Association of toxicity of sorafenib and sunitinib for human keratinocytes with inhibition of signal transduction and activator of transcription 3 (STAT3)

Sunitinib promotes apoptosis via p38 MAPK activation and STAT3 downregulation in oral keratinocytes

OBJECTIVE

Sunitinib, a targeted cancer drug, inhibits tyrosine kinases receptors and is widely used as first-line treatment for metastatic renal cell carcinoma. Patients undergoing chemotherapy with sunitinib frequently have oral mucosal complications, such as oral stomatitis, though cytotoxic effects of the drug on oral keratinocytes remain unknown.

METHODS

The effects of sunitinib on immortalized oral keratinocytes, RT7 cells, in regard to cell injury and apoptosis, as well as apoptosis-mediated signaling pathways were investigated.

RESULTS

Sunitinib treatment caused a significant increase in lactate dehydrogenase (LDH) in RT7 cells and primary oral keratinocytes. Additionally, the drug induced apoptosis-related events, such as DNA fragmentation, decreased anti-apoptotic Bcl-2 protein expression, and induction of cleaved PARP and caspase 3/9 in RT7 cells. Furthermore, phosphorylation of p38 MAPK, but not of ERK or JNK, was increased. On the contrary, constitutive phosphorylated STAT3 was decreased by sunitinib treatment, which was recovered by exposure to SB203580, a p38 MAPK inhibitor. Finally, SB203580 was found to reduce sunitinib-induced cell injury and apoptosis.

CONCLUSION

The present results indicate that sunitinib promotes cell injury and apoptosis in oral keratinocytes via p38 activation and STAT3 downregulation. Sunitinib-mediated oral complications may be associated with cytotoxic effects of the drug on oral keratinocytes.

Safety profile of vascular endothelial growth factor receptor tyrosine-kinase inhibitors in pediatrics: a pharmacovigilance disproportionality analysis

Introduction: existing research on children consists primarily of phase I/II clinical trials for VEGFR-TKI. System reports of safety on the use of VEGFR-TKI in pediatrics are lacking. Aim: to investigate the safety profiles of VEGFR-TKI in pediatrics via the FDA Adverse Event Reporting System (FAERS). Method: data regarding VEGFR-TKIs were extracted from the FAERS between 2004Q1 to 2022Q3 and categorized by the Medical Dictionary for Regulatory Activities (MedDRA). Population characteristics were analyzed, and reporting odds ratio (ROR) was performed to identify risk signals associated with VEGFR-TKI. Results: 53,921 cases containing 561 children were identified in the database from 18 May 2005, to 30 September 2022. Among those in the system organ class, skin, subcutaneous tissue disorders, and blood and lymphatic system disorders in pediatrics contributed to over 140 cases. Palmar-plantar eythrodysesthesia syndrome (PPES) in VEGFR-TKI presented the most significant 340.9 (95% 229.2-507.0). And pneumothorax also gave a high reporting odds ratio of 48.9 (95% 34.7-68.9). For a specific drug, musculoskeletal pain gave a ROR of 78.5 (95% 24.4-252.6) in cabozantinib and oesophagitis in lenvatinib with a ROR of 95.2 (95% 29.5-306.9). Additionally, hypothyroidism presented a high signal, especially sunitinib, with a ROR of 107.8 (95% 37.6-308.7). Conclusion: the present study explored the safety profile of VEGFR-TKI in pediatrics using the FAERS database. Multiple skin and subcutaneous tissue disorders, as well as blood and lymphatic system disorders, were common VEGFR-TKI-related AEs in system organ class. No serious hepatobiliary AEs were detected. For the specific AEs, PPES and pneumothorax were VEGFR-TKI-related AEs that presented significantly higher signals than those in the general population.

Evaluation of Antineoplastic Delayed-Type Hypersensitivity Skin Reactions In Vitro

Delayed-type hypersensitivity (DTH) is caused by a broad number of drugs used in clinic, and antineoplastic drugs show an elevated proportion of DTH, which potentially affects the quality of life of patients. Despite the serious problem and the negative economic impact deriving from market withdrawal of such drugs and high hospitalization costs, nowadays, there are no standard validated methods in vitro or in vivo to evaluate the sensitizing potential of drugs in the preclinical phase. Enhanced predictions in preclinical safety evaluations are really important, and for that reason, the aim of our work is to adapt in vitro DPRA, ARE-Nrf2 luciferase KeratinoSens^TM, and hCLAT assays for the study of the sensitizing potential of antineoplastic agents grouped by mechanism of action. Our results reveal that the above tests are in vitro techniques able to predict the sensitizing potential of the tested antineoplastics. Moreover, this is the first time that the inhibition of the VEGFR1 pathway has been identified as a potential trigger of DTH.

