Cellular prion protein regulates invasion and migration of breast cancer cells through MMP-9 activity

The role of cellular prion protein in immune system

Numerous studies have investigated the cellular prion protein (PrPC) since its discovery. These investigations have explained that its structure is predominantly composed of alpha helices and short beta sheet segments, and when its abnormal scrapie isoform (PrPSc) is infected, PrPSc transforms the PrPC, leading to prion diseases, including Creutzfeldt-Jakob disease in humans and bovine spongiform encephalopathy in cattle. Given its ubiquitous distribution across a variety of cellular types, the PrPC manifests a diverse range of biological functions, including cell-cell adhesion, neuroprotection, signalings, and oxidative stress response. PrPC is also expressed in immune tissues, and its functions in these tissues include the activation of immune cells and the formation of secondary lymphoid tissues, such as the spleen and lymph nodes. Moreover, high expression of PrPC in immune cells plays a crucial role in the pathogenesis of prion diseases. In addition, it affects inflammation and the development and progression of cancer via various mechanisms. In this review, we discuss the studies on the role of PrPC from various immunological perspectives. [BMB Reports 2023; 56(12): 645-650].

The Multifaceted Functions of Prion Protein (PrPC) in Cancer

The cellular prion protein (PrPC) is a glycoprotein anchored to the cell surface by glycosylphosphatidylinositol (GPI). PrPC is expressed both in the brain and in peripheral tissues. Investigations on PrPC's functions revealed its direct involvement in neurodegenerative and prion diseases, as well as in various physiological processes such as anti-oxidative functions, copper homeostasis, trans-membrane signaling, and cell adhesion. Recent findings have revealed the ectopic expression of PrPC in various cancers including gastric, melanoma, breast, colorectal, pancreatic, as well as rare cancers, where PrPC promotes cellular migration and invasion, tumor growth, and metastasis. Through its downstream signaling, PrPC has also been reported to be involved in resistance to chemotherapy and tumor cell apoptosis. This review summarizes the variance of expression of PrPC in different types of cancers and discusses its roles in their development and progression, as well as its use as a potential target to treat such cancers.

Emerging roles of the cellular prion protein (PrPC) and 37/67 kDa laminin receptor (RPSA) interaction in cancer biology

The cellular prion protein (PrPC) is well-known for its involvement, under its pathogenic protease-resistant form (PrPSc), in a group of neurodegenerative diseases, known as prion diseases. PrPC is expressed in nervous system, as well as in other peripheral organs, and has been found overexpressed in several types of solid tumors. Notwithstanding, studies in recent years have disclosed an emerging role for PrPC in various cancer associated processes. PrPC has high binding affinity for 37/67 kDa laminin receptor (RPSA), a molecule that acts as a key player in tumorigenesis, affecting cell growth, adhesion, migration, invasion and cell death processes. Recently, we have characterized at cellular level, small molecules able to antagonize the direct PrPC binding to RPSA and their intracellular trafficking. These findings are very crucial considering that the main function of RPSA is to modulate key events in the metastasis cascade. Elucidation of the role played by PrPC/RPSA interaction in regulating tumor development, progression and response to treatment, represents a very promising challenge to gain pathogenetic information and discover novel specific biomarkers and/or therapeutic targets to be exploited in clinical settings. This review attempts to convey a detailed description of the complexity surrounding these multifaceted proteins from the perspective of cancer hallmarks, but with a specific focus on the role of their interaction in the control of proliferation, migration and invasion, genome instability and mutation, as well as resistance to cell death controlled by autophagic pathway.

Detailing the ultrastructure's increase of prion protein in pancreatic adenocarcinoma

BACKGROUND

Recent evidences have shown a relationship between prion protein (PrPc) expression and pancreatic ductal adenocarcinoma (PDAC). Indeed, PrPc could be one of the markers explaining the aggressiveness of this tumor. However, studies investigating the specific compartmentalization of increased PrPc expression within PDAC cells are lacking, as well as a correlation between ultrastructural evidence, ultrastructural morphometry of PrPc protein and clinical data. These data, as well as the quantitative stoichiometry of this protein detected by immuno-gold, provide a significant advancement in understanding the biology of disease and the outcome of surgical resection.

