Vascular endothelial growth factor-C in activating vascular endothelial growth factor receptor-3 and chemokine receptor-4 in melanoma adhesion

Vascular endothelial growth factor-C (VEGF-C) binds to receptor vascular endothelial growth factor receptor-3 (VEGFR-3) expressed on lymphatic endothelial and melanoma cells. Binding of VEGF-C to VEGFR-3 enhances receptor phosphorylation that activates mitogen-activated protein kinase (MAP-K) and phosphatidylinositol-3-kinase (PI3K). These signalling pathways regulate cell migration and adhesion in response to internal or external changes. In addition, the overexpression of VEGF-C upregulates chemokine receptor CXCR-4 in tumours (melanoma). CXCR-4 is expressed on cells of the immune system (natural killer cells) and facilitates the migration of leukocytes in response to the CXCL12 ligand. The latter is expressed by lymphatic endothelial cells and by stromal cells in the tumour microenvironment (TME). The gradient established between CXCR-4 expressed on tumour cells and CXCL12 produced by stromal and lymphatic endothelial cells enhances tumour cell metastasis. 3-(4-Dimethylamino-naphthalen-1-ylmethylene)-1, 3-dihydroindol-2-one, MAZ-51, is an indolinone-based synthetic molecule that inhibits the phosphorylation of the tyrosine kinase receptor VEGFR-3. CTCE-9908, a CXCR-4 antagonist derived from human CXCL12, hinders receptor phosphorylation and the subsequent signalling pathways that would be activated. VEGF-C is stimulated by transforming growth factor-beta 1 (TGF-β1), which facilitates cell–cell and cell-matrix adhesion by regulating cadherins through the activation of focal adhesion kinase (FAK) and mediates paxillin upregulation. Increased VEGF-C protein levels stimulated by TGF-β bound to VEGFR-3 impact on intracellular pathways that promote tumour cell adhesion. In addition, increased VEGF-C protein levels lead to enhanced CXCR-4 protein expression. Therefore, effective blocking of VEGR-3 and CXCR-4 may inhibit tumour cell metastasis by hampering intracellular proteins promoting adhesion.The Association of African Universities (AAU), the National Research Foundation (NRF) of South Africa, the School of Medicine Research Committee, the Faculty of Health Sciences, small grants programme and PhD completion funding scheme at the University of Pretoria, Pretoria, South Africa.http://wileyonlinelibrary.com/journal/jcmmhj2023Physiolog

In vitro effects of papaverine on cell migration and vascular endothelial growth factor in cancer cell lines

Papaverine (PPV) is a benzylisoquinoline alkaloid isolated from Papaver somniferum that exerts antiproliferative activity. However, several questions remain regarding the biochemical pathways affected by PPV in tumourigenic cells. In this study, the influence of PPV on cell migration (light microscopy), expression of vascular endothelial growth factor (VEGF) B, VEGF R1, VEGF R2, and phosphorylated focal adhesion kinase (pFAK) were investigated using spectrophotometry in MDA-MB-231-, A549- and DU145 cell lines. The migration assay revealed that, after 48 h, PPV (100 µM) reduced cell migration to 81%, 91%, and 71% in MDA-MB-231-, A549-, and DU145 cells, respectively. VEGF B expression was reduced to 0.79-, 0.71-, and 0.73-fold after 48 h of exposure to PPV in MDA-MB-231-, A549- and DU145 cells, while PPV exposure of 48 h increased VEGF R1 expression in MDA-MB-231- and DU145 cells to 1.38 and 1.46. A fold decrease in VEGF R1 expression was observed in A549 cells to 0.90 after exposure to 150 µM. No statistically significant effects were observed on VEGF R2- and FAK expression after exposure to PPV. This study contributes to the understanding of the effects of a phytomedicinal alkaloid compound in cancer cells and may provide novel approaches to the application of non-addictive alkaloids.The Cancer Association of South Africa, Medical Research Council, the Struwig Germeshuysen Trust, School of Medicine Research Committee of the University of Pretoria and the South African National Research Foundation.https://www.mdpi.com/journal/ijerphPhysiolog

