Allosteric SHP2 inhibition enhances regorafenib's effectiveness in colorectal cancer treatment.

Colorectal cancer (CRC) is the third most common cancer globally. Regorafenib, a multi-target kinase inhibitor, has been approved for treating metastatic colorectal cancer patients who have undergone at least two prior standard anti-cancer therapies. However, regorafenib efficacy as a single agent remains suboptimal. A promising target at the crossroads of multiple signaling pathways is the Src homology 2 domain-containing protein tyrosine phosphatase (SHP2). However, a combination approach using SHP2 inhibitors (SHP099) and anti-angiogenic drugs (Regorafenib) has not been reported in current research. In this study, we conducted in vitro experiments combining SHP099 and regorafenib and established an MC-38 colon cancer allograft mouse model. Our results revealed that co-treatment with SHP099 and regorafenib significantly inhibited cell viability and altered the biological characteristics of tumor cells compared with treatment alone in vitro. Furthermore, the combination strategy demonstrated superior therapeutic efficacy compared to monotherapy with either drug. This was evidenced by reduced tumor size, decreased proliferation, increased apoptosis, normalized tumor microvasculature, and improved antitumor immune response in vivo. These findings suggest that the combination of an SHP2 inhibitor and regorafenib is a promising therapeutic approach for patients with colorectal cancer.

Long-term exposure to aryl hydrocarbon receptor agonist neburon induces reproductive toxicity in male zebrafish (Danio rerio).

Neburon is a phenylurea herbicide that is widely used worldwide, but its toxicity is poorly studied. In our previous study, we found that neburon has strong aryl hydrocarbon receptor (AhR) agonist activity, but whether it causes reproductive toxicity is not clear. In the present study, zebrafish were conducted as a model organism to evaluate whether environmental concentrations of neburon (0.1, 1 and 10 µg/L) induce reproductive disorder in males. After exposure to neburon for 150 days from embryo to adult, that the average spawning egg number in high concentration group was 106.40, which was significantly lower than 193.00 in control group. This result was mainly due to the abnormal male reproductive behavior caused by abnormal transcription of genes associated with reproductive behavior in the brain, such as secretogranin-2a. The proportions of spermatozoa in the medium and high concentration groups were 82.40% and 83.84%, respectively, which were significantly lower than 89.45% in control group. This result was mainly caused by hormonal disturbances and an increased proportion of apoptotic cells. The hormonal disruption was due to the significant changes in the transcription levels of key genes in the hypothalamus-pituitary-gonadal axis following neburon treatment. Neburon treatment also significantly activated the AhR signaling pathway, causing oxidative stress damage and eventually leading to a significant increase in apoptosis in the exposed group. Together, these data filled the currently more vacant profile of neburon toxicity and might provide information to assess the ecotoxicity of neburon on male reproduction at environmentally relevant concentrations.

New Hybrid Ethylenediurea (EDU) Derivatives and Their Phytoactivity.

Natural and synthetic phytohormones are widely used in agriculture. The synthetic cytokinin ethylenediurea (EDU) induces protection in plants against ozone phytotoxicity. In our study, new hybrid derivatives of EDU were synthesized and tested for phytoactivity. The germination potential (Gp), germination of seeds (G), and relative water content in leaves (RWC), characterizing the drought resistance of plants, were determined. The results of laboratory studies showed that EDU and its hybrid derivatives have a positive effect on root length, the growth and development of shoots, as well as the ability of plants to tolerate stress caused by a lack of water.

Assessing Patient Risk, Benefit, and Outcomes in Drug Development: A Decade of Lenvatinib Clinical Trials: A Systematic Review.

