Toripalimab plus nab-paclitaxel in metastatic or recurrent triple-negative breast cancer: a randomized phase 3 trial.

The combination of immune-checkpoint blockade with chemotherapy for the first-line treatment of advanced triple-negative breast cancer (TNBC) has generated mixed results. TORCHLIGHT is a randomized, double-blinded phase 3 trial evaluating the efficacy and safety of first-line toripalimab and nab-paclitaxel (nab-P) (n = 353; experimental arm) versus placebo and nab-P (n = 178; control arm) for the treatment of women with metastatic or recurrent TNBC. The primary end point was progression-free survival (PFS) assessed by a blinded independent central review in the PD-L1-positive and intention-to-treat populations. The secondary end points included overall survival and safety. Overall, 200 and 100 patients, in the toripalimab and placebo arm respectively had PD-L1-positive TNBC. At the prespecified interim analysis, a statistically significant improvement in PFS assessed by a blinded independent central review was demonstrated in the experimental arm in the PD-L1-positive population (median PFS 8.4 versus 5.6 months; hazard ratio (HR) = 0.65, 95% confidence interval (CI) 0.470-0.906, P = 0.0102). The median overall survival was 32.8 versus 19.5 months (HR = 0.62, 95% CI 0.414-0.914, P = 0.0148). Similar incidences of treatment-emergent adverse events (AEs) (99.2% versus 98.9%), grade ≥3 treatment-emergent AEs (56.4% versus 54.3%) and fatal AEs (0.6% versus 3.4%) occurred in the experimental and control arms. The addition of toripalimab to nab-P provided a significant improvement in PFS for PD-L1-positive patients with metastatic or recurrent TNBC with an acceptable safety profile. ClinicalTrial.gov identifier NCT03777579 .

Association of miR-1247-5p expression with clinicopathological parameters and prognosis in breast cancer.

Our study aimed to clarify the correlation between miR-1247-5p expression and clinicopathological parameters and survival of patients with breast cancer (BC). We evaluated the expression level of miR-1247-5p in 224 formalin-fixed, paraffin-embedded specimens (112 BC and matched cancer free tissues) by quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR). miR-1247-5p expression in BC tissues was found to be decreased compared with matched normal tissues (P < 0.01). Additionally, low miR-1247-5p expression in BC tissues was significantly associated with the advanced TNM stage (P = 0.007), lymph node metastasis (P = 0.015), poorer pathological differentiation (P = 0.005) and molecular subtype (P = 0.027). The patients in the low miR-1247-5p group had a shorter disease-free survival and overall survival than those in the high miR-1247-5p group (P < 0.01). Furthermore, the univariate and the multivariate analyses showed that miR-1247-5p expression was an independent predictor of overall survival (P < 0.01). Our study showed that miR-1247-5p was related to the biological behaviour of breast tumour and prognosis of patients with BC. miR-1247-5p could be a novel tumour suppressor and act as a potential biomarker and therapeutic agent for breast carcinoma.

Ribozyme cleavage leads to decreased expression of fibroblast growth factor receptor 3 in human multiple myeloma cells, which is associated with apoptosis and downregulation of vascular endothelial growth factor.

The aim of this study was to investigate the fibroblast growth factor receptor 3 (FGFR3) mRNA cleavage by ribozymes targeting FGFR3, effect of growth inhibition and associated with mechanism on multiple myeloma (MM). We designated two ribozyme-expressing plasmids that target the FGFR3 genes, Rz52 and Rz32. In vitro catalytic activity of Rz52 and Rz32 in KMS11 cells decreased FGFR3 mRNA expression to 45% (p < 0.05) and 80% (p < 0.5), respectively, of that of the control. In vivo examination of the Rz52-transfected KMS11 clone showed that FGFR3 mRNA expression decreased to 20% (p < 0.05) of the control. In the Rz52-transfected H929 clone, FGFR3 mRNA decreased to 50% of the control. Protein expression of FGFR3 decreased to 70% of the parental KMS11 and H929 clones. DNA synthesis in the Rz52-transfected KMS11 clone decreased to 20% of that of the control, whereas the viability of cells decreased to 2% (p < 0.01) of that of the control. Ribozyme cleavage-associated increase in apoptosis of Rz52 KMS11 transfectants was twice that of the control. The inhibition of FGFR3 expression by ribozymes was associated with decreased vascular endothelial growth factor (VEGF) expression and upregulation of Flt-1 but not of the KDR receptor. Our data indicate that FGFR3 is an important cell survival and antiapoptotic factor for MM cells and that ribozyme-targeted downregulation of FGFR3 might be useful as a novel therapeutic intervention in MM characterized by t(4;14).