Molecular farming of pembrolizumab and nivolumab

DATA AVAILABILITY STATEMENT : Data is contained within the article.Immune checkpoint inhibitors (ICIs) are a class of immunotherapy agents capable of alleviating the immunosuppressive effects exerted by tumorigenic cells. The programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) immune checkpoint is one of the most ubiquitous checkpoints utilized by tumorigenic cells for immune evasion by inducing apoptosis and inhibiting the proliferation and cytokine production of T lymphocytes. Currently, the most frequently used ICIs targeting the PD-1/PD-L1 checkpoint include monoclonal antibodies (mAbs) pembrolizumab and nivolumab that bind to PD-1 on T lymphocytes and inhibit interaction with PD-L1 on tumorigenic cells. However, pembrolizumab and nivolumab are costly, and thus their accessibility is limited in low- and middle-income countries (LMICs). Therefore, it is essential to develop novel biomanufacturing platforms capable of reducing the cost of these two therapies. Molecular farming is one such platform utilizing plants for mAb production, and it has been demonstrated to be a rapid, low-cost, and scalable platform that can be potentially implemented in LMICs to diminish the exorbitant prices, ultimately leading to a significant reduction in cancer-related mortalities within these countries.The Cancer Association of South Africa, the Medical Research Council, the Struwig Germeshuysen Trust School of Medicine Research Committee of the University of Pretoria and the South African National Research Foundation.https://www.mdpi.com/journal/ijmsPhysiologySDG-03:Good heatlh and well-bein

Sulphamoylated estradiol analogue induces reactive oxygen species generation to exert its antiproliferative activity in breast cancer cell lines

2-Methoxyestradiol (2ME), a 17β-estradiol metabolite, exerts anticancer properties in vitro and in vivo. To address 2ME’s low bioavailability, research led to the in silico design of sulphamoylated 2ME analogues. However, the role of oxidative stress induced in the activity exerted by sulphamoylated compounds remains elusive. In the current study, the influence of 2-Ethyl-17-oxoestra-1,3,5(10)-trien-3-yl sulphamate (ESE-one) on reactive oxygen species (ROS) induction and its effect on cell proliferation, as well as morphology, were assessed in breast tumorigenic cells (MCF-7 and MDA-MB-231). Fluorescent microscopy showed that sulphamoylated estradiol analogues induced hydrogen peroxide and superoxide anion, correlating with decreased cell growth demonstrated by spectrophotometry data. ESE-one exposure resulted in antiproliferation which was repressed by tiron (superoxide inhibitor), trolox (peroxyl inhibitor) and N,N0 -dimethylthiourea (DMTU) (hydrogen peroxide inhibitor). Morphological studies demonstrated that tiron, trolox and DMTU significantly decreased the number of rounded cells and shrunken cells in MCF-7 and MDA-MB-231 cells induced by ESE-one. This in vitro study suggests that ESE-one induces growth inhibition and cell rounding by production of superoxide anion, peroxyl radical and hydrogen peroxide. Identification of these biological changes in cancer cells caused by sulphamoylated compounds hugely contributes towards improvement of anticancer strategies and the ROS-dependent cell death pathways in tumorigenic breast cells.Cancer Association of South Africa, Medical Research Council, Struwig Germeshuysen Trust, School of Medicine Research Committee of the University of Pretoria, South African National Research Foundation and Department of Physiology and the School of Medicine, Faculty of Health Sciences, University of Pretoria.http://www.mdpi.com/journal/moleculespm2020Physiolog

Radiosensitization of breast cancer cells with a 2-methoxyestradiol analogue affects DNA damage and repair signaling in vitro

