Tumor Cell Lines Research Articles

229 (PB217): Evaluation of the combined antiproliferative effects of Pan-RAF Inhibitor AZ-628 and MEK1 Inhibitor AZD-6244 across a diverse range of tumor cell lines

229 (PB217): Evaluation of the combined antiproliferative effects of Pan-RAF Inhibitor AZ-628 and MEK1 Inhibitor AZD-6244 across a diverse range of tumor cell lines

Combination screen in multi-cell type tumor spheroids reveals interaction between aryl hydrocarbon receptor antagonists and E1 ubiquitin-activating enzyme inhibitor

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that regulates genes of drug transporters and metabolic enzymes to detoxify small molecule xenobiotics. It has a complex role in cancer biology, influencing both the progression and suppression of tumors by modulating malignant properties of tumor cells and anti-tumor immunity, depending on the specific tumor type and developmental stage. This has led to the discovery and development of selective AhR modulators, including BAY 2416964 which is currently in clinical trials. To identify small molecule anticancer agents that might be combined with AhR antagonists for cancer therapy, a high-throughput combination screen was performed using multi-cell type tumor spheroids grown from malignant cells, endothelial cells, and mesenchymal stem cells. The AhR selective antagonists BAY 2416964, GNF351, and CH-223191 were tested individually and in combination with twenty-five small molecule anticancer agents. As single agents, BAY 2416964 and CH-223191 showed minimal activity, whereas GNF351 reduced the viability of some spheroid models at concentrations greater than 1 µM. The activity of most combinations aligned well with the single agent activity of the combined agent, without apparent contributions from the AhR antagonist. All three AhR antagonists sensitized tumor spheroids to TAK-243, an E1 ubiquitin-activating enzyme inhibitor. These combinations were active in spheroids containing bladder, breast, ovary, kidney, pancreas, colon, and lung tumor cell lines. The AhR antagonists also potentiated pevonedistat, a selective inhibitor of the NEDD8-activating enzyme E1 regulatory subunit, in several tumor spheroid models. In contrast, the AhR antagonists did not enhance the cytotoxicity of the proteasome inhibitor bortezomib.

Remembering Hypoxia: Uncovering the Long-Term Effects of Transient Oxygen Deprivation on IFN Signaling and Progression of Breast Cancer.

Hypoxia occurs in 90% of solid tumors and is strongly associated with an increased propensity for metastasis. Hypoxia induces tumor progression largely through inducing HIF-mediated transcription, resulting in alterations to tumor cell metabolism, as well as increases in migration and invasion. Hypoxia also results in a myriad of changes to the tumor microenvironment (TME). While many studies have examined the immediate effects of hypoxia on tumor cells and the associated TME, far fewer have focused on the long-term consequences of transient reductions in oxygen. In this issue of Cancer Research, Iriondo and colleagues examined whether short-term exposure to hypoxia leads to a "hypoxic memory" in the context of breast cancer. The authors used established cell lines and circulating tumor cell lines to demonstrate that these cells harbor a hypoxic memory that sustains downregulation of IFN signaling and antigen presentation (AP) pathways that contribute to tumor progression via alterations to tumor cells and the TME. The authors further showed that cells that have experienced hypoxia maintain the reduction in IFN signaling in vivo and are more aggressive. They determined that the hypoxic memory and reduction of IFN signaling can be reversed with a histone deacetylase inhibitor, entinostat, providing a potential means to reverse hypoxia-induced suppression of IFN signaling. As suppression of IFN signaling has the potential to influence both tumor cells and the TME, the identification of a strategy to inhibit long-term suppression of IFN signaling downstream of hypoxia could prove to be an effective means to target tumor progression. See related article by Iriondo et al., p. 3141.

Zirconium- 89 Labeled Antibody K1-70 for PET Imaging of Thyroid-stimulating Hormone Receptor Expression in Thyroid Cancer.

