Restoration of p53 acetylation by HDAC inhibition permits the necrosis/apoptosis switch of pancreatic ainar cell during experimental pancreatitis in mice

Oncogenic BRAF and p53 Interplay in Melanoma Cells and the Effects of the HDAC Inhibitor ITF2357 (Givinostat)

Oncogenic BRAF mutations have been widely described in melanomas and promote tumour progression and chemoresistance. We previously provided evidence that the HDAC inhibitor ITF2357 (Givinostat) targets oncogenic BRAF in SK-MEL-28 and A375 melanoma cells. Here, we show that oncogenic BRAF localises to the nucleus of these cells, and the compound decreases BRAF levels in both the nuclear and cytosolic compartments. Although mutations in the tumour suppressor p53 gene are not equally frequent in melanomas compared to BRAF, the functional impairment of the p53 pathway may also contribute to melanoma development and aggressiveness. To understand whether oncogenic BRAF and p53 may cooperate, a possible interplay was considered in the two cell lines displaying a different p53 status, being p53 mutated into an oncogenic form in SK-MEL-28 and wild-type in A375 cells. Immunoprecipitation revealed that BRAF seems to preferentially interact with oncogenic p53. Interestingly, ITF2357 not only reduced BRAF levels but also oncogenic p53 levels in SK-MEL-28 cells. ITF2357 also targeted BRAF in A375 cells but not wild-type p53, which increased, most likely favouring apoptosis. Silencing experiments confirmed that the response to ITF2357 in BRAF-mutated cells depends on p53 status, thus providing a rationale for melanoma-targeted therapy.

HDACs/mTOR inhibitor synergizes with pyrotinib in HER2-positive pancreatic cancer through degradation of mutant P53

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC), as a highly lethal malignancy with high mortality, lacks of effective treatment. Canonical therapeutic targets in PDAC demand further verification among which HER2 receptor tyrosine kinase inhibitor pyrotinib as treatment targets has not be decided.

METHODS

Anti-PDAC efficacy of pyrotinib was evaluated both in vitro and in vivo using both cell lines and patient-derived xenografts. By screening a large-scale library of 1453 compounds, we identified HDACs/mTOR inhibitor 1 as a promising candidate to synergize with pyrotinib. The combination therapy was evaluated in vitro and in vivo in multiple cell lines and animal models. Furthermore, RNA-seq analysis was performed to reveal the latent molecular mechanism of combination therapy.

RESULTS

In our study, pyrotinib monotherapy was found to be inefficient to anti-PDAC which exhibited limited anti-proliferation effect in vitro and in vivo. Through therapy combined with HDACs/mTOR inhibitor 1, pyrotinib triggered intense apoptosis in PDAC both in cell lines and animal models. Mechanistic analyses revealed that mutant P53 degradation mediated by HDAC inhibition synergized with HER2 and mTOR inhibition.

CONCLUSIONS

In conclusion, identification of HDACs/mTOR inhibitor as a synergistic inhibitor, provides a potent therapeutic strategy that targets HER2-positive pancreatic cancer.

The anti-inflammatory mechanism of SAHA in acute pancreatitis through HDAC5/SLIT2/Akt/β-catenin axis

Acute pancreatitis (AP) is widely recognized to be an inflammation-related disease, in which HDAC was upregulated. The anti-inflammatory role of suberoylanilide hydroxamic acid (SAHA), a HDAC inhibitor, has been documented. In this context, this research was implemented to figure out whether SAHA manipulated inflammation in AP. Subsequent to induction of AP mouse model, HDAC5 expression was detected. The binding of HDAC5 and SLIT2 was detected by Co-Immunoprecipitation and ChIP assays. SAHA treatment and gain- and loss-of-function approaches were used in AP mice and lipopolysaccharide (LPS)-induced pancreatic acinar cells. In mice, biochemical methods were implemented to measure activities of pancreatic lipase, trypsin, MPO and pancreatic edema, TUNEL staining to determine pancreatic cell apoptosis, and flow cytometry to assess the total number of leukocytes and neutrophils in pancreas. In pancreatic acinar cells, CCK-8 was performed to evaluate cell viability. HDAC5 exhibited overexpression in AP mice. Mechanical analysis showed that HDAC5 facilitated SLIT2 deacetylation to downregulate SLIT2, thus activating Akt/β-catenin pathway in pancreatic acinar cells. SAHA treatment, HDAC5 silencing, or SLIT2 overexpression diminished inflammation in AP in vivo and in vitro. SAHA treatment, HDAC5 silencing, or SLIT2 overexpression reduced activities of pancreatic lipase, trypsin, MPO, pancreatic edema, and cell apoptosis in AP mice as well as elevated viability of LPS-induced pancreatic acinar cells. SAHA might exert anti-inflammatory effects in AP mice via HDAC5/SLIT2/Akt/β-catenin axis.

Escin Sodium Improves the Prognosis of Acute Pancreatitis via Promoting Cell Apoptosis by Suppression of the ERK/STAT3 Signaling Pathway

Acute pancreatitis (AP), an inflammatory disorder of the pancreas, can cause systemic inflammatory responses. Escin Sodium (ES), a natural mixture of triterpene saponins extracted from the dry ripe fruit of Fructus Aesculi or horse chestnut crude, has been demonstrated to have antiedematous, anti-inflammatory, and antiexudative effects. We here aim to investigate the effects of ES pretreatment on AP in vivo and in vitro and explore its potential molecular mechanism. In the present study, we demonstrated that ES pretreatment could apparently decrease amylase and lipase, downregulate inflammatory cytokines, and attenuate pancreatic damage. Additionally, the increased expression of apoptotic-related proteins and the results of flow cytometry demonstrated the effects of ES on promoting apoptosis in acinar cells. Moreover, ES could enhance mitochondrial membrane potential (MMP, ΔΨm) and reactive oxygen species (ROS) level and reduce intracellular calcium concentration, which are closely related to mitochondrial-mediated death. The effect of ES pretreatment on acinar cell apoptosis was furtherly confirmed by the regulatory pathway of the ERK/STAT3 axis. These results suggest that ES attenuates the severity of AP by enhancing cell apoptosis via suppressing the ERK/STAT3 signaling pathway. These findings provide evidence for ES which is treated as a novel and potent therapeutic for the treatment of AP.

Ketoplatin in triple-negative breast cancer cells MDA-MB-231: High efficacy and low toxicity, and positive impact on inflammatory microenvironment

Triple-negative breast cancer (TNBC) shares the molecular features facilitating epithelial-to-mesenchymal transition (EMT), which contributed to tumor invasion and metastasis. A platinum(IV) conjugate ketoplatin deriving from FDA-approved drugs cisplatin and ketoprofen was designed and prepared to enhance antitumor activity and suppress EMT in TNBC via positive impact on inflammatory microenvironment by modulating COX-2 signal. As a prodrug, ketoplatin afforded 50.26-fold higher cytotoxicity than cisplatin against TNBC mesenchymal-stem cell-like MDA-MB-231 cells, partly attributing to its dramatic increase of cellular uptake and DNA damage. More importantly, EMT progress in MDA-MB-231 was markedly restrained by ketoplatin, resulting from the suppression of vimentin and N-cadherin mediated by down-regulated COX-2. Further in vivo investigation exhibited that ketoplatin effectively inhibited tumor growth and reduced systemic toxicity compared to cisplatin. Overall, ketoplatin possessed high antitumor activity and low toxicity against TNBC MDA-MB-231 in vitro and in vivo.