IMPORTANCE: Chemotherapy agents are typically initially tested in their most promising indications; however, following initial US FDA approval, new clinical trials are often initiated in less promising indications where patients experience a worse burden-benefit ratio. The current literature on the burden-benefit profile of lenvatinib in non-FDA-approved indications is lacking. OBJECTIVE: This study aimed to evaluate published clinical trials of lenvatinib in order to determine the burden-benefit profile for patients over time. EVIDENCE REVIEW: On 25 May 2023, we searched the Pubmed/MEDLINE, Embase, Cochrane CENTRAL, and ClinicalTrials.gov databases for clinical trials of lenvatinib used to treat solid cancers. Eligible articles were clinical trials, containing adult participants, published in English, and involving solid tumors. Screening and data collection took place in a masked, duplicate fashion. For each eligible study, we collected adverse event data, trial characteristics, progression-free survival (PFS), overall survival (OS), and objective response rate (ORR). Trials were classified as positive when meeting their primary endpoint and safety, negative (not meeting either criteria), or indeterminate (lacking prespecified primary endpoint). FINDINGS: Expansion of clinical trial testing beyond lenvatinib's initial FDA indication demonstrated a consistent rise in cumulative adverse events, along with a decline in drug efficacy. Lenvatinib was tested in 16 cancer indications, receiving FDA approval in 4. A total of 5390 Grade 3-5 adverse events were experienced across 6225 clinical trial participants. Expanded indication testing further demonstrated widely variable ORR (11-69%), OS (6.2-32 months), and PFS (3.6-15.7 months) across all indications. After initial FDA approval, clinical trial results in expanded indications were less likely to meet their primary endpoints, particularly among non-randomized clinical trials. CONCLUSION AND RELEVANCE: Our paper evaluated the effectiveness of lenvatinib for its FDA-approved indications; however, expansion of clinical trials into novel indications was characterized by diminished efficacy, while patients experienced a high burden of adverse events consistent with lenvatinib's established safety profile. Furthermore, clinical trials testing in novel indications was marked by repeated phase I and II clinical trials along with a failure to progress to phase III clinical trials. Future clinical trials using lenvatinib as an intervention should carefully evaluate the potential benefits and burden patients may experience.

CXCL1-CXCR2 axis mediates inflammatory response after sciatic nerve injury by regulating macrophage infiltration.

Macrophages play a crucial role in the inflammatory response following sciatic nerve injury. Studies have demonstrated that C-X-C motif chemokine (CXCL) 1 recruit macrophages by binding to C-X-C chemokine receptor (CXCR) 2 and participates in the inflammatory response of various diseases. Based on these findings, we aimed to explore the role of the CXCL1-CXCR2 axis in the repair process after peripheral nerve injury. Initially, we simulated sciatic nerve injury and observed an increased expression of CXCL1 and CXCR2 in the nerves of the injury group. Both in vivo and in vitro experiments confirmed that the heightened CXCL1 expression occurs in Schwann cells and is secreted, while the elevated CXCR2 is expressed by recruited macrophages. In addition, in vitro experiments demonstrated that the binding of CXCL1 to CXCR2 can activate the NLRP3 inflammasome and promote the production of interleukin-1 beta (IL-1ß) in macrophages. However, after mice were subjected to sciatic nerve injury, the number of macrophages and the expression of inflammatory factors in the sciatic nerve were reduced following treatment with the CXCR2 inhibitor SB225002. Simultaneously, we evaluated the sciatic nerve function index, the expression of p75 neurotrophic factor receptor (p75NTR), and myelin proteins, and all of these results were improved with the use of SB225002. Thus, our results suggest that after sciatic nerve injury, the CXCL1-CXCR2 axis mediates the inflammatory response by promoting the recruitment and activation of macrophages, which is detrimental to the repair of the injured nerves. In contrast, treatment with SB225002 promotes the repair of injured sciatic nerves.

Synthesis of Sorafenib-Ruthenium Complexes, Investigation of Biological Activities and Applications in Drug Delivery Systems as an Anticancer Agent.

