Connexin 43 enhances Bax activation via JNK activation in sunitinib-induced apoptosis in mesothelioma cells.

The constituent protein of gap junctions, connexin (Cx), interacts with various proteins via its C-terminus region, including kinases, cell-adhesion proteins, and a pro-apoptotic protein, Bax. This molecular interaction may affect expression and functioning of the interacting proteins and modulate the cellular physiology. In our previous work, Cx43 was found to interact directly with Bax and in the presence of sunitinib, lead to the Bax-mediated apoptosis in mesothelioma cells. In this study, we investigated the mechanism of how Cx43 promotes Bax-mediated apoptosis using the same cell line. Treatment with sunitinib increased the expression of the active conformation of the Bax protein, which was predominantly localized at the mitochondria, only in Cx43-transfected cells. Bax oligomerization and decrease in the mitochondrial membrane potential were also observed. The involvement of c-Jun N-terminal kinase (JNK) in the interaction of Cx43 and Bax was further examined. Treatment with sunitinib increased the expression of phosphorylated (active) form of JNK only in the Cx43-transfected cells. Phosphorylated JNK and active Bax were co-localized, and the co-localization was suppressed by the knockdown of Cx43. Moreover, JNK inhibition clearly suppressed Bax activation. In conclusion, we identified a novel Cx43-JNK-Bax axis regulating the process of apoptosis for the first time.

Effect of enhanced expression of connexin 43 on sunitinib-induced cytotoxicity in mesothelioma cells.

Connexin (Cx) makes up a type of intercellular channel called gap junction (GJ). GJ plays a regulatory role in cellular physiology. The Cx expression level is often decreased in cancer cells compared to that in healthy ones, and the restoration of its expression has been shown to exert antiproliferative effects. This work aims to evaluate the effect of the restoration of connexin 43 (Cx43) (the most ubiquitous Cx subtype) expression on sunitinib (SU)-induced cytotoxicity in malignant mesothelioma (MM) cells. Increased Cx43 expression in an MM cell line (H28) improved the ability of SU to inhibit receptor tyrosine kinase (RTK) signaling. Moreover, higher Cx43 expression promoted SU-induced apoptosis. The cell viability test revealed that Cx43 enhanced the cytotoxic effect of SU in a GJ-independent manner. The effect of Cx43 on a proapoptotic factor, Bax, was then investigated. The interaction between Cx43 and Bax was confirmed by immunoprecipitation. Furthermore, higher Cx43 expression increased the production of a cleaved (active) form of Bax during SU-induced apoptosis with no alteration in total Bax expression. These findings indicate that Cx43 most likely increases sensitivity to SU in H28 through direct interaction with Bax. In conclusion, we found that Cx43 overcame the chemoresistance of MM cells.

Increased expression of the histamine H4 receptor following differentiation and mediation of the H4 receptor on interleukin-8 mRNA expression in HaCaT keratinocytes.

Recent in vivo studies have demonstrated involvement of the histamine H4 receptor in pruritus and skin inflammation. We previously reported that an H4 receptor antagonist attenuated scratching behaviour and improved skin lesions in an experimental model of atopic dermatitis. We also reported the expression of the H4 receptor in human epidermal tissues. In this study, we investigated the expression of H4 receptor mRNA and the function of the receptor in a culture system that mimics in vivo inflammation on the HaCaT human keratinocyte cell line. Increased expression of the H4 receptor was observed in HaCaT cells following differentiation. Treatment of HaCaT cells with histamine and TNFα enhanced the mRNA expression of interleukin (IL)-8. These increases in expression were significantly inhibited by the H4 receptor antagonist JNJ7777120. Our results indicate that IL-8 mRNA expression might be enhanced by histamine and TNFα via H4 receptor stimulation in keratinocytes.

The pharmacological differences in antianginal effects of long-lasting calcium channel blockers: azelnidipine and amlodipine.