AIM

To analyze quantitative stoichiometry and compartmentalization of PrPc in PDAC cells and to correlate its presence with prognostic data.

METHODS

Between June 2018 and December 2020, samples from pancreatic tissues of 45 patients treated with pancreatic resection for a preoperative suspicion of PDAC at our Institution were collected. When the frozen section excluded a PDAC diagnosis, or the nodules were too small for adequate sampling, patients were ruled out from the present study. Western blotting was used to detect, quantify and compare the expression of PrPc in PDAC and control tissues, such as those of non-affected neighboring pancreatic tissue of the same patient. To quantify the increase of PrPc and to detect the subcellular compartmentalization of PrPc within PDAC cells, immuno-gold stoichiometry within specific cell compartments was analyzed with electron microscopy. Finally, an analysis of quantitative PrPc expression according to prognostic data, such as cancer stage, recurrence of the disease at 12 mo after surgery and recurrence during adjuvant chemotherapy was made.

RESULTS

The amount of PrPc within specimen from 38 out of 45 patients was determined by semi-quantitative analysis by using Western blotting, which indicates that PrPc increases almost three-fold in tumor pancreatic tissue compared with healthy pancreatic regions [242.41 ± 28.36 optical density (OD) vs 95 ± 17.40 OD, P < 0.0001]. Quantitative morphometry carried out by using immuno-gold detection at transmission electron microscopy confirms an increased PrPc expression in PDAC ductal cells of all patients and allows to detect a specific compartmentalization of PrPc within tumor cells. In particular, the number of immuno-gold particles of PrPc was significantly higher in PDAC cells respect to controls, when considering the whole cell (19.8 ± 0.79 particles vs 9.44 ± 0.45, P < 0.0001). Remarkably, considering PDAC cells, the increase of PrPc was higher in the nucleus than cytosol of tumor cells, which indicates a shift in PrPc compartmentalization within tumor cells. In fact, the increase of immuno-gold within nuclear compartment exceeds at large the augment of PrPc which was detected in the cytosol (nucleus: 12.88 ± 0.59 particles vs 5.12 ± 0.32, P < 0.0001; cytosol: 7.74. ± 0.44 particles vs 4.3 ± 0.24, P < 0.0001). In order to analyze the prognostic impact of PrPc, we found a correlation between PrPc expression and cancer stage according to pathology results, with a significantly higher expression of PrPc for advanced stages. Moreover, 24 patients with a mean follow-up of 16.8 mo were considered. Immuno-blot analysis revealed a significantly higher expression of PrPc in patients with disease recurrence at 12 mo after radical surgery (360.71 ± 69.01 OD vs 170.23 ± 23.06 OD, P = 0.023), also in the subgroup of patients treated with adjuvant CT (368.36 ± 79.26 OD in the recurrence group vs 162.86 ± 24.16 OD, P = 0.028), which indicates a correlation with a higher chemo-resistance.

CONCLUSION

Expression of PrPc is significantly higher in PDAC cells compared with control, with the protein mainly placed in the nucleus. Preliminary clinical data confirm the correlation with a poorer prognosis.

The Cellular Prion Protein and the Hallmarks of Cancer

Simple Summary

The cellular prion protein PrP^C is best known for its involvement, under its pathogenic isoform, in a group of neurodegenerative diseases. Notwithstanding, an emerging role for PrP^C in various cancer-associated processes has attracted increasing attention over recent years. PrP^C is overexpressed in diverse types of solid cancers and has been incriminated in various aspects of cancer biology, most notably proliferation, migration, invasion and metastasis, as well as resistance to cytotoxic agents. This article aims to provide a comprehensive overview of the current knowledge of PrP^C with respect to the hallmarks of cancer, a reference framework encompassing the major characteristics of cancer cells.

