Cervical Tumor Cell Lines Research Articles

Abstract 5408: SERPINB3 impact on cervical cancer cell mobility and migration

Abstract Cervical cancer is the fourth most common cancer in women, with 311,000 deaths worldwide in 2018. About two thirds of patients with cervical cancer exhibit elevated serum levels of squamous cell carcinoma antigen (SCCA), also known as SERPINB3. SERPINB3 is associated with advanced stage and lymph node metastasis and we have previously shown it has a protective role against radiation treatment and chemotherapy induced cell death. We have also shown that SERPINB3 promotes tumor growth in both immunocompromised and immune competent murine models, yet the molecular mechanism is unknown. We have recently shown that SERPINB3 expression results in activation of signal transducer of transcription 3 (STAT3) and extracellular signal regulated kinase (ERK) in cervical cancer cells. These signaling cascades promote cell proliferation, survival, invasion, and metastasis. Proximity labeling using biotin-ligase fused to SERPINB3 revealed STAT3 and ERK as potential interacting partners. We aim to identify the molecular mechanism by which SERPINB3 promotes tumor progression, and determine if SERPINB3 drives invasion and metastasis in-vivo. We hypothesized that SERPINB3 directly interacts with and activates STAT3 and ERK leading to downstream signaling promoting invasion and metastasis. To test this hypothesis, we used cervical tumor cell lines engineered with SERPINB3 or empty vector control and determined migration by wound healing assay and downstream activation of STAT3 and ERK. Co-immunoprecipitation (co-IP) with western blot was performed to determine an interaction between SERPINB3 and STAT3 and ERK. E6/E7-expressing TC-1, and Lewis Lung Carcinoma cells, LL2, to develop a method for injecting the cervix of immunocompetent c57BL/6 albino mice (no available murine cervical carcinoma line). Wound healing assays revealed that knocking out SERPINB3 shows a decrease in wound closure in both SW756 and HT3 cervical cancer cells compared to control cells, respectively. Co-IP of STAT3 in HT3 cells revealed the presence of SERPINB3, providing further evidence for an interaction between STAT3 and SERPINB3. We were able to grow tumors in the cervix of the C57/BL6 mice and identified potential metastatic deposits in the lung. Moving forward, we plan to identify the minimal functional domain of the interaction between SERPINB3 and STAT3/ERK using a step-wise genetic approach for protein domain deletion. To determine the role of SERPINB3 on metastasis in vivo, we will use, LL2 and TC-1 engineered with the mouse orthologue mSERPINB3a to determine effect of SERPINB3 on invasion and metastasis. Conducting this study will provide insights as to how SERPINB3 may function in a pro-tumor role in cervical cancer and allow the development of SERPINB3-targeted drugs. Citation Format: Marlene L. Campos Guerrero, Li-Yun Chen, Stephanie Markovina. SERPINB3 impact on cervical cancer cell mobility and migration [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5408.

Yellow scorpion (Buthus sinidicus) venom peptides induce mitochondrial-mediated apoptosis in cervical, prostate and brain tumor cell lines.

Scorpion venoms are known to contain over 100,000 biologically active constituents. However, only a few of them have been studied. The major constituents of venom are proteins and peptides, which exhibit various biological and pharmacological properties, including anticancer activities. In the current study, the venom of yellow scorpions (Buthus sindicus) found in Sindh, Pakistan, was extracted and evaluated for its anti-cancer and anti-inflammatory activities. The crude venom showed a dose dependent inhibition of phagocyte oxidative burst from human whole blood cells (28.3% inhibition at highest tested concentration of 300 μg/mL). In-vitro cytotoxicity of crude venom was evaluated against human prostrate (PC3), cervical (HeLa) and neuroblastoma (U87-MG) cell lines, along with cytotoxicity against normal human fibroblast (BJ) cells. Crude venom was cytotoxic to all cell lines, with prominent inhibitory effect on PC3 cells. Crude venom was fractionated through RP-UPLC, resulted in fifteen fractions, followed by evaluation of their anticancer potential. Among all, the fraction I significantly (P < 0.001) reduced the cell viability of all three cancer cell lines, and exhibited insignificant cytotoxicity against normal cell line. Furthermore, the apoptotic cell death pathway was evaluated for crude venom, and fraction I, in most sensitive cell line PC3, by using flow-cytometry analysis. Both crude venom and its fraction I caused a mitochondrial-mediated apoptosis in prostate cancer cells (PC3). To the best of our knowledge, this is the first report of the anticancer and anti-inflammatory activity of venom of Pakistani yellow scorpions. Results indicate their therapeutic potential, and a case for further purification and validation studies.

