Oxaliplatin was the first platinum drug with proven activity against colorectal tumors, becoming a standard in the management of this malignancy. It is also considered for the treatment of pancreatic ...and gastric cancers. However, a major reason for treatment failure still is the existence of tumor intrinsic or acquired resistance. Consequently, it is important to understand the molecular mechanisms underlying the appearance of this phenomenon to find ways of circumventing it and to improve and optimize treatments. This review will be focused on recent discoveries about oxaliplatin tumor-related resistance mechanisms, including alterations in transport, detoxification, DNA damage response and repair, cell death (apoptotic and nonapoptotic), and epigenetic mechanisms.
Abstract Selecting an adequate model to represent the mass transfer mechanisms occurring in a chromatographic process is generally complicated, which is one of the reasons why monolithic ...chromatography is scarcely simulated. In this study, the chromatographic separation of model proteins bovine serum albumin (BSA), β‐lactoglobulin‐A, and β‐lactoglobulin‐B on an anion exchange monolith was simulated based on experimental parameter determination, simultaneous model testing, and validation under three statistical criteria: retention time, dispersion accuracies, and Pearson correlation coefficient. Experimental characterization of morphologic, physicochemical, and kinetic parameters was performed through volume balances, pressure drop analysis, breakthrough curve analysis, and batch adsorptions. Free Gibbs energy indicated a spontaneous adsorption process for proteins and counterions. Dimensionless numbers were estimated based on height equivalent to a theoretical plate analysis, finding that pore diffusion controlled β‐lactoglobulin separation, whereas adsorption/desorption kinetics was the dominant mechanism for BSA. The elution profiles were modeled using the transport dispersive model and the reactive dispersive model coupled with steric mass action (SMA) isotherms because these models allowed to consider most of the mass transport mechanisms that have been described. RDM‐SMA presented the most accurate simulations at pH 6.0 and at low (250 mM) and high (400 mM) NaCl concentrations. This simulation will be used as reference to forecast the purification of these proteins from bovine whey waste and to extrapolate this methodology to other monolith‐based separations using these three statistical criteria that have not been used previously for this purpose.
To evaluate whether the addition of hydrochlorothiazide (HCTZ) to intravenous furosemide is a safe and effective strategy for improving diuretic response in acute heart failure (AHF).
A prospective, ...double-blind, placebo-controlled trial, including patients with AHF randomized to receive HCTZ or placebo in addition to an intravenous furosemide regimen. The coprimary endpoints were changes in body weight and patient-reported dyspnoea 72 h after randomization. Secondary outcomes included metrics of diuretic response and mortality/rehospitalizations at 30 and 90 days. Safety outcomes (changes in renal function and/or electrolytes) were also assessed. Two hundred and thirty patients (48 women, 83 years) were randomized. Patients assigned to HCTZ were more likely to lose weight at 72 h than those assigned to placebo 2.3 vs. 1.5 kg; adjusted estimated difference (notionally 95 confidence interval) 1.14 (1.84 to 0.42); P 0.002, but there were no significant differences in patient-reported dyspnoea (area under the curve for visual analogue scale: 960 vs. 720; P 0.497). These results were similar 96 h after randomization. Patients allocated to HCTZ showed greater 24 h diuresis (1775 vs. 1400 mL; P 0.05) and weight loss for each 40 mg of furosemide (at 72 and at 96 h) (P 0.001). Patients assigned to HCTZ more frequently presented impaired renal function (increase in creatinine 26.5 moL/L or decrease in eGFR 50; 46.5 vs. 17.2; P 0.001), but hypokalaemia and hypokalaemia were similar between groups. There were no differences in mortality or rehospitalizations.
The addition of HCTZ to loop diuretic therapy improved diuretic response in patients with AHF.
