The effects of bisphenol S exposure on the growth, physiological and biochemical indices, and ecdysteroid receptor gene expression in red swamp crayfish, Procambarus clarkii.

The experiment was conducted to investigate the effects of Bisphenol S (BPS) on growth, physiological and biochemical indices, and the expression of ecdysteroid receptor (ECR) of the red swamp crayfish (Procambarus clarkii). The gene encoding ECR was isolated from red swamp crayfish by homologous cloning and rapid amplification of cDNA ends (RACE). The ECR transcripts were 1757 bp long and encoded proteins of 576 amino acids. The quantitative real-time PCR (qRT-PCR) analysis showed that the ECR gene was expressed in various tissues under normal conditions, and the highest level was observed in the ovary and the lowest level was observed in the muscle (P < 0.05). Then, the experiment was designed with four different BPS concentrations (0, 1, 10, and 100 µg/L), BPS exposure for 14 days, three parallel groups, and a total of 240 red swamp crayfish. At 100 µg/L BPS, the survival rate, weight gain rate, and relative length rate were decreased significantly (P < 0.05). Malonaldehyde (MDA) content reached the highest level at 100 µg/L BPS. When BPS concentration was higher than 10 µg/L, the activities of superoxide dismutase (SOD) and catalase (CAT) were significantly lower than those of the control group (P < 0.05). The expression levels of the ECR gene in ovary, intestinal, gill, and hepatopancreas tissues were significantly increased after BPS exposure (P < 0.05). The ECR gene expression in ovaries and Y-organs was significantly higher than other groups in 10 µg/L BPS (P < 0.05). The expressions of the tumor necrosis factor -α (TNF-α) and interleukin-6 (IL-6) genes in the hepatopancreas gradually increased, and the highest expression was observed exposed in 100 µg/L BPS (P < 0.05). This research will provide novel insights into the health risk assessment of BPS in aquatic organisms.

Recombinant immunotoxin induces tumor intrinsic STING signaling against head and neck squamous cell carcinoma.

The innate immune stimulator of interferon genes (STING) pathway is known to activate type I interferons (IFN-I) and participate in generating antitumor immunity. We previously produced hDT806, a recombinant diphtheria immunotoxin, and demonstrated its efficacy against head and neck squamous cell carcinoma (HNSCC). However, it's unknown whether the tumor-intrinsic STING plays a role in the anti-HNSCC effects of hDT806. In this study, we investigated the innate immune modulation of hDT806 on HNSCC. hDT806 significantly upregulated the level of STING and the ratio of p-TBK1/TBK1 in the HNSCC cells. Moreover, intratumoral hDT806 treatment increased the expression of STING-IFN-I signaling proteins including IFNA1, IFNB, CXCL10 and MX1, a marker of IFN-I receptor activity, in the HNSCC xenografts. Overexpression of STING mimicked the hDT806-induced upregulation of the STING-IFN-I signaling and induced apoptosis in the HNSCC cells. In the mouse xenograft models of HNSCC with STING overexpression, we observed a significant suppression of tumor growth and reduced tumor weight with increased apoptosis compared to their control xenograft counterparts without STING overexpression. Collectively, our data revealed that hDT806 may act as a stimulator of tumor-intrinsic STING-IFN-I signaling to inhibit tumor growth in HNSCC.

Analysis of the Whole-Genome Sequences from an Equus Parent-Offspring Trio Provides Insight into the Genomic Incompatibilities in the Hybrid Mule.

