A structural basis for lithium and substrate binding of an inositide phosphatase.

Inositol polyphosphate 1-phosphatase (INPP1) is a prototype member of metal-dependent/lithium-inhibited phosphomonoesterase protein family defined by a conserved three-dimensional core structure. Enzymes within this family function in distinct pathways including inositide signaling, gluconeogenesis, and sulfur assimilation. Using structural and biochemical studies, we report the effect of substrate and lithium on a network of metal binding sites within the catalytic center of INPP1. We find that lithium preferentially occupies a key site involved in metal-activation only when substrate or product is added. Mutation of a conserved residue that selectively coordinates the putative lithium-binding site results in a dramatic 100-fold reduction in the inhibitory constant as compared with wild-type. Furthermore, we report the INPP1/inositol 1,4-bisphosphate complex which illuminates key features of the enzyme active site. Our results provide insights into a structural basis for uncompetitive lithium inhibition and substrate recognition and define a sequence motif for metal binding within this family of regulatory phosphatases.

Camrelizumab in different PD-L1 expression cohorts of pre-treated advanced or metastatic non-small cell lung cancer: a phase II study.

BACKGROUND: This phase II study evaluated camrelizumab in different PD-L1 expression cohorts of patients with previously treated advanced/metastatic non-small cell lung cancer (NSCLC; NCT03085069, registered March 21, 2017). METHODS: Patients who progressed during/after chemotherapy were enrolled and divided into four cohorts based on PD-L1 tumor proportion score (TPS). Patients with EGFR/ALK alterations and PD-L1 TPS ≥ 50% were also eligible. All enrolled patients received camrelizumab at 200 mg IV Q2W. The primary endpoint was objective response rate. RESULTS: A total of 146 patients were enrolled. As of data cutoff on Aug 20, 2020, the median follow-up was 29.5 months (95% CI 27.4-30.8). Objective response rate was 17.8% (95% CI 12.0-25.0) and improved with the increasing PD-L1 TPS (TPS < 1%, 12.2% [95% CI 5.7-21.8]; ≥ 1-< 25%, 19.4% [95% CI 7.5-37.5]; ≥ 25-< 50%, 36.4% [95% CI 10.9-69.2]; ≥ 50%, 23.3% [95% CI 9.9-42.3]). No response was observed in the five patients harboring EGFR mutations. Median progression-free survival was 3.2 months (95% CI 2.0-3.4), and patients with positive PD-L1 TPS had longer progression-free survival. Median overall survival was 14.8 months (95% CI 10.2-18.7). Treatment-related adverse events (TRAEs) of any grade occurred in 87.7% of patients, and 21.2% had grade ≥ 3 TRAEs. CONCLUSION: Camrelizumab showed improved efficacy compared with historical data of the second-line chemotherapy in pre-treated advanced/metastatic NSCLC. Patients with positive PD-L1 expression derived greater benefit from camrelizumab. Camrelizumab has a manageable safety profile.

Efficacy and safety of recombinant human lymphotoxin-α derivative with cisplatin and fluorouracil in patients with metastatic esophageal squamous cell carcinoma: A randomized, multicenter, open-label, controlled, phase 2b trial.

BACKGROUND: Recombinant human lymphotoxin-α derivative (rhLTα-Da) is a lymphotoxin-α derivative that is missing 27 N-terminal amino acid residues. Previous studies indicated a benefit from the addition of rhLTα-Da to cisplatin-based treatment in patients with metastatic esophageal squamous cell carcinoma. The current study was conducted to evaluate the efficacy and safety of rhLTα-Da plus cisplatin and fluorouracil (PF) in patients with mESCC. METHODS: Patients from 15 centers in China were randomly assigned (1:1:1) to 3 arms (arm A, PF plus 10 µg/m2 daily rhLTα-Da; arm B, PF plus 20 µg/m2 daily rhLTα-Da; arm C, PF alone). The primary endpoints included progression-free survival (PFS) and the confirmed overall response rate (ORR). An exploratory analysis was performed to evaluate the role of serum tumor necrosis factor receptor II (TNFR II) in predicting the efficacy of rhLTα-Da. RESULTS: Between September 2010 and May 2013, 150 patients were enrolled. No significant differences in either PFS or ORR were observed between the 3 arms. However, in a small subset of patients who had low serum TNFR II levels, the median PFS was significantly longer for those in arm B than for these in other 2 arms (7.2 months [95% confidence interval, 5.1-8.6 months] for arm B vs 3.5 months [95% confidence interval, 1.7-5.5 months] for arm A [P = .022] and 4.0 months [95% confidence interval, 3.2-6.3 months] for arm C [P = .027]). The addition of rhLTα-Da significantly increased the incidence of chills (P < .001). CONCLUSIONS: rhLTα-Da combined with the PF regimen failed to improve PFS and ORR in patients with mESCC, except in a small subset that had low serum TNFR II concentrations. Cancer 2017;123:3986-94. © 2017 American Cancer Society.

