Human Cancer-derived Cell Lines Research Articles

Abstract PO2-04-13: TWT-203: PHASE 1b/2 STUDY OF CFI-402257 AS MONOTHERAPY IN ADVANCED SOLID TUMORS AND IN COMBINATION WITH FULVESTRANT IN PATIENTS WITH ER+/HER2- ADVANCED BREAST CANCER AFTER PROGRESSION ON PRIOR CDK4/6 INHIBITORS AND ENDOCRINE THERAPY

Abstract Background: TTK (Threonine Tyrosine Kinase also known as Monopolar spindle 1), is a dual-specificity serine-threonine kinase critical for anaphase promoting complex inhibition at the spindle assembly checkpoint and is required for chromosome alignment and error correction. TTK inhibition results in premature mitosis exiting with unattached chromosomes potentially leading to aneuploidy and cell death. High TTK tumor levels correlate with worse prognosis and contribute to the survival and proliferation of aneuploid cells. CFI-402257, a potent and selective inhibitor of TTK, inhibits the growth of a variety of human cancer-derived cell lines. A first-in-human phase 1 study of CFI-402257 (NCT02792465) demonstrated a tolerable safety profile when enrolled as a monotherapy in solid tumors, and in combination with fulvestrant in hormone receptor positive, HER2 negative (HR+/HER2-) breast cancer1. The dose for expansion was 168 mg, dose limiting toxicity was dose-dependent neutropenia which was manageable and reversible. Investigator-confirmed partial responses (cPR) were observed in 5 pts (8%) with 32 (50.8%) exhibiting disease control. In the HR+/HER2- breast cancer population previously treated with cyclin dependent kinase 4/6 inhibitors (CDK4/6i) and aromatase inhibitors (N=25), there were 4 cPR’s with a median duration of response of 223 days, with responses emerging after 2 cycles of therapy. Responses were observed with CFI-402257 as a single agent and in combination with fulvestrant. Based on these data, study TWT-203 will focus on advanced solid tumors for dose confirmation then focus on advanced HR+/HER2- breast cancers in combination with an approved endocrine therapy. Methods: In TWT-203 study, safety and clinical activity of CFI-402257 monotherapy will be evaluated in patients (pts) with advanced solid tumors (Part A) or in combination with fulvestrant in pts with HR+/HER2- advanced breast cancer (Part B). Part A will confirm the RP2D using a 3+3 design with a starting dose of 126 mg daily. Part B evaluates CFI-402257 in combination with fulvestrant in pts with HR+/HER2- advanced breast cancer following progression on prior CDK4/6i and endocrine therapy. Efficacy endpoints include overall response rate and disease control rate. Safety endpoints include incidence of treatment emergent adverse events. Exploratory objectives include characterization of protein and molecular alterations relevant to the cell cycle and CFI-402257 response. Results: At data cutoff of 11 May 2023, 14 pts were enrolled. All received monotherapy treatment. Median treatment duration was 2.1 months (range, 0.2-7.3+). Median age was 67 years (57-76). Median number of prior regimens was 3.5 (2-12). Tumor types enrolled were colorectal (n=6, 43%), breast (3, 21%), and endometrial, hepatocellular, leiomyosarcoma, pancreatic, and sarcoma (1 each, 7%). 4 dose levels, from 126 to 252 mg, were studied. Most pts (12, 86%) experienced ≥1 treatment emergent adverse event (TEAE). More than half of pts (8, 57%) experienced ≥1 treatment related TEAE. Most common TEAEs were fatigue (5, 36%) and nausea (4, 29%). 5 pts (36%) experienced TEAEs grade ≥3, most common were fatigue, neutrophil count decrease, white blood cell count decrease (2 pts each, 14.3%). 1 pt (7%) experienced a serious adverse event (hematuria), not related to study therapy. No patients discontinued treatment due to TEAE. All pts who ended treatment were due to disease progression (8, 57%). No grade 5 TEAEs occurred. No dose limiting toxicities were reported. Disease control rate (CR, PR, or SD ≥ 6 weeks from baseline) was 54.5% (6 pts/11): all achieved SD. 3 of the 6 pts remain on study. Conclusion: CFI-402257 is a potent inhibitor of TTK. It is well tolerated with manageable TEAEs, no dose limiting or treatment limiting toxicities, and no treatment related deaths. Dose expansion in the patient population of interest will commence. 1. John Hilton et al. Cancer Res 2023;83(5 Suppl): P6-10-13. Citation Format: Justin Call, Muralidhar Beeram, Alexander I. Spira, Mark Bray, Dih-Yih Chen, Long Kwei, Emily Roberts-Thomson, Trisha Denny, Roger Sidhu, Robert Wesolowski. TWT-203: PHASE 1b/2 STUDY OF CFI-402257 AS MONOTHERAPY IN ADVANCED SOLID TUMORS AND IN COMBINATION WITH FULVESTRANT IN PATIENTS WITH ER+/HER2- ADVANCED BREAST CANCER AFTER PROGRESSION ON PRIOR CDK4/6 INHIBITORS AND ENDOCRINE THERAPY [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 PO2-04-13.

