Investigations of Ni(II)Cysteine-Tyrosine Dithiocarbamate Complex: Synthesis, Characterization, Molecular Docking, Molecular Dynamic, and Anticancer Activity on MCF-7 Breast Cancer Cell Line.

OBJECTIVE: Breast cancer ranks second in terms of the highest number of cancer deaths for women worldwide and is one of the leading causes of death from cancer in women. The drug that is often used for chemotherapy is cisplatin. However, cisplatin drugs have a number of problems, including lack of selectivity, unwanted side effects, resistance, and toxicity in the body. In this work, we investigated Ni(II) cysteine-tyrosine dithiocarbamate complex against breast cancer. METHODS: Research on the new complex compound Ni(II) cysteine-tyrosine dithiocarbamate have several stages including synthesis, characterization, in-silico and in-vitro testing of MCF-7 cells for anticancer drugs. The synthesis involved reacting cysteine, CS2, KOH and tyrosine with Mn metal. The new complex compound Ni(II) cysteine-tyrosine dithiocarbamate has been synthesized, characterized, and tested in vitro MCF-7 cells for anticancer drugs. Characterization tests such as melting point, conductivity, SEM-EDS, UV Vis, XRD, and FT-IR spectroscopy have been carried out. RESULT: The synthesis yielded a 60,16%, conversion with a melting point of 216-218 oC and a conductivity value of 0.4 mS/cm. In vitro test results showed morphological changes (apoptosis) in MCF-7 cancer cells starting at a sample concentration of 250 µg/mL and an IC50 value of 618.40 µg/mL. Molecular docking study of Ni(II) cysteine-tyrosine dithiocarbamate complex identified with 4,4',4''-[(2R)-butane-1,1,2-triyl]triphenol - Estrogen α showing active site with acidic residue amino E323, M388, L387, G390 and I389. Hydrophobic and hydrophobic bonds are seen in Ni(II) cysteine-tyrosine dithiocarbamate - Estrogen α has a binding energy of -80.9429 kJ /mol. CONCLUSION: there were 5 residues responsible for maintaining the ligand binding stable. The compound had significant Hbond contact intensity, however, it was not strong enough to make a significant anticancer effect. Though the synthesized compound shows low bioactivity, this research is expected to give valuable insight into the effect of molecular structure on anticancer activity.

TTLL12 has a potential oncogenic activity, suppression of ligation of nitrotyrosine to the C-terminus of detyrosinated α-tubulin, that can be overcome by molecules identified by screening a compound library.

Tubulin tyrosine ligase 12 (TTLL12) is a promising target for therapeutic intervention since it has been implicated in tumour progression, the innate immune response to viral infection, ciliogenesis and abnormal cell division. It is the most mysterious of a fourteen-member TTL/TTLL family, since, although it is the topmost conserved in evolution, it does not have predicted enzymatic activities. TTLL12 seems to act as a pseudo-enzyme that modulates various processes indirectly. Given the need to target its functions, we initially set out to identify a property of TTLL12 that could be used to develop a reliable high-throughput screening assay. We discovered that TTLL12 suppresses the cell toxicity of nitrotyrosine (3-nitrotyrosine) and its ligation to the C-terminus of detyrosinated α-tubulin (abbreviated to ligated-nitrotyrosine). Nitrotyrosine is produced by oxidative stress and is associated with cancer progression. Ligation of nitrotyrosine has been postulated to be a check-point induced by excessive cell stress. We found that the cytotoxicities of nitrotyrosine and tubulin poisons are independent of one another, suggesting that drugs that increase nitrotyrosination could be complementary to current tubulin-directed therapeutics. TTLL12 suppression of nitrotyrosination of α-tubulin was used to develop a robust cell-based ELISA assay that detects increased nitrotyrosination in cells that overexpress TTLL12 We adapted it to a high throughput format and used it to screen a 10,000 molecule World Biological Diversity SETTM collection of low-molecular weight molecules. Two molecules were identified that robustly activate nitrotyrosine ligation at 1 µM concentration. This is the pioneer screen for molecules that modulate nitrotyrosination of α-tubulin. The molecules from the screen will be useful for the study of TTLL12, as well as leads for the development of drugs to treat cancer and other pathologies that involve nitrotyrosination.

