Withanolide D Enhances Radiosensitivity of Human Cancer Cells by Inhibiting DNA Damage Non-homologous End Joining Repair Pathway

LncRNA TMPO-AS1 Promotes Triple-Negative Breast Cancer by Sponging miR-383-5p to Trigger the LDHA Axis

BACKGROUND

Understanding the heterogeneous nature of breast cancer, including the role of LDHA expression regulation via non-coding RNAs in prognosis, is still unknown, highlighting the need for more research into its molecular roles and diagnostic approaches.

METHODS

The study utilized various computer tools to analyze the differences between LDHA in tissues and cancer cells. It used data from TIMER 2.0, UALCAN, and TISIDB to study gene expression and survival outcomes in breast cancer patients. The study also used the Breast Cancer Gene Expression Miner to examine the relationship between LDHA gene expression and breast cancer type. Other tools included TCGAPortal, TNMplot, ctcRbase, GSCA, Enrichr, TISIDB, Oncomx, and TANRIC. The study then explored the relationship between tumor-infiltrating immune cells and LDHA formation using the GSCA and TISIDB repositories. We used Auto Dock Tools 1.5.6 to perform ligand binding analysis for LDHA, withanolides, and the known inhibitor LDH-IN-1. LigPlot+ and Pymol were used for visualization of protein-ligand complexes.

RESULTS

LDHA overexpression in breast cancer cells, metastatic tissue, and circulating tumor cells leads to shortened recurrence-free survival, overall survival, and distant metastasis-free survival. In invasive breast cell carcinoma, we observed that LDHA/HIF-1α /TMPO-AS1 are overexpressed while miR-383-5p is downregulated. This overexpression is associated with poor prognosis and may lead to Act_DC infiltration into the tumor microenvironment. Withanolides, viz., Withaferine A and Withanolide D, have shown high binding affinity with LDHA, with binding energies of -9.3kcal/mol and -10kcal/mol respectively. These could be attractive choices for small-molecule inhibitor design against LDHA.

Withanolides: Promising candidates for cancer therapy

Natural products have played a significant role throughout history in the prevention and treatment of numerous diseases, particularly cancers. As a natural product primarily derived from various medicinal plants in the Withania genus, withanolides have been shown in several studies to exhibit potential activities in cancer treatment. Consequently, understanding the molecular mechanism of withanolides could herald the discovery of new anticancer agents. Withanolides have been studied widely, especially in the last 20 years, and attracted the attention of numerous researchers. Currently, over 1200 withanolides have been classified, with approximately a quarter of them having been reported in the literature to be able to modulate the survival and death of cancer cells through multiple avenues. To what extent, though, has the anticancer effects of these compounds been studied? How far are they from being developed into clinical drugs? What are their potential, characteristic features, and challenges? In this review, we elaborate on the current knowledge of natural compounds belonging to this class and provide an overview of their natural sources, anticancer activity, mechanism of action, molecular targets, and implications for anticancer drug research. In addition, direct targets and clinical research to guide the design and implementation of future preclinical and clinical studies to accelerate the application of withanolides have been highlighted.

Natural products as chemo-radiation therapy sensitizers in cancers

Cancer is a devastating disease and is the second leading cause of death worldwide. Surgery, chemotherapy (CT), and/or radiation therapy (RT) are the treatment of choice for most advanced tumors. Unfortunately, treatment failure due to intrinsic and acquired resistance to the current CT and RT is a significant challenge associated with poor patient prognosis. There is an urgent need to develop and identify agents that can sensitize tumor cells to chemo-radiation therapy (CRT) with minimal cytotoxicity to the healthy tissues. While many recent studies have identified the underlying molecular mechanisms and therapeutic targets for CRT failure, using small molecule inhibitors to chemo/radio sensitize tumors is associated with high toxicity and increased morbidity. Natural products have long been used as chemopreventive agents in many cancers. Combining many of these compounds with the standard chemotherapeutic agents or with RT has shown synergistic effects on cancer cell death and overall improvement in patient survival. Based on the available data, there is strong evidence that natural products have a robust therapeutic potential along with CRT and their well-known chemopreventive effects in many solid tumors. This review article reports updated literature on different natural products used as CT or RT sensitizers in many solid tumors. This is the first review discussing CT and RT sensitizers together in cancer.