Abstract

Beyond its causal involvement in a group of neurodegenerative diseases known as Transmissible Spongiform Encephalopathies, the cellular prion protein PrP^C is now taking centre stage as an important contributor to cancer progression in various types of solid tumours. The prion cancer research field has progressively expanded in the last few years and has yielded consistent evidence for an involvement of PrP^C in cancer cell proliferation, migration and invasion, therapeutic resistance and cancer stem cell properties. Most recent data have uncovered new facets of the biology of PrP^C in cancer, ranging from its control on enzymes involved in immune tolerance to its radio-protective activity, by way of promoting angiogenesis. In the present review, we aim to summarise the body of literature dedicated to the study of PrP^C in relation to cancer from the perspective of the hallmarks of cancer, the reference framework defined by Hanahan and Weinberg.

Tumor resistance to radiotherapy is triggered by an ATM/TAK1-dependent-increased expression of the cellular prion protein

In solid cancers, high expression of the cellular prion protein (PrPC) is associated with stemness, invasiveness, and resistance to chemotherapy, but the role of PrPC in tumor response to radiotherapy is unknown. Here, we show that, in neuroblastoma, breast, and colorectal cancer cell lines, PrPC expression is increased after ionizing radiation (IR) and that PrPC deficiency increases radiation sensitivity and decreases radiation-induced radioresistance in tumor cells. In neuroblastoma cells, IR activates ATM that triggers TAK1-dependent phosphorylation of JNK and subsequent activation of the AP-1 transcription factor that ultimately increases PRNP promoter transcriptional activity through an AP-1 binding site in the PRNP promoter. Importantly, we show that this ATM-TAK1-PrPC pathway mediated radioresistance is activated in all tumor cell lines studied and that pharmacological inhibition of TAK1 activity recapitulates the effects of PrPC deficiency. Altogether, these results unveil how tumor cells activate PRNP to acquire resistance to radiotherapy and might have implications for therapeutic targeting of solid tumors radioresistance.

Prion protein is associated with a worse prognosis of head and neck squamous cell carcinoma

BACKGROUND

Head and neck squamous cell carcinoma (HNSC) etiopathogenesis remains unclear, and the biological changes with the activation of heat shock proteins (HSPs) and prion protein (PRNP) promoted by hypoxia in HNSC are undetermined. This study investigates hypoxia's effect in lymph node metastasis by PRNP expression changes and its main partners.

METHODS

The study combined a theoretical/cell culture study with a case-control study. First, bioinformatics and cell culture were performed. A case-control study was performed in a second step by comparing HNSC patients with and without lymph node metastasis.

ANALYSES

The Cancer Genome Atlas (TCGA) data source validates the theory in the global population study.

RESULTS

Bioinformatics analysis suggests that hypoxia-inducible factor-1α (HIF1A) is associated with HSPA4, HSP90AA1 and PRNP expression. TCGA data validate the hypothesis that higher HSP90AA1, HSPA4 and PRNP are related to metastases and low survival. Herein, the cell study demonstrated that muted PRNP did not respond to hypoxia.

DISCUSSION

Our results collectively provide the first evidence that PRNP promotes HNSC lymph node metastasis progression through the upregulation of HSPA4, HSP90AA1 and HIF1A. Our findings may provide a molecular basis for the promoting Role of PRNP in HNSC progression.

Involvement of Cellular Prion Protein in Invasion and Metastasis of Lung Cancer by Inducing Treg Cell Development