Sorafenib, a multiple kinase inhibitor, is widely used as a first-line treatment for hepatocellular carcinoma. However, there is a need for more effective alternatives when sorafenib proves insufficient. In this study, we aimed to design a structure that surpasses sorafenib's efficacy, leading us to synthesize sorafenib-ruthenium complexes for the first time and investigate their properties. Our results indicate that the sorafenib-ruthenium complexes exhibit superior epidermal growth factor receptor (EGFR) inhibition compared to sorafenib alone. Interestingly, among these complexes, Ru3S demonstrated high activity against various cancer cell lines including sorafenib-resistant HepG2 cells while exhibiting significantly lower cytotoxicity than sorafenib in healthy cell lines. Further evaluation of cell cycle, cell apoptosis, and antiangiogenic effects, molecular docking, and molecular dynamics studies revealed that Ru3S holds great potential as a drug candidate. Additionally, when free Ru3S was encapsulated into polymeric micelles M1, enhanced cytotoxicity on HepG2 cells was observed. Collectively, these findings position Ru3S as a promising candidate for EGFR inhibition and warrant further exploration for drug development purposes.

Inhibition of RhoGEF/RhoA alleviates regorafenib resistance and cancer stemness via Hippo signaling pathway in hepatocellular carcinoma.

Patients with hepatocellular carcinoma (HCC) are vulnerable to drug resistance. Although drug resistance has been taken much attention to HCC therapy, little is known of regorafenib and regorafenib resistance (RR). This study aimed to determine the drug resistance pattern and the role of RhoA in RR. Two regorafenib-resistant cell lines were constructed based on Huh7 and Hep3B cell lines. In vitro and in vivo assays were conducted to study RhoA expression, the activity of Hippo signaling pathway and cancer stem cell (CSC) traits. The data showed that RhoA was highly expressed, Hippo signaling was hypoactivated and CSC traits were more prominent in RR cells. Inhibiting RhoA could reverse RR, and the alliance of RhoA inhibition and regorafenib synergistically attenuated CSC phenotype. Furthermore, inhibiting LARG/RhoA increased Kibra/NF2 complex formation, prevented YAP from shuttling into the nucleus and repressed CD44 mRNA expression. Clinically, the high expression of RhoA correlated with poor prognosis. LARG, RhoA, YAP1 and CD44 show positive correlation with each other. Thus, inhibition of RhoGEF/RhoA has the potential to reverse RR and repress CSC phenotype in HCC.

5-Methoxytryptophan enhances the sensitivity of sorafenib on the inhibition of proliferation and metastasis for lung cancer cells.

BACKGROUND: Lung cancer is a leading cause of cancer-related mortality worldwide, and effective therapies are limited. Lung cancer is a leading cause of cancer-related mortality worldwide with limited effective therapy. Sorafenib is a multi-tyrosine kinase inhibitor frequently used to treat numerous types of malignant tumors. However, it has been demonstrated that sorafenib showed moderate antitumor activity and is associated with several side effects in lung cancer, which restricted its clinical application. This study aimed to examine the antitumor effect of the combination treatment of sorafenib and 5-methoxytryptophan (5-MTP) on cell growth and metastasis of Lewis lung carcinoma (LLC) cells. METHOD: The anticancer effect of the combination treatment of sorafenib and 5-MTP was determined through cytotoxicity assay and colony forming assays. The mechanism was elucidated using flow cytometry and western blotting. Wound healing and Transwell assays were conducted to evaluate the impact of the combination treatment on migration and invasion abilities. An in vivo model was employed to analyze the effect of the combination treatment on the tumorigenic ability of LLC cells. RESULT: Our results demonstrated that the sorafenib and 5-MTP combination synergistically reduced viability and proliferation compared to sorafenib or 5-MTP treatment alone. Reduction of cyclin D1 expression was observed in the sorafenib alone or combination treatments, leading to cell cycle arrest. Furthermore, the sorafenib-5-MTP combination significantly increased the inhibitory effect on migration and invasion of LLC cells compared to the single treatments. The combination also significantly downregulated vimentin and MMP9 levels, contributing to the inhibition of metastasis. The reduction of phosphorylated Akt and STAT3 expression may further contribute to the inhibitory effect on proliferation and metastasis. In vivo, the sorafenib-5-MTP combination further reduced tumor growth and metastasis compared to the treatment of sorafenib alone. CONCLUSIONS: In conclusion, our data indicate that 5-MTP sensitizes the antitumor activity of sorafenib in LLC cells in vitro and in vivo, suggesting that sorafenib-5-MTP has the potential to serve as a therapeutic option for patients with lung cancer.