CircEIF5 contributes to hyperproliferation and inflammation of keratinocytes in psoriasis via p-NFκB and p-STAT3 signalling pathway

Psoriasis is a chronic, immune-mediated skin disease accompanied by hyperproliferation and inflammation of keratinocytes. Circular RNAs (circRNAs) as new players regulating the development of psoriasis have been reported in recent years. However, its mechanism has not yet been fully revealed. In this study, we identified that hsa_circ_0033469 (circEIF5) was highly expressed in psoriasis tissues compared with the normal skin. We investigated the functional roles of circEIF5 in proliferation and inflammatory of HaCat cells under M5-stimulated inflammatory condition. By using a approach of knockdown and overexpression of circEIF5, we showed that circEIF5 could promote proliferation by facilitating the G1/S transition and increase secretion of chemokines in HaCat cells. These moderating effects of circEIF5 were associated with the activating of the NF-κB and STAT3 signalling pathways. Moreover, NF-κB and STAT3 inhibition abrogated circEIF5-induced promotion of cell proliferation and chemokine secretion. These results indicated that through NF-κB and STAT3 signalling pathways, circEIF5 regulated the proliferation and chemokine secretion of HaCat cells and contributed to the pathogenesis of psoriasis, which might become a potent target for psoriasis treatment.

Discrimination of hand-foot skin reaction caused by tyrosine kinase inhibitors based on direct keratinocyte toxicity and vascular endothelial growth factor receptor-2 inhibition

Tyrosine kinase inhibitors (TKIs) are molecular-targeted anticancer drugs. Their benefits are limited by dermal toxicities, including hand-foot skin reaction (HFSR), which is commonly found in skin areas subjected to friction. The present study aimed to explain the incidence of HFSR in patients treated with TKIs by focusing on keratinocyte toxicity and inhibition of vascular endothelial growth factor receptor (VEGFR), which plays an essential role in angiogenesis. Mice with gene knockout for the immunosuppressive cytokine interleukin-10 exhibited HFSR-like phenotypes, such as cytotoxicity in keratinocytes and increased number and size of blood vessels after repeated doses of regorafenib, sorafenib, and pazopanib, all of which cause high incidence of HFSR, in combination with tape-stripping mimicking skin damage at the friction site. Comprehensive examination of the direct cytotoxic effects of 21 TKIs on primary cultured human keratinocytes revealed that 18 of them reduced the cell viability dose-dependently. Importantly, the ratio of the trough concentration in patients (C_trough) to the LC₅₀ values of cell viability reduction was higher than unity for four HFSR-inducing TKIs, suggesting that these TKIs cause keratinocyte toxicity at clinically relevant concentrations. In addition, eight HFSR-inducing TKIs caused inhibition of VEGFR-2 kinase activity, which was validated by their ratios of C_trough to the obtained IC_50,VEGFR-2 of more than unity. All 12 TKIs with no reported incidence of HFSR exhibited less than unity values for both C_trough/LC_{50,keratinocytes} and C_trough/IC_50,VEGFR-2. These results suggested that a combination of keratinocyte toxicity and VEGFR-2 inhibition may explain the incidence of HFSR upon TKI usage in humans.

Nivolumab-induced hypophysitis followed by acute-onset type 1 diabetes with renal cell carcinoma: a case report

Background

Immune checkpoint inhibitors have recently become widely used for the management of advanced cancer patients. During the development of immune checkpoint inhibitors (ICPIs), it was quickly recognized that they are associated with autoimmune or autoinflammatory side effects. These toxicities are known as immune-related adverse events (irAEs): common endocrine irAEs include hypophysitis and thyroid dysfunction, and uncommon irAEs include type 1 diabetes mellitus (T1DM).

Case presentation

A 62-year-old Japanese man with metastatic renal cell carcinoma was treated with sunitinib followed by the 10th cycle of treatment with the ICPI nivolumab. He had already had thyroiditis and hypophysitis due to these anti-cancer drugs. On admission, he showed an extremely elevated plasma glucose level (601 mg/dl) and a low C-peptide level, and was diagnosed with acute T1DM. The patient was treated with intravenous fluid infusion and continuous insulin infusion. On the second day, he was switched to multiple daily injections of insulin therapy. Since these treatments, his blood glucose levels have been stable and he has been treated with an additional 10 ICPI treatments for renal cell carcinoma for over a year.

Conclusions

Treatment with ICPIs is expected to increase in the future. There may be cases in which their use for cancer treatment is inevitable despite the side effects. As long as treatment with ICPI continues, multiple side effects can be expected in some cases. It is important to carefully observe the side effects that occur during ICPI treatment and to provide appropriate treatment for each side effect.

