Effects of thalidomide on growth and VEGF-A expression in SW480 colon cancer cells

Current trends and future prospects of drug repositioning in gastrointestinal oncology

Gastrointestinal (GI) cancers comprise a significant number of cancer cases worldwide and contribute to a high percentage of cancer-related deaths. To improve survival rates of GI cancer patients, it is important to find and implement more effective therapeutic strategies with better prognoses and fewer side effects. The development of new drugs can be a lengthy and expensive process, often involving clinical trials that may fail in the early stages. One strategy to address these challenges is drug repurposing (DR). Drug repurposing is a developmental strategy that involves using existing drugs approved for other diseases and leveraging their safety and pharmacological data to explore their potential use in treating different diseases. In this paper, we outline the existing therapeutic strategies and challenges associated with GI cancers and explore DR as a promising alternative approach. We have presented an extensive review of different DR methodologies, research efforts and examples of repurposed drugs within various GI cancer types, such as colorectal, pancreatic and liver cancers. Our aim is to provide a comprehensive overview of employing the DR approach in GI cancers to inform future research endeavors and clinical trials in this field.

SALL4 promotes angiogenesis in gastric cancer by regulating VEGF expression and targeting SALL4/VEGF pathway inhibits cancer progression

BACKGROUND

Spalt-like protein 4 (SALL4) is a stemness-related transcription factor whose abnormal re-expression contributes to cancer initiation and progression. However, the role of SALL4 in cancer angiogenesis remains unknown.

METHODS

Analyses of clinical specimens via TCGA datasets were performed to determine the expression level and clinical significance of SALL4 in STAD (Stomach Adenocarcinoma). SALL4 knockdown, knockout, and overexpression were achieved by siRNA, CRISPR/Cas9, and plasmid transfection. The effects of conditioned medium (CM) from SALL4 knockdown or overexpression of gastric cancer cells on endothelial cell proliferation, migration, and tube formation were investigated by CCK-8 assay, transwell migration assay, and tube formation assay. The regulation of VEGF gene expression by SALL4 was studied by qRT-PCR, western blot, chromatin immunoprecipitation (ChIP) assay, and electrophoretic mobility shift assay (EMSA). Engineered exosomes from 293T cells loaded with si-SALL4-B and thalidomide were produced to test their therapeutic effect on gastric cancer progression.

RESULTS

SALL4 expression was increased in STAD and positively correlated with tumor progression and poor prognosis. SALL4-B knockdown or knockout decreased while over-expression increased the promotion of human umbilical vein endothelial cells (HUVEC) cell proliferation, migration, and tube formation by gastric cancer cell-derived CM. Further investigation revealed a widespread association of SALL4 with angiogenic gene transcription through the TCGA datasets. Additionally, SALL4-B knockdown reduced, while over-expression enhanced the expression levels of VEGF-A, B, and C genes. The results of ChIP and EMSA assays indicated that SALL4 could directly bind to the promoters of VEGF-A, B, and C genes and activate their transcription, which may be associated with increased histone H3-K79 and H3-K4 modifications in their promoter regions. Furthermore, si-SALL4-B and thalidomide-loaded exosomes could be efficiently uptaken by gastric cancer cells and significantly reduced SALL4-B and Vascular Endothelial Growth Factor (VEGF) expression levels in gastric cancer cells, thus inhibiting the pro-angiogenic role of their derived CM.

CONCLUSION

These findings suggest that SALL4 plays an important role in angiogenesis by transcriptionally regulating VEGF expression. Co-delivery of the functional siRNA and anticancer drug via exosomes represents a useful approach to inhibiting cancer angiogenesis by targeting SALL4/VEGF pathway.

Cancer apelin receptor suppresses vascular mimicry in malignant melanoma

Several reports indicate that apelin is often over-expressed in tumors, and therefore it has been suggested that the apelin-apelin receptor (APJ) system may induce tumor progression. In contrast, our previous research revealed high expression of the apelin-APJ system in tumor blood vessels, suggesting its involvement in the regulation of tumor vessel formation and normalization, resulting in the suppression of tumor growth by promoting the infiltration of T cells. Thus, the effect of the apelin-APJ system on tumors remains controversial. In this report, to clarify the effect of apelin in tumor cells, we analyzed the function of APJ in tumor cells using APJ knock out (KO) mice. In APJ-KO mice, Apelin overexpression in B16/BL6 (B16) melanoma cells induced greater tumor growth than controls. In an APJ-KO melanoma inoculation model, although angiogenesis is suppressed compared to wild type, no difference is evident in tumor growth. We found that APJ deficiency promoted vascular mimicry in tumors. In vitro, cultured APJ-KO B16 cells demonstrated a spindle-like shape. This phenotypic change was thought to be induced by epithelial-mesenchymal transition (EMT) based on evidence that APJ-KO B16 cells show persistently high levels of the mesenchymal maker, Zeb1; however, we found that EMT did not correlate with the transforming growth factor-β/smad signaling pathway in our model. We propose that apelin-APJ system in cancer cells induces tumor growth but negatively regulates EMT and tumor malignancy.