Identification and bioactivity evaluation of miliusanes from Miliusa sinensis

Miliusanes are a class of anticancer lead molecules belonging to meroterpenoids with an 18-carbon skeleton isolated from Miliusa plants. A phytochemical study of the plant M. sinensis was carried out to discover new miliusanes with diverse structural features in order to better understand their structure-activity relationship. As a result, 20 compounds including 12 new ones (7–14 and 17–20) belonging to two sub-classes of miliusanes were isolated and identified from the twigs and leaves of this plant. Their structures, including absolute configurations, were determined by spectroscopic analyses and electronic circular dichroism. The absolute stereochemistry of miliusane structures has also been confirmed for the first time through the single crystal X-ray diffraction analysis of miliusol (1). Bioactivity evaluation showed that some of the miliusane isolates potently inhibit cell growth of several human derived cancer cell lines with IC50 values ranging from 0.52 to 23.5 μM. Compound 11 demonstrated more potent cytotoxic activity than the known miliusol (1) in stomach cancer cells though its structure contains an unconjugated 1, 4-diketone system, which added a new structure-activity feature to miliusanes. The preliminary mechanism of action studies revealed that they could be a class of dual cell migration inhibitor and senescence inducer.

Acss2/HIF-2 signaling facilitates colon cancer growth and metastasis.

The microenvironment of solid tumors is characterized by oxygen and glucose deprivation. Acss2/HIF-2 signaling coordinates essential genetic regulators including acetate-dependent acetyl CoA synthetase 2 (Acss2), Creb binding protein (Cbp), Sirtuin 1 (Sirt1), and Hypoxia Inducible Factor 2α (HIF-2α). We previously shown in mice that exogenous acetate augments growth and metastasis of flank tumors derived from fibrosarcoma-derived HT1080 cells in an Acss2/HIF-2 dependent manner. Colonic epithelial cells are exposed to the highest acetate levels in the body. We reasoned that colon cancer cells, like fibrosarcoma cells, may respond to acetate in a pro-growth manner. In this study, we examine the role of Acss2/HIF-2 signaling in colon cancer. We find that Acss2/HIF-2 signaling is activated by oxygen or glucose deprivation in two human colon cancer-derived cell lines, HCT116 and HT29, and is crucial for colony formation, migration, and invasion in cell culture studies. Flank tumors derived from HCT116 and HT29 cells exhibit augmented growth in mice when supplemented with exogenous acetate in an Acss2/HIF-2 dependent manner. Finally, Acss2 in human colon cancer samples is most frequently localized in the nucleus, consistent with it having a signaling role. Targeted inhibition of Acss2/HIF-2 signaling may have synergistic effects for some colon cancer patients.

N-Hydroxy-Phe-Phe, a new dipeptide, and cytotoxic macrocyclic trichothecenes from the lethal toxic mushroom Podostroma cornu-damae.

Podostroma cornu-damae, commonly referred to as the red deer's horn mushroom due to its distinct resemblance to the antlers of a deer, is a lethal toxic mushroom that causes vomiting, dehydration, diarrhea, disturbance of consciousness, and even death. In continuation of our research aiming to investigate the novel structural and/or biological principles present in Korean wild mushrooms, a new N-hydroxyphenylalanine-phenylalanine dipeptide, N-hydroxy-Phe-Phe (1), and three known macrocyclic trichothecenes, satratoxin H (2), 12'-episatratoxin H (3), and roridin F (4), were isolated from the MeOH extract of a plate culture of the poisonous mushroom P. cornu-damae. The chemical structure of the new dipeptide (1) was determined by analyzing 1D and 2D NMR spectra and high-resolution (HR)-electrospray ionization mass spectroscopy (ESIMS), along with a computational method combined with a statistical procedure (DP4+), and its absolute configuration was unambiguously assigned by quantum chemical ECD calculations. To the best of our knowledge, compound 1 is the first dipeptide found in P. cornu-damae. Upon evaluating the cytotoxicity of compounds 1-4 against four human-derived cancer cell lines namely SK-OV-3, SK-MEL-2, A549, and HCT15, 12'-episatratoxin H (3) displayed potent cytotoxic effects toward all four cell lines tested, with IC50 values ranging from 0.7 to 2.8 nM, which was found to be stronger than that of doxorubicin. Satratoxin H (2) also demonstrated moderate cytotoxic potency against all four cell lines, with IC50 values ranging from 1.93 to 4.22 μM. Our findings provide experimental data supporting the potential of the poisonous mushroom P. cornu-damae as a source of anticancer agents.

