Calmodulin antagonist enhances DR5-mediated apoptotic signaling in TRA-8 resistant triple negative breast cancer cells

Antipsychotic drug trifluoperazine as a potential therapeutic agent against nasopharyngeal carcinoma

BACKGROUND

Trifluoperazine (TFP) is a typical antipsychotic primarily used to treat schizophrenia. In this study, we aimed to evaluate whether TFP can be used as a therapeutic agent against nasopharyngeal carcinoma (NPC) and identify its underlying molecular mechanisms.

METHODS

We used NPC-TW01, TW03, TW04, and BM to assess the anticancer effects of TFP by using cytotoxicity, wound healing, colony formation, and cell invasion assays. An in vivo animal study was conducted. RNA sequencing combined with Ingenuity Pathways Analysis was performed to identify the mechanism by which TFP influences NPC cells.

RESULTS

Our data revealed that TFP decreased NPC cell viability in a dose-dependent manner. The invasion and migration of NPC tumor cells were inhibited by TFP. An in vivo study also demonstrated the anticancer effects of TFP. RNA sequencing revealed several anticancer molecular mechanisms following TFP administration.

CONCLUSIONS

The antipsychotic drug TFP could be a potential therapeutic regimen for NPC treatment.

Understanding the Role of Dopamine in Cancer: Past, Present, and Future

Dopamine (DA, 3-hydroxytyramine) is member of the catecholamine family and is classically characterized according to its role in the central nervous system as a neurotransmitter. In recent decades, many novel and intriguing discoveries have been made about the peripheral expression of DA receptors (DRs) and the role of DA signaling in both normal and pathological processes. Drawing from decades of evidence suggesting a link between DA and cancer, the DA pathway (DAP) has recently emerged as a potential target in antitumor therapies. Due to the onerous, expensive, and frequently unsuccessful nature of drug development, the repurposing of dopaminergic drugs for cancer therapy has the potential to greatly benefit patients and drug developers alike. However, the lack of clear mechanistic data supporting the direct involvement of DRs and their downstream signaling components in cancer represents an ongoing challenge that has limited the translation of these drugs to the clinic. Despite this, the breadth of evidence linking DA to cancer and non-tumor cells in the tumor microenvironment (TME) justifies further inquiry into the potential applications of this treatment modality in cancer. Herein, we review the literature characterizing the interplay between the DA signaling axis and cancer, highlighting key findings, and then propose rational lines of investigation to follow.

Polymer Nanoparticles Overcome Drug Resistance by a Dual-Targeting Apoptotic Signaling Pathway in Breast Cancer

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) activating therapy has received wide attention due to its capacity to precisely induce cancer cell apoptosis. However, drug resistance and the poor pharmacokinetic properties of TRAIL protein are obstacles in TRAIL-based therapy for cancer. Herein, a strategy is developed to remotely control and specifically initiate TRAIL-mediated apoptotic signaling to promote TRAIL-resistant cancer cell apoptosis using near-infrared (NIR) light-absorbing conjugated polymer nanoparticles (CPNs). Upon 808 nm laser excitation, the promoter 70 kilodalton heat shock protein (HSP70) initiates transcription of the TRAIL gene in response to heat shock, thereby expressing TRAIL protein in breast cancer cells, which activates the TRAIL-mediated apoptosis signaling pathway. Simultaneously, the CPNs locally release W-7, which targets calmodulin (CaM) and further promotes caspase-8 cleavage and enhances cancer cell apoptosis. Both in vitro and in vivo results demonstrate that CPNs/W-7/pTRAIL produces an excellent synergistic therapeutic effect on breast cancer upon near-infrared light with low toxicity. Therefore, this work provides a strategy for overcoming drug resistance through dual-targeting TRAIL-mediated apoptotic signaling in breast cancer.

Drug repositioning: Using psychotropic drugs for the treatment of glioma

Psychotropic drugs can penetrate the blood-brain barrier and regulate the levels of neurotransmitters and neuromodulators such as γ-aminobutyric acid, glutamate, serotonin, dopamine, and norepinephrine in the brain, and thus influence neuronal activity. Neuronal activity in the tumor microenvironment can promote the growth and expansion of glioma. There is increasing evidence that in addition to their use in the treatment of mental disorders, antipsychotic, antidepressant, and mood-stabilizing drugs have clinical potential for cancer therapy. These drugs have been shown to inhibit the malignant progression of glioma by targeting signaling pathways related to cell proliferation, apoptosis, or invasion/migration or by increasing the sensitivity of glioma cells to conventional chemotherapy or radiotherapy. In this review, we summarize findings from preclinical and clinical studies investigating the use of antipsychotics, antidepressants, and mood stabilizers in the treatment of various types of cancer, with a focus on glioma; and discuss their presumed antitumor mechanisms. The existing evidence indicates that psychotropic drugs with established pharmacologic and safety profiles can be repurposed as anticancer agents, thus providing new options for the treatment of glioma.

