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Objective To determine the protein expression levels of Connexin32 （Cx32）, phosphorylated-Src （p-Src） Y416, total Src, phosphorylated-FAK （p-FAK） Y925 and total FAK in the hepatocellular carcinoma （HCC） tissues, and to evaluate the effect of these proteins on prognosis of HCC patients after hepatectomy. Methods HCC and corresponding paracancerous tissues of patients who underwent radical operation from January 2014 to December 2014 were collected. The protein expression levels of Cx32, p-Src Y416, total Src, p-FAK Y925 and total FAK were measured by immunohistochemistry. Postoperatively, HCC patients were followed up for 5 years. Univarivate and multivariate Cox’s regression analyses were employed to identify the influencing factors of postoperative mortality, and kaplan-Meier curve was delineated to evaluate the survival rate. Results Immunohistochemistry showed that the positive protein expression rate of Cx32 in the HCC tissues was significantly lower, whereas the positive protein expression rates of p-Src Y416, total Src, p-FAK Y925 and total FAK were significantly higher compared with those in the corresponding paracancerous tissues （all P < 0.05）. Univarivate Cox’s regression analysis indicated that age, degree of tumor differentiation, tumor diameter, Cx32, p-Src Y416, total Src, p-FAK Y925 and total FAK were eight suspected influencing factors of postoperative mortality of HCC patients （all P < 0.05）. Multivariate Cox’s regression analysis and survival analysis showed that Cx32 protein expression could be an independent protective factor of postoperative mortality for HCC patients, whereas high protein expression levels of p-Src Y416 and p-FAK Y925 were the independent risk factors （all P < 0.05）. Conclusion Cx32 expression reduces the mortality risk of HCC patients after radical operation, while high expression levels of p-Src Y416 and p-FAK Y925 enhance postoperative mortality risk.

Cysteine-scanning mutagenesis combined with thiol reagent modification is a powerful method with which to define the pore-lining elements of channels and the changes in structure that accompany channel gating. Using the Xenopus laevis oocyte expression system and two-electrode voltage clamp, we performed cysteine-scanning mutagenesis of several pore-lining residues of connexin 26 (Cx26) hemichannels, followed by chemical modification using a methanethiosulfonate (MTS) reagent, to help identify the position of the gate. Unexpectedly, we observed that the effect of MTS modification on the currents was reversed within minutes of washout. Such a reversal should not occur unless reducing agents, which can break the disulfide thiol-MTS linkage, have access to the site of modification. Given the permeability to large metabolites of connexin channels, we tested whether cytosolic glutathione (GSH), the primary cell reducing agent, was reaching the modified sites through the connexin pore. Inhibition of gamma-glutamylcysteine synthetase by buthionine sulfoximine decreased the cytosolic GSH concentration in Xenopus oocytes and reduced reversibility of MTS modification, as did acute treatment with tert-butyl hydroperoxide, which oxidizes GSH. Cysteine modification based on thioether linkages (e.g., maleimides) cannot be reversed by reducing agents and did not reverse with washout. Using reconstituted hemichannels in a liposome-based transport-specific fractionation assay, we confirmed that homomeric Cx26 and Cx32 and heteromeric Cx26/Cx32 are permeable to GSH and other endogenous reductants. These results show that, for wide pores, accessibility of cytosolic reductants can lead to reversal of MTS-based thiol modifications. This potential for reversibility of thiol modification applies to on-cell accessibility studies of connexin channels and other channels that are permeable to large molecules, such as pannexin, CALHM, and VRAC.

Echinocystic acid (EA), a natural triterpone enriched in various herbs, has been showed to have cytotoxic activity in some cancer cells, and is used for medicinal purpose in many Asian countries. In the present study, we found that EA could induce apoptosis in human HepG2 cells, as characterized by DNA fragmentation, activation of caspase-3, -8, and -9, and PARP cleavage. The efficacious induction of apoptosis was observed at 45μM for 24h. Molecular data showed that EA induced the truncation of Bid protein and reduction of Bcl-2 protein. EA also caused the loss of mitochondrial membrane potential (ΔΨm) and cytochrome c release from mitochondria to cytosol. Moreover, EA could activate c-Jun NH2-terminal kinase (JNK) and p38 kinase, and JNK-specific inhibitor SP600125 and p38 kinase-specific inhibitor SB200235 could block serial molecular events of EA-induced apoptosis such as Bid truncation, Bcl-2 reduction, cytochrome c release, caspase activation, and DNA fragmentation in HepG2 cells. These findings indicate that JNK- and p38 kinase-mediated mitochondrial pathways might be involved in EA-induced apoptosis and enhance our understanding of the anticancer function of EA in herbal medicine. [Copyright &y& Elsevier]