Insights into the involvement of noncoding RNAs in 5-fluorouracil drug resistance.

5-Fluorouracil is a classic chemotherapeutic drug that is widely used to treat various cancers. However, patients often exhibit primary or acquired drug resistance during treatment with 5-fluorouracil chemotherapy. 5-Fluorouracil resistance is a multifactorial event that involves abnormal enzyme metabolism, transport deregulation, cell cycle disorders, apoptosis resistance, and mismatch repair deficiency. Despite advancements in bioresearch technologies in the past several decades, the molecular mechanisms of 5-fluorouracil resistance have not been completely clarified. Recently, microarray analyses have shown that noncoding RNAs (i.e. microRNAs and long noncoding RNAs) play a vital role in 5-fluorouracil resistance in multiple cancer cell lines. These noncoding RNAs can function as oncogenes or tumor suppressors, contributing to 5-fluorouracil drug resistance. In this review, we discuss the effects of microRNAs on 5-fluorouracil sensitivity via targeting of metabolic enzymes, the cell cycle, apoptosis, autophagy, the epithelial-mesenchymal transition, and cancer stem cells. In particular, we focus on summarizing current knowledge on the molecular mechanisms through which long noncoding RNAs mediate 5-fluorouracil drug resistance. Moreover, we describe the specific microRNAs that may function as markers for prediction of chemotherapeutic response to 5-fluorouracil. This review will help to improve the current understanding of how to reverse 5-fluorouracil resistance and may facilitate the establishment of new strategies for alleviating drug resistance in the future.

Resveratrol Treatment Inhibits Proliferation of and Induces Apoptosis in Human Colon Cancer Cells.

BACKGROUND: Resveratrol, a natural isolate from plant sources, has a long and important history in traditional Chinese medicine. In the present study we investigated the effect of resveratrol on human colon cancer cell lines. MATERIAL/METHODS: We used the Cell Counting kit-8 (CCK-8) for determination of colon cancer cell viability. Apoptosis induction was analyzed using the DeadEnd™ Colorimetric TUNEL System (Promega, Madison, WI, USA). The siRNA Transfection Reagent kit (Santa Cruz Biotechnology, Inc.) was used for the administration of COX-2 silencer RNA (siRNA) into the colon cancer cells. Primer Express® software for Real-Time PCR ver. 3.0 (Applied Biosystems, Foster City, CA, USA) was used to prepare the primers for RT-PCR. RESULTS: The results revealed that exposure of colon cancer cells to resveratrol inhibited cell viability. Resveratrol exhibited a significant inhibitory effect on cell viability at 30 µM concentration after 48 h of exposure. We observed that 30-µM doses of resveratrol for 72 h led to 18, 29, and 34% reduction in the viability of HCA-17, SW480, and HT29 cells, respectively. It also significantly induced apoptosis in both of the tested carcinoma cell lines. The population of apoptotic cells in HCA-17 and SW480 cell lines after 48 h of resveratrol treatment was 59.8±4 and 67.2±4%, respectively, compared to 2.3±1% in the control cells. The colon cancer cells exposed to resveratrol showed significantly lower cyclooxygenase-2 and prostaglandin receptor expression. Treatment of colon cancer cells with the inhibitor of cyclooxygenase-2, indomethacin, and administration of silencer RNA for cyclooxygenase-2 also produced similar results. CONCLUSIONS: These findings suggest that resveratrol treatment can be a promising strategy for the treatment of colon cancer.

Lichenoid drug eruption caused by imatinib mesylate in a Chinese patient with gastrointestinal stromal tumor.

