Dynamic Metabolons Using Stimuli-Responsive Protein Cages.

Naturally evolved metabolons have the ability to assemble and disassemble in response to environmental stimuli, allowing for the rapid reorganization of chemical reactions in living cells to meet changing cellular needs. However, replicating such capability in synthetic metabolons remains a challenge due to our limited understanding of the mechanisms by which the assembly and disassembly of such naturally occurring multienzyme complexes are controlled. Here, we report the synthesis of chemical- and light-responsive protein cages for assembling synthetic metabolons, enabling the dynamic regulation of enzymatic reactions in living cells. Particularly, a chemically responsive domain was fused to a self-assembled protein cage subunit, generating engineered protein cages capable of displaying proteins containing cognate interaction domains on their surfaces in response to small molecular cues. Chemical-induced colocalization of sequential enzymes on protein cages enhances the specificity of the branched deoxyviolacein biosynthetic reactions by 2.6-fold. Further, by replacing the chemical-inducible domain with a light-inducible dimerization domain, we created an optogenetic protein cage capable of reversibly recruiting and releasing targeted proteins onto and from the exterior of the protein cages in tens of seconds by on-off of blue light. Tethering the optogenetic protein cages to membranes enables the formation of light-switchable, membrane-bound metabolons, which can repeatably recruit-release enzymes, leading to the manipulation of substrate utilization across membranes on demand. Our work demonstrates a powerful and versatile strategy for constructing dynamic metabolons in engineered living cells for efficient and controllable biocatalysis.

Prognostic significance of grade of malignancy based on histopathological differentiation and Ki-67 in pancreatic ductal adenocarcinoma.

OBJECTIVE: Tumor cell malignancy is indicated by histopathological differentiation and cell proliferation. Ki-67, an indicator of cellular proliferation, has been used for tumor grading and classification in breast cancer and neuroendocrine tumors. However, its prognostic significance in pancreatic ductal adenocarcinoma (PDAC) remains uncertain. METHODS: Patients who underwent radical pancreatectomy for PDAC were retrospectively enrolled, and relevant prognostic factors were examined. Grade of malignancy (GOM), a novel index based on histopathological differentiation and Ki-67, is proposed, and its clinical significance was evaluated. RESULTS: The optimal threshold for Ki-67 was determined to be 30%. Patients with a Ki-67 expression level > 30% rather than ≤ 30% had significantly shorter 5-year overall survival (OS) and recurrence-free survival (RFS). In multivariate analysis, both histopathological differentiation and Ki-67 were identified as independent prognostic factors for OS and RFS. The GOM was used to independently stratify OS and RFS into 3 tiers, regardless of TNM stage and other established prognostic factors. The tumor-node-metastasis-GOM stage was used to stratify survival into 5 distinct tiers, and surpassed the predictive performance of TNM stage for OS and RFS. CONCLUSIONS: Ki-67 is a valuable prognostic indicator for PDAC. Inclusion of the GOM in the TNM staging system may potentially enhance prognostic accuracy for PDAC.

A new staging system for postoperative prognostication in pancreatic ductal adenocarcinoma.

The current TNM staging system for pancreatic ductal adenocarcinoma (PDAC) has revised the definitions of T and N categories as well as stage groups. However, studies validating these modifications have yielded inconsistent results. The existing TNM staging system in prognostic prediction remains unsatisfactory. The prognosis of PDAC is closely associated with pathological and biological factors. Herein, we propose a new staging system incorporating distant metastasis, postoperative serum levels of CA19-9 and CEA, tumor size, lymph node metastasis, lymphovascular involvement, and perineural invasion to enhance the accuracy of prognosis assessment. The proposed staging system exhibited a strong correlation with both overall survival and recurrence-free survival, effectively stratifying survival into five distinct tiers. Additionally, it had favorable discrimination and calibration. Thus, the proposed staging system demonstrates superior prognostic performance compared to the TNM staging system, and can serve as a valuable complementary tool to address the limitations of TNM staging in prognostication.

Presence of tumor deposits is an indicator of poor prognosis in patients with pancreatic ductal adenocarcinoma.

