mice (Osr2-creKI; Rosa26R-Fgf8) and found incisor agenesis and molar microdontia. The cell survival assay showed tremendous apoptosis in both the Osr2-creKI; Rosa26R-Fgf8 incisor epithelium and mesenchyme, which initiated incisor regression from cap stage. In situ hybridization displayed vanished Shh transcription, and immunostaining exhibited reduced Runx2 expression and enlarged mesenchymal Lef1 domain in Osr2-creKI; Rosa26R-Fgf8 incisors, both of which were suggested to enhance apoptosis. In contrast, Osr2-creKI; Rosa26R-Fgf8 molar germs displayed mildly suppressed Shh transcription, and the increased expression of Ectodin, Runx2 and Lef1. Although mildly smaller than WT controls prenatally, the Osr2-creKI; Rosa26R-Fgf8 molar germs produced a miniature tooth with impaired mineralization after a 6-week sub-renal culture. Intriguingly, the implanted Osr2-creKI; Rosa26R-Fgf8 molar germs exhibited delayed odontoblast differentiation and accelerated ameloblast maturation. Collectively, the ectopically activated Fgf8 in dental mesenchyme caused incisor agenesis by triggering incisor regression and postnatal molar microdontia. Our findings reported tooth agenesis resulting from the regression from the early bell stage and implicated a correlation between tooth agenesis and microdontia.

FLASH Effect Is Not Always Induced by Ultra-high Dose-rate Proton Irradiation Under Hypoxic Conditions.

Pre-clinical studies have shown that irradiation with electrons at an ultra-high dose-rate (FLASH) spares normal tissue while maintaining tumor control. However, most in vitro experiments with protons have been conducted using a non-clinical irradiation system in normoxia alone. This study evaluated the biological response of non-tumor and tumor cells at different oxygen concentrations irradiated with ultra-high dose-rate protons using a clinical system and compared it with the conventional dose rate (CONV). Non-tumor cells (V79) and tumor cells (U-251 and A549) were irradiated with 230 MeV protons at a dose rate of >50 Gy/s or 0.1 Gy/s under normoxic or hypoxic (<2%) conditions. The surviving fraction was analyzed using a clonogenic cell survival assay. No significant difference in the survival of non-tumor or tumor cells irradiated with FLASH was observed under normoxia or hypoxia compared to the CONV. Proton irradiation at a dose rate above 40 Gy/s, the FLASH dose rate, did not induce a sparing effect on either non-tumor or tumor cells under the conditions examined. Further studies are required on the influence of various factors on cell survival after FLASH irradiation.

Preparation of interleukin-1β-targeted nanobodies and their effects on apoptosis in hypoxic cardiomyocytes of mice

