BTK Modulates p53 Activity to Enhance Apoptotic and Senescent Responses

p53 is a tumor suppressor that prevents the emergence of transformed cells by inducing apoptosis or senescence, among other responses. Its functions are regulated tightly by posttranslational modifications. Here we show that Bruton's tyrosine kinase (BTK) is a novel modulator of p53. We found that BTK is induced in response to DNA damage and p53 activation. BTK induction leads to p53 phosphorylation, which constitutes a positive feedback loop that increases p53 protein levels and enhances the transactivation of its target genes in response to stress. Inhibiting BTK reduced both p53-dependent senescence and apoptosis. Further, BTK expression also upregulated DNA damage signals and apoptosis. We conclude that despite being involved in oncogenic signals in blood malignancies, BTK has antineoplastic properties in other contexts, such as the enhancement of p53's tumor suppressor responses. Along with evidence that BTK expression correlates with good prognosis in some epithelial tumors, our findings may encourage a reevaluation of the clinical uses of BTK inhibitors in cancer therapy

Mutation frequencies in endometrial cancer patients of different ethnicities and tumor grades: An analytical study

Background: Endometrial carcinoma is a predominant health problem for women worldwide. However, there is a lack of data on genetic mutation frequencies in endometrial cancer patients of different ethnicities and tumor grades. Objective: The objective of this study is to provide data regarding mutation frequencies in endometrial cancer patients of different ethnic groups and tumor grades by analyzing large-scale cancer genomic datasets of a database. Materials and Methods: The following databases of cBioPortal were explored for possible mutation frequency variations in endometrial cancer patients: the Uterine Corpus Endometrial Carcinoma (TCGA, PanCancer Atlas) database for ethnicity-based studies; the Uterine Corpus Endometrial Carcinoma (TCGA, Nature 2013) database for tumor grade-based study; and GDC Data Portal database for calculating survival rates using the Kaplan–Meier method. Results: PTEN mutation frequency was almost identical in all ethnic groups studied (White, Black/African American, Asian, Native Hawaiian or other Pacific Islander, and American Indian or Asian Native). PIK3CA and ARID1A mutation frequencies were higher in White and Asian patients compared with other ethnicities; TP53 and FAT1 mutation frequencies were higher in Black/African Americans; and CTNNB1 and RYR2 mutation frequencies were higher Native Hawaiians or Asian Natives. TTN mutation frequency was lower in Asian patients. With regards to mutation frequencies at different tumor stages, in all genes, >50% of the mutations occurred during the first stage, except in TP53 and POLQ. In terms of prognosis in endometrial cancer considering the 10 most frequently mutated genes, PIK3CA and ARID1A mutations were correlated with good prognosis, whereas TP53 and PIK3R1 mutations were correlated with poor prognosis; mutations in all other genes did not show significant differences. Conclusion: This study revealed a new mutation frequency profile for different ethnicities and tumor grades in endometrial cancer patients. However, because this is a retrospective study, future prospective studies should be conducted including large sample sizes and more controlled measurements

Development of Transdermal Oleogel Containing Olmesartan Medoxomil: Statistical Optimization and Pharmacological Evaluation

Olmesartan medoxomil (OLM) is a first-line antihypertensive drug with low oral bioavailability (28.6%). This study aimed to develop oleogel formulations to decrease OLM side effects and boost its therapeutic efficacy and bioavailability. OLM oleogel formulations were composed of Tween 20, Aerosil 200, and lavender oil. A central composite response surface design chose the optimized formulation, containing Oil/Surfactant (SAA) ratio of 1:1 and Aerosil % of 10.55%, after showing the lowest firmness and compressibility, and the highest viscosity, adhesiveness, and bioadhesive properties (Fmax and Wad). The optimized oleogel increased OLM release by 4.21 and 4.97 folds than the drug suspension and gel, respectively. The optimized oleogel formulation increased OLM permeation by 5.62 and 7.23 folds than the drug suspension and gel, respectively. The pharmacodynamic study revealed the superiority of the optimized formulation in maintaining normal blood pressure and heart rate for 24 h. The biochemical analysis revealed that the optimized oleogel achieved the best serum electrolyte balance profile, preventing OLM-induced tachycardia. The pharmacokinetic study showed that the optimized oleogel increased OLM’s bioavailability by more than 4.5- and 2.5-folds compared to the standard gel and the oral market tablet, respectively. These results confirmed the success of oleogel formulations in the transdermal delivery of OLM

