The involvement of a chemokine receptor antagonist CTCE-9908 and kynurenine metabolites in cancer development

Employing antagonistic C-X-C motif chemokine receptor 4 antagonistic peptide functionalized NaGdF4 nanodots for magnetic resonance imaging-guided biotherapy of breast cancer

C-X-C motif chemokine receptor 4 (CXCR4) is a promising therapeutic target of breast cancer because it is overexpressed on cell surface of all molecular subtypes of breast cancer including triplenegative breast cancer (TNBC). Herein, CXCR4 antagonistic peptide-NaGdF4 nanodot conjugates (termed as anti-CXCR4-NaGdF4 NDs) have been constructed for magnetic resonance imaging (MRI)-guided biotherapy of TNBC through conjugation of the C-X-C Motif Chemokine 12 (CXCL12)-derived cyclic peptide with tryptone coated NaGdF4 nanodots (5 ± 0.5 nm in diameter, termed as Try-NaGdF4 NDs). The as-prepared anti-CXCR4-NaGdF4 NDs exhibits high longitudinal relaxivity (r1) value (21.87 mM-1S-1), reasonable biocompatibility and good tumor accumulation ability. The features of anti-CXCR4-NaGdF4 NDs improve the tumor-MRI sensitivity and facilitate tumor biotherapy after injection in mouse-bearing MDA-MB-231 tumor model in vivo. MRI-guided biotherapy using anti-CXCR4-NaGdF4 NDs enables to suppress 46% tumor growth. In addition, about 47% injection dose of anti-CXCR4-NaGdF4 NDs is found in the mouse urine at 24 h post-injection. These findings demonstrate that anti-CXCR4-NaGdF4 NDs enable to be used as renal clearable nanomedicine for biotherapy and MRI of breast cancer.

In vitro effects and mathematical modelling of CTCE-9908 (a chemokine receptor 4 antagonist) on melanoma cell survival

CTCE-9908, a CXC chemokine receptor 4 (CXCR4) antagonist, prevents CXCR4 phosphorylation and inhibits the interaction with chemokine ligand 12 (CXCL12) and downstream signalling pathways associated with metastasis. This study evaluated the in vitro effects of CTCE-9908 on B16 F10 melanoma cells with the use of mathematical modelling. Crystal violet staining was used to construct a mathematical model of CTCE-9908 B16 F10 (melanoma) and RAW 264.7 (non-cancerous macrophage) cell lines on cell viability to predict the half-maximal inhibitory concentration (IC50). Morphological changes were assessed using transmission electron microscopy. Flow cytometry was used to assess changes in cell cycle distribution, apoptosis via caspase-3, cell survival via extracellular signal-regulated kinase1/2 activation, CXCR4 activation and CXCL12 expression. Mathematical modelling predicted IC50 values from 0 to 100 h. At IC50, similar cytotoxicity between the two cell lines and ultrastructural morphological changes indicative of cell death were observed. At a concentration 10 times lower than IC50, CTCE-9908 induced inhibition of cell survival (p = 0.0133) in B16 F10 cells but did not affect caspase-3 or cell cycle distribution in either cell line. This study predicts CTCE-9908 IC50 values at various time points using mathematical modelling, revealing cytotoxicity in melanoma and non-cancerous cells. CTCE-9908 significantly inhibited melanoma cell survival at a concentration 10 times lower than the IC50 in B16 F10 cells but not RAW 264.7 cells. However, CTCE-9908 did not affect CXCR4 phosphorylation, apoptosis,\ or cell cycle distribution in either cell line.

L-kynurenine and quinolinic acid inhibited markers of cell survival in B16 F10 melanoma cells in vitro

Melanoma is an aggressive malignancy and remains a major cause of skin cancer mortality, highlighting the need for new treatment strategies. Recent findings revealed that L-kynurenine and quinolinic acid induce cytotoxicity and morphological changes in B16 F10 melanoma cells in vitro. This paper highlights the effects of L-kynurenine and quinolinic acid at previously determined half-maximal inhibitory concentrations on cell cycle progression, cell death and extracellular signal-regulated protein kinase inhibition. Melanoma, B16 F10 and murine macrophages, RAW 264.7 cells were used in this study, as both cell lines express all the enzymes associated with the kynurenine pathway. Post exposure to the compounds at half-maximal inhibitory concentrations, transmission electron microscopy was used to assess intracellular morphological changes. Flow cytometry was used to analyse cell cycle progression and quantify apoptosis via the dual staining of Annexin V and propidium iodide and cell survival via extracellular signal-regulated protein kinase. L-kynurenine and quinolinic acid at half-maximal inhibitory concentrations induced intracellular morphological changes representative of cell death. Flow cytometry revealed alterations in cell cycle distribution, increased apoptosis and significantly inhibition of cell survival. L-kynurenine and quinolinic acid are exogenous kynurenine compounds which inhibited cell survival through extracellular signal-regulated protein kinase inhibition, induced cell cycle alterations and induced apoptosis in B16 F10 melanoma cells.

