Combination therapy induces unfolded protein response and cytoskeletal rearrangement leading to mitochondrial apoptosis in prostate cancer

Folic acid-decorated alginate nanoparticles loaded hydrogel for the oral delivery of diferourylmethane in colorectal cancer

The disease-related suffering in colorectal cancer remains prevalent despite advancements in the field of drug delivery. Chemotherapy-related side effects and non-specificity remain a challenge in drug delivery. The great majority of hydrophobic drugs cannot be successfully delivered to the colon orally mainly due to poor solubility, low bioavailability, pH differences, and food interactions. Polymeric nanoparticles are potential drug delivery candidates but there are numerous limitations to their usefulness in colon cancer. The nanoparticles are removed from the body rapidly by p-glycoprotein efflux, inactivation, or breakdown by enzymes limiting their efficiency. Furthermore, there is a lack of selectivity in targeting cancer cells; nanoparticles may also target healthy cells, resulting in toxicity and adverse effects. The study aimed to use nanoparticles for specific targeting of the colorectal tumor cells via the oral route of administration without adverse effects. Folic acid (FA), a cancer-targeting ligand possessing a high affinity for folate receptors overexpressed in colorectal cancers was conjugated to sodium alginate- nanoparticles by NH₂-linkage. The folic-acid conjugated nanoparticles (FNPs) were delivered to the colon by a pH-sensitive hydrogel synthesized by the free radical polymerization method to provide sustained drug release. The developed system referred to as the "Hydrogel-Nano (HN) drug delivery system," was specifically capable of delivering diferourylmethane to the colon. The HN system was characterized by DLS, FTIR, XRD, TGA, DSC, and SEM. The FNPs size, polydispersity index, and zeta potential were measured. The folic acid-conjugation to nanoparticles' surface was studied by UV-visible spectroscopy using Beer-Lambert's law. In-vitro studies, including sol-gel, porosity, drug loading, entrapment efficiency, etc., revealed promising results. The swelling and release studies showed pH-dependent release of the drug in colonic pH 7.4. Cellular uptake and cytotoxicity studies performed on FR-overexpressed Hela cell lines and FR-negative A-549 cell lines showed facilitated uptake of nanoparticles by folate receptors. A threefold increase in C_max and prolongation of the mean residence time (MRT) to 14.52 +/- 0.217 h indicated sustained drug release by the HN system. The findings of the study can provide a sufficient ground that the synergistic approach of the HN system can deliver hydrophobic drugs to colorectal cancer cells via the oral route, but further in-vivo animal cancer model studies are required.

Manganese Dioxide-Based Nanocarrier Delivers Paclitaxel to Enhance Chemotherapy against Orthotopic Glioma through Hypoxia Relief

Chemotherapy plays an important role in treating cancers in clinic. Hypoxia-mediated chemoresistance remains a major hurdle for effective tumor chemotherapy. Herein, a new class of tLyP-1-modified dopamine (DOPA)-β-cyclodextrin (CD)-coated paclitaxel (PTX)- and manganese dioxide (MnO₂ )-loaded nanoparticles (tLyP-1-CD-DOPA-MnO₂ @PTX) is developed to enhance glioma chemotherapy. The nanomedicine delivered to the tumor site decomposes in response to the weak acidity and high hydrogen peroxide in the tumor microenvironment (TME), resulting in collapse of the system to release PTX and generates Mn²⁺ and O₂ . In a rat model of intracranial glioma, tLyP-1-CD-DOPA-MnO₂ @PTX can efficiently pass through the blood-brain-barrier to accumulate in tumor sites. The hypoxia in TME can be relieved via O₂ generated by MnO₂ and the reactive oxygen species produced by Mn²⁺ can kill tumor cells. The tLyP-1-CD-DOPA-MnO₂ @PTX nanoparticles exert a remarkable antitumor effect by promoting apoptosis and inhibiting proliferation of tumor cells in addition to enabling real-time tumor monitoring with magnetic resonance imaging. This MnO₂ -based theranostic medicine will offer a novel strategy to simultaneously enhance chemotherapy and achieve real-time imaging of therapeutic process in glioma treatment.