Nanotechnology is one of the most promising technologies of the 21st century, and it is now presenting an enormous impact on target drug delivery. In this context, the recent use of natural ...vesicle‐like nanoparticles such as extracellular vesicles (i.e., exosomes, microvesicles, and apoptotic bodies) and virus‐like particles is rendering encouraging results mostly because these delivery systems present cargo versatility, favorable body circulating advantages, biocompatibility, immunogenicity, and the capacity to be modified superficially to increase their affinity to a certain target or to control their entrance to the cell. However, some of the biggest challenges toward their clinical implementation are poorly standardized processing operations due to their inherent heterogeneity and expensive, long‐lasting, and difficult to scale isolation procedures that can also affect the stability of the particles. Under these circumstances, chromatographic procedures represent an attractive and favorable alternative to overcome their downstream processing. Moreover, even when standardized chromatographic purification protocols are still in development, great achievements have been made using size exclusion, ionic exchange, hydrophobic interaction, and affinity protocols, mostly because of the correct harnessing of the nanovesicle membrane properties. In this sense, this review focuses on presenting the current understanding on the most promising therapeutic biological nanoparticles and the chromatographic isolation approaches employed in their recovery, providing at the same time recent findings and a general overview of the aspects that might impact the outcome of chromatographic techniques for this application.
Resistance to RAF- and MEK-targeted therapy is a major clinical challenge. RAF and MEK inhibitors are initially but only transiently effective in some but not all patients with BRAF gene mutation and ...are largely ineffective in those with RAS gene mutation because of resistance. Through a genetic screen in BRAF-mutant tumor cells, we show that the Hippo pathway effector YAP (encoded by YAP1) acts as a parallel survival input to promote resistance to RAF and MEK inhibitor therapy. Combined YAP and RAF or MEK inhibition was synthetically lethal not only in several BRAF-mutant tumor types but also in RAS-mutant tumors. Increased YAP in tumors harboring BRAF V600E was a biomarker of worse initial response to RAF and MEK inhibition in patients, establishing the clinical relevance of our findings. Our data identify YAP as a new mechanism of resistance to RAF- and MEK-targeted therapy. The findings unveil the synthetic lethality of combined suppression of YAP and RAF or MEK as a promising strategy to enhance treatment response and patient survival.
Summary Background Atrial fibrillation and heart failure often coexist, causing substantial cardiovascular morbidity and mortality. β blockers are indicated in patients with symptomatic heart failure ...with reduced ejection fraction; however, the efficacy of these drugs in patients with concomitant atrial fibrillation is uncertain. We therefore meta-analysed individual-patient data to assess the efficacy of β blockers in patients with heart failure and sinus rhythm compared with atrial fibrillation. Methods We extracted individual-patient data from ten randomised controlled trials of the comparison of β blockers versus placebo in heart failure. The presence of sinus rhythm or atrial fibrillation was ascertained from the baseline electrocardiograph. The primary outcome was all-cause mortality. Analysis was by intention to treat. Outcome data were meta-analysed with an adjusted Cox proportional hazards regression. The study is registered with Clinicaltrials.gov , number NCT0083244 , and PROSPERO, number CRD42014010012. Findings 18 254 patients were assessed, and of these 13 946 (76%) had sinus rhythm and 3066 (17%) had atrial fibrillation at baseline. Crude death rates over a mean follow-up of 1·5 years (SD 1·1) were 16% (2237 of 13 945) in patients with sinus rhythm and 21% (633 of 3064) in patients with atrial fibrillation. β-blocker therapy led to a significant reduction in all-cause mortality in patients with sinus rhythm (hazard ratio 0·73, 0·67–0·80; p<0·001), but not in patients with atrial fibrillation (0·97, 0·83–1·14; p=0·73), with a significant p value for interaction of baseline rhythm (p=0·002). The lack of efficacy for the primary outcome was noted in all subgroups of atrial fibrillation, including age, sex, left ventricular ejection fraction, New York Heart Association class, heart rate, and baseline medical therapy. Interpretation Based on our findings, β blockers should not be used preferentially over other rate-control medications and not regarded as standard therapy to improve prognosis in patients with concomitant heart failure and atrial fibrillation. Funding Menarini Farmaceutica Internazionale (administrative support grant).