The cellular prion protein (PrP^C) is a cell surface glycoprotein expressed in many cell types that plays an important role in normal cellular processes. However, an increase in PrP^C expression has been associated with a variety of human cancers, where it may be involved in resistance to the proliferation and metastasis of cancer cells. PrP-deficient (Prnp^0/0) and PrP-overexpressing (Tga20) mice were studied to evaluate the role of PrP^C in the invasion and metastasis of cancer. Tga20 mice, with increased PrP^C, died more quickly from lung cancer than did the Prnp^0/0 mice, and this effect was associated with increased transforming growth factor-beta (TGF-β) and programmed death ligand-1 (PD-L1), which are important for the development and function of regulatory T (Treg) cells. The number of FoxP3⁺CD25⁺ Treg cells was increased in Tga20 mice compared to Prnp^0/0 mice, but there was no significant difference in either natural killer or cytotoxic T cell numbers. In addition, mice infected with the ME7 scrapie strain had decreased numbers of Treg cells and decreased expression of TGF-β and PD-L1. These results suggest that PrP^C plays an important role in invasion and metastasis of cancer cells by inducing Treg cells through upregulation of TGF-β and PD-L1 expression.

The Role of Cellular Prion Protein in Promoting Stemness and Differentiation in Cancer

Simple Summary

Aside from its well-established role in prion disorders, in the last decades the significance of cellular prion protein (PrP^C) expression in human cancers has attracted great attention. An extensive body of work provided evidence that PrP^C contributes to tumorigenesis by regulating tumor growth, differentiation, and resistance to conventional therapies. In particular, PrP^C over-expression has been related to the acquisition of a malignant phenotype of cancer stem cells (CSCs) in a variety of solid tumors, encompassing pancreatic ductal adenocarcinoma, osteosarcoma, breast, gastric, and colorectal cancers, and primary brain tumors as well. According to consensus, increased levels of PrP^C endow CSCs with self-renewal, proliferative, migratory, and invasive capacities, along with increased resistance to anti-cancer agents. In addition, increasing evidence demonstrates that PrPc also participates in multi-protein complexes to modulate the oncogenic properties of CSCs, thus sustaining tumorigenesis. Therefore, strategies aimed at targeting PrP^C and/or PrP^C-organized complexes could be a promising approach for anti-cancer therapy.

Abstract

Cellular prion protein (PrP^C) is seminal to modulate a variety of baseline cell functions to grant homeostasis. The classic role of such a protein was defined as a chaperone-like molecule being able to rescue cell survival. Nonetheless, PrP^C also represents the precursor of the deleterious misfolded variant known as scrapie prion protein (PrP^Sc). This variant is detrimental in a variety of prion disorders. This multi-faceted role of PrP is greatly increased by recent findings showing how PrP^C in its folded conformation may foster tumor progression by acting at multiple levels. The present review focuses on such a cancer-promoting effect. The manuscript analyzes recent findings on the occurrence of PrP^C in various cancers and discusses the multiple effects, which sustain cancer progression. Within this frame, the effects of PrP^C on stemness and differentiation are discussed. A special emphasis is provided on the spreading of PrP^C and the epigenetic effects, which are induced in neighboring cells to activate cancer-related genes. These detrimental effects are further discussed in relation to the aberrancy of its physiological and beneficial role on cell homeostasis. A specific paragraph is dedicated to the role of PrP^C beyond its effects in the biology of cancer to represent a potential biomarker in the follow up of patients following surgical resection.

Characterizing the effect of substrate stiffness on the extravasation potential of breast cancer cells using a 3D microfluidic model

Different biochemical and biomechanical cues from tumor microenvironment affect the extravasation of cancer cells to distant organs; among them, the mechanical signals are poorly understood. Although the effect of substrate stiffness on the primary migration of cancer cells has been previously probed, its role in regulating the extravasation ability of cancer cells is still vague. Herein, we used a microfluidic device to mimic the extravasation of tumor cells in a 3D microenvironment containing cancer cells, endothelial cells, and the biological matrix. The microfluidic-based extravasation model was utilized to probe the effect of substrate stiffness on the invasion ability of breast cancer cells. MCF7 and MDA-MB-231 cancer cells were cultured among substrates with different stiffness which followed by monitoring their extravasation capability through the microfluidic device. Our results demonstrated that acidic collagen at a concentration of 2.5 mg/ml promotes migration of cancer cells. Additionally, the substrate softening resulted in up to 46% reduction in the invasion of breast cancer cells. The substrate softening not only affected the number of extravasated cells but also reduced their migration distance up to 53%. We further investigated the secreted level of matrix metalloproteinase 9 (MMP9) and identified that there is a positive correlation between substrate stiffening, MMP9 concentration, and extravasation of cancer cells. These findings suggest that the substrate stiffness mediates the cancer cells extravasation in a microfluidic model. Changes in MMP9 level could be one of the possible underlying mechanisms which need more investigations to be addressed thoroughly.