We examined antianginal effects of azelnidipine and amlodipine in an arginine vasopressin-induced rat anginal model. Oral administration of azelnidipine or amlodipine produced long lasting inhibition of arginine vasopressin-induced ST-segment depression in electrocardiogram. The degrees of inhibition with azelnidipine at doses of 1 and 3 mg/kg were comparable to those with amlodipine at 3 and 10 mg/kg. Both drugs lowered mean blood pressure in a dose-related manner, whereas only azelnidipine decreased heart rate. Azelnidipine at 3 mg/kg and amlodipine at 10 mg/kg produced a similar decrease in the rate pressure product, an index for cardiac oxygen consumption. Their inhibitory effects on calcium-induced vascular contraction were compared in isolated porcine coronary arteries. Both drugs produced a slow-developing inhibition of calcium-induced contraction. Although their inhibitory effects were similar, the way the both drugs inhibited calcium-induced contraction differed with each other. After removing the drug from bathing solution, the inhibitory effects of azelnidipine were not blunted but were sustained for a long time, which indicates that azelnidipine has high vascular affinity. On the other hand, those of amlodipine were rapidly blunted. These results suggest that the mechanisms underlying antianginal effects of azelnidipine differ from those of amlodipine. The antianginal effect with azelnidipine may be accounted for by its high affinity to the coronary blood vessels and the heart rate slowing effect, both of which are not shared with amlodipine.

Sex differences in stress reactivity of hippocampal BDNF in mice are associated with the female preponderance of decreased locomotor activity in response to restraint stress.

The incidence and prevalence of depression is higher in women than in men, but the cause of this sex discrepancy remains unknown. Brain-derived neurotrophic factor (BDNF) is a key protein for maintaining neuronal integrity. The purpose of this study was to investigate the female preponderance in behavioral responsivity to restraint stress focusing on the stress reactivity of BDNF in the hippocampus. Male and female ICR mice were exposed to a 3-h session of restraint stress. Plasma corticosterone was measured by high-performance liquid chromatography. BDNF mRNA expression in the whole hippocampus was measured by quantitative real-time reverse transcription-polymerase chain reaction. Wheel-running activity was monitored during the dark period. In response to restraint stress, the increase in levels of serum corticosterone was higher in female than in male mice. Restraint stress resulted in decreased voluntary wheel-running behavior that was greater in female than male animals. In addition to these sex differences in stress reactivity, we found a significant sex difference in BDNF levels in the hippocampus of restraint-stressed mice; total BDNF levels significantly decreased in female mice, but not in male mice in response to the stress. Furthermore, BDNF exon I and IV mRNA expression also showed the same tendency. These data indicate that the reduction in levels of voluntary wheel-running activity in response to stress can be significantly influenced by sex. Moreover, our findings suggest a link between the sex differences in this behavioral response to stress and differential stress reactivity in the production of BDNF in the hippocampus.

The effect of sex hormones on peroxisome proliferator-activated receptor gamma expression and activity in mature adipocytes.

Peroxisome proliferator-activated receptor (PPAR) γ plays a major role in the regulation of lipid and carbohydrate metabolism. Pioglitazone is a PPARγ agonist that is widely used for the treatment of type 2 diabetes mellitus. However, female patients have been reported to experience stronger efficacy and adverse effects than male patients. This study evaluated the effects of sex hormones on PPARγ expression and activity in adipocytes. Mouse 3T3-L1 preadipocytes were used after being grown into matured adipocytes. The sex hormones 17ß-estradiol (E2), testosterone (T), or 5α-androstan-17ß-ol-3-one (dihydrotestosterone; DHT) were added to the matured adipocytes and the cells were then maintained for short (24-72 h) or long (1- or 2-weeks) periods. E2 significantly upregulated PPARγ protein expression in a concentration-dependent manner after extended exposure, whereas T and DHT did not have such an effect. When cells were co-treated with pioglitazone and E2, PPARγ protein expression significantly increased in an E2-dependent manner, whereas this expression seemed to be reduced by pioglitazone mono-treatment and co-treatment with DHT at higher concentrations. The secretion levels of adiponectin protein, a major indicator of PPARγ activity, were significantly decreased by DHT, but were not affected by E2. Finally a luciferase assay was performed using a PPAR response element-Luk reporter gene. Transcriptional activity was not changed by any of single sex hormone treatment, but was significantly downregulated by co-treatment with pioglitazone and DHT. Taken together, our results suggest that sex hormones may influence PPARγ expression and function, which may explain the observed sex-specific different effect of pioglitazone.

[Accidents during bathing].