Soluble epoxide hydrolase inhibitor (TPPU) alleviates ferroptosis by regulating CCL5 after intracerebral hemorrhage in mice.

Soluble epoxide hydrolase (sEH) inhibition has been shown multiple beneficial effects against brain injuries of Intracerebral hemorrhage (ICH). However, the underlying mechanism of its neuroprotective effects after ICH has not been explained fully. Ferroptosis, a new form of iron-dependent programmed cell death, has been shown to be implicated in the secondary injuries after ICH. In this study, We examined whether sEH inhibition can alleviate brain injuries of ICH through inhibiting ferroptosis. Expression of several markers for ferroptosis was observed in the peri-hematomal brain tissues in mice after ICH. lip-1, a ferroptosis inhibitor, alleviated iron accumulation, lipid peroxidation and the secondary damages post-ICH in mice model. Intraperitoneal injection of 1-Trifluoromethoxyphenyl-3- (1-propionylpiperidin-4-yl)urea (TPPU), a highly selective sEH inhibitor, could inhibit ferroptosis and alleviate brain damages in ICH mice. Furthermore, RNA-sequencing was applied to explore the potential regulatory mechanism underlying the effects of TPPU in ferroptosis after ICH. C-C chemokine ligand 5 (CCL5) may be the key factor by which TPPU regulated ferroptosis after ICH since CCL5 antagonist could mimic the effects of TPPU and CCL5 reversed the inhibitive effect of TPPU on ferroptosis and the neuroprotective effects of TPPU on secondary damage after ICH. Taken together, these data indicate that ferroptosis is a key pathological feature of ICH and Soluble epoxide hydrolase inhibitor can exert neuroprotective effect by preventing ferroptosis after ICH.

Regorafenib: A comprehensive drug profile.

Regorafenib is a small molecule tyrosine kinase inhibitor administered orally drug, act by inhibiting the activity of the VEGF receptors. It is used for the treatment of patients with metastatic colorectal cancer (CRC), advanced gastrointestinal stromal tumors, and hepatocellular carcinoma. This comprehensive profile on regorafenib includes an original data as well as data collected from the literature on Profiles of Methods of Drug Synthesis, different Physical Drug Profiles, Drug Analytical methods and Pharmacological profile (ADME). This chapter is divided into five main sections: General Description of the drug, Physical Characteristics, Methods of Preparation, Methods of Analysis, Pharmacology and List of References. These main sections are further divided to many sub-titles to cover most aspect of the drug in the light of the available literature. Among these sub-titles are the formulae, Elemental Analysis, physical characteristics which include constant of ionization, solubility, X-ray powder diffraction pattern, TGA, thermal conduct and spectroscopic and stability. Additionally, analytical techniques including Electrochemical, Spectrophotometric and chromatographic methods, ADME profiles and pharmacological effects were also discussed. Furthermore, methods and schemes are outlined for the preparation of the drug substance.

RARRES1 inhibits hepatocellular carcinoma progression and increases its sensitivity to lenvatinib through interaction with SPINK2.