Glycoprotein IIb/IIIa inhibitors in the treatment of thromboembolic events related to endovascular treatment of cerebral aneurysms-systematic review and meta-analysis.

BACKGROUND AND AIMS: Thromboembolism complication is considered the most common complication associated with the treatment of endovascular. This systematic review and meta-analysis aimed to assess the studies investigating the effect of glycoprotein IIb/IIIa inhibitor agents on thromboembolic complications during endovascular aneurysm coiling. MATERIALS AND METHODS: This systematic review investigated the outcome of the use of three glycoprotein IIb/IIIa inhibitor agents (ie abciximab, tirofiban, and eptifibatide) on the thromboembolic complications during endovascular aneurysm coiling. The electronic databases of PubMed, Web of Science, Scopus, and Medline were searched up to 25 June 2021, using the keywords "Abciximab," "Tirofiban," and "Eptifibatide" incombination with "Thromboembolism Complication," "Aneurysms," and "Endovascular Aneurysm Coiling." RESULTS: A total of 21 articles were found to be eligible and included in this review. The rates of complete and partial recanalization were estimated to be 56% and 92% in patients who underwent abciximab and tirofiban therapy, respectively. Rupture aneurysms were found in the majority of patients. In general, the mortality rate of the patients treated for thromboembolic complications during endovascular treatment of cerebral aneurysms with glycoprotein IIb/IIIa inhibitors was found to be 4.8% (CI 95%:0.027-0.067; p < .005). The average remission rate in studies investigating thromboembolism was 91% (CI 95%:0.88-0.95, I2 : 65.65/p < .001). CONCLUSION: Based on the obtained results, a higher mean rate of complete recanalization by eptifibatide was found in studies in which abciximab or tirofiban were used, compared to other mentioned agents. Moreover, the amount of hemorrhage was reported to be less after using tirofiban rather than abciximab.

Arsenic-induced IGF-1 signaling impairment and neurite shortening: The protective roles of IGF-1 through the PI3K/Akt axis.

We recently reported that arsenic caused insulin resistance in differentiated human neuroblastoma SH-SY5Y cells. Herein, we further investigated the effects of sodium arsenite on IGF-1 signaling, which shares downstream signaling with insulin. A time-course experiment revealed that sodium arsenite began to decrease IGF-1-stimulated Akt phosphorylation on Day 3 after treatment, indicating that prolonged sodium arsenite treatment disrupted the neuronal IGF-1 response. Additionally, sodium arsenite decreased IGF-1-stimulated tyrosine phosphorylation of the IGF-1 receptor ß (IGF-1Rß) and its downstream target, insulin receptor substrate 1 (IRS1). These results suggested that sodium arsenite impaired the intrinsic tyrosine kinase activity of IGF-1Rß, ultimately resulting in a reduction in tyrosine-phosphorylated IRS1. Sodium arsenite also reduced IGF-1 stimulated tyrosine phosphorylation of insulin receptor ß (IRß), indicating the potential inhibition of IGF-1R/IR crosstalk by sodium arsenite. Interestingly, sodium arsenite also induced neurite shortening at the same concentrations that caused IGF-1 signaling impairment. A 24-h IGF-1 treatment partially rescued neurite shortening caused by sodium arsenite. Moreover, the reduction in Akt phosphorylation by sodium arsenite was attenuated by IGF-1. Inhibition of PI3K/Akt by LY294002 diminished the protective effects of IGF-1 against sodium arsenite-induced neurite retraction. Together, our findings suggested that sodium arsenite-impaired IGF-1 signaling, leading to neurite shortening through IGF-1/PI3K/Akt.

Leptin and energy balance: exploring Leptin's role in the regulation of energy intake and energy expenditure.

