Role of gap junction intercellular communication in testicular leydig cell apoptosis induced by oxaliplatin via the mitochondrial pathway

The morphological postnatal development of the testis of the Nubian bucks

This study was designed to monitor the morphological development of the reproductive tract of the Nubian bucks in relation to puberty. Thirty-two Nubain male kids were used in the study. The animals were slaughtered at intervals of 2 weeks starting from 1 day old up to 24 weeks of age. Tissue samples were obtained from the testes and processed for ultrastructural studies. The boundary tissue of the newly forming seminiferous tubule adhered closely to the basal lamina. It consisted of a single continuous layer of myoid cells, the outer surface of which was covered by scattered fibroblasts. The ultrastructural study of the boundary of the seminiferous tubule revealed that it consisted of three layers; inner fibrous, middle and outer cellular. The seminiferous tubules at week one were lined by two layers of epithelia; spermatogonia and Sertoli cells in the basal layer, and primary spermatocytes in the second layer. A gradual increase in the diameter of the tubules and epithelial height continued to increase with age. Furthermore, spermatocytes number showed an increase with age. In conclusion, based on the appearance of spermatozoa in the lumina of the seminiferous tubules, puberty age was achieved between weeks 18 and 20.

Effect of berbamine on invasion and metastasis of human liver cancer SMMC-7721 cells and its possible mechanism

Berbamine is a bisbenzylisoquinoline alkaloid extracted from Berberis poiretii of Berberis of Berberidaceae. It has been reported that it can significantly inhibit the proliferation of a variety of malignant tumor cells, including liver cancer. However, the effect of berbamine on the invasion and metastasis of liver cancer has not been reported. The present study demonstrated that berbamine inhibited the migration and invasion of SMMC-7721 cells in a concentration-dependent manner and obviously increased the gap junction function and the expression of Cx32 in SMMC-7721 cells compared with control group. However, after silencing Cx32, berbamine had no significant effect on cell invasion and metastasis. Before silencing Cx32, the expression of PI3K and P-AKT were decreased after berbamine treated on SMMC-7721 cells for 24 h. After silencing Cx32, the expression of PI3K and P-AKT were increased in SMMC-7721 cells. The expression of PI3K and P-AKT had no significant effect after berbamine treated on SMMC-7721 cells for 24 h with silencing Cx32. In conclusion, the results of the present study suggest that berbamine could inhibit the SMMC-7721 cell migration and invasion, and its mechanism may be related to the regulation of PI3K/AKT signaling pathway by enhancing the expression of Cx32.

Genome-Wide Analysis of Low Dose Bisphenol-A (BPA) Exposure in Human Prostate Cells

Endocrine disrupting compounds (EDCs) have the potential to cause adverse effects on wild-life and human health. Two important EDCs are the synthetic estrogen 17α-ethynylestradiol (EE2) and bisphenol-A (BPA) both of which are xenoestrogens (XEs) as they bind the estrogen receptor and dis-rupt estrogen physiology in mammals and other vertebrates. In the recent years the influence of XEs on oncogenes, specifically in relation to breast and prostate cancer has been the subject of considerable study.

[Effect of gap junction modulation on antitumor effects of adriamycin in estrogen receptor-positive breast cancer cells]

OBJECTIVE

To observe the effect of functional modulation of gap junctions (GJ) on the antitumor effect of adriamycin in breast cancer cells positive for estrogen receptor (ER).

METHODS

The inhibitory effect of 0 to 24.0 μmol/L adriamycin on the surviving fraction of ER-positive human breast cancer MCF-7 cells and ER-negative MDA-MB-231 cells was assessed with MTT assay; Western blotting and immunofluorescence assay were used to detect the expressions of Cx43 total protein and membrane protein in the cells. A parachute assay was used to evaluate the function of the GJ in MCF-7 cells. The cytotoxic effect of adriamycin was observed in the cells treated with retinoic acid (RA) for enhancing GJ function, in cells treated with oleamide and 18-α- glycyrrhizic acid (18-α-ga) for inhibiting GJ function, and also in cells transfected with Cx43siRNA for Cx43 knockdown.

RESULTS

ER-positive MCF-7 cells expressed a significantly higher level of Cx43 with stronger GJ function than ER-negative MDA- MB-231 cells. Adriamycin significantly inhibited the proliferation of MCF-7 cells (P < 0.01), and RA treatment further increased the cytotoxicity of adriamycin (P < 0.01) while oleamide and 18-α-GA obviously attenuated the cytotoxicity of adriamycin (P < 0.01). In the cells with Cx43 knockdown, the expressions of total Cx43 protein and Cx43 on the membrane were significantly reduced, the function of GJ was attenuated, and the cytotoxicity of adriamycin was significantly decreased (P < 0.01).

CONCLUSIONS

ER-positive breast cancer cells have stronger Cx43 expressions and GJ function than the ERnegative cells. The cytotoxicity of adriamycin against the breast cancer cells can be strengthened by enhancing GJ function and attenuated by inhibiting GJ function. Cx43 silencing inhibits the function of GJ to lower the cytotoxicity of adriamycin in human breast cancer MCF-7 cells.