Sunitinib decreases the expression of KRT6A and SERPINB1 in 3D human epidermal models

Hand-foot skin reaction (HFSR) is a common side effect caused by several tyrosine kinase inhibitors, including sunitinib. However, the nature of the cornifying factors related to the molecular biological mechanisms underlying HFSR remains poorly understood. We used human keratinocyte models to investigate the key cornifying factors for dermatological and biological abnormalities induced by sunitinib. On the basis of the results of microarray analysis using the three-dimensional (3D) human epidermal model, keratin (KRT)6A, serine protease inhibitor (SERPIN)B1, KRT5, and SERPIN Kazal-type 6 were selected as candidate genes related to HFSR. Sunitinib treatment significantly decreased the expression of SERPINB1 and KRT6A in the immunohistochemical staining of the 3D epidermal model. In PSVK1 cells, but not in normal human epidermal keratinocyte cells, both of which are human normal keratinocyte cell lines, sunitinib decreased the expression of KRT6A with a concomitant decrease in levels of phosphorylated extracellular signal-regulated kinases (ERK)1/2 and phosphorylated p38 mitogen-activated protein kinase (MAPK). Inhibitors of the ERK and p38 MAPK signal pathways also significantly decreased KRT6A expression. Sunitinib-induced decrease in KRT6A expression was suppressed by the inhibition of glycogen synthase kinase-3β by enhancing ERK1/2 and p38 MAPK phosphorylation. Thus, sunitinib reduces the expression of KRT6A and SERPINB1 by inhibiting the ERK1/2 and p38 MAPK signalling pathways in the skin model. These changes in expression contribute to the pathology of HFSR.

Potential toxic effects of 4-OH-chlorothalonil and photodegradation product on human skin health

Chlorothalonil (CHT) is widely used in agriculture as a fungicide and has been detected in various ecosystems along with its degradation products. A primary intermediate product of degradation, 4-hydroxychlorothalonil (4-OH-CHT) has demonstrated toxic effects on aquatic organisms. However, the toxic effects of 4-OH-CHT on human health and the impacts of environmental factors on the toxicity remain unclear. To understand the environmental modification on the toxicity of 4-OH-CHT to human health, we used a three-dimensional human skin culture model. 4-OH-CHT and irradiated 4-OH-CHT were applied to the model for the dermatoxicity analyses. Although neither the 4-OH-CHT nor the irradiated 4-OH-CHT inhibited the cell proliferation, the 4-OH-CHT significantly attenuated the keratinocyte migration by 26% at a concentration of 20 ppb and by 44 % at 100 ppb. The 4-OH-CHT also demonstrated inhibitory effects on keratinocyte differentiation at both 20 ppb and 100 ppb. In contrast, photodegraded 4-OH-CHT did not show inhibitory effects on the migration and differentiation of the keratinocytes at any concentration. Similarly, the 4-OH-CHT treated 3D keratinocyte culture dramatically activated the co-cultured dermal fibroblast cells by increasing the production of α smooth muscle actin (α-SMA) and pro-Collagen Iα. The mRNA levels of these two proteins were upregulated by 1.13 and 10.97 folds with the stimulation of 100 ppb 4-OH-CHT. The protein level of pro-Collagen Iα in dermal fibroblast cells was increased by 68 % with 100 ppb 4-OH-CHT. The photodegraded 4-OH-CHT failed to activate the co-cultured fibroblast cells. The 4-OH-CHT also enhanced pro-inflammatory cytokine production in keratinocytes compared to the photodegraded products. These results suggest that exposure to environmental 4-OH-CHT could increase the risk of inflammatory skin diseases in humans.

Anorexia, Hypertension, Pneumothorax, and Hypothyroidism: Potential Signs of Improved Clinical Outcome Following Apatinib in Advanced Osteosarcoma

Aim

Apatinib, a specific tyrosine kinase inhibitor (TKI) that targets mainly vascular endothelial growth factor receptor-2 (VEGFR-2) as well as Ret, c-Kit and c-Src, has been assessed in patients with advanced osteosarcoma (phase II), the primary report of which has been published in PMID 30559126. This sub-study explored the potential signs of Adverse Events (AEs) for apatinib-treated osteosarcoma.

Methods

Participants with advanced osteosarcoma progressing upon chemotherapy received apatinib until disease progression or unacceptable toxicity. Toxicities, progression-free survival (PFS), and clinical benefit rate (CBR) following treatment were evaluated.