Imatinib mesylate, the first agent approved for the treatment of unresectable or metastatic gastrointestinal stromal tumor, is a tyrosine kinase inhibitor targeting (KIT) and the platelet-derived growth factor receptor-α and -ß. However, imatinib administration can be accompanied by various adverse events. Here we report a case of Lichenoid drug eruption (LDE) that appeared 24 weeks after commencement of imatinib in a 73-year-old man with gastrointestinal stromal tumor (GIST). The skin lesions were distributed over his face, trunk and limbs, which improved only after discontinuation of imatinib therapy. To the best of our knowledge, this is the first report of imatinib-induced LDE in the Chinese population.

Simultaneous MV-kV imaging for intrafractional motion management during volumetric-modulated arc therapy delivery.

The purpose of this study was to evaluate the accuracy and clinical feasibility of a motion monitoring method employing simultaneously acquired MV and kV images during volumetric-modulated arc therapy (VMAT). Short-arc digital tomosynthesis (SA-DTS) is used to improve the quality of the MV images that are then combined with orthogonally acquired kV images to assess 3D motion. An anthropomorphic phantom with implanted gold seeds was used to assess accuracy of the method under static, typical prostatic, and respiratory motion scenarios. Automatic registra-tion of kV images and single MV frames or MV SA-DTS reconstructed with arc lengths from 2° to 7° with the appropriate reference fiducial template images was performed using special purpose-built software. Clinical feasibility was evaluated by retrospectively analyzing images acquired over four or five sessions for each of three patients undergoing hypofractionated prostate radiotherapy. The standard deviation of the registration error in phantom using MV SA-DTS was similar to single MV images for the static and prostate motion scenarios (σ = 0.25 mm). Under respiratory motion conditions, the standard deviation of the registration error increased to 0.7mm and 1.7 mm for single MV and MV SA-DTS, respectively. Registration failures were observed with the respiratory scenario only and were due to motion-induced fiducial blurring. For the three patients studied, the mean and standard deviation of the difference between automatic registration using 4° MV SA-DTS and manual registration using single MV images results was 0.07±0.52mm. The MV SA-DTS results in patients were, on average, superior to single-frame MV by nearly 1 mm - significantly more than what was observed in phantom. The best MV SA-DTS results were observed with arc lengths of 3° to 4°. Registration failures in patients using MV SA-DTS were primarily due to blockage of the gold seeds by the MLC. The failure rate varied from 2% to 16%. Combined MV SA-DTS and kV imaging is feasible for intratreatment motion monitoring during VMAT of anatomic sites where limited motion is expected, and improves registration accuracy compared to single MV/kV frames. To create a clinically robust technique, further improvements to ensure visualization of fiducials at the desired control points without degradation of the treatment plan are needed.

Erratum: Amarogentin secoiridoid inhibits in vivo cancer cell growth in xenograft mice model and induces apoptosis in human gastric cancer cells (SNU-16) through G2/M cell cycle arrest and PI3K/Akt signalling pathway.

In the version of this article initially published, in Volume 21, issue 3, the first affiliation (affiliation number 1) was incorrectly stated as "Department of Pathology, Faculty of Medicine, Adnan Menderes University, Aydin, Turkey". The correct affiliation is "Department of Oncology, Shaoxing People's Hospital ,Shaoxing Hospital of Zhejiang University, Shaoxing 312000,China'. This error appeared only in the PubMed database and not in the print form of the Journal.

Amarogentin secoiridoid inhibits in vivo cancer cell growth in xenograft mice model and induces apoptosis in human gastric cancer cells (SNU-16) through G2/M cell cycle arrest and PI3K/Akt signalling pathway.