Prion Protein at the Leading Edge: Its Role in Cell Motility

Cell motility is a central process involved in fundamental biological phenomena during embryonic development, wound healing, immune surveillance, and cancer spreading. Cell movement is complex and dynamic and requires the coordinated activity of cytoskeletal, membrane, adhesion and extracellular proteins. Cellular prion protein (PrPC) has been implicated in distinct aspects of cell motility, including axonal growth, transendothelial migration, epithelial-mesenchymal transition, formation of lamellipodia, and tumor migration and invasion. The preferential location of PrPC on cell membrane favors its function as a pivotal molecule in cell motile phenotype, being able to serve as a scaffold protein for extracellular matrix proteins, cell surface receptors, and cytoskeletal multiprotein complexes to modulate their activities in cellular movement. Evidence points to PrPC mediating interactions of multiple key elements of cell motility at the intra- and extracellular levels, such as integrins and matrix proteins, also regulating cell adhesion molecule stability and cell adhesion cytoskeleton dynamics. Understanding the molecular mechanisms that govern cell motility is critical for tissue homeostasis, since uncontrolled cell movement results in pathological conditions such as developmental diseases and tumor dissemination. In this review, we discuss the relevant contribution of PrPC in several aspects of cell motility, unveiling new insights into both PrPC function and mechanism in a multifaceted manner either in physiological or pathological contexts.

Prion protein modulates endothelial to mesenchyme-like transition in trabecular meshwork cells: Implications for primary open angle glaucoma

Endothelial-to-mesenchyme-like transition (Endo-MT) of trabecular meshwork (TM) cells is known to be associated with primary open angle glaucoma (POAG). Here, we investigated whether the prion protein (PrP^C), a neuronal protein known to modulate epithelial-to-mesenchymal transition in a variety of cell types, is expressed in the TM, and plays a similar role at this site. Using a combination of primary human TM cells and human, bovine, and PrP-knock-out (PrP^−/−) mouse models, we demonstrate that PrP^C is expressed in the TM of all three species, including endothelial cells lining the Schlemm’s canal. Silencing of PrP^C in primary human TM cells induces aggregation of β1-integrin and upregulation of α-smooth muscle actin, fibronectin, collagen 1A, vimentin, and laminin, suggestive of transition to a mesenchyme-like phenotype. Remarkably, intraocular pressure is significantly elevated in PrP^−/− mice relative to wild-type controls, suggesting reduced pliability of the extracellular matrix and increased resistance to aqueous outflow in the absence of PrP^C. Since PrP^C is cleaved by members of the disintegrin and matrix-metalloprotease family that are increased in the aqueous humor of POAG arising from a variety of conditions, it is likely that concomitant cleavage of PrP^C exaggerates and confounds the pathology by inducing Endo-MT-like changes in the TM.

Cellular prion protein transcriptionally regulated by NFIL3 enhances lung cancer cell lamellipodium formation and migration through JNK signaling