Leptin is a tonic appetite-regulating hormone, which is integral for the long-term regulation of energy balance. The current evidence suggests that the typical orexigenic or anorexigenic response of many of these appetite-regulating hormones, most notably ghrelin and cholecystokinin (CCK), require leptin to function whereas glucagon-like peptide-1 (GLP-1) is required for leptin to function, and these responses are altered when leptin injection or gene therapy is administered in combination with these same hormones or respective agonists. The appetite-regulatory pathway is complex, thus peptide tyrosine tyrosine (PYY), brain-derived neurotrophic factor (BDNF), orexin-A (OXA), and amylin also maintain ties to leptin, however these are less well understood. While reviews to date have focused on the existing relationships between leptin and the various neuropeptide modulators of appetite within the central nervous system (CNS) or it's role in thermogenesis, no review paper has synthesised the information regarding the interactions between appetite-regulating hormones and how leptin as a chronic regulator of energy balance can influence the acute appetite-regulatory response. Current evidence suggests that potential relationships exist between leptin and the circulating peripheral appetite hormones ghrelin, GLP-1, CCK, OXA and amylin to exhibit either synergistic or opposing effects on appetite inhibition. Though more research is warranted, leptin appears to be integral in both energy intake and energy expenditure. More specifically, functional leptin receptors appear to play an essential role in these processes.

Prostaglandin E2 Exposure Disrupts E-Cadherin/Caveolin-1-Mediated Tumor Suppression to Favor Caveolin-1-Enhanced Migration, Invasion, and Metastasis in Melanoma Models.

Caveolin-1 (CAV1) is a membrane-bound protein that suppresses tumor development yet also promotes metastasis. E-cadherin is important in CAV1-dependent tumor suppression and prevents CAV1-enhanced lung metastasis. Here, we used murine B16F10 and human A375 melanoma cells with low levels of endogenous CAV1 and E-cadherin to unravel how co-expression of E-cadherin modulates CAV1 function in vitro and in vivo in WT C57BL/6 or Rag-/- immunodeficient mice and how a pro-inflammatory environment generated by treating cells with prostaglandin E2 (PGE2) alters CAV1 function in the presence of E-cadherin. CAV1 expression augmented migration, invasion, and metastasis of melanoma cells, and these effects were abolished via transient co-expression of E-cadherin. Importantly, exposure of cells to PGE2 reverted the effects of E-cadherin expression and increased CAV1 phosphorylation on tyrosine-14 and metastasis. Moreover, PGE2 administration blocked the ability of the CAV1/E-cadherin complex to prevent tumor formation. Therefore, our results support the notion that PGE2 can override the tumor suppressor potential of the E-cadherin/CAV1 complex and that CAV1 released from the complex is phosphorylated on tyrosine-14 and promotes migration/invasion/metastasis. These observations provide direct evidence showing how a pro-inflammatory environment caused here via PGE2 administration can convert a potent tumor suppressor complex into a promoter of malignant cell behavior.

Metabolic engineering strategies for naringenin production enhancement in Streptomyces albidoflavus J1074.

BACKGROUND: Naringenin is an industrially relevant compound due to its multiple pharmaceutical properties as well as its central role in flavonoid biosynthesis. RESULTS: On our way to develop Streptomyces albidoflavus J1074 as a microbial cell factory for naringenin production, we have significantly increased the yields of this flavanone by combining various metabolic engineering strategies, fermentation strategies and genome editing approaches in a stepwise manner. Specifically, we have screened different cultivation media to identify the optimal production conditions and have investigated how the additive feeding of naringenin precursors influences the production. Furthermore, we have employed genome editing strategies to remove biosynthetic gene clusters (BGCs) associated with pathways that might compete with naringenin biosynthesis for malonyl-CoA precursors. Moreover, we have expressed MatBC, coding for a malonate transporter and an enzyme responsible for the conversion of malonate into malonyl-CoA, respectively, and have duplicated the naringenin BGC, further contributing to the production improvement. By combining all of these strategies, we were able to achieve a remarkable 375-fold increase (from 0.06 mg/L to 22.47 mg/L) in naringenin titers. CONCLUSION: This work demonstrates the influence that fermentation conditions have over the final yield of a bioactive compound of interest and highlights various bottlenecks that affect production. Once such bottlenecks are identified, different strategies can be applied to overcome them, although the efficiencies of such strategies may vary and are difficult to predict.