Tumor deposits (TDs) are associated with poor prognosis in several malignancies and have been incorporated into the tumor-node-metastasis (TNM) staging system for colorectal cancer. This study aims to explore the significance of TDs in pancreatic ductal adenocarcinoma (PDAC). All patients who underwent pancreatectomy with a curative intent for PDAC were retrospectively enrolled. Patients were categorized into 2 groups according to the status of TDs: the positive group, in which TDs were present, and the negative group, in which TDs were absent. The prognostic significance of TDs was evaluated. In addition, a modified staging system was developed by incorporating TDs into the eighth edition of the TNM staging system. One hundred nine (17.8%) patients had TDs. Patients with TDs demonstrated significantly lower 5-year overall survival (OS) and recurrence-free survival (RFS) rates than those without TDs (OS: 9.1% vs. 21.5%, P=0.001; RFS: 6.1% vs. 16.7%, P<0.001). Even after matching, patients with TDs still had significantly worse OS and RFS than those without TDs. In the multivariate analysis, the presence of TDs was an independent prognostic factor in patients with PDAC. The survival of patients with TDs was similar to that of patients with N2 stage disease. The modified staging system had a greater Harrell's C-index than the TNM staging system, which indicates better performance in predicting survival. The presence of TDs was an independent prognostic factor for PDAC. Categorizing patients with TDs into N2 stage improved the accuracy of the TNM staging system in predicting prognosis.

Prognostic nutritional score based on pretreatment lymphocyte, platelet, and prealbumin predicts prognosis in patients with pancreatic cancer.

BACKGROUND AND OBJECTIVES: Pretreatment immunological indicators and nutritional factors are associated with survival of many malignancies. This study aims to develop a prognostic nutritional score based on a combination of pretreatment lymphocyte, platelet, and prealbumin (Co-LPPa) in patients with pancreatic cancer (PC) and to investigate the prognostic significance of this score. METHODS: Patients who underwent pancreatectomy with a curative intent for PC were retrospectively enrolled. A pretreatment prognostic score was established by immunological indicators and nutritional factors that were independently associated with survival. RESULTS: Pretreatment lymphocyte (<1.6 × 109 /L), platelet (<160 × 109 /L) and prealbumin (<0.23 g/L) were independently associated with poorer overall survival (OS) and recurrence-free survival (RFS), and were used to create the Co-LPPa score. The Co-LPPa scores were inversely related to OS and RFS, and were able to stratify survival into four groups. The survival differences among the four groups were all significant. Besides, the Co-LPPa scores could stratify survival independently of pathological prognostic factors. The Co-LPPa score was superior to prognostic nutritional index and carbohydrate antigen 19-9 in predicting OS and RFS. CONCLUSION: The Co-LPPa score could accurately predict the prognosis of PC patients who underwent curative resection. The score may be helpful for preoperative therapeutic strategies.

Focusing on the hypoxia-inducible factor pathway: role, regulation, and therapy for osteoarthritis.

Osteoarthritis (OA) is a common chronic disabling disease that affects hundreds of millions of people around the world. The most important pathological feature is the rupture and loss of articular cartilage, and the characteristics of avascular joint tissues lead to limited repair ability. Currently, there is no effective treatment to prevent cartilage degeneration. Studies on the mechanism of cartilage metabolism revealed that hypoxia-inducible factors (HIFs) are key regulatory genes that maintain the balance of cartilage catabolism-matrix anabolism and are considered to be the major OA regulator and promising OA treatment target. Although the exact mechanism of HIFs in OA needs to be further clarified, many drugs that directly or indirectly act on HIF signaling pathways have been confirmed by animal experiments and regarded as promising treatments for OA. Targeting HIFs will provide a promising strategy for the development of new OA drugs. This article reviews the regulation of HIFs on intra-articular cartilage homeostasis and its influence on the progression of osteoarthritis and summarizes the recent advances in OA therapies targeting the HIF system.

A Strategy of NIR Dual-Excitation Upconversion for Ratiometric Intracellular Detection.

Intracellular detection is highly desirable for biological research and clinical diagnosis, yet its quantitative analysis with noninvasivity, sensitivity, and accuracy remains challenging. Herein, a near-infrared (NIR) dual-excitation strategy is reported for ratiometric intracellular detection through the design of dye-sensitized upconversion probes and employment of a purpose-built NIR dual-laser confocal microscope. NIR dye IR808, a recognizer of intracellular analyte hypochlorite, is introduced as energy donor and Yb,Er-doped NaGdF4 upconversion nanoparticles are adopted as energy acceptor in the as-designed nanoprobes. The efficient analyte-dependent energy transfer and low background luminescence endow the nanoprobes with ultrahigh sensitivity. In addition, with the nonanalyte-dependent upconversion luminescence (UCL) excited by 980 nm as a self-calibrated signal, the interference from environmental fluctuation can be alleviated. Furthermore, the dual 808/980 nm excited ratiometric UCL is demonstrated for the quantification of the level of intracellular hypochlorite. Particularly, the intrinsic hypochlorite with only nanomolar concentration in live MCF-7 cells in the absence of exogenous stimuli is determined. Such an NIR dual-excitation ratiometric strategy based on dye-sensitized UCL probes can be easily extended to detect various intracellular analytes through tailoring the reactive NIR dyes, which provides a promising tool for probing biochemical processes in live cells and diagnosing diseases.

