Curcumin suppresses gastric tumor cell growth via ROS-mediated DNA polymerase γ depletion disrupting cellular bioenergetics

Multifunctional redox-responsive and CD44 receptor targeting polymer-drug nanomedicine based curcumin and alendronate: synthesis, characterization and in vitro evaluation

The traditional therapy of cancer has systemic side effects, and many cancers, such as human breast cancer and lung cancer easily metastasize to bones, leading to the formation of secondary tumours. This study was aimed at enhancing the anti-tumour effect of curcumin (CUR) and preventing tumour spread to the bone. A novel multifunctional redox-responsive and CD44 receptor targeting polymer-drug, poly alendronate-hyaluronan-S-S-curcumin copolymer (ALN-oHA-S-S-CUR) based CUR and alendronate (ALN) were synthesized successfully with the disulphide bond linker. The structure of ALN-oHA-S-S-CUR was characterized by ¹H-NMR. The nanomedicine had natural anti-tumour drugs (CUR) as the hydrophobic kernel, and targeting CD44 receptor oligosaccharides of hyaluronan (oHA) and other anti-tumour drugs (ALN) as hydrophilic shell, named ALN-oHA-S-S-CUR conjugates, which could self-assemble into micelle-like nano-spheres in water via a dialysis method with hydrodynamic diameters of 179 ± 23 nm. Interestingly, the cur-loaded ALN-oHA-S-S-CUR micelles were stable in PBS but were capable of releasing the drug under the reducing environment. The rate of drug release was proportional to the GSH concentration. The uptake and cytotoxicity of micelles were higher in MDA-MB-231 cells than in MCF-7 cells because of a higher expression of the CD44 receptor in the former cell line. And compared to the cur-loaded oHA-CUR micelles, the cur-loaded ALN-oHA-S-S-CUR micelles had a good cellular uptake in 2D cancer cell and penetrability in 3D cancer cell spheroids. These results indicated the active targeting redox-sensitive micelles were promising as intracellular drug delivery systems for cancer treatment.

The combination of curcumin and 5-fluorouracil in cancer therapy

5-Fluorouracil (5-FU) alone or in combination with other therapeutic drugs has been widely used for clinical treatment of various cancers. However, 5-FU-based chemotherapy has limited anticancer efficacy in clinic due to multidrug resistance and dose-limiting cytotoxicity. Some molecules and genes in cancer cells, such as nuclear factor kappa B, insulin-like growth factor-1 receptor, epidermal growth factor receptor, cyclooxygenase-2, signal transducer and activator of transcription 3, phosphatase and tensin homolog deleted on chromosome ten and Bcl-2 etc. are related to the chemoresistance and sensitivity of cancer cells to 5-FU. The activation of these molecules and genes expressions in cancer cells will be increased or decreased with long-term exposure of 5-FU. Curcumin has been found to be able to negatively regulate these processes. In order to overcome the problems of 5-FU, curcumin has been used to combine with 5-FU in cancer therapy.

TFEB regulates lysosomal positioning by modulating TMEM55B expression and JIP4 recruitment to lysosomes

Lysosomal distribution is linked to the role of lysosomes in many cellular functions, including autophagosome degradation, cholesterol homeostasis, antigen presentation, and cell invasion. Alterations in lysosomal positioning contribute to different human pathologies, such as cancer, neurodegeneration, and lysosomal storage diseases. Here we report the identification of a novel mechanism of lysosomal trafficking regulation. We found that the lysosomal transmembrane protein TMEM55B recruits JIP4 to the lysosomal surface, inducing dynein-dependent transport of lysosomes toward the microtubules minus-end. TMEM55B overexpression causes lysosomes to collapse into the cell center, whereas depletion of either TMEM55B or JIP4 results in dispersion toward the cell periphery. TMEM55B levels are transcriptionally upregulated following TFEB and TFE3 activation by starvation or cholesterol-induced lysosomal stress. TMEM55B or JIP4 depletion abolishes starvation-induced retrograde lysosomal transport and prevents autophagosome-lysosome fusion. Overall our data suggest that the TFEB/TMEM55B/JIP4 pathway coordinates lysosome movement in response to a variety of stress conditions.

Live or let die: Neuroprotective and anti-cancer effects of nutraceutical antioxidants

Diet sources are closely involved in the pathogenesis of diverse neuropsychiatric disorders and cancers, in addition to inherited factors. Currently, natural products or nutraceuticals (commonly called medical foods) are increasingly employed for adjunctive therapy of these patients. However, the potential molecular mechanisms of the nutrient efficacy remain elusive. In this review, we summarized the neuroprotective and anti-cancer mechanisms of nutraceuticals. It was concluded that the nutraceuticals exerted neuroprotection and suppressed tumor growth possibly through the differential modulations of redox homeostasis. In addition, the balance between reactive oxygen species (ROS) production and ROS elimination was manipulated by multiple molecular mechanisms, including cell signaling pathways, inflammation, transcriptional regulation and epigenetic modulation, which were involved in the therapeutic potential of nutraceutical antioxidants against neurological diseases and cancers. We specifically proposed that ROS scavenging was integral in the neuroprotective potential of nutraceuticals, while alternation of ROS level (either increase or decrease) or disruption of redox homeostasis (ROS addiction) constituted the anti-cancer property of these compounds. We also hypothesized that ROS-associated ferroptosis, a novel type of lipid ROS-dependent regulatory cell death, was likely to be a critical mechanism for the nutraceutical antioxidants. Targeting ferroptosis is advantageous to develop new nutraceuticals with more effective and lower adverse reactions for curing patients with neuropsychiatric diseases or carcinomas.

Novel allylated monocarbonyl analogs of curcumin induce mitotic arrest and apoptosis by reactive oxygen species-mediated endoplasmic reticulum stress and inhibition of STAT3

Curcumin is a promising active compound from a natural source and is extensively being tested in clinical trials because of its bio-functional properties. However, poor bioavailability has hampered its clinical application. Numerous attempts have been made in our laboratory to discover analogs of curcumin with enhanced bioavailability and superior pharmacological activity. In this study, we have investigated a new series of allylated monocarbonyl analogs of curcumin (MAC) and tested their effect on gastric cancer cells. Our results show six MAC that selectively targeted cancer cell lines to inhibit growth and induce apoptosis. This activity was achieved by generation of reactive oxygen species (ROS) by MAC. We selected one effective MAC (CA10) for further investigation and show that CA10 inhibits cell growth by causing G2/M cell cycle arrest and induction of apoptotic death. CA10 induced ROS generation and subsequent activation of endoplasmic reticulum (ER) stress and inhibition of signal transducer and activator of transcription 3 (STAT3) phosphorylation, inhibits cancer cell proliferation. These anti-tumor activities of CA10 were confirmed in gastric cancer xenografts. CA10 induced ROS, activated the ER stress pathway and inhibited STAT3 phosphorylation and gastric xenografts tumor growth in mice. Our studies provide experimental evidence that MAC CA10 effectively targets gastric cancer in preclinical models by enhancing ROS and ROS-mediated signaling.

Surface decoration of selenium nanoparticles with curcumin induced HepG2 cell apoptosis through ROS mediated p53 and AKT signaling pathways

Curcumin surface decorated selenium nanoparticles (Se@Cur) has been described in this study. The apoptotic signaling pathways triggered by the Se@Cur are p53 and AKT pathways.