Effects of Dietary Cystine and Tyrosine Supplementation on Melanin Synthesis in the Pacific Oyster (Crassostrea gigas).

Melanogenesis is a multistep process to produce melanin for dark pigmentation in skin coloration. Previous studies in vertebrates demonstrated that cystine and tyrosine amino acids are involved in the melanin synthesis. However, very little is known about the melanogenesis in bivalve. In this study, cystine supplementation for 30 days significantly upregulated the expression of CgB-aat1, CgCbs and CgTyr and pheomelanin content in the Pacific oyster Crassostrea gigas. Transmission electron microscope (TEM) results revealed more melanosomes in the connective tissue and melanin granules were secreted in epithelium of mantle. In contrast, tyrosine supplementation had no clear effect on melanogenesis except the gene expression changes of CgB-aat1 and CgCbs. In addition, prolonged supplementation of cystine or tyrosine for 60 days had a negative impact on melanogenesis. Indeed, after 60 days, expression of most of the melanin synthesis-related genes under study was decreased, and melanin content was significantly reduced, indicating that cystine and tyrosine might inhibit production of eumelanin and pheomelanin, respectively. In addition, in vitro analysis using primary cell culture from mantle tissue indicated that incubation with cystine, tyrosine, or B-AAT1 polypeptide, CBS/TYR recombinant proteins induced the increase of CgB-aat1 and CgCbs expression in a dose-dependent manner, suggesting the presence of a regulatory network in response to cystine and tyrosine amino acids intakes in pheomelanin synthesis-related gene expression. Taken together, these data indicate that cystine-CgB-aat1-CgCbs-CgTyr axis is a potential regulator of the pheomelanin biosynthesis pathway, and thus plays an important role in the mantle pigmentation in C. gigas. This work provides a new clue for selective cultivation of oyster strains with specific shell colors in bivalve breeding.

TLR4 phosphorylation at tyrosine 672 activates the ERK/c-FOS signaling module for LPS-induced cytokine responses in macrophages.

TLRs engage numerous adaptor proteins and signaling molecules, enabling a complex series of post-translational modifications (PTMs) to mount inflammatory responses. TLRs themselves are post-translationally modified following ligand-induced activation, with this being required to relay the full spectrum of proinflammatory signaling responses. Here, we reveal indispensable roles for TLR4 Y672 and Y749 phosphorylation in mounting optimal LPS-inducible inflammatory responses in primary mouse macrophages. LPS promotes phosphorylation at both tyrosine residues, with Y749 phosphorylation being required for maintenance of total TLR4 protein levels and Y672 phosphorylation exerting its pro-inflammatory effects more selectively by initiating ERK1/2 and c-FOS phosphorylation. Our data also support a role for the TLR4-interacting membrane proteins SCIMP and the SYK kinase axis in mediating TLR4 Y672 phosphorylation to permit downstream inflammatory responses in murine macrophages. The corresponding residue in human TLR4 (Y674) is also required for optimal LPS signaling responses. Our study, thus, reveals how a single PTM on one of the most widely studied innate immune receptors orchestrates downstream inflammatory responses.

Classic Phytochemical Antioxidant and Lipoxygenase Inhibitor, Nordihydroguaiaretic Acid, Activates Phospholipase D through Oxidant Signaling and Tyrosine Phosphorylation Leading to Cytotoxicity in Lung Vascular Endothelial Cells.