Heterogeneous Response of Tumor Cell Lines to Inhibition of Aspartate β-hydroxylase.

Background: Cancer development involves alterations in key cellular pathways, with aspartate β-hydroxylase (ASPH) emerging as an important player in tumorigenesis. ASPH is upregulated in various cancer types, where it promotes cancer progression mainly by regulating the Notch1 and SRC pathways. Methods: This study explored the responses of various human cervical, pharyngeal, and breast tumor cell lines to second- and third-generation ASPH inhibitors (MO-I-1151 and MO-I-1182) using proliferation, migration, and invasion assays; western blotting; and cell cycle analysis. Results: ASPH inhibition significantly reduced cell proliferation, migration, and invasion and disrupted both the canonical and noncanonical Notch1 pathways. The noncanonical pathway was particularly mediated by AKT signaling. Cell cycle analysis revealed a marked reduction in cyclin D1 expression, further confirming the inhibitory effect of ASPH inhibitors on cell proliferation. Additional analysis revealed G0/G1 arrest and restricted progression into S phase, highlighting the regulatory impact of ASPH inhibitors on the cell cycle. Furthermore, ASPH inhibition induced distinctive alterations in nuclear morphology. The high heterogeneity in the responses of individual tumor cell lines to ASPH inhibitors, both quantitatively and qualitatively, underscores the complex network of mechanisms that are regulated by ASPH and influence the efficacy of ASPH inhibition. The effects of ASPH inhibitors on Notch1 pathway activity, cyclin D1 expression, and nuclear morphology contribute to the understanding of the multifaceted effects of these inhibitors on cancer cell behavior. Conclusion: This study not only suggests that ASPH inhibitors are effective against tumor cell progression, in part through the induction of cell cycle arrest, but also highlights the diverse and heterogeneous effects of these inhibitors on the behavior of tumor cells of different origins.

Isolation and NMR Scaling Factors for the Structure Determination of Lobatolide H, a Flexible Sesquiterpene from Neurolaena lobata

A new flexible germacranolide (1, lobatolide H) was isolated from the aerial parts of Neurolaena lobata. The structure elucidation was performed by classical NMR experiments and DFT NMR calculations. Altogether, 80 theoretical level combinations with existing 13C NMR scaling factors were tested, and the best performing ones were applied on 1. 1H and 13C NMR scaling factors were also developed for two combinations utilizing known exomethylene containing derivatives, and the results were complemented by homonuclear coupling constant (JHH) and TDDFT-ECD calculations to elucidate the stereochemistry of 1. Lobatolide H possessed remarkable antiproliferative activity against human cervical tumor cell lines with different HPV status (SiHa and C33A), induced cell cycle disturbance and exhibited a substantial antimigratory effect in SiHa cells.

Antitumor Effect of Chalcone Derivatives against Human Prostate (LNCaP and PC-3), Cervix HPV-Positive (HeLa) and Lymphocyte (Jurkat) Cell Lines and Their Effect on Macrophage Functions

Chalcones are synthetic and naturally occurring compounds that have been widely investigated as anticancer agents. In this work, the effect of chalcones 1-18 against the metabolic viability of cervical (HeLa) and prostate (PC-3 and LNCaP) tumor cell lines was tested, to compare the activity against solid and liquid tumor cells. Their effect was also evaluated on the Jurkat cell line. Chalcone 16 showed the highest inhibitory effect on the metabolic viability of the tested tumor cells and was selected for further studies. Recent antitumor therapies include compounds with the ability to influence immune cells on the tumor microenvironment, with immunotherapy being one actual goal in cancer treatment. Therefore, the effect of chalcone 16 on the expression of mTOR, HIF-1α, IL-1β, TNF-α, IL-10, and TGF-β, after THP-1 macrophage stimulation (none, LPS or IL-4), was evaluated. Chalcone 16 significantly increased the expression of mTORC1, IL-1β, TNF-α, and IL-10 of IL-4 stimulated macrophages (that induces an M2 phenotype). HIF-1α and TGF-β were not significantly affected. Chalcone 16 also decreased nitric oxide production by the RAW 264.7 murine macrophage cell line, this effect probably being due to an inhibition of iNOS expression. These results suggest that chalcone 16 may influence macrophage polarization, inducing the pro-tumoral M2 macrophages (IL-4 stimulated) to adopt a profile closer to the antitumor M1 profile.

