Antitumor Effects of a Sesquiterpene Derivative from Marine Sponge in Human Breast Cancer Cells

From Beach to the Bedside: Harnessing Mitochondrial Function in Human Diseases Using New Marine-Derived Strategies

Mitochondria are double-membrane organelles within eukaryotic cells that act as cellular power houses owing to their ability to efficiently generate the ATP required to sustain normal cell function. Also, they represent a "hub" for the regulation of a plethora of processes, including cellular homeostasis, metabolism, the defense against oxidative stress, and cell death. Mitochondrial dysfunctions are associated with a wide range of human diseases with complex pathologies, including metabolic diseases, neurodegenerative disorders, and cancer. Therefore, regulating dysfunctional mitochondria represents a pivotal therapeutic opportunity in biomedicine. Marine ecosystems are biologically very diversified and harbor a broad range of organisms, providing both novel bioactive substances and molecules with meaningful biomedical and pharmacological applications. Recently, many mitochondria-targeting marine-derived molecules have been described to regulate mitochondrial biology, thus exerting therapeutic effects by inhibiting mitochondrial abnormalities, both in vitro and in vivo, through different mechanisms of action. Here, we review different strategies that are derived from marine organisms which modulate specific mitochondrial processes or mitochondrial molecular pathways and ultimately aim to find key molecules to treat a wide range of human diseases characterized by impaired mitochondrial function.

Evaluation of antitumoral effect of Hibiscus sabdariffa extract on human breast cancer cells

BackgroundBreast cancer is the most frequent tumor in women. Natural substances represent an important source of innovative therapeutic solutions, eventually integrating or substituting conventional drugs and chemicals. Hibiscus sabdariffa L. is a plant of the Malvaceae family that has raised interest thanks to its anti-inflammatory, antioxidant and anticancer effects. In this work, we evaluated the antitumoral effects of an enriched fraction of Hibiscus sabdariffa L. extract (HsEF) in two human breast cancer cell lines, MCF-7(ERα +) and MDA-MB-231 (triple negative).

Methods and resultsCell viability was assessed by MTT and Trypan blue assays. HsEF reduced both cell lines viability in a dose and time dependent manner and this effect results irreversible. In MCF-7 cells immunofluorescence experiments, demonstrated that HsEF induced ERα trans-location from nucleus to perinuclear area and in cytoplasmic compartment. qRT-PCR and western blotting high-lighted that HsEF reduced ERα, BRCA1 and caveolin1 gene and protein expression in MCF-7 cells, but not in MDA-MB-231 cells. Moreover, we demonstrated that HsEF reduced proteasome activity, an increased autophagy, impair migration and invasion in both cell lines.

ConclusionsOur data suggest HsEF has an antitumoral effects on both breast tumor cells examined and that ERα involvement could explain the differences observed between the two cell lines.

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Breast cancer conventional treatments have some limitations, such as drug resistance, metastasis and high heterogeneity.

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Natural products and their metabolites represent an alternative and an interesting therapeutic option.

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H. sabdariffa reduce cell viability, cell migration and cell invasion of breast cancer cell lines MCF-7 and MDA-MB-231.

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H. sabdariffa inhibits proteasome and induces autophagy.

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H.sabdariffa induce estrogen receptor downregulation and intracellular de-localization.

Apoptotic effect of sulfated galactofucan from marine macroalga Turbinaria ornata on hepatocellular and ductal carcinoma cells

Tumor protein or cellular tumor antigen p53, is considered a critical transcriptional regulation factor, which can suppress the growth of tumor cells by activating other functional genes. The current study appraised the p53 activation pathways, which could be used as an alternative therapeutic strategy for the treatment of hepatocellular and ductal carcinoma. Algal polysaccharides have been used as emerging sources of bioactive natural pharmacophores. A sulfated galactofucan characterized as [→1)-O-4-sulfonato-α-fucopyranose-(3 → 1)-α-fucopyranose-(3→] as the main branch with [→1)-6-O-acetyl-β-galactopyranose-(4→] as side chain isolated from marine macroalga Turbinaria ornata exhibited prospective apoptosis on HepG2 (hepatocellular carcinoma) and MCF7 (ductal carcinoma) cells. Annexin V-fluorescein isothiocyanate-propidium iodide study displayed higher early apoptosis in MCF7 and HepG2 cell lines (56 and 24.2%, respectively) treated with TOP-3 (at IC50 concentration) than those administered with standard camptothecin. Upregulation of the p53 gene expression was perceived in TOP-3 treated HepG2 and MCF7 cells.