BACKGROUND: Lenvatinib is an oral small molecule inhibitor approved for treating patients with unresectable hepatocellular carcinoma (HCC) worldwide. Increasing cell sensitivity to lenvatinib would be an effective method of improving therapeutic efficacy. METHODS: High throughput methods was used to scan the differentially expressed genes (DEGs) related to lenvatinib sensitivity in HCC cells. Gain- and loss-function experiments were used to explore the functions of these DEGs in HCC and lenvatinib sensitivity. CO-IP assay and rescue experiments were utilized to investigate the mechanism. RESULTS: We identified that RAR responder protein 1 (RARRES1), a podocyte-specific growth arrest gene, was among significantly upregulated DEGs in HCC cells following lenvatinib treatment. Functional analysis showed that ectopic RARRES1 expression decreased HCC progression in vitro and in vivo, as well as improving tumor sensitivity to lenvatinib, while RARRES1 silencing increased HCC cell proliferation and migration. Mechanistically, co-immunoprecipitation assays demonstrated that RARRES1 interacted with serine protease inhibitor Kazal-type 2 (SPINK2) in HCC cells. Further, SPINK2 overexpression suppressed HCC cell proliferation and migration, as well as increasing sensitivity to lenvatinib whereas SPINK2 knockdown promoted cell progression and decreased lenvatinib sensitivity. The mRNA and protein levels of RARRES1 and SPINK2 were low in HCC tissue samples, relative to those in normal liver tissue. CONCLUSIONS: Our findings highlighted that RARRES1 can inhibit HCC progression and regulate HCC sensitivity to lenvatinib by interacting SPINK2, representing a new tumor suppressor RARRES1/SPINK2 axis in HCC that modulates sensitivity to lenvatinib.

Cross-Species Comparison of the Pan-RAF Inhibitor LY3009120's Anti-Tumor Effects in Equine, Canine, and Human Malignant Melanoma Cell Lines.

Malignant melanomas (MMs) are the abnormal proliferation of melanocytes and are one of the lethal skin cancers in humans, equines, and canines. Accordingly, MMs in companion animals can serve as naturally occurring animal models, completing conventional cancer models. The common constitutive activation of the MAPK and PI3K pathways in MMs has been described in all three species. Targeting the related pathways is considered a potential option in comparative oncologic approaches. Herein, we present a cross-species comparative analysis exposing a set of ten melanoma cell lines (one human, three equine, and six canine) derived from primary tumors or metastasis to a pan-RAF and RAF dimer inhibitor (LY3009120). Cellular response (proliferation, biomass, metabolism, early and late apoptosis/necrosis, and morphology) and the presence of pathogenic single-nucleotide variants (SNVs) within the mutational hotspot genes BRAF exon 11 and 15, NRAS exon 2 and 3, KRAS exon 2, and KIT exon 11 were analyzed. This study showed that equine malignant melanoma (EMM) cells (MelDuWi) harbor the KRAS p.Q61H mutation, while canine malignant melanoma (CMM) cells (cRGO1 and cRGO1.2) carry NRAS p.G13R. Except for EMM metastasis cells eRGO6 (wild type of the above-mentioned hotspot genes), all melanoma cell lines exhibited a decrease in dose dependence after 48 and 72 h of exposure to LY3009120, independent of the mutation hotspot landscape. Furthermore, LY3009120 caused significant early apoptosis and late apoptosis/necrosis in all melanoma cell lines except for eRGO6. The anti-tumor effects of LY3009120 were observed in nine melanoma cell lines, indicating the potential feasibility of experimental trials with LY3009120. The present study reveals that the irradiation-resistant canine metastasis cells (cRGO1.2) harboring the NRAS p.G13R mutation are significantly LY3009120-sensitive, while the equine metastases-derived eRGO6 cells show significant resistance to LY3009120, which make them both valuable tools for studying resistance mechanisms in comparative oncology.

The Flt3-inhibitor quizartinib augments apoptosis and promotes maladaptive remodeling after myocardial infarction in mice.

