EGFR inhibition reverses epithelial‑mesenchymal transition, and decreases tamoxifen resistance via Snail and Twist downregulation in breast cancer cells

Tamoxifen resistance remains a major obstacle in the treatment of estrogen receptor (ER)‑positive breast cancer. In recent years, the crucial role of the epithelial‑mesenchymal transition (EMT) process in the development of drug resistance in breast cancer has been underlined. However, the central molecules inducing the EMT process during the development of tamoxifen resistance remain to be elucidated. In the present study, it was demonstrated that tamoxifen‑resistant breast cancer cells underwent EMT and exhibited an enhanced cell motility and invasive behavior. The inhibition of snail family transcriptional repressor 1 (Snail) and twist family BHLH transcription factor 1 (Twist) reversed the EMT phenotype and decreased the tamoxifen resistance, migration and invasion of tamoxifen‑resistant breast cancer cells. In addition, it was observed that the inhibition of epidermal growth factor receptor (EGFR) reversed the EMT phenotype in tamoxifen‑resistant MCF7 (MCF‑7/TR) cells via the downregulation of Snail and Twist. Notably, the EGFR inhibitor, gefitinib, decreased tamoxifen resistance, migration and invasion through the inhibition of Snail and Twist. On the whole, the results of the present study suggest that EGFR may be a promising therapeutic target for tamoxifen‑resistant breast cancer. Moreover, it was suggested that gefitinib may serve as a potent novel therapeutic strategy for breast cancer patients, who have developed tamoxifen resistance.

Overactivation of Akt Contributes to MEK Inhibitor Primary and Acquired Resistance in Colorectal Cancer Cells

RAS and BRAF-mutated colorectal cancers are associated with resistance to chemotherapy and poor prognosis, highlighting the need for new therapeutic strategies. Although these cancers sometimes respond to mitogen activated protein kinase kinase (MEK) inhibitor treatment, they often acquire resistance via mechanisms, which are poorly understood. Here, we investigated the mechanism of MEK inhibitor resistance in primary- and acquired-resistant cells. Cell viability was examined using the trypan blue dye exclusion assay. Protein expression was analyzed by western blotting. Somatic mutations in colorectal cancer cells were investigated using the polymerase chain reaction array. PD0325901 and trametinib induced cell death in LoVo and Colo-205 cells but not in DLD-1 and HT-29 cells, which have a PIK3CA mutation constitutively activating Akt and NF-κB. Treatment with PD0325901 and trametinib suppressed ERK1/2 activation in all four cell lines but only induced Akt and NF-κB activation in DLD-1 and HT-29 cells. Inhibition of Akt but not NF-κB, overcame MEK inhibitor resistance in DLD-1 and HT-29 cells. Acquired-resistant LoVo/PR, Colo-205/PR and LoVo/TR cells have constitutively active Akt due to a M1043V mutation in the kinase activation loop of PIK3CA and Akt inhibitor resensitized these cells to MEK inhibitor. These results demonstrate that the overactivation of Akt plays a critical role in MEK inhibitor primary and acquired resistance and implicate combined Akt/MEK inhibition as a potentially useful treatment for RAS/BRAF-mutated colorectal cancer.

Injection of IL-12 gene-transduced dendritic cells into mouse liver tumor lesions activates both innate and acquired immunity

Dendritic cell (DC)-based vaccines have been applied clinically in the setting of advanced-stage cancer. To date, the clinical efficacy of these vaccines has been limited, possibly owing to the impairment of transferred DC function in cancer-bearing patients. In this study, we examined the therapeutic efficacy of interleukin-12 (IL-12) gene-transfected DCs isolated from tumor-bearing hosts against liver tumor. The endogenous DCs isolated from subcutaneous (s.c.) CMS4 tumor-bearing mice (CMS4DC) exhibited decreased expression levels of antigen-presenting molecules and low-allostimulatory capacity. CMS4DC produced less IL-12p70 than DCs isolated from normal mice. Adenoviral transfection of IL-12 gene into CMS4DC (AdIL12DC) restored the expression of antigen-presenting molecules and allostimulatory capacity. Intratumoral (i.t.) delivery of AdIL12DC resulted in complete rejection of intrahepatic CMS4 tumors and activation of innate and acquired immune cells. Antibody depletion studies revealed that both CD4(+) and CD8(+) T cells as well as natural killer cells play critical roles in mediating liver tumor rejection. I.t. treatment of AdIL12DC resulted in long-term protection against s.c. rechallenge with CMS4 tumor cells. These results revealed that IL-12 gene transfer is capable of improving the impaired functions of DC isolated from tumor-bearing hosts, and support the preclinical therapeutic efficacy of intrahepatic injection of AdIL12DC.

