Synthesis and anti-proliferative effect of novel 4-Aryl-1, 3-Thiazole-TPP conjugates via mitochondrial uncoupling process.

With the advent of mitochondrial targeting moiety such as triphenlyphosphonium cation (TPP+), targeting mitochondria in cancer cells has become a promising strategy for combating tumors. Herein, a series of novel 4-aryl-1,3-thiazole derivatives linked to TPP+ moiety were designed and synthesized. The cytotoxicity against a panel of four cancer cell lines was evaluated by CCK-8 assay. Most of these compounds exhibited moderate to good inhibitory activity over HeLa, PC-3 and HCT-15 cells while MCF-7 cells were less sensitive to most compounds. Among them, compound 12a exhibited a significant anti-proliferative activity against HeLa cells, and prompted for further investigation. Specifically, 12a decreased mitochondrial membrane potential and enhanced levels of reactive oxygen species (ROS). The flow cytometry analysis revealed that compound 12a could induce apoptosis and cell cycle arrest at G0/G1 phase in HeLa cells. In addition, mitochondrial bioenergetics assay revealed that 12a displayed mild mitochondrial uncoupling effect. Taken together, these findings suggest the therapeutic potential of compound 12a as an antitumor agent targeting mitochondria.

Mitochondrial Respiration Inhibition Suppresses Papillary Thyroid Carcinoma Via PI3K/Akt/FoxO1/Cyclin D1 Pathway.

Background: Papillary thyroid carcinoma (PTC) is the most common thyroid malignancy, but little is known regarding PTC metabolic phenotypes and the effects of mitochondrial activity on PTC progression. The great potential of mitochondria-targeting therapy in cancer treatment promoted us to use tool compounds from a family of Mito-Fu derivatives to investigate how the regulation of mitochondrial respiration affected tumor progression characteristics and molecular changes in PTC. Methods: Mito-Fu L20, a representative of 12 synthetic derivatives, was chosen for mitochondrial inhibition experiments. Sample sections from PTC patients were collected and processed to explore potential molecular alterations in tumor lymph node metastasis (LNM). In vitro analyses were performed using human PTC cell lines (K1 and TPC-1), with the human normal thyroid follicular cell line (Nthy) as a control. K1 cells were injected into nude mice to generate an animal model. The mice were injected with normal saline or Mito-Fu L20 at 20 or 50 mg/kg every other day; their body weights and tumor volumes were also measured over time. To elucidate the resulting metabolic phenotype, we measured oxygen consumption rate (OCR) and extracellular acidification rate (ECAR), cellular adenosine triphosphate (ATP) levels and reactive oxygen species (ROS) production, and mitochondrial membrane potential. Wound healing and Transwell assays, cell cycle assays, real-time fluorescence quantitative PCR, Western blotting, and immunohistochemical staining were performed to explore glycolysis-dominant metabolism in PTC. Results: Cyclin D1 and mitochondrial complex IV were detected in tumor samples from PTC patients with LNM. Mito-Fu L20 showed dose-independent and reversible modulation of mitochondrial respiration in PTC. In addition to mitochondrial dysfunction and early apoptosis, G1/S phase arrest. Notably, reversible mitochondrial inhibition yielded durable suppression of tumor proliferation, migration, and invasion via the PI3K/Akt/FoxO1/Cyclin D1 pathway. In vivo experiments demonstrated that Mito-Fu L20 has a good safety profile and specific restorative effect on mitochondrial activity in the liver. In addition, Mito-Fu L20 showed antitumor effects, alleviated tumor angiogenesis, and improved thyroid function. Conclusion: Reversible inhibition of ATP production and durable suppression of PTC growth indicates that the downregulation of mitochondrial function has a negative impact on tumor progression and LNM via the PI3K/Akt/FoxO1/Cyclin D1 pathway. The results provide new insights into the antitumor potential and clinical translation of mitochondrial inhibitors.

One-Pot Enzymatic Synthesis and Biological Evaluation of Ganglioside GM3 Derivatives as Potential Cancer Immunotherapeutics.

Cancer is a leading cause of death worldwide. Recent research studies have revealed that GM3 derivatives have considerable promise as potential therapeutic agents for cancer. To discover novel GM3 derivatives as potential antitumor agents, a one-pot enzymatic synthesis was established, yielding 14 GM3 derivatives in high total yields (22-41%). Subsequently, the inhibitory activities of GM3 derivatives were assessed by wound-healing assays and Transwell assays and tumor-bearing animal models. Among all the GM3 derivatives, N-12 showed excellent migration and invasion inhibitory effects in cells and marked antitumor activity in C57BL/6 mice. The subsequent analysis of cancer tissues and serum samples revealed that N-12 induces tumor inhibition, which was closely related to immune response. Taken together, N-12 can be further developed as an effective therapeutic for the treatment of cancer. An RNA-sequencing (RNA-seq) analysis was then performed and indicated that the antitumor mechanism of N-12 involved focal adhesion and ECM-receptor interaction signaling pathways.

