Phenothiazine Inhibitors of TLKs Affect Double-Strand Break Repair and DNA Damage Response Recovery and Potentiate Tumor Killing with Radiomimetic Therapy

Ronald, Sharon; Awate, Sanket; Rath, Abhijit; Carroll, Jennifer L.; Galiano, Floyd; Dwyer, Donard S.; Kleiner-Hancock, Heather E; Mathis, J. Michael; Vigod, Simone N.; Benedetti, Arrigo De

doi:10.1177/1947601913479020

Cited by 47 publications

(66 citation statements)

References 59 publications

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“…This suggests that THD may indeed be a more targeted anticancer agent, or it is possible that the TLK1/Nek1 axis remains critical even for CRPC cells. However, we previously reported that THD delays, but does not eventually prevent, the growth of PC3 subcutaneous tumors . Note also that LNCaP cells grown in FCS‐medium were not much affected by THD, again suggesting that a large part of inhibition of the AI growth of these cells in CSS could be mediated via the TLK1/Nek1 DDR axis.…”

Section: Resultssupporting

confidence: 72%

“…Inhibition of the TLK1/NEK1 axis with thioridazine (THD), a rather specific inhibitor of TLKs, suppresses the DDR. THD was previously shown to improve therapeutic response in combination with DNA damaging agents . Furthermore, THD was shown to cause growth inhibition of ovarian cancer cells via suppression of AKT activity by an unidentified mechanism downstream of PI3K and mTOR, but which we now propose could be the result of inhibition of TLK1 and another of its targets, AKTIP, which is a direct activator of AKT.…”

Section: Introductionmentioning

confidence: 78%

“…We recently uncovered the proteome target of TLK1 and identified the NIMA‐related kinase, NEK1, as a major substrate, a key kinase which in turn activates ATR and the DDR . Inhibition of the TLK1/NEK1 axis with thioridazine (THD), a rather specific inhibitor of TLKs, suppresses the DDR. THD was previously shown to improve therapeutic response in combination with DNA damaging agents .…”

Section: Introductionmentioning

confidence: 99%

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

Singh

Jaiswal

Ghosh

et al. 2019

Intl Journal of Cancer

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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).

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Section: Resultssupporting

confidence: 72%

Section: Introductionmentioning

confidence: 78%

Section: Introductionmentioning

confidence: 99%

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

Singh

Jaiswal

Ghosh

et al. 2019

Intl Journal of Cancer

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“…To determine if kinase-repressed cells would be susceptible to ionizing radiation induced-cell killing, a known TLK1 inhibitor, thioridazine (THD) was used 18 . NS-SV-AC cells were extremely sensitive to the drug, and drug incubation was limited to an hour before radiation (Figure S1A, Supplementary Material).…”

Section: Resultsmentioning

confidence: 99%

Tousled kinase activator, gallic acid, promotes homologous recombinational repair and suppresses radiation cytotoxicity in salivary gland cells

Shanmugam

Nair

Benedetti

et al. 2016

Free Radical Biology and Medicine

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Accidental or medical radiation exposure of the salivary glands can gravely impact oral health. Previous studies have shown the importance of Tousled-like kinase 1 (TLK1) and its alternate start variant TLK1B in cell survival against genotoxic stresses. Through a high-throughput library screening of natural compounds, the phenolic phytochemical, gallic acid (GA), was identified as a modulator of TLK1/1B. This small molecule possesses anti-oxidant and free radical scavenging properties, but in this study, we report that in vitro it promotes survival of human salivary acinar cells, NS-SV-AC, through repair of ionizing radiation damage. Irradiated cells treated with GA show improved clonogenic survival compared to untreated controls. And, analyses of DNA repair kinetics by alkaline single-cell gel electrophoresis and γ-H2AX foci immunofluorescence indicate rapid resolution of DNA breaks in drug-treated cells. Study of DR-GFP transgene repair indicates GA facilitates homologous recombinational repair to establish a functional GFP gene. In contrast, inactivation of TLK1 or its shRNA knockdown suppressed resolution of radiation-induced DNA tails in NS-SV-AC, and homology directed repair in DRGFP cells. Consistent with our results in culture, animals treated with GA after exposure to fractionated radiation showed better preservation of salivary function compared to saline-treated animals. Our results suggest that GA-mediated transient modulation of TLK1 activity promotes DNA repair and suppresses radiation cytoxicity in salivary gland cells.

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“…It may have practical importance, for example, in case of tumors with high TCTP expression (56). Furthermore, thioridazine is able to block the socalled Tousled-like kinases, which are responsible for the chromatin rearrangement in the S-phase of the cell cycle, and the inhibition of which consequently leads to genomic instability and apoptosis (57). Similar processes may exist in the background of the observations that thioridazine reduces the expression of cyclin D1 and cyclin-dependent kinase 4 (CDK4), and increases the expression of CDK inhibitor proteins, such as p16 and p27.…”

Section: Antitumor Effectmentioning

confidence: 99%

Possible Biological and Clinical Applications of Phenothiazines

Varga

Csonka

et al. 2017

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Abstract. Phenothiazines have been used in many areasPhenothiazines are unanimously one of the most versatile compounds from the view of biological activity. Since their discovery, new exploitable pharmacological properties have emerged from time to time; thus, they have an important role in many areas of medicine and beyond. This is why phenothiazines are basic compounds in pharmacology. The history of these compounds goes back to the second half of the 19th century, when a German chemist, Heinrich August Bernthsen began to study the structure of methylene blue, which was first synthesized in 1876 by Heinrich Caro. In 1885, two years after Bernthsen first managed to produce phenothiazine, he also succeeded in describing the structure of methylene blue (1). At the same time, Paul Ehrlich began to investigate the possible therapeutic use of methylene blue in malaria infections, which he first published in 1891 (2). Due to this, methylene blue was often prescribed for patients with malaria in the subsequent period (3).Research conducted in the 1930s and '40s proved the potential wide use of phenothiazines. The insecticidal (4), antihelmintic (5, 6), and antibacterial (7) effects of the compound were detected; however, it was not widely used for these purposes. In the 1940s, another novel phenothiazine derivative, namely promethazine was brought to the forefront of attention; it was investigated by Paul Charpentier at the Rhone-Poulenc laboratory in Paris (8). It was shown that promethazine had an antihistamine effect (9), which was later used in the therapy of allergic diseases and in anesthesia (10,11). A few years later in the same laboratory, chlorpromazine was discovered, which has strong anxiolytic and antipsychotic effect along with its antihistaminic effect (12). Psychiatry fully exploited this feature in psychotic patients (13), which resulted in the almost complete emptying of psychiatric hospitals in the 1950s. As a result, the discovery of chlorpromazine and the beginning of its use as an antipsychotic are considered the beginning of modern psychiatry and psychopharmacology.Since then, several antipsychotic phenothiazine compounds have been used in clinical practice, although research conducted in the last couple of decades indicated that phenothiazine compounds could have an important role in other fields of medicine as well, such as in the treatment of tumorous, infectious, or neurodegenerative diseases (3). 5983

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Phenothiazine Inhibitors of TLKs Affect Double-Strand Break Repair and DNA Damage Response Recovery and Potentiate Tumor Killing with Radiomimetic Therapy

Cited by 47 publications

References 59 publications

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

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

Tousled kinase activator, gallic acid, promotes homologous recombinational repair and suppresses radiation cytotoxicity in salivary gland cells

Possible Biological and Clinical Applications of Phenothiazines

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