In Vitro Cytotoxic Evaluation of a Silver(I) Complex Including Non-Steroidal Anti-Inflammatory Drug Niflumic Acid and 3-Picoline on Human-Derived Cancer Cell Lines

Burada, steroidal olmayan anti-enflamatuar ilaç niflumik asit ve 3-pikolin içeren yeni bir gümüş(I) kompleksi sentezlendi ve FT-IR, 1H NMR, elemental ve termik analiz teknikleri ile karakterize edildi. Bu teknikler, sentezlenen kompleksin formülünün [Ag(nif)(3-pic)] olduğunu gösterdi. Kompleks, ligand (niflumik asit) ve gümüş iyonlarının tek başına sitotoksik yeteneği, insan meme adenokarsinomu (MDA-MB-453), akciğer adenokarsinomu (A-549), kolorektal adenokarsinom (HT-29) ve fare fibroblast hücre hatlarına (3T3-L1) karşı test edildi. XTT sonuçları, AgNO3 ve niflumik asidin tek başına kanser ve sağlıklı hücre hatları üzerinde orta düzeyde sitotoksisite sergilemesine rağmen, kompleksin kanser hücreleri üzerinde doza bağlı bir şekilde güçlü sitotoksik aktivite gösterdiğini gösterdi. Kompleksin en güçlü sitotoksisitesi ve en yüksek seçiciliği HT-29 hücrelerinde belirlendi. Bu bulgular, gelişmiş antikanser çalışmalarında yeni gümüş(I) kompleksinin değerlendirilmesi için temel çıktılar sağlar.

Involvement of abnormal dystroglycan expression and matriglycan levels in cancer pathogenesis.

Dystroglycan (DG) is a glycoprotein composed of two subunits that remain non-covalently bound at the plasma membrane: α-DG, which is extracellular and heavily O-mannosyl glycosylated, and β-DG, an integral transmembrane polypeptide. α-DG is involvedin the maintenance of tissue integrity and function in the adult, providing an O-glycosylation-dependent link for cells to their extracellular matrix. β-DG in turn contacts the cytoskeleton via dystrophin and participates in a variety of pathways transmitting extracellular signals to the nucleus.Increasing evidence exists of a pivotal role of DG in the modulation of normal cellular proliferation. In this context, deficiencies in DG glycosylation levels, in particular those affecting the so-called matriglycan structure, have been found in an ample variety of human tumors and cancer-derived cell lines. This occurs together with an underexpression of the DAG1 mRNA and/or its α-DG (core) polypeptide product or, more frequently, with a downregulation of β-DG protein levels. These changes are in general accompanied in tumor cells by a low expression of genes involved in the last steps of the α-DG O-mannosyl glycosylation pathway, namely POMT1/2, POMGNT2, CRPPA, B4GAT1 and LARGE1/2. On the other hand, a series of other genes acting earlier in this pathway are overexpressed in tumor cells, namely DOLK, DPM1/2/3, POMGNT1, B3GALNT2, POMK and FKTN, hence exerting instead a pro-oncogenic role. Finally, downregulation of β-DG, altered β-DG processing and/or impaired β-DG nuclear levels are increasingly found in human tumors and cell lines. It follows that DG itself, particular genes/proteins involved in its glycosylation and/or their interactors in the cell could be useful as biomarkers of certain types of human cancer, and/or as molecular targets of new therapies addressing these neoplasms.

Therapeutic Potential of 5'-Methylschweinfurthin G in Merkel Cell Polyomavirus-Positive Merkel Cell Carcinoma.

Merkel cell carcinoma (MCC) is a rare but aggressive form of skin cancer predominantly caused by the human Merkel cell polyomavirus (MCPyV). Treatment for MCC includes excision and radiotherapy of local disease, and chemotherapy or immunotherapy for metastatic disease. The schweinfurthin family of natural compounds previously displayed potent and selective growth inhibitory activity against the NCI-60 panel of human-derived cancer cell lines. Here, we investigated the impact of schweinfurthin on human MCC cell lines. Treatment with the schweinfurthin analog, 5′-methylschweinfurth G (MeSG also known as TTI-3114), impaired metabolic activity through induction of an apoptotic pathway. MeSG also selectively inhibited PI3K/AKT and MAPK/ERK pathways in the MCPyV-positive MCC cell line, MS-1. Interestingly, expression of the MCPyV small T (sT) oncogene selectively sensitizes mouse embryonic fibroblasts to MeSG. These results suggest that the schweinfurthin family of compounds display promising potential as a novel therapeutic option for virus-induced MCCs.

ATM Pathway Is Essential for HPV-Positive Human Cervical Cancer-Derived Cell Lines Viability and Proliferation.