PURPOSE: To investigate the in vitro and in vivo antitumor effects of amarogentin in SNU-16 human gastric cancer cells as well as in nude mice xenograft model. The effects of this compound on cell apoptosis, cell cycle phase distribution and PI3K/Akt and m-TOR signalling pathways were also studied in detail. METHODS: MTT assay was used to study the effect of amarogentin on SNU-16 cell viability while clonogenic assay indicated the effect of the compound on colony formation tendency of these cells. Phase contrast microscopy revealed the effect on cellular morphology while flow cytometry was engaged to study the effects on cell apoptosis and cell cycle arrest. SNU-16 cancer cells were subcutaneously inoculated into nude mice to investigate the in vivo antitumor effects of amarogentin. RESULTS: Amarogentin induced potent, dose-dependent as well as time-dependent cytotoxic effects on the growth of SNU-16 human gastric cancer cells. Amarogentin also inhibited the colony forming capability of these tumor cells and its treatment led to morphological alterations in these cells in which the cells became withered and rounded, detached from one another and adopted irregular shapes while floating freely in the culture medium. In comparison to untreated control cells, the amarogentin treated cells with 10, 50 and 75 µM exhibited 32.5, 45.2 and 57.1 % apoptotic cells, respectively. Amarogentin induced potent and dose-dependent G2/M cell cycle arrest in these cells and led to downregulation of m-TOR, p-PI3K, PI3K, p-Akt and Akt and upregulation of cyclin D1 and cyclin E protein expressions. The tumor tissues obtained from the amarogentin-treated mice were much smaller than the tumor tissues derived from the control group. CONCLUSION: Amarogentin exerts potent in vitro and in vivo antitumor effects in SNU-16 cell model as well as in nude mice xenograft model. These antitumor effects were found to be mediated through apoptosis induction, G2/M cell cycle arrest and downregulation of PI3K/Akt/m-TOR signalling pathways.

The α-subunit regulates stability of the metal ion at the ligand-associated metal ion-binding site in ß3 integrins.

The aspartate in the prototypical integrin-binding motif Arg-Gly-Asp binds the integrin ßA domain of the ß-subunit through a divalent cation at the metal ion-dependent adhesion site (MIDAS). An auxiliary metal ion at a ligand-associated metal ion-binding site (LIMBS) stabilizes the metal ion at MIDAS. LIMBS contacts distinct residues in the α-subunits of the two ß3 integrins αIIbß3 and αVß3, but a potential role of this interaction on stability of the metal ion at LIMBS in ß3 integrins has not been explored. Equilibrium molecular dynamics simulations of fully hydrated ß3 integrin ectodomains revealed strikingly different conformations of LIMBS in unliganded αIIbß3 versus αVß3, the result of stronger interactions of LIMBS with αV, which reduce stability of the LIMBS metal ion in αVß3. Replacing the αIIb-LIMBS interface residue Phe(191) in αIIb (equivalent to Trp(179) in αV) with Trp strengthened this interface and destabilized the metal ion at LIMBS in αIIbß3; a Trp(179) to Phe mutation in αV produced the opposite but weaker effect. Consistently, an F191/W substitution in cellular αIIbß3 and a W179/F substitution in αVß3 reduced and increased, respectively, the apparent affinity of Mn(2+) to the integrin. These findings offer an explanation for the variable occupancy of the metal ion at LIMBS in αVß3 structures in the absence of ligand and provide new insights into the mechanisms of integrin regulation.

Atomic basis for the species-specific inhibition of αV integrins by monoclonal antibody 17E6 is revealed by the crystal structure of αVß3 ectodomain-17E6 Fab complex.

The function-blocking, non-RGD-containing, and primate-specific mouse monoclonal antibody 17E6 binds the αV subfamily of integrins. 17E6 is currently in phase II clinical trials for treating cancer. To elucidate the structural basis of recognition and the molecular mechanism of inhibition, we crystallized αVß3 ectodomain in complex with the Fab fragment of 17E6. Protein crystals grew in presence of the activating cation Mn(2+). The integrin in the complex and in solution assumed the genuflected conformation. 17E6 Fab bound exclusively to the Propeller domain of the αV subunit. At the core of αV-Fab interface were interactions involving Propeller residues Lys-203 and Gln-145, with the latter accounting for primate specificity. The Propeller residue Asp-150, which normally coordinates Arg of the ligand Arg-Gly-Asp motif, formed contacts with Arg-54 of the Fab that were expected to reduce soluble FN10 binding to cellular αVß3 complexed with 17E6. This was confirmed in direct binding studies, suggesting that 17E6 is an allosteric inhibitor of αV integrins.

Phase II Study of Recombinant Antitumor and Antivirus Protein Injection Compared With Placebo in Metastatic Colorectal Cancer After Failure of Standard Treatment.

