Early Molecular Events in Murine Gastric Epithelial Cells Mediated by Helicobacter pylori CagA

Revisiting Luteolin Against the Mediators of Human Metastatic Colorectal Carcinoma: A Biomolecular Approach

Metastatic colorectal carcinoma (mCRC) is one of the prevalent subtypes of human cancers and is caused by the alterations of various lifestyle and diet-associated factors. β-catenin, GSK-3β, PI3K-α, AKT1, and NF-κB p50 are known to be the critical regulators of tumorigenesis and immunopathogenesis of mCRC. Unfortunately, current drugs have limited efficacy, side effects and can lead to chemoresistance. Therefore, searching for a nontoxic, efficacious anti-mCRC agent is crucial and of utmost interest. The present study demonstrates the identification of a productive and nontoxic anti-mCRC agent through a five-targets (β-catenin, GSK-3β, PI3K-α, AKT1, and p50)-based and three-tier (binding affinity, pharmacokinetics, and pharmacophore) screening strategy involving a series of 30 phytocompounds having a background of anti-inflammatory/anti-mCRC efficacy alongside 5-fluorouracil (FU), a reference drug. Luteolin (a phyto-flavonoid) was eventually rendered as the most potent and safe phytocompound. This inference was verified through three rounds of validation. Firstly, luteolin was found to be effective against the different mCRC cell lines (HCT-15, HCT-116, DLD-1, and HT-29) without hampering the viability of non-tumorigenic ones (RWPE-1). Secondly, luteolin was found to curtail the clonogenicity of CRC cells, and finally, it also disrupted the formation of colospheroids, a characteristic of metastasis. While studying the mechanistic insights, luteolin was found to inhibit β-catenin activity (a key regulator of mCRC) through direct physical interactions, promoting its degradation by activating GSK3-β and ceasing its activation by inactivating AKT1 and PI3K-α. Luteolin also inhibited p50 activity, which could be useful in mitigating mCRC-associated proinflammatory milieu. In conclusion, our study provides evidence on the efficacy of luteolin against the critical key regulators of immunopathogenesis of mCRC and recommends further studies in animal models to determine the effectiveness efficacy of this natural compound for treating mCRC in the future.

Melatonin and andrographolide synergize to inhibit the colospheroid phenotype by targeting Wnt/beta-catenin signaling

β-catenin signaling, and angiogenesis are associated with colospheroid (CSC), development. CSCs, spheroids derived from colon cancer cells, are responsible for metastasis, drug resistance, and disease recurrence. Whether dysregulating β-catenin and inhibiting angiogenesis reduce CSC growth is unknown. In this study, the molecular mechanism of CSC growth inhibition was evaluated using a novel combination of melatonin (MLT) and andrographolide (AGP). These drugs have anticarcinogenic, antioxidant, and antimetastatic properties. CSCs were obtained from two metastatic colon cancer cell lines (HT29 and HCT-15). The viability and stemness were monitored (FDA propidium iodide staining and immunoblot for CD44, CD133, Nanog, Sox2, and Oct4). The drug combination synergistically diminished stemness via increased reactive oxygen species (ROS) levels, reduced mitochondrial membrane potential and ATP level. MLT + AGP induced cell death by inhibiting β-catenin expression and its downregulatory signals, Cyclin D1, c-Myc. MLT + AGP treated cells exhibited translocation of phospho-β-catenin to the nucleus and dephosphorylated-β-catenin. Downregulation of β-catenin activation and its transcription factors (TCF4 and LEF1) and GTP binding/G-protein related activity were found in the dual therapy. Angiogenic inhibition is consistent with downregulation of VEGF messenger RNA transcripts (VEGF189), phosphorylated VEGF receptor protein expression, matrigel invasion, and capillary tube inhibition. In vivo, the intravenous injection of MLT + AGP slowed HT29 metastatic colon cancer. Histopathology indicated significant reduction in microvascular density and tumor index. Immunohistochemistry for caspase 7, and β-catenin found increased apoptosis and downregulation of β-catenin signals. The mechanism(s) of decreased colospheroids growth were the inhibition of the Wnt/β-catenin pathway. Our results provide a rationale for using MLT in combination with AGP for the inhibition of CRCs.