Background: PARP inhibitors (PARPi) have been licensed for the maintenance therapy of patients with metastatic pancreatic cancer carrying pathogenic germline BRCA1/2 mutations. However, mutations in BRCA1/2 are notably rare in pancreatic cancer., Objective: There is a significant unmet clinical need to broaden the utility of PARPi., Design: RNA sequencing was performed to screen potential targets for PARPi sensitivity. The synthetic lethal effects were verified in patient-derived xenograft (PDX), xenograft and patient-derived organoid models. Mechanisms were explored via LC‒MS/MS, coimmunoprecipitation, laser microirradiation, immunofluorescence, the homologous recombination (HR) or non-homologous end joining (NHEJ) reporter system, in situ proximity ligation assay and live-cell time-lapse imaging analyses., Results: Targeting protein for Xenopus kinesin-like protein 2 (TPX2) is an exploitable vulnerability. TPX2 was downregulated in PDX models sensitive to PARPi, and TPX2 inhibition conferred synthetic lethality to PARPi both in vitro and in vivo . Mechanistically, TPX2 functions in a cell cycle-dependent manner. In the S/G2 phase, ATM-mediated TPX2 S634 phosphorylation promotes BRCA1 recruitment to double-strand breaks (DSBs) for HR repair, whereas non-phosphorylated TPX2 interacts with 53BP1 to recruit it for NHEJ. The balance between phosphorylated and non-phosphorylated TPX2 determines the DSB repair pathway choice. During mitosis, TPX2 phosphorylation enhances Aurora A activity, promoting mitotic progression and chromosomal stability. Targeting TPX2 S634 phosphorylation with a cell-penetrating peptide causes genomic instability and mitotic catastrophe and enhances PARPi sensitivity. Additionally, the inhibition of TPX2 or S634 phosphorylation combined with gemcitabine further sensitised pancreatic cancer to PARPi., Conclusions: Our findings revealed the dual-functional significance of TPX2 in controlling DNA DSB repair pathway choice and mitotic progression, suggesting a potential therapeutic strategy involving PARPi for patients with pancreatic cancer., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: To investigate the effect of down-regulation of pannexin 2 (Panx-2) channels on cisplatin-induced apoptosis in I-10 cells., Methods: The expression of Panx-2 protein in testicular cancer cells was detected with Western blotting. The testicular cancer cell line I-10 was transfected with two short hairpin RNA (shRNA1 and shRNA2) via Lipofectamine 2000 , the empty vector (NC group) or Lipofectamine2000 (blank control group), and the changes in the expression of Panx-2 was detected with Western blotting. The effects of transfection with a Panx-2 inhibitor on surviving fraction of the cells treated with cisplatin (16 μmol/L) for 24 h, 48 h and 72 h was assessed with MTT assay, and the clonogenic capacity of the cells was evaluated with colony-forming assay. At 8 h after incubation with 16 μmol/L cisplatin, AnnexinV/PI double staining was used to detect the early apoptosis of the cells. After 24 h of treatment with 16 μmol/L cisplatin, the cells were examined for expressions of caspase-3, Bcl-2 and Bax using Western blotting., Results: The expression of Panx-2 was significantly increased in cisplatin-resistant I-10/DDP ( P &lt; 0.001) cells and Tcam-2/DDP ( P &lt; 0.01) cells as compared with I-10 cells and Tcam-2 cells. Transfection of I-10 cells with shRNA1 and shRNA2 resulted in significantly decreased Panx-2 expression ( P &lt; 0.05) and significantly reduced cell surviving fraction ( P &lt; 0.001). In the presence of cisplatin, the cells in NC group showed a higher clonogenic efficiency than those in shRNA1 and shRNA2 groups ( P &lt; 0.001). The early-stage apoptosis rate of the cells in shRNA1 and shRNA2 groups were significantly higher than that in NC group ( P &lt; 0.01). Panx-2 knockdown in I-10 cells significantly increased caspase-3 and Bax expressions ( P &lt; 0.05) and significantly decreased the expression of Bcl-2 ( P &lt; 0.01)., Conclusions: Down-regulation of Panx-2 channel enhances cisplatin-induced apoptosis in cultured testicular cancer cells.