Infection with some mucosal human papillomavirus (HPV) types is the etiological cause of cervical cancer and of a significant fraction of vaginal, vulvar, anal, penile, and head and neck carcinomas. DNA repair machinery is essential for both HPV replication and tumor cells survival suggesting that cellular DNA repair machinery may play a dual role in HPV biology and pathogenesis. Here, we silenced genes involved in DNA Repair pathways to identify genes that are essential for the survival of HPV-transformed cells. We identified that inhibition of the ATM/CHK2/BRCA1 axis selectively affects the proliferation of cervical cancer-derived cell lines, without altering normal primary human keratinocytes (PHK) growth. Silencing or chemical inhibition of ATM/CHK2 reduced the clonogenic and proliferative capacity of cervical cancer-derived cells. Using PHK transduced with HPV16 oncogenes we observed that the effect of ATM/CHK2 silencing depends on the expression of the oncogene E6 and on its ability to induce p53 degradation. Our results show that inhibition of components of the ATM/CHK2 signaling axis reduces p53-deficient cells proliferation potential, suggesting the existence of a synthetic lethal association between CHK2 and p53. Altogether, we present evidence that synthetic lethality using ATM/CHK2 inhibitors can be exploited to treat cervical cancer and other HPV-associated tumors.

TWT-203: Phase 1b/2 dose-confirming study of CFI-402257 as a single agent in advanced solid tumors and in combination with fulvestrant in patients with ER+/HER2- advanced breast cancer after disease progression on prior CDK4/6 and endocrine therapy.

TPS1123 Background: TTK (Threonine Tyrosine Kinase also known as Monopolar spindle 1 [Mps1]), is a dual-specificity serine-threonine kinase critical for anaphase promoting complex/cyclosome inhibition at the spindle assembly checkpoint, and is required for chromosome alignment and error correction. Inhibition of TTK causes cells to prematurely exit mitosis with unattached chromosomes, resulting in aneuploidy and cell death. Higher TTK tumor levels correlate with worse prognosis and may contribute to the survival and proliferation of aneuploid cells. CFI-402257, a potent and selective inhibitor of TTK inhibits the growth of a variety of human cancer-derived cell lines with IC50 of 8-40 nM. A first-in-human phase 1 study of CFI-402257 administered orally as a single agent, demonstrated a tolerable safety profile and evidence of clinical activity in patients with advanced solid tumors. The MTD was 168 mg daily, and the study expanded to 3 cohorts: solid tumors, HER2-negative breast cancer, and hormone receptor positive (HR+/HER2-) breast cancer in combination with fulvestrant. The dose limiting toxicity was manageable and reversible dose-dependent neutropenia. Investigator-confirmed partial responses (cPR) were observed in 5 patients (10.6%) with 25 (53.2%) exhibiting disease control. In the HR+/HER2- breast cancer population previously treated with cyclin dependent kinase 4/6 inhibitors (CDK4/6i) and aromatase inhibitors, there were 4 cPR’s with a median duration of response of 256 days, with responses emerging after 2 cycles of therapy. Responses were observed with CFI-402257 as a single agent and in combination with fulvestrant. Based on these data, study TWT-203 will focus on advanced solid tumors and advanced HR+/HER2- breast cancers in combination with an approved endocrine therapy. Methods: Safety and clinical activity of CFI-402257 monotherapy will be evaluated in patients with advanced solid tumors (Part A) or in combination with fulvestrant in patients with HR+/HER2- advanced breast cancer (Part B). Part A will confirm the RP2D using a 3+3 design with a starting dose of 126 mg daily. Part B evaluates CFI-402257 in combination with fulvestrant in patients with HR+/HER2- advanced breast cancer following progression on prior CDK4/6i and endocrine therapy. Initially 6 patients will be treated with CFI-402257 and fulvestrant, and safety, tolerability, and PK evaluated, with further expansion to confirm the RP2D and characterize CFI-402257 activity. Efficacy endpoints include overall response rate and disease control rate. Safety endpoints include incidence of treatment emergent adverse events. Exploratory objectives include characterization of protein and molecular alterations relevant to the cell cycle and CFI-402257 response.

