Molecular dynamics-based identification of novel natural mortalin-p53 abrogators as anticancer agents

Synthetic and Natural Inhibitors of Mortalin for Cancer Therapy

Upregulation of stress chaperone Mortalin has been closely linked to the malignant transformation of cells, tumorigenesis, the progression of tumors to highly aggressive stages, metastasis, drug resistance, and relapse. Various in vitro and in vivo assays have provided evidence of the critical role of Mortalin upregulation in promoting cancer cell characteristics, including proliferation, migration, invasion, and the inhibition of apoptosis, a consistent feature of most cancers. Given its critical role in several steps in oncogenesis and multi-modes of action, Mortalin presents a promising target for cancer therapy. Consequently, Mortalin inhibitors are emerging as potential anti-cancer drugs. In this review, we discuss various inhibitors of Mortalin (peptides, small RNAs, natural and synthetic compounds, and antibodies), elucidating their anti-cancer potentials.

Heat shock proteins as hallmarks of cancer: insights from molecular mechanisms to therapeutic strategies

Heat shock proteins are essential molecular chaperones that play crucial roles in stabilizing protein structures, facilitating the repair or degradation of damaged proteins, and maintaining proteostasis and cellular functions. Extensive research has demonstrated that heat shock proteins are highly expressed in cancers and closely associated with tumorigenesis and progression. The "Hallmarks of Cancer" are the core features of cancer biology that collectively define a series of functional characteristics acquired by cells as they transition from a normal state to a state of tumor growth, including sustained proliferative signaling, evasion of growth suppressors, resistance to cell death, enabled replicative immortality, the induction of angiogenesis, and the activation of invasion and metastasis. The pivotal roles of heat shock proteins in modulating the hallmarks of cancer through the activation or inhibition of various signaling pathways has been well documented. Therefore, this review provides an overview of the roles of heat shock proteins in vital biological processes from the perspective of the hallmarks of cancer and summarizes the small-molecule inhibitors that target heat shock proteins to regulate various cancer hallmarks. Moreover, we further discuss combination therapy strategies involving heat shock proteins and promising dual-target inhibitors to highlight the potential of targeting heat shock proteins for cancer treatment. In summary, this review highlights how targeting heat shock proteins could regulate the hallmarks of cancer, which will provide valuable information to better elucidate and understand the roles of heat shock proteins in oncology and the mechanisms of cancer occurrence and development and aid in the development of more efficacious and less toxic novel anticancer agents.

Pharmacoinformatics approach for the screening of Kovidra (Bauhinia variegata) phytoconstituents against tumor suppressor protein in triple negative breast cancer

Globally, 2.3 million women were diagnosed with breast cancer, with 6,85000 mortalities in year 2021; making it the world's most prevalent cancer. This growing global burden necessitates a new treatment option, and plant-based medicines offers a promising alternative to conventional cancer treatment. In this work, screening of phytoconstituents of an indigenous therapeutic plant, Bauhinia variegata carried out for potential regulator of tumor suppressor protein p53. Here, an in-silico analysis was employed to develop more effective, pharmaceutically potent small drug-like compounds that target tumor suppressor protein p53. The methanol and aqueous powdered extracts of Bauhinia variegata were prepared and phytochemically evaluated along with antioxidant property evaluation. The LC50 of methanol (325.33 µg/ml) and aqueous extract (361.15 µg/ml) showed their cytotoxic characteristics. Further, GCMS analysis of both the extracts reveals total 57 secondary metabolites. Among these, four lead compounds; compound 1, compound 2, compound 3 and compound 4 were found to have the highest binding ability (-8.15 to -5.40 kcal/mol) with p53. MD simulation and binding free energy validates these findings with highest binding free energy (-67.09 ± 4.87 kcal/mol) towards p53 by the lead phytocompound 2. Selected compounds exhibit excellent pharmacokinetic features and drug-like characteristics. The acute toxicity (LD50) values of the lead phytocompounds ranges from 670 mg/kg to 3100 mg/kg, with toxicity classes of IV and V. As a result, these druggable phytochemicals could serve as potential lead applicants for triple negative breast cancer treatment. However, more in vitro and in vivo research is planned to produce future breast cancer medicine. HIGHLIGHTSScreening of phytoconstituents of an indigenous therapeutic plant, Bauhinia variegata, for potential regulator of tumor suppressor protein p53.The LC50 of methanol (325.33µg/ml) and aqueous extract (361.15µg/ml) showed their cytotoxic characteristics.GCMS analysis of both the extracts reveals total 57 secondary metabolites. Among these, four lead compounds were found to have the highest binding affinity (-8.153 to -5.401 kcal/mol) with tumor suppressor protein p53.MD simulation along with the Prime MM/GBSA binding free energy validates this discovery with highest binding free energy (-67.09 ± 4.87 kcal/mol) towards p53 by the lead compound 2.The acute toxicity (LD50) values of the lead phytocompounds ranges from 670 mg/kg to 3100 mg/kg, with toxicity classes of IV and V.As a result, these druggable phytochemicals could serve as potential lead applicants for triple negative breast cancer treatment.Communicated by Ramaswamy H. Sarma.