Natural withanolides, an update

Covering: March 2010 to December 2020. Previous review: Nat. Prod. Rep., 2011, 28, 705This review summarizes the latest progress and perspectives on the structural classification, biological activities and mechanisms, metabolism and pharmacokinetic investigations, biosynthesis, chemical synthesis and structural modifications, as well as future research directions of the promising natural withanolides. The literature from March 2010 to December 2020 is reviewed, and 287 references are cited.

Involvement of TRPM8 Channel in Radiation-Induced DNA Damage Repair Mechanism Contributing to Radioresistance of B16 Melanoma

Radiation is an effective cancer treatment, but cancer cells can acquire radioresistance, which is associated with increased DNA damage response and enhanced proliferative capacity, and therefore, it is important to understand the intracellular biochemical responses to γ-irradiation. The transient receptor potential melastatin 8 (TRPM8) channel plays roles in the development and progression of tumors, but it is unclear whether it is involved in the DNA damage response induced by γ-irradiation. Here, we show that a TRPM8 channel inhibitor suppresses the DNA damage response (phosphorylated histone variant H2AX-p53-binding protein 1 (γH2AX-53BP1) focus formation) and colony formation of B16 melanoma cells. Furthermore, the TRPM8 channel-specific agonist WS-12 enhanced the DNA damage response and increased the survival fraction after γ-irradiation. We found that the TRPM8 channel inhibitor enhanced G₂/M phase arrest after γ-irradiation. Phosphorylation of ataxia telangiectasia mutated and p53, which both contribute to the DNA damage response was also suppressed after γ-irradiation. In addition, the TRPM8 channel inhibitor enhanced the γ-irradiation-induced suppression of tumor growth in vivo. We conclude that the TRPM8 channel is involved in radiation-induced DNA damage repair and contributes to the radioresistance of B16 melanoma cells. TRPM8 channel inhibitors might be clinically useful as radiosensitizers to enhance radiation therapy of melanoma.

Natural Compounds That Target DNA Repair Pathways and Their Therapeutic Potential to Counteract Cancer Cells

Resistance to current cancer treatments is an important problem that arises through various mechanisms, but one that stands out involves an overexpression of several factors associated with DNA repair. To counteract this type of resistance, different drugs have been developed to affect one or more DNA repair pathways, therefore, to test different compounds of natural origin that have been shown to induce cell death in cancer cells is paramount. Since natural compounds target components of the DNA repair pathways, they have been shown to promote cancer cells to be resensitized to current treatments. For this and other reasons, natural compounds have aroused great curiosity and several research projects are being developed around the world to establish combined treatments between them and radio or chemotherapy. In this work, we summarize the effects of different natural compounds on the DNA repair mechanisms of cancer cells and emphasize their possible application to re-sensitize these cells.

Plant-Based Scaffolds Modify Cellular Response to Drug and Radiation Exposure Compared to Standard Cell Culture Models

Plant-based scaffolds present many advantages over a variety of biomaterials. Recent studies explored their potential to be repopulated with human cells and thus highlight a growing interest for their use in tissue engineering or for biomedical applications. However, it is still unclear if these in vitro plant-based scaffolds can modify cell phenotype or affect cellular response to external stimuli. Here, we report the characterization of the mechano-regulation of melanoma SK-MEL-28 and prostate PC3 cells seeded on decellularized spinach leaves scaffolds, compared to cells deposited on standard rigid cell culture substrate, as well as their response to drug and radiation treatment. The results showed that YAP/TAZ signaling was downregulated, cellular morphology altered and proliferation rate decreased when cells were cultured on leaf scaffold. Interestingly, cell culture on vegetal scaffold also affected cellular response to external stress. Thus, SK-MEL-28 cells phenotype is modified leading to a decrease in MITF activity and drug resistance, while PC3 cells showed altered gene expression and radiation response. These findings shed lights on the decellularization of vegetal materials to provide substrates that can be repopulated with human cells to better reproduce a soft tissue microenvironment. However, these complex scaffolds mediate changes in cell behavior and in order to exploit the capability of matching physical properties of the various plant scaffolds to diverse physiological functionalities of cells and human tissue constructs, additional studies are required to better characterize physical and biochemical cell-substrate interactions.