Discovery of RGT-018: a Potent, Selective and Orally Bioavailable SOS1 Inhibitor for KRAS-driven Cancers.

KRAS is the most frequently dysregulated oncogene with high prevalence in NSCLC, colorectal cancer, and pancreatic cancer. FDA-approved sotorasib and adagrasib provide breakthrough therapies for cancer patients with KRASG12C mutation. However, there is still high unmet medical need for new agents targeting broader KRAS-driven tumors. An emerging and promising opportunity is to develop a pan KRAS inhibitor by suppressing the upstream protein SOS1. SOS1 is a key activator of KRAS and facilitates the conversion of GDP-bound KRAS state to GTP-bound KRAS state. Binding to its catalytic domain, small molecule SOS1 inhibitor has demonstrated the ability to suppress KRAS activation and cancer cell proliferation. RGT-018, a potent and selective SOS1 inhibitor, was identified with optimal drug-like properties. In vitro, RGT-018 blocked the interaction of KRAS:SOS1 with single digit nM potency and is highly selective against SOS2. RGT-018 inhibited KRAS signaling and the proliferation of a broad spectrum of KRAS-driven cancer cells as a single agent in vitro. Further enhanced anti-proliferation activity was observed when RGT-018 was combined with MEK, KRASG12C, EGFR or CDK4/6 inhibitors. Oral administration of RGT-018 inhibited tumor growth and suppressed KRAS signaling in tumor xenografts in vivo. Combination with MEK or KRASG12C inhibitors led to significant tumor regression. Furthermore, RGT-018 overcame the resistance to the approved KRASG12C inhibitors caused by clinically acquired KRAS mutations either as a single agent or in combination. RGT-018 displayed promising pharmacological properties for combination with targeted agents to treat a broader KRAS-driven patient population.

Construction of a MnO2/Crudlan composite hydrogel and its killing effect on melanoma B16-F10 cells combined with photothermal therapy / 中国肿瘤生物治疗杂志

@#[摘 要] 目的：构建负载二氧化锰（MnO2）纳米颗粒的可得然（Cur）复合水凝胶MnO2@Cur（简称MGel），研究其对黑色素瘤B16-F10细胞的杀伤效果。方法：采用热诱导法制备Cur水凝胶（Gel），物理负载MnO2构建MGel，表征其宏观和微观形貌，检测其机械性能、降解性能以及光热转换性能等理化性能，并研究其联合PTT对小鼠皮肤黑色素瘤B16-F10细胞的光热杀伤效果。结果：MGel具有优异的机械和可降解性能，抗拉伸强度达（127.97±3.60）kPa、抗压缩强度达（151.44±5.23）kPa，28 d降解率约58.17%。MGel负载MnO2纳米片（粒径约180 nm）获得优异的光热转换性能，负载1.0 mg/mL MnO2的MGel在1.0 W/cm2的808 nm NIR光照4 min后到达最高温度50 ℃。细胞毒性实验和Calcein-AM/PI荧光双染色实验表明，MGel联合PTT有效杀伤B16-F10黑色素瘤细胞，NIR光照使得MGel组细胞存活率降低至（4.68±0.66）%（P<0.000 1）。结论：MGel复合水凝胶具备优异的机械性能、可降解性能以及光热转换性能，其联合PTT能有效杀伤肿瘤细胞，可能成为一种有效治疗黑色素瘤的新手段。

MicroRNA828 negatively regulates lignin biosynthesis in stem of Populus tomentosa through MYB targets.

Lignin biosynthesis in the sclerenchyma cells is strictly controlled by a complex network of genetic and environmental signals. In the last decades, the transcriptional regulation of lignin synthesis in woody species has been established. However, the role of microRNA-mediated post-transcriptional modulation in secondary cell wall biosynthesis remains poorly understood. Here, we identified a microRNA, miR828, involved in the regulation specific to lignin biosynthesis during stem development in Populus tomentosa Carr. miR828 is preferentially expressed in the secondary vascular tissues during stem development. Two MYB genes (MYB171 and MYB011) were validated as direct targets of miR828 by degradome analysis and green fluorescent protein signal detection. Overexpression of miR828 in poplar downregulated genes for lignin biosynthesis, resulting in reduced lignin content in cell walls. Conversely, suppression of miR828 in plants by the short tandem target mimics elevated the expression of lignin biosynthetic genes and increased lignin deposition. We further revealed that poplar MYB171, as the most abundant miR828 target in the stem, is a positive regulator for lignin biosynthesis. Transient expression assays showed that both MYB171 and MYB011 activated PAL1 and CCR2 transcription, whereas the introduction of miR828 significantly suppressed their expression that was induced by MYB171 or MYB011. Collectively, our results demonstrate that the miR828-MYBs module precisely regulates lignin biosynthesis during the stem development in P. tomentosa through transcriptional and post-transcriptional manners.

Controlled release of resveratrol and xanthohumol via coaxial electrospinning fibers.