A single nucleotide polymorphism of the low molecular mass polypeptide 7 gene influences the interferon response in patients with chronic hepatitis C

Transporter associated with antigen processing (TAP) and low molecular mass polypeptides (LMP) play crucial roles in the human leukocyte antigen (HLA) class I-restricted antigen presenting systems. This study was performed to elucidate whether these antigen-presenting gene polymorphisms could influence the response to interferon (IFN) treatment in patients with chronic hepatitis C. Polymorphisms of TAP and LMP genes in 175 hepatitis C virus (HCV) patients were determined by polymerase chain reaction-restriction fragment length polymorphism. The frequencies of these genes were compared between sustained-responders (n=49) and nonresponders (n=126), classified by biochemical and virological responses to IFN. The distributions of TAP1*, TAP2*, and LMP2 genes between sustained-responders and nonresponders did not differ. However, LMP7-K gene frequency in sustained-responders was higher than that in nonresponders [odds ratio 2.3 (95% confidence interval 1.1-4.6); 16%vs 7.9%]. Multivariate analysis revealed that LMP7-K and HCV-RNA quantity were independent factors influencing the outcome of IFN therapy [4.5 (1.4-14); P=0.011, 0.40 (0.24-0.65); P=0.0003, respectively]. Furthermore, among patients with a low viral load (< or = 2.0 Meq/mL), the LMP7-K positive patients had an even higher ratio of sustained response compared to those without LMP7-K [5.9 (1.6-22); 82%vs 44%; P=0.0062]. These findings suggest that a single nucleotide polymorphism of LMP7 gene is one of the important host factors which independently influence the response to IFN in patients with chronic hepatitis C.

Administration of interleukin-12 enhances the therapeutic efficacy of dendritic cell-based tumor vaccines in mouse hepatocellular carcinoma

Dendritic cells (DCs) are potent antigen-presenting cells that are capable of priming systemic antitumor immune response. Here, we evaluated the combined effectiveness of tumor lysate-pulsed DC immunization and interleukin (IL)-12 administration on the induction of antitumor immunity in a mouse hepatocellular carcinoma (HCC) model. Mouse DCs were pulsed with lysate of BNL 1ME A.7R.1 (BNL), a BALB/c-derived HCC cell line, and then injected into syngeneic mice in combination with systemic administration of IL-12. Lymphocytes from mice treated with BNL lysate-pulsed DCs and IL-12 showed stronger cytolytic activity and produced higher amounts of IFN-gamma than those from mice treated with BNL lysate-pulsed DCs alone. Although immunization with BNL lysate-pulsed DCs alone did not lead to complete regression of established tumors, it significantly inhibited tumor growth compared with vehicle injection. Importantly, the combined therapy of BNL lysate-pulsed DCs and IL-12 resulted in tumor rejection or significant inhibition of tumor growth compared with mice treated with BNL lysate-pulsed DCs alone. In vivo lymphocyte depletion experiments demonstrated that this combination was dependent on both CD8+ and CD4+ T cells, but not natural killer cells. These results demonstrated that IL-12 administration enhanced the therapeutic effect of immunization of tumor lysate-pulsed DCs against HCC in mice. This combination of IL-12 and DCs may be useful for suppressing the growth of residual tumor after primary therapy of human HCC.

Comparison of anesthetic methods for microlaparoscopy in women with unexplained infertility

STUDY OBJECTIVE

To evaluate the effectiveness of ketamine compared with fentanyl as analgesia or sedation for microlaparoscopy.

DESIGN

Prospective, randomized study (Canadian Task Force classification I).

SETTING

University-affiliated hospital.

PATIENTS

Forty-one infertile women.

INTERVENTIONS

Twenty-one patients were randomly assigned to have analgesia with fentanyl and 20 sedation with ketamine during microlaparoscopy. Maximum doses were 0.2 and 200 mg, respectively. Local anesthesia was provided with 0.25% bupivacaine 5 ml injected into cannula sites.

MEASUREMENTS AND MAIN RESULTS

Abnormal findings such as endometriosis and periadnexal adhesions were identified in 24 patients. Ablation, coagulation, and adhesiolysis were easily performed in 14 (82.4%) of 17 women receiving ketamine, but difficulties were encountered in operating on 16 patients receiving fentanyl. Ketamine was administered to 10 patients (47.6%) in the fentanyl group because anxiety and pain were not sufficiently controlled by fentanyl. There were no significant differences in visual analog scale scores and recovery time between groups. On questionnaire, 19 (95%) of 20 patients receiving ketamine indicated they would choose the same anesthesia again if offered, compared with only 4 (19%) of 21 receiving fentanyl (p <0.001).

CONCLUSION

Microlaparoscopy in infertile women was performed more effectively under sedation with ketamine than with fentanyl.