Thioridazine enhances sensitivity to carboplatin in human head and neck cancer cells through downregulation of c-FLIP and Mcl-1 expression

Butein inhibits oral squamous cell carcinoma growth via promoting MCL-1 ubiquitination

Oral squamous cell carcinoma (OSCC) is the most common malignant head and neck carcinoma type. Myeloid cell leukemia-1 (MCL-1), an anti-apoptotic BCL-1 protein, has been verified to be among the most highly upregulated pathologic proteins in human cancers linked to tumor relapse, poor prognosis and therapeutic resistance. Herein, therapeutic targeting MCL-1 is an attractive focus for cancer treatment. The present study found that butein, a potential phytochemical compound, exerted profound antitumor effects on OSCC cells. Butein treatment significantly inhibited cell viability, proliferation capacity and colony formation ability, and activated cell apoptotic process. Further potential mechanism investigation showed that promoting MCL-1 ubiquitination and degradation is the major reason for butein-mediated OSCC cell cytotoxicity. Our results uncovered that butein could facilitate E3 ligase FBW7 combined with MCL-1, which contributed to an increase in the ubiquitination of MCL-1 Ub-K48 and degradation. The results of both in vitro cell experiments and in vivo xenograft models imply a critical antitumor function of butein with the well-tolerated feature, and it might be an attractive and promising agent for OSCC treatment.

Phenothiazines: Nrf2 activation and antioxidant effects

Phenothiazines (PTZs) are an emerging group of molecules showing effectiveness toward redox signaling and reduction of oxidative injury to cells, via the activation on Kelch-like ECH-associated protein 1/nuclear factor erythroid 2-related factor 2 (Nrf2). Although several electrophilic and indirect Nrf2 activators have been reported, the risk of "off-target" effect due to the complexity of their molecular mechanisms of action, has aroused research interest toward non-electrophilic and direct modulators of Nrf2 pathway, such as PTZs. This review represents the first overview on the roles of PTZs as non-electrophilic Nrf2 activator and free radical scavengers, as well as on their potential therapeutic effects in oxidative stress-mediated diseases. Here, we provide a collective and comprehensive information on the PTZs ability to scavenge free radicals and activate the Nrf2 signaling pathway, with the aim to broaden the knowledge of their therapeutic potentials and to stimulate innovative research ideas.

Targeting Prostate Cancer, the 'Tousled Way'

Androgen deprivation therapy (ADT) has been the mainstay of prostate cancer (PCa) treatment, with success in developing more effective inhibitors of androgen synthesis and antiandrogens in clinical practice. However, hormone deprivation and AR ablation have caused an increase in ADT-insensitive PCas associated with a poor prognosis. Resistance to ADT arises through various mechanisms, and most castration-resistant PCas still rely on the androgen axis, while others become truly androgen receptor (AR)-independent. Our research identified the human tousled-like kinase 1 (TLK1) as a crucial early mediator of PCa cell adaptation to ADT, promoting androgen-independent growth, inhibiting apoptosis, and facilitating cell motility and metastasis. Although explicit, the growing role of TLK1 biology in PCa has remained underrepresented and elusive. In this review, we aim to highlight the diverse functions of TLK1 in PCa, shed light on the molecular mechanisms underlying the transition from androgen-sensitive (AS) to an androgen-insensitive (AI) disease mediated by TLK1, and explore potential strategies to counteract this process. Targeting TLK1 and its associated signaling could prevent PCa progression to the incurable metastatic castration-resistant PCa (mCRPC) stage and provide a promising approach to treating PCa.

Treatment of cancer with antipsychotic medications: Pushing the boundaries of schizophrenia and cancer

Over a century ago, the phenothiazine dye, methylene blue, was discovered to have both antipsychotic and anti-cancer effects. In the 20th-century, the first phenothiazine antipsychotic, chlorpromazine, was found to inhibit cancer. During the years of elucidating the pharmacology of the phenothiazines, reserpine, an antipsychotic with a long historical background, was likewise discovered to have anti-cancer properties. Research on the effects of antipsychotics on cancer continued slowly until the 21st century when efforts to repurpose antipsychotics for cancer treatment accelerated. This review examines the history of these developments, and identifies which antipsychotics might treat cancer, and which cancers might be treated by antipsychotics. The review also describes the molecular mechanisms through which antipsychotics may inhibit cancer. Although the overlap of molecular pathways between schizophrenia and cancer have been known or suspected for many years, no comprehensive review of the subject has appeared in the psychiatric literature to assess the significance of these similarities. This review fills that gap and discusses what, if any, significance the similarities have regarding the etiology of schizophrenia.

