Adenovirus-mediated expression of MOAP-1, Bax and RASSF1A antagonizes chemo-drug resistance of human breast cancer cells expressing cancer stem cell markers.

Cancer is one of the major leading causes of mortality globally and chemo-drug-resistant cancers pose significant challenges to cancer treatment by reducing patient survival rates and increasing treatment costs. Although the mechanisms of chemoresistance vary among different types of cancer, cancer cells are known to share several hallmarks, such as their resistance to apoptosis as well as the ability of cancer stem cells to produce metastatic daughter cells that are resistant to chemotherapy. To address the issue of chemo-drug resistance in cancer cells, a tetracistronic expression construct, Ad-MBR-GFP, encoding adenovirus-mediated expression of MOAP-1, Bax, RASSSF1A, and GFP, was generated to investigate its potential activity in reducing or inhibiting the chemo-drug resistant activity of the human breast cancer cells, MCF-7-CR and MDA-MB-231. When infected by Ad-MBR-GFP, the cancer cells exhibited round cell morphology and nuclei condensation with positive staining for annexin-V. Furthermore, our results showed that both MCF-7-CR and MDA-MB-231 cells stained positively for CD 44 and negatively for CD 24 (CD44+/CD24-) with high levels of endogenous ALDH activity whereas SNU-1581 breast cancer cells were identified as CD 44-/CD 24- cells with relatively low levels of endogenous ALDH activity and high sensitivity toward chemo-drugs, suggesting that both CD 44 and ALDH activity contribute to chemo-drug resistance. Moreover, both MCF-7-CR and MDA-MB-231 cells showed strong chemo-drug sensitivity to cisplatin when the cells were infected by Ad-MBR-GFP, leading to 9-fold and 2-fold reduction in the IC 50 values when compared to cisplatin treatment alone, respectively. The data were further supported by 3D (soft agar) and spheroid cell models of MCF-7-CR and MDA-MB-231 cells which showed a 2-fold reduction of a number of cell colonies and spheroid size when treated with both Ad-MBR-GFP and cisplatin, and compared to control. Other than chemo-sensitivity, Ad-MBR-GFP-infected cancer cells retarded cell migration. Flow cytometry analysis showed that the mechanism of action of Ad-MBR-GFP involved cell cycle arrest at the G1 phase and inhibition of cellular DNA synthesis. Taken together, our investigation showed that Ad-MBR-GFP mediated chemo-drug sensitization in the infected cancer cells involved the activation of apoptosis signaling, cell cycle arrest, and inhibition of DNA synthesis, suggesting that Ad-MBR-GFP is potentially efficacious for the treatment of chemo-drug resistant cancers.

Pharmacological inhibition of STING reduces neuroinflammation-mediated damage post-traumatic brain injury.

BACKGROUND AND PURPOSE: Traumatic brain injury (TBI) remains a major public health concern worldwide with unmet effective treatment. Stimulator of interferon genes (STING) and its downstream type-I interferon (IFN) signalling are now appreciated to be involved in TBI pathogenesis. Compelling evidence have shown that STING and type-I IFNs are key in mediating the detrimental neuroinflammatory response after TBI. Therefore, pharmacological inhibition of STING presents a viable therapeutic opportunity in combating the detrimental neuroinflammatory response after TBI. EXPERIMENTAL APPROACH: This study investigated the neuroprotective effects of the small-molecule STING inhibitor n-(4-iodophenyl)-5-nitrofuran-2-carboxamide (C-176) in the controlled cortical impact mouse model of TBI in 10- to 12-week-old male mice. Thirty minutes post-controlled cortical impact surgery, a single 750-nmol dose of C-176 or saline (vehicle) was administered intravenously. Analysis was conducted 2 h and 24 h post-TBI. KEY RESULTS: Mice administered C-176 had significantly smaller cortical lesion area when compared to vehicle-treated mice 24 h post-TBI. Quantitative temporal gait analysis conducted using DigiGait™ showed C-176 administration attenuated TBI-induced impairments in gait symmetry, stride frequency and forelimb stance width. C-176-treated mice displayed a significant reduction in striatal gene expression of pro-inflammatory cytokines Tnf-α, Il-1ß and Cxcl10 compared to their vehicle-treated counterparts 2 h post-TBI. CONCLUSION AND IMPLICATIONS: This study demonstrates the neuroprotective activity of C-176 in ameliorating acute neuroinflammation and preventing white matter neurodegeneration post-TBI. This study highlights the therapeutic potential of small-molecule inhibitors targeting STING for the treatment of trauma-induced inflammation and neuroprotective potential.

