复方中药白龙对G1期人胃癌细胞中抑癌基因的影响及与PKA信号通路的相关性

目的：探讨复方中药白龙对人胃癌ＢＧＣ８２－３Ｇ１期细胞周期蛋白激酶抑制因子（ＣＫＩ）ｐ１６＾ＩＮＫ４ａ，ｐ２１以及Ｒｂ，ｃ－ｍｙｃ等基因转录的影响和ｃＡＭＰ－ＰＫＡ信号通路的调节关系。方法：通过实验室常规分子生物学手段（细胞同步化，分子杂交－Ｎｏｒｔｈｅｒｎ杂交，Ｗｅｓｔｅｒｎ杂交等）检测相关基因的表达变化。     

Shikonin induces cell cycle arrest in human gastric cancer (AGS) by early growth response 1 (Egr1)-mediated p21 gene expression

Ethnopharmacological relevance

Lithospermum erythrorhizon, a naphthoquinone compound derived from a shikonin, has long been used as traditional Chinese medicine for treatment of various diseases, including cancer. To evaluate the cytotoxic effects of shikonin on AGS gastric cancer cells via induction of cell cycle arrest.

Materials and methods

We observed the effects of 12.5–100 ng/mL dosage of shikonin treatment on AGS cancer cell line with the incubation time of 6 h. Cytotoxic effects were assessed by measuring the changes in the intracellular ROS, appearance of senescence phenotype, cell cycle progression, CDK and cyclins expression levels upon shikonin treatment. We also examined upon the activation of Egr1-mediated p21 expression, by siRNA transfection, Luciferase assay, and ChIP assay.

Results

In this study, we found that shikonin inhibits cell proliferation by arresting cell cycle progression at the G2/M phase via modulation of p21 in AGS cells. Also, our results revealed that the p21 gene was transactivated by early growth response1 (Egr1) in response to the shikonin treatment. Transient Egr1 expression enhanced shikonin-induced p21 promoter activity, whereas the suppression of Egr1 expression by small interfering RNA attenuated the ability of shikonin to induce p21 promoter activity.

Conclusion

Our results suggested that the anti-proliferative activity of shikonin was due to its ability to induce cell cycle arrest via Egr1–p21 signaling pathway. Thus, the work stated here validates the traditional use of shikonin in the treatment of cancer.     

Anti-angiogenic action of 5,5-diphenyl-2-thiohydantoin-N10 (DPTH-N10)

Previously, we demonstrated that 5,5-diphenyl-2-thiohydantoin (DPTH) exerts an anti-proliferation effect on subcultured human umbilical vein endothelial cells (HUVEC). In the present study, we show that 2(naphthalen-2-ylmethylsulfanyl)-5,5-diphenyl-1,5-dihydro-imidazol-4-one (DPTH-N10), a derivative compound of DPTH, exerts a 5 times stronger inhibition of [3H]thymidine incorporation into HUVEC as compared with DPTH and at very low concentrations (0-20 microM) inhibited DNA synthesis and decreased cell number in cultured HUVEC in a concentration- and time-dependent manner, but not in human fibroblasts. [3H]thymidine incorporation analysis demonstrated that treatment of HUVEC with DPTH-N10 arrested the cell at the G0/G1 phase of the cell cycle. Western blot analysis revealed that the protein level of p21 in HUVEC increased after DPTH-N10 treatment. In contrast, the protein levels of p27, p53, cyclins A, D1, D3 and E, cyclin-dependent kinase (CDK)2, and CDK4 in HUVEC were not changed significantly after DPTH-N10 treatment. Immunoprecipitation showed that the formation of the CDK2-p21 complex, but not the CDK2-p27, CDK4-p21, and CDK4-p27 complex, was increased in the DPTH-N10-treated HUVEC. Kinase assay further demonstrated that CDK2, but not CDK4, kinase activity was decreased in the DPTH-N10-treated HUVEC. Pretreatment of HUVEC with a p21, but not p27, antisense oligonucleotide reversed the DPTH-N10-induced inhibition of [3H]thymidine incorporation into HUVEC. Taken together, these data suggest that DPTH-N10 inhibits HUVEC proliferation by increasing the level of p21 protein, which in turn inhibits CDK2 kinase activity, and finally interrupts the cell cycle. Capillary-like tube formation, aortic ring culture, and chick embryo chorioallantoic membrane (CAM) assays further demonstrated the anti-angiogenic effect of DPTH-N10.     