Results

Of the 41 patients recruited to the study, 37 received treatment and constituted the safety population. At data cut-off (December 30, 2017), median follow-up for safety was 7.37 (IQR, 6.33–11.07) months. The most common grade 3–4 AEs were pneumothorax (16.22%), wound dehiscence (10.81%), proteinuria (8.11%), diarrhea (8.11%), and skin reaction (8.11%). Only hypertension was an independent predictive factor for both PFS (hazard ratio [HR], 0.44; P = 0.07) and CBR (P = 0.07). Anorexia was also significantly related to a longer PFS in a Cox regression model (HR, 0.35; P =0.01). For CBR, pneumothorax and hypothyroidism showed more clinical benefit (P = 0.07 and 0.00, respectively).

Conclusion

The results of this study suggest that anorexia, hypertension, pneumothorax, and hypothyroidism might be markers for a favorable clinical outcome following apatinib-treated refractory osteosarcoma.

Safety and Efficacy of Bis-Glyceryl Ascorbate (Amitose DGA) to Prevent Hand-Foot Skin Reaction in Patients With Renal Cell Carcinoma Receiving Sunitinib Therapy: Protocol for a Phase I/II, Uncontrolled, Single-Arm, Open-Label Trial

Background

Hand-foot skin reaction (HFSR) is a serious side effect induced by multiple-tyrosine kinase inhibitors (TKIs). HFSR can cause treatment interruption or decreased dosing. HFSR also markedly decreases quality of life and is associated with the therapeutic efficacy of multiple-TKIs. Therefore, the management and prevention of HFSR is an important issue; however, an effective method for its prevention has not been established. Specific ascorbic acid derivatives can reverse multiple-TKI-induced keratinocyte growth and pathological changes in vitro.

Objective

This study was designed to evaluate the safety of bis-glyceryl ascorbate (Amitose DGA), a novel, hydrosoluble, and moisturizing ascorbic acid derivative, in patients with renal cell carcinoma (RCC) receiving sunitinib therapy. This study was also designed to evaluate Amitose DGA’s preventive efficacy for sunitinib-induced HFSR.

Methods

This is a Phase I/II, single-center, uncontrolled, single-arm, open-label trial. We will recruit a total of 30 patients with RCC receiving sunitinib therapy, with a 2-week-on and 1-week-off schedule. The participants will apply Amitose DGA-containing cream over both palmar and plantar surfaces within two treatment cycles (ie, 6 weeks) of sunitinib in combination with a general moisturizing agent, in addition to standard-of-care processes. Safety assessments will include dermatological abnormalities, clinical laboratory tests, and incidence of adverse events. Efficacy assessments will include development of HFSR and therapeutic outcomes associated with sunitinib.

Results

Recruitment to the study began in August 2017 and is ongoing in Japan. To date, 21 subjects have been recruited. Study completion is expected in 2021.

Conclusions

This is the first clinical study of Amitose DGA-containing cream in patients with RCC who are receiving sunitinib therapy. The single-center, single-arm, open-label design was selected to maximize subject exposure and increase the likelihood of achieving our study endpoints. The results will provide valuable and preliminary evidence of the effects of Amitose DGA-containing cream on HFSR.

Trial Registration

UMIN Clinical Trials Registry UMIN000027209; https://upload.umin.ac.jp/cgi-open-bin/ctr /ctr_view.cgi?recptno=R000031174

International Registered Report Identifier (IRRID)

DERR1-10.2196/14636

Multikinase inhibitor sorafenib induces skin toxicities in tumor-bearing mice

OBJECTIVES

To investigate the pathologic changes and pathogenesis of multikinase inhibitor (MKI)-induced skin lesions in an animal model.

METHODS

Tumor-bearing nude mice and BDF1 mice were treated with different doses (30-240 mg/kg, Bid) of sorafenib. The pathology and severity of the skin lesions was assessed and evaluated. The concentration of sorafenib in the skin was also determined.

RESULTS

Sorafenib transiently induced skin rash at high doses (120-240 mg/kg). The induced skin lesions had pathological manifestations resembling the observations in human patients. The skin of mice treated with sorafenib had significantly increased pathological scores and thickness of the stratum spinosum compared with the control, and induced more severe cutaneous lesions in nude mice than in BDF1 mice. The severity of skin lesions was correlated with the local concentration of sorafenib in the skin, which was significantly higher in nude mice than in BDF1 mice. Sorafenib treatment significantly increased the expression of F4-80, Ly6G, tumor growth factor (TGF)-1β, Smad2/3, α-smooth-muscle actin, and proliferating cell nuclear antigen.