2D nanostructures: Potential in diagnosis and treatment of Alzheimer's disease.

Two-dimensional (2D) nanomaterials have garnered enormous attention seemingly due to their unusual architecture and properties. Graphene and graphene oxide based 2D nanomaterials remained the most sought after for several years but the quest to design superior 2D nanomaterials which can find wider application gave rise to development of non-graphene 2D materials as well. Consequently, in addition to graphene based 2D nanomaterials, 2D nanostructures designed using macromolecules (such as DNAs, proteins, peptides and peptoids), transition metal dichalcogenides, transition-metal carbides and/or nitrides (MXene), black phosphorous, chitosan, hexagonal boron nitrides, and graphitic carbon nitride, and covalent organic frameworks have been developed. Interestingly, these 2D nanomaterials have found applications in diagnosis and treatment of various diseases including Alzheimer's disease (AD). Although AD is one of the most debilitating neurodegenerative conditions across the globe; unfortunately, there remains a paucity of effective diagnostic and/or therapeutic intervention for it till date. In this scenario, nanomaterial-based biosensors, or therapeutics especially 2D nanostructures are emerging to be promising in this regard. This review summarizes the diagnostic and therapeutic platforms developed for AD using 2D nanostructures. Collectively, it is worth mentioning that these 2D nanomaterials would seemingly provide an alternative and intriguing platform for biomedical interventions.

Expediting Multiple Biological Properties of Limonene and α-Pinene: Main Bioactive Compounds of Pistacia lentiscus L., Essential Oils.

BACKGROUND: Screening new natural molecules with pharmacological and/or cosmetic properties remains a highly sought-after area of research. Moreover, essential oils and volatile compounds have recently garnered significant interest as natural substance candidates. In this study, the volatile components of Pistacia lentiscus L. essential oils (PLEOs) isolated from the fruit and its main compounds, alpha-pinene, and limonene, are investigated for antioxidant, antidiabetic, and dermatoprotective activities. METHODS: In vitro antioxidant activity was investigated using 2,2'-diphenyl-1-picrylhydrazyl (DPPH), fluorescence recovery after photobleaching (FRAP), and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) methods. The antidiabetic and dermatoprotective effects were studied using enzyme inhibitory activities. RESULTS: Antioxidant tests showed that PLEO has the best activity (ranging from 29.64 ± 3.04 to 73.80 ± 3.96 µg/mL) compared to its main selected molecules (ranging from 74 ± 3.72 to 107.23 ± 5.03 µg/mL). The α-glucosidase and α-amylase assays demonstrated that the elements tested have a promising antidiabetic potential with IC50values ranging from 78.03 ± 2.31 to 116.03 ± 7.42 µg/mL and 74.39 ± 3.08 to 112.35 ± 4.92 µg/mL for the α-glucosidase and α-amylase assays, respectively, compared to the standard drug. For the tyrosinase test, we found that the EOs (IC50 = 57.72 ± 2.86 µg/mL) followed by limonene (IC50 = 74.24 ± 2.06 µg/mL) and α-pinene (IC50 = 97.45 ± 5.22 µg/mL) all exhibited greater inhibitory effects than quercetin (IC50 = 246.90 ± 2.54 µg/mL). CONCLUSIONS: Our results suggest that the biological activities of PLEO, as well as its main compounds, make them promising candidates for the development of new strategies aimed at improving dermatoprotection and treating diseases associated with diabetes mellitus and oxidative stress.