Objective: To investigate the protective effects of dexmedetomidine (DEX) against cerebral ischemia/reperfusion (I/R) injury in mice and its relation with mitochondrial fusion and fission., Methods: Male ICR mice were randomly divided into sham-operated group, I/R group, I/R+DEX group and I/R+DEX+dorsomorphin group. Mouse models of cerebral I/R injury were established by modified thread occlusion of the middle cerebral artery. DEX (50 μg/kg) was injected intraperitoneally at 30 min before cerebral ischemia, which lasted for 1 h followed by reperfusion for 24 h. The neurobehavioral deficits of the mice were evaluated based on Longa's scores. The volume of cerebral infarction was detected by TTC staining. The changes in mitochondrial morphology of the brain cells were observed with transmission electron microscopy. Western blotting was performed to detect the expressions of phosphorylated AMP-activated protein kinase (p-AMPK), mitochondrial fusion protein (Mfn2) and mitochondrial fission protein (p-Drp1) in the brain tissues., Results: DEX pretreatment significantly reduced the neurobehavioral score and the percent volume of cerebral infarction in mice with cerebral I/R injury. Treatment with dorsomorphin (an AMPK inhibitor) in addition to DEX significantly increased the neurobehavioral score and the percent volume of cerebral infarction in the mouse models. Transmission electron microscopy showed that DEX obviously reduced mitochondrial damage caused by cerebral I/R injury and restored mitochondrial morphology of the brain cells, and such effects were abolished by dorsomorphin treatment. Western blotting showed that DEX pretreatment significantly increased the expressions of p-AMPK and Mfn2 protein and decreased the expression of p-Drp1 protein in the brain tissue of the mice, and these changes were also reversed by dorsomorphin treatment., Conclusions: Preconditioning with DEX produces protective effects against cerebral I/R injury in mice possibly by activating AMPK signaling to regulate mitochondrial fusion and fission in the brain cells.

Objective: To investigate the effect of connexin43 (Cx43) protein on autophagy in cisplatin (DDP)-resistant testicular cancer I-10 cells., Methods: The expression of Cx43 proteins in testicular cancer I-10 cells and I-10/DDP cells were detected with Western blotting. I-10/DDP cells were transfected with a full- length mouse Cx43 vector (mCx43) via Lipofectamine 2000 , the empty vector or Lipofectamine 2000 (blank control group), and the changes in the expressions of LC3 and p62 proteins were determined with Western blotting. mCherry-GFP-LC3B transfection and transmission electron microscopy were used to analyze the changes in autophagy of the cells with Cx43 overexpression., Results: Cx43 was significantly decreased in I-10/DDP cells compared with I-10 cells ( P &lt; 0.01). Transfection of the I-10/DDP cells with mCx43 vector resulted in significantly increased Cx43 expression in the cells ( P &lt; 0.01) and caused significantly decreased expression of LC3-Ⅱ ( P &lt; 0.01) and increased expression of p62 ( P &lt; 0.05) as compared with the negative control cells. Both transmission electron microscopy and mCherry-GFP-LC3B transfection showed that the number of autophagosomes was obviously reduced in mCx43-transfected cells as compared with the negative control cells., Conclusions: Cx43 inhibits autophagy in cisplatin-resistant testicular cancer I-10 /DDP cells.