Nordihydroguaiaretic acid (NDGA), a dicatechol and phytochemical polyphenolic antioxidant and an established inhibitor of human arachidonic acid (AA) 5-lipoxygenase (LOX) and 15-LOX, is widely used to ascertain the role of LOXs in vascular endothelial cell (EC) function. As the modulatory effect of NDGA on phospholipase D (PLD), an important lipid signaling enzyme in ECs, thus far has not been reported, here we have investigated the modulation of PLD activity and its regulation by NDGA in the bovine pulmonary artery ECs (BPAECs). NDGA induced the activation of PLD (phosphatidic acid formation) in cells in a dose- and time-dependent fashion that was significantly attenuated by iron chelator and antioxidants. NDGA induced the formation of reactive oxygen species (ROS) in cells in a dose- and time-dependent manner as evidenced from fluorescence microscopy and fluorimetry of ROS and electron paramagnetic resonance spectroscopy of oxygen radicals. Also, NDGA caused a dose-dependent loss of intracellular glutathione (GSH) in BPAECs. Protein tyrosine kinase (PTyK)-specific inhibitors significantly attenuated NDGA-induced PLD activation in BPAECs. NDGA also induced a dose- and time-dependent phosphorylation of tyrosine in proteins in cells. NDGA caused in situ translocation and relocalization of both PLD1 and PLD2 isoforms, in a time-dependent fashion. Cyclooxygenase (COX) inhibitors were ineffective in attenuating NDGA-induced PLD activation in BPAECs, thus ruling out the activation of COXs by NDGA. NDGA inhibited the AA-LOX activity and leukotriene C4 (LTC4) formation in cells. On the other hand, the 5-LOX-specific inhibitors, 5, 8, 11, 14-eicosatetraynoic acid and kaempferol, were ineffective in activating PLD in BPAECs. Antioxidants and PTyK-specific inhibitors effectively attenuated NDGA cytotoxicity in BPAECs. The PLD-specific inhibitor, 5-fluoro-2-indolyl deschlorohalopemide (FIPI), significantly attenuated and protected against the NDGA-induced PLD activation and cytotoxicity in BPAECs. For the first time, these results demonstrated that NDGA, the classic phytochemical polyphenolic antioxidant and LOX inhibitor, activated PLD causing cytotoxicity in ECs through upstream oxidant signaling and protein tyrosine phosphorylation.

A JAK tyrosine kinase and pseudokinase Co-inhibition strategy combines enhanced potency and on-demand activation.

Janus tyrosine kinase (JAK) inhibitors have been on the market for several years, but their use is limited by drug resistance and intolerable side effects. Herein, we propose a novel strategy of JAK tyrosine kinase (TK) and pseudokinase (PK) domain co-inhibition system to consolidate robust JAK inhibition and on-demand activation. A photoexcited prodrug PAT-SIL-TG-1&AT exhibits the synergy effects of TK-PK co-inhibition and enable the spatiotemporal control of JAK2 signaling. The hypoxia-activated prodrug HAT-SIL-TG-1&AT significantly inhibited HEL cells proliferation and downregulated phosphorylated STAT3/5 under hypoxic conditions. Importantly, HAT-SIL-TG-1&AT showed synergistic antitumor effects and selectively inhibited the JAK-STAT signaling in tumor tissues in vivo. This work demonstrates a viable solution to achieve superior JAK2 inhibition, and provides an inspiration for other kinases containing PK domain.

Insights into the Transport Cycle of LAT1 and Interaction with the Inhibitor JPH203.

The large Amino Acid Transporter 1 (LAT1) is an interesting target in drug discovery since this transporter is overexpressed in several human cancers. Furthermore, due to its location in the blood-brain barrier (BBB), LAT1 is interesting for delivering pro-drugs to the brain. In this work, we focused on defining the transport cycle of LAT1 using an in silico approach. So far, studies of the interaction of LAT1 with substrates and inhibitors have not considered that the transporter must undergo at least four different conformations to complete the transport cycle. We built outward-open and inward-occluded conformations of LAT1 using an optimized homology modelling procedure. We used these 3D models and the cryo-EM structures in outward-occluded and inward-open conformations to define the substrate/protein interaction during the transport cycle. We found that the binding scores for the substrate depend on the conformation, with the occluded states as the crucial steps affecting the substrate affinity. Finally, we analyzed the interaction of JPH203, a high-affinity inhibitor of LAT1. The results indicate that conformational states must be considered for in silico analyses and early-stage drug discovery. The two built models, together with the available cryo-EM 3D structures, provide important information on the LAT1 transport cycle, which could be used to speed up the identification of potential inhibitors through in silico screening.