Animal Models and Helicobacter pylori Infection

Helicobacter pylori colonize the gastric mucosa of at least half of the world’s population. Persistent infection is associated with the development of gastritis, peptic ulcer disease, and an increased risk of gastric cancer and gastric-mucosa-associated lymphoid tissue (MALT) lymphoma. In vivo studies using several animal models have provided crucial evidence for understanding the pathophysiology of H. pylori-associated complications. Numerous animal models, such as Mongolian gerbils, transgenic mouse models, guinea pigs, and other animals, including non-human primates, are being widely used due to their persistent association in causing gastric complications. However, finding suitable animal models for in vivo experimentation to understand the pathophysiology of gastric cancer and MALT lymphoma is a complicated task. In this review, we summarized the most appropriate and latest information in the scientific literature to understand the role and importance of H. pylori infection animal models.

Impact of Andrographolide and Melatonin Combinatorial Drug Therapy on Metastatic Colon Cancer Cells and Organoids

Background:

The death rate (the number of deaths per 100 000 people per year) of colorectal cancer (CRC) has been dropping since 1980 due to increased screening, lifestyle-related risk factors, and improved treatment options; however, CRC is the third leading cause of cancer-related deaths in men and women in the United States. Therefore, successful therapy for CRC is an unmet clinical need. This study aimed to investigate the impacts of andrographolide (AGP) and melatonin (MLT) on CRC and the underlying mechanism.

Methods:

To investigate AGP and MLT anticancer effects, a series of metastatic colon cancer cell lines (T84, Colo 205, HT-29, and DLD-1) were selected. In addition, a metastatic patient-derived organoid model (PDOD) was used to monitor the anticancer effects of AGP and MLT. A series of bioassays including 3D organoid cell culture, MTT, colony formation, western blotting, immunofluorescence, and quantitative polymerase chain reaction (qPCR) were performed.

Results:

The dual therapy significantly promotes CRC cell death, as compared with the normal cells. It also limits CRC colony formation and disrupts the PDOD membrane integrity along with decreased Ki-67 expression. A significantly higher cleaved caspase-3 and the endoplasmic reticulum (ER) stress proteins, IRE-1 and ATF-6 expression, by 48 hours were found. This combinatorial treatment increased reactive oxygen species (ROS) levels. Apoptosis signaling molecules BAX, XBP-1, and CHOP were significantly increased as determined by qPCR.

Conclusions:

These findings indicated that AGP and MLT associated ER stress-mediated apoptotic metastatic colorectal cancer (mCRC) cell death through the IRE-1/XBP-1/CHOP signaling pathway. This novel combination could be a potential therapeutic strategy for mCRC cells.

Synergistic potential of dual andrographolide and melatonin targeting of metastatic colon cancer cells: Using the Chou-Talalay combination index method

Colorectal cancer (CRC) mortality has diminished for decades due to new and improved treatment profiles. However, CRC still ranks as the third most diagnosed cancer in the US. Therefore, a new therapeutic approach is needed to overcome colospheroids inhibition and drug resistance. It is well documented that andrographolide (AGP) and melatonin (MLT) have anti-carcinogenic properties. Our goal was to evaluate their synergistic effects on metastatic colon cancer cells (mCRC) and colospheroids. HT-29 and HCT-15 mCRC cells were simultaneously treated with serial dilutions of AGP and MLT for 24, 48 and 72 h. Cell viability was monitored using the MTT assay. The Chou-Talalay method for drug combination is based on the median effect equation, providing a theoretical basis for the combination index and the isobologram equation. This allows quantitative determination of drug interactions using the CompuSyn software, where CI < 1, = 1, and >1 indicates synergistic, additive, and antagonistic effects respectively. Our results demonstrate that AGP and MLT in combination show synergism with CI values of 0.35293 and 0.34152 for HT-29 and HCT-15 respectively and a fractional inhibition of Fa = 0.50-0.90, as shown by the Fa-CI plot and isobologram. The synergism value was validated in colospheroids (HT-29-s and HCT-15-s) based on morphology, viability, and colony formation and in 5-FU drug resistant cell (HT-29R and HCT-116R) viability. The mechanism(s) of decreased cell viability are due to the induction of ER stress proteins and angiogenic inhibition. Our results provide rationale for using AGP in combination with MLT on mCRC.