CONCLUSIONS

The severity of skin lesions was positively correlated with the concentration of sorafenib in the skin. Our results suggested the involvement of the TGF-β1/Smads signaling pathway in the skin reaction induced by MKIs.

Effects of VEGF and VEGFR polymorphisms on the outcome of patients with metastatic renal cell carcinoma treated with sunitinib: a systematic review and meta-analysis

To summarize and clarify the association between vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor (VEGFR) polymorphisms and the outcome in patients with metastatic renal cell carcinoma (mRCC) treated with sunitinib. A total of 8 studies including 900 patients were analyzed in this systematic review after screening the database of PubMed, EMBASE and Web of Science. Hazard ratios (HRs) with 95% confidence interval (CI) were used to evaluate the strength of the association. VEGFR1 rs9582036 AA/AC carriers and rs9554320 CC/AC carriers had more favorable overall survival (OS) in patients with mRCC treated with sunitinib (n = 3), but not in progression-free survival (PFS). In addition, VEGFA rs2010963 was associated with poorer PFS of mRCC (n = 1). VEGFA rs699947 was significant in predicting PFS by univariate analysis, but showed no statistical significance in OS (n = 1). VEGFR2 rs1870377 was verified to be associated with sunitinib OS (n = 1). Furthermore, patients with VEGFR3 rs307826 and rs307821 had shorter PFS and OS during sunitinib therapy (n = 2, respectively). Our results suggested that VEGF and VEGFR polymorphisms were associated with outcomes in sunitinib treated mRCC patients, especially VEGFR1 polymorphisms. However, considering the limited study numbers, its clinical application in sunitinib treated mRCC still needs further confirmation.

North African Medicinal Plants Traditionally Used in Cancer Therapy

Background: Cancer is a major cause of mortality worldwide with increasing numbers by the years. In North Africa, the number of cancer patients is alarming. Also shocking is that a huge number of cancer patients only have access to traditional medicines due to several factors, e.g., economic difficulties. In fact, medicinal plants are widely used for the treatment of several pathologies, including cancer. Truthfully, herbalists and botanists in North African countries prescribe several plants for cancer treatment. Despite the popularity and the potential of medicinal plants for the treatment of cancer, scientific evidence on their anticancer effects are still scarce for most of the described plants.

Objective: Bearing in mind the lack of comprehensive and systematic studies, the aim of this review is to give an overview of studies, namely ethnobotanical surveys and experimental evidence of anticancer effects regarding medicinal plants used in North Africa for cancer therapy.

Method: The research was conducted on several popular search engines including PubMed, Science Direct, Scopus and Web of Science. The research focused primarily on English written papers published between the years 2000 and 2016.

Results: This review on plants traditionally used by herbalists in North Africa highlights that Morocco and Algeria are the countries with most surveys on the use of medicinal plants in folk medicine. Among the plethora of plants used, Nigella sativa and Trigonella foenum-graecum are the most referred ones by herbalists for the treatment of cancer. Moreover, a plethora of scientific evidence qualifies them as candidates for further drug development. Furthermore, we report on the underlying cellular and molecular mechanisms.

Conclusion: Overall, this review highlights the therapeutic potential of some medicinal plants as anticancer agents. The North African flora offers a rich source of medicinal plants for a wide array of diseases, including cancer. The elucidation of their modes of action represents an indispensable condition for the rational development of new drugs for cancer treatment. Furthermore, testing the anticancer activity in vivo and in clinical trials are warranted to explore the full therapeutic potential of North African plants for cancer therapy.

Drug-induced pyoderma gangrenosum: a model to understand the pathogenesis of pyoderma gangrenosum

Pyoderma gangrenosum (PG) is a rare autoinflammatory condition in which the alteration of neutrophil function and the innate immune response play key roles in its pathogenesis. Cases of PG have been reported in patients being treated with certain medications, which may help us to understand some of the possible pathways involved in the aetiology of PG. The aim of this review is to review the cases of PG triggered by certain drugs and try to thoroughly understand the pathogenesis of the disease. To accomplish this, a PubMed search was completed using the following words: pyoderma gangrenosum, neutrophilic dermatosis, pathophysiology, drug-induced pyoderma gangrenosum. In total, we found 43 cases of drug-induced PG. Most of them were caused by colony-stimulating factors and small-molecule tyrosine kinase inhibitors. We propose that drugs induce PG through various mechanisms such as dysfunctional neutrophil migration and function, dysregulated inflammatory response, promotion of keratinocyte apoptosis and alteration of epigenetic mechanisms. PG is a rare condition with complex pathophysiology and drug-induced cases are even more scarce; this is the main limitation of this review. Understanding the possible mechanisms of drug-induced PG, via abnormal neutrophil migration and function, abnormal inflammation, keratinocyte apoptosis and alteration of epigenetic mechanisms would help to better understand the pathogenesis of PG and ultimately to optimize targeted therapy.