BACKGROUND: Tyrosine kinase inhibitors (TKIs) targeting fms-like tyrosine kinase 3 (Flt3) such as quizartinib were specifically designed for acute myeloid leukemia treatment, but also multi-targeting TKIs applied to solid tumor patients inhibit Flt3. Flt3 is expressed in the heart and its activation is cytoprotective in myocardial infarction (MI) in mice. OBJECTIVES: We sought to test whether Flt3-targeting TKI treatment aggravates cardiac injury after MI. METHODS AND RESULTS: Compared to vehicle, quizartinib (10 mg/kg/day, gavage) did not alter cardiac dimensions or function in healthy mice after four weeks of therapy. Pretreated mice were randomly assigned to MI or sham surgery while receiving quizartinib or vehicle for one more week. Quizartinib did not aggravate the decline in ejection fraction, but significantly enhanced ventricular dilatation one week after infarction. In addition, apoptotic cell death was significantly increased in the myocardium of quizartinib-treated compared to vehicle-treated mice. In vitro, quizartinib dose-dependently decreased cell viability in neonatal rat ventricular myocytes and in H9c2 cells, and increased apoptosis as assessed in the latter. Together with H2O2, quizartinib potentiated the phosphorylation of the pro-apoptotic mitogen activated protein kinase p38 and augmented H2O2-induced cell death and apoptosis beyond additive degree. Pretreatment with a p38 inhibitor abolished apoptosis under quizartinib and H2O2. CONCLUSION: Quizartinib potentiates apoptosis and promotes maladaptive remodeling after MI in mice at least in part via a p38-dependent mechanism. These findings are consistent with the multi-hit hypothesis of cardiotoxicity and make cardiac monitoring in patients with ischemic heart disease under Flt3- or multi-targeting TKIs advisable.

Astaxanthin Augmented the Anti-Hepatocellular Carcinoma Efficacy of Sorafenib Through the Inhibition of the JAK2/STAT3 Signaling Pathway and Mitigation of Hypoxia within the Tumor Microenvironment.

SCOPE: The optimization of anti-cancer drug effectiveness through dietary modifications has garnered significant attention among researchers in recent times. Astaxanthin (AST) has been identified as a safe and biologically active dietary supplement. METHODS AND RESULTS: The tumor-bearing mice are treated with sorafenib, along with supplementation of 60 mg kg-1 AST during the treatment. The coadministration of AST and a subclinical dosage of 10 mg kg-1 sorafenib demonstrates a tumor inhibition rate of 76.5%, which is notably superior to the 45% inhibition rate observed with the clinical dosage of 30 mg kg-1 sorafenib (p < 0.05). The administration of AST leads to a tumor inhibition increase of around 25% when combined with the clinical dose of 30 mg kg-1 sorafenib (p <0.05). AST enhances the inhibitory effect of sorafenib on tumor angiogenesis through the JAK2/STAT3 signaling pathway. Furthermore, AST exhibits a reduction in hypoxia within the tumor microenvironment. CONCLUSION: The results suggest that AST supplement enhances the inhibitory effects of sorafenib on hepatocellular carcinoma. This study presents a new dietary management program for oncology patients.

Effect of forchlorfenuron and thidiazuron on kiwifruits' internal qualities, optical properties and their relationship during growth.