Construction of a Stimuli-Responsive DNAzyme-Braked DNA Nanomachine for the Amplified Imaging of miRNAs in Living Cells and Mice

Construction of a Stimuli-Responsive DNAzyme-Braked DNA Nanomachine for the Amplified Imaging of miRNAs in Living Cells and Mice

Alkaloid Profiling, Anti-Enzymatic and Antiproliferative Activity of the Endemic Chilean Amaryllidaceae Phycella cyrtanthoides

This research aims to identify the alkaloid profile and to evaluate the enzyme inhibitory potential and antiproliferative effects of the Amaryllidaceae plant Phycella cyrtanthoides. The alkaloid extracts from bulbs and leaves were analyzed using ultrahigh performance liquid chromatography orbitrap mass spectrometry (UHPLC-Orbitrap-MS) analysis. A total of 70 alkaloids were detected in the P. cyrtanthoides’ extracts. The enzyme inhibition potential against cholinesterases (AChE: acetylcholinesterase, and BChE butyrylcholinesterase) and tyrosinase were studied. Bulbs displayed the best IC50 values against AChE (4.29 ± 0.03 µg/mL) and BChE (18.32 ± 0.03 µg/mL). These results were consistent with docking experiments with selected major compounds in the active sites of enzymes, while no activity was observed against tyrosinase enzyme. Antiproliferative effects were investigated against human cervical (HeLa), lung (A549, SW1573), colon (WiDr), and breast (HBL-100, T-47D) tumor cell lines. Bulbs and leaves were active in all cell lines (GI50 < 2.5 µg/mL). These findings suggest that the endemic Chilean plant P. cyrtanthoides contains diverse types of bioactive alkaloids with antiproliferative activities and inhibitory effects with potential therapeutic applications for neurodegenerative diseases

Isolation, Structure Determination of Sesquiterpenes from Neurolaena lobata and Their Antiproliferative, Cell Cycle Arrest-Inducing and Anti-Invasive Properties against Human Cervical Tumor Cells.

Seven new germacranolides (1–3, 5–8), among them a heterodimer (7), and known germacranolide (4), eudesmane (9) and isodaucane (10) sesquiterpenes were isolated from the aerial parts of Neurolaena lobata. Their structures were determined by using a combination of different spectroscopic methods, including HR-ESIMS and 1D and 2D NMR techniques supported by DFT-NMR calculations. The enantiomeric purity of the new compounds was investigated by chiral HPLC analysis, while their absolute configurations were determined by TDDFT-ECD and OR calculations. Due to the conformationally flexible macrocycles and difficulties in assigning the relative configuration, 13C and 1H NMR chemical shift and ECD and OR calculations were performed on several stereoisomers of two derivatives. The isolated compounds (1–10) were shown to have noteworthy antiproliferative activities against three human cervical tumor cell line with different HPV status (HeLa, SiHa and C33A). Additionally, lobatolide C (6) exhibited substantial antiproliferative properties, antimigratory effect, and it induced cell cycle disturbance in SiHa cells.

The augment of regulatory T cells undermines the efficacy of anti-PD-L1 treatment in cervical cancer

BackgroundImmune checkpoint inhibitors have aroused great expectation of tumor eradication. However, the effect of anti-PD-L1 treatment for cervical cancer is unsatisfactory and the underlying antagonist to anti-PD-L1 efficacy is remained to be studied. Here, we investigated the anti-tumor effect of anti-PD-L1 treatment in cervical tumor model and identified the antagonist to the therapeutic efficacy of anti-PD-L1 treatment.ResultsWe found that PD-L1 exhibited a moderate expression in both cervical tumor cell lines and clinical samples compared to other tumor types and the para-tumor tissue respectively. Interestingly, our results showed that the anti-PD-L1 treated mice were dichotomously divided into responsive and unresponsive group after five cycles of anti-PD-L1 treatment although all the mice had the same genome background. In addition, the unresponsive tumors showed less tumor necrosis area and higher immunosuppression activity induced by regulatory T cells (Tregs) population than the responsive ones. Furthermore, we found that anti-PD-L1 treatment autonomously upregulated Tregs proliferation and frequency in multiple immune organs, and, most importantly, Tregs depletion significantly depressed the tumor growth rate and tumor weight compared with either anti-PD-L1 or anti-CD25 treatment alone. Finally, we observed that the upregulating effector CD8+ T cell is associated with the better therapeutic effect of anti-PD-L1 therapy post Tregs depletion.ConclusionsAnti-PD-L1 treatment upregulates Tregs frequency and proliferation in tumor model, and the depletion of Tregs may be a useful adjuvant strategy for anti-PD-L1 therapy of cervical cancer.