Tumor invasion and metastasis are the major causes of treatment failure and mortality in lung cancer patients. In this study, we identified a group of genes with differential expression in in situ and invasive lung adenocarcinoma tissues by expression profiling; among these genes we further characterized the association of the upregulation of PRNP, the gene encoding cellular Prion protein (PrPc), with lung adenocarcinoma invasiveness. Immunohistochemistry on clinical specimens showed an association of PrPc expression with invasive but not in situ lung adenocarcinoma. Consistently, the expression of PrPc was higher in the highly invasive than in the lowly invasive lung adenocarcinoma cell lines. Knockdown of PrPc expression in cultured lung adenocarcinoma cells decreased their lamellipodium formation, in vitro migration and invasion, and in vivo experimental lung metastasis. Phosphorylation of JNKs was found to correlate with PrPc expression and the inhibition of JNKs suppressed the PrPc-induced up-regulation of lamellipodium formation, cell migration, and invasion. Moreover, we identified the nuclear factor, interleukin 3 regulated (NFIL3) protein as a transcriptional activator of the PRNP promoter. Accordingly, NFIL3 promoted lung cancer cell migration and invasion in a PrPc-dependent manner. High NFIL3 expression in clinical specimens of lung adenocarcinoma was also associated with tumor invasiveness. Overall, our observations suggest that the NFIL3/PrPc axis, through regulating lamellipodium formation and cell mobility via JNK signaling, plays a critical role in lung cancer invasiveness and metastasis.

Design and Synthesis of Novel Thioethers Derived from 1,5-Diphenyl-6- thioxo-6,7-dihydro-1H-pyrazolo[3,4-d]pyrimidin-4(5H)-ones as Antiangiogenic Agents

Background:

In attempts to discover new antiangiogenic entities, a novel series of thioethers derived from 6-thioxo-6,7-dihydro-1H-pyrazolo[3,4-d]pyrimidine-4(5H)ones was considered and designed. </P><P> Methods: Virtual screening was carried out through docking of the compounds into the vascular endothelial growth factor and matrix metalloproteinase-9 binding sites. Molecular docking studies were performed using Lamarckian Genetic Algorithm. Compounds possessing lowest ligandprotein pairwise interaction energies were synthesized and screened for their antiproliferative activities against five cancer cell lines namely MHCC97H (liver), MDA-MB 231 (Breast), Colo205 (Colon), A549 (lung), A498 (kidney) and IC50 values were determined for the most potent compounds. Additionally, they were tested for their antiangiogenic activities by testing their ability to inhibit Human Umbilical Vein Endothelial Cell (HUVEC), cord formation and migration in response to chemoattractant.

Results:

Three compounds 2a, 2b and 5b showed significant antiangiogenic activities. The allyl thioether 2b was the most active with chemotaxis activity data nearly comparable to that of the positive control, TNP-470. Additionally, 2a, 2b and 5b, contrary to TNP-470, interfered with the migration of HUVECs in response to vascular endothelial growth factor rather than endothelial cells proliferation or cord formation. Compounds 2a, 2b and 5b were also investigated for their inhibitory effects on MMPs to investigate the relationship between their angiogenic activity and MMPs. Results revealed that compound 2b was the most effective MMP-9 inhibitor in this series. Additionally, compound 2b reduced the expression levels of VEGF and pERK1/2.

Conclusion:

Our results suggest that compound 2b is considered as a promising antiangiogenic agent by targeting VEGF and MMP-9.

Organization of GPI-anchored proteins at the cell surface and its physiopathological relevance

Glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) are a class of proteins attached to the extracellular leaflet of the plasma membrane via a post-translational modification, the glycolipid anchor. The presence of both glycolipid anchor and protein portion confers them unique features. GPI-APs are expressed in all eukaryotes, from fungi to plants and animals. They display very diverse functions ranging from enzymatic activity, signaling, cell adhesion, cell wall metabolism, neuritogenesis, and immune response. Likewise other plasma membrane proteins, the spatio-temporal organization of GPI-APs is critical for their biological activities in physiological conditions. In this review, we will summarize the latest findings on plasma membrane organization of GPI-APs and the mechanism of its regulation in different cell types. We will also examine the involvement of specific GPI-APs namely the prion protein PrP^C, the Folate Receptor alpha and the urokinase plasminogen activator receptor in human diseases focusing on neurodegenerative diseases and cancer.