Sudden death during bathing accounts for 10 to 15% of all out-of hospital cardiac arrests in Japan. Surveys in Tokyo revealed 1,085 victims of accidents during bathing transported by ambulance from October 1999 to March 2000. 53% of them were cardiac arrest and 25% were those who needed rescue from bath tub because of consciousness disturbance (rescued group). Clinical observation of the rescued group patients indicated they suffered from transient loss of consciousness probably because of elevated body temperature. The current hypothesis of the accidents during bathing is a unique type of heat illness exposed by high water temperature(41-43 degrees C). Geriatric population is vulnerable to the bathing induced heat illness.

Increased expression of the histamine H4 receptor subtype in hypertrophic differentiation of chondrogenic ATDC5 cells.

Histamine has been regarded as an inflammatory mediator of arthritic disorders. We have previously reported that the expression of histamine H(4) receptor (H(4)R) mRNA in synovial tissues was significantly higher in patients with osteoarthritis (OA) compared to those with rheumatoid arthritis. Chondrocyte hypertrophy and endochondral ossification are essential processes in pathologic disorders such as osteophyte formation during OA progression. In the present study, we examined the expression of H(4) R during differentiation into hypertrophic chondrocytes in the ATDC5 cells, a widely used in vitro model of chondrogenic differentiation. Quantitative reverse transcription polymerase chain reaction showed that the levels of histidine decarboxylase and H(4)R mRNA on ATDC5 cells were increased in a time-dependent manner during the culture period. By contrast, the expressions of H(1)R and H(2)R were not increased from day 7 onwards. The mRNA expression of the hypertrophic chondrocyte marker type X collagen (COL X) was increased markedly from 14 to 21. Immunocytochemical analysis indicated that H(4)R staining was strongly immunoreactive on the plasma membrane of ATDC5 cells. Flow cytometry showed increased expression of H(4)R and COL X protein in ATDC5 chondrocytes. Furthermore, the majority of the COL X-positive cells expressed H(4) R throughout the culture period. In summary, we showed for the first time that H(4)R is expressed in ATDC5 chondrocytes. Moreover, we found that most hypertrophic chondrocytes express H(4)R, suggesting that this receptor might be associated with the differentiation of chondrocytes into hypertrophic cells, which are abnormally observed in joint lesions in OA.

New 2-aryl-1,4-naphthoquinone-1-oxime methyl ether compound induces microtubule depolymerization and subsequent apoptosis.

In this study, we describe the antitumor activity of QO-1, one of the new 2-aryl-1,4-naphthoquinone-1-oxime methyl ether derivatives. QO-1 is a derivative of macarpine, a natural occurring product from Rutaceae plant. It could potently inhibit cell growth when tested on 19 cancer cell lines. To investigate its mechanism, two cell lines (HeLa and MCF-7) sensitive to QO-1 were selected. Based on flow cytometry, it was found to induce G(2)/M-phase arrest. Moreover, it could cause microtubule depolymerization both in vitro and in vivo. On the other hand, QO-1 activated spindle assembly checkpoint (SAC) proteins. Expression of Bub1, one of the SAC, was gradually increased, reaching a peak after 16 - 20 h, and then gradually decreased. Instead, QO-1 increased the sub-G(1) population, which suggested a cell death population. Actually, expression of Bcl-2 family proteins and activation of caspase-3/7 were evidences of apoptosis. Consistent with these results, cells with DNA fragmentation and multinucleated cells were increased time-dependently after QO-1 exposure. In conclusion, QO-1 has promising antitumor effects via microtubule depolymerization.

Lower expression of histamine H4 receptor in synovial tissues from patients with rheumatoid arthritis compared to those with osteoarthritis.

The aim of this study is to compare the expression level of histamine H(4) receptor (H(4)R) mRNA in synovial tissues of rheumatoid arthritis (RA) and osteoarthritis (OA) patients, and to study correlation of results with clinical characteristics of patients with RA. Synovial tissues were obtained from 7 RA and 7 OA patients undergoing artificial arthroplasty. Serum levels of erythrocyte sedimentation rate, C-reactive protein, matrix metalloproteinase-3 (MMP-3), rheumatoid factors, and cyclic citrullinated peptide antibodies were determined. The expression of H(4)R mRNA in synovial tissues was determined by real-time polymerase chain reaction. Expression of H(1)R and H(4)R mRNA were significantly lower in RA compared with OA patients (P < 0.005), while expression of H(2)R mRNA was comparable in both. While a significant negative correlation was found between H(4)R expression and serum MMP-3 concentration (r = -0.70, P < 0.05), no correlation was found between MMP-3 and H(1)R (r = -0.52) or H(2)R (r = 0.23). This study supports the supposition that H(4)R in synovial tissue may play a role in cartilage and bone destruction by influencing the secretion of MMP-3 in patients with RA.