LncRNA MALAT1 Accelerates Cervical Carcinoma Proliferation by Suppressing miR-124 Expression in Cervical Tumor Cells.

Emerging studies have clarified the critical role of LncRNA MALAT1 in various pathological progressions. Here, we identified its positive relationship with cervical carcinoma proliferation. Cervical carcinoma has been considered as one of the most malignant tumors among female. Thus, our study was designed to investigate the underlying mechanism of LncRNA MALAT1 on cervical tumor cell proliferation. We observed that miR-124 was the potential target of LncRNA MALAT1 in cervical tumor cell lines (Hela, C-33A, Caski, and SiHa), the expression level of which is negatively correlated with LncRNA MALAT1 in cervical tumor cells, tissues of cervical patients, and mice. Gain- or loss-of-function analyses in cervical tumor cells have further verified the regulatory role of MALAT1 on miR-124. Additionally, the proliferation of cervical carcinoma was inhibited by miR-124 overexpression, whereas it was blocked by LV-MALAT1 transfection. In vivo assays, overexpression of miR-124, or knockdown of MALAT1 exhibited beneficial effects on tumor weight, size, and volume, together with elevating the survival rate, tightly related with the progression of cervical cancer. In conclusion, LncRNA MALAT1 disabled the effects of miR-124 as an inhibitory sponge, accelerating the progression of cervical carcinoma.

ASN004, A 5T4-targeting scFv-Fc Antibody-Drug Conjugate with High Drug-to-Antibody Ratio, Induces Complete and Durable Tumor Regressions in Preclinical Models.

The 5T4 oncofetal antigen (trophoblast glycoprotein) is expressed in a wide range of malignant tumors but shows very limited expression in normal adult tissues. ASN004 is a 5T4-targeted antibody-drug conjugate (ADC) that incorporates a novel single-chain Fv-Fc antibody and Dolaflexin drug-linker technology, with an Auristatin F hydroxypropylamide payload drug-to-antibody ratio of approximately 10-12. The pharmacology, toxicology, and pharmacokinetic properties of ASN004 and its components were investigated in vitro and in vivo ASN004 showed high affinity for the 5T4 antigen and was selectively bound to and internalized into 5T4-expressing tumor cells, and potent cytotoxicity was demonstrated for a diverse panel of solid tumor cell lines. ASN004 induced complete and durable tumor regression in multiple tumor xenograft models, derived from human lung, breast, cervical, and gastric tumor cell lines having a wide range of 5T4 expression levels. A single dose of ASN004, as low as 1 mg/kg i.v., achieved complete tumor regression leading to tumor-free survivors in the A431 cervical cancer model. In head-to-head studies, superior activity of ASN004 was demonstrated against trastuzumab-DM1, in a low-5T4/high-HER2 expressing gastric tumor model, and 10-fold greater potency was found for ASN004 against the 5T4-targeted ADC PF-06263507 in a lung tumor model. In marmoset monkeys, ASN004 was well tolerated at doses up to 1.5 mg/kg Q3W i.v., and showed dose-dependent exposure, linear pharmacokinetics, and markedly low exposure of free payload drug. Taken together, these findings identify ASN004 as a promising new ADC therapeutic for clinical evaluation in a broad range of solid tumor types.

Abstract 2426: SERPINB3 promotes radiation resistance in cervical cancer by inhibiting lysosome-mediated cell death