Thyroid-stimulating hormone receptor (TSHR) is a G-protein coupled receptor that is highly expressed on benign and malignant thyroid tissues. TSHR binding and activation has long been a component of thyroid cancer molecular imaging and radiotherapy, by promoting expression of the sodium-iodide symporter (NIS) and incorporation of I-131 into thyroid hormones. Here, we report the radiosynthesis and preclinical evaluation of a Zirconium-89 (89Zr) labeled TSHR antibody to serve as a positron emission tomography (PET) diagnostic correlate for therapeutic agents targeting TSHR without reliance on NIS. TSHR human monoclonal antibody K1-70 was conjugated to chelator desferrioxamine-p-benzyl-isothiocyanate, followed by labeling with Zr-89, yielding the radiotracer 89Zr-DFO-TSHR-Ab. The in vitro cellar uptake and binding affinity of 89Zr-DFO-TSHR-Ab were analyzed in three new TSHR stable overexpressing tumor cell lines and their corresponding wild types (WT) with low or no TSHR expression. 89Zr-DFO-TSHR-Ab PET/CT imaging of TSHR expression was evaluated in tumor mouse models bearing one TSHR-positive tumor and other negative control with or without the coinjection of antibody K1-70, and then verified by radiotracer biodistribution study and tumor immunohistochemistry (IHC). The conjugate DFO-TSHR-Ab was labeled with Zr-89 at 37°C for 60min and purified by PD-10 column in radiochemical yields of 68.8 ± 9.9%, radiochemical purities of 98.7 ± 0.8%, and specific activities of 19.1 ± 2.7mCi/mg (n = 5). In vitro cell studies showed 89Zr-DFO-TSHR-Ab had significantly high uptake on TSHR expressing tumor cells with nanomolar affinity and high potency. Preclinical PET/CT imaging revealed that 89Zr-DFO-TSHR-Ab selectively detected TSHR expressing thyroid tumors and displayed improved in vivo performance with the coinjection of unlabeled TSHR antibody K1-70 leading to higher uptake in TSHR expressing tumors than parental WT tumors and physiologic tissues; this observation was confirmed by the biodistribution and immunostaining analyses. We synthesized 89Zr-labeled antibody K1-70 as a new radiopharmaceutical for PET imaging of TSHR. 89Zr-DFO-TSHR-Ab has high radioactive uptake and retention in TSHR expressing tumors and cleared quickly from most background tissues in mouse models. Our study demonstrated that 89Zr-DFO-TSHR-Ab has the potential for PET imaging of TSHR-positive thyroid cancer and monitoring TSHR-targeted therapy.

Quinoline- rhenium(I) tricarbonyl complexes: synthesis, spectral characterization and antiproliferative activity on T-cell lymphoma

Novel 6-substituted 2-(trifluoromethyl)quinoline 5a-5e and coumarin 6a-6d ligands with aldoxime ether linked pyridine moiety were synthesized by O-alkylation of quinoline and coumarin with (E)-picolinaldehyde oxime and subsequently with [Re(CO)5Cl] gave rhenium(I) tricarbonyl complexes 5aRe–5eRe and 6aRe–6dRe that were fully characterized by NMR, single-crystal X-ray diffraction, IR and UV–Vis spectroscopy. The results of antiproliferative evaluation of quinoline and coumarin ligands and their rhenium(I) tricarbonyl complexes on various human tumor cell lines, including acute lymphoblastic leukemia (CCRF-CEM), acute monocytic leukemia (THP1), cervical adenocarcinoma (HeLa), colon adenocarcinoma (CaCo-2), T-cell lymphoma (HuT78), and non-tumor human fibroblasts (BJ) showed that the quinoline complexes 5aRe–5eRe had higher inhibitory activity than coumarin complexes 6aRe–6dRe, particularly against T-cell lymphoma (HuT78) cells. 6-Methoxy-2-(trifluoromethyl)quinoline 5e and 6-methylcoumarin 6d, and their rhenium(I) tricarbonyl complexes 5eRe and 6dRe were found to arrest the cell cycle of HuT78 cells by causing a significant accumulation of cells in the G0/G1 phase and a marked decrease in the number of cells in the G2/M phase. These rhenium(I) tricarbonyl complexes also slightly increased ROS production and significantly decreased the mitochondrial membrane potential by 50 % (5eRe) and 45 % (6dRe) compared to untreated cells and cells treated with 5e and 6d. These results suggest that the cytotoxic effects of these compounds are mediated by their effects on mitochondrial membrane potential and the subsequent increase in ROS production.

Hypoxic Memory Mediates Prolonged Tumor-Intrinsic Type I Interferon Suppression to Promote Breast Cancer Progression.