Prostaglandin E1 reduces the keratinocyte toxicity of sorafenib by maintaining signal transducer and activator of transcription 3 (STAT3) activity and enhancing the cAMP response element binding protein (CREB) activity

Hand-foot skin reaction (HFSR) is a common side effect of multiple tyrosine kinase inhibitors (mTKIs). HFSR can necessitate dose reductions or interruption of therapy owing to its negative effect on the quality of life. Therefore, effective use of mTKIs requires measures to prevent HFSR. We evaluated the effect of prostaglandin E₁ (PGE₁) on HFSR, because PGE₁ is already used to treat bed sores and skin ulcers and has established angiogenic and antiproliferative effects in keratinocytes. We found that the pathogenesis of sorafenib-induced HFSR is characterized by a decrease in levels of a phosphorylated signal transducer and activator of transcription 3 (STAT3). We investigated the effect of PGE₁ on the sorafenib-mediated reduction in phosphorylated STAT3 levels in HaCaT human epidermal keratinocytes. In cells treated with sorafenib, phosphorylated STAT3 levels decreased in a concentration-dependent manner, and this effect was blocked in cells treated with sorafenib and PGE₁. Furthermore, the expression of phosphorylated STAT3, the antiapoptotic proteins myeloid cell leukemia-1 (Mcl-1) and survivin decreased in cells pretreated with an inhibitor of cAMP response element binding protein (CREB). Cell viability increased in cells treated with sorafenib and PGE₁ compared with that in cells treated with sorafenib alone, and these effects were not observed in STAT3 knockdown HaCaT cells. Collectively, these findings indicate that PGE₁ blocks the inhibitory effects of sorafenib on cell growth by maintaining the activity of STAT3 and enhancing the CREB activity. Therefore, PGE₁ might represent an effective treatment for the prevention of sorafenib-induced HFSR.

Influence of VEGFR single nucleotide polymorphisms on the efficacy of sunitinib therapy against renal cell carcinoma

Single nucleotide polymorphisms (SNPs) of vascular endothelial growth factor receptor (VEGFR) may have effects on the MAPK/ERK/STAT3 signaling pathway, and the resulting phenotypes may influence the response to sunitinib-targeted therapy for renal cell carcinoma. In order to test this hypothesis patients with advanced renal cell carcinoma treated with sunitinib, were enrolled in our study. Peripheral blood samples were used to run a polymerase chain reaction-restriction fragment length polymorphism protocol to type candidate nucleotide polymorphism loci (VEGFR1, VEGFR2 and VEGFR3). The samples were also used in western blots to determine p-MAPK/ERK/STAT3 protein expression levels. The clinical responses to treatment were recorded and then a logistic regression method was applied to analyze the correlation between polymorphism of loci and effectiveness of sunitinib therapy. According to a follow-up visit (on average after 15 months of treatment) there were 16 complete responses (CR), 29 partial responses (PR) and 23 stable disease (SD) and progression of disease (PD) cases. Tests were carried out for 5 SNPs: VEGFR1 (rs664393), VEGFR2 (rsl870377 and rs7667298) and VEGFR3 (rs448012 and rs72816988). Mutation rates of rsl870377 and rs448012 loci in the CR+PR group were lower than those in the SD+PD group. No such differences were found for the other 3 loci. Relative expression levels of p-MAPk, p-ERK and p-STAT3 in the CR+PR group were significantly lower than those in the SD+PD group (P<0.05). The median progression-free survival and overall survival (OS) in the CR+PR group were higher than those in the SD+PD group (P<0.001). The median OS of the TT rsl870377 genotype was higher than that of the AA genotype, and the median OS of the GG rs448012 genotype was higher than that of the CC genotype (P<0.001). It was concluded through a logistic regression model that rsl870377 (AA) and rs448012 (GG) are independent risk factors closely associated with the effectiveness of sunitinib-targeted therapy on renal cell carcinoma. VEGFR SNPs are able to mediate the MAPK/ERK/STAT3 signaling pathway and therefore influence the effectiveness of sunitinib-targeted therapy, which makes them possible new therapeutic targets.