Abstract The purpose of this study was to determine if squamous cell carcinoma antigen (SCCA), also known as SERPINB3, protects cervical cancer cells from ionizing radiation (IR)-induced death, and to determine the mechanism(s) of IR-induced cell death with or without SERPINB3. Cervical cancer remains a leading cause of cancer death in women worldwide despite advances in screening, vaccination and treatment. Recurrence after definitive chemoradiation occurs in up to 30-50% of patients with locally advanced disease. We and others have demonstrated that elevated serum SCCA portends poor prognosis in cervical cancer. In addition, CRISPR-Cas9-mediated knock out of SERPINB3 significantly sensitizes cervical tumor cells to IR in vitro. We hypothesize that SERPINB3 promotes radioresistance by protecting cells against lysosome damage and lysosomal mediated necrosis. Two cervical cancer cell lines with high SERPINB3 expression were edited using CRISPR-Cas9 technology at the SERPINB3 locus resulting in knock out (KO). B3-KO cells were significantly more radiation sensitive compared to control cells at all doses and time points evaluated. Cell death morphology in the B3-KO cells was necrotic, with large cytoplasmic single membraned vesicles, many of which were ruptured, consistent with that seen in lysosome-mediated necrosis. Live-cell time-lapse imaging showed loss of lysosome integrity in the hours leading up to cell death (propidium iodide nuclear staining). Western blot analysis showed low levels of caspase-3 and caspase-7 cleavage only at high doses and late time points after IR, with no evidence of phospho-MLKL or phospo-RIPK3 (markers of necroptosis), or gasdermin-D cleavage (marker of pyroptosis). Necrostatin, ferrostatin, liproxstatin and YVAD-Cho had little to no effect on cell death following IR, while pan-caspase inhibitors decreased IR-induced cell death in both control and B3-KO cells, and E64D decreased IR-induced cell death in B3-KO cells to a greater degree than control cells. Additionally, cervical tumor cell lines that had no detectable expression of SERPINB3 were engineered to expressed high levels of SERPINB3 (B3-wt) or SERPINB3 containing the P14 mutation A351R (B3-P14m), which lacks protease inhibitory function. B3-wt expressing cells displayed increased radiation resistance in clonogenic survival assays and mouse tumor models. Growth rate and radiation response of B3-p14m expressing tumors was similar to vector control. These data suggest that SERPINB3 is an important mediator of radiation response in cervical cancer and protects cells by inhibiting cysteine protease-dependent cell death, likely via lysosome-mediated necrosis. These findings support SERPINB3 as a potential target for novel radiosensitizing therapies. Citation Format: Songyan Wang, Clifford Luke, Victoria Shi, Perry Grigsby, Gary Silverman, Stephanie Markovina. SERPINB3 promotes radiation resistance in cervical cancer by inhibiting lysosome-mediated cell death [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2426.

Securidaca-saponins are natural inhibitors of AKT, MCL-1, and BCL2L1 in cervical cancer cells.

IntroductionScientific research is beginning to prove the connection between claims by African traditional medicine and the natural chemical specifics contained in medicinal plant Securidaca longipedunculata. Our previous studies showed that two natural saponin fractions (4A3 and 4A4) identified in the plant as triterpenoid glycosides are capable of activating apoptosis on cervical tumor cell lines. Considering this and some critical roles of human papillomavirus (HPV) E6 oncogene on cervical cells, by promoting carcinogenesis and cell survival, it became necessary to investigate the possible pathways for apoptosis transmission.MethodsTests conducted on relevant cervical tumor cell lines such as Caski and Bu25TK included the following: MTT assay; scratch assay (to determine cell migration/invasion); fluorescence microscopy with Annexin V–fluorescein isothiocyanate, muscle progenitor cell) and propidium iodide staining; and finally reverse transcriptase quantitative PCR (RT-qPCR) for gene analysis.ResultsReduced cell proliferation was observed due to activities of 4A3 and 4A4 fractions, with half-maximal inhibitory concentration (IC50) of 7.03 and 16.39 μg/mL, respectively, on Caski cell line. A significant reduction in cell migration occurred within 48 and 72 hours, respectively, for Caski and Bu25TK cell lines. Late apoptosis was activated by 4A3, staining both Annexin V and PI, in contrast to 4A4’s early apoptosis. RT-qPCR data revealed a fold change (FC) inhibition of antiapoptotic proteins such as MCL-1 and BCL2L1, with diminished level of AKT-3, VEGFA, MALAT1, etc. The expression of p53, proapoptotic BAD, and caspase-8 was nonsignificant.ConclusionThe low expression of AKT-3 and antiapoptotic proteins (MCL-1 and BCL2L1), as well as VEGFA, could simply be an indication for possible suppression of cell survival mechanisms via multiple channels. We therefore conclude that 4A3 and 4A4 fractions mediate activity via the inhibition of phosphatidylinositol-3-OH kinase (PI3K)-AKT/mTOR/NF-kB-dependent antiapoptotic stimuli. Further studies are ongoing to reveal the chemical structures and compositions of these two fractions.

Synthesis of Artemisinin-Estrogen Hybrids Highly Active against HCMV, P. falciparum, and Cervical and Breast Cancer.