Anti-proliferation effect of 3-amino-2-imino-3,4-dihydro-2H-1,3-benzothiazin-4-one (BJ-601) on human vascular endothelial cells: G0/G1 p21-associated cell cycle arrest

The aim of this study was to examine the anti-proliferation effect of 3-amino-2-imino-3,4-dihydro-2H-1,3-benzothiazin-4-one (BJ-601) on human vascular endothelial cells and its possible molecular mechanism underlying. Our data showed that BJ-601 at a range of concentrations (0-40 microM) dose- and time-dependently decreased cell number in cultured human dermal microvascular endothelial cells (HDMVECs), but not human fibroblasts. The BJ-601-induced growth inhibition in HDMVECs was reversible. [3H]thymidine incorporation demonstrated that BJ-601 arrested the HDMVECs at the G0/G1 phase of the cell cycle. Western blot analysis revealed that BJ-601 (0-40 microM) dose-dependently increased the levels of the protein p21, but not of p27, p53, cyclins A, D1, D3 and E, cyclin-dependent kinase 2 (CDK2), and CDK4 in HDMVECs. Immunoprecipitation showed that the formation of the CDK2-p21 complex, but not CDK2-p27, CDK4-p21 and CDK4-p27 complexes, was increased in the BJ-601-treated HDMVECs. Kinase assay further demonstrated that CDK2, but not CDK4, kinase activity was decreased in a dose-dependent manner in the BJ-601-treated HDMVECs. Pretreatment of HDMVECs with a p21 antisense oligonucleotide, which blocked the expression of p21 protein, reversed the BJ-601-induced inhibition of [3H]thymidine incorporation into HDMVECs. Moreover, cotreatment of the endothelial cells with protein kinase C (PKC) inhibitor, staurosporine, prevented the BJ-601-induced decrease of [3H]thymidine incorporation into HDMVECs. Administration of BJ-601 dose-dependently inhibited capillary-like tube formation of HDMVECs in Matrigel. In conclusion, these data suggest that BJ-601 inhibits HDMVECs proliferation by increasing the level of p21 protein, which in turn inhibits CDK2 kinase activity, and finally causes retardation of the cell cycle at the G0/G1 phase.     

A systematic review and meta-analysis on the efficacy of Compound Kushen Injection in 3 kinds of digestive tract tumor

BackgroundChemotherapy has become the main means to prolong the life of patients with advanced digestive tract cancer; however, it is associated with serious toxicity and side effects. Compound Kushen Injection (CKI) is a pure Chinese herbal preparation, which can assist chemotherapy, inhibit tumor cell proliferation, and reduce adverse reactions of chemotherapy. In this study, we systematically evaluated reports of CKI as an adjuvant to chemotherapeutic treatment of digestive tract cancer in recent years and provided evidence for clinical diagnosis and treatment.MethodsThe databases of PubMed, Chinese Biomedical Literature (CBM), China National Knowledge Infrastructure (CNKI) and Web Of Science were searched for clinical randomized controlled trials (RCTs) related to adjuvant chemotherapy with CKI in the treatment of advanced gastrointestinal tumors published from January 2000 to September 2021. After screening the qualified literatures, RevMan 5.4 software was used to evaluate the bias of the included literatures and perform meta-analysis.ResultsA total of 12 articles were included in the selection, incorporating 1080 study participants in all; meta-analysis results showed that application of the CKI in the process of chemotherapy for digestive tract tumors could improve the efficacy [odds ratio (OR) =3.11; 95% confidence interval (CI): 2.26 to 4.47, Z=7.00, P<0.00001], increase the patients’ median survival time (months) (OR =3.00; 95% CI: 1.47 to 4.52, Z=3.84, P=0.0001), increase the level of CD3⁺ [mean difference (MD) =4.11; 95% CI: 3.24 to 4.98], CD4⁺ level (MD =8.24; 95% CI: 3.72 to 12.76), reduce the CD8⁺ level (MD =−5.42; 95% CI: −8.09 to −2.76), reduce the tumor markers carcinoembryonic antigen (CEA; MD =−14.26; 95% CI: −14.81 to −13.71), CA199 (MD =−138.87; 95% CI: −143.21 to −132.52), and reduce the adverse reactions of chemotherapy: leukopenia (OR =0.28; 95% CI: 0.19 to 0.43), thrombocytopenia (OR =0.38; 95% CI: 0.24 to 061), decreased hemoglobin (OR =0.55; 95% CI: 0.31 to 0.98), and nausea and vomiting symptoms (OR =0.35; 95% CI: 0.24 to 0.53).DiscussionAdjuvant chemotherapy with CKI in the treatment of digestive tract tumors can effectively improve the symptoms of patients, improve immunity, reduce the level of serum tumor markers, improve efficacy, and reduce toxic and side effects.     