Antiproliferative and Antiprostate Cancer Activities of Heterocyclic Compounds Derived from Cyclohexane-1,4-dione.

2-Amino-6-oxo-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbonitrile (3) was prepared from the reaction of cyclohexane-1,4-dione with elemental sulfur and malononitrile in 1,4-dioxane and triethylamine as catalyst. The latter compound reacted with triethyl orthoformate and either malononitrile or ethyl cyanoacetate in 1,4-dioxane in the presence of triethylamine to produce 4H-thieno[2,3-f]chromene derivatives 10a,b. In addition, fused pyran and pyridine derivatives were synthesized starting from compound 3. The cytotoxicity of the synthesized compounds was studied on six cancer cell lines together with c-Met kinase and PC-3 cell line. The most active compounds were tested against five tyrosine kinases and Pim-1 kinase, most of which showed strong inhibition, encouraging further work.

Peficitinib inhibits fibroblast-like synoviocyte activation and angiogenic vascular endothelial tube formation via inhibitory effects on PDGF and VEGF signaling in addition to JAK.

PURPOSE: Peficitinib and tofacitinib are known to suppress inflammation in rheumatoid arthritis (RA) by inhibiting Janus kinases (JAKs). However, these effects on tyrosine kinases other than JAKs have not yet been well investigated. We evaluated the effects of peficitinib and tofacitinib on platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) receptor tyrosine kinases (RTKs) and on the activation of fibroblast-like synoviocytes (FLSs) and endothelial cells, main pathological causes of RA. METHODS: Peficitinib and tofacitinib were tested in PDGF and VEGF RTK assays. We then used FLSs derived from RA patient (RA-FLSs) and human umbilical vein endothelial cells (HUVECs) to study the effects of peficitinib and tofacitinib on PDGF- and VEGF-induced signal transduction and on the activation of RA-FLSs and endothelial cell tube formation. FINDINGS: Peficitinib, not tofacitinib, inhibited both PDGF and VEGF RTKs in addition to JAKs in cell-free assay system. Peficitinib and tofacitinib attenuated PDGF- and VEGF-induced intracellular signal transduction pathways in RA-FLSs and HUVECs to varying degrees. Only peficitinib potently inhibited PDGF-induced secretion of interleukin-6, VEGF, and matrix metalloproteinase-3 in RA-FLSs, and endothelial cell tube formation by HUVECs. CONCLUSION: Peficitinib may improve RA through inhibition of PDGF and VEGF signal transduction, in addition to JAK inhibition.

Decorating hexahistidine-metal assemblies with tyrosine enhances the ability of proteins to pass through corneal biobarriers.

