CAI inhibits the growth of small cell lung cancer cells

Carboxyamidotriazole alleviates pannus formation and cartilage erosion in rats with adjuvant arthritis

Carboxyamidotriazole (CAI) was initially considered a non-cytotoxic anticancer agent. However, recently, pronounced anti-inflammatory properties of CAI have been reported. Rheumatoid arthritis (RA) is an autoimmune inflammatory disease characterized by aberrant activation of signaling pathways. Therefore, this study explored the therapeutic effects and potential mechanism of action of CAI on RA in the adjuvant arthritis (AA) model. The results showed that CAI reduced the severity of arthritis in AA rats as demonstrated by inhibited hind paw swelling, reduced body weight, and decreased infiltration of joint pathological inflammatory cells. Importantly, pathological scoring of new blood vessels and immunohistochemical assays revealed that CAI inhibited pannus formation. CAI decreased the expression of pro-angiogenic growth factors, such as vascular epidermal growth factor, basic fibroblast growth factor, and metalloproteinases (MMPs), namely, MMP-1 and MMP-3 in the synovium of AA rats. Furthermore, CAI significantly reduced the increased levels of phosphorylated p38, c-Jun N-terminal kinase (JNK)1/2, and extracellular signal-regulated kinase (ERK)1/2 proteins in AA rats. In addition, the proliferation of fibroblast-like synoviocytes (FLS) was downregulated by CAI both in vivo and in vitro. In conclusion, this investigation illustrates the therapeutic effect of CAI on synovitis and erosion of articular cartilage in RA. Furthermore, the mechanism might involve inhibition of aberrantly activated mitogen-activated protein kinase signaling, as well as a decrease in pro-angiogenic factors, MMP expression, and FLS proliferation.

A Recent Overview of 1,2,3-Triazole-Containing Hybrids as Novel Antifungal Agents: Focusing on Synthesis, Mechanism of Action, and Structure-Activity Relationship (SAR)

A pharmacophore system has been found as 1,2,3-triazole, a five-membered heterocycle ring with nitrogen heteroatoms. These heterocyclic compounds can be produced using azide-alkyne cycloaddition processes catalyzed by ruthenium or copper. The bioactive compounds demonstrated antitubercular, antibacterial, anti-inflammatory, anticancer, antioxidant, antiviral, and antidiabetic properties. This heterocycle molecule, in particular, with one or more 1,2,3-triazole cores has been found to have the most powerful antifungal effects. The goal of this review is to highlight recent developments in the synthesis and structure-activity relationship (SAR) investigation of this prospective fungicidal chemical. Also there have been explained drugs and mechanism of action of a triazole compound with antifungal activity. This review will be useful in a variety of fields, including medicinal chemistry, organic chemistry, mycology, and pharmacology.

Development of Store-Operated Calcium Entry-Targeted Compounds in Cancer

Store-operated Ca²⁺ entry (SOCE) is the major pathway of Ca²⁺ entry in mammalian cells, and regulates a variety of cellular functions including proliferation, motility, apoptosis, and death. Accumulating evidence has indicated that augmented SOCE is related to the generation and development of cancer, including tumor formation, proliferation, angiogenesis, metastasis, and antitumor immunity. Therefore, the development of compounds targeting SOCE has been proposed as a potential and effective strategy for use in cancer therapy. In this review, we summarize the current research on SOCE inhibitors and blockers, discuss their effects and possible mechanisms of action in cancer therapy, and induce a new perspective on the treatment of cancer.

Carboxyamidotriazole exerts anti-inflammatory activity in lipopolysaccharide-induced RAW264.7 macrophages by inhibiting NF-κB and MAPKs pathways