Association of Rsa polymorphism of the estrogen receptor-ß gene with rheumatoid arthritis.

To investigate the possible influence of the single nucleotide polymorphism (SNP) of the estrogen receptor-ß gene, rs1256049 (Rsa) in exon 5, on the frequency of rheumatoid arthritis (RA), 263 RA patients and 174 control subjects with osteoarthritis (OA) were recruited. Rsa polymorphism was detected using a PCR-RFLP, Polymerase Chain Reaction-Restriction Fragment Length Polymorphism method. The occurrence of both mutant allele (G) and genotype (GG) were significantly higher in RA than in OA patients (allele P = 0.008, OR: 1.501, 95%CI: 1.12-2.02). In RA patients, GG genotype frequency was higher in severe RA patients than mild RA patients. Moreover, there was significant difference between severe RA patients and OA patients (P = 0.009), also the allele distribution was significant different between severe RA, mild RA, and OA patients (P = 0.025, 95%CI = 0.61-0.93). With respect to gender, GG genotype was statistically more frequent in female RA patients than that of OA, while such an association was not observed in men. Above all, the presence of the GG genotype could be a risk factor for RA and such trend might be different in gender, although additional larger scale study is needed.

Attempt at cloning high-quality goldfish breed 'Ranchu' by fin-cultured cell nuclear transplantation.

The viability of ornamental fish culture relies on the maintenance of high-quality breeds. To improve the profitability of culture operations we attempted to produce cloned fish from the somatic nucleus of the high-quality Japanese goldfish (Carassius auratus auratus) breed 'Ranchu'. We transplanted the nucleus of a cultured fin-cell from an adult Ranchu into the non-enucleated egg of the original goldfish breed 'Wakin'. Of the 2323 eggs we treated, 802 underwent cleavage, 321 reached the blastula stage, and 51 reached the gastrula stage. Two of the gastrulas developed until the hatching stage. A considerable number of nuclear transplants retained only the donor nucleus. Some of these had only a 2n nucleus derived from the same donor fish. Our results provide insights into the process of somatic cell nuclear transplantation in teleosts, and the cloning of Ranchu.

2-Aryl-1,4-naphthoquinone-1-oxime methyl ethers: their cytotoxic activity.

Preliminary examination for the structure-activity relationship of quinone monooxime derivatives on cytotoxicity against HeLa S3 cell and further trials using eight different cell lines suggested that 2-aryl-6,7-methylenedioxy-1,4-naphthoquinone-1-oxime methyl ethers, carrying 2-methoxy-4,5-methylenedioxyphenyl, 7-methoxy-2-methylbenzofuran-4-yl, and 2-methoxycarbonyl-3,4-dimethoxyphenyl as the 2-aryl substituent, were potential candidates for anti-cancer drugs.

[Mechanism of sex differences and the clinical significance of PPARgamma targeted drugs].

Peroxisome proliferator-activated receptor (PPAR) gamma is the nuclear receptor which mainly distributes in adipose tissues. It plays a key role in the differentiation of adipocytes. In Japan, pioglitazone hydrochloride (Actos) is the only drug which targets PPARgamma among antidiabetic drugs. It had been reported that there are sex differences in pharmacological and side effects of pioglitazone hydrochloride. This is a brief overview on the mechanism of sex differences of this drug, especially focusing on the role of sex hormones on PPARgamma expression. Moreover, we also considered about the effects of such differences on clinical applications from our research of prescribing data in 20 hospitals and also the result of PRospective ACTos practICAL experience (PRACTICAL).

[Anti-diabetic effect of ethanol extract of Cyclolepis genistoides D. Don (Palo azul), made in Paraguay].