A Novel Nanoemulsion Formula for an Improved Delivery of a Thalidomide Analogue to Triple-Negative Breast Cancer; Synthesis, Formulation, Characterization and Molecular Studies

Background

Thalidomide (THD) and its analogues were recently reported as a promising treatment for different types of solid tumors due to their antiangiogenic effect.

Methods

In this work, we synthesized a novel THD analogue (TA), and its chemistry was confirmed with different techniques such as IR, mass spectroscopy, elemental analysis as well as ¹H and ¹³C NMR. To increase solubility and anticancer efficacy, a new oil in water (O/W) nanoemulsion (NE) was used in the formulation of the analogue. The novel formula's surface charge, size, stability, FTIR, FE-TEM, in vitro drug release and physical characteristics were investigated. Furthermore, molecular docking studies were conducted to predict the possible binding modes and molecular interactions behind the inhibitory activities of the THD and TA.

Results

TA showed a significant cytotoxic activity with IC₅₀ ranging from 0.326 to 43.26 µmol/mL when evaluated against cancerous cells such as MCF-7, HepG2, Caco-2, LNCaP and RKO cell lines. The loaded analogue showed more potential cytotoxicity against MDA-MB-231 and MCF-7-ADR cell lines with IC₅₀ values of 0.0293 and 0.0208 nmol/mL, respectively. Moreover, flow cytometry of cell cycle analysis and apoptosis were performed showing a suppression in the expression levels of TGF-β, MCL-1, VEGF, TNF-α, STAT3 and IL-6 in the MDA-MB-231 cell line.

Conclusion

The novel NE formula dramatically reduced the anticancer dosage of TA from micromolar efficiency to nanomolar efficiency. This indicates that the synthesized analogue exhibited high potency in the NE formulation and proved its efficacy against triple-negative breast cancer cell line.

New phthalimide analog ameliorates CCl4 induced hepatic injury in mice via reducing ROS formation, inflammation, and apoptosis

The present study aimed, for the first time, to examine the biochemical effects of new phthalimide analog, 2-[2-(2-Bromo-1-ethyl-1H-indol-3-yl) ethyl]-1H-isoindole-1,3(2H)-dione, compared to thalidomide drug against liver injury induced in mice. Carbon tetrachloride was intraperitoneal injected in mice for 6 consecutive weeks at a dose of 0.4 mL/kg twice a week for liver injury induction. Histopathological examination, levels of malondialdehyde, nitric oxide, and antioxidant enzymes were determined. Additionally, the protein levels of vascular endothelial growth factor, proliferating cell nuclear protein, tumor necrosis factor-alfa, nuclear factor kappa B-p65, B-cell lymphoma-2, and cysteine-aspartic acid protease-3 were determined. Results revealed that the treatment with phthalimide analog improved the detected liver damage and presented an obvious antioxidant activity through decreasing malondialdehyde and nitric oxide levels accompanied by increasing the levels of the antioxidant enzymes. Furthermore, the analog exhibited an effective inhibitory activity towards the studied protein expressions in liver tissues. Moreover, the B-cell lymphoma-2 protein level was increased while the cysteine-aspartic acid protease-3 level was suppressed after the treatment with phthalimide analog. Together, these results propose that phthalimide analog can ameliorate carbon tetrachloride-induced liver injury in mice through its potent inhibition mediating effect in oxidative stress, inflammation, and apoptosis mechanisms.

Repurposing Cardiac Glycosides: Drugs for Heart Failure Surmounting Viruses

Drug repositioning is a successful approach in medicinal research. It significantly simplifies the long-term process of clinical drug evaluation, since the drug being tested has already been approved for another condition. One example of drug repositioning involves cardiac glycosides (CGs), which have, for a long time, been used in heart medicine. Moreover, it has been known for decades that CGs also have great potential in cancer treatment and, thus, many clinical trials now evaluate their anticancer potential. Interestingly, heart failure and cancer are not the only conditions for which CGs could be effectively used. In recent years, the antiviral potential of CGs has been extensively studied, and with the ongoing SARS-CoV-2 pandemic, this interest in CGs has increased even more. Therefore, here, we present CGs as potent and promising antiviral compounds, which can interfere with almost any steps of the viral life cycle, except for the viral attachment to a host cell. In this review article, we summarize the reported data on this hot topic and discuss the mechanisms of antiviral action of CGs, with reference to the particular viral life cycle phase they interfere with.