Carboxyamidotriazole (CAI), originally developed as a non-cytotoxic anti-cancer drug, was shown to have anti-inflammatory activity according to recent studies in a number of animal models of inflammation. However, its mechanism of action has not been characterized. Therefore, the present study was performed to identify the anti-inflammatory action of CAI in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages and to identify the signal transduction pathways involved. The in vitro results revealed that CAI had no direct effect on the activity of cyclooxygenase (COX), suggesting a different anti-inflammatory mechanism compared with that of COX-inhibiting non-steroidal anti-inflammatory drugs. Further investigation in RAW264.7 macrophages revealed that CAI decreased the production of nitric oxide via decreasing the LPS-stimulated expression of inducible nitric oxide synthase, and downregulated both mRNA and protein expression levels of the cytokines tumor necrosis factor-α, interleukin (IL)-1β, and IL-6. CAI also significantly reduced the increased DNA-binding activity of nuclear factor (NF)-κB induced by LPS stimulation. With respect to the mechanisms involved on NF-κB activity, CAI exhibited suppression of the phosphorylation and degradation of the inhibitor of nuclear factor-κBα (IκB), and decreased the phosphorylation levels of the p65 subunit and its subsequent nuclear translocation. In addition, CAI significantly decreased the phosphorylated forms of p38, JNK and ERK, which were increased following LPS stimulation, while the total expression levels of p38, JNK and ERK remained unaltered. The results in the present study indicate that CAI alleviates the inflammatory responses of RAW 264.7 macrophages in response to LPS stimulation via attenuating the activation of NF-κB and MAPK signaling pathways and decreasing the levels of pro-inflammatory mediators. This offers a novel perspective for understanding the anti-inflammatory mechanism of CAI and suggests its potential use as a therapeutic treatment in inflammatory diseases with excessive macrophage activation.

Carboxyamidotriazole combined with IDO1-Kyn-AhR pathway inhibitors profoundly enhances cancer immunotherapy

Background

Cancer immunotherapy has generated significant excitement, mainly as a result of the development of immune checkpoint inhibitors. The blockade of PD-1 or its ligand with antibodies has resulted in impressive clinical efficacy. However, a subset of patients does not respond to biologic therapeutics, and another subset suffers from severe immune-related adverse events in certain cases. The modulation of the immune system with small molecules might yield surprising benefits.

Methods

CD8⁺ cells were obtained through a magnetic cell sorting system (MACS), and their capabilities for IFN-γ release and PD-1 expression were analyzed. The in vitro effects of drugs were studied in a coculture system of tumor cells and activated CD8⁺ cells. We further isolated the primary tumor cells in tumor-bearing mice treated with CAI, DMF, 1-MT or a combination (CAI and DMF/CAI and 1-MT) and analyzed the percentages of CD8⁺ T cells and PD-1⁺CD8⁺ T cells among TILs. The selective anti-tumor immune reactions of the two drug combinations were confirmed in a coculture system consisting of B16-OVA cells and OVA-specific CTLs derived from OT-1 transgenic mice. The anti-tumor effects of the single drugs or combined therapies were assessed according to their capability to slow tumor growth and extend the life span of tumor-bearing mice, and they were compared with the effects of PD-1 antibody.

Results

CAI increased IFN-γ release from activated T cells, which might strengthen the anti-proliferative and anti-metastatic effects on cancer cells. However, CAI also stimulated IDO1-Kyn metabolic circuitry in the tumor microenvironment and facilitated tumor cell immune evasion. Combining CAI with 1-MT or DMF disrupted PD-1 expression and promoted IFN-γ production in CD8⁺ T cells, and it also increased T lymphocyte infiltration in the tumor microenvironment, inhibited tumor growth and prolonged the life spans of tumor-bearing mice.

Conclusion

Inhibitors of the IDO1-Kyn-AhR pathway could abolish the negative effects of CAI on CD8⁺ T cells and result in complementary and beneficial anti-tumor immune effects. The combination of CAI with 1-MT or DMF greatly augmented the ability of CD8⁺ T cells to kill malignant cells and showed a strong anti-cancer capability that was superior to that of either of the single agents was is comparable with that of anti-PD-1 antibody. The combinations of small molecules utilized in this study may serve as valuable new immunotherapy strategies for cancer treatment.

Electronic supplementary material

The online version of this article (10.1186/s40425-019-0725-7) contains supplementary material, which is available to authorized users.

Inhibition of store-operated channels by carboxyamidotriazole sensitizes ovarian carcinoma cells to anti-BclxL strategies through Mcl-1 down-regulation

The anti-apoptotic proteins Bcl-xL and Mcl-1 have been identified to play a pivotal role in apoptosis resistance in ovarian cancer and constitute key targets for innovative therapeutic strategies. Although BH3-mimetics (i.e. ABT-737) potently inhibit Bcl-xL activity, targeting Mcl-1 remains a hurdle to the success of these strategies. Calcium signaling is profoundly remodeled during carcinogenesis and was reported to activate the signaling pathway controlling Mcl-1 expression. In this context, we investigated the effect of carboxyamidotriazole (CAI), a calcium channel inhibitor used in clinical trials, on Mcl-1 expression. CAI had an anti-proliferative effect on ovarian carcinoma cell lines and strongly down-regulated Mcl-1 expression. It inhibited store-operated calcium entry (SOCE) and Mcl-1 translation through mTORC1 deactivation. Moreover, it sensitized ovarian carcinoma cells to anti-Bcl-xL strategies as their combination elicited massive apoptosis. Its effect on mTORC1 and Mcl-1 was mimicked by the potent SOCE inhibitor, YM58483, which also triggered apoptosis when combined with ABT-737. As a whole, this study suggests that CAI sensitizes to anti-Bcl-xL strategies via its action on Mcl-1 translation and that modulation of SOCE could extend the therapeutic arsenal for treatment of ovarian carcinoma.