Objective: To prepare interleukin-1β-targeted nanoantibodies and observe their effects on apoptosis in hypoxic cardiomyocyte of mice. Methods: Using DNA recombination technology, the pET-16b and pHEN1 expression vectors were used to construct the prokaryotic expression plasmids of interleukin-1β-targeted nanobodies (pET-16b-4G6M-VHH, pET-16b-5BVP-VHH, pET-16b-5MVZ-VHH, pHEN1-4G6M-VHH, pHEN1-5BVP-VHH and pHEN1-5MVZ-VHH, where VHH is a variable domain of heavy chain antibody, 4G6M-VHH, 5BVP-VHH, 5MVZ-VHH were three interleukin-1β-targeted nanoantibodies respectively). The constructed plasmids were transferred into Escherichia coli Rosetta2 (DE3) for induction of expression and nickel column purification, respectively. The sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting were employed to identify the expression product and purified product, and the enzyme-linked immune sorbent assay (ELISA) was performed to determine their affinity. The cardiomyocyte hypoxia model was used with the highest affinity IL-1β-targeted nanobody (pHEN1-5MVZ-VHH), and cell survival and apoptosis rates were detected (the experiment was divided into normal control group, hypoxia model group, blank plasmid group and 12.5, 25.0, 50.0 μg/ml pHEN1-5MVZ-VHH treatment groups). Results: SDS-PAGE and Western blotting results showed that the anti-interleukin-1β (IL-1β) nanobodies with a relative molecular mass of about 15 000 were successfully obtained. Likewise, ELISA results found that the nanobodies expressed in pHEN1 vector group had higher affinity for IL-1β antigen compared with pET-16b vector group (4G6M-VHH group: 3.20±0.03 vs 1.20±0.03, P<0.001; 5BVP-VHH group: 3.18±0.06 vs 1.21±0.02, P<0.001; 5MVZ-VHH group: 3.38±0.05 vs 1.62±0.04, P<0.001). Additionally, the results of cell survival assay and apoptosis assay detected that compared with the hypoxia model group, HL-1 cell activity was significantly increased in the 25.0 μg/ml and 50.0 μg/ml pHEN1-5MVZ-VHH treatment groups [(75.55±2.23)% vs (46.90±2.51)%, P<0.001; (74.36±1.96)% vs (46.90±2.51)%, P<0.001], and apoptosis rate was significantly reduced [(6.83±0.27)% vs (10.24±0.76)%, P<0.001; (6.68±0.38)% vs (10.24±0.76)%, P<0.001]. Conclusions: 4G6M-VHH, 5BVP-VHH, and 5MVZ-VHH are expressed by both pET-16b and pHEN1 expression vectors and the nanobodies produced by the pHEN1 vector display enhanced antigen affinity. Furthermore, in hypoxic cardiomyocytes, pHEN1-5MVZ-VHH treatment reduces cell apoptosis.

Characterization of MET Alterations in 37 Gastroesophageal Cancer Cell Lines for MET-Targeted Therapy.

Capmatinib and savolitinib, selective MET inhibitors, are widely used to treat various MET-positive cancers. In this study, we aimed to determine the effects of these inhibitors on MET-amplified gastric cancer (GC) cells. Methods: After screening 37 GC cell lines, the following cell lines were found to be MET-positive with copy number variation >10: SNU-620, ESO51, MKN-45, SNU-5, and OE33 cell lines. Next, we assessed the cytotoxic response of these cell lines to capmatinib or savolitinib alone using cell counting kit-8 and clonogenic cell survival assays. Western blotting was performed to assess the effects of capmatinib and savolitinib on the MET signaling pathway. Xenograft studies were performed to evaluate the in vivo therapeutic efficacy of savolitinib in MKN-45 cells. Savolitinib and capmatinib exerted anti-proliferative effects on MET-amplified GC cell lines in a dose-dependent manner. Savolitinib inhibited the phosphorylation of MET and downstream signaling pathways, such as the protein kinase B (AKT) and extracellular signal-regulated kinase (ERK) pathways, in MET-amplified GC cells. Additionally, savolitinib significantly decreased the number of colonies formed on the soft agar and exerted dose-dependent anti-tumor effects in an MKN-45 GC cell xenograft model. Furthermore, a combination of trastuzumab and capmatinib exhibited enhanced inhibition of AKT and ERK activation in human epidermal growth factor receptor-2 (HER2)- and MET-positive OE33 cells. Targeting MET with savolitinib and capmatinib efficiently suppressed the growth of MET-amplified GC cells. Moreover, these MET inhibitors exerted synergistic effects with trastuzumab on HER2- and MET-amplified GC cells.

In vitro study on anti-proliferative and anti-cancer activity of picrosides in triple-negative breast cancer.