LESSONS LEARNED: Novaferon showed moderate efficacy and was well-tolerated in patients with metastatic colorectal cancer (mCRC), especially with the 20 µg injected 3 times a week strategy.Although Novaferon did not provide a survival benefit for mCRC patients who have failed standard treatment, it may play a role in improvement of immune function. BACKGROUND: To observe the efficacy, safety, and optimal dosage of recombinant antitumor and antivirus protein (Novaferon) in treating patients with metastatic colorectal cancer (mCRC) who failed at least two prior palliative regimens. METHODS: We enrolled 108 patients from May 2011 to December 2012. According to different treatment modalities and therapeutic dosages, the participants were randomly divided into four cohorts at a 2:2:2:1 ratio: (a) 20 µg Novaferon (Genova Biotech, Beijing, People's Republic of China, http://www.genovabiotech.net) injected twice per week, (b) 20 µg Novaferon injected 3 times per week, (c) 40 µg Novaferon injected 3 times per week, or (d) saline injected 3 times per week. The primary endpoint was overall survival. RESULTS: There was no significant difference in overall survival among the four cohorts. The 20-µg dose of Novaferon injected 3 times per week had the highest disease control rate (44.0%) at 6 weeks but without significant differences when compared with placebo (p = .159). Major adverse events with Novaferon were influenza-like symptoms, bone marrow suppression, liver dysfunction, and gastrointestinal discomfort. The level of natural killer cells increased and regulatory T cells decreased significantly after treatment with Novaferon, whereas levels in the placebo group remained the same. CONCLUSION: Novaferon showed moderate efficacy and was well tolerated in patients with mCRC, especially with the 20-µg dose injected 3 times per week. Furthermore, Novaferon might improve immune function of these patients.

MiR-1271 Inhibits Cell Proliferation, Invasion and EMT in Gastric Cancer by Targeting FOXQ1.

BACKGROUND/AIMS: FOXQ1 overexpression has been reported to enhance tumor growth and invasion. However, the biological function of FOXQ1 and the mechanism underlying its upregulation in gastric cancer (GC) remain unknown. METHODS: QPCR was used to detect the expression of miR-1271 and FOXQ1 in specimens from GC patients. FOXQ1-siRNA, and miR- 1271 mimics and inhibitor were transfected into human MGC-803 and SGC-7901 cells. The transwell assay was used to examine the cell invasive ability. The regulation mechanism was confirmed by luciferase reporter assay. Markers of epithelial-mesenchymal transition (EMT) were detected by western blot analysis. RESULTS: MiR-1271 was downregulated in both GC tissues and GC cell lines. The expression of miR-1271 was inversely correlated with tumor size (P = 0.017), tumor stage (P = 0.035), lymph node metastasis (P = 0.018), and TNM stage (P = 0.025). Ectopic expression of miR-1271 dramatically suppressed GC cell proliferation, invasion, and EMT. Furthermore, FOXQ1 was identified as a direct target of miR-1271. Knockdown of FOXQ1 inhibited GC cell malignant behavior, whereas FOXQ1 overexpression partially restored the suppression effects of miR-1271. Additionally, miR-1271 expression was negatively correlated with FOXQ1 in GC tissues. CONCLUSIONS: MiR-1271 inhibits cell proliferation, invasion, and EMT in GC by directly suppressing FOXQ1 expression.

miR-320 enhances the sensitivity of human colon cancer cells to chemoradiotherapy in vitro by targeting FOXM1.

miR-320 expression level is found to be down-regulated in human colon cancer. To date, however, its underlying mechanisms in the chemo-resistance remain largely unknown. In this study, we demonstrated that ectopic expression of miR-320 led to inhibit HCT-116 cell proliferation, invasion and hypersensitivity to 5-Fu and Oxaliplatin. Also, knockdown of miR-320 reversed these effects in HT-29 cells. Furthermore, we identified an oncogene, FOXM1, as a direct target of miR-320. In addition, miR-320 could inactive the activity of Wnt/ß-catenin pathway. Finally, we found that miR-320 and FOXM1 protein had a negative correlation in colon cancer tissues and adjacent normal tissues. These findings implied that miR-320-FOXM1 axis may overcome chemo-resistance of colon cancer cells and provide a new therapeutic target for the treatment of colon cancer.

Interference with the ß-catenin gene in gastric cancer induces changes to the miRNA expression profile.