Interspecific hybridization often shows negative effects on hybrids. However, only a few multicellular species, limited to a handful of plants and animals, have shown partial genetic mechanisms by which hybridization leads to low fitness in hybrids. Here, to explore the outcome of combining the two genomes of a horse and donkey, we analyzed the whole-genome sequences from an Equus parent-offspring trio using Illumina platforms. We generated 41.39× and 46.21× coverage sequences for the horse and mule, respectively. For the donkey, a 40.38× coverage sequence was generated and stored in our laboratory. Approximately 24.86 million alleles were discovered that varied from the reference genome. Single nucleotide polymorphisms were used as polymorphic markers for assigning alleles to their parental genomic inheritance. We identified 25,703 Mendelian inheritance error single nucleotide polymorphisms in the mule genome that were not inherited from the parents through Mendelian inheritance. A total of 555 de novo single nucleotide polymorphisms were also identified. The rate of de novo single nucleotide polymorphisms was 2.21 × 10-7 in the mule from the Equus parent-offspring trio. This rate is obviously higher than the natural mutation rate for Equus, which is also consistent with the previous hypothesis that interracial crosses may have a high mutation rate. The genes associated with these single nucleotide polymorphisms are mainly involved in immune processes, DNA repair, and cancer processes. The results of the analysis of three genomes from an Equus parent-offspring trio improved our knowledge of the consequences of the integration of parental genomes in mules.

Interactions between unfolding/disassembling behaviors, proteolytic subfragments and reversible aggregation of oxidized skeletal myosin isoforms at different salt contents.

Myosin filament plays a critical role in water-trapping and thermodynamic regulation during processing of brined muscle foods. The redox state and availability of proteolytic/antioxidant enzymes affected by salt may change the ion-binding capacity of myosin consequently contributing to swelling and rehydration. Thus, this study investigated the impact of different salt content (0%, 1%, 2%, 3%, 4%, 5% NaCl) and oxidation in vitro (10 mM H2O2/ascorbate-based hydroxyl radical (OH)-generating system) on the oxidative stability, solubility/dispersion capacity, chymotrypsin digestibility, aggregation site and the microrheological properties of isolated porcine myosin. The result showed that, brining at 2% salt exposed more sulfhydryl groups and inhibited the formation of disulfide bond, whereby smaller dispersed structure (diameter within 10-50 nm) and higher Ca2+-ATPase activity of the denatured myosin were observed. Accordingly, gel electrophoresis showed that myosin S1 and HMM subunits were highly oxidized and susceptible to reversible assembles. Despite enhanced hydrophobic interactions between swelled myosin at 3% salt content, ≥4% salt greatly promoted the exposure/polarization of tryptophan and cross-linking structures, mainly occurring at myosin S2 portion. The results of micro-rheology proved that oxidized myosin formed a tighter heat-set network following rehydration at high ion strength (≥4% salt), suggesting an increased inter-droplet resistance and macroscopic viscosity. This work is expected to give some useful insights into improved texture and functionality of engineered muscle foods.

Antitumor Efficacy of EGFR-Targeted Recombinant Immunotoxin in Human Head and Neck Squamous Cell Carcinoma.

Over 90% of head and neck squamous cell carcinoma (HNSCC) overexpresses the epidermal growth factor receptor (EGFR). However, the EGFR-targeted monotherapy response rate only achieves 10-30% in HNSCC. Recombinant immunotoxin (RIT) often consists of an antibody targeting a tumor antigen and a toxin (e.g., diphtheria toxin [DT]) that kills cancer cells. We produced a humanized RIT, designated as hDT806, targeting overexpressed EGFR and investigated its effects in HNSCC. Distinct from the EGFR-targeted tyrosine kinase inhibitor erlotinib or antibody cetuximab, hDT806 effectively suppressed cell proliferation in the four HNSCC lines tested (JHU-011, -013, -022, and -029). In JHU-029 mouse xenograft models, hDT806 substantially reduced tumor growth. hDT806 decreased EGFR protein levels and disrupted the EGFR signaling downstream effectors, including MAPK/ERK1/2 and AKT, while increased proapoptotic proteins, such as p53, caspase-9, caspase-3, and the cleaved PAPR. The hDT806-induced apoptosis of HNSCC cells was corroborated by flow cytometric analysis. Furthermore, hDT806 resulted in a drastic inhibition in RNA polymerase II carboxy-terminal domain phosphorylation critical for transcription and a significant increase in the γH2A.X level, a DNA damage marker. Thus, the direct disruption of EGFR signaling, transcription inhibition, DNA damage, as well as apoptosis induced by hDT806 may contribute to its antitumor efficacy in HNSCC.