Engineering Cancer/Testis Antigens With Reversible S-Cationization to Evaluate Antigen Spreading

Serum autoantibody to cancer/testis antigens (CTAs) is a critical biomarker that reflects the antitumor immune response. Quantitative and multiplexed anti-CTA detection arrays can assess the immune status in tumors and monitor therapy-induced antitumor immune reactions. Most full-length recombinant CTA proteins tend to aggregate. Cysteine residue-specific S-cationization techniques facilitate the preparation of water-soluble and full-length CTAs. Combined with Luminex technology, we designed a multiple S-cationized antigen-immobilized bead array (MUSCAT) assay system to evaluate multiple serum antibodies to CTAs. Reducible S-alkyl-disulfide-cationized antigens in cytosolic conditions were employed to develop rabbit polyclonal antibodies as positive controls. These control antibodies sensitively detected immobilized antigens on beads and endogenous antigens in human lung cancer-derived cell lines. Rabbit polyclonal antibodies successfully confirmed the dynamic ranges and quantitative MUSCAT assay results. An immune monitoring study was conducted using the serum samples on an adenovirus−mediated REIC/Dkk−3 gene therapy clinical trial that showed a successful clinical response in metastatic castration-resistant prostate cancer. Autoantibody responses were closely related to clinical outcomes. Notably, upregulation of anti-CTA responses was monitored before tumor regression. Thus, quantitative monitoring of anti-CTA antibody biomarkers can be used to evaluate the cancer-immunity cycle. A quality-certified serum autoantibody monitoring system is a powerful tool for developing and evaluating cancer immunotherapy.

The phytochemical, corynoline, diminishes Aurora kinase B activity to induce mitotic defect and polyploidy

Plants are a rich source for bioactive compounds. However, plant extracts can harbor a mixture of bioactive molecules that promote divergent phenotypes and potentially have confounding effects in bioassays. Even with further purification and identification, target deconvolution can be challenging. Corynoline and acetylcorynoline, are phytochemicals that were previously isolated through a screen for compounds able to induce mitotic arrest and polyploidy in oncogene expressing retinal pigment epithelial (RPE) cells. Here, we shed light on the mechanism by which these phytochemicals can attack human cancer cells. Mitotic arrest was coincident to the induction of centrosome amplification and declustering, causing multi-polar spindle formation. Corynoline was demonstrated to have true centrosome declustering activity in a model where A549 cells were chemically induced to have more than a regular complement of centrosomes. Corynoline could inhibit the centrosome clustering required for pseudo-bipolar spindle formation in these cells. The activity of AURKB, but not AURKA or polo-like kinase 4, was diminished by corynoline. It only partially inhibited AURKB, so it may be a partial antagonist or corynoline may work upstream on an unknown regulator of AURKB activity or localization. Nonetheless, corynoline and acetylcorynoline inhibited the viability of a variety of human cancer derived cell lines. These phytochemicals could serve as prototypes for a next-generation analog with improved potency, selectivity or in vivo bioavailability. Such an analog could be useful as a non-toxic component of combination therapies where inhibiting the chromosomal passenger protein complex is desired.

The enzyme subunit SubA of Shiga toxin-producing E. coli strains demonstrates comparable intracellular transport and cytotoxic activity as the holotoxin SubAB in HeLa and HCT116 cells in vitro

The subtilase cytotoxin (SubAB) is secreted by certain Shiga toxin-producing Escherichia coli (STEC) strains and is composed of the enzymatically active subunit SubA and the pentameric binding/transport subunit SubB. We previously demonstrated that SubA (10 µg/ml), in the absence of SubB, binds and intoxicates the human cervix cancer-derived epithelial cell line HeLa. However, the cellular and molecular mechanisms underlying the cytotoxic activity of SubA in the absence of SubB remained unclear. In the present study, the cytotoxic effects mediated by SubA alone were investigated in more detail in HeLa cells and the human colon cancer cell line HCT116. We found that in the absence of SubB, SubA (10 µg/ml) is internalized into the endoplasmic reticulum (ER), where it cleaves the chaperone GRP78, an already known substrate for SubA after its canonical uptake into cells via SubB. The autonomous cellular uptake of SubA and subsequent cleavage of GRP78 in cells is prevented by treatment of cells with 10 µM brefeldin A, which inhibits the transport of protein toxins into the ER. In addition, by analyzing the SubA mutant SubAΔC344, we identified the C-terminal SEEL motif as an ER-targeting signal. Conclusively, our results strongly suggest that SubA alone shares the same intracellular transport route and cytotoxic activity as the SubAB holotoxin.

Combination of Camidanlumab Tesirine, a CD25-Targeted ADC, with Gemcitabine Elicits Synergistic Anti-Tumor Activity in Preclinical Tumor Models