Inhibition of HL-60 cell growth via cell cycle arrest and apoptosis induction by a cycloartane-labdane heterodimer from Pseudolarix amabilis

Pseudolaridimer C (), a rarely encountered cycloartane-labdane Diels-Alder adduct was isolated from the cones of Pseudolarix amabilis. The structure and absolute configuration of were established by comprehensive NMR and CD spectral analysis. The WST-8 assay indicated that time and dose dependently inhibited the proliferation of human leukemia cells HL-60 at 1-10 μM. DAPI and Annexin V-FITC/PI double staining method, and DNA ladder experiments all proved that had significant dose-dependent effects on HL-60 cell apoptosis. A further mechanism study indicated that the apoptosis was associated with the cell cycle arrest during the G2/M phase, and the activation of caspase-9, -3, -7, and poly-(ADP-ribose)-polymerase (PARP).

The tyrosine kinase inhibitor, sunitinib malate, induces cognitive impairment in vivo via dysregulating VEGFR signaling, apoptotic and autophagic machineries

Chemobrain refers to a cluster of cognitive deficits which affects almost 4-75% of chemotherapy-treated cancer patients. Sunitinib, an FDA-approved multityrosine kinase inhibitor, is currently used in treating different types of tumors. Despite being regarded as targeted therapy which blunts sustained angiogenesis in cancer milieu through inhibiting vascular endothelial growth factor receptor 2 (VEGFR2) signaling, the latter has a cardinal role in cognition. Recent clinical reports warned that sunitinib adversely affected memory processing in cancer patients. Nevertheless, the underlying mechanisms have not been investigated yet. Hence, we explored the impact of a clinically relevant dose of sunitinib on memory processing in vivo and questioned the implication of VEGFR2 signaling, autophagy and apoptosis. Strikingly, sunitinib preferentially impaired spatial cognition as evidenced in Morris water maze, T-maze and passive avoidance task. Consistently, sunitinib degenerated cortical and hippocampal neurons as assessed by histopathological examination and toluidine blue staining. Ultrastructural examination also depicted chromatin condensation, mitochondrial damage and accumulated autophagosomes. Digging deeper, central VEGF/VEGFR2/mTOR signaling was robustly suppressed. Besides, sunitinib boosted cortical and hippocampal p53 and executioner caspase-3 and decreased nuclear factor kappa B and Bcl-2 levels promoting apoptotic cell death. It also profoundly impeded neuronal autophagic flux as shown by decreased beclin-1 and Atg5 and increased p62/SQTSM1 levels. To our knowledge, this is the first study to provide molecular insights into sunitinib-induced chemofog where impeded VEGFR2 signaling and autophagic and hyperactivated apoptotic machineries act in neurodegenerative concert. Importantly, our findings shed light on potential therapeutic strategies to be exploited in the management of sunitinib-induced chemobrain.

Hypothyroidism Side Effect in Patients Treated with Sunitinib or Sorafenib: Clinical and Structural Analyses

Tyrosine kinase inhibitors (TKIs) provide more effective targeted treatments for cancer, but are subject to a variety of adverse effects, such as hypothyroidism. TKI-induced hypothyroidism is a highly complicated issue, because of not only the unrealized toxicological mechanisms, but also different incidences of individual TKI drugs. While sunitinib is suspected for causing thyroid dysfunction more often than other TKIs, sorafenib is believed to be less risky. Here we integrated clinical data and in silico drug-protein interactions to examine the pharmacological distinction between sunitinib and sorafenib. Statistical analysis on the FDA Adverse Event Reporting System (FAERS) confirmed that sunitinib is more concurrent with hypothyroidism than sorafenib, which was observed in both female and male patients. Then, we used docking method and identified 3 proteins specifically binding to sunitinib but not sorafenib, i.e., retinoid X receptor alpha, retinoic acid receptors beta and gamma. As potential off-targets of sunitinib, these proteins are well known to assemble with thyroid hormone receptors, which can explain the profound impact of sunitinib on thyroid function. Taken together, we established a strategy of integrated analysis on clinical records and drug off-targets, which can be applied to explore the molecular basis of various adverse drug reactions.

Multikinase Inhibitors Induce Cutaneous Toxicity through OAT6-Mediated Uptake and MAP3K7-Driven Cell Death

The use of multikinase inhibitors (MKI) in oncology, such as sorafenib, is associated with a cutaneous adverse event called hand-foot skin reaction (HFSR), in which sites of pressure or friction become inflamed and painful, thus significantly impacting quality of life. The pathogenesis of MKI-induced HFSR is unknown, and the only available treatment options involve dose reduction or discontinuation of therapy, which have negative effects on primary disease management. To investigate the underlying mechanisms by which sorafenib promotes keratinocyte cytotoxicity and subsequent HFSR induction, we performed a transporter-directed RNAi screen in human epidermal keratinocytes and identified SLC22A20 (OAT6) as an uptake carrier of sorafenib. Further investigations into the intracellular mechanism of sorafenib activity through in situ kinome profiling identified the mitogen-activated protein kinase MAP3K7 (TAK1) as a target of sorafenib that induces cell death. Finally, we demonstrate that sorafenib induced keratinocyte injury in vivo and that this effect could be reversed by cotreatment with the OAT6 inhibitor probenecid. Collectively, our findings reveal a novel pathway that regulates the entry of some MKIs into keratinocytes and explains the basis underlying sorafenib-induced skin toxicity, with important implications for the therapeutic management of HFSR.