Hypoxia is a common feature of many solid tumors due to aberrant proliferation and angiogenesis that is associated with tumor progression and metastasis. Most of the well-known hypoxia effects are mediated through hypoxia-inducible factors (HIF). Identification of the long-lasting effects of hypoxia beyond the immediate HIF-induced alterations could provide a better understanding of hypoxia-driven metastasis and potential strategies to circumvent it. Here, we uncovered a hypoxia-induced mechanism that exerts a prolonged effect to promote metastasis. In breast cancer patient-derived circulating tumor cell lines and common breast cancer cell lines, hypoxia downregulated tumor-intrinsic type I IFN signaling and its downstream antigen presentation (AP) machinery in luminal breast cancer cells, via both HIF-dependent and HIF-independent mechanisms. Hypoxia induced durable IFN/AP suppression in certain cell types that was sustained after returning to normoxic conditions, presenting a "hypoxic memory" phenotype. Hypoxic memory of IFN/AP downregulation was established by specific hypoxic priming, and cells with hypoxic memory had an enhanced ability for tumorigenesis and metastasis. Overexpression of IRF3 enhanced IFN signaling and reduced tumor growth in normoxic, but not hypoxic, conditions. The histone deacetylase inhibitor entinostat upregulated IFN targets and erased the hypoxic memory. These results point to a mechanism by which hypoxia facilitates tumor progression through a long-lasting memory that provides advantages for circulating tumor cells during the metastatic cascade. Significance: Long-term cellular memory of hypoxia leads to sustained suppression of tumor-intrinsic type I IFN signaling and the antigen presentation pathway that facilitates tumorigenesis and metastasis. See related commentary by Purdy and Ford, p. 3125.

Oxime-derived palladacycles bearing 2,6-lutidine: Synthesis, cytotoxicity evaluation and interactions with biomolecules

In this study, we report the synthesis, characterization and biological studies on new organometallic compounds bearing orthopalladated oximes and 2,6-lutidine. Cyclopalladated compounds of the type [PdCl(C2,N-ox)(lut)] {ox: bzox = benzaldehydeoxime (1), aphox = acetophenoneoxime (2), tetrox = E-α-tetralone oxime (3); lut = 2,6-lutidine} have been obtained from the reaction between the suitable [Pd(C2,N-ox)(µ-Cl)]2 precursor with 2,6-lutidine. The compounds have been characterized by elemental analyses, infrared (IR) and NMR spectroscopies. The molecular and crystal structures of 1 – 3 have been determined by single-crystal X-ray crystallography. The cytotoxic activity of compounds 1–3 has been evaluated towards breast (MCF-7 and MD-MBA-231) and lung (A549) human cancer cells along with human lung fibroblast (MRC-5). The level of cytotoxicity is dependent on the tested tumour cell line and the type of orthometallated oxime. The binding properties of the model compound 3 on ct-DNA have been studied using UV–Vis titration, circular dichroism and fluorescence spectroscopy.

CD8 + T-cells restrict the development of peritoneal metastasis and support the efficacy of hyperthermic intraperitoneal chemotherapy (HIPEC)

Multimodal therapy for peritoneal metastasis (PM) including cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) provides long-term survival in highly selected colorectal cancer patients. Mechanisms behind HIPEC are unknown and may include induction of adaptive immunity. We therefore analyzed human PM samples and explored the impact of HIPEC in experimental models. Human samples from colorectal primary tumors (n = 19) and PM lesions (n = 37) were examined for the presence of CD8 + T-cells and their association with disease free (DFS) and overall survival (OS). CD8 + T cell response after HIPEC was assessed using an in-vivo PM mouse model, tumor cell lines and patient-derived tumor organoids. Patients with high intraepithelial CD8 + T cell counts showed longer DFS and OS. In the mouse model, HIPEC controlled growth of PM and increased numbers of functional granzyme positive CD8 + T cells within tumors. Cell lines and human organoids that were treated with heated chemotherapies showed immunogenic changes, reflected by significantly higher levels of MHC-class I molecules and expression of Cancer Testis Antigens Cyclin A1 and SSX-4. Using in-vitro co-culture assays, we noticed that cancer cells treated with heated chemotherapy primed dendritic cells, which subsequently enhanced effector functions of CD8 + T cells. The presence of CD8 + T-cells within PM lesions is associated with prolonged survival of patients with PM. Data from PM mouse model and in-vitro assay show that heated chemotherapies induce immunogenic changes on cancer cells leading to induction of CD8 + T-cells mediated immunity, which seems to control growth of PM lesions in mice after HIPEC.

