Effectiveness of EGFR/HER2-targeted drugs is influenced by the downstream interaction shifts of PTPIP51 in HER2-amplified breast cancer cells

Mubritinib enhanced the inhibiting function of cisplatin in lung cancer by interfering with mitochondrial function

Background

Lung cancer is one of the most lethal cancers worldwide. Cisplatin, a widely used anti‐lung cancer drug, has been limited in clinical application due to its drug resistance. Medicines targeting mitochondrial electron transport chain (ETC) complexes may be effective candidates for cisplatin‐based chemotherapy.

Methods

In this study, the small molecule drug library from Food and Drug Administration FDA was used to screen for medicines targeting ETC. MTT and colony formation assays were used to investigate cell proliferation. Flow cytometry was employed to analyze cell cycle, apoptosis, reactive oxygen species (ROS), and mitochondrial membrane potential. Wound scratch and transwell assays were used to detect migration and invasion abilities. The activities of the ETC complex were tested using kits. Western blot analysis was used to investigate the expressions of related proteins. A mouse xenograft model was constructed to verify the antitumor effect in vivo.

Results

The results showed that mubritinib can reduce the activation of the PI3K/mTOR signal pathway, disrupt mitochondrial function, significantly increase ROS levels and induce oxidative stress, and ultimately exert its antitumor effect against non‐small cell lung cancer (NSCLC) both in vivo and in vitro. In addition, the combination of cisplatin and mubritinib can improve the tumor‐suppressive effect of cisplatin.

Conclusion

Mubritinib can upregulate intracellular ROS concentration and cell apoptosis, inhibit the PI3K signaling pathway and interfere with the function of mitochondria, thus reducing cell proliferation and increasing ROS induced apoptosis by reducing the activation of Nrf2 by PI3K.

Molecular Targeting of Epidermal Growth Factor Receptor (EGFR) and Vascular Endothelial Growth Factor Receptor (VEGFR)

Epidermal growth factor receptor (EGFR) and vascular endothelial growth factor receptor (VEGFR) are two extensively studied membrane-bound receptor tyrosine kinase proteins that are frequently overexpressed in many cancers. As a result, these receptor families constitute attractive targets for imaging and therapeutic applications in the detection and treatment of cancer. This review explores the dynamic structure and structure-function relationships of these two growth factor receptors and their significance as it relates to theranostics of cancer, followed by some of the common inhibition modalities frequently employed to target EGFR and VEGFR, such as tyrosine kinase inhibitors (TKIs), antibodies, nanobodies, and peptides. A summary of the recent advances in molecular imaging techniques, including positron emission tomography (PET), single-photon emission computerized tomography (SPECT), computed tomography (CT), magnetic resonance imaging (MRI), and optical imaging (OI), and in particular, near-IR fluorescence imaging using tetrapyrrolic-based fluorophores, concludes this review.

A comprehensive review on the role of protein tyrosine phosphatases in gastric cancer development and progression

The main post-translational reversible modulation of proteins is phosphorylation and dephosphorylation, catalyzed by protein kinases (PKs) and protein phosphatases (PPs) which is crucial for homeostasis. Imbalance in this crosstalk can be related to diseases, including cancer. Plenty of evidence indicates that protein tyrosine phosphatases (PTPs) can act as tumor suppressors and tumor promoters. In gastric cancer (GC), there is a lack of understanding of the molecular aspects behind the tumoral onset and progression. Here we describe several members of the PTP family related to gastric carcinogenesis. We discuss the associated molecular mechanisms which support the down or up modulation of different PTPs. We emphasize the Helicobacter pylori (H. pylori) virulence which is in part associated with the activation of PTP receptors. We also explore the involvement of intracellular redox state in response to H. pylori infection. In addition, some PTP members are under influence by genetic mutations, epigenetics mechanisms, and miRNA modulation. The understanding of multiple aspects of PTPs in GC may provide new targets and perspectives on drug development.

PTPIP51 crosslinks the NFκB signaling and the MAPK pathway in SKBR3 cells

Aim:

PTPIP51 interacts with NFκB signaling at the RelA and IκB level. NFκB signaling is linked to the initiation, progression and metastasis of breast cancer. Her2-amplified breast cancer cells frequently display activation of the NFκB signaling. We aimed to clarify the effects of NFκB inhibition on the NFκB- and MAPK-related interactome of PTPIP51 and cell viability in HaCat cells and SKBR3 cells.

Results:

IKK-16 selectively reduced cell viability in SKBR3 cells. PDTC induced a formation of the Raf1/14-3-3/PTPIP51 complex in SKBR3 cells, indicating a shift of PTPIP51 into MAPK signaling.

Conclusion:

IKK-16 selectively inhibits cell viability of SKBR3 cells. In addition, PTPIP51 might serve as the mediator between NFκB signaling and the MAPK pathway in SKBR3.

Breast cancer is the most common cancerous disease among women. Prognosis and therapy of breast cancer depends on the expression of hormone and surface receptors such as Her2, which promote tumor growth and invasion via activation of downstream signaling pathways. NFκB signaling represents a downstream signaling pathway that can be activated by Her2. In this study, we demonstrated that inhibition of NFκB signaling with IKK-16 reduces cell viability in breast cancer cells with amplified Her2. Furthermore, we identified PTPIP51 as a potential mediator of crosstalks between the MAPK pathway and NFκB signaling. This signaling pathway could therefore be a target for future drug development.

The Importance of the Right Framework: Mitogen-Activated Protein Kinase Pathway and the Scaffolding Protein PTPIP51

The protein tyrosine phosphatase interacting protein 51 (PTPIP51) regulates and interconnects signaling pathways, such as the mitogen-activated protein kinase (MAPK) pathway and an abundance of different others, e.g., Akt signaling, NF-κB signaling, and the communication between different cell organelles. PTPIP51 acts as a scaffold protein for signaling proteins, e.g., Raf-1, epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (Her2), as well as for other scaffold proteins, e.g., 14-3-3 proteins. These interactions are governed by the phosphorylation of serine and tyrosine residues of PTPIP51. The phosphorylation status is finely tuned by receptor tyrosine kinases (EGFR, Her2), non-receptor tyrosine kinases (c-Src) and the phosphatase protein tyrosine phosphatase 1B (PTP1B). This review addresses various diseases which display at least one alteration in these enzymes regulating PTPIP51-interactions. The objective of this review is to summarize the knowledge of the MAPK-related interactome of PTPIP51 for several tumor entities and metabolic disorders.