Objective: To investigate the effect of SRC kinase inhibitor PP2 on the invasion and metastasis of lung cancer A549 cells and explore its molecular mechanism., Methods: MTT assay was used to evaluate the inhibitory effect of PP2 on the proliferation of A549 cells. Cell scratch and Transwell assays were performed to assess the invasion and metastatic capacity of A549 cells after treatment with 1, 2, 4, 8, and 16 μmol/L PP2 for 24 h. Western blotting was used to detect the expressions of connexin43 (Cx43) and MMP-2 in the cells after small interfering RNA (siRNA)-mediated silencing or overexpression of Cx43; the changes in the cell invasion and metastasis in response to PP2 treatment after Cx43 silencing or overexpression were investigated., Results: MTT assay showed that treatment with PP2 at 2, 4, 8, 16, and 32 μmol/L significantly inhibited the proliferation of A549 cells in a concentration-dependent manner. Treatments with PP2 at 1, 2, 4, 8, and 16 μmol/L for 24 h also concentration-dependently lowered the invasion and metastatic abilities of the cells ( P &lt; 0.05). At 4 and 8 μmol/L, PP2 significantly increased the expression level of Cx43 protein and decreased the expression level of MMP-2 protein. Overexpression of Cx43 significantly enhanced the inhibitory effect of PP2 on the cell invasion and metastasis, and Cx43 silencing significantly attenuated the inhibitory effect of PP2 ( P &lt; 0.05)., Conclusions: PP2 treatment can suppress the invasion and metastasis of A549 cells in vitro possibly by modulating the expression of Cx43.

Objective: To investigate the protective effects of P2X7 receptor (P2X7R) inhibitor against cerebral ischemia/reperfusion (I/R) injury in rats and the possible mechanisms.
 Methods: The neurological deficit of rats was evaluated by Longa score. The infarct volume was examined by 2, 3, 5-triphenyltetrazolium chloride (TTC) staining. The expression levels of extracellular signal-regulated kinase (ERK), phosphorylation extracellular signal-regulated kinas p-ERK), connexin 43 (Cx43), Bax, Bcl-2 and cleaved caspase-3 were detected by Western blot.
 Results: Compared with sham group, the neurobehavioral score (P<0.05) and cerebral infarct volume (P<0.01) of rats in I/R group was increased. Compared with I/R group, brilliant blue G (BBG, the antagonist of P2X7R) or PD98059 (the inhibitor of EKR kinase) could reduce the neurobehavioral score (P<0.01) and cerebral infarct volume significantly (P<0.05). The neurobehavioral score and cerebral infarct volume was further decreased (P<0.05) when rats were treated with both BBG and PD98059. Compared with I/R group, the expression levels of p-ERK, Cx43, cleaved caspase-3 and the ratio of Bax/Bcl-2 were decreased by BBG or PD98059 pretreatment, and the protective effects were further enhanced when rats were treated with both BBG and PD98059 (P<0.05).
 Conclusion: Inhibition of P2X7R reduces the cerebral I/R injury of rats. ERK inhibition is probably involved in the protective effects of P2X7R inhibitor against cerebral I/R injury, which may be related to the reduction of Cx43 and cleaved caspase-3, and the ratio of Bax/Bcl-2.

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.

Gap junctions (GJs) serve the principal role in the antineoplastic (cytotoxicity and induced apoptosis) effect of chemical drugs. The aim of the present study was to determine the effect of GJ intercellular communication (GJIC) composed of connexin 43 (Cx43) on adriamycin cytotoxicity in breast cancer cells. Four cell lines (Hs578T, MCF-7, MDA-MB-231 and SK-BR-3) with different degree of malignancy were used in the study. The results of western blotting and immunofluorescence revealed that, in Hs578T and MCF-7 cells, which have a low degree of malignancy, the expression levels of Cx43 and GJIC were higher than those in MDA-MB-231 and SK-BR-3 cells (which have a high degree of malignancy). In Hs578T and MCF-7 cells, where GJ could be formed, the function of GJ was modulated by a pharmacological potentiators [retinoid acid (RA)]/inhibitors [oleamide and 18-α-glycyrrhetinic acid (18-α-GA)] and small interfering RNA (siRNA). In high-density cells (where GJ was formed), enhancement of GJ function by RA increased the cytotoxicity of adriamycin, while inhibition of GJ function by oleamide/18-α-GA and siRNA decreased the cytotoxicity caused by adriamycin. Notably, the modulation of GJ did not affect the survival of cells treated with adriamycin when cells were in low density (no GJ was formed). The present study illustrated the association between GJIC and the antitumor effect of adriamycin in breast cancer cells. The cytotoxicity of adriamycin on breast cancer cells was increased when the function of gap junctions was enhanced.