Artemisinin-estrogen hybrids were for the first time both synthesized and investigated for their in vitro biological activity against malaria parasites (Plasmodium falciparum 3D7), human cytomegalovirus (HCMV), and a panel of human malignant cells of gynecological origin containing breast (MCF7, MDA-MB-231, MDA-MB-361, T47D) and cervical tumor cell lines (HeLa, SiHa, C33A). In terms of antimalarial efficacy, hybrid 8 (EC50 = 3.8 nM) was about two times more active than its parent compound artesunic acid (7) (EC50 = 8.9 nM) as well as the standard drug chloroquine (EC50 = 9.8 nM) and was, therefore, comparable to the clinically used dihydroartemisinin (6) (EC50 = 2.4 nM). Furthermore, hybrids 9-12 showed a strong antiviral effect with EC50 values in the submicromolar range (0.22-0.38 μM) and thus possess profoundly stronger anti-HCMV activity (approximately factor 25) than the parent compound artesunic acid (7) (EC50 = 5.41 μM). These compounds also exerted a higher in vitro anti-HCMV efficacy than ganciclovir used as the standard of current antiviral treatment. In addition, hybrids 8-12 elicited substantially more pronounced growth inhibiting action on all cancer cell lines than their parent compounds and the reference drug cisplatin. The most potent agent, hybrid 12, exhibited submicromolar EC50 values (0.15-0.93 μM) against breast cancer and C33A cell lines.

Abstract B109: ASN004, a novel 5T4-targeted Dolaflexin ADC, causes complete and durable tumor regression in a variety of tumor xenograft models

Abstract The 5T4 oncofetal antigen (trophoblast glycoprotein) is expressed in a wide range of malignant tumors, while showing very limited expression in normal adult tissues. This selective pattern of expression establishes 5T4 as an attractive therapeutic target for the Antibody-Drug Conjugate (ADC) strategy. ASN004 is an anti-5T4 ADC that incorporates a novel single-chain homo-dimer antibody, Fleximer® linker technology (Mersana Therapeutics), and cytotoxic dolastatin (auristatin) analog warheads, with a drug/antibody ratio of ~15:1. ASN004 shows high affinity for the 5T4 antigen (Kd &amp;lt; 30 pM), with selective binding and internalization to 5T4-expressing tumor cells. Potent, selective cytotoxicity has been determined for a diverse panel of tumor cell lines. ASN004 provides complete and durable tumor regression in multiple tumor xenograft models, derived from human lung, breast, cervical, and gastric tumor cell lines having a range of 5T4 expression levels. Tumor-free survivors could be achieved in tumor models with a single dose of ASN004, as low as 1 mg/kg iv. The broad, superior activity of ASN004 was demonstrated in a head-to-head study against trastuzumab-DM1, in a low-5T4/high-HER2 expressing tumor model. Finally, efficacy of ASN004 in patient-derived tumor xenograft (PDX) models will be presented. In summary, ASN004 has been established as a promising ADC therapeutic for multiple tumor types, encompassing a wide range of 5T4-expression levels. IND-enabling studies are ongoing in preparation for advancement to clinical development. Citation Format: Roger A. Smith, David J. Zammit, Sanjeeva P. Reddy. ASN004, a novel 5T4-targeted Dolaflexin ADC, causes complete and durable tumor regression in a variety of tumor xenograft models [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B109.

Anti-tumour effects of polysaccharide extracted from Acanthopanax senticosus and cell-mediated immunity.

