Carbon Nanotube-Mediated Delivery of PTEN Variants: In Vitro Antitumor Activity in Breast Cancer Cells.

Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is a crucial tumor suppressor protein with frequent mutations and alterations. Although protein therapeutics are already integral to numerous medical fields, their potential remains nascent. This study aimed to investigate the impact of stable, unphosphorylated recombinant human full-length PTEN and its truncated variants, regarding their tumor suppression activity with multiwalled-carbon nanotubes (MW-CNTs) as vehicles for their delivery in breast cancer cells (T-47D, ZR-75-1, and MCF-7). The cloning, overexpression, and purification of PTEN variants were achieved from E. coli, followed by successful binding to CNTs. Cell incubation with protein-functionalized CNTs revealed that the full-length PTEN-CNTs significantly inhibited cancer cell growth and stimulated apoptosis in ZR-75-1 and MCF-7 cells, while truncated PTEN fragments on CNTs had a lesser effect. The N-terminal fragment, despite possessing the active site, did not have the same effect as the full length PTEN, emphasizing the necessity of interaction with the C2 domain in the C-terminal tail. Our findings highlight the efficacy of full-length PTEN in inhibiting cancer growth and inducing apoptosis through the alteration of the expression levels of key apoptotic markers. In addition, the utilization of carbon nanotubes as a potent PTEN protein delivery system provides valuable insights for future applications in in vivo models and clinical studies.

Recent advances in targeting protein kinases and pseudokinases in cancer biology.

Kinases still remain the most favorable members of the druggable genome, and there are an increasing number of kinase inhibitors approved by the FDA to treat a variety of cancers. Here, we summarize recent developments in targeting kinases and pseudokinases with some examples. Targeting the cell cycle machinery garnered significant clinical success, however, a large section of the kinome remains understudied. We also review recent developments in the understanding of pseudokinases and discuss approaches on how to effectively target in cancer.

Multiwalled Carbon Nanotubes for Dental Applications.

Multiwalled carbon nanotubes (MWCNTs) are a particularly promising drug delivery system due to their high surface area allowing high-protein loading, their stability under biological conditions, and their unique interaction with cellular membranes. Studies have shown that covalent attachment of polyethylene glycol (PEG) improves biocompatibility and enhances surface hydrophilicity properties, suggesting that PEGylated MWCNTs are efficient and toxic-safe drug delivery systems. So far, CNTs are used for a broad range of applications in dentistry, especially for dental tissue repair and restorative. Here we present a protocol of protein immobilization onto MWCNTs and describe the procedure for delivering them into the cells after characterization of the nanotubes.

The Synthesis of 1,3,5-triazine Derivatives and JNJ7777120 Analogues with Histamine H4 Receptor Affinity and Their Interaction with PTEN Promoter.

The involvement of histamine and H4 receptor (H4 R) in cancer has been investigated recently using the H4 R agonists and antagonists. The scope of the research project was synthesis and exploration of the consequences of a group of compounds with histamine H4 receptor (H4 R) affinity on the promoter of PTEN gene encoding the antitumor PTEN protein. The series of novel compounds based either on H4 R antagonists JNJ7777120 structure or 1,3,5-triazine scaffold were synthesized, evaluated for histamine H4 R affinity and used in this study. Compounds 5 and 7 belonging to the group of JNJ7777120 analogues showed the highest interaction with the promoter of PTEN gene and weak affinity against H4 R with Ki value >100 µm. These compounds showed no significant effect on neuroblastoma IMR-32 cells viability indicating no correlation between PTEN gene promoter affinity and antitumor activity. Compound 6, another JNJ7777120 analogue, showed the highest effect on IMR-32 viability with calculated IC50 = 23.27 µm. The 1,3,5-triazine derivatives exhibited generally low or medium interaction with PTEN gene promoter. However, the 1,3,5-triazine derivative 11 with the para-bromo substituent showed the highest affinity against H4 R with Ki value of 520 nm and may be considered as a new lead structure.

Tumor suppressor PTEN in breast cancer: heterozygosity, mutations and protein expression.

Phosphatase and tensin homolog deleted on chromosome ten (PTEN) is one of the most frequently mutated human tumor suppressor genes, implicated in cell growth and survival and suppressing tumor formation. Loss of PTEN activity, either at the protein or genomic level, has been related to many primary and metastatic malignancies including breast cancer. The present study investigates the heterozygosity, mutation spectrum and protein expression of PTEN in 43 patients with breast cancer or precursor lesions of the breast and 10 healthy individuals. Microsatellite analysis at the PTEN locus using D10S215, D10S541 and D10S579 markers indicated that the observed heterozygosity (Ho) is lower than the expected heterozygosity (Hs) in benign and malignant breast disease. Mutational analysis in exons 1, 5, 7 and 9 of the PTEN gene revealed several mutations, most of which cause truncation of the PTEN protein and consequently loss of activity. Increased circulating levels of PTEN and phosphorylated PTEN protein were also observed by immunostaining in patients with breast cancer and precursor breast lesions. In support, increased PTEN protein expression was detected in corresponding tissue specimens. Our data suggest an association between breast cancer and PTEN mutations, resulting in the production of truncated forms of the corresponding protein, thus indicating that breast carcinogenesis is potentially related to PTEN loss of activity rather than loss of expression. Peripheral blood sampling may provide an advantageous application for the determination of PTEN gene mutations and its protein expression in human cancer.