Endothelial Ca2+ Signaling and the Resistance to Anticancer Treatments: Partners in Crime

Intracellular Ca²⁺ signaling drives angiogenesis and vasculogenesis by stimulating proliferation, migration, and tube formation in both vascular endothelial cells and endothelial colony forming cells (ECFCs), which represent the only endothelial precursor truly belonging to the endothelial phenotype. In addition, local Ca²⁺ signals at the endoplasmic reticulum (ER)-mitochondria interface regulate endothelial cell fate by stimulating survival or apoptosis depending on the extent of the mitochondrial Ca²⁺ increase. The present article aims at describing how remodeling of the endothelial Ca²⁺ toolkit contributes to establish intrinsic or acquired resistance to standard anti-cancer therapies. The endothelial Ca²⁺ toolkit undergoes a major alteration in tumor endothelial cells and tumor-associated ECFCs. These include changes in TRPV4 expression and increase in the expression of P2X7 receptors, Piezo2, Stim1, Orai1, TRPC1, TRPC5, Connexin 40 and dysregulation of the ER Ca²⁺ handling machinery. Additionally, remodeling of the endothelial Ca²⁺ toolkit could involve nicotinic acetylcholine receptors, gasotransmitters-gated channels, two-pore channels and Na⁺/H⁺ exchanger. Targeting the endothelial Ca²⁺ toolkit could represent an alternative adjuvant therapy to circumvent patients' resistance to current anti-cancer treatments.

Targeting calcium signaling in cancer therapy

The intracellular calcium ions (Ca2+) act as second messenger to regulate gene transcription, cell proliferation, migration and death. Accumulating evidences have demonstrated that intracellular Ca2+ homeostasis is altered in cancer cells and the alteration is involved in tumor initiation, angiogenesis, progression and metastasis. Targeting derailed Ca2+ signaling for cancer therapy has become an emerging research area. This review summarizes some important Ca2+ channels, transporters and Ca2+-ATPases, which have been reported to be altered in human cancer patients. It discusses the current research effort toward evaluation of the blockers, inhibitors or regulators for Ca2+ channels/transporters or Ca2+-ATPase pumps as anti-cancer drugs. This review is also aimed to stimulate interest in, and support for research into the understanding of cellular mechanisms underlying the regulation of Ca2+ signaling in different cancer cells, and to search for novel therapies to cure these malignancies by targeting Ca2+ channels or transporters.

Activation of NALP1 inflammasomes in rats with adjuvant arthritis; a novel therapeutic target of carboxyamidotriazole in a model of rheumatoid arthritis

BACKGROUND AND PURPOSE

Pro-inflammatory cytokines are important in rheumatoid arthritis (RA) and their production is mainly regulated by NF-κB and inflammasomes. Carboxyamidotriazole (CAI) exhibits potent anti-inflammatory activities by decreasing cytokines. Here, we have investigated NACHT, LRR and PYD domains-containing protein (NALP) inflammasomes in a rat model of RA and explored the therapeutic effects of CAI in this model and the involvement of NF-κB and inflammasomes in the actions of CAI.

EXPERIMENTAL APPROACH

The anti-arthritic effects of CAI were assessed in the adjuvant arthritis (AA) model in rats, using radiological and histological techniques. NALP1 and NALP3 inflammasomes, NF-κB pathway and pro-inflammatory cytokines levels were measured with Western blots, immunohistochemistry and ELISA.

KEY RESULTS

CAI decreased the arthritis index, improved radiological and histological changes, and reduced synovial IL-1β, IL-6, IL-18 and TNF-α levels in rats with AA. Compared with normal rats, the 70 kDa NALP1 isoform was up-regulated, NALP3 was down-regulated, and levels of the 165 kDa NALP1 isoform and the adaptor protein ASC were unchanged in synovial tissue from AA rats. CAI reduced the 70 kDa NALP1 isoform and restored NALP3 levels in AA rats; CAI inhibited caspase-1 activation in AA synovial tissue, but not its enzymic activity in vitro. In addition, CAI reduced expression of p65 NF-κB subunit and IκBα phosphorylation and degradation in AA rats.