Acanthopanax senticosus, also known as Siberian ginseng, is widely distributed throughout northern Asia and used in traditional Chinese medicine; it has been reported to prevent a number of diseases. However, the association between the antitumour and immunostimulatory activities of polysaccharide extracted from A. senticosus (ASPS) remains to be elucidated. The aim of the present study was to investigate the anti-tumour and immunomodulatory effects of polysaccharide extracted from ASPS on Crocker sarcoma S180, hepatic carcinoma H22 and uterine cervical carcinoma U14 tumour cell lines implanted in mice. High performance liquid chromatography, gas chromatography and infrared spectroscopy were used to analyse the monosaccharide composition of ASPS. The monosaccharide composition of ASPS (Arabic candy: Xylose: Glucose: Mannose) was 7.1:22.3:7.6:1.0. On day 0, female Kunming mice, were injected subcutaneously with 1×108 tumour cells in 0.2 ml. The inoculated mice were subsequently divided into five groups (10 mice/group) as follows: Model group, treated with normal saline; positive control group, treated with 30 mg/kg cyclophosphamide (CTX); and three treatment groups, treated with 200, 100 or 50 mg/kg ASPS. Non-inoculated mice were divided into the normal group, which was treated with normal saline, and the negative control group, which was treated with 200 mg/kg ASPS (n=10/group). CTX and ASPS were administered intragastrically once daily for 10 days. All mice were sacrificed on day 11. ASPS was observed to have an inhibitory effect on the growth of S180, H22 and U14 cells in solid and ascites tumour-bearing mice. Serum interleukin (IL)-2 and IL-12 levels were significantly increased in S180 solid tumour-bearing mice treated with 200 or 100 mg/kg ASPS compared with mice in the normal, control and model groups (P<0.05), whereas serum IL-2 and IL-12 levels were significantly decreased in the cyclophosphamide treatment group compared with the normal, control and model groups (P<0.05). No significant difference in serum levels of tumour necrosis factor-α level was observed between any groups. In S180 and U14 solid tumour-bearing mice, no significant differences in serum levels of interferon (INF)-γ level in were observed between groups; however, in H22 solid tumour-bearing mice, treatment with ASPS significantly increased serum INF-γ compared with the positive control group (P<0.05). The results may provide a basis for the potential application of ASPS in clinical treatment for cancer.

Serum squamous cell carcinoma antigen as an early indicator of response during therapy of cervical cancer

Background:Pretreatment serum squamous cell carcinoma antigen (SCCA) is a prognostic biomarker in women with cervical cancer. SCCA has not been evaluated as an early indicator of response to chemoradiation therapy (CRT). The molecular role of the two SCCA isoforms, SCCA1 (SERPINB3) and SCCA2 (SERPINB4), in cervical cancer is unknown. We hypothesised that changes in serum SCCA during definitive CRT predicts treatment response, and that SCCA1 mediates radiation resistance.Methods:Patients treated with definitive CRT for cervical squamous carcinoma with serum SCCA measured were included. SCCA immunohistochemistry was performed on tumour biopsies. Post-treatment FDG-PET/CT, recurrence, and overall survival were recorded. Radiation response of cervical tumour cell lines after SCCA1 expression or CRISPR/Cas9 knockout was evaluated by clonogenic survival assay.Results:Persistently elevated serum SCCA during definitive CRT was an independent predictor of positive post-therapy FDG-PET/CT (P=0.043), recurrence (P=0.0046) and death (P=0.015). An SCCA1-expressing vector increased radioresistance, while SCCA knock out increased radiosensitivity of cervical tumour cell lines in vitro.Conclusions:Early response assessment with serum SCCA is a powerful prognostic tool. These findings suggest that escalation of therapy in patients with elevated or sustained serum SCCA and molecular targeting of SCCA1 should be considered.

Platelet derived TGF-β promotes cervical carcinoma cell growth by suppressing KLF6 expression.

Platelets in the primary tumor microenvironment play crucial roles in regulating tumor growth, metastasis, and angiogenesis, but the underlying mechanisms are unclear. Here, we show that platelet releasates exhibited a proliferative effect on HeLa cells, and this effect correlated with a reduction of KLF6 expression. After incubation with either washed human platelets or collagen-related peptide (CRP) activated platelet releasates, expression of KLF6 in the HeLa cervical tumor cell line was markedly reduced. However, no significant difference was observed between control HeLa cells and HeLa cells incubated with resuspended activated platelet pellet. Moreover, the platelets’ promoting effect on HeLa cell growth was significantly abolished in KLF6 silenced HeLa cells. In addition, blocking TGF-β signaling with SB431542, a TGF-β receptor inhibitor, also counteracted the effect of platelets on proliferation and KLF6 expression in HeLa cells. From these findings, we conclude that platelet derived TGF-β promotes proliferation of HeLa cells by decreasing the expression of KLF6. The discovery that KLF6 is a key target of platelet-derived TGF-β signaling in HeLa cells identifies a potential new therapeutic target for the prevention and treatment of cervical carcinoma.

TXNDC5 is a cervical tumor susceptibility gene that stimulates cell migration, vasculogenic mimicry and angiogenesis by down-regulating SERPINF1 and TRAF1 expression.