The Therapeutic Potential of Carnosine as an Antidote against Drug-Induced Cardiotoxicity and Neurotoxicity: Focus on Nrf2 Pathway

Different drug classes such as antineoplastic drugs (anthracyclines, cyclophosphamide, 5-fluorouracil, taxanes, tyrosine kinase inhibitors), antiretroviral drugs, antipsychotic, and immunosuppressant drugs are known to induce cardiotoxic and neurotoxic effects. Recent studies have demonstrated that the impairment of the nuclear factor erythroid 2–related factor 2 (Nrf2) pathway is a primary event in the pathophysiology of drug-induced cardiotoxicity and neurotoxicity. The Nrf2 pathway regulates the expression of different genes whose products are involved in antioxidant and inflammatory responses and the detoxification of toxic species. Cardiotoxic drugs, such as the anthracycline doxorubicin, or neurotoxic drugs, such as paclitaxel, suppress or impair the Nrf2 pathway, whereas the rescue of this pathway counteracts both the oxidative stress and inflammation that are related to drug-induced cardiotoxicity and neurotoxicity. Therefore Nrf2 represents a novel pharmacological target to develop new antidotes in the field of clinical toxicology. Interestingly, carnosine (β-alanyl-l-histidine), an endogenous dipeptide that is characterized by strong antioxidant, anti-inflammatory, and neuroprotective properties is able to rescue/activate the Nrf2 pathway, as demonstrated by different preclinical studies and preliminary clinical evidence. Starting from these new data, in the present review, we examined the evidence on the therapeutic potential of carnosine as an endogenous antidote that is able to rescue the Nrf2 pathway and then counteract drug-induced cardiotoxicity and neurotoxicity.

Myeloid cell leukemia-1 expression in cancers of the oral cavity: a scoping review

Background

B cell lymphoma-2 (Bcl-2) family members play important roles in cell survival as well as cell death. The role of myeloid cell leukemia-1 (Mcl-1), an important member of the Bcl-2 family, is well established in hematopoietic malignancies. However, the association between Mcl-1 and oral cavity, cancers is not clearly defined.

Methods

A scoping review was conducted until June 30, 2021, using four major databases, PubMed, Scopus, Web of Science, and Embase. Medical subject headings keywords for Mcl-1, along with its other identifiers, and head and neck cancers (only oral cavity tumors) were used to evaluate the expression, function, molecular association, and therapeutic approach of Mcl-1 in oral cavity cancers and precancers.

Findings

Mcl-1 expression was associated with the progression of oral cavity cancers. The molecular mechanism and pathways of Mcl-1 in oral cavity cancers established via experimental results have been highlighted in this review. Moreover, the various synthetic and naturally derived therapeutic agents targeting Mcl-1 have been documented.

Novelty/Improvement

Based on our present review, Mcl-1 appears to be an effective anticancer target that can be used in the therapeutic management of oral cancers.

Bayesian hierarchical lasso Cox model: A 9-gene prognostic signature for overall survival in gastric cancer in an Asian population

Objective

Gastric cancer (GC) is one of the most common tumour diseases worldwide and has poor survival, especially in the Asian population. Exploration based on biomarkers would be efficient for better diagnosis, prediction, and targeted therapy.

Methods

Expression profiles were downloaded from the Gene Expression Omnibus (GEO) database. Survival-related genes were identified by gene set enrichment analysis (GSEA) and univariate Cox. Then, we applied a Bayesian hierarchical lasso Cox model for prognostic signature screening. Protein-protein interaction and Spearman analysis were performed. Kaplan–Meier and receiver operating characteristic (ROC) curve analysis were applied to evaluate the prediction performance. Multivariate Cox regression was used to identify prognostic factors, and a prognostic nomogram was constructed for clinical application.

Results

With the Bayesian lasso Cox model, a 9-gene signature included TNFRSF11A, NMNAT1, EIF5A, NOTCH3, TOR2A, E2F8, PSMA5, TPMT, and KIF11 was established to predict overall survival in GC. Protein-protein interaction analysis indicated that E2F8 was likely related to KIF11. Kaplan-Meier analysis showed a significant difference between the high-risk and low-risk groups (P<0.001). Multivariate analysis demonstrated that the 9-gene signature was an independent predictor (HR = 2.609, 95% CI 2.017–3.370), and the C-index of the integrative model reached 0.75. Function enrichment analysis for different risk groups revealed the most significant enrichment pathway/term, including pyrimidine metabolism and respiratory electron transport chain.

Conclusion

Our findings suggested that a novel prognostic model based on a 9-gene signature was developed to predict GC patients in high-risk and improve prediction performance. We hope our model could provide a reference for risk classification and clinical decision-making.

The Mechanisms of Current Platinum Anticancer Drug Resistance in the Glioma

Gliomas are the most common and malignant primary tumors of the central nervous system (CNS). Glioblastomas are the most malignant and aggressive form of primary brain tumors and account for the majority of brain tumor-related deaths. The current standard treatment for gliomas is surgical resection supplemented by postoperative chemotherapy. Platinum drugs are a class of chemotherapeutic drugs that affect the cell cycle, and the main site of action is the DNA of cells, which are common chemotherapeutic drugs in clinical practice. Chemotherapy with platinum drugs such as cisplatin, carboplatin, oxaliplatin, or a combination thereof is used to treat a variety of tumors. However, the results of gliomas chemotherapy are unsatisfactory, and resistance to platinum drugs is one of the important reasons. The resistance of gliomas to platinum drugs is the result of a combination of influencing factors. Decreased intracellular drug concentration, enhanced function of cell processing active products, enhanced repair ability of cellular DNA damage, and blockage of related apoptosis pathways play an important role in it. It is known that the pathogenic properties of glioma cells and the response of glioma towards platinum-based drugs are strongly influenced by non-coding RNAs, particularly, by microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). miRNAs and lncRNAs control drug sensitivity and the development of tumor resistance towards platinum drugs. This mini-review summarizes the resistance mechanisms of gliomas to platinum drugs, as well as molecules and therapies that can improve the sensitivity of gliomas to platinum drugs.