Camidanlumab tesirine (ADCT-301) is an antibody-drug conjugate (ADC) comprised of HuMax®-TAC, a monoclonal antibody directed against human CD25, conjugated to the pyrrolobenzodiazepine dimer payload tesirine[1]. Currently, camidanlumab tesirine is being evaluated in a pivotal Phase 2 clinical trial in patients with relapsed or refractory Hodgkin lymphoma (HL) (NCT04052997) and in a Phase 1b clinical trial in patients with advanced solid tumors (NCT03621982). In pre-clinical studies, camidanlumab tesirine demonstrated strong and durable single agent activity in CD25-expressing lymphoma xenograft models[1] and in vitro it synergised with selected targeted agents[2]. Moreover, CD25-ADC, a mouse CD25 cross-reactive surrogate of camidanlumab tesirine, induced potent anti-tumor immunity against established syngeneic solid tumor models by depleting CD25-positive tumor-infiltrating T regulatory cells (Tregs) and it showed synergistic activity when combined with PD-1 blockade[3]. Here, we investigated the in vitro and in vivo anti-tumor activity of camidanlumab tesirine combined with gemcitabine, a common standard-of-care chemotherapeutic agent used both in a hematological and solid tumor clinical setting. In vitro, the combination of camidanlumab tesirine and gemcitabine was evaluated in three human-derived cancer cell lines (two HL and one anaplastic large cell lymphoma, ALCL) and resulted in synergistic activity as determined by the Chou-Talalay method. In vivo, camidanlumab tesirine was tested either alone (0.05 or 0.1 mg/kg, single dose) or in combination with gemcitabine (80 mg/kg, q3dx4) in the CD25-expressing ALCL Karpas299 xenograft model. At both ADC dose levels, combination with gemcitabine resulted in synergistic anti-tumor activity (coefficient of drug interaction (CDI) 0.51 and 0.17, respectively), better response rates and increased survival compared to monotherapy with camidanlumab tesirine. In order to extend the investigation to solid tumor models, CD25-ADC was tested in the CT26 syngeneic model, a colorectal cancer model with CD25-expressing tumor-infiltrating Tregs. CD25-ADC was administered either alone (0.1, 0.5 or 1 mg/kg, single dose) or in combination with gemcitabine (80 mg/kg, q3dx4). At the 0.1 mg/kg dose of CD25-ADC, combination with gemcitabine resulted in synergistic anti-tumor activity (CDI 0.68). Moreover, at 0.5 and 1 mg/kg, the combination of CD25-ADC and gemcitabine resulted in more durable anti-tumor activity and better response rates compared to both monotherapy treatments. In conclusion, the combination of camidanlumab tesirine and gemcitabine was synergistic both in vitro and in vivo in lymphoma preclinical models. Synergistic anti-tumor activity was also demonstrated in a colorectal cancer model using CD25-ADC, a mouse-cross-reactive version of camidanlumab tesirine, in combination with gemcitabine. Altogether, these novel pre-clinical data warrant translation of the combination between camidanlumab tesirine and gemcitabine into the clinic. 1.Flynn, M.J., et al., ADCT-301, a Pyrrolobenzodiazepine (PBD) Dimer-Containing Antibody-Drug Conjugate (ADC) Targeting CD25-Expressing Hematological Malignancies. Mol Cancer Ther, 2016. 15(11): p. 2709-2721. 2.Spriano, F., et al., The anti-CD25 antibody-drug conjugate camidanlumab tesirine (ADCT-301) presents a strong preclinical activity both as single agent and in combination in lymphoma cell lines. Hematological Oncology, 2019. 37(S2): p. 323-324. 3.Zammarchi, F., et al., A CD25-targeted antibody-drug conjugate depletes regulatory T cells and eliminates established syngeneic tumors via antitumor immunity. Journal for ImmunoTherapy of Cancer, 2020. In press. Disclosures Jabeen: ADC Therapeutics: Current Employment. Hartley:ADC Therapeutics: Consultancy, Current equity holder in publicly-traded company, Research Funding. Van Berkel:ADC-Therapeutics: Current Employment, Current equity holder in publicly-traded company. Zammarchi:ADC-Therapeutics: Current Employment, Current equity holder in publicly-traded company.

Selective photodynamic effects on cervical cancer cells provided by P123 Pluronic®-based nanoparticles modulating hypericin delivery

At present, cervical cancer is the fourth leading cause of cancer among women worldwide with no effective treatment options. In this study we aimed to evaluate the efficacy of hypericin (HYP) encapsulated on Pluronic® P123 (HYP/P123) photodynamic therapy (PDT) in a comprehensive panel of human cervical cancer-derived cell lines, including HeLa (HPV 18-positive), SiHa (HPV 16-positive), CaSki (HPV 16 and 18-positive), and C33A (HPV-negative), compared to a nontumorigenic human epithelial cell line (HaCaT). Were investigated: (i) cell cytotoxicity and phototoxicity, cellular uptake and subcellular distribution; (ii) cell death pathway and cellular oxidative stress; (iii) migration and invasion. Our results showed that HYP/P123 micelles had effective and selective time- and dose-dependent phototoxic effects on cervical cancer cells but not in HaCaT. Moreover, HYP/P123 micelles accumulated in endoplasmic reticulum, mitochondria and lysosomes, resulting in photodynamic cell death mainly by necrosis. HYP/P123 induced cellular oxidative stress mainly via type II mechanism of PDT and inhibited cancer cell migration and invasion mainly via MMP-2 inhibition. Taken together, our results indicate a potentially useful role of HYP/P123 micelles as a platform for HYP delivery to more specifically and effectively treat cervical cancers through PDT, suggesting they are worthy for in vivo preclinical evaluations.