The human ribonucleotide reductase subunit hRRM2 complements p53R2 in response to UV-induced DNA repair in cells with mutant p53.

Ribonucleotide reductase (RR) is responsible for the de novo conversion of the ribonucleoside diphosphates to deoxyribonucleoside diphosphates, which are essential for DNA synthesis and repair. RR consists of two subunits, hRRM1 and hRRM2. p53R2 is a new RR family member. Because the majority of human tumors possess mutant p53, it is important to know the molecular mechanism by which mutant p53 regulates RR and to what extent. In this study, we investigated the expression and function of p53R2 and hRRM2 after UV treatment in human prostate cancer PC3 cells, which possess mutant p53 with a truncated COOH-terminal, and in human oropharyngeal cancer KB cells, which possess wild-type p53. p53R2 (analyzed by Western blot and standardized relative to Coomassie Blue-stained band) was down-regulated in PC3 cells and up-regulated in KB cells after UV exposure. In contrast, hRRM2 was up-regulated by UV in both PC3 cells and KB cells. hRRM2 and p53R2 mRNA levels were assessed by Northern blot, and the results paralleled that of the Western blot. Coimmunoprecipitation assays using agarose-conjugated goat antihuman RRM1 antibody confirmed that the p53R2 binding to hRRM1 decreased in PC3 cells but increased in KB cells after UV treatment. hRRM2 binding to hRRM1 increased in both cell lines under the same conditions. These results suggest that PC3 cells are deficient in both transcription of p53R2 and binding to hRRM1 in response to UV irradiation. Confocal microscopy further confirmed that these findings were not due to translocation of hRRM2 and p53R2 from the cytoplasm to the nucleus. RR activity was measured following UV treatment and shown to increase in PC3 cells. It was unchanged in proportional of KB cells. The RR activity is consistent with the expression of hRRM2 seen in the Western blots. Thus, we hypothesize that hRRM2 complements p53R2 to form RR holoenzyme and maintain RR activity in PC3 cells after UV treatment. To further confirm this hypothesis, we examined the effect of RRM2 inhibitors on cells exposed to UV. In PC3 cells, hydroxyurea inhibited hRRM2 and resulted in increased sensitivity to UV irradiation. We also examined the effect of UV treatment on the colony-forming ability of cells transfected with hRRM2 as well as p53R2 sense or antisense expression vectors. Expression of antisense hRRM2 in PC3 cells led to decreased hRRM2 expression and resulted in greater sensitivity to UV than observed in wild-type PC3 cells. Taken together, we conclude that UV-induced activation of p53R2 transcription and binding of p53R2 to hRRM1 to form RR holoenzyme are impaired in the p53-mutant cell line PC3.

Time and sequence dependence of hydroxyurea in combination with gemcitabine in human KB cells.

Gemcitabine (Gem) is a deoxycytidine analogue whose active metabolite, dFdCTP, blocks DNA elongation and has a cytotoxic effect. Hydroxyurea (HU) is an S-phase specific inhibitor of ribonucleotide reductase (RR) with a broad spectrum of antitumor effects. We report here that low-dose HU enhanced the activity of Gem in a time- and sequence-dependent manner. Exposure of human oropharyngeal carcinoma KB cells to HU followed by the addition of Gem at various times significantly enhanced cytotoxicity when compared to controls. The greatest enhancement of cytotoxicity occurred when Gem was added 8 hours after HU. By treating KB cells with radiolabeled-Gem following HU treatment, we further confirmed that the incorporation of dFdCTP into DNA increased 6-fold over control reactions under these conditions. The mechanism of the time- and sequence-dependent enhancement is associated with a decrease in hRRM2 RNA, protein, and activity between 4 and 8 hours. The subsequent depletion of dNTP pools allows for increased incorporation of dFdCTP into cells arrested in S-phase, resulting in higher levels of cytotoxicity than either treatment alone.