In recent decades, the use of protein drugs has increased dramatically for almost every clinical indication, including autoimmunity and cancer infection, given their high specificity and limited side effects. However, their easy deactivation by the surrounding microenvironment and limited ability to pass through biological barriers pose large challenges to the use of these agents for therapeutic effects; these deficits could be greatly improved by nanodelivery using platforms with suitable physicochemical properties. Here, to assess the effect of the hydrophobicity of nanoparticles on their ability to penetrate biological barriers, the hydrophobic amino acid tyrosine (Y) was decorated onto hexahistidine peptide, and two nanosized YHmA and HmA particles were generated, in which Avastin (Ava, a protein drug) was encapsulated by a coassembly strategy. In vitro and in vivo tests demonstrated that these nanoparticles effectively retained the bioactivity of Ava and protected Ava from proteinase K hydrolysis. Importantly, YHmA displayed a considerably higher affinity to the ocular surface than HmA, and YHmA also exhibited the ability to transfer proteins across the barriers of the anterior segment, which greatly improved the bioavailability of the encapsulated Ava and produced surprisingly good therapeutic outcomes in a model of corneal neovascularization. STATEMENT OF SIGNIFICANCE: Improving the ability to penetrate tissue barriers and averting inactivation caused by surrounding environments, are the keys to broaden the application of protein drugs. By decorating hydrophobic amino acid, tyrosine (Y), on hexahistidine peptide, YHmA encapsulated protein drug Ava with high efficiency by co-assembly strategy. YHmA displayed promising ability to maintain bioactivity of Ava during encapsulation and delivery, and protected Ava from proteinase K hydrolysis. Importantly, YHmA transferred Ava across the corneal epithelial barrier and greatly improved its bioavailability, producing surprisingly good therapeutic outcomes in a model of corneal neovascularization. Our results contributed to not only the strategy to overcome shortcomings of protein drugs, but also suggestion on hydrophobicity as a nonnegligible factor in nanodrug penetration through biobarriers.

Protein tyrosine kinase inhibitor resistance in malignant tumors: molecular mechanisms and future perspective.

Protein tyrosine kinases (PTKs) are a class of proteins with tyrosine kinase activity that phosphorylate tyrosine residues of critical molecules in signaling pathways. Their basal function is essential for maintaining normal cell growth and differentiation. However, aberrant activation of PTKs caused by various factors can deviate cell function from the expected trajectory to an abnormal growth state, leading to carcinogenesis. Inhibiting the aberrant PTK function could inhibit tumor growth. Therefore, tyrosine kinase inhibitors (TKIs), target-specific inhibitors of PTKs, have been used in treating malignant tumors and play a significant role in targeted therapy of cancer. Currently, drug resistance is the main reason for limiting TKIs efficacy of cancer. The increasing studies indicated that tumor microenvironment, cell death resistance, tumor metabolism, epigenetic modification and abnormal metabolism of TKIs were deeply involved in tumor development and TKI resistance, besides the abnormal activation of PTK-related signaling pathways involved in gene mutations. Accordingly, it is of great significance to study the underlying mechanisms of TKIs resistance and find solutions to reverse TKIs resistance for improving TKIs efficacy of cancer. Herein, we reviewed the drug resistance mechanisms of TKIs and the potential approaches to overcome TKI resistance, aiming to provide a theoretical basis for improving the efficacy of TKIs.

Differential sensitivity of metabolic pathways in sugar beet roots to combined salt, heat, and light stress.

Plants in nature commonly encounter combined stress scenarios. The response to combined stressors is often unpredictable from the response to single stresses. To address stress interference in roots, we applied salinity, heat, and high light to hydroponically grown sugar beet. Two main patterns of metabolomic acclimation were apparent. High salt of 300 mM NaCl considerably lowered metabolite amounts, for example, those of most amino acids, γ-amino butyric acid (GABA), and glucose. Very few metabolites revealed the opposite trend with increased contents at high salts, mostly organic acids such as citric acid and isocitric acid, but also tryptophan, tyrosine, and the compatible solute proline. High temperature (31°C vs. 21°C) also frequently lowered root metabolite pools. The individual effects of salinity and heat were superimposed under combined stress. Under high light and high salt conditions, there was a significant decline in root chloride, mannitol, ribulose 5-P, cysteine, and l-aspartate contents. The results reveal the complex interaction pattern of environmental parameters and urge researchers to elaborate in much more detail and width on combinatorial stress effects to bridge work under controlled growth conditions to growth in nature, and also to better understand acclimation to the consequences of climate change.

Interfering B cell receptor signaling via SHP-1/p-Lyn axis shows therapeutic potential in diffuse large B-cell lymphoma.