Forchlorfenuron (1-(2-chloropyridin-4-yl)-3-phenylurea, CPPU) and thidiazuron (N-Phenyl-N'-1,2,3-thiadiazol-5-ylurea, TDZ) are two widely used plant growth regulators in kiwifruit cultivation. They can promote fruit size, but it is unclear whether they have same effect on internal qualities, optical properties and cell structure of kiwifruit, and whether the kiwifruits treated with CPPU and TDZ can be identified based on optical properties. To answer these questions, the kiwifruits treated with 20 mg/L CPPU and 2 mg/L TDZ solutions were used as samples, and the untreated kiwifruits were used as control to investigate the optical properties (absorption coefficient µa and reduced scattering coefficient µs'), internal qualities (soluble solids content (SSC), firmness and moisture content) and microstructure of pulp tissue during the growth. Moreover, the relationship between the optical properties and internal qualities were analyzed, and the potential for identifying the kiwifruits treated with CPPU and TDZ based on optical properties was evaluated. The results showed that CPPU and TDZ increased the SSC and reduced the firmness of kiwifruits, but had some different effects on the moisture content and cell size. CPPU and TDZ did not influence the change trend of µa and µs' with wavelength, but affected their values and the relationship with internal qualities. In general, the mean µa of the kiwifruits treated with CPPU and with TDZ was the largest and the smallest at the absorption peaks (980 nm, 1190 nm and 1420 nm), respectively. The linear discriminant analysis modeling results showed that the spectra of µa with µs' had greater potential in identifying the kiwifruits treated with CPPU/TDZ with accuracy of 75.76 %.

SKI-349, a Sphingosine Kinases 1/2 Inhibitor, Suppresses Cell Viability, Invasion, and AKT/mTOR Signaling Pathway, and Shows Synergistic Cytotoxic Effects with Sorafenib in Hepatocellular Carcinoma.

SKI-349 is a novel sphingosine kinases (SPHK) inhibitor with anti-tumor effects. This study aimed to assess the effect of SKI-349 on cell biological behaviors, downstream pathways, and its synergistic effect with sorafenib in hepatocellular carcinoma (HCC). HCC cell lines (Huh7 and Hep3B) were treated with SKI-349 at concentrations of 1, 2, 4, or 8 µM. Then, SPHK1/2 activity, cell viability, proliferation, apoptosis, invasion, and protein expressions of phosphorylated-protein kinase B (p-AKT), AKT, phosphorylated-mammalian target of rapamycin (p-mTOR) and mTOR were detected. Combination index values of SKI-349 (0, 1, 2, 4, or 8 µM) and sorafenib (0, 2.5, 5, 10, or 20 µM) were calculated. SKI-349 decreased the relative SPHK1 and SPHK2 activity compared with blank control in a dose-dependent manner in the Huh7 and Hep3B cell lines. Meanwhile, SKI-349 reduced cell viability, 5-ethynyl-2'-deoxyuridine (EdU) positive cells, and invasive cells, while it increased apoptotic cells compared to blank control in a dose-dependent manner in Huh7 and Hep3B cell lines. Based on the western blot assay, SKI-349 decreased the ratio of p-AKT to AKT and that of p-mTOR to mTOR compared with blank control in a dose-dependent manner in the Huh7 and Hep3B cell lines. Additionally, SKI-349 combined with sorafenib declined cell viability with concentration gradient effects compared to SKI-349 sole treatment, and they had synergistic cytotoxic effects in Huh7 and Hep3B cell lines. SKI-349 suppresses SPHK1 and SPHK2 activity, cell viability, invasion, and AKT/mTOR signaling pathway, as well as exhibits a synergistic cytotoxic effect with sorafenib in HCC.

Regorafenib in advanced solitary fibrous tumour: Results from an exploratory phase II clinical study.