Radiation resistance and radiation-related side effects warrant research into alternative strategies in the application of this modality to cancer treatment. Designed in silico to improve the pharmacokinetics and anti-cancer properties of 2-methoxyestradiol, 2-ethyl-3-O-sulfamoyl-estra- 1,3,5(10)16-tetraene (ESE-16) disrupts microtubule dynamics and induces apoptosis. Here, we investigated whether pre-exposure of breast cancer cells to low-dose ESE-16 would affect radiation-induced deoxyribonucleic acid (DNA) damage and the consequent repair pathways. MCF-7, MDA-MB-231, and BT-20 cells were exposed to sub-lethal doses of ESE-16 for 24 h before 8 Gy radiation. Flow cytometric quantification of Annexin V, clonogenic studies, micronuclei quantification, assessment of histone H2AX phosphorylation and Ku70 expression were performed to assess cell viability, DNA damage, and repair pathways, in both directly irradiated cells and cells treated with conditioned medium. A small increase in apoptosis was observed as an early consequence, with significant repercussions on long-term cell survival. Overall, a greater degree of DNA damage was detected. Moreover, initiation of the DNA-damage repair response was delayed, with a subsequent sustained elevation. Radiation-induced bystander effects induced similar pathways and were initiated via intercellular signaling. These results justify further investigation of ESE-16 as a radiation-sensitizing agent since pre-exposure appears to augment the response of tumor cells to radiation.The National Research Foundation (NRF), NRF Thuthuka, NRF Incentive, Cancer Association of South Africa (CANSA), CANSA UP, the Research Committee (School of Medicine) of the University of Pretoria (RESCOM), the Struwig-Germeshuysen Trust, the Research Development Program from the University of Pretoria, and the Medical Research Council.https://www.mdpi.com/journal/ijmsPhysiologySDG-03:Good heatlh and well-bein

Modes of cell death induced by tetrahydroisoquinoline-based analogs in MDA-MB-231 breast and A549 lung cancer cell lines

BACKGROUND : A and B rings of the steroidal microtubule disruptor, 2-methoxyestradiol, and its analogs can be mimicked with a tetrahydroisoquinoline (THIQ) core. THIQs are cytotoxic agents with potential anticancer activities. The aim of this in vitro study was to investigate the modes of cell death induced by four nonsteroidal THIQ-based analogs, such as STX 2895, STX 3329, STX 3451 and STX 3450, on MDA-MB-231 metastatic breast and A549 epithelial lung carcinoma cells. MATERIALS AND METHODS : Cytotoxicity studies determined the half-maximal growth inhibitory concentration of the analogs to be at nanomolar concentrations without the induction of necrosis. Light and fluorescent microscopy determined that compounds caused microtubule depolymerization and displayed morphological hallmarks of apoptosis. RESULTS : Flow cytometric analyses confirmed apoptosis induction as well as an increased G2/M phase on cell cycle analysis. Furthermore, intrinsic pathway signaling was implicated due to increased cytochrome c release and a decrease in mitochondrial transmembrane potential. Potential involvement of autophagy was observed due to increased acidic vacuole formation and increased aggresome activation factor. CONCLUSION : Thus, it can be concluded that these four THIQ-based analogs exert anti- proliferative and antimitotic effects, induce apoptosis and involve autophagic processes. Further investigation into the efficacy of these potential anticancer drugs will be conducted in vitro and in vivo.The abstract of this paper was presented at the 24 Biennial Congress of the European Association for Cancer Research, July 9–12, 2016, Manchester, UK, and was published in the European Journal of Cancer.Grants from the Medical Research Council of South Africa, the Cancer Association of South Africa, National Research Foundation and the Struwig-Germeshuysen Cancer Research Trust of South Africa. BVLP is a Wellcome Trust Senior Investigator (grant 101010).http://www.dovepress.com/drug-design-development-and-therapy-journalam2018Physiolog

Apoptotic profiling of chronic myeloid leukaemia patients' platelets ex vivo before and after treatment with Imatinib