In vitro and in vivo anticancer efficacy of Adiantum capillus-veneris L. against some selected human cancer cell lines and on EAC mouse model

Adiantum capillus-veneris, commonly known as maidenhair fern belongs to family Pteridaceae, has traditionally been used in various medicinal preparations as demulcent, expectorant, emmenagogue, diuretic etc. in the form of oil, paste, decoction and powder. It has also prominent role in hair growing and has anti-microbial, anti-inflammatory, anti-diabetic, anti-nociceptive and antioxidant properties of therapeutic interest. This study aimed to investigate the in vitro cytotoxic activity of fractions of ethanolic extract isolated from the aerial part of A. capillus-veneris against some human cancer cell lines such as colon (HCT-116), lung (A549), breast (MCF-7) and pancreatic (MIA PaCa-2) and tumor cell proliferation/inhibition was assessed using MTT assay. The in vivo anticancer activity of hexane fraction was also evaluated against murine Ehrlich ascites carcinoma (EAC) model. The results confirmed that all the fractions of ethanolic extract exhibited promising in vitro inhibition of tumor cell proliferation when tested against different human cancer cell lines. Among all, hexane fraction proved to be more effective having IC50 values 21.72, 22.67, 26.25 μg/mL, for HCT- 116, A-549, MCF-7, respectively, but chloroform fraction revealed to be more cytotoxic against Mia-PACA-2 having IC50 value 14.72 μg/mL. Higher cytotoxic activity is found to be associated with lower IC50 values. The findings showed that all five fractions exhibited dose-dependent killing capabilities in various human derived cancer cell lines at 48 h of treatment. Hexane fraction was found to inhibit tumour growth development by 16.95%, 41.12% and 82.07% at 50, 100 and 200 mg/kg body weight, respectively. Additionally, this fraction was predicted to be non-toxic at the tested doses. The findings indicate that A. capillus-veneris herb is an antineoplastic agent and suggest that further studies evaluating the isolation of active antitumor compounds from A. capillus-veneris and their mechanism(s) of action are necessary.

Synthesis and characterization of (Ru(II), Co(III)) heterobimetallic complexes formed with a 1,10-phenanthroline based hydroxamic acid conjugate

A novel ambidentate type hydroxamic acid derivative (phenhaH, 1) containing an (O,O) and a 1,10-phenantroline (phen) based (N,N) donoratom set together with its heterobimetallic complexes incorporating an octahedral [Co(4 N)]3+ (4 N = tris(2-aminoethyl)amine (tren) or tris(2-methylpyridyl)amine (tpa)) and a half-sandwich type [(η6-p-cym)Ru]2+ entity have been synthesized and characterized using various analytical techniques. Reaction of [Co(4 N)Cl]Cl2 with 1 proved the exclusive (O,O) coordination of the ligand to the [Co(4 N)]3+ core to yield [Co(tpa)(phenha)](ClO4)2, (2). Subsequent treatment of 1 with [Ru(η6-p-cym)Cl2]2 and [Co(4 N)Cl]Cl2 in a one-pot reaction resulted in the formation of [(η6-p-cym)Ru(Cl)(phenha)Co(tren)]Cl(PF6)2 (3) and [(η6-p-cym)Ru(Cl)(phenha)Co(tpa)](PF6)3 (4) in which the organometallic Ru core is coordinated by the phen part while the Co entity by the hydroxamate part of 1. Cyclic voltammetry revealed that 4 could be reduced at a less negative potential and exhibits a reversible Co(III)/Co(II) redox process compared to 3 due to the π-back bonding interaction between the Co(III) centre and the pyridyl-N donors of tpa in 4. Complexes 2–4 were tested for their in vitro cytotoxicity using human-derived cancer cell lines (HeLa, MCF-7, HCT116 and MDA-MB-231) and showed moderate anti-proliferative activity in the double digit micromolar concentration range, 4 being the most active. Complex 4 displayed better activity against MDA-MB-231 cells than cisplatin.

FOXE1 regulates migration and invasion in thyroid cancer cells and targets ZEB1.