BACKGROUND: To investigate the activity of regorafenib in advanced solitary fibrous tumour (SFT). METHODS: An Italian monocentric investigator-initiated exploratory single-arm Phase II trial was conducted of regorafenib in adult patients with advanced and progressive SFT, until progression or limiting toxicity. Prior treatment with antiangiogenics was allowed. Primary and secondary end-points were: overall response rate (ORR) by Choi criteria, and ORR by RECIST, progression-free survival (PFS), overall survival (OS). RESULTS: From January 2016 to February 2021, 18 patients were enroled [malignant-SFT = 13; dedifferentiated-SFT (D-SFT) = 4; typical-SFT (T-SFT) = 1]. Fourteen patients were pre-treated, in 12 cases with antiangiogenics (median [m-] lines of treatment = 3). Sixteen patients were evaluable for response (one screening failure; one early discontinuation). Six/16 (35.2%) required a definitive dose reduction. ORR by Choi was 37.5% (95% CI: 15.2-64.6), with 6/16 (37.5%) partial responses (PR), 6/16 (37.5%) stable disease (SD) and 4/16 (25%) progressions; 5/6 responses occurred in patients pre-treated with antiangiogenics. No responses were detected in D-SFT. Best RECIST responses were: 1/16 (6.2%) PR, 12/16 (75%) SD, 3/16 (18.8%) progressions. At 48.4 month m-FU, m-PFS by Choi was 4.7 (inter-quartile range: 2.4-13.1) months, with 31.2% patients progression-free at 1 year. CONCLUSION: Regorafenib showed activity in SFT, with 30% patients free-from-progression at one year. Responses were observed also in patients pretreated and refractory to another antiangiogenic agents. However, ORR and m-PFS were lower than reported with other antiangiogenics, and this was possibly due to discrepancies in the patient population and the high-rate of dose reductions.

Therapeutic inhibition of ATR in differentiated thyroid cancer.

Ataxia telangiectasia and Rad3-related protein (ATR) is a critical component of the DNA damage response and a potential target in the treatment of cancers. An ATR inhibitor, BAY 1895344, was evaluated for its use in differentiated thyroid cancer (DTC) therapy. BAY 1895344 inhibited cell viability in four DTC cell lines (TPC1, K1, FTC-133, and FTC-238) in a dose-dependent manner. BAY 1895344 treatment arrested DTC cells in the G2/M phase, increased caspase-3 activity, and caused apoptosis. BAY 1895344 in combination with either sorafenib or lenvatinib showed mainly synergistic effects in four DTC cell lines. The combination of BAY 1895344 with dabrafenib plus trametinib revealed synergistic effects in K1 cells that harbor BRAFV600E. BAY 1895344 monotherapy retarded the growth of K1 and FTC-133 tumors in xenograft models. The combinations of BAY 1895344 plus lenvatinib and BAY 1895344 with dabrafenib plus trametinib were more effective than any single therapy in a K1 xenograft model. No appreciable toxicity appeared in animals treated with either a single therapy or a combination treatment. Our findings provide the rationale for the development of clinical trials of BAY 1895344 in the treatment of DTC.

Broad-spectrum kinome profiling identifies CDK6 upregulation as a driver of lenvatinib resistance in hepatocellular carcinoma.

Increasing evidence has demonstrated that drug resistance can be acquired in cancer cells by kinase rewiring, which is an obstacle for efficient cancer therapy. However, it is technically challenging to measure the expression of protein kinases on large scale due to their dynamic range in human proteome. We employ a lysine-targeted sulfonyl fluoride probe, named XO44, which binds to 133 endogenous kinases in intact lenvatinib-resistant hepatocellular carcinoma (HCC) cells. This analysis reveals cyclin-dependent kinase 6 (CDK6) upregulation, which is mediated by ERK/YAP1 signaling cascade. Functional analyses show that CDK6 is crucial in regulation of acquired lenvatinib resistance in HCC via augmentation of liver cancer stem cells with clinical significance. We identify a noncanonical pathway of CDK6 in which it binds and regulates the activity of GSK3ß, leading to activation of Wnt/ß-catenin signaling. Consistently, CDK6 inhibition by palbociclib or degradation by proteolysis targeting chimeras (PROTACs) is highly synergistic with lenvatinib in vitro. Interestingly, palbociclib not only exerts maximal growth suppressive effect with lenvatinib in lenvatinib-resistant HCC models but also reshapes the tumor immune microenvironment. Together, we unveil CDK6 as a druggable target in lenvatinib-resistant HCC and highlight the use of a chemical biology approach to understand nongenetic resistance mechanisms in cancer.