Three new cyclopentanoid monoterpenes from the roots of Picrorhiza scrophulariiflora

Three new cyclopentanoid monoterpenes, neopiscrocins A–C (1–3), together with 14 known compounds (4–17), were isolated from the roots of Picrorhiza scrophulariiflora. The structres of these compounds were elucidated on the basis of their spectroscopic data. All compounds were evaluated for cytotoxicity against six human tumor cell lines (PC9, PANC1, HCT-116, Hep-G2, BGC-823, and MCF-7), hepatoprotective activity and anti-inflammatory activity.

1,2,3-Triazole nilotinib analogues: Synthesis and Cytotoxic activity

Using the CuAAC reaction as a key step, a novel series of Nilotinib analogues was prepared by replacing the imidazole ring in the Nilotinib molecule with 1,2,3-triazole moiety via a divergent synthetic approach. The synthesized compounds were tested for cytotoxic activity against a series of tumor cell lines which included U251, PC-3, K562, HCT-15, MCF-7 and SKLU. Inhibition growth up to 85.6 % was observed for some compounds.

Fungal endophytes isolated from Withania somnifera Markedly exhibit antitumor activity against human glioblastoma

In the current study, five fungal endophytes (WR-1, WR-2, WR-3, WR-4, WS-6) were isolated from the roots and stem of Withania somnifera (L.) Dunal, and tested fungal culture filtrates (FCF) against the brain tumour (glioblastoma) cell line (U-87). All FCFs showed anti-tumour activity with an IC50 value of 3.5, 6.0, 3.2, 6.0, and 0.95 µg/mL, respectively. HPLC fractionation of WS-6 showed the presence of 11 compounds (A1–A11), all with good anti-tumour activities (IC 50 3.5, 5.0, 5.0, 3.6, 2.5, 1.7, 2.3, 2.7, 0.9, 1.8 and 0.4 µg/mL, respectively). We report for the first time, the anti-tumour activity of 1-Docosene, Phenol, 2,4-bis(1,1-dimethylethyl), 1,2-Benzenedicarboxylic acid, diisooctyl ester, Hexadecane, 1,1-bis(dodecyloxy)-, Benzene, 1,1'-(2-methyl-2-(phenylthio)cyclopropylidene) bis-, Naphthalene, 1,2-dihydro-1-phenyl- (A1–A6), identified by GC-MS. The rest (A7–A11) had earlier reports of anticancer activities on cell lines other than U-87. We conclude that endophytic WS-6 (Aspergillus fumigatus) produces antitumor compounds that might be helpful in future drug development against brain tumours, especially glioblastoma.

Tumor-induced endothelial RhoA activation mediates tumor cell transendothelial migration and metastasis.

The endothelial barrier plays an active role in transendothelial tumor cell migration during metastasis, however, the endothelial regulatory elements of this step remain obscure. Here we show that endothelial RhoA activation is a determining factor during this process. Breast tumor cell-induced endothelial RhoA activation is the combined outcome of paracrine IL-8-dependent and cell-to-cell contact β 1 integrin-mediated mechanisms, with elements of this pathway correlating with clinical data. Endothelial-specific RhoA blockade or in vivo deficiency inhibited the transendothelial migration and metastatic potential of human breast tumor and three murine syngeneic tumor cell lines, similar to the pharmacological blockade of the downstream RhoA pathway. These findings highlight endothelial RhoA as a potent, universal target in the tumor microenvironment for anti-metastatic treatment of solid tumors.

Synthesis, Absolute Configuration, Biological Profile and Antiproliferative Activity of New 3,5-Disubstituted Hydantoins.