Objective: To compare the biological behaviors of two drug-resistant testicular cancer cell lines established by different methods., Methods: Drug-resistance was induced in testicular cancer cell lines exposure of the cells to increasing concentrations of or a high dose of cisplatin (I-10/DDPi and I-10/DDPh cell lines, respectively). The morphological characteristics of the two cell lines were observed microscopically. The resistance index of the cells was determined with MTT assay, and the cell growth curves were drawn. The cellular expression of resistance-associated proteins MDR1 and P-gp was detected by Western blotting. The cell invasion ability was assessed with Transwell assay., Results: Normal testicular cancer cell line I-10 and the two resistant cell lines all showed an adherent growth pattern. Compared with I-10 cells, I-10/DDP cells exhibited slightly heterogenous cell sizes, irregular shapes, the presence of microvilli tentacles on the cell surface, and a scattered arrangement. The cisplatin resistance index of I-10/DDPi and I-10/DDPh cells were 3.924 and 3.099, respectively. Compared with I-10, the drug-resistant cell lines showed extended doubling time with increased expressions of MDR1 and P-gp and increased cell invasiveness, which was especially obvious in I-10/DDPi cells., Conclusion: Both increasing dose exposure and high-dose exposure to cisplatin can induce cisplatin resistance in testicular cancer cells, and the resistant cells established by the latter method better mimics clinical drug-resistant tumor cells.

Objective: To investigate the protective effect of propofol against focal cerebral ischemia/reperfusion (I/R) injury in rats and its relation with gap junction., Methods: Seventy adult male SD rats were randomly divided into sham-operated group, I/R group, low-, moderate-, and high-dose propofol groups (25, 50, 100 mg/kg; P25, P50, P100 groups, respectively), I/R+CBX group and P100+CBX group. Thread occlusion was used to induce middle cerebral artery occlusion (MCAO) in the mice for 2 h followed by reperfusion for 24 h. Longa's scores were used to evaluate the neurological behavior of the rats. TTC staining was used to measure the cerebral infarction volume and Western blotting was performed to detect the expressions of Cx43, PKC, Bax, and Bcl-2 in the brain of the rats., Results: Compared with the I/R group, the rats pretreated with moderate and high doses of propofol showed significantly reduced neurological behavior scores and cerebral infarction volume percentage, and the effect was more obvious in high-dose propofol pretreatment group. CBX obviously enhanced the protective effect of propofol against I/R injury. Compared with those in the sham-operated group, the protein expression of Cx43 and the Bax/Bcl-2 ratio were increased and the protein expression of PKC was reduced in I/R group, and these changes were significantly reversed by high-dose propofol pretreatment; the effects of propofol were further enhanced by CBX., Conclusion: The protective effect of propofol against cerebral I/R injury may involve the inhibition of the gap junction via PKC signaling and by reducing the Bax/Bcl-2 ratio.