Chronic myeloid leukaemia (CML) is a malignancy of the haematopoietic stem cells. The first line of treatment for CML, especially in developing countries, remains the first-generation tyrosine kinase inhibitor, Imatinib. Patients with CML are frequently diagnosed with platelet abnormalities. However, the specific mechanism of platelet abnormalities in CML remains unclear and poorly understood. The aim of this study was therefore to determine the apoptotic profiles of CML patients ex vivo on platelets before and after treatment with Imatinib. Blood samples of healthy volunteers and CML patients at diagnosis and after 6 months treatment with Imatinib were collected. Platelet counts, viability and activation were determined. Results showed that CML patients' platelet counts were elevated upon diagnosis and these levels statistically significantly decreased after 6 months of treatment. Platelet activation was significantly increased after 6 months of treatment compared to levels at diagnosis (P-value < .05). Similarly, platelet apoptosis was also increased after 6 months of treatment. Abnormalities in platelet functioning found in this study may partly be due to clonal proliferation of haematopoietic cells in CML patients, specifically of megakaryocyte precursors as well as the inhibition of platelet tyrosine kinase's and the inhibition of platelet-derived growth factor.Cancer Association of South Africa; Medical Research Council of South Africa; National Research Foundation; School of Medicine Research Committee of the Faculty of Health Sciences, University of Pretoria; Struwig-Germeshuysen Research Trust.http://wileyonlinelibrary.com/journal/cbfhj2022HaematologyInternal MedicinePhysiolog

Cell fate following irradiation of MDA-MB-231 and MCF-7 breast cancer cells pre-exposed to the setrahydroisoquinoline sulfamate microtubule disruptor STX3451

The compound STX3451 is not commercially available.SUPPLEMENTARY MATERIAL : TABLE S1: Data analysis comparing flow cytometric quantification of individual cell cycle phases across 24-h and 48-h timelines. TABLE S2: Data analysis of flow cytometric quantification of the cell cycle distribution in MCF-7 cells exposed to STX3451 and radiation. TABLE S3: Statistical analysis of cell cycle distribution in MCF-7 cells exposed to STX3451 and radiation. TABLE S4: Data analysis comparing flow cytometric quantification of individual cell cycle phases across 24-h and 48-h timelines in MDA-MB-231 cells. TABLE S5: Statistical analysis of cell cycle progression in MDA-MB-231 cells exposed to STX3451 and radiation. TABLE S6: Statistical analysis of cell cycle distribution in MDA-MB-231 cells exposed to STX3451 and radiation. TABLE S7: Annexin-V analysis of MCF-7 cells 48-h. TABLE S8: Annexin-V statistical analysis of MDA-MB-231 48-h. TABLE S9: Colony formation in MCF-7 cells. TABLE S10: Colony formation in MDA-MB-231 cells. TABLE S11: The total number of Mn in MCF-7 cells that were terminated 2- and 24-h after radiation. TABLE S12: The total number of Mn in MDA-MB-231 cells terminated 2- and 24-h after radiation. TABLE S13: Number of Mn per cell in MCF-7 cells terminated 2-h after radiation. TABLE S14: Number of Mn per cell in MCF-7 cells terminated 24-h after radiation. TABLE S15: Number of Mn per cell in MDA-MB-231 cells terminated 2-h after radiation. TABLE S16: The number of Mn per cell in MDA-MB-231 cells that were terminated 24-h after radiation. TABLE S17: Superoxide detection in MCF-7 cells treated with the various modalities. TABLE S18: Superoxide detection in pre-sensitized MDA-MB-231 cells. TABLE S19: Statistical analysis of ATM expression in combination treated MCF-7 and MDA-MB-231 cells 2- and 24-h post-radiation. TABLE S20: Nontumored animal toxicity assay; VIDEO S1: not applicable.Atetrahydroisoquinoline (THIQ) core is able tomimic theAand B rings of 2-methoxyestradiol (2ME2), an endogenous estrogen metabolite that demonstrates promising anticancer properties primarily by disrupting microtubule dynamic instability parameters, but has very poor pharmaceutical properties that can be improved by sulfamoylation. The non-steroidal THIQ-based microtubule disruptor 2-(3-bromo-4,5-dimethoxybenzyl)-7-methoxy-6-sulfamoyloxy-1,2,3,4-tetrahydroisoquinoline (STX3451), with enhanced pharmacokinetic and pharmacodynamic profiles, was explored for the first time in radiation biology. We investigated whether 24 h pre-treatment with STX3451 could pre-sensitize MCF-7 and MDA-MB-231 breast cancer cells to radiation. This regimen showed a clear increase in cytotoxicity compared to the individual modalities, results that were contiguous in spectrophotometric analysis, flow cytometric quantification of apoptosis induction, clonogenic studies and microscopy techniques. Drug pre-treatment increased radiation-induced DNA damage, with statistically more double-strand (ds) DNA breaks demonstrated. The latter could be due to the induction of a radiation-sensitive metaphase block or the increased levels of reactive oxygen species, both evident after compound exposure. STX3451 pre-exposure may also delay DNA repair mechanisms, as the DNA damage response element ataxia telangiectasia mutated (ATM) was depressed. These in vitro findings may translate into in vivo models, with the ultimate aim of reducing both radiation and drug doses for maximal clinical effect with minimal adverse effects.The Research Committee of the University of Pretoria, the Struwig-Germeshuysen Trust, the Cancer Association of South Africa (CANSA), the National Research Foundation (NRF) and the Research Development Programme of the University of Pretoria (RDP-UP).https://www.mdpi.com/journal/moleculesam2023Physiolog