BACKGROUND: Diffuse large B cell lymphoma (DLBCL) is an aggressive and molecularly heterogeneous non-Hodgkin's lymphoma. The B cell receptor (BCR) signaling pathway in DLBCL emerges as a new drug target. Protein phosphatase SHP-1 negatively regulates several oncogenic tyrosine kinases and plays a tumor suppressive role. METHODS: The direct SHP-1 agonists were used to evaluate the potential therapeutic implication of SHP-1 in DLBCL. Immunohistochemical staining for SHP-1 was quantified by H-score. The SHP-1 phosphatase activity was determined using tyrosine phosphatase assay. In vitro studies, including MTT, western blot analysis and cell apoptosis, were utilized to examined biological functions of SHP-1. RESULTS: Oral administration of SHP-1 agonist showed the potent anti-tumor effects compared to a selective Bruton's tyrosine kinase (BTK) inhibitor ibrutinib in mice bearing U2932 xenografts. SHP-1 agonist increased SHP-1 activity as well as downregulated p-Lyn in vivo. Here, we demonstrated that immunohistochemical staining for SHP-1 expression was positive in 76% of DLBCL samples. SHP-1 agonist exerted anti-proliferative and apoptotic effects compared with ibrutinib in DLBCL cells. Mechanistically, SHP-1 agonist decreased BCR signaling, especially p-Lyn, and led to apoptosis. CONCLUSIONS: These data suggest that SHP-1 negatively regulates phosphorylation of Lyn, and targeting SHP-1/p-Lyn using SHP-1 agonist has therapeutic potential for treatment of DLBCL.

Tyrosine phosphatase SHP2 in ovarian granulosa cells balances follicular development by inhibiting PI3K/AKT signaling.

In mammals, the growth and maturation of oocytes within growing follicles largely depends on ovarian granulosa cells (GCs) in response to gonadotropin stimulation. Many signals have been shown to regulate GC proliferation and apoptosis. However, whether the tyrosine phosphatase SHP2 is involved remains unclear. In this study, we identified the crucial roles of SHP2 in modulating GC proliferation and apoptosis. The production of both mature oocytes and pups was increased in mice with Shp2 specifically deleted in ovarian GCs via Fshr-Cre. Shp2 deletion simultaneously promoted GC proliferation and inhibited GC apoptosis. Furthermore, Shp2 deficiency promoted, while Shp2 overexpression inhibited, the proliferation of cultured primary mouse ovarian GCs and the human ovarian granulosa-like tumor cell line KGN in vitro. Shp2 deficiency promoted follicule-stimulating hormone (FSH)-activated phosphorylation of AKT in vivo. SHP2 deficiency reversed the inhibitory effect of hydrogen peroxide (H2O2) on AKT activation in KGN cells. H2O2 treatment promoted the interaction between SHP2 and the p85 subunit of PI3K in KGN cells. Therefore, SHP2 in GCs may act as a negative modulator to balance follicular development by suppressing PI3K/AKT signaling. The novel function of SHP2 in modulating proliferation and apoptosis of GCs provides a potential therapeutic target for the clinical treatment of follicle developmental dysfunction.

Xenoacremones D-H, Bioactive Tyrosine-decahydrofluorene Analogues from the Plant-Derived Fungus Xenoacremonium sinensis.

Five novel tyrosine-decahydrofluorene analogues, xenoacremones D−H (1−5), each bearing a fused 6/5/6 tricarbocyclic core and a 13-membered para-cyclophane ring system, were isolated from the endophytic fungus Xenoacremonium sinensis. Compound 1 was a novel polyketide synthase−nonribosomal peptide synthetase (PKS−NRPS) tyrosine-decahydrofluorene hybrid containing a 6/5/6/6/5 ring system. Their structures were elucidated from comprehensive spectroscopic analysis and electronic circular dichroism (ECD) calculations. All compounds were evaluated for their inhibitory activities on LPS-induced NO production in macrophages and their cytotoxicities against the NB4 and U937 cell lines. Compounds 3 and 5 exhibited potent anti-inflammatory activities in vitro. Compounds 1 and 3−5 displayed significant antiproliferative activity against the tumor cell lines (IC50 < 20 µM).