Hydantoins, a class of five-membered heterocyclic compounds, exhibit diverse biological activities. The aim of this study was to synthesize and characterize a series of novel 3,5-disubstituted hydantoins and to investigate their antiproliferative activity against human cancer cell lines. The new hydantoin derivatives 5a-i were prepared as racemic mixtures of syn- and anti-isomers via a base-assisted intramolecular amidolysis of C-3 functionalized β-lactams. The enantiomers of syn-5a and anti-hydantoins 5b were separated by preparative high-performance liquid chromatography (HPLC) using n-hexane/2-propanol (90/10, v/v) as the mobile phase. The absolute configuration of the four allyl hydantoin enantiomers 5a was assigned based on a comparison of the experimental electronic circular dichroism (ECD) and vibrational circular dichroism (VCD) spectra with those calculated using density functional theory (DFT). The antiproliferative activity evaluated in vitro against three different human cancer cell lines: HepG2 (liver hepatocellular carcinoma), A2780 (ovarian carcinoma), and MCF7 (breast adenocarcinoma), and on the non-tumor cell line HFF1 (normal human foreskin fibroblasts) using the MTT cell proliferation assay. In silico drug-like properties and ADMET profiles were estimated using the ADMET Predictor ver. 9.5 and the online server admetSAR. Eighteen new 3,5-disubstituted hydantoins were synthesized and characterized. The compound anti-5c showed potent cytotoxic activity against the human tumor cell line MCF7 (IC50 = 4.5 µmol/L) and the non-tumor cell line HFF1 (IC50 = 12.0 µmol/L). In silico analyzes revealed that the compounds exhibited moderate water solubility and membrane permeability and are likely substrates for CYP3A4 and P-glycoprotein and have a high probability of antiarthritic activity.

PARP7 Inhibitors and AHR Agonists Act Synergistically Across a Wide-Range of Cancer Models.

Small molecule inhibitors of the mono (ADP) ribosyl transferase PARP7 are being evaluated as a monotherapy for tumors overexpressing PARP7 and in combination with immune checkpoint blockade. We previously showed that sensitivity to the PARP7 inhibitor (PARP7i) RBN-2397 could be enhanced by co-treatment with agonists of the Aryl Hydrocarbon Receptor (AHRa) in cell lines that show strong intrinsic sensitivity to RBN-2397. Here we demonstrate that a range of tumor cell lines that are relatively insensitive to PARP7i or AHRa as individual agents are unexpectedly profoundly sensitive to the combination. Our data show that this synergistic response is dependent on AHR/ARNT and is associated with increased levels of nuclear AHR and increased transcription of AHR target genes. In some hormone receptor-positive cell lines, we find that combination treatment is associated with proteasomal turnover of the steroid hormone receptors, androgen receptor and estrogen receptor. Both wildtype and hormone-resistant mutant forms of these receptors are degraded upon treatment with AHRa and PARP7i in breast and prostate cancer models. These results suggest that combining PARP7i with AHRa may extend the utility of these drugs to a wider range of tumors, including those that are refractory to hormone therapy.

Shilajit (Mumio) Elicits Apoptosis and Suppresses Cell Migration in Oral Cancer Cells Through Targeting Urokinase-type Plasminogen Activator and Its Receptor and Chemokine Signaling Pathways

Background Shilajit a natural phytomineral has a proven record of treating many human body ailments. Purpose This study aimed to explore the influence of Shilajit on cell proliferation and apoptosis induction in oral cancer cells (OCC) and to comprehend the molecular mechanism associated with OCC migration. Materials and Methods Human gingival fibroblast (hGF) and OCC (KB-1 (KERATIN-forming tumor cell line HeLa)) were exposed to Shilajit solution dilutions. Cell growth and apoptosis were measured by MTT and Annexin-V tests (control/test group). Cellular morphology using an inverted microscope, cellular apoptosis using acridine orange/ethidium bromide dual staining, reactive oxygen species production analysis using 2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA) staining, and gene protein expression using real-time polymerase chain reaction test were used to measure study outcomes. The data enumerated were the average of three trial experiments. Categorical and numerical data were expressed as frequency distribution and means, respectively. Differences in groups (control/test; zero/24 h/48 h) were determined using Student’s t-test and one way analysis of variance, with probability ‘ p’ value considered significant at ≤0.05. Results The viability of OCC exhibited a concentration and time-dependent response to Shilajit. Notably, Shilajit demonstrated selectivity against cancer cells. Through an examination of the Annexin-V apoptosis assay, it was observed that Shilajit induces apoptosis by upregulating the proapoptotic gene expression ( p ≤ 0.05) and downregulating antiapoptotic proteins ( p ≤ 0.05). Furthermore, the impact of Shilajit on cell migration decreased significantly when compared to control cells through modulating the urokinase-type plasminogen activator (uPA) and its receptor (uPAR) and chemokines gene expression. Conclusion Shilajit exhibited greater cytotoxicity, decreased OCC proliferation and migration, and initiated OCC apoptosis as equivalent to normal cells. These promising outcomes indicate that Shilajit holds potential as a robust, promising option for oral cancer treatment, underscoring the need for further research in this domain.