BTK blocks the inhibitory effects of MDM2 on p53 activity

p53 is a tumour suppressor that is activated in response to various types of stress. It is regulated by a complex pattern of over 50 different post-translational modifications, including ubiquitination by the E3 ligase MDM2, which leads to its proteasomal degradation. We have previously reported that expression of Bruton's Tyrosine Kinase (BTK) induces phosphorylation of p53 at the N-terminus, including Serine 15, and increases its protein levels and activity. The mechanisms involved in this process are not completely understood. Here, we show that BTK also increases MDM2 and is necessary for MDM2 upregulation after DNA damage, consistent with what we have shown for other p53 target genes. Moreover, we found that BTK binds to MDM2 on its PH domain and induces its phosphorylation. This suggested a negative regulation of MDM2 functions by BTK, supported by the fact BTK expression rescued the inhibitory effects of MDM2 on p53 transcriptional activity. Indeed, we observed that BTK mediated the loss of the ubiquitination activity of MDM2, a process that was dependent on the phosphorylation functions of BTK. Our data together shows that the kinase activity of BTK plays an important role in disrupting the MDM2-p53 negative feedback loop by acting at different levels, including binding to and inactivation of MDM2. This study provides a potential mechanism to explain how BTK modulates p53 functions

In Vivo and In Vitro Enhanced Tumoricidal Effects of Metformin, Active Vitamin D3, and 5-Fluorouracil Triple Therapy against Colon Cancer by Modulating the PI3K/Akt/PTEN/mTOR Network

Chemoresistance to 5-fluorouracil (5-FU) is common during colorectal cancer (CRC) treatment. This study measured the chemotherapeutic effects of 5-FU, active vitamin D3 (VD3), and/or metformin single/dual/triple regimens as complementary/alternative therapies. Ninety male mice were divided into: negative and positive (PC) controls, and 5-FU, VD3, Met, 5-FU/VD3, 5-FU/Met, VD3/Met, and 5-FU/VD3/Met groups. Treatments lasted four weeks following CRC induction by azoxymethane. Similar regimens were also applied in the SW480 and SW620 CRC cell lines. The PC mice had abundant tumours, markedly elevated proliferation markers (survivin/CCND1) and PI3K/Akt/mTOR, and reduced p21/PTEN/cytochrome C/caspase-3 and apoptosis. All therapies reduced tumour numbers, with 5-FU/VD3/Met being the most efficacious regimen. All protocols decreased cell proliferation markers, inhibited PI3K/Akt/mTOR molecules, and increased proapoptotic molecules with an apoptosis index, and 5-FU/VD3/Met revealed the strongest effects. In vitro, all therapies equally induced G1 phase arrest in SW480 cells, whereas metformin-alone showed maximal SW620 cell numbers in the G0/G1 phase. 5-FU/Met co-therapy also showed the highest apoptotic SW480 cell numbers (13%), whilst 5-FU/VD3/Met disclosed the lowest viable SW620 cell percentages (81%). Moreover, 5-FU/VD3/Met revealed maximal inhibitions of cell cycle inducers (CCND1/CCND3), cell survival (BCL2), and the PI3K/Akt/mTOR molecules alongside the highest expression of cell cycle inhibitors (p21/p27), proapoptotic markers (BAX/cytochrome C/caspase-3), and PTEN in both cell lines. In conclusion, metformin monotherapy was superior to VD3, whereas the 5-FU/Met protocol showed better anticancer effects relative to the other dual therapies. However, the 5-FU/VD3/Met approach displayed the best in vivo and in vitro tumoricidal effects related to cell cycle arrest and apoptosis, justifiably by enhanced modulations of the PI3K/PTEN/Akt/mTOR pathway

Doxorubicin-sanguinarine nanoparticles: formulation and evaluation of breast cancer cell apoptosis and cell cycle

Therapeutic resistance fails cancer treatment. Drug-nanoparticle combinations overcome resistance. Sanguinarine-conjugated nanoparticles may boost sanguinarine’s anticancer effects. Sanguinarine, HPMC-NPs, and doxorubicin were tested on Adriamycin-resistant MCF-7/ADR breast cancer cells, parent-sensitive MCF-7, and MCR-5 normal cells (DX). Regular distribution, 156 nm diameter, 50 = 1.4 μM) more than MCF-7/ADR cells (IC50 = 27 μM) with RR = 19.3. SA and SN were more toxic to MCF-7/ADR cells (overexpressed with P-gp) than their sensitive parent MCF-7 cells (IC50 = 4 μM, RR = 0.6 and 0.6 μM, RR = 0.7). MCR-5 normal lung cells were more resistant to SA (IC50 = 7.2 μM) and SN (IC50 = 1.6 μM) with a selection index > 2. Synergistic cytotoxic interactions reduced the IC50 from 27 μM to 1.6 (CI = 0.1) and 0.9 (CI = 0.4) after DX and nontoxic dosages (IC20) of SA and SN. DS and SN killed 27.1% and 39.4% more cells than DX (7.7%), SA (4.9%), SN (5.5%), or untreated control (0.3%). DS and DSN lowered CCND1 and survival in MCF-7/ADR cells while raising p21 and Casp3 gene and protein expression. Cellular and molecular studies suggested adjuvant chemosensitizers SA and SN to reverse MDR in breast cancer cells.</p