Aberrant activation of the Wnt/ß-catenin signaling pathway plays a major role in carcinogenesis and the progression of many malignant tumors, especially gastric cancer (GC). Some research has suggested that expression of the ß-catenin protein is associated with clinicopathologic factors and affects the biological behaviors of GC cells. However, the mechanism of these effects is not yet clear. Studies show that the Wnt/ß-catenin pathway regulates some miRNAs. We hypothesize that oncogenic activation of ß-catenin signaling is involved in the formation of GC through regulating certain microRNAs (miRNAs). The results of the current study demonstrate that expression of the ß-catenin protein is associated with many clinicopathologic characteristics including the degree of differentiation, depth of tumor invasion, tumor site, and 5-year survival rate. We found that silencing the expression of ß-catenin with lentiviruses could delay cell proliferation, promote apoptosis, weaken the invasive power of GC cells, and increase the sensitivity of GC cells to 5-fluorouracil in vitro. Using miRNA microarrays to detect changes in the miRNA transcriptome following interference with ß-catenin in GC cells, we found that miR-1234-3p, miR-135b-5p, miR-210, and miR-4739 were commonly upregulated and that miR-20a-3p, miR-23b-5p, miR-335-3p, miR-423-5p, and miR-455-3p were commonly downregulated. These data provide a theoretical basis for the potential interaction between miRNA and the ß-catenin signaling pathway in GC.

Comparison of whole-body PET/PET-CT and conventional imaging procedures for distant metastasis staging in patients with breast cancer: a meta-analysis.

AIM: To compare the performance of whole-body PET/PET-CT with that of conventional imaging procedures for the overall assessment of distant metastasis in patients with breast cancer. MATERIALS AND METHODS: The authors performed a meta-analysis of all available studies of whole-body PET/PET-CT compared with conventional imaging procedures. They calculated sensitivities, specificities, positive likelihood ratios, negative likelihood ratios, and constructed summary receiver operating characteristic (ROC) curves using bivariate regression models for whole-body PET/PET-CT and conventional imaging procedures, respectively. RESULTS: Across six studies (609 patients), sensitivity, specificity, positive likelihood ratios, and negative likelihood ratios of whole-body PET/PET-CT were 0.99 (95% confidence interval [CI] = 0.88-1.00), 0.95 (95% CI = 0.89-0.98), 21.1 (95% CI = 8.2-55.5), and 0.02 (95% CI = 0.001-0.13), respectively, and of conventional imaging procedures they were 0.57 (95% CI = 0.37-0.74), 0.88 (95% CI = 0.78-0.94), 4.8 (95% CI = 2.8-8.2) and 0.49 (95% CI = 0.33-0.74), respectively. CONCLUSION: Compared with conventional imaging procedures, whole-body PET/PET-CT had excellent diagnostic performance for distant metastasis staging in patients with breast cancer.

Targeting miR-21 enhances the sensitivity of human colon cancer HT-29 cells to chemoradiotherapy in vitro.

5-Fluorouracil (5-FU) is a classic chemotherapeutic drug that has been widely used for colorectal cancer treatment, but colorectal cancer cells are often resistant to primary or acquired 5-FU therapy. Several studies have shown that miR-21 is significantly elevated in colorectal cancer. This suggests that this miRNA might play a role in this resistance. In this study, we investigated this possibility and the possible mechanism underlying this role. We showed that forced expression of miR-21 significantly inhibited apoptosis, enhanced cell proliferation, invasion, and colony formation ability, promoted G1/S cell cycle transition and increased the resistance of tumor cells to 5-FU and X radiation in HT-29 colon cancer cells. Furthermore, knockdown of miR-21 reversed these effects on HT-29 cells and increased the sensitivity of HT-29/5-FU to 5-FU chemotherapy. Finally, we showed that miR-21 targeted the human mutS homolog2 (hMSH2), and indirectly regulated the expression of thymidine phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD). These results demonstrate that miR-21 may play an important role in the 5-FU resistance of colon cancer cells.

Structure and mechanics of integrin-based cell adhesion.