Picrorhiza kurroa, an "Indian gentian," a known Himalayan medicinal herb with rich source of phytochemicals like picrosides I, II, and other glycosides, has been traditionally used for the treatment of liver and respiratory ailments. Picrosides anti-proliferative, anti-oxidant, anti-inflammatory and other pharmacological properties were evaluated in treating triple-negative breast cancer (TNBC). Picroside I and II were procured from Sigma-Aldrich and were analyzed for anti-cancer activity in triple-negative breast cancer (MDA-MB-231) cells. Cell viability was analyzed using MTT and trypan blue assays. Apoptosis was analyzed through DNA fragmentation and Annexin V/PI flow cytometric analysis. Wound healing and cell survival assays were employed to determine the inhibition of invasion capacity and anti-proliferative activity of picrosides in MDA-MB-231 cells. Measurement of intracellular ROS was studied through mitochondrial membrane potential assessment using DiOC6 staining for anti-oxidant activity of picrosides in MDA-MB-231 cells. Both Picroside I and II have shown decreased cell viability of MDA-MB-231 cells with increasing concentrations. IC50 values of 95.3µM and 130.8µM have been obtained for Picroside I and II in MDA-MB-231 cells. Early apoptotic phase have shown an increase of 20% (p < 0.05) with increasing concentrations (0, 50, 75, and 100µM) of Picroside I and 15% (p < 0.05) increase with Picroside II. Decrease in mitochondrial membrane potential of 2-2.5-fold (p < 0.05) was observed which indicated decreased reactive oxygen species (ROS) generation with increasing concentrations of Picroside I and II. An increasing percentage of 70-80% (p < 0.05) cell population was arrested in G0/G1 phase of cell cycle after Picroside I and II treatment in cancer cells. Our results suggest that Picroside I and II possess significant anti-proliferative and anti-cancer activity which is mediated by inhibition of cell growth, decreased mitochondrial membrane potential, DNA damage, apoptosis, and cell cycle arrest. Therefore, Picroside I and II can be developed as a potential anti-cancer drug of future and further mechanistic studies are underway to identify the mechanism of anti-cancer potential.

Abstract PO3-24-06: Integrative genomic and CRISPR screen analysis identifies synthetic viability interactions in BRCA1/2 cancers

Abstract Background Pathogenic BRCA1 and BRCA2 (BRCA1/2) germline mutations contribute to hereditary breast cancer and are linked with increased risk of other cancers. Paradoxically, bi-allelic inactivation of BRCA1/2 (bBRCA1/2) is embryonically lethal. Although TP53 loss can at least in part mitigated the deleterious impact of Brca1 deficiency in mice, this is insufficient in human cells to compensate for decreased proliferative capacity. What other compensatory mechanisms facilitate oncogenesis remains unclear. Methods We performed an integrative analysis of cancer genomes from bBRCA1/2 tumors and CRISPR/Cas9 screens from cellular models to identify novel gene candidates that facilitate synthetic viability. First, we analyzed cancer genomes from ovarian and breast cancer derived from TCGA and identified genomic loci, which were enriched for recurrent copy number alterations (CNAs) in bBRCA1/2 tumors. We subsequently identified genes from these CNA loci that had corresponding changes in gene expression. Then, we used high-throughput genome-wide CRISPR/Cas9 knockout screens in BRCA1/2−/− cell lines (BRCA1−/- in RPE1 cells, BRCA2−/− in DLD1 cells) to identify which of these genes increased cell proliferation in vitro. Lastly, we experimentally validated these synthetic viable interactions using an orthogonal MCF12a system to evaluate changes in colony formation with a clonogenic cell survival assay. Results In human cancer genomes, we identified that bBRCA1/2 tumors harbored recurrent large-scale genetic deletions significantly more frequent than histologically matched control tumors. We identified 148 cytobands (23 distinct genomic loci) frequently deleted in bBRCA1/2 ovarian cancers (N=92), and 90 cytobands (15 distinct genomic loci) in bBRCA1/2 ER+ breast cancers (N=30). Subsequent computational analysis of gene expression data identified transcriptionally decreased genes in the frequently deleted loci. Cross-referencing with CRISPR/Cas9 screens in BRCA1/2−/− cells, we ultimately identified 277 and 218 genes that were altered in human tumors and putatively enhanced viability in BRCA1/2-null models but not in isogenic wild-type cell lines in BRCA1 and BRCA2 models, respectively. We subsequently selected 17 genes that either increased viability in BRCA1, BRCA2, or both contexts for experimental validation. Of these, about 40% (7 of 17) were experimentally validated (RIC8A, GNA12, ATMIN, IPO7, ATXN2, KDM1A, and NUP98) and had evidence of synthetic viability in this cellular context. Interestingly, RIC8A and GNA12 interact with each other, are both involved in G protein-coupled signaling pathway, and are synthetically viable with both BRCA1−/− and BRCA2−/− cells. In a re-analysis of a recently published genomic dataset on metastatic breast cancer, we found that homologous recombination deficient tumors developed additional loss of function mutations in RIC8A in the metastatic setting. Conclusions This study provides insights into the oncogenesis of BRCA1/2 malignancies and describes a high-throughput framework to identify synthetic viability interactions and causal driver genes affected by large-scale CNAs in human cancers. Citation Format: Yingjie Zhu, Xin Pei, Ardijana Novaj, Jeremy Setton, Fatemeh Derakhshan, Pier Selenica, Niamh McDermott, Sonali Sinha, Atif Khan, Simon Powell, Jorge Reis-Filho, Nadeem Riaz. Integrative genomic and CRISPR screen analysis identifies synthetic viability interactions in BRCA1/2 cancers [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-24-06.