Synergistic delivery of two drugs is a desirable choice to overcome drug resistance. Resveratrol (RES) and xanthohumol (XAN) which are both new drugs originated from plants exhibit great potential in the treatment of cancer, but there are few studies on combining them in a delivery system. In this work, a new core/shell fiber mesh containing RES and XAN was designed out via coaxial electrospinning, and the effect of drug content on the medicated fibers was discovered. RES/polyethylene oxide (PEO) could be well combined with XAN/Poly(lactide-glycolide) (PLGA) to make core/shell fibers, but fibrous morphology worsened with increasing drug content of the core or shell to some extent. The core/shell was amorphous nature, and changing drug content had little influence on the wetability of the core/shell fibers. The release accelerated with drug content increasing in the fibers, and RES and XAN showed gradient release, which the release rate of RES was slower than XAN. These two drugs could sustain release for 350 h. When the blend ratios of RES/PEO and XAN/PLGA were 50/50 and 10/90 in the fibers, the fiber mesh showed the best mechanical properties, of which the tensile strength and elongation at break were 2.85 ± 0.10 MPa and 55.23 ± 2.53%, respectively. The medicated fibers presented good characteristics of inhibiting breast cancer cell activity.

Preparation of alginate oligosaccharide nanoliposomes and an analysis of their inhibitory effects on Caco-2 cells.

The conditions were optimised for preparing Alginate oligosaccharide (AOS) nanoliposomes, and Caco-2 cell experiments were carried out to examine their antitumour effects. The optimal formulation of AOS nanoliposomes was as follows: a phosphatidylcholine-to-cholesterol ratio of 5.12, AOS concentration of 8.44 mg/mL, Tween 80 concentration of 1.11%, and organic phase to aqueous phase ratio of 5.25. Under the above conditions, the experimental encapsulation efficiency was 65.84%, and the AOS nanoliposomes exhibited a small particle size of 323 nm. After Caco-2 cells were treated with AOS liposomes and AOS for 24 h, AOS nanoliposomes inhibited the growth of Caco-2 cells to a greater extent than AOS at concentrations of 0.0625, 0.125, 0.25, 0.5 and 1 mg/mL (P < 0.01). LDH leakage exhibited a concentration-dependent increase following treatment with 0.5-1 mg/mL AOS nanoliposomes, and the inhibitory effect of AOS nanoliposomes exhibited a more significant difference than AOS (P < 0.01). Cells treated with 0.5 mg/mL and 1 mg/mL AOS nanoliposomes displayed a substantial and significant increase in activity compared with AOS (P < 0.01). Based on these results, AOS nanoliposomes exerted a more significant effect on inhibiting Caco-2 cell proliferation than AOS.

Protective effects of dehydrocostuslactone on rat hippocampal slice injury induced by oxygen­glucose deprivation/reoxygenation.

The present study aimed to investigate the protective effects of dehydrocostuslactone (DHL) against rat hippocampal slice injury caused by oxygen­glucose deprivation/reoxygenation (OGD/R). Rat hippocampal slice injury was induced by OGD/R in vitro, and the degree of injury was evaluated through a lactate dehydrogenase (LDH) assay and 2,3,5­triphenyltetrazolium chloride (TTC) staining. The protein expression levels of B­cell lymphoma-2 (Bcl­2), Bcl­2­associated X protein (Bax), cytochrome c (cyt­c), apoptotic protease activating factor 1 (apaf­1), caspase­9, caspase­7, caspase­3, sequestosome 1 (SQSTM1) and microtubule­associated protein 1 light chain 3 (LC3) were analyzed through western blot analysis. The results showed that 1, 5 and 10 µM DHL decreased the levels of LDH (P<0.05) and increased the A490 value of TTC (P<0.05). Furthermore, the expression of Bcl­2 was enhanced, and the protein expression levels of Bax, cyt­c, apaf­1, caspase­9, caspase­7, caspase­3, SQSTM1 and LC3 were significantly inhibited (P<0.05), compared with those in the OGD/R group. These results suggested that DHL elicited protective effects against hippocampal OGD/R injury, and its underlying mechanism may be associated with inhibiting apoptosis.

Syringin prevents bone loss in ovariectomized mice via TRAF6 mediated inhibition of NF-κB and stimulation of PI3K/AKT.