Exploring the Meaning in Life and the Influencing Factors among Patients Undergoing Hemodialysis in Macau.

Introduction: The meaning in life (ML) is a significant predictor of the physical and mental health of patients with chronic diseases, and its construct is culturally specific.As a group between normal people and the patients with advanced cancer, patients with End-Stage Kidney Disease (ESKD) who are undergoing hemodialysis (HD) are often outside of research focus on ML. Objectives: This study was to investigate the status of ML of patients on HD in Macau of China and to analyze the influence of social-demographic characteristics and disease-related factors on their ML. The study findings would inform the development of evidence-based interventions in nursing care for this patient population. Methods: This study employed a cross-sectional survey design. Eligible participants were recruited by convenient sampling from the largest HD center in Macau in January 2020. The participants' social-demographic and disease-related characteristics were collected, and their ML status was assessed by the Meaning in Life Scale for Hemodialysis Patients (MLSHP). SPSS 22.0 software was used to analyze the data. Results: Questionnaires were distributed to 249 potential participants who were patients on HD, and 238 patients replied to the questionnaires effectively. The effective response rate was 95.58% (238/249). The average score of ML for the patients was 93.75 ± 10.00, which was 72% of the total score of 130 on the ML scale. Gender, religious belief, duration of dialysis treatment, and symptom-related distress had impacts on ML levels (p < .05), with religious belief being a particularly strong predictor (p < .001). Conclusion: The level of ML for patients on HD in Macau is relatively high. Different demographic or disease-related factors impact participants' ML, supporting or contradicting previous studies. While the study findings are meaningful under the local cultural contexts, they have implications for nurses in other places to develop evidence-based interventions for patients on HD.

Predictive Factors for Failure of Noninvasive Ventilation in Adult Intensive Care Unit: A Retrospective Clinical Study.

Background: Noninvasive ventilation (NIV) has been reported to be beneficial for patients with acute respiratory failure in intensive care unit (ICU); however, factors that influence the clinical outcome of NIV were unclarified. We aim to determine the factors that predict the failure of NIV in critically ill patients with acute respiratory failure (ARF). Setting. Adult mixed ICU in a medical university affiliated hospital. Patients and Methods. A retrospective clinical study using data from critical adult patients with initial NIV admitted to ICU in the period August 2016 to November 2017. Failure of NIV was regarded as patients needing invasive ventilation. Logistic regression was employed to determine the risk factor(s) for NIV, and a predictive model for NIV outcome was set up using risk factors. Results: Of 101 included patients, 50 were unsuccessful. Although more than 20 variables were associated with NIV failure, multivariate logistic regression demonstrated that only ideal body weight (IBW) (OR 1.110 (95%1.027-1.201), P=0.009), the maximal heart rate during NIV period (HR-MAX) (OR 1.024 (1.004-1.046), P=0.021), the minimal respiratory rate during NIV period (RR-MIN) (OR 1.198(1.051-1.365), P=0.007), and the highest body temperature during NIV period (T-MAX) (OR 1.838(1.038-3.252), P=0.037) were independent risk factors for NIV failure. We set up a predictive model based on these independent risk factors, whose area under the receiver operating characteristic curve (AUROC) was 0.783 (95% CI: 0.676-0.899, P < 0.001), and the sensitivity and specificity of model were 68.75% and 71.43%, respectively, with the optimal cut-off value of 0.4863. Conclusion: IBW, HR-MAX, RR-MIN, and T-MAX were associated with NIV failure in patients with ARF. A predictive model based on the risk factors could help to discriminate patients who are vulnerable to NIV failure.

[Analysis of prognostic risk factors of bloodstream infection in intensive care unit patients].

