The effect of Phyllanthus niruri L extracts on human leukemic cell proliferation and apoptosis induction

Objective: To investigate the effect of Phyllanthus niruri Linn (Euphorbiaceae) in the proliferation of human leukemic cells (MOLT-4 and K562).Methods: Phyllanthus niruri L (P.niruri) was macerated by using various solvents to obtain the crude extracts. Cytotoxicity of the extracts against MOLT-4 and K562 cells was tested using MTT assay to find the IC50 value. To analyse cell cycle progression, cellular DNA was measured using propidium iodide (PI) staining. Apoptosis induction was evaluated using Annexin V-FITC and PI staining and analysed using FACSVerse flow cytometry. Finally, the expression of p53 on MOLT-4 and K562 cell lysate was measured by western blotting, to identify the possible mode of action of the anticancer activity.Results: P. niruri crude extracts demonstrated a potential anti-cancer effect towards MOLT-4 cells (IC50 range was 42.21 ± 4.98 to 97.06 ± 18.29 µg/ml). However, against K562 cells, P.niruri extracts exhibited a lower inhibitory potency (the IC50 was 120.19 ± 8.48 to 256.55 ± 26.22 µg/ml). The results showed the selectivity of the toxic effect of the extracts against MOLT-4 and K562.  To evaluate the possible mechanism of action the anticancer effect, we evaluated P. niruri extract action in apoptosis induction and p53 expression. The results showed that methanol and hexane extract inhibited MOLT-4 cell progression from G1 to S-phase, indicating G1 cell arrest. Moreover, apoptotic cell population following treatment of MOLT-4 and K562 cells with methanol extract was markedly increased, showing morphological signs of apoptosis including membrane degradation and chromatin condensation. Furthermore, we found that there was an increase in p53 expression following MOLT-4 treatment with methanol extract, suggesting that p53 induction may be involved in cell apoptosis.Conclusions: The results indicated the involvement of p53 pathway in the mechanism of anti-cancer activity exerted by P. niruri extract on MOLT-4 cells. However, for cancer cells lacking P53 expression, such as K562 cells, apoptosis might take place via other pathways

Evaluation of the Role of p53 Tumour Suppressor Posttranslational Modifications and TTC5 Cofactor in Lung Cancer

From MDPI via Jisc Publications RouterHistory: accepted 2021-12-02, pub-electronic 2021-12-07Publication status: PublishedFunder: This research was funded by the Rosemere Cancer Foundation, Hasen Alhebshi was funded by the Libyan government.; Grant(s): No grant number available.Mutations in the p53 tumor suppressor are found in over 50% of cancers. p53 function is controlled through posttranslational modifications and cofactor interactions. In this study, we investigated the posttranslationally modified p53, including p53 acetylated at lysine 382 (K382), p53 phosphorylated at serine 46 (S46), and the p53 cofactor TTC5/STRAP (Tetratricopeptide repeat domain 5/ Stress-responsive activator of p300-TTC5) proteins in lung cancer. Immunohistochemical (IHC) analysis of lung cancer tissues from 250 patients was carried out and the results were correlated with clinicopathological features. Significant associations between total or modified p53 with a higher grade of the tumour and shorter overall survival (OS) probability were detected, suggesting that mutant and/or modified p53 acts as an oncoprotein in these patients. Acetylated at K382 p53 was predominantly nuclear in some samples and cytoplasmic in others. The localization of the K382 acetylated p53 was significantly associated with the gender and grade of the disease. The TTC5 protein levels were significantly associated with the grade, tumor size, and node involvement in a complex manner. SIRT1 expression was evaluated in 50 lung cancer patients and significant positive correlation was found with p53 S46 intensity, whereas negative TTC5 staining was associated with SIRT1 expression. Furthermore, p53 protein levels showed positive association with poor OS, whereas TTC5 protein levels showed positive association with better OS outcome. Overall, our results indicate that an analysis of p53 modified versions together with TTC5 expression, upon testing on a larger sample size of patients, could serve as useful prognostic factors or drug targets for lung cancer treatment

p53 modeling as a route to mesothelioma patients stratification and novel therapeutic identification

Background Malignant pleural mesothelioma (MPM) is an orphan disease that is difficult to treat using traditional chemotherapy, an approach which has been effective in other types of cancer. Most chemotherapeutics cause DNA damage leading to cell death. Recent discoveries have highlighted a potential role for the p53 tumor suppressor in this disease. Given the pivotal role of p53 in the DNA damage response, here we investigated the predictive power of the p53 interactome model for MPM patients’ stratification. Methods We used bioinformatics approaches including omics type analysis of data from MPM cells and from MPM patients in order to predict which pathways are crucial for patients’ survival. Analysis of the PKT206 model of the p53 network was validated by microarrays from the Mero-14 MPM cell line and RNA-seq data from 71 MPM patients, whilst statistical analysis was used to identify the deregulated pathways and predict therapeutic schemes by linking the affected pathway with the patients’ clinical state. Results In silico simulations demonstrated successful predictions ranging from 52 to 85% depending on the drug, algorithm or sample used for validation. Clinical outcomes of individual patients stratified in three groups and simulation comparisons identified 30 genes that correlated with survival. In patients carrying wild-type p53 either treated or not treated with chemotherapy, FEN1 and MMP2 exhibited the highest inverse correlation, whereas in untreated patients bearing mutated p53, SIAH1 negatively correlated with survival. Numerous repositioned and experimental drugs targeting FEN1 and MMP2 were identified and selected drugs tested. Epinephrine and myricetin, which target FEN1, have shown cytotoxic effect on Mero-14 cells whereas marimastat and batimastat, which target MMP2 demonstrated a modest but significant inhibitory effect on MPM cell migration. Finally, 8 genes displayed correlation with disease stage, which may have diagnostic implications. Conclusions Clinical decisions related to MPM personalized therapy based on individual patients’ genetic profile and previous chemotherapeutic treatment could be reached using computational tools and the predictions reported in this study upon further testing in animal models

Evaluation of the role of p53 tumor suppressor post-translational modifications and TTC5 cofactor in lung cancer

Mutations in the p53 tumor suppressor are found in over 50% of cancers. p53 function is controlled through posttranslational modifications and cofactor interactions. In this study, we investigated the posttranslationally modified p53, including p53 acetylated at lysine 382 (K382), p53 phosphorylated at serine 46 (S46), and the p53 cofactor TTC5/STRAP (Tetratricopeptide repeat domain 5/ Stress-responsive activator of p300-TTC5) proteins in lung cancer. Immunohistochemical (IHC) analysis of lung cancer tissues from 250 patients was carried out and the results were correlated with clinicopathological features. Significant associations between total or modified p53 with a higher grade of the tumour and shorter overall survival (OS) probability were detected, suggesting that mutant and/or modified p53 acts as an oncoprotein in these patients. Acetylated at K382 p53 was predominantly nuclear in some samples and cytoplasmic in others. The localization of the K382 acetylated p53 was significantly associated with the gender and grade of the disease. The TTC5 protein levels were significantly associated with the grade, tumor size, and node involvement in a complex manner. SIRT1 expression was evaluated in 50 lung cancer patients and significant positive correlation was found with p53 S46 intensity, whereas negative TTC5 staining was associated with SIRT1 expression. Furthermore, p53 protein levels showed positive association with poor OS, whereas TTC5 protein levels showed positive association with better OS outcome. Overall, our results indicate that an analysis of p53 modified versions together with TTC5 expression, upon testing on a larger sample size of patients, could serve as useful prognostic factors or drug targets for lung cancer treatment