Loperamide potentiates doxorubicin sensitivity in triple-negative breast cancer cells by targeting MDR1 and JNK and suppressing mTOR and Bcl-2: In vitro and molecular docking study

Multidrug resistance (MDR) is the leading cause of treatment failure in triple-negative breast cancer (TNBC) patients treated with doxorubicin (DXR). We aimed to investigate the potential of the antidiarrheal drug Loperamide (LPR) in sensitizing TNBC cells to DXR and elucidate the underlying molecular mechanisms. Therefore, we examined the effects of DXR alone or in combination with LPR on MDA-MD-231 cells viability using MTT assay, cell cycle, and apoptosis by flow cytometry, and the expression of the MDR-related genes (MDR1 and JNK1) and cell cycle/survival genes (p21, mTOR, and Bcl-2) by quantitative reverse transcription polymerase chain reaction. Results showed that adding LPR to DXR potentiated its antiproliferation effect and reduced its IC50 by twofolds compared with DXR alone. The value of the combination index of LPR/DXR was <1 indicating a synergistic effect. Combined DXR/LPR treatment also caused G1 arrest and potentiated apoptosis more than DXR-single treatment. At the molecular levels, LPR/DXR treatment downregulated the mRNA of MDR1 (1.35-folds), JNK1 (2.5-folds), mTOR (6.6-folds), Bcl-2 (9.5-folds); while upregulated p21 gene (8-folds) compared with DXR alone. Molecular docking analyses found LPR antagonizes MDR1 and JNK1 proteins, and hence supports the in vitro studies. In conclusion, the results confirmed the potential of LPR in sensitizing TNBCs to DXR by targeting MDR1 and JNK1 and suppressing Bcl-2 and mTOR genes, while upregulating the cell cycle inhibitor gene p21. Additionally, LPR could be repurposed to reduce the therapeutic doses of DXR as indicated by the dose reduction index (DRI) and subsequently decrease its side effects.

Modulation of calcium-binding proteins expression and cisplatin chemosensitivity by calcium chelation in human breast cancer MCF-7 cells

Cisplatin (CDDP) is currently one of the most effective FDA-approved treatments for breast cancer. Previous studies have shown that CDDP-induced cell death in human breast cancer (MCF-7) cells is associated with disruption of calcium homeostasis. However, whether the sensitivity of breast cancer cells to cisplatin is associated with dysregulation of the expression of calcium-binding proteins (CaBPs) remains unknown. In this study, we evaluated the effect of the intracellular calcium chelator (BAPTA-AM) on viability of MCF-7 cells in the presence of toxic and sub-toxic doses of cisplatin. Furthermore, this study assessed the expression of CaBPs, calmodulin, S100A8, and S100A14 in MCF-7 cells treated with cisplatin. Cell viability was determined using MTT-based in vitro toxicity assay. Intracellular calcium imaging was done using Fluo-4 AM, a cell-permeant fluorescent calcium indicator. Expression of CaBPs was tested using real-time quantitative PCR. Exposure of cells to increasing amounts of CDDP correlated with increasing fluorescence of the intracellular calcium indicator, Fluo-4 AM. Conversely, treating cells with cisplatin significantly decreased mRNA levels of calmodulin, S100A8, and S100A14. Treatment of the cells with calcium chelator, BAPTA-AM, significantly enhanced the cytotoxic effects of sub-toxic dose of cisplatin. Our results indicated a statistically significant negative correlation between calmodulin, S100A8, and S100A14 expression and sensitivity of breast cancer cells to a sub-toxic dose of cisplatin. We propose that modulating the activity of calcium-binding proteins, calmodulin, S100A8, and S100A14, could be used to increase cisplatin efficacy, lowering its treatment dosage while maintaining its chemotherapeutic value.