OBJECTIVE: To explore the prognostic risk factors of bloodstream infection (BSI) in intensive care unit (ICU) patients, furthermore, to provide a reliable evidence for early warning and treatment for the critical patients with BSI. METHODS: A retrospective study was performed. The clinical data of patients with blood culture-positive admitted to ICU of the Affiliated Hospital of Guizhou Medical University from January 1 to September 30, 2019 were analyzed. The data including gender, age, proportion of basic diseases, acute physiology and chronic health evaluation II (APACHE II), the duration of mechanical ventilation after being diagnosed with BSI, length of stay in ICU, aggressive operation and blood product infusion after BSI, proportion of using continuous renal replacement therapy (CRRT) and continuous vasoactive agents for more than 72 hours after being diagnosed with BSI, and site of central venous catheterization were recorded. Meantime, the worst laboratory values within 72 hours after being diagnosed with BSI, information about pathogenic microorganism categories and distributions were collected and analyzed. The patients were divided into survival and death groups based on the the 28-day prognosis, and the differences of clinical data between the two groups were compared. Logistic regression analysis was used to select the independent prognostic risk factors of BSI. RESULTS: One hundred and fifty-four patients with positive results of BSI were enrolled, and the 156 strains of bacteria were detected, including 75 Gram positive (G+) bacteria strains, 70 Gram negative (G-) bacteria strains and 11 fungi strains among those BSI patients. The top five pathogenic microorganisms were Coagulase negative staphylococcus (35.9%), Klebsiella pneumonia (12.8%), Acinetobacter baumannii (9.0%), Enterococci (9.0%), and Escherichia coli (8.3%). There were 45 strains (60.0%) of multidrug-resistant strains in G+ bacteria and 40 strains of multidrug-resistant strains (57.1%) in G- bacterial strains, but in fungi there was only 1 strain (9.1%). There were 81 cases in survival group and 73 cases in death group according to 28-day prognosis. We found that there were no significant differences between the comparators in age, lenth of stay in ICU, duration for mechanical ventilation after being diagnosed with BSI, percentage of BSI with chronic obstructive pulmonary disease (COPD), hypertension, cardiovascular disease or chronic kidney dysfunction (all P > 0.05). In death group, the proportion of male was obviously lower than that of survival group [58.9% (43/73) vs. 75.3% (61/81), P < 0.05] and APACHE II score was significantly higher than that in survival group (27.1±7.0 vs. 19.5±6.7, P < 0.05). The mean arterial pressure (MAP) of death group on first 3 days of BSI was significantly lower than that of survival group [mmHg (1 mmHg = 0.133 kPa): 72.8±13.6 vs. 79.7±12.9, P < 0.05), in the death group, the proportion of patients complicated with diabetes, cancer [28.8% (29/73) vs. 12.3% (10/81), 19.2% (14/73) vs. 7.4% (6/81)], post-BSI CRRT and blood transfusion [39.7% (29/73) vs. 16.0% (13/81), 64.4% (47/73) vs. 46.9% (38/81)], and continuous use of asoactie drugs for ≥ 72 hours [37.0% (27/73) vs. 12.3% (10/81)] were significantly higher than those in the survival group (all P < 0.05). In death group, platelet count (PLT) was significantly decreased than that of survival group [×109/L: 124.93±98.21 vs. 181.15±116.39,P < 0.05], aspartate aminotransferase (AST) level was significantly higher than that of survival group [U/L: 75.40 (38.50, 140.95) vs. 56.20 (29.20, 85.70), P < 0.05], the rest of the laboratory indexes had no statistically significant differences between the two groups (all P > 0.05). The results of Logistic regression analysis showed that the APACHE II score [odds ratio (OR) = 1.279, 95% confidence interval (95%CI) was 1.158 to 1.412, P < 0.001], CRRT after BSI (OR = 3.522, 95%CI was 1.013 to 12.245, P = 0.048) were independent risk factors affecting the prognosis of patients with BSI, and MAP is a protective factor for prognosis (OR = 0.961, 95%CI was 0.927 to 0.996, P = 0.031). CONCLUSIONS: In our ICU, G+ bacteria are still dominant in bloodstream infection, G- bacteria take the second place. Besides, APACHE II score and CRRT after being diagnosed with BSI are the independent prognostic risk factors.