CONCLUSION AND IMPLICATIONS

NALP1 inflammasomes were activated in synovial tissues from AA rats and appeared to be a novel therapeutic target for RA. CAI could have therapeutic value in RA by inhibiting activation of NF-κB and NALP1 inflammasomes and by decreasing pro-inflammatory cytokines.

Rational design, synthesis and anti-proliferative evaluation of novel 1,4-benzoxazine-[1,2,3]triazole hybrids

A series of novel 1,2,3-triazole-1,4-benzoxazine hybrids 5a-n were efficiently synthesized employing click chemistry approach and evaluated for anti-proliferative activity against four cancer cell lines such as HeLa (cervical), MIAPACA (pancreatic), MDA-MB-231 (breast) and IMR32 (neuroblastoma). Compounds 5n and 5g exhibited promising anti-proliferative activity with GI50 values ranging from 1.2 to 2.5 μM and 0.1-1.1 μM respectively against all cell lines, like HeLa, MDA-MB-231, MIAPACA and IMR32, while compound 5l showed significant activity against MDA-MB-231 and IMR32 with GI50 values ranging from 1.1 and 1.4 μM. This is the first report on the synthesis and in vitro anti-proliferative evaluation of 1,2,3-triazole-1,4-benzoxazine hybrids.

Synthesis and anti-protozoal activity of novel dihydropyrrolo[3,4-d][1,2,3]triazoles

1,2,4-Oxadiazole and 1,2,3-triazole containing heterocyclic compounds continue to gain interest in synthesis of chemical entities and exhibit various biological activities as anti-protozoal and anti-cancer agents. By using the principle of bioisosterism, a series of novel oxadiazolyl pyrrolo triazole diones; namely, (3aS,6aR)-1-((3-(4-substituted phenyl)-1,2,4-oxadiazol-5-yl)methyl)-5-phenyl-1,6a-dihydropyrrolo[3,4-d][1,2,3] triazole-4,6(3aH,5H)-diones (5a-k) was designed and synthesized by the 1,3-dipolar cycloaddition reaction of novel 5-azidomethyl 3-aryl substituted 1,2,4-oxadiazoles (4a-k) with N-phenyl maleimide. The structures of all the cycloadducts were elucidated by means of spectroscopic methods and physical characteristics. The in vitro anti-protozoal and cytotoxic activities of these novel heterocyclic compounds were investigated.

Effects of carboxyamidotriazole on in vitro models of imatinib-resistant chronic myeloid leukemia

Although imatinib mesylate (IM) has revolutionized the treatment of chronic myeloid leukemia (CML), some patients develop resistance with progression of leukemia. Alternative or additional targeting of signaling pathways deregulated in bcr-abl-driven CML cells may provide a feasible option for improving clinical response and overcoming resistance. In this study, we show that carboxyamidotriazole (CAI), an orally bioavailable calcium influx and signal transduction inhibitor, is equally effective in inhibiting the proliferation and bcr-abl dependent- and independent-signaling pathways in imatinib-resistant CML cells. CAI inhibits phosphorylation of cellular proteins including STAT5 and CrkL at concentrations that induce apoptosis in IM-resistant CML cells. The combination of imatinib and CAI also down-regulated bcr-abl protein levels. Since CAI is already available for clinical use, these results suggest that it may be an effective addition to the armamentarium of drugs for the treatment of CML.

Anti-inflammatory and analgesic potency of carboxyamidotriazole, a tumorostatic agent

Carboxyamidotriazole (CAI) is a calcium influx inhibitor that is undergoing clinical trials for the treatment of various human cancers following the identification of its antiproliferative and antimetastatic activities. The exact mechanism of its action is not clearly understood, and whether it has other functions besides the established antitumor activity has not been reported either. In the present study, we demonstrate for the first time that CAI possesses anti-inflammatory and analgesic activities using a variety of animal models, including croton oil-induced ear edema, cotton-induced granuloma, rat adjuvant-induced arthritis, acetic acid-induced writhing, and the formalin test. We also show that CAI significantly inhibits local vascular permeability stimulated by vascular endothelial growth factor or histamine and decreases tumor necrosis factor-alpha and interleukin-1beta levels at the site of inflammation and in serums, which may contribute to the anti-inflammatory effect. These data suggest that CAI is a promising anti-inflammatory and analgesic agent, and they provide new insight into the biological activity of the drug.