Adipokines as Regulators of Autophagy in Obesity-Linked Cancer

Excess body weight and obesity have become significant risk factors for cancer development. During obesity, adipose tissue alters its biological function, deregulating the secretion of bioactive factors such as hormones, cytokines, and adipokines that promote an inflammatory microenvironment conducive to carcinogenesis and tumor progression. Adipokines regulate tumor processes such as apoptosis, proliferation, migration, angiogenesis, and invasion. Additionally, it has been found that they can modulate autophagy, a process implicated in tumor suppression in healthy tissue and cancer progression in established tumors. Since the tumor-promoting role of autophagy has been well described, the process has been suggested as a therapeutic target in cancer. However, the effects of targeting autophagy might depend on the tumor type and microenvironmental conditions, where circulating adipokines could influence the role of autophagy in cancer. Here, we review recent evidence related to the role of adipokines in cancer cell autophagy in an effort to understand the tumor response in the context of obesity under the assumption of an autophagy-targeting treatment.

Marine Compounds, Mitochondria, and Malignancy: A Therapeutic Nexus

The marine environment is important yet generally underexplored. It contains new sources of functional constituents that can affect various pathways in food processing, storage, and fortification. Bioactive secondary metabolites produced by marine microorganisms may have significant potential applications for humans. Various components isolated from disparate marine microorganisms, including fungi, microalgae, bacteria, and myxomycetes, showed considerable biological effects, such as anticancer, antioxidant, antiviral, antibacterial, and neuroprotective activities. Growing studies are revealing that potential anticancer effects of marine agents could be achieved through the modulation of several organelles. Mitochondria are known organelles that influence growth, differentiation, and death of cells via influencing the biosynthetic, bioenergetic, and various signaling pathways related to oxidative stress and cellular metabolism. Consequently, mitochondria play an essential role in tumorigenesis and cancer treatments by adapting to alterations in environmental and cellular conditions. The growing interest in marine-derived anticancer agents, combined with the development and progression of novel technology in the extraction and cultures of marine life, led to revelations of new compounds with meaningful pharmacological applications. This is the first critical review on marine-derived anticancer agents that have the potential for targeting mitochondrial function during tumorigenesis. This study aims to provide promising strategies in cancer prevention and treatment.

The Impact of Oxidative Stress and AKT Pathway on Cancer Cell Functions and Its Application to Natural Products

Oxidative stress and AKT serine-threonine kinase (AKT) are responsible for regulating several cell functions of cancer cells. Several natural products modulate both oxidative stress and AKT for anticancer effects. However, the impact of natural product-modulating oxidative stress and AKT on cell functions lacks systemic understanding. Notably, the contribution of regulating cell functions by AKT downstream effectors is not yet well integrated. This review explores the role of oxidative stress and AKT pathway (AKT/AKT effectors) on ten cell functions, including apoptosis, autophagy, endoplasmic reticulum stress, mitochondrial morphogenesis, ferroptosis, necroptosis, DNA damage response, senescence, migration, and cell-cycle progression. The impact of oxidative stress and AKT are connected to these cell functions through cell function mediators. Moreover, the AKT effectors related to cell functions are integrated. Based on this rationale, natural products with the modulating abilities for oxidative stress and AKT pathway exhibit the potential to regulate these cell functions, but some were rarely reported, particularly for AKT effectors. This review sheds light on understanding the roles of oxidative stress and AKT pathway in regulating cell functions, providing future directions for natural products in cancer treatment.

Induction of apoptosis using ATN as a novel Yes-associated protein inhibitor in human oral squamous cell carcinoma cells

Oral squamous cell carcinoma (OSCC) represents a clinical challenge due to the lack of effective therapy to improve prognosis. Hippo/Yes-associated protein (YAP) signaling has emerged as a promising therapeutic target for squamous cell carcinoma treatment. In this study, we investigated the antitumor activity and underlying mechanisms of {[N-(4-(5-(3-(3-(4-acetamido-3-(trifluoromethyl)phenyl)ureido)phenyl)-1,2,4-oxadiazol-3-yl)-3-chlorophenyl)-nicotinamide]} (ATN), a novel YAP inhibitor, in OSCC cells. ATN exhibited differential antiproliferative efficacy against OSCC cells (IC₅₀ as low as 0.29 μM) versus nontumorigenic human fibroblast cells (IC₅₀  = 1.9 μM). Moreover, ATN effectively suppressed the expression of YAP and YAP-related or downstream targets, including Akt, p-AMPK, c-Myc, and cyclin D1, which paralleled the antiproliferative efficacy of ATN. Supporting the roles of YAP in regulating cancer cell survival and migration, ATN not only induced caspase-dependent apoptosis, but also suppressed migration activity in OSCC. Mechanistically, the antitumor activity of ATN in OSCC was attributed, in part, to its ability to regulate Mcl-1 expression. Together, these findings suggest a translational potential of YAP inhibitors, represented by ATN as anticancer therapy for OSCC.