[Analysis of prognosis risk factors of critically ill patients after cardiac surgery: a consecutive 5-year retrospective study].

OBJECTIVE: To explore the risk factors affecting prognosis of critically ill patients following cardiac surgery, furthermore, to assess severity and keep alarm earlier. METHODS: A retrospective study was conducted. The clinical data of critically ill patients following cardiac surgery admitted to intensive care unit (ICU) of the Affiliated Hospital of Guizhou Medical University from January 1st 2014 to December 31st 2018 were enrolled. The clinical characteristics, acute physiology and chronic health evaluation II (APACHE II) and the worst laboratory examination within 24 hours after ICU admission, and the duration of mechanical ventilation, length of ICU stay, using continuous renal replacement therapy (CRRT), accepting vasoactive agents such as norepinephrine, dopamine or dobutamine and blood products such as red blood cells, plasma or platelets were recorded. The patients were divided into survival group and dead group based on discharge prognosis, and the difference in clinical data between the two groups was compared. Binary multivariate Logistic regression analysis was used to screen the risk factors affecting the prognosis of critically ill patients following cardiac surgery, and the receiver operating characteristic (ROC) curve was plotted to analyze the predictive value of these risk factors. RESULTS: In total, 97 patients after cardiac operation were admitted to ICU during the five years. Thirty-two patients were excluded owing to age less than 16 years old, no more than 24 hours of the length of ICU stay, without the outcomes of myocardium enzymes or myocardium markers within the first 24 hours or admitted only for pacemaker. Finally, 65 patients met the criteria, with 40 survived and 25 died. Compared with survival group, APACHE II scores, the level of serum uric acid, serum creatinine (SCr), cardiac troponin T (cTnT), brain natriuretic peptide (BNP), procalcitonin (PCT) and the rate of patients accepting CRRT, vasoactive agents and blood products in dead group were significantly increased with significant differences; however, there was no statistically difference in gender, age, body weight index (BMI), distribution of types of cardiac surgery, ratio of patients suffered from hypertension and diabetes, mean arterial pressure (MAP), white blood cell (WBC), coagulation, length of ICU stay, or duration of mechanical ventilation between the two groups. Binary multivariate Logistic regression analysis showed that APACHE II scores [odds ratio (OR) = 1.123, 95% confidence interval (95%CI) = 1.004-1.257, P = 0.043] and cTnT (OR = 1.496, 95%CI = 1.038-2.158, P = 0.031) were the independent risk factors for prognosis of critical ill patients following cardiac surgery. ROC curve analysis showed that APACHE II score and cTnT had predictive value for prognosis of critical ill patients following cardiac surgery, the best was exerted when APACHE II score combined with cTnT, the area under the ROC curve (AUC) was 0.839, the joint prediction probability was 0.42, the sensitivity was 80.0%, and the specificity was 64.0%. CONCLUSIONS: APACHE II score and cTnT may be one of independent risk factors for prognosis of critical ill patients following cardiac surgery, and there will be far more greater predictive value when APACHE II score combined with cTnT.

[Development and construction mode of critical care medicine: 22 years of development and construction of intensive care units of Guizhou Medical University].