Repurposing Antipsychotics for Cancer Treatment

Cancer is a leading cause of death worldwide, with approximately 19 million new cases each year. Lately, several novel chemotherapeutic drugs have been introduced, efficiently inhibiting tumor growth and proliferation. However, developing a new drug is a time- and money-consuming process, requiring around 1 billion dollars and nearly ten years, with only a minority of the initially effective anti-cancer drugs experimentally finally being efficient in human clinical trials. Drug repurposing for cancer treatment is an optimal alternative as the safety of these drugs has been previously tested, and thus, in case of successful preclinical studies, can be introduced faster and with a lower cost into phase 3 clinical trials. Antipsychotic drugs are associated with anti-cancer properties and, lately, there has been an increasing interest in their role in cancer treatment. In the present review, we discussed in detail the in-vitro and in-vivo properties of the most common typical and atypical antipsychotics, along with their mechanism of action.

EF24 exerts cytotoxicity against NSCLC via inducing ROS accumulation

Background

The role of Diphenyldifluoroketone (EF24), a synthetic analogue of curcumin with noteworthy antitumor potential, remains unclear in non-small cell lung cancer (NSCLC). Herein, the inhibitory effect of EF24 on NSCLC and its mechanism were studied.

Methods

Cytotoxicity was measured by MTT assay, colony formation assay and xenograft model. Cell apoptosis and reactive oxygen species (ROS) level were quantified by flow cytometer. Protein level was detected by western blot assay. Mitochondria and autophagosomes were observed using transmission electron microscope and confocal microscopy.

Results

In-vitro, EF24 significantly induced proliferation inhibition, apoptosis, mitochondrial fission and autophagy of NSCLC cell lines. These cytotoxic effects were significantly attenuated by two reactive oxygen species (ROS) scavengers, indicating its anti-cancer effects largely depend on ROS accumulation. In-vivo, EF24 inhibited tumor growth in a dose-dependent manner. Moreover, no pathological changes of heart, lung, spleen, kidney and liver of mice were observed. Collectively, EF24 induced ROS accumulation, in turn activates cell apoptosis, and then exerts its cytotoxicity on NSCLC cells.

Conclusions

The results showed that EF24 exerted cytotoxicity against NSCLC via ROS accumulation. Thus, EF24 might serve as a potential anti-cancer agent for the treatment of NSCLC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02240-z.

Antidepressants and Antipsychotic Agents as Repurposable Oncological Drug Candidates

Drug repurposing, also known as drug repositioning/reprofiling, is a relatively new strategy for the identification of alternative uses of well-known therapeutics that are outside the scope of their original medical indications. Such an approach might entail a number of advantages compared to standard de novo drug development, including less time needed to introduce the drug to the market, and lower costs. The group of compounds that could be considered as promising candidates for repurposing in oncology include the central nervous system drugs, especially selected antidepressant and antipsychotic agents. In this article, we provide an overview of some antidepressants (citalopram, fluoxetine, paroxetine, sertraline) and antipsychotics (chlorpromazine, pimozide, thioridazine, trifluoperazine) that have the potential to be repurposed as novel chemotherapeutics in cancer treatment, as they have been found to exhibit preventive and/or therapeutic action in cancer patients. Nevertheless, although drug repurposing seems to be an attractive strategy to search for oncological drugs, we would like to clearly indicate that it should not replace the search for new lead structures, but only complement de novo drug development.

Thioridazine requires calcium influx to induce MLL-AF6-rearranged AML cell death

In pediatric acute myeloid leukemia (AML), intensive chemotherapy and allogeneic hematopoietic stem cell transplantation are the cornerstones of treatment in high-risk cases, with severe late effects and a still high risk of disease recurrence as the main drawbacks. The identification of targeted, more effective, safer drugs is thus desirable. We performed a high-throughput drug-screening assay of 1280 compounds and identified thioridazine (TDZ), a drug that was highly selective for the t(6;11)(q27;q23) MLL-AF6 (6;11)AML rearrangement, which mediates a dramatically poor (below 20%) survival rate. TDZ induced cell death and irreversible progress toward the loss of leukemia cell clonogenic capacity in vitro. Thus, we explored its mechanism of action and found a profound cytoskeletal remodeling of blast cells that led to Ca2+ influx, triggering apoptosis through mitochondrial depolarization, confirming that this latter phenomenon occurs selectively in t(6;11)AML, for which AF6 does not work as a cytoskeletal regulator, because it is sequestered into the nucleus by the fusion gene. We confirmed TDZ-mediated t(6;11)AML toxicity in vivo and enhanced the drug's safety by developing novel TDZ analogues that exerted the same effect on leukemia reduction, but with lowered neuroleptic effects in vivo. Overall, these results refine the MLL-AF6 AML leukemogenic mechanism and suggest that the benefits of targeting it be corroborated in further clinical trials.