BACKGROUND: Syringin, also called eleutheroside B, is a main bioactive phenolic glycoside in Acanthopanax senticosus (Rupr. et Maxim.) Harms. Based on the "kidney dominates bone" theory of TCM, A. senticosus can strengthen bone and Syringin may be one of the responsibilities. PURPOSE: The objectives of this study were to estimate the osteoporotic activity of Syringin and reveal the possible molecular mechanisms in vivo. METHODS: Sixty female ICR mice were randomly assigned into sham operated group (SHAM, treated with vehicle) and five ovariectomized subgroups (n = 10 each), treated with vehicle as OVX group, estradiol valerate (EV, 1 mg/kg/day) as positive group, and Syringin (10, 20 and 40 mg/kg/day) as low, moderate and high dosage groups. The therapeutic effect of Syringin against osteoporosis was systematically analyzed by determining the bone mineral density (BMD), bone biomechanical properties, bone microarchitecture and serum biochemical parameters, and the molecular mechanism was also evaluated. RESULTS: After three months of orally administrated intervention, Syringin (10, 20 and 40 mg/kg/day) significantly improved the BMD, bone maximum load and trabecular bone microarchitecture in ovariectomized mice, evidenced by the increased bone mineral content, tissue mineral content, tissue mineral density, trabecular thickness and trabecular number, as well as the decreased trabecular separation in OVX mice. Meanwhile, the activities of tartrate-resistant acid phosphatase, deoxypyridinoline and cathepsin K in OVX mice were also inhibited by Syringin, while the increased body weight and decreased uterus weight seemed not influenced by Syringin administration. Concerning the underlying molecular mechanisms, Syringin significantly downregulated the expression of tumor-necrosis factor receptor-associated factor 6 (TRAF6), nuclear factor kappa B (NF-κB) and receptor activator of nuclear factor kappa B ligand (RANKL) proteins levels, upregulated the expression of osteoprotegerin (OPG), phosphoinositide 3-kinase (PI3K) and protein kinase B (AKT) levels, suggesting that Syringin prevented bone lost by TRAF6-mediated inhibition of NF-κB and stimulation of PI3K/AKT, and subsequently increasing the OPG/RANKL ratio and inhibiting the osteoclastogenesis, finally promoting bone formation. CONCLUSIONS: All of the data implied Syringin possessed the potent anti-osteoporosis activity on ovariectomized mice, and the underlying molecular mechanism may be related to the NF-κB and PI3K/AKT signaling pathways.

Therapeutic Effect of Cistanoside A on Bone Metabolism of Ovariectomized Mice.

Cistanoside A (Cis A), an active phenylethanoid glycoside isolated from Cistanche deserticola Y. C. Ma, has received our attention because of its possible role in the treatment of osteoporosis. In the present study, we evaluated the effects of Cis A on an ovariectomized (OVX) mice model and investigated its underlying molecular mechanisms of action. After 12 weeks of orally-administrated intervention, Cis A (20, 40 and 80 mg/kg body weight/day) exhibited significant antiosteoporotic effects on OVX mice, evidenced by enhanced bone strength, bone mineral density and improved trabecular bone microarchitecture. Meanwhile, the activities of bone resorption markers, including tartrate-resistant acid phosphatase (TRAP), deoxypyridinoline (DPD) and cathepsin K, were decreased, and the bioactivity of bone formation marker alkaline phosphatase (ALP) was increased. Mechanistically, Cis A inhibited the expression of TNF-receptor associated factor 6 (TRAF6), an upstream molecule that is shared by both nuclear factor kappa-light chain enhancer of activated B cells (NF-κB) and phosphatidylinositol 3-kinase (PI3K)/Akt pathways and subsequently suppressed the levels of receptor activators of nuclear factor kappaB ligand (RANKL), downregulated the expression of NF-κB and upregulated osteoprotegerin (OPG), PI3K and Akt, which means Cis A possessed antiosteoporotic activity in ovariectomized mice via TRAF6-mediated NF-kappaB inactivation and PI3K/Akt activation. Put together, we present novel findings that Cis A, by downregulating TRAF6, coordinates the inhibition of NF-κB and stimulation of PI3K/Akt pathways to promote bone formation and prevent bone resorption. These data demonstrated the potential of Cis A as a promising agent for the treatment of osteoporosis disease.

[Identification of Volatile Chemical Constituents from Hui Formula "Ha Hei Lili" by GC-MS].

OBJECTIVE: The volatile components of the Hui formula "Ha Hei Lili" were extracted by steam distillation extraction (SD) and supercritical CO2 fluid extraction, and the structures were analyzed and identified by GC-MS. METHODS: The GC-MS conditions were set as follows: Rxi-5Sil MS quartz capillary column (30 m x 0.25 mm, 0.25 µm), the initial temperature of 50 degrees C to keep 1 min, to 10 degrees C/min heating to 120 degrees C, maintained 3 min, then to 3 degrees C/min heating to 200 degrees C, maintained 3 min, and then to 5 degreesC/min heating to 290 degrees C, maintained until completion of analysis; helium as the carrier gas, column flow rate 1.0 ml/min, split ratio 25: 1, inlet temperature 250 degrees C, EI ionization source 70 eV, ion source temperature 230 degrees C, scan range of m/z 35 - 500. RESULTS: Yield of volatile oil were 0.21% and 5.44% extracted by SD and SFE methods, respectively; and for SD method, 36 kinds of compounds were identified, accounted for 87.02% of total mass of volatile oil; for SFE method, 38 kinds of constituents were identified, accounted for 97.47% of total mass of volatile oil. CONCLUSION: The type of constituents contained in the volatile oil extracted by SD and SFE methods are totally different; and GC-MS can be used to identify the structures and relative content of volatile components, the results of this study can provide an experimental basis for development and utilization of Hui formula "Ha Hei Lili".