Induction of epithelial-mesenchymal transition via activation of epidermal growth factor receptor contributes to sunitinib resistance in human renal cell carcinoma cell lines

Sunitinib is widely used for treating renal cell carcinoma (RCC). However, some patients do not respond to treatment with this drug. We aimed to study the association between sunitinib sensitivity and epithelial-mesenchymal transition (EMT) regulation via epidermal growth factor receptor (EGFR) signaling, which is a mechanism of resistance to anticancer drugs. Three RCC cell lines (786-O, ACHN, and Caki-1) were used, and then we evaluated cell viability, EMT regulatory proteins, and signal transduction with sunitinib treatment. Cell viability of 786-O cells was maintained after treatment with sunitinib. After treatment with sunitinib, EGFR phosphorylation increased in 786-O cells, resulting in an increase in the phosphorylation of extracellular signal-regulated kinase, nuclear translocation of β-catenin, and expression of mesenchymal markers. These results suggest that sunitinib induced EMT via activation of EGFR in 786-O cells, but not in ACHN and Caki-1 cells. Caki-1/SN cells, a resistant cell line generated by continuous exposure to sunitinib, displayed increased phosphorylation of EGFR. Cell viability in the presence of sunitinib was decreased by erlotinib, as the selective inhibitor of EGFR, treatment in 786-O and Caki-1/SN cells. Similarly, erlotinib suppressed sunitinib-induced EGFR activation and upregulated mesenchymal markers. Thus, we postulate that resistance to sunitinib in RCC may be associated with EMT caused by activation of EGFR.

Constitutive control of AKT1 gene expression by JUNB/CJUN in ALK+ anaplastic large-cell lymphoma: a novel crosstalk mechanism

Anaplastic lymphoma kinase-positive (ALK+) anaplastic large-cell lymphoma (ALCL) is an aggressive T-cell non-Hodgkin lymphoma characterized by the t(2;5), resulting in the overexpression of nucleophosmin (NPM)-ALK, which is known to activate the phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway, resulting in cell cycle and apoptosis deregulation. ALK+ ALCL is also characterized by strong activator protein-1 (AP-1) activity and overexpression of two AP-1 transcription factors, CJUN and JUNB. Here, we hypothesized that a biologic link between AP-1 and AKT kinase may exist, thus contributing to ALCL oncogenesis. We show that JUNB and CJUN bind directly to the AKT1 promoter, inducing AKT1 transcription in ALK+ ALCL. Knockdown of JUNB and CJUN in ALK+ ALCL cell lines downregulated AKT1 mRNA and promoter activity and was associated with lower AKT1 protein expression and activation. We provide evidence that this is a transcriptional control mechanism shared by other cell types even though it may operate in a way that is cell context-specific. In addition, STAT3 (signal transducer and activator of transcription 3)-induced control of AKT1 transcription was functional in ALK+ ALCL and blocking of STAT3 and AP-1 signaling synergistically affected cell proliferation and colony formation. Our findings uncover a novel transcriptional crosstalk mechanism that links AP-1 and AKT kinase, which coordinate uncontrolled cell proliferation and survival in ALK+ ALCL.

Management of dose variability and side effects for individualized cancer pharmacotherapy with tyrosine kinase inhibitors

Molecular-targeted therapies with tyrosine kinase inhibitors (TKIs) have provided a major breakthrough in cancer treatment. These agents are given orally and demonstrated to be substrates for drug transporters. In clinical settings, TKIs are mainly used at a fixed dose, but wide interpatient variability has been observed in their pharmacokinetics and/or pharmacodynamics. Genetic polymorphisms of ABC transporters, drug-drug interaction and adherence are among the factors causing such variation. To overcome these problems, therapeutic drug monitoring has been applied in clinical practice for patient care. Skin disorders are frequently observed as adverse drug reactions when using TKIs, and are commonly managed by symptomatic therapy based on clinical experience. Recent studies have provided some insights into the molecular mechanisms underlying skin disorders induced by TKIs. This review article summarizes the accumulated clinical and basic pharmacological evidence of TKIs, focusing on erlotinib, sorafenib and sunitinib.