Decoding the synergistic potential of MAZ-51 and zingerone as therapy for melanoma treatment in alignment with sustainable development goals

Melanoma, an invasive class of skin cancer, originates from mutations in melanocytes, the pigment-producing cells. Globally, approximately 132,000 new cases are reported each year, and in South Africa, the incidence stands at 2.7 per 100,000 people, signifying a worrisome surge in melanoma rates. Therefore, there is a need to explore treatment modalities that will target melanoma's signalling pathways. Melanoma metastasis is aided by ligand activity of transforming growth factor-beta 1 (TGF-β1), vascular endothelial growth factor-C (VEGF-C) and C-X-C chemokine ligand 12 (CXCL12) which bind to their receptors and promote tumour cell survival, lymphangiogenesis and chemotaxis. (3-(4-dimethylaminonaphthelen-1-ylmethylene)-1,3-dihydroindol-2-one) MAZ-51 is an indolinone-based molecule that inhibits VEGF-C induced phosphorylation of vascular endothelial growth factor receptor 3 (VEGFR-3). Despite the successful use of conventional cancer therapies, patients endure adverse side effects and cancer drug resistance. Moreover, conventional therapies are toxic to the environment and caregivers. The use of medicinal plants and their phytochemical constituents in cancer treatment strategies has become more widespread because of the rise in drug resistance and the development of unfavourable side effects. Zingerone, a phytochemical derived from ginger exhibits various pharmacological properties positioning it as a promising candidate for cancer treatment. This review provides an overview of melanoma biology and the intracellular signalling pathways promoting cell survival, proliferation and adhesion. There is a need to align health and environmental objectives within sustainable development goals 3 (good health and well-being), 13 (climate action) and 15 (life on land) to promote early detection of skin cancer, enhance sun-safe practices, mitigation of environmental factors and advancing the preservation of biodiversity, including medicinal plants. Thus, this review discusses the impact of cytostatic cancer drugs on patients and the environment and examines the potential use of phytochemicals as adjuvant therapy.

An in vitro investigation of l-kynurenine, quinolinic acid, and kynurenic acid on B16 F10 melanoma cell cytotoxicity and morphology

The metastatic behavior of melanoma has accentuated the need for specific therapy targets. Compounds, namely l-kynurenine ( l-kyn), quinolinic acid (Quin), and kynurenic acid (KA) previously displayed antiproliferative and cytotoxic effects in vitro against cancer cells. Despite the growing interest in these compounds there are limited studies examining the in vitro effects on melanoma. In B16 F10 melanoma cells, RAW 264.7 macrophage cells, and HaCat keratinocyte cells, postexposure to the compounds, crystal violet staining was used to determine the half-maximal inhibitory concentration (IC50 ), whereas polarization-optical transmitted light differential interference contrast and light microscopy after hematoxylin and eosin (H&E) staining was used to assess morphological changes.  l-kyn, Quin, and KA-induced cytotoxicity in all cell lines, with  l-kyn being the most cytotoxic compound.  l-kyn and KA at IC50 -induced morphological changes in B16 F10, RAW 264.7, and HaCat cell lines, whereas Quin had effects on B16 F10 and RAW 264.7 cells but did not affect HaCat cells.  l-kyn, Quin, and KA each display different levels of cytotoxicity, which were cell line specific.  l-kyn was shown to be the most potent compound against all cell lines and may offer future treatment strategies when combined with other viable treatments against melanoma.

The tryptophan-kynurenine pathway in immunomodulation and cancer metastasis

INTRODUCTION

The activation of the kynurenine pathway in cancer progression and metastasis through immunomodulatory pathways has drawn attention to the potential for kynurenine pathway inhibition. The activation of the kynurenine pathway, which results in the production of kynurenine metabolites through the degradation of tryptophan, promotes the development of intrinsically malignant properties in cancer cells while facilitating tumour immune escape. In addition, kynurenine metabolites act as biologically active substances to promote cancer development and metastasis.

METHODS

A literature review was conducted to investigate the role of the tryptophan-kynurenine pathway in immunomodulation and cancer metastasis.

RESULTS

Evidence suggests that several enzymes and metabolites implicated in the kynurenine pathway are overexpressed in various cancers. As such, the tryptophan pathway represents a promising target for cancer treatment. However, downstream signalling pathways, including aryl hydrocarbon receptor activation, have previously induced diverse biological effects in various malignancies, which resulted in either the promotion or the inhibition of metastasis.

CONCLUSION

As a result, a thorough investigation of the kynurenine pathway and its regulatory mechanisms is necessary in order to properly comprehend the effects of kynurenine pathway activation involved in cancer development and metastasis.

Metastasis prevention: How to catch metastatic seeds

Despite considerable advances in the evolution of anticancer therapies, metastasis still remains the main cause of cancer mortality. Therefore, current strategies for cancer cure should be redirected towards prevention of metastasis. Targeting metastatic pathways represents a promising therapeutic opportunity aimed at obstructing tumor cell dissemination and metastatic colonization. In this review, we focus on preclinical studies and clinical trials over the last five years that showed high efficacy in suppressing metastasis through targeting lymph node dissemination, tumor cell extravasation, reactive oxygen species, pre-metastatic niche, exosome machinery, and dormancy.