Revisiting Platinum-Based Anticancer Drugs to Overcome Gliomas

Although there are many patients with brain tumors worldwide, there are numerous difficulties in overcoming brain tumors. Among brain tumors, glioblastoma, with a 5-year survival rate of 5.1%, is the most malignant. In addition to surgical operations, chemotherapy and radiotherapy are generally performed, but the patients have very limited options. Temozolomide is the most commonly prescribed drug for patients with glioblastoma. However, it is difficult to completely remove the tumor with this drug alone. Therefore, it is necessary to discuss the potential of anticancer drugs, other than temozolomide, against glioblastomas. Since the discovery of cisplatin, platinum-based drugs have become one of the leading chemotherapeutic drugs. Although many studies have reported the efficacy of platinum-based anticancer drugs against various carcinomas, studies on their effectiveness against brain tumors are insufficient. In this review, we elucidated the anticancer effects and advantages of platinum-based drugs used in brain tumors. In addition, the cases and limitations of the clinical application of platinum-based drugs are summarized. As a solution to overcome these obstacles, we emphasized the potential of a novel approach to increase the effectiveness of platinum-based drugs.

Targeting Cancer Stem Cells with Differentiation Agents as an Alternative to Genotoxic Chemotherapy for the Treatment of Malignant Testicular Germ Cell Tumors

Testicular germ cell tumors (TGCTs) are exceptionally sensitive to genotoxic chemotherapy, resulting in a high cure rate for the young men presenting with these malignancies. However, this treatment is associated with significant toxicity, and a subset of malignant TGCTs demonstrate chemoresistance. Mixed nonseminomas often contain pluripotent embryonal carcinoma (EC) cells, the cancer stem cells (CSCs) of these tumors. We hypothesized that differentiation therapy, a treatment strategy which aims to induce differentiation of tumor-propagating CSCs to slow tumor growth, could effectively treat mixed nonseminomas without significant toxicity. The FDA-approved antipsychotic thioridazine and the agricultural antibiotic salinomycin are two drugs previously found to selectively target CSCs, and here we report that these agents differentiate EC cells in vitro and greatly reduce their tumorigenic potential in vivo. Using a novel transformed induced pluripotent stem cell allograft model and a human xenograft model, we show that thioridazine extends the survival of tumor-bearing mice and can reduce the number of pluripotent EC cells within tumors. These results suggest that thioridazine could be repurposed as an alternative TGCT treatment that avoids the toxicity of conventional chemotherapeutics.

SHP2 Nuclear/Cytoplasmic Trafficking in Granulosa Cells Is Essential for Oocyte Meiotic Resumption and Maturation

Src-homology-2-containing phosphotyrosine phosphatase (SHP2), a classic cytoplasmic protein and a major regulator of receptor tyrosine kinases and G protein-coupled receptors, plays a significant role in preimplantation embryo development. In this study, we deciphered the role of SHP2 in the somatic compartment of oocytes during meiotic maturation. SHP2 showed nuclear/cytoplasmic localization in bovine cumulus and human granulosa (COV434) cells. Follicle-stimulating hormone (FSH) treatment significantly enhanced cytoplasmic SHP2 localization, in contrast to the E₂ treatment, which augmented nuclear localization. Enhanced cytoplasmic SHP2 was found to negatively regulate the expression of the ERα-transcribed NPPC and NPR2 mRNAs, which are vital for oocyte meiotic arrest. The co-immunoprecipitation results revealed the presence of the SHP2/ERα complex in the germinal vesicle-stage cumulus-oocyte complexes, and this complex significantly decreased with the progression of meiotic maturation. The complex formation between ERα and SHP2 was also confirmed by using a series of computational modeling methods. To verify the correlation between SHP2 and NPPC/NPR2, SHP2 was knocked down via RNA interference, and NPPC and NPR2 mRNAs were analyzed in the control, E₂, and FSH-stimulated COV434 cells. Furthermore, phenyl hydrazonopyrazolone sulfonate 1, a site-directed inhibitor of active SHP2, showed no significant effect on the ERα-transcribed NPPC and NPR2 mRNAs. Taken together, these findings support a novel nuclear/cytoplasmic role of SHP2 in oocyte meiotic resumption and maturation.