The Complexity of the cGAS-STING Pathway in CNS Pathologies.

Neuroinflammation driven by type-I interferons in the CNS is well established to exacerbate the progression of many CNS pathologies both acute and chronic. The role of adaptor protein Stimulator of Interferon Genes (STING) is increasingly appreciated to instigate type-I IFN-mediated neuroinflammation. As an upstream regulator of type-I IFNs, STING modulation presents a novel therapeutic opportunity to mediate inflammation in the CNS. This review will detail the current knowledge of protective and detrimental STING activity in acute and chronic CNS pathologies and the current therapeutic avenues being explored.

STING-Mediated Autophagy Is Protective against H2O2-Induced Cell Death.

Stimulator of interferon genes (STING)-mediated type-I interferon signaling is a well characterized instigator of the innate immune response following bacterial or viral infections in the periphery. Emerging evidence has recently linked STING to various neuropathological conditions, however, both protective and deleterious effects of the pathway have been reported. Elevated oxidative stress, such as neuroinflammation, is a feature of a number of neuropathologies, therefore, this study investigated the role of the STING pathway in cell death induced by elevated oxidative stress. Here, we report that the H2O2-induced activation of the STING pathway is protective against cell death in wildtype (WT) MEFSV40 cells as compared to STING-/- MEF SV40 cells. This protective effect of STING can be attributed, in part, to an increase in autophagy flux with an increased LC3II/I ratio identified in H2O2-treated WT cells as compared to STING-/- cells. STING-/- cells also exhibited impaired autophagic flux as indicated by p62, LC3-II and LAMP2 accumulation following H2O2 treatment, suggestive of an impairment at the autophagosome-lysosomal fusion step. This indicates a previously unrecognized role for STING in maintaining efficient autophagy flux and protecting against H2O2-induced cell death. This finding supports a multifaceted role for the STING pathway in the underlying cellular mechanisms contributing to the pathogenesis of neurological disorders.

STING-mediated type-I interferons contribute to the neuroinflammatory process and detrimental effects following traumatic brain injury.

BACKGROUND: Traumatic brain injury (TBI) represents a major cause of disability and death worldwide with sustained neuroinflammation and autophagy dysfunction contributing to the cellular damage. Stimulator of interferon genes (STING)-induced type-I interferon (IFN) signalling is known to be essential in mounting the innate immune response against infections and cell injury in the periphery, but its role in the CNS remains unclear. We previously identified the type-I IFN pathway as a key mediator of neuroinflammation and neuronal cell death in TBI. However, the modulation of the type-I IFN and neuroinflammatory responses by STING and its contribution to autophagy and neuronal cell death after TBI has not been explored. METHODS: C57BL/6J wild-type (WT) and STING-/- mice (8-10-week-old males) were subjected to controlled cortical impact (CCI) surgery and brains analysed by QPCR, Western blot and immunohistochemical analyses at 2 h or 24 h. STING expression was also analysed by QPCR in post-mortem human brain samples. RESULTS: A significant upregulation in STING expression was identified in late trauma human brain samples that was confirmed in wild-type mice at 2 h and 24 h after CCI. This correlated with an elevated pro-inflammatory cytokine profile with increased TNF-α, IL-6, IL-1ß and type-I IFN (IFN-α and IFN-ß) levels. This expression was suppressed in the STING-/- mice with a smaller lesion volume in the knockout animals at 24 h post CCI. Wild-type mice also displayed increased levels of autophagy markers, LC3-II, p62 and LAMP2 after TBI; however, STING-/- mice showed reduced LAMP2 expression suggesting a role for STING in driving dysfunctional autophagy after TBI. CONCLUSION: Our data implicates a detrimental role for STING in mediating the TBI-induced neuroinflammatory response and autophagy dysfunction, potentially identifying a new therapeutic target for reducing cellular damage in TBI.