Extract of Cyclolepis genistoides D. Don (vernacular name Palo azul; Palo) are traditionally consumed in the Republic of Paraguay in South America for the treatment of diabetes and kidney disease, and is sold in Japan as dietary supplement. This study aimed to elucidate the mechanism of anti-diabetes activity of Palo, especially focused on insulin resistance. Palo promoted adipocytes differentiation and regulated adipokine profiles in 3T3-L1 adipocytes by modulation of PPARγ, a major regulator of adipose differentiation. Human adipocyte showed almost similar profile with 3T3-L1 against Palo treatment. Furthermore, Palo treatment (250 or 1000 mg/kg) was performed with C57BL/6J mice for 14 weeks, being fed high-fat-diet (HFD60) simultaneously. Palo 250 mg/kg exhibited a tendency to decrease subcutaneous adipose volume along with increase of PPARγ and its target, adiponectin mRNA expression. In addition, as the other insulin targeted cell, effect on muscle differentiation was examined. Palo increased differentiation of C2C12 mouse muscle myoblasts by increase of IGF-1, myogenin, and myosine heavy chain (MHC) as well as 5'-AMP-activated protein kinase (AMPK) activation. Palo subsequently promoted myotube formation under differentiation condition. From the above, it was clarified that Palo acts variously on the differentiation and maturation of both adipocytes and muscle cells, and from the viewpoint of the regulatory mechanism for adipocytes, PPARγ-inducing action was shown to be a mechanism that acts across species.

Endoscopic removal of foreign bodies: A retrospective study in Japan.

BACKGROUND: The ingestion of foreign bodies (FBs) and food bolus impaction (FBI) in the digestive tract are commonly encountered clinical problems. Methods to handle such problems continue to evolve offering advantages, such as the avoidance of surgery, reduced cost, improved visualization, reduced morbidity, and high removal success rate. However, to date, no studies have evaluated the endoscopic management of FBs in Japan. AIM: To elucidate level of safety and efficacy in the endoscopic management of FBs and FBI. METHODS: A total of 215 procedures were performed at Keio University Hospital between November 2007 and August 2018. Data were collected from medical charts, and endoscopic details were collected from an endoscopic reporting system. Procedures performed with a flexible gastrointestinal endoscope were only taken into account. Patients who underwent a technique involving FB or FBI from the digestive tract were only included. Data on patient sex, patient age, outpatient, inpatient, FB type, FB location, procedure time, procedure type, removal device type, success, and technical complications were reviewed and analyzed retrospectively. RESULTS: Among the 215 procedures, 136 (63.3%) were performed in old adults (≥ 60 years), 180 (83.7%) procedures were performed in outpatients. The most common type of FBs were press-through-pack (PTP) medications [72 (33.5%) cases], FBI [47 (21.9%)], Anisakis parasite (AP) [41 (19.1%) cases]. Most FBs were located in the esophagus [130 (60.5%) cases] followed by the stomach [68 (31.6%) cases]. AP was commonly found in the stomach [39 (57.4%) cases], and it was removed using biopsy forceps in 97.5% of the cases. The most common FBs according to anatomical location were PTP medications (40%) and dental prostheses (DP) (40%) in the laryngopharynx, PTP (48.5%) in the esophagus, AP (57.4%) in the stomach, DP (37.5%) in the small intestine and video capsule endoscopy device (75%) in the colon. A transparent cap with grasping forceps was the most commonly used device [82 (38.1%) cases]. The success rate of the procedure was 100%, and complication were observed in only one case (0.5%). CONCLUSION: Endoscopic management of FBs and FBI in our Hospital is extremely safe and effective.

Lower frequency of daily teeth brushing is related to high prevalence of cardiovascular risk factors.

This study sought to investigate relationships between frequency of daily teeth brushing and prevalences of diabetes mellitus, hypertension and dyslipidemia. Subjects were 54,551 residents of Chiba City, Japan (20,155 men and 34,396 women) who underwent routine health examinations in 2004. Diabetes mellitus was defined as a fasting plasma glucose level > or =126 mg/dl or a non-fasting plasma glucose level > or =200 mg/dl and/or receiving treatment for diabetes. Hypertension was defined as systolic blood pressure (SBP) > or =140 mmHg, diastolic blood pressure (DBP) > or =90 mmHg and/or receiving treatment for hypertension. Dyslipidemia was defined according to the two criteria: high triglyceride and/or low high density lipoprotein cholesterol (TG > or = 150 mg and/or HDL-C < 40 mg/dl), and high total cholesterol (TC > or = 220 mg/dl). According to Pearson's chi-square tests and logistic regression analysis adjusted for age, BMI, smoking habit, alcohol consumption and daily walking time, lower frequency of teeth brushing is related to higher prevalences of diabetes mellitus, hypertension and high TG and/or low HDL-C, in both men and women. Total cholesterol status, however, showed no significant relationship. Maintaining good oral hygiene by regular teeth brushing may prevent type 2 diabetes, hypertension and dyslipidemia.