Pharmacological targeting of c-FLIPL and Bcl-2 family members promotes apoptosis in CD95L-resistant cells

The development of efficient combinatorial treatments is one of the key tasks in modern anti-cancer therapies. An apoptotic signal can either be induced by activation of death receptors (DR) (extrinsic pathway) or via the mitochondria (intrinsic pathway). Cancer cells are characterized by deregulation of both pathways. Procaspase-8 activation in extrinsic apoptosis is controlled by c-FLIP proteins. We have recently reported the small molecules FLIPinB/FLIPinBγ targeting c-FLIP_L in the caspase-8/c-FLIP_L heterodimer. These small molecules enhanced caspase-8 activity in the death-inducing signaling complex (DISC), CD95L/TRAIL-induced caspase-3/7 activation and subsequent apoptosis. In this study to increase the pro-apoptotic effects of FLIPinB/FLIPinBγ and enhance its therapeutic potential we investigated costimulatory effects of FLIPinB/FLIPinBγ in combination with the pharmacological inhibitors of the anti-apoptotic Bcl-2 family members such as ABT-263 and S63845. The combination of these inhibitors together with FLIPinB/FLIPinBγ increased CD95L-induced cell viability loss, caspase activation and apoptosis. Taken together, our study suggests new approaches for the development of combinatorial anti-cancer therapies specifically targeting both intrinsic and extrinsic apoptosis pathways.

ROS-Mediated Therapeutic Strategy in Chemo-/Radiotherapy of Head and Neck Cancer

Head and neck cancer is a highly genetic and metabolic heterogeneous collection of malignancies of the lip, oral cavity, salivary glands, pharynx, esophagus, paranasal sinuses, and larynx with five-year survival rates ranging from 12% to 93%. Patients with head and neck cancer typically present with advanced stage III, IVa, or IVb disease and are treated with comprehensive modality including chemotherapy, radiotherapy, and surgery. Despite advancements in treatment modality and technique, noisome recurrence, invasiveness, and resistance as well as posttreatment complications severely influence survival rate and quality of life. Thus, new therapeutic strategies are urgently needed that offer enhanced efficacy with less toxicity. ROS in cancer cells plays a vital role in regulating cell death, DNA repair, stemness maintenance, metabolic reprogramming, and tumor microenvironment, all of which have been implicated in resistance to chemo-/radiotherapy of head and neck cancer. Adjusting ROS generation and elimination to reverse the resistance of cancer cells without impairing normal cells show great hope in improving the therapeutic efficacy of chemo-/radiotherapy of head and neck cancer. In the current review, we discuss the pivotal and targetable redox-regulating system including superoxide dismutases (SODs), tripeptide glutathione (GSH), thioredoxin (Trxs), peroxiredoxins (PRXs), nuclear factor erythroid 2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2/keap1), and mitochondria electron transporter chain (ETC) complexes and their roles in regulating ROS levels and their clinical significance implicated in chemo-/radiotherapy of head and neck cancer. We also summarize several old drugs (referred to as the non-anti-cancer drugs used in other diseases for a long time) and small molecular compounds as well as natural herbs which effectively modulate cellular ROS of head and neck cancer to synergize the efficacy of conventional chemo-/radiotherapy. Emerging interdisciplinary techniques including photodynamic, nanoparticle system, and Bio-Electro-Magnetic-Energy-Regulation (BEMER) therapy are promising measures to broaden the potency of ROS modulation for the benefit of chemo-/radiotherapy in head and neck cancer.

Targeting Cellular Metabolism Modulates Head and Neck Oncogenesis

Considering the great energy and biomass demand for cell survival, cancer cells exhibit unique metabolic signatures compared to normal cells. Head and neck squamous cell carcinoma (HNSCC) is one of the most prevalent neoplasms worldwide. Recent findings have shown that environmental challenges, as well as intrinsic metabolic manipulations, could modulate HNSCC experimentally and serve as clinic prognostic indicators, suggesting that a better understanding of dynamic metabolic changes during HNSCC development could be of great benefit for developing adjuvant anti-cancer schemes other than conventional therapies. However, the following questions are still poorly understood: (i) how does metabolic reprogramming occur during HNSCC development? (ii) how does the tumorous milieu contribute to HNSCC tumourigenesis? and (iii) at the molecular level, how do various metabolic cues interact with each other to control the oncogenicity and therapeutic sensitivity of HNSCC? In this review article, the regulatory roles of different metabolic pathways in HNSCC and its microenvironment in controlling the malignancy are therefore discussed in the hope of providing a systemic overview regarding what we knew and how cancer metabolism could be translated for the development of anti-cancer therapeutic reagents.

Clinical update on head and neck cancer: molecular biology and ongoing challenges

Head and neck squamous cell carcinomas (HNSCCs) are an aggressive, genetically complex and difficult to treat group of cancers. In lieu of truly effective targeted therapies, surgery and radiotherapy represent the primary treatment options for most patients. But these treatments are associated with significant morbidity and a reduction in quality of life. Resistance to both radiotherapy and the only available targeted therapy, and subsequent relapse are common. Research has therefore focussed on identifying biomarkers to stratify patients into clinically meaningful groups and to develop more effective targeted therapies. However, as we are now discovering, the poor response to therapy and aggressive nature of HNSCCs is not only affected by the complex alterations in intracellular signalling pathways but is also heavily influenced by the behaviour of the extracellular microenvironment. The HNSCC tumour landscape is an environment permissive of these tumours' aggressive nature, fostered by the actions of the immune system, the response to tumour hypoxia and the influence of the microbiome. Solving these challenges now rests on expanding our knowledge of these areas, in parallel with a greater understanding of the molecular biology of HNSCC subtypes. This update aims to build on our earlier 2014 review by bringing up to date our understanding of the molecular biology of HNSCCs and provide insights into areas of ongoing research and perspectives for the future.