OBJECTIVE: To provide decision-making basis for promoting the rapid and healthy development of critical care medicine/intensive care unit (ICU) through discussing the mode of development and construction of the department of ICU. METHODS: The situations of ICU of Affiliated Hospital of Guizhou Medical University from July 1994 to December 2016 were analyzed and summed up. Data of the situations in different development stages included the location and area of the ward, the number of beds, the number of physicians and nurses, the structure of academic titles and educational levels, the number of patients admitted to ICU per year, the proportion of patients used ventilator per year, the mortality, the mode of the discipline management, the number of medical postgraduates and undergraduates trained in the ICU, the number of teaching hours, the achievements, the number of research projects, the number of published monographs and papers, the number of the multicenter trials that we participated in, the construction of the team, the personal honor, and so on. RESULTS: From 1994 to 2016, the department of ICU had three development stages: the initial development stage of the discipline (from July 1994 to March 2005), the standardization development stage of the discipline (from April 2005 to December 2015), the acceleration development stage of the discipline (from December 2015 to December 2016). The scale of the department expanded from an open unit with 6 beds which was shared with the department of cardiothoracic surgery to 6 enclosed units with 90 beds which were managed independently by the intensivists. The area of the department increased from less than 300 m2 to more than 7 000 m2. There were 46 beds in the mixed ICU, which covered an area of 4 210 m2. There was only one physician in 1994 while the number of the physicians increased to 19 in 2016. The number of nurses increased from 4 in 1994 to 69 in 2016. The proportion of highly educated talents significantly increased. Furthermore, from 1994 to 2016, the number of beds increased from 6 to 46; the number of patients admitted to ICU per year increased from 138 to 1 080; and the number of patients used ventilator increased from 24 to 1 057. The mean acute physiology and chronic health evaluation II (APACHE II) score was > 24.0 at admission, while < 12.6 at discharge. From 1997 to 2016, a total of 79 postgraduates had studied in the department, and 390 teaching hours we had undertaken. From 2011 to 2016, a total of 250 undergraduates had studied in the department, and 540 teaching hours we had undertaken. From 1994 to 2016, 8 achievements were obtained, 22 projects were undertook, 4 monographs were published, 6 books were edited that the physicians in the ICU as key editors, 104 papers were published, and 8 national multicenter trials that the physicians in the ICU were as key participants, and multiple team and individual honors were obtained. CONCLUSIONS: The construction of ICU hardware is the basis and prerequisite for the development of the discipline and the construction of ICU software is the soul and motivation of the discipline. The operation indexes of clinical medical treatment, teaching and scientific researches reflect the overall operation status of the discipline and the hospital.

Recombinant Immunotoxin Therapy of Glioblastoma: Smart Design, Key Findings, and Specific Challenges.

Recombinant immunotoxins (RITs) refer to a group of recombinant protein-based therapeutics, which consists of two components: an antibody variable fragment or a specific ligand that allows RITs to bind specifically to target cells and an engineered toxin fragment that kills the target cells upon internalization. To date, over 1,000 RITs have been generated and significant success has been achieved in the therapy of hematological malignancies. However, the immunogenicity and off-target toxicities of RITs remain as significant barriers for their application to solid tumor therapy. A group of RITs have also been generated for the treatment of glioblastoma multiforme, and some have demonstrated evidence of tumor response and an acceptable profile of toxicity and safety in early clinical trials. Different from other solid tumors, how to efficiently deliver the RITs to intracranial tumors is more critical and needs to be solved urgently. In this article, we first review the design and expression of RITs, then summarize the key findings in the preclinical and clinical development of RIT therapy of glioblastoma multiforme, and lastly discuss the specific issues that still remain to forward RIT therapy to clinical practice.

A bivalent recombinant immunotoxin with high potency against tumors with EGFR and EGFRvIII expression.