MAP4K4 promotes pancreatic tumorigenesis via phosphorylation and activation of mixed lineage kinase 3

MAP4K4 is a Ste20 member and reported to play important roles in various pathologies, including in cancer. However, the mechanism by which MAP4K4 promotes pancreatic cancer is not fully understood. It is suggested that MAP4K4 might function as a cancer promoter via specific downstream target(s) in an organ-specific manner. Here we identified MLK3 as a direct downstream target of MAP4K4. The MAP4K4 and MLK3 associates with each other, and MAP4K4 phosphorylates MLK3 on Thr738 and increases MLK3 kinase activity and downstream signaling. The phosphorylation of MLK3 by MAP4K4 promotes pancreatic cancer cell proliferation, migration, and colony formation. Moreover, MAP4K4 is overexpressed in human pancreatic tumors and directly correlates with the disease progression. The MAP4K4-specific pharmacological inhibitor, GNE-495, impedes pancreatic cancer cell growth, migration, induces cell death, and arrests cell cycle progression. Additionally, the GNE-495 reduced the tumor burden and extended survival of the KPC mice with pancreatic cancer. The MAP4K4 inhibitor also reduced MAP4K4 protein expression, tumor stroma, and induced cell death in murine pancreatic tumors. These findings collectively suggest that MLK3 phosphorylation by MAP4K4 promotes pancreatic cancer, and therefore therapies targeting MAP4K4 might alleviate the pancreatic cancer tumor burden in patients.

Roles of mitochondrial unfolded protein response in mammalian stem cells

The mitochondrial unfolded protein response (UPR^mt) is an evolutionarily conserved adaptive mechanism for improving cell survival under mitochondrial stress. Under physiological and pathological conditions, the UPR^mt is the key to maintaining intracellular homeostasis and proteostasis. Important roles of the UPR^mt have been demonstrated in a variety of cell types and in cell development, metabolism, and immune processes. UPR^mt dysfunction leads to a variety of pathologies, including cancer, inflammation, neurodegenerative disease, metabolic disease, and immune disease. Stem cells have a special ability to self-renew and differentiate into a variety of somatic cells and have been shown to exist in a variety of tissues. These cells are involved in development, tissue renewal, and some disease processes. Although the roles and regulatory mechanisms of the UPR^mt in somatic cells have been widely reported, the roles of the UPR^mt in stem cells are not fully understood. The roles and functions of the UPR^mt depend on stem cell type. Therefore, this paper summarizes the potential significance of the UPR^mt in embryonic stem cells, tissue stem cells, tumor stem cells, and induced pluripotent stem cells. The purpose of this review is to provide new insights into stem cell differentiation and tumor pathogenesis.

Folate receptor targeted delivery of paclitaxel to breast cancer cells via folic acid conjugated graphene oxide grafted methyl acrylate nanocarrier

The adaptability, joint with a large surface area, electronic flexibility, high intrinsic mobility, high mechanical strength and supreme thermal conductivity have condensed graphene family materials attractive as technological tools of the drug delivery system. In this present study, investigate a modified graphene oxide-methyl acrylate (GO-g-MA) nanocarrier for targeted anti-cancer drug delivery in breast cancer cells and the GO-g-MA fascinated with folic acidas a targeting ligand to target the cancer cells. Paclitaxel (PTX) was assembled through π-π stacking, hydrophophic interaction on the surface of the GO-g-MA/FA carrier. Structural modification of GO-g-MA, functionalization of targeting ligands GO-g-MA/FA and drug loaded GO-g-MA/FA-PTX was characterized and confirmed through FTIR, XRD, SEM,TEM and AFM analysis. The in-vitro drug release pattern of PTX from the GO-g-MA/FA was examined in different pH ranges. An MTT assay was performed to evaluate the cytotoxicity behaviour of the carrier and PTX loaded nanocarrier in the human breast cancer cell line (MDA-MB-231). GO-g-MA/FA-PTX carrier showed that 39% of cytotoxic effect. Furthermore, the in-vivo (DMBA induced breast cancer rats) studies were carried out and treatment with PTX- loaded GO-g-MA/FA nanocarrier attenuates the levels of mitochondrial citric acids enzymes to near normal.

Nimbolide reduces CD44 positive cell population and induces mitochondrial apoptosis in pancreatic cancer cells

Pancreatic ductal adenocarcinoma (PDAC) is highly aggressive disease and current treatment regimens fail to effectively cure PDAC. Development of resistance to current therapy is one of the key reasons for this outcome. Nimbolide (NL), a triterpenoid obtained from Azadirachta indica, exhibits anticancer properties in various cancer including PDAC cells. However, the underlying mechanism of this anticancer agent in PDAC cells remains undefined. We show that NL exerts a higher level of apoptotic cell death compared to the first-line agent gemcitabine for PDAC, as well as other anticancer agents including sorafenib and curcumin. The anticancer efficacy of NL was further evidenced by a reduction in the CD44⁺ as well as cancer stem-like cell (CSC) population, as it causes decreased sphere formation. Mechanistically, the anticancer efficacy of NL associates with reduced mutant p53 as well as increased mitochondrial activity in the form of increased mitochondrial reactive oxygen species and mitochondrial mass. Together, this study highlights the therapeutic potential of NL in mutant p53 expressing pancreatic cancer.