Phytochemical and pharmacological investigation of the non-volatile compounds of Lepidium cartilagineum (J. C. Mayer) Thell. and determination of the essential oil composition of its flowers and fruits

Eighteen compounds, among them phenylpropanoids (1–2), neolignans (3–9), a megastigmane (10), a phenyl glucoside (11), flavonoids (12–14), and N-containing compounds (15–18) were isolated from the methanolic extract of the whole plant of L. cartilagineum. The structures of the compounds were determined by NMR and MS measurements. The composition of the essential oils prepared from the flowers and fruits of L. cartilagineum was investigated using GC and GC–MS measurements. The essential oils were rich in aliphatic aldehydes and hydrocarbons, but low in sulfur-containing compounds, e.g., isothiocyanates. The extracts prepared from the aerial parts and roots of the plant, the essential oil, and the isolated compounds (1–9) were tested for antiproliferative activity against COLO 205 and COLO 320 cell lines and antibacterial activity on Lactobacillus rhamnosus. Dehydrodiconiferyl alcohol γ’-methyl ether (5) possessed marked antiproliferative activity against both human tumor cell lines. Neither the extracts nor the compounds affected the growth of the bacteria and did not influence the biofilm formation of L. rhamnosus. Based on the results, it can be concluded that L. cartilagineum is non-toxic to the human gut microbiome forming L. rhamnosus.

Synergistic anticancer effects and reduced genotoxicity of silver nanoparticles and tamoxifen in breast cancer cells

AbstractNanotechnology is emerging as a promising tool to enhance traditional cancer treatments due to rising chemotherapy resistance and the severe side effects of toxic drugs. Silver nanoparticles (AgNPs) are widely acknowledged for their antimicrobial and antiproliferative properties. Given these AgNP characteristics, this research conducts a comprehensive nanotoxicological assessment of strategic combinations involving AgNPs (68 nm) commercial formulation and tamoxifen on MCF‐7 and MDA‐MB‐231 breast tumor cells. Utilizing CompuSyn software, the combination index was determined, revealing a synergistic cytotoxic and antiproliferative effect in AgNPs and tamoxifen combinations (CI < 0.97). Furthermore, this combination impaired cell migration (the scratch zone expanded by over 270%) and significantly increased reactive oxygen species production (up to 96% for MDA‐MB‐231 and 52% for MCF‐7 cells). Surprisingly, the genotoxic effect of these mixtures was minimal (below the allowable genotoxicity index of 1.5). Additionally, both breast tumor cell lines exhibited increased proapoptotic and oxidative stress gene expression following the combined treatment. The internalization of AgNPs into breast cancer cells was observed, enhancing their synergistic antiproliferative effect when combined with tamoxifen. These findings suggest the potential of combining AgNPs with chemotherapeutic agents for innovative studies in oncology therapy.

Abstract C113: Parabens promote cell growth in cancer cell lines associated with health disparities