Abstract Background In first-line wild-type (WT)-Kirsten rat sarcoma viral oncogene homologue ( KRAS ) metastatic colorectal cancer (mCRC), panitumumab (Pmab) improves outcomes when added to FOLFOX ...folinic acid, 5-fluorouracil, and oxaliplatin or FOLFIRI folinic acid, 5-fluorouracil, and irinotecan. However no trial has directly compared these combinations. Methods Multicentre, open-label study in untreated patients ≥ 18 years with (WT)- KRAS mCRC and multiple or unresectable liver-limited disease (LLD) randomised to either Pmab-FOLFOX4 or Pmab-FOLFIRI. The primary end-point was objective response rate (ORR). Secondary end-points included liver metastases resection rate (R0 + R1), progression-free survival (PFS), overall survival (OS), adverse events and perioperative safety. Exploratory end-points were: response by RAS status, early tumour shrinkage (ETS) and depth of response (DpR) in WT- RAS patients. Results Data on 77 patients were analysed (38 Pmab-FOLFOX4; 39 Pmab-FOLFIRI; WT- RAS : 27/26, respectively). ORR was 74% with Pmab-FOLFOX4 and 67% with Pmab-FOLFIRI (WT- RAS : 78%/73%). Out of the above, 45% and 59% underwent surgical resection, respectively (WT- RAS : 37%/69%). The R0-R1 resection rate was 34%/46% (WT- RAS :26%/54%). Median PFS was 13/14 months (hazard ratio HR Pmab-FOLFIRI versus Pmab-FOLFOX4: 0.9; 95% confidence interval: 0.6–1.5; WT- RAS :13/15; HR: 0.7 0.4–1.3). Median OS was 37/41 months (HR:1.0 0.6–1.8; WT- RAS : 39/49; HR:0.9 0.4–1.9). In WT- RAS patients with confirmed response, median DpR was 71%/66%, and 65%/77% of patients showed ETS ≥ 30%/ ≥ 20% at week 8, without significant differences between arms; these patients had longer median PFS and OS and higher resectability rates. Surgery was associated with longer survival. Perioperative and overall safety were similar, except for higher grade 3/4 neutropenia (40%/10%; p = 0.003) and neuropathy (13%/0%; p = 0.025) in the Pmab-FOLFOX4 arm. Conclusions In patients with WT- KRAS mCRC and LLD, both first-line Pmab-FOLFOX4 and Pmab-FOLFIRI resulted in high ORR and ETS, allowing potentially curative resection. No significant differences in efficacy were observed between the two regimens. (clinicaltrials.gov: NCT00885885 ).
The natural triterpene pristimerin possesses interesting potential against several types of cancer. However, its production at the industrial level requires novel environmentally friendly and ...efficient extraction procedures. Here, we analyze an ethanol–phosphate aqueous two-phase system and the effect of its design parameters such as the tie-line length (TLL) and volume ratio (V R), on the direct extraction of pristimerin. The results showed that a high TLL value of 70% (w/w) and a low V R value of 0.33 allow the obtention of optimal yield and purity values. Partition experiments provided a compound K P value of 3.12 ± 1.21, reaffirming its preference for the ethanol-rich phase. Besides, green assessment positioned the extraction in classification A with 90.93 of 100 points. Furthermore, analysis at different laboratory scales (1×, 10×, and 100×) demonstrated scalability and robustness. Finally, a complete bioprocess based on the obtained results is suggested as a tool to address the pharmaceutical potential of this molecule sustainably and efficiently.
Chemoresistance is the main cause of treatment failure in advanced colorectal cancer (CRC). However, molecular mechanisms underlying this phenomenon remain to be elucidated. In a previous work we ...identified low levels of PKM2 as a putative oxaliplatin-resistance marker in HT29 CRC cell lines and also in patients. In order to assess how PKM2 influences oxaliplatin response in CRC cells, we silenced PKM2 using specific siRNAs in HT29, SW480 and HCT116 cells. MTT test demonstrated that PKM2 silencing induced resistance in HT29 and SW480 cells and sensitivity in HCT116 cells. Same experiments in isogenic HCT116 p53 null cells and double silencing of p53 and PKM2 in HT29 cells failed to show an influence of p53. By using trypan blue stain and FITC-Annexin V/PI tests we detected that PKM2 knockdown was associated with an increase in cell viability but not with a decrease in apoptosis activation in HT29 cells. Fluorescence microscopy revealed PKM2 nuclear translocation in response to oxaliplatin in HCT116 and HT29 cells but not in OXA-resistant HTOXAR3 cells. Finally, by using a qPCR Array we demonstrated that oxaliplatin and PKM2 silencing altered cell death gene expression patterns including those of BMF, which was significantly increased in HT29 cells in response to oxaliplatin, in a dose and time-dependent manner, but not in siPKM2-HT29 and HTOXAR3 cells. BMF gene silencing in HT29 cells lead to a decrease in oxaliplatin-induced cell death. In conclusion, our data report new non-glycolytic roles of PKM2 in response to genotoxic damage and proposes BMF as a possible target gene of PKM2 to be involved in oxaliplatin response and resistance in CRC cells.
PDF