NIO-1, A Novel Inhibitor of OCT1, Enhances the Antitumor Action of Radiofrequency Ablation against Hepatocellular Carcinoma.

Radiofrequency ablation (RFA) is an important treatment strategy for patients with advanced hepatocellular carcinoma (HCC). However, its therapeutic effect is unsatisfactory and recurrence often occurs after RFA treatment. The octamer-binding transcription factor OCT1 is a novel tumour-promoting factor and an ideal target for HCC therapy. This study aimed to expand the understanding of HCC regulation by OCT1. The expression levels of the target genes were examined using qPCR. The inhibitory effects of a novel inhibitor of OCT1 (NIO-1) on HCC cells and OCT1 activation were examined using Chromatin immunoprecipitation or cell survival assays. RFA was performed in a subcutaneous tumour model of nude mice. Patients with high OCT1 expression in the tumour tissue had a poor prognosis after RFA treatment (n = 81). The NIO-1 showed antitumor activity against HCC cells and downregulated the expression of the downstream genes of OCT1 in HCC cells, including those associated with cell proliferation (matrix metalloproteinase-3) and epithelial-mesenchymal transition-related factors (Snail, Twist, N-cadherin, and vimentin). In a subcutaneous murine model of HCC, NIO-1 enhanced the effect of RFA treatment on HCC tissues (n = 8 for NIO-1 and n = 10 for NIO-1 + RFA). This study demonstrated the clinical importance of OCT1 expression in HCC for the first time. Our findings also revealed that NIO-1 aids RFA therapy by targeting OCT1.

In vitro examination of the antioxidants, osajin and pomiferin, in cultured rat mesangial cells

Purpose: The goal of this study was to identify concentrations of osajin and pomiferin, purified compounds originating from Maclura pomifera, that work as effective antioxidants while maintaining cell viability in cultured rat mesangial cells. Rationale and Significance: Diabetic nephropathy (DN) is a serious complication faced by type 1 and type 2 diabetic patients alike. Oxidative stress has emerged as an important pathogenic mechanism in the development of glomerular and tubular injury in DN. Identifying novel antioxidants found in natural compounds could serve as an effective treatment in DN to prevent renal cell damage. Methodology: Rat mesangial cells (NMS) were grown to confluency in RPMI 1640 medium with 17% fetal bovine serum and 1x antibiotic/antimycotic. NMS cells were exposed to vehicle (control) or varying concentrations of pomiferin or osajin. MTT cell survival assays were used to assess cell viability for the selected concentrations. Antioxidant status was assessed using the Total Antioxidant Capacity Assay from Sigma-Aldrich and quercetin was selected as a positive control. Findings: Data from MTT cell viability assays demonstrated several concentrations (25, 50, and 100 mM) of both osajin and pomiferin maintained cell viability in NMS cells. Antioxidant capacity assay plans will be discussed as this is an ongoing project and we hope to identify the total antioxidant capacity and antioxidant response in NMS cells. Future plans also include moving forward with selected concentrations to identify the effectiveness of osajin and/or pomiferin in preventing high glucose-induced damage to glomerular cells and proximal tubular epithelial cells as this will be essential for investigating the benefit of using either compound in diabetic nephropathy. Research reported in this poster was supported by the University of the Incarnate Word Offce of Research and Graduate Studies. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The Role of SARS-CoV-2 Spike Protein in the Growth of Cervical Cancer Cells.