Discovery of Sortase A covalent inhibitors with benzofuranene cyanide structures as potential antibacterial agents against Staphylococcus aureus.

Sortase A (SrtA) is a cysteine transpeptidase of most gram-positive bacteria that is responsible for the anchoring of many surface protein virulence factors to the cell wall. SrtA ablation has demonstrated to alleviate the infection without affecting the viability of bacteria. Herein, a series of benzofuran cyanide derivatives were synthesized and evaluated. Several compounds exhibited excellent inhibitory activity against SrtA with IC50 values from 3.3 µM to 21.8 µM compared with the known SrtA inhibitor pHMB (IC50 = 130 µM). Ⅲ-1, Ⅲ-15, Ⅲ-34 and V-1 showed potent inhibitory effects on biofilm formation with IC50 values from 2.1 µM to 54.2 µM. Invasion assays showed the four compounds caused a decrease of 4%-24.0% in the uptake of the S. aureus strain by 293T cells. Further assay showed that compound Ⅲ-15 decreased the amount of cell wall-associated protein A by 26.5%. Structure-activity relationship and docking studies demonstrated that the acrylonitrile moiety of the compounds played an important role in enhancing the activity. When the double bond of acrylonitrile changed to single bond, the activity was decreased significantly. This indicates that acrylonitrile, which is a Michael receptor, can inhibit the activity of SrtA by covalent binding effectively to the thiol group of Cys184.

Interaction of tau with HNRNPA2B1 and N6-methyladenosine RNA mediates the progression of tauopathy.

The microtubule-associated protein tau oligomerizes, but the actions of oligomeric tau (oTau) are unknown. We have used Cry2-based optogenetics to induce tau oligomers (oTau-c). Optical induction of oTau-c elicits tau phosphorylation, aggregation, and a translational stress response that includes stress granules and reduced protein synthesis. Proteomic analysis identifies HNRNPA2B1 as a principle target of oTau-c. The association of HNRNPA2B1 with endogenous oTau was verified in neurons, animal models, and human Alzheimer brain tissues. Mechanistic studies demonstrate that HNRNPA2B1 functions as a linker, connecting oTau with N6-methyladenosine (m6A) modified RNA transcripts. Knockdown of HNRNPA2B1 prevents oTau or oTau-c from associating with m6A or from reducing protein synthesis and reduces oTau-induced neurodegeneration. Levels of m6A and the m6A-oTau-HNRNPA2B1 complex are increased up to 5-fold in the brains of Alzheimer subjects and P301S tau mice. These results reveal a complex containing oTau, HNRNPA2B1, and m6A that contributes to the integrated stress response of oTau.

Biological evaluation of mitochondria targeting small molecules as potent anticancer drugs.

Cancer therapy targets specific metabolic pathways or a single gene. This may result in low therapeutic effects due to drug selectivity and drug resistance. Recent studies revealed that the mitochondrial membrane potential and transmembrane permeability of cancerous mitochondria are differed from normal mitochondria. Thus, chemotherapy targeting cancerous mitochondria could be an innovative and competent strategy for cancer therapy. Previously, our work with a novel group of mitochondria targeting small molecules presented promising inhibitory capability toward various cancer cell lines and suppressed adenosine triphosphate (ATP) generation. Therefore, it is critical to understand the anticancer effect and targeting mechanism of these small molecules. This study investigated the inhibitory activity of mitochondria targeting small molecules with human cervical cancer cells - HeLa to further explore their therapeutic potential. HeLa cells were exposed to 10 µM of synthesized compounds and presented elevation in intracellular reactive oxygen species (ROS) level, impaired mitochondrial membrane potential and upregulation of apoptosis as well as necrosis. In vivo, HeLa cell tumor-bearing BALB/c nude mice were treated with mitochondria targeting small molecules for 12 days consecutively. Throughout this chemotherapy study, no deleterious side effects nor the appearance of toxicity was observed. Furthermore, mitochondria targeting small molecules treated groups exhibited significant down-regulation with both tumor volume and tumor weight compared to the Doxorubicin (DOX) treated group. Thus, inhibition of mitochondrial ATP synthesis, activation of intracellular ROS production, down-regulation of mitochondrial membrane potential and upregulation of apoptosis and necrosis rates are the indications of cancer therapy. In this work, we examined the anticancer capability of four mitochondria targeting small molecules in vitro and in vivo, and demonstrated a novel therapeutic approach in cancer therapy with tremendous potential.

Design, synthesis and biological evaluation of novel thiazole-derivatives as mitochondrial targeting inhibitors of cancer cells.