Abstract Parabens are endocrine-disrupting chemicals used as preservatives to extend the shelf life of consumables, pharmaceuticals, and personal care products. Daily use of products containing parabens results in continuous exposure that can negatively impact health. It is known that parabens cause breast cancer cells to grow and express genes linked to cancer and hormone action. Our lab previously showed that parabens increase viability of and regulate estrogen-responsive gene expression in diverse luminal A breast cancer cell lines. In addition, greater effects were seen in a luminal A cell line of West African ancestry compared to one of European ancestry, suggesting that exposure to parabens in personal care products may contribute to breast cancer disparities. Therefore, the purpose of this study was to investigate whether parabens increase cell viability across a variety of cancer cell types, particularly those associated with cancer disparities. To do so, we utilized the National Cancer Institute-60 (NCI-60) Human Tumor Cell Lines screen that includes leukemia, non-small cell lung (NSCL), colon, central nervous system (CNS), melanoma, ovarian, renal, prostate, and breast cancer cell lines, plus a custom panel of pancreatic cancer cell lines. Of these, ovarian, NSCL, prostate, colon, renal, CNS, and pancreatic cancers have known disparities. We treated these cancer cell lines with biologically relevant doses of butylparaben (BP), methylparaben (MP), or propylparaben (PP) (doses ranging from 0.0012 µM – 20 µM) for 72 hours and measured cell viability. Treatment with dimethylsulfoxide or 10 nM estradiol served as negative and positive controls, respectively. In general, we observed a paraben-specific and cell-line specific effect on cell viability. MP exhibited the greatest effect with increased cell viability in 42% of the cell lines, followed by PP (38%), and BP (32%). MP and PP are among the most common parabens found in personal care products and differences in urinary levels based on race/ethnicity (e.g. higher levels in non-Hispanic Blacks/Mexican Americans compared to non-Hispanic Whites) have been reported. Breast, ovarian, and NSCL had the most cell lines (67-83%) that exhibited increased cell viability with any paraben treatment. Increased cell viability was also observed in several leukemia, colon, pancreatic, CNS, and melanoma cell lines (33-50%). Only one renal, and no prostate, cell line exhibited increased cell viability. These data suggest that paraben-mediated protumorigenic effects may promote cancer disparities beyond breast cancer. Studies are currently underway to determine the mechanisms underlying this link. One caveat of this study is that most of the cell lines in this readily available screen are of European ancestry, highlighting a need to develop more genetically diverse in vitro models for understanding the mechanistic link between paraben exposures and cancer risk/outcomes in the context of disparities. Approaching this challenge from an endocrinology and genetic ancestry perspective may help narrow the disparity gap. Citation Format: Jazma L. Tapia, Jillian C. McDonough, Loretta Erhunmwunsee, Lindsey S. Trevino. Parabens promote cell growth in cancer cell lines associated with health disparities [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C113.

Synthesis and Antiproliferative Activity of Cisplatin-3-Chloropiperidine Conjugates.

We report the synthesis and characterization of two novel cisplatin- alkylating agents conjugates. Combining a platinum based cytostatic agent with a sterically demanding alkylating agent could potentially induce further DNA damage, block cell repair mechanisms and keep the substrate active against resistant tumor cell lines. The 3-chloropiperidines utilized as ligands in this work are cyclic representatives of the N-mustard family and were not able to coordinate platinum on their own. The introduction of a second coordination site, in form of a pyridine moiety, led to the isolation of the desired conjugates. They were characterized with HRMS, CHN-analyses and XRD. We concluded this work by examining the cytotoxicity of the ligands and the obtained complexes with MTT assays in human cancer cell lines. While the ligands showed hardly any activity, the novel conjugates both displayed a high antiproliferative and cytotoxic potency in a panel of three cell lines. Moreover, both complexes were able to largely circumvent the acquired cisplatin resistance of A2780cisR ovarian cancer cells, both in the MTT assay and a flow-cytometric apoptosis assay.

Regulation of corticosteroid-binding globulin release in murine leydig tumor cell line mLTC-1 by luteinizing hormone and interleukin-6

Exogenous assaults interfere with homeostatic processes in the body by inducing stress responses. Corticosteroid-binding globulin (CBG) binds to stress hormone glucocorticoids to transport and dynamically control their availability to target tissues. In our previous study, we confirmed that CBG is locally produced by Leydig cells in the testes. Here, we explored the potential regulators of CBG using a murine Leydig tumor cell line (mLTC-1). Results indicated that luteinizing hormone (LH) and interleukin-6 (IL-6) were important factors stimulating the release of CBG from mLTC-1 cells. In addition, IL-6 stimulated mLTC-1 cells to release alpha-1 antitrypsin (AAT), a serine proteinase inhibitor (serpin) that affects CBG conformation. The results implied that any challenge that altered LH or IL-6 levels also changed the release and binding status of CBG with steroid hormones in the testicular microenvironment and modulated cellular responses to these stress hormones. In addition, secretory proteomic analysis indicated that the extracellular matrix (ECM), cytoskeleton, and proteasomes were essentially produced by the mLTC-1 cells, and LH evoked the secretion of proteins involved in binding and metabolism. These results emphasize that Leydig cells may undertake more functions than just steroidogenesis, and the regulation of Leydig cells by LH is versatile.