In vitro inhibited effect of gap junction composed of Cx43 in the invasion and metastasis of testicular cancer resistanced to cisplatin

The effect of gap junction intercellular communication composed of connexin on cancer invasion/metastasis has been thoroughly explored; however, its effect on testicular cancer resistanced to chemotherapy is still unclear. In this study, we found that the capability of invasion and migration of I-10/DDP (cisplatin (DDP)-resistance) cells were elevated. Furthermore, the expression of Cx43 and the function of gap junction (GJ) in I-10/DDP cells were decreased compared with parental I-10 cells. Pharmacological inhibition of GJs by oleamide (Olea) enhanced invasion and migration. However, enhancement of GJs by retinoic acid (RA) decreased invasion and migration of I-10/DDP cells. To further clarify the invasion/migration inhibited effect of GJ in the testicular cancer resistanced to DDP, GJ function was modulated by overexpression and knockdown of Cx43 expression. Overexpression of Cx43 reduced invasion and migration of I-10/DDP cells. Conversely, knockdown of Cx43 expression increased invasion and migration of I-10/DDP cells. In summary, GJ composed of Cx43 inhibits I-10/DDP cells invasion and migration, and it may become the potential therapeutic target for testicular cancer chemotherapy.

A high-fat diet impairs reproduction by decreasing the IL1β level in mice treated at immature stage

Obesity causes low-grade inflammation that is involved in male infertility. Interleukin 1 beta (IL1β) plays an important role in this process. A high-fat diet (HFD) is the most common cause of obesity. However, the effect of a HFD on IL1β and its consequence in reproduction remain unclear. We established a HFD model in mice treated at immature stage (mice-TIS) and mice treated at mature stage (mice-TMS). Surprisingly, we found that a HFD decreased IL1β levels and was accompanied by an increase in testosterone in mice-TIS, while the reverse results were observed in mice-TMS. In addition, a HFD caused a reduction in testis macrophages and in the expression of inflammasome-related genes and proteins in mice-TIS. Furthermore, we found that IL1β inhibited testosterone secretion through down-regulating the gene expression of P450SCC and P450c17. However, the influence on mice-TIS that were induced by a HFD was recovered by stopping the HFD. In this study, we are the first to report that a HFD impairs the reproductive system by decreasing IL1β and enhancing testosterone levels in mice-TIS, which are different from the effects in mice-TMS. This provides new ideas for the treatment of obesity-induced infertility.

Epithelial-mesenchymal transition plays a critical role in drug resistance of hepatocellular carcinoma cells to oxaliplatin

Drug resistance is one characteristic of hepatocellular carcinoma (HCC) and can affect the prognosis of patients directly. To explore drug resistance well, we established an oxaliplatin (OXA)-resistant cell line Bel-7402/OXA by exposure to gradually increased concentration of OXA. Some biological characters, such as proliferation, migration, and invasion, were studied. Drug sensitivity and the mechanisms of drug resistance were also investigated. We found that the resistant index of Bel-7402/OXA was 8.3. In comparison with Bel-7402, the percentages of cells in S and G2/M phase were increased. The nature apoptosis rate and drug-after apoptosis rate were all decreased in Bel-7402/OXA, as compared to Bel-7402. Bel-7402/OXA acquired increased migration and invasion ability with epithelial-mesenchymal transition (EMT) phenotype. Knockdown of EMT transcription factor Snail could reverse EMT and sensitized Bel-7402/OXA cells to OXA. EMT was one mechanism of drug resistance and may be a novel target of treatment for drug resistance.

[Influence of Berberine on Cisplatin Antineoplastic Effect in A549 Cells]

背景与目的

以顺铂为基础的化疗方案是晚期非小细胞肺癌的一线化疗方案，但是由于顺铂的不良反应严重及耐药性的产生均限制了它的临床应用，本研究采用联合用药的方式观察黄连素对顺铂抗肿瘤作用的影响，并探讨其可能机制。

方法

分别观察黄连素对肺腺癌细胞A549细胞中总Cx43蛋白、细胞膜Cx43蛋白的表达以及细胞缝隙连接功能的改变，通过标准细胞集落克隆实验观察黄连素对顺铂细胞毒性的影响；并观察PKC激酶的表达。

结果

黄连素在0 μM-10 μM浓度范围内对细胞无毒性，通过增加细胞内总Cx43蛋白和胞膜Cx43蛋白的表达而增强细胞缝隙连接功能；这种作用与PKC的活性被抑制相关，抑制PKC活性可以进一步增加顺铂对A549细胞的毒性作用。

结论

黄连素可通过增加A549细胞的缝隙连接功能而明显增强顺铂的细胞毒性。

Tetra-arsenic tetra-sulfide induces cell cycle arrest and apoptosis in retinoic acid-resistant acute promyelocytic leukemia cells

Previous studies have shown that the therapeutic action of tetra-arsenic tetra-sulfide (As₄S₄) is effective for acute promyelocytic leukemia. However, the molecular mechanism of the action of As₄S₄ in retinoic acid-resistant acute promyelocytic leukemia (APL) therapy remains unclear. In the present study, the signaling of the cytotoxic effects induced by As₄S₄ on retinoic acid-resistant APL NB4-R1 cells was investigated. A time-dependent increase in cell death and DNA cleavage was observed following As₄S₄ treatment. Changes in B-cell lymphoma 2 and Bax accompanied by the activation of caspase-3 and cleavage of poly ADP-ribose polymerase were observed as actions of As₄S₄. As₄S₄ induced an accumulation of NB4-R1 cells in the S and G₂/M phases, as detected by flow cytometry. Therefore, the present results suggest that As₄S₄-mediated apoptosis in NB4-R1 cells involves a mitochondria-dependent pathway.