Integrins are alpha/beta heterodimeric adhesion glycoprotein receptors that regulate a wide variety of dynamic cellular processes such as cell migration, phagocytosis, and growth and development. X-ray crystallography of the integrin ectodomain revealed its modular architecture and defined its metal-dependent interaction with extracellular ligands. This interaction is regulated from inside the cell (inside-out activation), through the short cytoplasmic alpha and beta integrin tails, which also mediate biochemical and mechanical signals transmitted to the cytoskeleton by the ligand-occupied integrins, effecting major changes in cell shape, behavior, and fate. Recent advances in the structural elucidation of integrins and integrin-binding cytoskeleton proteins are the subjects of this review.

Intra-Sac Injection of Thrombin During Endovascular Aneurysm Repair to Remedy Type II Endoleak and Promote Sac Shrinkage.

PURPOSE: To evaluate the safety and effectiveness of intra-sac thrombin injection to remedy type II endoleaks (T2ELs) during endovascular aneurysm repair (EVAR). MATERIALS AND METHODS: 224 cases abdominal aortic aneurysm (AAA) were treated with EVAR. For the 52 cases of intra-operative type II endoleaks and 8 cases of ruptured AAAs, after the grafts were deployed, thrombin was injected into the aneurysm sac through a preset catheter. The occurrence of endoleaks post-EVAR were followed up with by Computed Tomography (CT) angiogram. The diameter and the volume of the aneurysm sac were also measured. Endpoints included incidence of T2ELs, AAA sac shrinkage and re-intervention rate and all-cause mortality. RESULTS: The overall technical success rate was 100%. Fifty-two patients were followed up with for 9-56 (median 24) months. No serious complications were observed during follow-up. The incidence of endoleak was 5.8% (3/52) during follow-up. The maximum diameter of the aneurysm decreased from 61.1 ± 14.2 mm to 53.7 ± 10.6 mm, 47.9 ± 8.3 mm and 43.7 ± 7.2 mm (87.9%, 78.4% and 71.5% of pre-EVAR) at the 6-month, 1-year and 2-year follow-up, respectively (P < .05). The volume of the aneurysm sac shrank from 236.2 ± 136.2 cm3 to 202.6 ± 114.1 cm3, 155.6 ± 68.4 cm3 and 129.7 ± 52.4 cm3 (85.8%, 65.9%, and 54.9% of pre-EVAR) at the 6-month, 1-year and 2-year follow-up, respectively (P < .05). The rate of various endoleaks was 5.8% (3/52) and the re-intervention rate was 1.9% (1/52) in this research. CONCLUSIONS: Clinical outcomes show that intra-sac injection of thrombin during EVAR is safe and may be effective in remedying small amount and low-velocity endoleaks and promoting shrinkage of the aneurysm sac.

Stable coordination of the inhibitory Ca2+ ion at the metal ion-dependent adhesion site in integrin CD11b/CD18 by an antibody-derived ligand aspartate: implications for integrin regulation and structure-based drug design.

A central feature of integrin interaction with physiologic ligands is the monodentate binding of a ligand carboxylate to a Mg(2+) ion hexacoordinated at the metal ion-dependent adhesion site (MIDAS) in the integrin A domain. This interaction stabilizes the A domain in the high-affinity state, which is distinguished from the default low-affinity state by tertiary changes in the domain that culminate in cell adhesion. Small molecule ligand-mimetic integrin antagonists act as partial agonists, eliciting similar activating conformational changes in the A domain, which has contributed to paradoxical adhesion and increased patient mortality in large clinical trials. As with other ligand-mimetic integrin antagonists, the function-blocking mAb 107 binds MIDAS of integrin CD11b/CD18 A domain (CD11bA), but in contrast, it favors the inhibitory Ca(2+) ion over the Mg(2+) ion at MIDAS. We determined the crystal structures of the Fab fragment of mAb 107 complexed to the low- and high-affinity states of CD11bA. Favored binding of the Ca(2+) ion at MIDAS is caused by the unusual symmetric bidentate ligation of a Fab-derived ligand Asp to a heptacoordinated MIDAS Ca(2+) ion. Binding of the Fab fragment of mAb 107 to CD11bA did not trigger the activating tertiary changes in the domain or in the full-length integrin. These data show that the denticity of the ligand Asp/Glu can modify the divalent cation selectivity at MIDAS and hence integrin function. Stabilizing the Ca(2+) ion at MIDAS by bidentate ligation to a ligand Asp/Glu may provide one approach for designing pure integrin antagonists.