Restoration of p53 functions by suppression of mortalin-p53 sequestration: an emerging target in cancer therapy

Functional inactivation of wild-type p53 is a major trait of cancerous cells. In many cases, such inactivation occurs by either TP53 gene mutations or due to overexpression of p53 binding partners. This review focuses on an overexpressed p53 binding partner called mortalin, a mitochondrial heat shock protein that sequesters both wild-type and mutant p53 in malignant cells due to changes in subcellular localization. Clinical evidence suggests a drastic depletion of the overall survival time of cancer patients with high mortalin expression. Therefore, mortalin-p53 sequestration inhibitors could be game changers in improving overall survival rates. This review explores the consequences of mortalin overexpression and challenges, status and strategies for accelerating drug discovery to suppress mortalin-p53 sequestration.

Abrogating the Interaction Between p53 and Mortalin (Grp75/HSPA9/mtHsp70) for Cancer Therapy: The Story so far

p53 is a transcription factor that activates the expression of a set of genes that serve as a critical barrier to oncogenesis. Inactivation of p53 is the most common characteristic in sporadic human cancers. Mortalin is a differentially sub-cellularly localized member of the heat shock protein 70 family of chaperones that has essential mitochondrial and extra-mitochondrial functions. Elevated mortalin levels in multiple cancerous tissues and tumor-derived cell lines emphasized its key role in oncogenesis. One of mortalin’s major oncogenic roles is the inactivation of p53. Mortalin binds to p53 sequestering it in the cytoplasm. Hence, p53 cannot freely shuttle to the nucleus to perform its tumor suppressor functions as a transcription factor. This protein-protein interaction was reported to be cancer-specific, hence, a selective druggable target for a rationalistic cancer therapeutic strategy. In this review article, the chronological identification of mortalin-p53 interactions is summarized, the challenges and general strategies for targeting protein-protein interactions are briefly discussed, and information about compounds that have been reported to abrogate mortalin-p53 interaction is provided. Finally, the reasons why the disruption of this druggable interaction has not yet been applied clinically are discussed.

Salvianolic acid B targets mortalin and inhibits the migration and invasion of hepatocellular carcinoma via the RECK/STAT3 pathway

BACKGROUND

Tumor migration and invasion is a complex and diverse process that involves the epithelial-mesenchymal transition (EMT) of tumor cells and degradation of the extracellular matrix by matrix metalloproteases (MMPs). Mortalin is an important oncogene. It has been reported to play an important role in tumor migration and invasion through various signaling pathways, but the underlying mechanism is not fully understood.

METHODS

Here, we investigated the role of mortalin in the migration of the hepatocellular carcinoma (HCC) cell lines HepG2 and HCCLM3.

RESULTS

The overexpression of mortalin in HepG2 cells decreased the protein level of reversion-inducing cysteine-rich protein with Kazal motifs (RECK) and activated the phosphorylation and acetylation of STAT3, thereby up-regulating matrix metalloproteinase 9 (MMP9) and promoting cell migration and invasion. In contrast, in HCCLM3 cells, mortalin knockdown increased the expression of RECK, inhibited the STAT3 pathway and the activity of MMP9, and inhibited cell migration and invasion. Furthermore, we found that salvianolic acid B, a caffeic acid phenethyl ester analog, specifically bound to mortalin and increased the degradation of mortalin proteasomes through ubiquitination, thereby up-regulating RECK, inhibiting STAT3, and finally inhibiting the migration and invasion of HCC cells.

CONCLUSION

Our work suggested that mortalin is a potential therapeutic target for hepatocellular carcinoma.

Structural investigations on mechanism of lapatinib resistance caused by HER-2 mutants

HER-2 belongs to the human epidermal growth factor receptor (HER) family. Via different signal transduction pathways, HER-2 regulates normal cell proliferation, survival, and differentiation. Recently, it was reported that MCF10A, BT474, and MDA-MB-231 cells bearing the HER2 K753E mutation were resistant to lapatinib. Present study revealed that HER-2 mutant K753E showed some contrasting behaviour as compared to wild, L768S and V773L HER-2 in complex with lapatinib while similar to previously known lapatinib resistant L755S HER-2 mutant. Lapatinib showed stable but reverse orientation in binding site of K753E and the highest binding energy among studied HER2-lapatinib complexes but slightly lesser than L755S mutant. Results indicate that K753E has similar profile as L755S mutant for lapatinib. The interacting residues were also found different from other three studied forms as revealed by free energy decomposition and ligplot analysis.