AXL knockdown gene signature reveals a drug repurposing opportunity for a class of antipsychotics to reduce growth and metastasis of triple-negative breast cancer

Triple-Negative Breast Cancer (TNBC) is an aggressive cancer subtype that is associated with a poor prognosis due to its propensity to form metastases. The receptor tyrosine kinase AXL plays a role in tumor cell dissemination and its expression in breast cancers correlates with poor patient survival. Here, we explored whether already used drugs might elicit a gene signature similar to that seen with AXL knockdown in TNBC cells and which could, therefore, offer an opportunity for drug repurposing. To this end, we queried the Connectivity Map with an AXL gene signature which revealed a class of dopamine receptors antagonists named phenothiazines (Thioridazine, Fluphenazine and Trifluoperazine) typically used as anti-psychotics. We next tested if these drugs, similarly to AXL depletion, were able to limit growth and metastatic progression of TNBC cells and found that phenothiazines are able to reduce cell invasion, proliferation, viability and increase apoptosis of TNBC cells in vitro. Mechanistically, these drugs did not affect AXL activity but instead reduced PI3K/AKT/mTOR and ERK signaling. When administered to mice bearing TNBC xenografts, phenothiazines were able to reduce tumor growth and metastatic burden. Collectively, these results suggest that these antipsychotics display anti-tumor and anti-metastatic activity and that they could potentially be repurposed, in combination with standard chemotherapy, for the treatment of TNBC.

Targeting the TLK1/NEK1 DDR axis with Thioridazine suppresses outgrowth of androgen independent prostate tumors

Standard therapy for advanced Prostate Cancer (PCa) consists of antiandrogens, which provide respite from disease progression, but ultimately fail resulting in the incurable phase of the disease: mCRPC. Targeting PCa cells before their progression to mCRPC would greatly improve the outcome. Combination therapy targeting the DNA Damage Response (DDR) has been limited by general toxicity, and a goal of clinical trials is how to target the DDR more specifically. We now show that androgen deprivation therapy (ADT) of LNCaP cells results in increased expression of TLK1B, a key kinase upstream of NEK1 and ATR and mediating the DDR that typically results in a temporary cell cycle arrest of androgen responsive PCa cells. Following DNA damage, addition of the TLK specific inhibitor, thioridazine (THD), impairs ATR and Chk1 activation, establishing the existence of a ADT > TLK1 > NEK1 > ATR > Chk1, DDR pathway, while its abrogation leads to apoptosis. Treatment with THD suppressed the outgrowth of androgen‐independent (AI) colonies of LNCaP and TRAMP‐C2 cells cultured with bicalutamide. Moreover, THD significantly inhibited the growth of several PCa cells in vitro (including AI lines). Administration of THD or bicalutamide was not effective at inhibiting long‐term tumor growth of LNCaP xenografts. In contrast, combination therapy remarkably inhibited tumor growth via bypass of the DDR. Moreover, xenografts of LNCaP cells overexpressing a NEK1‐T141A mutant were durably suppressed with bicalutamide. Collectively, these results suggest that targeting the TLK1/NEK1 axis might be a novel therapy for PCa in combination with standard of care (ADT).

What's new?

Standard therapy for advanced Prostate Cancer (PCa) consists of anti‐androgens, which only provide temporary respite from disease progression to metastatic castrate‐resistant prostate cancer (mCRPC). Here, the authors show in the LNCaP cell model that the increased expression with ADT of TLK1B, a prosurvival checkpoint pathway that is enacted before conversion to androgen‐independent growth, offers a unique target for attacking more specifically PCa cells before their conversion to CRPC. Moreover, they suggest to re‐purpose thioridazine or other phenothiazine antipsychotic drugs as inhibitors of the TLK1 > Nek1 > ATR > Chk1 DNA Damage Response (DDR) axis for the early treatment of advanced PCa still responsive to ADT.

The distribution of novel biomarkers in carcinoma-in-situ, microinvasive, and squamous cell carcinoma of the uterine cervix

Importin-β, exportin-5, p16, Ki-67, Mcl1, PDL1, and cFLIP are each over-expressed in the majority of CIN 1 lesions. These biomarkers, plus HPV E6/E7 RNA, were analyzed in carcinoma-in-situ (CIS), microinvasive, and squamous cell carcinoma (SCC) of the uterine cervix and cervical carcinoma cell lines. Only p16 and Ki-67 continued to be over-expressed in CIS, with a concomitant marked increase in E6/E7 RNA. There was a highly significant increase in PDL1 expression and decrease in Ki-67 (each p < 0.001) in microinvasive cancer compared to CIS whereas p16 and E6/E7 remained stable. As the lesion progressed to SCC, p16 and E6/E7 RNA remained strongly overexpressed with a concomitant over expression of importin-β and Ki67. HPV positive Caski cells showed significant elevations of p16, importin-β, exportin-5 and PDL1 compared to the HPV negative cervical cancer cell line C33A, consistent with viral induction of these biomarkers. The data suggest that PDL1 may be a useful biomarker to differentiate CIS from microinvasive cancer and, thus, anti-PDL1 therapy may inhibit the progression of CIS to the invasive stage.

