Fundamental & Clinical Pharmacology最新文献

Background: DNA repair plays a major role in maintaining genomic stability, thus limiting the transformation of normal cells into cancer cells. However, in cancer patients treated with DNA-targeting drugs, DNA repair can decrease efficacy by removing the damage generated by such molecules that is needed to induce pharmacological activity. Inhibiting DNA repair thus represents an interesting approach to potentiating the activity of chemotherapy in this setting.

Objectives: Here, we continue the characterization of an inhibitor of the interaction between Excision Repair Cross-Complementing Rrodent repair deficiency complementation group 1 (ERCC1) and Xeroderma Pigmentousum group F (XPF) (B9), two key proteins of nucleotide excision repair.

Methods: We used various cell lines and co-incubation studies for the determination of cell survival and DNA repair capacities.

Results: We show that it is synergistic with other platinum derivatives than previously described, and that synergy is lacking in cells not expressing ERCC1 or XPF. Finally, a series of experiments show that potentiation is observed only in cells expressing wild-type p53.

Conclusion: Our results confirm the mechanism of action of our ERCC1-XPF inhibitor and give important additional data on this approach to enhance the activity of already existing cancer drugs.

Background: Small cell lung cancer (SCLC) is a highly aggressive type of lung cancer for which platinum-based chemotherapy is the standard of care. Despite an initial response to this therapy, patients eventually develop resistance to the chemotherapy.

Objectives: To investigate the potential of capivasertib, an approved drug for advanced breast cancer, to enhance the efficacy of cisplatin in preclinical SCLC models and explore the underlying mechanisms.

Methods: SCLC cell lines were treated with capivasertib and cisplatin, alone or in combination, to assess cell viability, proliferation, colony formation, and apoptosis. Next, capivasertib's effects, alone and combined with cisplatin, were evaluated in an SCLC mouse model. Mechanistic studies focused on Akt and MYC signaling, with constitutively active Akt overexpression used to assess its role.

Results: Capivasertib is active against a panel of SCLC cell lines regardless of cellular origin and genetic profiling with IC50 at a clinically achievable range. Particularly, capivasertib inhibits proliferation and anchorage-independent colony formation and induces apoptosis in SCLC cells. It significantly augments cisplatin's inhibitory effects in all tested cell lines. Importantly, capivasertib at a non-toxic dose is effective in delaying SCLC growth in mice and its combination with cisplatin achieves nearly complete tumor growth inhibition. Mechanistic studies confirm that capivasertib inhibits Akt and MYC signaling, and furthermore, that overexpression of constitutively active Akt reversed anti-SCLC activity of capivasertib.

Conclusion: Our work is the first to reveal that Akt inhibition can augment chemotherapy in SCLC, and capivasertib is a useful addition to the treatment armamentarium for SCLC.

Background: Fibromyalgia (FM) is a syndrome of pervasive chronic pain accompanied by low mood, sleep disorders, and cognitive decline. The dysfunction of central pain processing systems along with neurotransmitter disturbances are possible contributing mechanisms. Genetic polymorphism of the 𝛽2 adrenergic receptors is reported in FM patients. It is reported that chronic β2 agonists administration is effective for neuropathic pain alleviation. No current information, however, exists on their potential to alleviate nociplastic pain, such as FM. Therefore, the purpose of the current study is to examine salmeterol's potential antiallodynic effects in experimentally produced FM and explore some of the possible contributing mechanisms.

Methods: Thirty rats are allocated into three groups (n = 10): a normal group, a reserpine group that received reserpine (1 mg/kg; s.c.) for 3 days, and a reserpine + salmeterol group that received salmeterol (1 mg/kg; i.p.) for 21 consecutive days following last reserpine injection.

Results: Reserpine administration resulted in behavioral and biochemical changes consistent with FM, including thermal and mechanical hyperalgesia, depressive behavior, and motor incoordination. This is coupled with disturbed spinal monoamine levels, depressed cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling, disturbed mitochondrial function/dynamics, and compromised blood-nerve barrier integrity. Treatment with salmeterol conceivably reversed these effects.

Conclusion: β2 receptor agonists such as salmeterol could be regarded as a promising strategy for the management of FM.

Background: Oxatomide, an antihistamine drug of the diphenylmethylpiperazine family, has anti-inflammatory effects in airway disease. Because oxatomide was shown to cause diverse physiological responses in several cell models, the impact of oxatomide on Ca²⁺ signaling and its related physiological effects has not been explored in IMR-90 human fetal lung fibroblasts.

Objectives: This study assessed the effect of oxatomide on cell viability and intracellular free Ca²⁺ concentrations ([Ca²⁺]_i) and examined whether oxatomide-induced cytotoxicity through Ca²⁺ signaling in IMR-90 cells.