Recently developed vaccines for the SARS-CoV-2 virus utilize endogenous production of the virus' spike protein (SP), allowing the host to develop an immune response. As a result of the novelty of this virus and its vaccines, little is known overall about the potential effects of the SP on the pathogenesis of neoplasia, either from vaccination or from infection. This study was designed to investigate whether SARS-CoV-2 SP has any direct effect on SiHa cervical cancer cells. The effects of SARS-CoV-2 SP on cervical cancer cell proliferation and apoptosis were investigated by using clonogenic cell survival assay, quick cell proliferation assay, and caspase-3 activity kits in a widely-used cervical cancer cell line, SiHa. RT-PCR and immunohistochemistry were also performed to determine the potential molecular mechanisms. The growth and proliferation of SiHa cancer cells were inhibited by SARS-CoV-2 SP. SARS-CoV-2 SP also induced apoptosis in SiHa cancer cells. The anti-proliferative effect of SARS-CoV-2 SP on SiHa cancer cells was associated with the up-regulation of the anti-proliferative molecule p53. The pro-apoptotic effect of SARS-CoV-2 SP on SiHa cells was associated with the up-regulation of the pro-apoptotic molecule TRAIL. SARS-CoV-2 SP inhibits the growth of cervical cancer via up-regulation of p53 and TRAIL. Further studies are needed to elaborate on the potential effects of the SARS-CoV-2 SP on other cancer cell lines and normal physiological cell lines for comparison.

Ameliorative Effect of Natural Sesquiterpene Alcohol Cedrol Against Cerebral Ischemia Infarction-In Vitro and In Vivo Studies.

Cedrol is a major bioactive compound present in the Cedrus atlantica with numerous biological properties. In this study, we elucidated the neuroprotective properties of cedrol against ischemic infarction in animal and in vitro studies. A cerebral ischemic/reperfusion model was induced in adult Wistar rats, and oxygen-glucose deprivation/reperfusion was induced in SH-SY5Y neuronal cells and treated with different concentrations of cedrol. The percentage of water content, cerebral infarct, and neurological deficit score was assessed in experimental rats. The acetylcholinesterase activity and inflammatory cytokines were quantified to analyze the anti-inflammatory potency of cedrol. Oxidative stress marker malondialdehyde and antioxidants were quantified to evaluate the antioxidant potency of cedrol in an ischemic condition. The neuroprotective potency of cedrol was confirmed by histopathological analysis of the brain tissue of cedrol-treated I/R-induced rats. In in vitro studies, the MTT and LDH assays were performed in cedrol-treated OGD/R SH-SY5Y cells to analyze the cytoprotective effect of cedrol. The anti-inflammatory property of cedrol was confirmed by quantifying the pro-inflammatory cytokine levels in OGD/R-induced cedrol-treated SH-SY5Y cells. The results obtained prove that cedrol significantly prevents brain edema, neurological deficits, acetylcholinesterase activity, and oxidative damage in ischemic-induced rats. It inhibited neuroinflammation in ischemic-induced rats and also in in vitro models. The neuroprotective effect of cedrol during an ischemic condition was authentically established with histological analysis in an animal model and cell survival assays in an in vitro model. Overall, our results confirm that cedrol is a potent alternative drug to treat cerebral ischemia in the future.