EGFR and EGFRvIII are overexpressed in various types of cancer, serving as optimal targets for cancer therapy. Capitalizing on the high specificity of humanized antibody 806 (mAb806) to the EGFR and EGFRvIII overexpressed in cancer, we designed and generated a bivalent recombinant immunotoxin (RIT, DT390-BiscFv806) by fusing the mAb806-derived bivalent single-chain variable fragment with a diphtheria toxin fragment, DT390. In vitro, DT390-BiscFv806 efficiently internalized into the cells and exhibited high cytotoxicity against the U87 glioblastoma cells and the EGFRvIII-transfected U87 (U87-EGFRvIII) cells with a half maximal inhibition concentration (IC50) of 1.47 nM and 2.26 × 10(-4) nM, respectively. Notably, DT390-BiscFv806 was 4 orders of magnitude more potent against the U87-EGFRvIII cells than against the parent U87 cells. The cytotoxicity against a group of 6 head and neck squamous cell carcinoma cell lines were further analyzed, showing an IC50 ranging from 0.24 nM to 156 nM, depending on the expression level of EGFR/EGFRvIII. In animals, the U87-EGFRvIII tumor xenografts grew extremely faster than the parental U87, and systemic administration of DT390-BiscFv806 significantly inhibited the growth of established U87-EGFRvIII and U87 tumor xenografts, showing a growth inhibition rate of 76.3% (59.82-96.2%) and 59.4% (31.5-76.0%), respectively. In pathology, the RIT-treated tumors exhibited a low mitotic activity and a large number of degenerative tumor cells, compared with the control tumors. The results indicate that DT390-BiscFv806 is promising for treatment of various types of cancer, especially for those with high EGFR expression or with EGFR and EGFRvIII co-expression.

An anti-PSMA bivalent immunotoxin exhibits specificity and efficacy for prostate cancer imaging and therapy.

Prostate specific membrane antigen (PSMA) is overexpressed on prostate tumor cells and the neovascular endothelia various solid tumors. A bivalent immunotoxin generated by fusing a fold-back single-chain diabody derived from the Fv fragments of an anti-PSMA monoclonal antibody with a truncated diphtheria toxin (DT) containing the activity and translocation domains [A-dmDT390-scfbDb(PSMA)] might be suitable for targeted therapy of tumors that overexpress PSMA. In this study, a PSMA-positive and a PSMA-negative prostate cancer cell lines were treated with immunotoxin A-dmDT390-scfbDb(PSMA) in order to study the tumor targeting specificity and therapeutic potential of the immunotoxin. The cellular uptake and selective toxicity of the immunotoxin were evident in monolayer cultures of PSMA-positive LNCaP prostate cancer cells but not in cultures of PSMA-negative PC-3 prostate cancer cells. Cellular accumulation of A-dmDT390-scfbDb(PSMA) increased with increasing incubation times and concentrations in LNCaP cells. The proportion of apoptotic LNCaP cells increased upon incubation with increasing doses of the fold-back immunotoxin. Optical imaging and MRI with the Alexa Fluor 680-labeled A-dmDT390-scfbDb(PSMA) confirmed the specific targeting and therapeutic efficacy of this immunotoxin towards PSMA-positive LNCaP solid tumor xenografts in athymic nude mice.

Recombinant Immunotoxin Therapy of Solid Tumors: Challenges and Strategies.

Immunotoxins are a group of protein-based therapeutics, basically comprising two functional moieties: one is the antibody or antibody Fv fragment that allows the immunotoxin to bind specifically to target cells; another is the plant or bacterial toxin that kills the cells upon internalization. Immunotoxins have several unique features which are superior to conventional chemotherapeutics, including high specificity, extraordinary potency, and no known drug resistance. Development of immunotoxins evolves with time and technology, but significant progress has been achieved in the past 20 years after introduction of recombinant DNA technique and generation of the first single-chain variable fragment of monoclonal antibodies. Since then, more than 1,000 recombinant immunotoxins have been generated against cancer. However, most success in immunotoxin therapy has been achieved against hematological malignancies, several issues persist to be significant barriers for effective therapy of human solid tumors. Further development of immunotoxins will largely focus on the improvement of penetration capability to solid tumor mass and elimination of immunogenicity occurred when given repeatedly to patients. Promising strategies may include construction of recombinant antibody fragments with higher binding affinity and stability, elimination of immunodominant T- and B-cell epitopes of toxins, modification of immunotoxins with macromolecules like poly(ethylene glycol) and liposomes, and generation of immunotoxins with humanized antibody fragments and human endogenous cytotoxic enzymes. In this paper, we briefly reviewed the evolution of immunotoxin development and then discussed the challenges of immunotoxin therapy for human solid tumors and the potential strategies we may seek to overcome the challenges.