Methods: Cell viability was measured by the cell proliferation reagent (WST-1). [Ca²⁺]_i was measured by the Ca²⁺-sensitive fluorescent dye fura-2.

Results: Oxatomide (10-40 μM) concentration dependently reduced cell viability and induced [Ca²⁺]_i rises in IMR-90 cells. This cytotoxic effect was reversed by chelation of cytosolic Ca²⁺ with BAPTA-AM. In terms of Ca²⁺ signaling, oxatomide-caused Ca²⁺ entry was inhibited by modulators of store-operated Ca²⁺ channels (2-APB and SKF96365) and protein kinase C (PKC) inhibitor (GF109203X). Furthermore, oxatomide-induced Ca²⁺ influx was confirmed by Mn²⁺-induced quench of fura-2 fluorescence. In a Ca²⁺-free medium, preincubation with the endoplasmic reticulum Ca²⁺ pump inhibitor thapsigargin inhibited oxatomide-evoked [Ca²⁺]_i rises. Conversely, treatment with oxatomide abolished thapsigargin-induced [Ca²⁺]_i rises. Inhibition of phospholipase C (PLC) with U73122 also inhibited oxatomide-caused [Ca²⁺]_i rises.

Conclusion: In IMR-90 cells, oxatomide-induced cytotoxicity by preceding [Ca²⁺]_i rises involving PKC-sensitive store-operated Ca²⁺ entry and PLC-dependent Ca²⁺ release from the endoplasmic reticulum. BAPTA-AM, with its Ca²⁺ chelating effects, may be a potential compound for preventing oxatomide-induced cytotoxicity.

The synthetic nitro-alcohol 2-nitro-1-phenyl-1-propanol (NPP) has endothelium-independent relaxing properties in isolated preparations of rat aorta and mesenteric artery. In this study, we investigated whether the vasodilator effects occur in coronary vessels and explored whether hyperpolarization is involved in the underlying mechanism of NPP-induced smooth muscle relaxation. The relaxing responses were studied in isolated preparations of the left anterior descending coronary (ADC) and the septal coronary (SC) arteries, which had been previously maintained under sustained contraction induced by the thromboxane A₂ analogue U-46619. Administered cumulatively, NPP elicited concentration-dependent vasorelaxation with similar potency in both vessels. The relaxant effect remained unaffected by the nitric oxide synthase inhibitor L-NAME, the protein kinase C inhibitor bisindolylmaleimide IV and the Rho-associated protein kinase inhibitor Y-27632. However, it was significantly diminished by the adenylyl cyclase inhibitor MDL-12,330A, the guanylyl cyclase inhibitor ODQ, as well as the K⁺ channel inhibitors tetraethylammonium and CsCl. In ADC preparations impaled with intracellular micropipettes, NPP hyperpolarized the vascular preparation. When the isolated preparation was precontracted by 5-hydroxytryptamine or 80 mM KCl, NPP-induced relaxation with lower pharmacological potency compared to the vessels contracted by U-46619. In conclusion, NPP exhibits vasorelaxant effects on rat coronary arteries, likely involving pathways that include cyclic nucleotide production and membrane hyperpolarization.

Hepatocellular carcinoma (HCC) continues to be the most prevalent type of liver cancer worldwide. Diethylnitrosamine (DEN)-induced HCC is an extensively used hepatic cancer model in experimental animals. Acetazolamide (AZA) is a carbonic anhydrase enzyme inhibitor. This study aimed to assess the therapeutic mechanism of AZA against DEN-induced HCC. Thirty male Wistar albino rats were divided equally into three groups. Group I (C): control group, Group II (HCC): DEN-induced HCC, and Group III (HCC/AZA): AZA-treated HCC. Verification of the HCC induced by DEN was confirmed by elevated liver enzymes' activities, and increased α-fetoprotein (AFP) levels, as well as distinct liver architecture changes. On the other hand, the AZA-treated HCC group experienced decreases in the activities of serum liver enzymes and AFP levels, as well as, regulated liver architecture. Additionally, it downregulated p-p38 MAPK/p-JNK1/JNK2/p-C-Jun/p-NF-κB p65 protein expressions. Moreover, it ameliorated autophagy by controlling the expression of the p-AMPK/p-mTOR1/LC3 I/II proteins. Furthermore, it downregulated the relative gene expressions of carbonic anhydrase-IX (CAIX) and hexokinase-II (HKII). Histopathological examination of AZA-treated HCC liver tissues supported these findings. Conclusion: AZA provides a new dimension in ameliorating experimentally induced HCC through regulation of hepatic biomarkers, antioxidant status, inflammatory markers, and autophagy, mediated by amelioration of CAIX and HKII gene expressions.