Vascular mimicry: Triggers, molecular interactions and in vivo models

Vascular mimicry is induced by a wide array of genes with functions related to cancer stemness, hypoxia, angiogenesis and autophagy. Vascular mimicry competent (VM-competent) cells that form de novo blood vessels are common in solid tumors facilitating tumor cell survival and metastasis. VM-competent cells display increased levels of vascular mimicry selecting for stem-like cells in an O₂-gradient-dependent manner in deeply hypoxic tumor regions, while also aiding in maintaining tumor cell metabolism and stemness. Three of the principal drivers of vascular mimicry are EphA2, Nodal and HIF-1α, however, directly or indirectly many of these molecules affect VE-Cadherin (VE-Cad), which forms gap-junctions to bind angiogenic blood vessels together. During vascular mimicry, the endothelial-like functions of VM-competent cancer stem cells co-opt VE-Cad to bind cancer cells together to create cancer cell-derived blood conducting vessels. This process potentially compensates for the lack of access to blood and nutrient in avascular tumors, simultaneously providing nutrients and enhancing cancer invasion and metastasis. Current evidence also supports that vascular mimicry promotes cancer malignancy and metastasis due to the cooperation of oncogenic signaling molecules driving cancer stemness and autophagy. While a number of currently used cancer therapeutics are effective inhibitors of vascular mimicry, developing a new class of vascular mimicry specific inhibitors could allow for the treatment of angiogenesis-resistant tumors, inhibit cancer metastasis and improve patient survival. In this review, we describe the principal vascular mimicry pathways in addition to emphasizing the roles of hypoxia, autophagy and select proangiogenic oncogenes in this process.

Colorectal Cancer: An Update on Treatment Options and Future Perspectives

Throughout the years, colorectal cancer has steadily become a global health problem. While other types of cancers have seen a decline in cases because of screening and vaccination programs, colorectal cancer has risen become the third most diagnosed cancer worldwide and, more worryingly, the second leading cancer-related cause of death. The introduction of targeted therapy has been widely considered a major paradigm shift in the treatment of colorectal cancer, which agents such as bevacizumab and cetuximab quickly becoming mainstay options in the treatment of locally advanced or metastatic disease. However, this type of treatment has also shown its limitations, with limited or no benefit for a large portion of the patients. With more and more knowledge being gathered on the molecular mechanisms which govern the malignant phenotype presented by colorectal cancer, scientists are engaged in a continuous effort to develop new therapies based on these discoveries.

SMYD2-OE promotes oxaliplatin resistance in colon cancer through MDR1/P-glycoprotein via MEK/ERK/AP1 pathway

Background

SET and MYND domain-containing protein 2 (SMYD2-OE) plays an important role in cancer development through methylating histone and non-histone proteins. However, little is known about the relevance of SMYD2-OE in colon cancer. Moreover, oxaliplatin (L-OHP) is applied as first line for colon cancer chemotherapy, but drug resistance restricts its efficacy. Unexpectedly, the mechanism of L-OHP resistance in colon cancer remains unclear. In this study, we investigated the relationship of SMYD2-OE expression and L-OHP resistance in colon cancer and further explored the underlying mechanism linking SMYD2-OE, L-OHP resistance, and colon cancer.

Materials and methods

Expression levels of SMYD2-OE in colon cancer tissues of patients were tested. In vitro and in vivo assays were conducted to explore the function and mechanism of SMYD2-OE in colon cancer sensitivity to L-OHP.

Results

SMYD2-OE was overexpressed in colon cancer tissues compared with non-neoplastic tissues and associated with poor prognosis of patients with colon cancer after L-OHP-based chemotherapy. Knockdown of SMYD2-OE increased colon cancer sensitivity to L-OHP in vitro and in vivo. However, SMYD2-OE overexpression promoted L-OHP resistance in colon cancer cell in vitro. In addition, SMYD2-OE could upregulate MDR1/P-glycoprotein expression depending on MEK/ERK/AP-1 signaling pathway activity.

Conclusion

These results imply that SMYD2-OE promotes L-OHP resistance in colon cancer by regulating MDR1/P-glycoprotein through MEK/ERK/AP-1 signaling pathway, providing a potential strategy to sensitize chemotherapy by SMYD2-OE knockdown in colon cancer treatment.