FOXE1 is a thyroid-specific transcription factor essential for thyroid gland development and maintenance of the differentiated state. Interestingly, a strong association has been recently described between FOXE1 expression and susceptibility to thyroid cancer, but little is known about the mechanisms underlying FOXE1-induced thyroid tumorigenesis. Here, we used a panel of human thyroid cancer-derived cell lines covering the spectrum of thyroid cancer phenotypes to examine FOXE1 expression and to test for correlations between FOXE1 expression, the allele frequency of two SNPs and a length polymorphism in or near the FOXE1 locus associated with cancer susceptibility, and the migration ability of thyroid cancer cell lines. Results showed that FOXE1 expression correlated with differentiation status according to histological sub-type, but not with SNP genotype or cell migration ability. However, loss-and-gain-of-function experiments revealed that FOXE1 modulates cell migration, suggesting a role in epithelial-to-mesenchymal transition (EMT). Our previous genome-wide expression analysis identified Zeb1, a major EMT inducer, as a putative Foxe1 target gene. Indeed, gene silencing of FOXE1 decreased ZEB1 expression, whereas its overexpression increased ZEB1 transcriptional activity. FOXE1 was found to directly interact with the ZEB1 promoter. Lastly, ZEB1 silencing decreased the ability of thyroid tumoral cells to migrate and invade, pointing to its importance in thyroid tumor mestastases. In conclusion, we have identified ZEB1 as a bona fide target of FOXE1 in thyroid cancer cells, which provides new insights into the role of FOXE1 in regulating cell migration and invasion in thyroid cancer.

New Dihydroisocoumarin Root Growth Inhibitors From the Sponge-Derived Fungus Aspergillus sp. NBUF87.

Six new dihydroisocoumarins, aspergimarins A−F (1−6), were discovered together with five known analogs (7−11) from a monoculture of the sponge-derived fungus Aspergillus sp. NBUF87. The structures of these compounds were elucidated through comprehensive spectroscopic methods, and absolute configurations were assigned after X-ray crystallography, use of the modified Mosher’s method, and comparison of electronic circular dichroism (ECD) data with literature values for previously reported analogs. Compounds 1−11 were evaluated in a variety of bioassays, and at 100 μM, both 1 and 5 showed significant inhibitory effects on the lateral root growth of Arabidopsis thaliana Columbia-0 (Col-0). Moreover, at 100 μM, 5 also possessed notable inhibition against the primary root growth of Col-0. Meanwhile, 1−11 were all found to be inactive in vitro against acetylcholinesterase (AChE) (IC50 > 100 μM), four different types of human-derived cancer cell lines (IC50 > 50 μM), as well as methicillin-resistant Staphylococcus aureus and Escherichia coli (MIC > 50 μg/mL), and Plasmodium falciparum W2 (EC50 > 100 μg/mL), in phenotypic tests.

Antiproliferative and antiviral activity of methanolic extracts from Sardinian Maltese Mushroom (Cynomorium coccineum L.)

Cynomorium coccineum is a non-photosynthetic plant that grows in Mediterranean countries and that is amply used in the traditional medicine. The aim of this study was to extend previous studies on the chemical and biological properties of C. coccineum, evaluating the potential antiviral and antiproliferative activity of the methanolic extract. The MTT assay was used for the in vitro cytotoxic studies against human cancer-derived cell lines, while both MTT and plaque reduction (PRT) methods were used to evaluate the potential inhibitory effect of the extract against a panel of mammal viruses. The results obtained showed no selective activity against any DNA and RNA virus but revealed an interesting antiproliferative activity against human leukaemia-derived cell lines.

Silver(I) complexes containing diclofenac and niflumic acid induce apoptosis in human-derived cancer cell lines

We investigated the anti-cancer activity of [Ag(μ-dicl)] n 1 and [AgH(nif)2] 2 complexes against human cancer cell lines (MCF-7, HT-29, and HepG2) and mouse fibroblast (3T3-L1) cell line. Anti-proliferative activity was monitored by XTT cell viability and LDH leakage assays. Cell death mode was evaluated by multi-caspase activity, annexin V cytofluorimetric, MMP, cell cycle arrest, and ROS generation assays. Antioxidant capacity was evaluated on SOD, GPx, GR, and CAT enzymes. The XTT and LDH assay results showed that both complexes exhibited strong cytotoxicity against the tested cancer cell lines. The apoptotic mechanisms of the complexes were demonstrated by loss of MMP and increase in phosphatidylserine translocation, sub-G1 phase, and multi-caspase activity. Besides, both complexes induced the oxidative stress in MCF-7 cells by decreasing the activity of GPx, GR, and CAT enzymes. In conclusion, both Ag(I) complexes, especially 1, warrant for further in vivo evaluation as a new alternative in cancer treatment. Highlights Ag(I) complexes inhibited cell proliferation and induced LDH leakage in human cancer cell lines. Ag(I) complexes induced apoptosis through MMP disruption and ROS generation. Ag(I) complexes mimicked the multi-caspase activity. Ag(I) complexes increased the accumulation of sub-G1 phase. Ag(I) complexes inhibited the activity of antioxidant system enzymes.