Effect of obesity on incidence of type 2 diabetes declines with age among Japanese women.

AIMS: The present study sought to investigate whether the effect of obesity on the incidence of type 2 diabetes varies with age among Japanese. METHODS: Employing two independent cohorts, one in Chiba City from 1994 to 2005 and the other in Kashiwa City from 2002 to 2006, the combined effect of body mass index (BMI) and age on the incidence of type 2 diabetes was evaluated by Cox regression analysis. A total of 37,564 and 26,959 subjects were enrolled in the cohorts and the follow-up rate was 94.7% and 93.3%, respectively. RESULTS: In the Chiba cohort, the hazard ratio for incidence of type 2 diabetes was significantly higher in obese subjects (25.0 kg/m(2) < or = BMI) than in normal weight subjects (18.5 kg/m(2) < or = BMI < 25.0 kg/m(2)) across all age groups, with the highest hazard ratio observed in the youngest group aged 40-59 years. In the Kashiwa cohort, the hazard ratio was also significantly higher in obese subjects than in normal weight subjects in men aged 40-59 and 70-79 years and in women aged 40-59 years. Analysis for the interaction between age groups and obese subjects versus normal weight subjects revealed significant weakening of the effect of obesity in women in both cohorts in subjects aged 60-69 and 70-79 years compared to younger subjects aged 40-59 years. In men, however, a significant weakening of the effect was observed only in subjects aged 60-69 years in the Chiba cohort. The interaction between four BMI categories including an extremely obese group (30.0 kg/m(2) < or = BMI) and age category was significant in women (P < 0.001) but not in men (P = 0.113) in the Chiba cohort. CONCLUSION: Based on data from the two independent cohorts, the effect of obesity on the incidence of type 2 diabetes was found to decline with age in Japanese women but not in men.

[Gender differences in pharmacokinetics of anesthetics].

The gender aspect in pharmacokinetics and pharmacodynamics of anesthetics has attracted little attention. Knowledge of previous work is required to decide if gender-based differences in clinical is justified. Females have 20-30% greater sensitivity to the muscle relaxant effects of vecuronium and rocuronium. When rapid onset of or short duration of action is very important, gender-modified dosing may be considered. Males are more sensitive than females to propofol. It may therefore be necessary to decrease the propofol dose by 30-40% in males compared with females in order to achieve similar recovery times. Females are more sensitive than males to opioid receptor agonists, as shown for morphine as well as for pentazocin. On the other hand, females may experience respiratory depression and other adverse effects more easily if they are given the same doses as males. These examples illustrate that gender should be taken into account as a factor that may be predictive for the dosage of several anesthetic drugs. Moreover, there is an obvious need for more research in this area in order to further optimize drug treatment in anesthesia.

Trichostatin A modulates cellular metabolism in renal cell carcinoma to enhance sunitinib sensitivity.

Although sunitinib is the first-line drug for progressive renal cell carcinoma (RCC), most patients experience its tolerance. One possible way of overcoming drug resistance is combination therapy. Epigenetic modifier is one of the candidate drug group. A recent evidence suggests that cell metabolism is regulated by epigenetic mechanisms. Epigenetic abnormalities lead to changes in metabolism and may contribute to drug resistance and progression of RCC. Consequently, we investigated whether trichostatin A (TSA), a potent histone-deacetylase (HDAC) inhibitor, alters sunitinib-induced cytotoxicity and metabolism in RCC cells at epigenetic regulatory concentrations. Combined metabolome and transcriptome analysis suggested that TSA impacts on energy productive metabolic pathways, such as those involving TCA cycle and nucleotide metabolism especially for increase of hyperphosphorylated form. Combination of sunitinib and TSA increased cell death with PARP cleavage, an early marker of mitochondrial apoptosis, whereas receptor tyrosine kinase signaling, which is the target of sunitinib, was not altered by TSA. Finally, the established sunitinib resistant-RCC cell (786-O Res) was also exposed to sunitinib and TSA combination, resulting in significant growth inhibition. In summary, it was suggested that TSA reduces sunitinib resistance by triggering intracellular metabolome shifts regarding energy metabolism, that is the first recognized mechanism as an HDAC inhibitor.