Sensitivity to antitubulin chemotherapeutics is potentiated by a photoactivable nanoliposome

Anti-microtubule therapy represents one of the most strategic cancer therapeutics. Tublin inhibitor such as paclitaxel (PTX) is well known to disturb the dynamic nature of microtubules, being considered as the first-line drug for various malignancies. However, PTX does not show favorable clinical outcomes due to serious systemic toxicities and low selectivity. The development of PTX delivery systems and combinational therapies has been conducted to enhance PTX efficacy with poorly defined mechanisms. Herein, we introduced a reactive oxygen species producible composite liposome based on a new photosensitizer sinoporphyrin sodium (DVDMS) to enhance the therapeutic effect of PTX through photochemical stimulation, and more importantly, the pivotal molecular regulation mechanisms were specifically explored. Compared with DVDMS-liposome (DL) or PTX-liposome (PL), the composite liposome DVDMS-PTX-liposome (PDL) exhibited a superior anti-tumor advantage following laser irradiation against MCF-7 breast cancer. The localized PTX release after PDL administration greatly decreased the drug dosage and laser power required, leading to much higher safety and lower costs. In vitro, the combined treatment significantly suppressed cell viability and potentiated cell apoptosis. The apoptotic central regulator Mcl-1 as a favorable target, was evaluated in association with photochemically enhanced sensitivity to anti-tubulin chemotherapeutics. Phosphorylation of Mcl-1 led to its direct degradation with the proteasome system, making it relatively unstable and potentiating cell death resulting from photochemical synergy via PDL plus laser irradiation. Further, a decrease in ATP production and glycolysis after PDL plus laser would prevent the possible energy-switch and apoptosis-escape by PTX alone treatment, thereby resulted in increased cell death in combinational therapy. Systemic administration of PDL followed by in vivo photochemotherapy achieved significantly improved therapeutic effects compared to either alone. And, the intrinsic fluorescence of DVDMS facilitated real-time imaging of PDL in tumors. Therefore, the present strategy with details at the molecular regulation could be a promising platform for antitublin chemotherapeutics.

Endoplasmic reticulum-mediated unfolded protein response and mitochondrial apoptosis in cancer

Abrogation of endoplasmic reticulum (ER) protein folding triggered by exogenous or endogenous factors, stimulates a cellular stress response, termed ER stress. ER stress re-establishes ER homeostasis through integrated signaling termed the ER-unfolded protein response (UPR^ER). In the presence of severe toxic or prolonged ER stress, the pro-survival function of UPR^ER is transformed into a lethal signal transmitted to and executed through mitochondria. Mitochondria are key for both apoptotic and autophagic cell death. Thus ER is vital in sensing and coordinating stress pathways to maintain overall physiological homeostasis. However, this function is deregulated in cancer, resulting in resistance to apoptosis induction in response to various stressors including therapeutic agents. Here we review the connections between ER stress and mitochondrial apoptosis, describing potential cancer therapeutic targets.

Combination therapy induces unfolded protein response and cytoskeletal rearrangement leading to mitochondrial apoptosis in prostate cancer

Development of therapeutic resistance is responsible for most prostate cancer (PCa) related mortality. Resistance has been attributed to an acquired or selected cancer stem cell phenotype. Here we report the histone deacetylase inhibitor apicidin (APC) or ER stressor thapsigargin (TG) potentiate paclitaxel (TXL)-induced apoptosis in PCa cells and limit accumulation of cancer stem cells. TXL-induced responses were modulated in the presence of TG with increased accumulation of cells at G1-phase, rearrangement of the cytoskeleton, and changes in cytokine release. Cytoskeletal rearrangement was associated with modulation of the cytoplasmic and mitochondrial unfolded protein response leading to mitochondrial dysfunction and release of proapoptotic proteins from mitochondria. TXL in combination with APC or TG enhanced caspase activation. Importantly, TXL in combination with TG induced caspase activation and apoptosis in X-ray resistant LNCaP cells. Increased release of transforming growth factor-beta (TGF-β) was observed while phosphorylated β-catenin level was suppressed with TXL combination treatments. This was accompanied by a decrease in the CD44(+)CD133(+) cancer stem cell-like population, suggesting treatment affects cancer stem cell properties. Taken together, combination treatment with TXL and either APC or TG induces efficient apoptosis in both proliferating and cancer stem cells, suggesting this therapeutic combination may overcome drug resistance and recurrence in PCa.