Propyl Gallate Exerts an Antimigration Effect on Temozolomide-Treated Malignant Glioma Cells through Inhibition of ROS and the NF-κB Pathway

In this study, we demonstrated that temozolomide (TMZ) and propyl gallate (PG) combination enhanced the inhibition of migration in human U87MG glioma cells. PG inhibited the TMZ-induced reactive oxygen species (ROS) generation. The mitochondrial complex III and NADPH oxidase are two critical sites that can be considered to regulate antimigration in TMZ-treated U87MG cells. PG can enhance the antimigration effect of TMZ through suppression of metalloproteinase-2 and metalloproteinase-9 activities, ROS generation, and the NF-κB pathway and possibly provide a novel prospective strategy for treating malignant glioma.

ATIQCTPC targeting MMP-9: a key step to slowing primary tumor growth and inhibiting metastasis of lewis lung carcinoma in vivo

In this study we docked (6S)-3-acetyl-4-oxo-N-(2-(3,4,5,6-zetrahydroxytetrahydro-2H-pyran-2-carboxamido)ethyl)-4,6,7,12-tetrahydroindolo[2,3-a]quinolizine-6-carbo-xamide (ATIQCTPC) towards the active site of MMP-9, and showed that ATIQCTPC was able to effectively decrease the level of MMP-9 in the serum and the primary tumor of Lewis lung carcinoma (LLC) implanted C57BL/6 mice. As a MMP-9 inhibitor, ATIQCTPC inhibited the metastasis of LLC, and slowed the growth of the primary tumor of LLC implanted C57BL/6 in mice. The activities of ATIQCTPC to inhibit the ear edema and to decrease the serum levels of TNF-α and IL-8 of the mice treated with xylene were explored. The minimal effective dose of ATIQCTPC that can inhibit the primary tumour growth, prevent the metastasis of LLC and reduce the inflammatory response was 0.01 μmol/kg. The minimal effective dose of ATIQCTPC inhibiting tumour growth and metastasis was 100-fold lower than that of (S)-3-acetyl- 4-oxo-4,6,7,12-tetrahydroindolo[2,3-a]quinolizine-6-carboxylic acid (ATIQC, parent compound). The minimal effective dose of ATIQCTPC inhibiting inflammation was 110-fold lower than that of aspirin. These superiorities reflected the rationality of ATIQCTPC design. The safety of the therapy was explained by 1 μmol/kg of ATIQCTPC did not injure the kidney, the liver and the heart of the treated inflammation mice.

Synthesis and Evaluation of New Oxadiazole, Thiadiazole, and Triazole Derivatives as Potential Anticancer Agents Targeting MMP-9

Matrix metalloproteinases (MMPs) are important proteases involved in tumor progression including angiogenesis, tissue invasion, and migration. Therefore, MMPs have been reported as potential diagnostic and prognostic biomarkers in many types of cancer. New oxadiazole, thiadiazole, and triazole derivatives were synthesized and evaluated for their anticancer effects on A549 human lung adenocarcinoma and C6 rat glioma cell lines. In order to examine the relationship between their anticancer activity and MMP-9, the compounds were evaluated for their inhibitory effects on MMPs. N-(1,3-Benzodioxol-5-ylmethyl)-2-{[5-(((5,6,7,8-tetrahydronaphthalen-2-yl)oxy)methyl)-1,3,4-oxadiazol-2-yl]thio}acetamide (8) and N-(1,3-benzodioxol-5-ylmethyl)-2-[(5-phenyl-1,3,4-oxadiazol-2-yl)thio]acetamide (9) revealed promising cytotoxic effects on A549 and C6 cell lines similar to cisplatin without causing any toxicity towards NIH/3T3 mouse embryonic fibroblast cell line. Compounds 8 and 9 were also the most effective MMP-9 inhibitors in this series. Moreover, docking studies pointed out that compounds 8 and 9 had good affinity to the active site of the MMP-9 enzyme. The molecular docking and in vitro studies suggest that the MMP-9 inhibitory effects of compounds 8 and 9 may play an important role in lung adenocarcinoma and glioma treatment.