TXNDC5 (thioredoxin domain-containing protein 5) catalyzes disulfide bond formation, isomerization and reduction. Studies have reported that TXNDC5 expression is increased in some tumor tissues and that its increased expression can predict a poor prognosis. However, the tumorigenic mechanism has not been well characterized. In this study, we detected a significant association between the rs408014 and rs7771314 SNPs at the TXNDC5 locus and cervical carcinoma using the Taqman genotyping method. We also detected a significantly increased expression of TXNDC5 in cervical tumor tissues using immunohistochemistry and Western blot analysis. Additionally, inhibition of TXNDC5 expression using siRNA prevented tube-like structure formation, an experimental indicator of vasculogenic mimicry and metastasis, in HeLa cervical tumor cells. Inhibiting TXNDC5 expression simultaneously led to the increased expression of SERPINF1 (serpin peptidase inhibitor, clade F) and TRAF1 (TNF receptor-associated factor 1), which have been reported to inhibit angiogenesis and metastasis as well as induce apoptosis. This finding was confirmed in Caski and C-33A cervical tumor cell lines. The ability to form tube-like structures was rescued in HeLa cells simultaneously treated with anti-TXNDC5, SERPINF1 and TRAF1 siRNAs. Furthermore, the inhibition of TXNDC5 expression significantly attenuated endothelial tube formation, a marker of angiogenesis, in human umbilical vein endothelial cells. The present study suggests that TXNDC5 is a susceptibility gene in cervical cancer, and high expression of this gene contributes to abnormal angiogenesis, vasculogenic mimicry and metastasis by down-regulating SERPINF1 and TRAF1 expression.

Abstract A34: The discovery of novel noncoding circular RNAs generated by high-risk human papillomavirus type 16

Abstract Recently, two independent research teams discovered thousands of conserved non-coding human circular RNAs (circRNAs), however, there are no studies suggesting the existence of circRNAs produced by human viruses. The objective of this study is to explore our hypothesis that human papillomavirus (HPV)-16 creates viral circRNAs that may alter host activity in order to promote viral replication and induction of carcinogenesis. CircRNAs are non-coding RNAs generated by the alternative splicing of a 5' acceptor and 2' or 3' donor sites, creating a “head” to “tail” covalent junction of exonic and/or intronic regions. Although the role of circRNAs is largely unknown, studies have demonstrated several functions for circRNAs including sequestering microRNAs (miRNAs) and regulation of transcription. Recently, circRNAs have also been associated with several cancers such as colorectal, breast, and gastric cancers. Infections with high-risk HPVs, such as types 16 and 18, are responsible for the majority of cervical cancers and a subset of head and neck squamous cell carcinomas (HNSCC). HPV is a small double-stranded circular DNA encoding six early proteins (E-1, -2, -4, -5, -6, and -7) and two late proteins (L-1, -2). HPV DNA is tightly regulated and undergoes extensive and complex splicing to achieve the expression of these proteins. Our preliminary data suggest that HPV-16 extensive splicing generates at least two viral circRNAs (hpv-circRNAs) that could potentially regulate host cellular processes promoting tumorigenesis. We demonstrated the existence of the “head” to “tail” junctions of hpv-circRNAs in HPV-16 viral RNA with reverse transcription polymerase chain reaction (RT-PCR) amplification using divergent primers in RNA extracted from cervical tumor cell lines. Quantitative RT-PCR (qRT-PCR) analysis showed the retention of the hpv-circRNAs in RNase R treated samples suggesting the absence of free RNA ends in these hpv-circRNAs. Moreover, these viral circRNAs persisted even after the cervical tumor cells were exposed to Actinomycin D for 48 hrs (to inhibit RNA synthesis), confirming the stability of these hpv-circRNAs in comparison to the short-lived lariat structures that also can occur during splicing. Together, our data suggest the existence of viral circRNAs produced in HPV-16. To the best of our knowledge, these are the first described human viral generated circRNAs. Currently, we are characterizing these hpv-circRNAs by conducting knockdown and rescue experiments followed by behavior assays (e.g. invasion, angiogenesis, and proliferation). We believe this project will be significant in that it will identify and show the importance of viral circRNAs in HPV-related cancers as well as give us new information about a novel mechanism by which high-risk HPV infection contributes to cervical and HNSCC carcinogenesis. Citation Format: Karen E. Hayes, Jamie A. Barr, Jeremy E. Wilusz, Ivan Martinez. The discovery of novel noncoding circular RNAs generated by high-risk human papillomavirus type 16. [abstract]. In: Proceedings of the AACR Special Conference on Noncoding RNAs and Cancer: Mechanisms to Medicines ; 2015 Dec 4-7; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2016;76(6 Suppl):Abstract nr A34.