Calmodulin/CaMKII-γ mediates prosurvival capability in apicidin-persistent hepatocellular carcinoma cells via ERK1/2/CREB/c-fos signaling pathway

Calmodulin (CaM), a Ca²⁺ binding protein, plays a critical role in cancer initiation and progression through binding and activating numerous target proteins, including Ca²⁺ /calmodulin-dependent protein kinase (CaMK) family proteins. However, the mechanisms underlying the effects of CaM/CaMKs on the survival capability of liver cancer cells is unclear, and this study investigates this mechanism in apicidin-persistent HA22T cells. CaM level was upregulated, especially in the cytosol, in apicidin-persistent HA22T cells than in parental HA22T cells and was positively associated with cell proliferation and migration capacity of apicidin-persistent HA22T cells. Further, the expression of CaM-activated CaMKs-dependent signaling cascades, including CaMKK2, CaMKIV, CaMKII-γ, and p-CaMKII was observed in apicidin-persistent HA22T cells, which were transiently activated by mitogen-activated protein kinase oncogenic signaling, such as CREB, ERK1/2, and c-fos. Furthermore, a specific CaM inhibitor trifluoperazine reduced the levels of p-CREB, p-ERK1/2, and c-fos in apicidin-persistent HA22T cells than in parental HA22T cells. Additionally, inhibition of CaM also suppressed CaM-induced Bcl-XL (an antiapoptotic protein) expression in apicidin-persistent HA22T cells. Our finding emphasizes an essential role of CaM/CaMKs in augmentation of the survival capability of apicidin-persistent liver cancer cells and suggests that CaM inhibition significantly attenuates CaM-induced tumor growth and abrogates antiapoptotic function and also offers a promising therapeutic target for cancer treatment.

Repurposing of antipsychotic trifluoperazine for treating brain metastasis, lung metastasis and bone metastasis of melanoma by disrupting autophagy flux

Targeted therapies and immunotherapy have brought substantial benefits to patients with melanoma. However, brain metastases remain the biggest threat to the survival and quality of life of melanoma patients. One of the major challenges to an effective therapy is the inability of drugs to penetrate the blood-brain barrier (BBB). Anti-schizophrenic drugs can cross the BBB, and many of them have demonstrated anti-cancer effects. Repurposing existing drugs for new clinical indications is an alluring strategy for anticancer drug discovery. Herein, we applied this strategy and screened a small collection of existing anti-schizophrenic drugs to use as anti-melanoma agents. Among them, trifluoperazine dihydrochloride (TFP) exhibited promising potencies for suppressing the growth and metastasis of melanoma, both in vitro and in vivo. TFP obviously suppressed the viability of melanoma cells within the micromolar range and inhibited the growth of melanoma in the subcutaneous mice models. Notably, intraperitoneal (i.p.) administration of TFP (40 mg/kg/day) obviously inhibited the growth of intra-carotid-injection established melanoma brain metastasis and extended the survival of brain metastasis-bearing mice. Moreover, TFP significantly suppressed lung metastasis and bone metastasis of melanoma in preclinical metastasis models. Mechanistically, TFP caused G0/G1 cell cycle arrest and mitochondrial-dependent intrinsic apoptosis of melanoma cells. In addition, TFP treatment increased the expression of microtubule associated protein 1 light chain 3 beta-II (LC3B-II) and p62 in vitro, suggesting an inhibition of autophagic flux. TFP decreased LysoTracker Red uptake after treatment, indicating impaired acidification of lysosomes. Moreover, the colocalization of LC3 with lysosomal-associated membrane protein 1 (LAMP1), a lysosome marker, was also suppressed after TFP treatment, suggesting that TFP might block the fusion of autophagosomes with lysosomes, which led to autophagosome accumulation. Taken together, our data highlight the potential of repurposing TFP as a new adjuvant drug for treating melanoma patients with brain, lung, and bone metastases.

Calmodulin downregulation in conditional knockout HeLa cells inhibits cell migration

The study of calmodulin (CaM) functions in living cells has been tackled up to date using cell-permeant CaM inhibitors or interference-RNA methods. CaM inhibitors may lack specificity and the siRNA interference approach is challenging, as all three CaM genes expressing an identical protein in mammals have to be blocked. Therefore, we recently introduced a novel genetic system using CRISPR/Cas9-mediated gene deletion and conditional CaM expression to study the function of CaM in HeLa cells. Here, we describe the effect of CaM downregulation on the basal and epidermal growth factor (EGF)-dependent 2D- and 3D-migration in HeLa cells. CaM downregulation inhibited cell migration on a 2D-surface in the absence but not in the presence of EGF. In contrast, CaM downregulation led to inhibition of 3D-migration across a porous membrane both in the absence and presence of EGF. CaM downregulation decreased the expression of Rac1, Cdc42 and RhoA, all known to play crucial roles in cell migration. These results show that EGF-dependent 2D- and 3D-migration utilize distinct CaM-regulated systems and identify several essential migratory proteins directly or indirectly regulated by CaM.