Induction of immunosuppressive functions and NF-κB by FLIP in monocytes

Immunosuppression is a hallmark of tumor progression, and treatments that inhibit or deplete monocytic myeloid-derived suppressive cells could promote anti-tumor immunity. c-FLIP is a central regulator of caspase-8-mediated apoptosis and necroptosis. Here we show that low-dose cytotoxic chemotherapy agents cause apoptosis linked to c-FLIP down-regulation selectively in monocytes. Enforced expression of c-FLIP or viral FLIP rescues monocytes from cytotoxicity and concurrently induces potent immunosuppressive activity, in T cell cultures and in vivo models of tumor progression and immunotherapy. FLIP-transduced human blood monocytes can suppress graft versus host disease. Neither expression of FLIP in granulocytes nor expression of other anti-apoptotic genes in monocytes conferred immunosuppression, suggesting that FLIP effects on immunosuppression are specific to monocytic lineage and distinct from death inhibition. Mechanistically, FLIP controls a broad transcriptional program, partially by NF-κB activation. Therefore, modulation of FLIP in monocytes offers a means to elicit or block immunosuppressive myeloid cells.

Signaling and transcriptional regulation of MDSC activity remains largely undefined. Here the authors show that monocytic MDSC immunosuppression is triggered by c-FLIP and requires NFκB, implicate this axis in cancer prognosis and response to therapy, and employ ectopic FLIP to treat immunopathology.

Association between Thioridazine Use and Cancer Risk in Adult Patients with Schizophrenia-A Population-Based Study

OBJECTIVE

Several cell line studies have demonstrated thioridazine's anticancer, multidrug resistance-reversing and apoptosis-inducing properties in various tumors. We conducted this nationwide population-based study to investigate the association between thioridazine use and cancer risk among adult patients with schizophrenia.

METHODS

Based on the Psychiatric Inpatient Medical Claim of the National Health Insurance Research Database of Taiwan, a total of 185,689 insured psychiatric patients during 2000 to 2005 were identified. After excluding patients with prior history of schizophrenia, only 42,273 newly diagnosed patients were included. Among them, 1,631 patients ever receiving thioridazine for more than 30 days within 6 months were selected and paired with 6,256 randomly selected non-thioridazine controls. These patients were traced till 2012/12/31 to see if they have any malignancy.

RESULTS

The incidence rates of hypertension and cerebrovascular disease were higher among cases than among matched controls. The incidence of hyperlipidemia, coronary artery disease and chronic pulmonary disease did not differ between the two groups. By using Cox proportional hazard model for cancer incidence, the crude hazard ratio was significantly higher in age, hypertension, hyperlipidemia, cerebrovascular disease, coronary artery disease and chronic pulmornary disease. However, after adjusting for other covariates, only age and hypertension remained significant. Thioridazine use in adult patients with schizophrenia had no significant association with cancer.

CONCLUSION

Despite our finding that thioridazine use had no prevention in cancer in adult patients with schizophrenia. Based on the biological activity, thioridazine is a potential anticancer drug and further investigation in human with cancer is warranted.

Identification of key candidate genes and small molecule drugs in cervical cancer by bioinformatics strategy

Purpose

Cervical cancer (CC) is one of the most common malignant tumors among women. The present study aimed at integrating two expression profile datasets to identify critical genes and potential drugs in CC.

Materials and methods

Expression profiles, GSE7803 and GSE9750, were integrated using bioinformatics methods, including differentially expressed genes analysis, Kyoto Encyclopedia of Genes and Genomes pathway analysis, and protein–protein interaction (PPI) network construction. Subsequently, survival analysis was performed among the key genes using Gene Expression Profiling Interactive Analysis websites. Connectivity Map (CMap) was used to query potential drugs for CC.

Results

A total of 145 upregulated genes and 135 downregulated genes in CC were identified. The functional changes of these differentially expressed genes related to CC were mainly associated with cell cycle, DNA replication, p53 signaling pathway, and oocyte meiosis. A PPI network was identified by STRING with 220 nodes and 2,111 edges. Thirteen key genes were identified as the intersecting genes of the enrichment pathways and the top 20 nodes in PPI network. Survival analysis revealed that high mRNA expression of MCM2, PCNA, and RFC4 was significantly associated with longer overall survival, and the survival was significantly better in the low-expression RRM2 group. Moreover, CMap predicted nine small molecules as possible adjuvant drugs to treat CC.

Conclusion

Our study found key dysregulated genes involved in CC and potential drugs to combat it, which might provide insights into CC pathogenesis and might shed light on potential CC treatments.