Mitochondria are pivotal energy production sources for cells to maintain necessary metabolism activities. Targeting dysfunctional mitochondrial features has been a hotspot for mitochondrial-related disease researches. Investigation with cancerous mitochondrial metabolism is a continuing concern within tumor therapy. Herein, we set out to assess the anti-cancer activities of a novel family of TPP-thiazole derivatives based on our earlier research on mitochondrial targeting agents. Specifically, we designed and synthesized a series of TPP-thiazole derivatives and revealed by the MTT assay that most synthesized compounds effectively inhibited three cancer cell lines (HeLa, PC3 and MCF-7). After structure modifications, we explored the SAR relationships and identified the most promising compound R13 (IC50 of 5.52 µM) for further investigation. In the meantime, we performed ATP production assay to assess the selected compounds inhibitory effect on HeLa cells energy production. The results displayed the test compounds significantly restrained ATP production of cancer cells. Overall, we have designed and synthesized a series of compounds which exhibited significant cytotoxicity against cancer cells and effectively inhibited mitochondrial energy production.

Structural optimization of pyrazolo[1,5-a]pyrimidine derivatives as potent and highly selective DPP-4 inhibitors.

Our previous discovery of pyrazolo [1,5-a]pyrimidin-7(4H)-one scaffold-based DPP-4 inhibitors yielded two potent compounds b2 (IC50 = 79 nM) and d1 (IC50 = 49 nM) but characterized by cytotoxicity. Herein, with scaffold hopping and fragment-based drug design strategies, highly potent and selective pyrazolo [1,5-a]pyrimidine DPP-4 inhibitors were found featured by reduced or diminished cytotoxicity. Specifically, c24 (IC50 = 2 nM) exhibits a 25 to 40-fold increase of inhibitory activity respect to those of b2 and d1, respectively, 2-fold from Alogliptin (IC50 = 4 nM), and remarkable selectivity over DPP-8 and DPP-9 (>2000 fold). Further docking studies confirmed that the pyrazolo [1,5-a]pyrimidine core interacts with the S1 pocket whereas its substituted aromatic ring interacts with the sub-S1 pocket. The interactive mode in this case resembles that of Alogliptin and Trelagliptin. Further in vivo IPGTT assays in diabetic mice demonstrated that c24 effectively reduces glucose excursion by 48% at the dose of 10 mg/kg, suggesting that c24 is worthy of further development as a potent anti-diabetes agent.

Drug discovery approaches targeting the incretin pathway.

Incretin pathway plays an important role in the development of diabetes medications. Interventions in DPP-4 and GLP-1 receptor have shown remarkable efficacy in experimental and clinical studies and imperatively become one of the most promising therapeutic approaches in the T2DM drug discovery pipeline. Herein, we analyzed the actionmechanismsof DPP-4 and GLP-1 receptor targeting the incretin pathway in T2DM treatment. We gave an insight into the structural requirements for the potent DPP-4 inhibitors and revealed a classification of DPP-4 inhibitors by stressing on the binding modes of these ligands to the enzyme. We then reviewed the drug discovery strategies for the development of peptide and non-peptide GLP-1 receptor agonists (GLP-1 RAs). Furthermore, the drug design strategies for DPP-4 inhibitors and GLP-1R agonists were detailed accurately. This review might provide an efficient evidence for the highly potent and selective DPP-4 inhibitors and the GLP-1 RAs, as novel medicines for patients suffering from T2DM.

Heavy Metal Neurotoxicants Induce ALS-Linked TDP-43 Pathology.

Heavy metals, such as lead, mercury, and selenium, have been epidemiologically linked with a risk of ALS, but a molecular mechanism proving the connection has not been shown. A screen of putative developmental neurotoxins demonstrated that heavy metals (lead, mercury, and tin) trigger accumulation of TDP-43 into nuclear granules with concomitant loss of diffuse nuclear TDP-43. Lead (Pb) and methyl mercury (MeHg) disrupt the homeostasis of TDP-43 in neurons, resulting in increased levels of transcript and increased splicing activity of TDP-43. TDP-43 homeostasis is tightly regulated, and positively or negatively altering its splicing-suppressive activity has been shown to be deleterious to neurons. These changes are associated with the liquid-liquid phase separation of TDP-43 into nuclear bodies. We show that lead directly facilitates phase separation of TDP-43 in a dose-dependent manner in vitro, possibly explaining the means by which lead treatment results in neuronal nuclear granules. Metal toxicants also triggered the accumulation of insoluble TDP-43 in cultured cells and in the cortices of exposed mice. These results provide novel evidence of a direct mechanistic link between heavy metals, which are a commonly cited environmental risk of ALS, and molecular changes in TDP-43, the primary pathological protein accumulating in ALS.