Phase III randomized, double-blind study of maintenance CAI or placebo in patients with advanced non-small cell lung cancer (NSCLC) after completion of initial therapy (NCCTG 97-24-51)

PURPOSE

This study assessed whether maintenance therapy with carboxyaminoimidazole (CAI), compared to placebo, prolonged overall survival in stage IIIB/IV NSCLC patients who had tumour regression or stable disease after treatment with one chemotherapy regimen.

METHODS

After completion of chemotherapy, patients were randomized to receive daily oral CAI at 250mg or placebo. Treatment continued until patient refusal, disease progression or unacceptable adverse event (AE). Quality of life (QOL) was assessed by UNISCALE and Functional Assessment of Cancer Therapy for Lung Cancer (FACT-L).

RESULTS

Registration was halted early for slow accrual (targeted 360, randomized 186: 94 CAI, 92 placebo). All patients were off active treatment at time of analyses. Non-haematologic AEs (primarily grade 1, 2) observed significantly more often in the CAI group included fatigue (54.5% versus 29.3%), anorexia (31.1% versus 13.0%), nausea (62.2% versus 30.4%), vomiting (32.2% versus 14.1%), neurosensory (60.0% versus 44.6%) and ataxia (33.3% versus 16.3%). Patients discontinued treatment for AEs, death on study or refusal more often in the CAI group (36.0% versus 8.7%, p<0.0001). No significant differences in survival or time to progression were observed (median: CAI versus placebo: 11.4 months versus 10.5 months, log rank p=0.54; 2.8 months versus 2.4 months, log rank p=0.50). More patients receiving CAI reported a clinically significant (10-point) decline in QOL particularly on the functional (58% versus 37%, p=0.05) construct of FACT-L and UNISCALE (72% versus 51%, p=0.04).

CONCLUSION

The addition of CAI following chemotherapy does not provide clinical benefit or improvement in QOL over placebo in advanced NSCLC.

Carboxyamido-triazole inhibits proliferation of human breast cancer cells via G(2)/M cell cycle arrest and apoptosis

Carboxyamido-triazole (CAI), a voltage-independent calcium channel inhibitor, has been shown to be able to induce growth inhibition and apoptosis in cancer cells. In the present study, we demonstrate that CAI significantly inhibits proliferation of cultured MCF-7 human breast cancer cells in a dose-dependent manner with an IC(50) of approximately 26 microM. Reduced proliferation of MCF-7 cells in the presence of CAI correlated with accumulation of cells in G(2)/M phase and induction of apoptosis. A treatment of MCF-7 cells with 30 microM CAI caused a time-dependent decrease in the levels of proteins that regulate G(2)/M progression, including Cdk1, Cyclin B1, and Cdc25C. A simultaneous increase in the expression of p21 protein was observed. We also demonstrated a concurrent decrease of the mitochondrial membrane potential (DeltaPsi(m)), and down-regulation of anti-apoptotic protein Bcl-2. In conclusion, it seems reasonable to hypothesize that the antitumor effect of CAI in MCF-7 cells is based on G(2)/M cell cycle arrest and inducing apoptosis.

Gastrin-releasing peptide (GRP) induces angiogenesis and the specific GRP blocker 77427 inhibits tumor growth in vitro and in vivo

Angiogenesis is becoming a major target for antitumor therapies, and identifying new angiogenic factors and their specific inhibitors may provide new avenues for tumor management. Here we identify gastrin-releasing peptide (GRP) as a new angiogenic molecule that is secreted by tumors and acts directly upon GRP receptors in the endothelial cells. Addition of GRP increases endothelial cell migration and cord formation in vitro, and induces angiogenesis in an in vivo assay. We have recently identified a small molecule GRP blocker, compound 77427. This inhibitor significantly reduced endothelial cell cord formation in vitro and angiogenesis in vivo. Conversely, when applied to VEGF-induced angiogenesis, the small molecule did not have any effect, demonstrating its specificity. Furthermore, this GRP blocker was able to reduce lung tumor cell growth in vitro as demonstrated by MTT and clonogenic assays. When applied to a xenograft model with lung cancer cells, compound 77427 reduced tumor volume to undetectable sizes, although when the treatment was suspended, tumors began to grow again at normal rates. Our collective observations indicate that GRP is a new angiogenic peptide and that its inhibition offers an attractive tool to reduce tumor burden.