Pharmacological Targeting of Cell Cycle, Apoptotic and Cell Adhesion Signaling Pathways Implicated in Chemoresistance of Cancer Cells

Chemotherapeutic drugs target a physiological differentiating feature of cancer cells as they tend to actively proliferate more than normal cells. They have well-known side-effects resulting from the death of highly proliferative normal cells in the gut and immune system. Cancer treatment has changed dramatically over the years owing to rapid advances in oncology research. Developments in cancer therapies, namely surgery, radiotherapy, cytotoxic chemotherapy and selective treatment methods due to better understanding of tumor characteristics, have significantly increased cancer survival. However, many chemotherapeutic regimes still fail, with 90% of the drug failures in metastatic cancer treatment due to chemoresistance, as cancer cells eventually develop resistance to chemotherapeutic drugs. Chemoresistance is caused through genetic mutations in various proteins involved in cellular mechanisms such as cell cycle, apoptosis and cell adhesion, and targeting those mechanisms could improve outcomes of cancer therapy. Recent developments in cancer treatment are focused on combination therapy, whereby cells are sensitized to chemotherapeutic agents using inhibitors of target pathways inducing chemoresistance thus, hopefully, overcoming the problems of drug resistance. In this review, we discuss the role of cell cycle, apoptosis and cell adhesion in cancer chemoresistance mechanisms, possible drugs to target these pathways and, thus, novel therapeutic approaches for cancer treatment.

Regulation of the antiapoptotic protein cFLIP by the glucocorticoid Dexamethasone in ALL cells

We recently reported that the Smac mimetic BV6 and glucocorticoids, e.g. Dexamethasone (Dexa), synergize to induce cell death in acute lymphoblastic leukemia (ALL) in vitro and in vivo. Here, we discover that this synergism involves Dexa-stimulated downregulation of cellular FLICE-like inhibitory protein (cFLIP) in ALL cells. Dexa rapidly decreases cFLIP_L protein levels, which is further enhanced by addition of BV6. While attenuating the activation of non-canonical nuclear factor-kappaB (NF-κB) signaling by BV6, Dexa suppresses cFLIP_L protein but not mRNA levels pointing to a transcription-independent downregulation of cFLIP_L by Dexa. Analysis of protein degradation pathways indicates that Dexa causes cFLIP_L depletion independently of proteasomal, lysosomal or caspase pathways, as inhibitors of the proteasome, lysosomal enzymes or caspases all failed to protect from Dexa-mediated loss of cFLIP_L protein. Also, Dexa alone or in combination with BV6 does not affect overall activity of the proteasome. Importantly, overexpression of cFLIP_L to an extent that is no longer subject to Dexa-imposed downregulation rescues Dexa/BV6-mediated cell death. Vice versa, knockdown of cFLIP increases BV6-mediated cell death, thus mimicking the effect of Dexa. Altogether, these data demonstrate that Dexa-mediated downregulation of cFLIP_L protein promotes Dexa/BV6-mediated cell death, thereby providing novel insights into the synergistic antitumor activity of this combination treatment.

Antipsychotic dopamine receptor antagonists, cancer, and cancer stem cells

Cancer is one of the deadliest diseases in the world. Despite extensive studies, treating metastatic cancers remains challenging. Years of research have linked a rare set of cells known as cancer stem cells (CSCs) to drug resistance, leading to the suggestion that eradication of CSCs might be an effective therapeutic strategy. However, few drug candidates are active against CSCs. New drug discovery is often a lengthy process. Drug screening has been advantageous in identifying drug candidates. Current understanding of cancer biology has revealed various clues to target cancer from different points of view. Many studies have found dopamine receptors (DRs) in various cancers. Therefore, DR antagonists have attracted a lot of attention in cancer research. Recently, a group of antipsychotic DR antagonists has been demonstrated to possess remarkable abilities to restrain and sensitize CSCs to existing chemotherapeutics by a process called differentiation approach. In this review, we will describe current aspects of CSC-targeting therapeutics, antipsychotic DR antagonists, and their extraordinary abilities to fight cancer.

Activation of Fas/FasL pathway and the role of c-FLIP in primary culture of human cholangiocarcinoma cells

Intrahepatic cholangiocarcinoma (iCCA) represents a heterogeneous group of malignancies emerging from the biliary tree, often in the context of chronic bile ducts inflammation. The immunological features of iCCA cells and their capability to control the lymphocytes response have not yet been investigated. The aims of the present study were to evaluate the interaction between iCCA cells and human peripheral blood mononuclear cells (PBMCs) and the role of Fas/FasL in modulating T-cells and NK-cells response after direct co-culture. iCCA cells express high levels of Fas and FasL that increase after co-culture with PBMCs inducing apoptosis in CD4⁺, CD8⁺ T-cells and in CD56⁺ NK-cells. In vitro, c-FLIP is expressed in iCCA cells and the co-culture with PBMCs induces an increase of c-FLIP in both iCCA cells and biliary tree stem cells. This c-FLIP increase does not trigger the caspase cascade, thus hindering apoptotis of iCCA cells which, instead, underwent proliferation. The increased expression of Fas, FasL and c-FLIP is confirmed in situ, in human CCA and in primary sclerosing cholangitis. In conclusion our data indicated that iCCA cells have immune-modulatory properties by which they induce apoptosis of T and NK cells, via Fas/FasL pathway, and escape inflammatory response by up-regulating c-FLIP system.