Changes in Serum and Salivary Proteins in Canine Mammary Tumors

The aim of this study was to evaluate changes in serum and saliva proteomes in canine mammary tumors (CMT) using a high-throughput quantitative proteomic analysis in order to potentially discover possible biomarkers of this disease. Proteomes of paired serum and saliva samples from healthy controls (HC group, n = 5) and bitches with CMT (CMT group, n = 5) were analysed using a Tandem Mass Tags-based approach. Twenty-five dogs were used to validate serum albumin as a candidate biomarker in an independent sample set. The proteomic analysis quantified 379 and 730 proteins in serum and saliva, respectively. Of those, 35 proteins in serum and 49 in saliva were differentially represented. The verification of albumin in serum was in concordance with the proteomic data, showing lower levels in CMT when compared to the HC group. Some of the modulated proteins found in the present study such as haptoglobin or S100A4 have been related to CMT or human breast cancer previously, while others such as kallikrein-1 and immunoglobulin gamma-heavy chains A and D are described here for the first time. Our results indicate that saliva and serum proteomes can reflect physiopathological changes that occur in CMT in dogs and can be a potential source of biomarkers of the disease.

Antipsychotic Drug Trifluoperazine Suppresses Colorectal Cancer by Inducing G0/G1 Arrest and Apoptosis

Repurposing existing drugs for cancer treatment is an effective strategy. An approved antipsychotic drug, trifluoperazine (TFP), has been reported to have potential anticancer effects against several cancer types. Here, we investigated the effect and molecular mechanism of TFP in colorectal cancer (CRC). In vitro studies showed that TFP induced G0/G1 cell cycle arrest to dramatically inhibit CRC cell proliferation through downregulating cyclin-dependent kinase (CDK) 2, CDK4, cyclin D1, and cyclin E and upregulating p27. TFP also induced apoptosis, decreased mitochondrial membrane potential, and increased reactive oxygen species levels in CRC cells, indicating that TFP induced mitochondria-mediated intrinsic apoptosis. Importantly, TFP significantly suppressed tumor growth in two CRC subcutaneous tumor models without side effects. Interestingly, TFP treatment increased the expression levels of programmed death-1 ligand 1 (PD-L1) in CRC cells and programmed death-1 (PD-1) in tumor-infiltrating CD4+ and CD8+ T cells, implying that the combination of TFP with an immune checkpoint inhibitor, such as an anti-PD-L1 or anti-PD-1 antibody, might have synergistic anticancer effects. Taken together, our study signifies that TFP is a novel treatment strategy for CRC and indicates the potential for using the combination treatment of TFP and immune checkpoint blockade to increase antitumor efficiency.

Reactive oxygen species mediate the chemopreventive effects of syringin in breast cancer cells

BACKGROUND

Syringin (Syr), a phenylpropanoid glycoside extracted from Eleutherococcus senticosus, possesses various biological properties, including anticancer activities. However, the cytotoxicity effects of Syr on breast cancer have not yet been elucidated.

PURPOSE

In this study, we evaluated the anticancer potential of Syr on breast carcinoma and the mechanism involved.

STUDY DESIGN/METHODS

Non-tumorigenic (M10), tumorigenic (MCF7) and metastatic (MDA-MB-231) breast cancer cell lines as well as xenograft model were treated with Syr. Proliferation and cell cycle distribution were evaluated using the MTT, the colony formation assay and flow cytometry. The expression levels of cytotoxicity-related proteins were detected by Western blot.

RESULTS

Here, we found that colony formation inhibition, cell cycle arrest in the G2/M phase, down-regulation of X-linked inhibitor of apoptosis protein (XIAP), cleaved poly (ADP-ribose) polymerase (PARP) and caspase-3/9 activation were observed in MCF7 and MDA-MB-231 cells treated with Syr. Moreover, pretreatment with a pan-caspase inhibitor (Z-DEVD-FMK) inhibited Syr-induced apoptosis. In addition, treatment with Syr also increased the production of reactive oxygen species (ROS). However, the antioxidant N-acetyl-cysteine (NAC) reversed the ROS levels and rescued the apoptotic changes. Meanwhile, Syr inhibited the growth of breast cancer xenograft models and dramatically decreased tumor volume without any obvious body weight loss in vivo.

CONCLUSION

Our findings suggest that Syr induces oxidative stress to suppress the proliferation of breast cancer and thus might be an effective therapeutic agent to treat breast cancer.