Cip/Kip Cell-cycle Inhibitors: A Neuro-oncological Perspective

The cell cycle is a precisely controlled cellular program that ensures normal cellular proliferation and development. The cyclin-dependant kinases (CDK) are molecules central to the continued progression through the cell-cycle checkpoints and as such are regulated by various mechanisms including cyclin levels, phosphorylation/dephosphorylation and cyclin-dependant kinase inhibitors (CKI). The CKIs are grouped into two families based on their structure and function, four Ink4 CKIs and three Cip/Kip CKIs. Abnormalities in these proteins can give rise to developmental defects and cancer. In this review, we will discuss the biochemistry and cell biology of the each of the Cip/Kip CKIs, their role in development as evidenced by targeted mutations in mice, and their role as possible tumor suppressor genes.     

Pleiotropic effects of selective CDK inhibitors on human normal and cancer cells

Escape from the proper control of the cell cycle by up-regulation of cyclins or aberrant activation of cyclin-dependent kinases (CDKs) as well as by inactivation of cellular inhibitors of CDKs (CKI) leads to malignant transformation. Loss of cellular CKIs in cancers provided a rationale for development of pharmacological inhibitors of CDKs. Recently synthesized CKIs, e.g., purine derivatives such as olomoucine (OLO) and roscovitine (ROSC) are non-genotoxic and exhibit increased selectivity towards CDK2 and CDK7/9. Interestingly, both drugs induce additional effects. Recently, a new, unexpected action of OLO on normal human cells was observed. OLO strongly up-regulates CLIMP-63, a 65 kD protein that mediates the anchoring of the ER to microtubules. Moreover, ROSC induces in human MCF-7 cells phosphorylation of p53 protein at Ser-46 which in turn initiates caspase-independent apoptosis.In the present contribution we raised the question whether both CKIs would be able to block cell cycle progression and to reactivate p53 protein in human HPV-positive HeLa cervix carcinoma cells. We also addressed the question whether exponentially growing cancer cells are more susceptible to the inhibitory action of CKIs than normal cells. Our results show that HeLa cells are much more sensitive to ROSC than normal fibroblasts. ROSC induces G₂ arrest and apoptosis in HeLa cells. It also reactivates and stabilizes wt p53 protein. The increase of p53 protein coincides with down-regulation of E6 oncoprotein.Thus, the biological action of substituted purines is not restricted to the inhibition of CDKs and open new perspectives for their therapeutic applications.     

CKIs对人乳腺癌细胞侵袭转移的影响

目的利用CKI肽类似物抑制CDK激酶活性,以明确CKI对人乳腺癌细胞的作用,探讨其对乳腺癌细胞体外侵袭转移的影响。方法利用作用于CDK4／CDK6的CKI肽类似物p20和p21,分别干预人乳腺癌MDA-MB-231细胞株24h。然后应用细胞与纤维连结蛋白黏附实验测定肿瘤细胞黏附率,通过单层细胞划痕实验观察细胞转染前后迁移能力的变化,Transwell侵袭实验检测细胞体外侵袭力。结果人乳腺癌MDA-MB-231细胞株经CKI肽类似物p20和p21分别干预后,细胞黏附、迁移及侵袭能力明显减弱。结论 CDK4/CDK6激酶对乳腺癌侵袭转移过程具有重要的作用。CKI肽类似物可以抑制乳腺癌MDA-MB-231细胞的黏附、侵袭和迁移。因此CKI肽类似物可能阻抑肿瘤细胞的转移,显示此类细胞穿膜肽在恶性肿瘤治疗上的潜在作用。     

Transgenic expression of cyclooxygenase-2 in mouse intestine epithelium is insufficient to initiate tumorigenesis but promotes tumor progression

This study was aimed at understanding the effect of smoking on pRb phosphorylation and the clinicopathological significance of phospho-pRb in non-small cell lung cancers (NSCLCs). Phospho-pRb (Ser-807/811) expression was not detected in 149 (39%) of 382 patients, and the mean phospho-pRb (Ser-807/811) level was 5.7%. Squamous cell carcinoma had higher phospho-pRb (Ser-807/811) levels than adenocarcinoma (7.1%+/-10.4% versus 4.7%+/-7.9%; P=0.003). The association between phospho-pRb (Ser-807/811) levels and exposure to tobacco smoke was different according to the statuses of cyclin D1 expression and p16 methylation, suggesting that their statuses might play a role as an effect modifier in the relationship between phospho-pRb (Ser-807/811) levels and exposure to tobacco smoke. In stratified multivariate analysis, phospho-pRb (Ser-807/811) levels were not associated with exposure to tobacco smoke in 38 patients with p16 hypermethylation and cyclin D1 expression >5%, after adjusting for confounding factors. However, in the remaining 344 patients, the mean phospho-pRb (Ser-807/811) levels in patients who had smoked >40 pack years increased by 4.65% (P<0.0001) on average than those who had never smoked. No association was found between the phospho-pRb (Ser-807/811) levels and overall survival. In conclusion, the present study suggests that exposure to tobacco smoke is associated with phosphorylation of pRb in NSCLC patients and its relationship depends on the p16 methylation status and cyclin D1 expression levels.