The effects of kynurenine metabolites on cell proliferation and morphology in melanoma and neuroblastoma cell lines

Research Development Programme (RDP) (UP)UCD Granthttps://drive.google.com/file/d/1juIb6_CBLaV_p1W3lCCoiy6DKY4CoWJB/view?usp=sharinghttps://drive.google.com/drive/folders/15c8nNl2iUi3wTrFeIUNHHMx9ctqb2gcc?usp=sharinghttps://drive.google.com/drive/folders/1fwqlMm1hRp4TyUwXiAXdvF6yDWyPHgcb?usp=sharin

Effect of 2-methoxyestradiol treatment on early- and late-stage breast cancer progression in a mouse model

DATA AVAILABILITY STATEMENT : The data supporting the results cited in the text can be found in the relevant articles cited in the references.The prevalence of breast cancer (BC) continues to increase and is the leading cause of cancer deaths in many countries. Numerous in vitro and in vivo studies have demonstrated that 2‐methoxyestradiol (2‐ME) has antiproliferative and antiangiogenic effects in BC, thereby inhibiting tumour growth and metastasis. We compared the effect of 2‐ME in early‐ and late‐stage BC using a transgenic mouse model— FVB/N‐Tg(MMTV‐PyVT)—of spontaneously development of aggressive mammary carcinoma with lung metastasis. Mice received 100 mg/kg 2‐ME treatment immediately when palpable mammary tumours were identified (early‐stage BC; Experimental group 1) and 28 days after palpable mammary tumours were detected (late‐stage BC; Experimental group 2). 2‐ME was administered via oral gavage three times a week for 28 days after initiation of treatment, whereas control mice received the vehicle containing 10% dimethyl sulfoxide and 90% sunflower oil for the same duration as the treatment group. Mammary tumours were measured weekly over the 28 days and at termination, blood, mammary and lung tissue were collected for analysis. Mice with a tumour volume threshold of 4000mm3 were killed before the treatment regime was completed. 2‐ME treatment of early‐stage BC led to lower levels of mammary tumour necrosis, whereas tumour mass and volume were increased. Additionally, necrotic lesions and anti‐inflammatory CD163‐expressing cells were more frequent in pulmonary metastatic tumours in this group. In contrast, 2‐ME treatment of late‐stage BC inhibited tumour growth over the 28‐day period and resulted in increased CD3+ cell number and tumour necrosis. Furthermore, 2‐ME treatment slowed down pulmonary metastasis but did not increase survival of late‐stage BC mice. Besides late‐stage tumour necrosis, none of the other results were statistically significant. This study demonstrates that 2‐ME treatment has an antitumour effect on late‐stage BC, however, with no increase in survival rate, whereas the treatment failed to demonstrate any benefit in early‐stage BC.The South African Medical Research Council Self‐Initiated Research Grant, the National Research Foundation Competitive Support for Unrated Researchers, the South African Medical Research Council University Flagship Project, the SAMRC Extramural Unit for Stem Cell Research and Therapy and the Institute for Cellular and Molecular Medicine of the University of Pretoria.http://wileyonlinelibrary.com/journal/cbfam2024ImmunologyOral Pathology and Oral BiologyPhysiologySDG-03:Good heatlh and well-bein