Background and Objective: Cisplatin is a standard first-line chemotherapeutic agents for treating advanced non-small cell lung cancer. Unfortunately, the clinical application cisplatin is restricted because it induces serious adverse reaction. The aim of this study is to investigate the influence and probable mechanism of berberine on cisplatin antineoplastic effect on lung cancer A549 cells., Methods: The total Cx43 protein amount, localization of Cx43 on cell membrane, and gap junction function were observed after the A549 cells were treated with berberine. The influence of berberine on the antitumor action of cisplatin was detected by standard colony-forming assay. Protein kinase C (PKC) protein, which regulates the gap junction, was subsequently determined., Results: Berberine did not affect cell survival at concentrations of 0 μM to 10 μM in the A549 cells. The gap junction function between the cells was enhanced through increased Cx43 protein expression and localization of Cx43 on the membrane after berberine treatment. The intercellular dye coupling through gap junction increased when the cells exposed to 0.1 μM, 1 μM, 10 μM berberine [33.3% (P=0.002,3), 67.0% (P<0.001), 160.0% (P<0.001)] compared withcontrols. This effect was associated with the PKC activity. The cisplatin-induced inhibition of colony growth was enhanced when berberine was combined with cisplatin., Conclusions: Berberine can obviously increase the antitumor effect of cisplatin by enhancing the function of the gap junction possibly in A549 cells.
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Objective: To investigate the effect of Src kinase inhibitor PP2 on hypoxia/reoxygenation (H/R) injury in rat astrocytes in vitro., Methods: In vitro cultured rat astrocytes were exposed to hypoxia for 8 h followed by reoxygenation for 24 h with or without pretreatment with PP2 (10 µmol/L) for 24 h before H/R injury. MTT assay and flow cytometry were used to detect the viability and apoptosis of the exposed astrocytes, respectively, and the protein expressions of Src, Bax, and Bcl-2 in the cells were determined using Western blotting., Results: PP2 pretreatment significantly increased the viability and decreased the apoptosis rate of rat astrocytes exposed to H/R injury (P<0.01). Western blotting showed that H/R injury caused increased expression of Src kinase, which was lowered by PP2 pretreatment. The ratio of Bax/bcl-2 in the astrocytes increased after H/R injury, and was significantly decreased by PP2 pretreatment (P<0.01)., Conclusion: PP2 protects rat astrocytes from H/R injury possibly by inhibiting the expression of Src kinase and activating the anti-apoptotic mechanisms in the cells.

Platinum agents are widely used in the chemotherapy of testicular cancer. However, adverse reactions and resistance to such agents have limited their application in antineoplastic treatment. The aim of the present study was to determine the role of gap junction intercellular communication (GJIC) composed of Cx43 on oxaliplatin‑induced survival/apoptosis in mouse leydig normal and cancer cells using MTT, Annexin V/PI double staining assays and western blot analysis. The results showed that GJIC exerted opposite effects on the mouse leydig cancer (I-10) and normal (TM3) cell apoptosis induced by oxaliplatin. In leydig cancer cells, survival of cells exposed to oxaliplatin was substantially reduced when gap junctions formed as compared to no gap junctions. Pharmacological inhibition of gap junctions by oleamide and 18-α-glycyrrhetinic acid resulted in enhanced survival/decreased apoptosis while enhancement of gap junctions by retinoic acid led to decreased survival/increased apoptosis. These effects occurred only in high‑density cultures (gap junction formed), while the pharmacological modulations had no effects when there was no opportunity for gap junction formation. Notably, GJIC played an opposite (protective) role in normal leydig cells survival/apoptosis following exposure to oxaliplatin. Furthermore, this converse oxaliplatin‑inducing apoptosis exerted through the functional gap junction was correlated with the mitochondrial pathway‑related protein Bcl-2/Bax and caspase‑3/9. These results suggested that in testicular leydig normal/cancer cells, GJIC plays an opposite role in oxaliplatin‑induced apoptosis via the mitochondrial pathway.

Previous studies have shown that irinotecan (CPT‑11) impairs chemotherapy‑induced apoptosis by activating nuclear factor‑κB (NF‑κB) and a number of strategies have been employed to augment chemosensitivity through the suppression of NF‑κB activation. Berberine, a botanical alkaloid, was reported to enhance chemosensitivity to 5‑fluorouracil and doxorubicin by suppressing NF‑κB activation. In the present study, the effect of berberine on CPT‑11‑induced apoptosis was investigated through the inhibition of NF‑κB. Inhibition of NF‑κB activation by p65 small interfering RNA was shown to potentiate apoptosis induced by CPT‑11. Berberine suppressed CPT‑11‑induced NF‑κB activation in a dose‑dependent manner and enhanced chemosensitivity to CPT‑11 by downregulating NF‑κB activation of antiapoptotic genes, c‑IAP1, c‑IAP2, survivin and Bcl‑xL. The current observations indicate that berberine inhibits NF‑κB activation and may be used to enhance CPT‑11‑induced apoptosis in colon cancer.