Graphene-Oxide-Modified Lanthanide Nanoprobes for Tumor-Targeted Visible/NIR-II Luminescence Imaging.

The synthesis of hydrophilic lanthanide-doped nanocrystals (Ln3+ -NCs) with molecular recognition ability for bioimaging currently remains a challenge. Herein, we present an effective strategy to circumvent this bottleneck by encapsulating Ln3+ -NCs in graphene oxide (NCs@GO). Monodisperse NCs@GO was prepared by optimizing GO size and core-shell structure of NaYF4 :Yb,Er@NaYF4 , thus combining the intense visible/near-infrared II (NIR-II) luminescence of NCs and the unique surface properties and biomedical functions of GO. Such nanostructures not only feature broad solvent dispersibility, efficient cell uptake, and excellent biocompatibility but also enable further modifications with various agents such as DNA, proteins, or nanoparticles without tedious procedures. Moreover, we demonstrate in proof-of-concept experiments that NCs@GO can realize simultaneous intracellular tracking and microRNA-21 visualization, as well as highly sensitive in vivo tumor-targeted NIR-II imaging at 1525 nm.

Direct Detection of Circulating Tumor Cells in Whole Blood Using Time-Resolved Luminescent Lanthanide Nanoprobes.

The detection of circulating tumor cells (CTCs) is crucial to early cancer diagnosis and the evaluation of cancer metastasis. However, it remains challenging due to the scarcity of CTCs in the blood. Herein, we report an ultrasensitive platform for the direct detection of CTCs using luminescent lanthanide nanoprobes. These were designed to recognize the epithelial cell adhesion molecules on cancer cells, allowing signal amplification through dissolution-enhanced time-resolved photoluminescence (TRPL) and the elimination of short-lived autofluorescence interference. This enabled the direct detection of blood breast-cancer cells with a limit of detection down to 1 cell/well of a 96-well plate. Moreover, blood CTCs (≥10 cells mL-1 ) can be detected in cancer patients with a detection rate of 93.9 % (14/15 patients). We envision that this ultrasensitive detection platform with excellent practicality may provide an effective strategy for early cancer diagnosis and prognosis evaluation.

Enhancing Antitumor Efficacy by Simultaneous ATP-Responsive Chemodrug Release and Cancer Cell Sensitization Based on a Smart Nanoagent.

The exploitation of smart nanoagents based drug delivery systems (DDSs) has proven to be a promising strategy for fighting cancers. Hitherto, such nanoagents still face challenges associated with their complicated synthesis, insufficient drug release in tumors, and low cancer cell chemosensitivity. Here, the engineering of an adenosine triphosphate (ATP)-activatable nanoagent is demonstrated based on self-assembled quantum dots-phenolic nanoclusters to circumvent such challenges. The smart nanoagent constructed through a one-step assembly not only has high drug loading and low cytotoxicity to normal cells, but also enables ATP-activated disassembly and controlled drug delivery in cancer cells. Particularly, the nanoagent can induce cell ATP depletion and increase cell chemosensitivity for significantly enhanced cancer chemotherapy. Systematic in vitro and in vivo studies further reveal the capabilities of the nanoagent for intracellular ATP imaging, high tumor accumulation, and eventual body clearance. As a result, the presented multifunctional smart nanoagent shows enhanced antitumor efficacy by simultaneous ATP-responsive chemodrug release and cancer cell sensitization. These findings offer new insights toward the design of smart nanoagents for improved cancer therapeutics.

Characteristics and prognosis of gastric cancer in patients aged ≥ 70 years.

AIM: To elucidate the prognostic value of age for gastric cancer and identify the optimal treatment for elderly gastric cancer patients. METHODS: We enrolled 920 patients with gastric cancer who underwent gastrectomy between January 2003 and December 2007 in our center. Patients were categorized into three groups: younger group (age < 50 years), middle-aged group (50-69 years), and elderly group (≥ 70 years). Clinicopathological features were compared among the three groups and potential prognostic factors were analyzed. The log-rank test was used to assess statistical differences between curves. Independent prognostic factors were identified by the Cox proportional hazards regression model. Stratified analysis was used to investigate the impact of age on survival at each stage. Cancer-specific survival was also compared among the three groups by excluding deaths due to reasons other than gastric cancer. We analyzed the potential prognostic factors for patients aged ≥ 70 years. Finally, the impact of extent of lymphadenectomy and postoperative chemotherapy on survival for each age group was evaluated. RESULTS: In the elderly group, there was a male predominance. At the same time, cancers of the upper third of the stomach, differentiated type, and less-invasive surgery were more common than in the younger or middle-aged groups. Elderly patients were more likely to have advanced tumor-node-metastasis (TNM) stage and larger tumors, but less likely to have distant metastasis. Although 5-year overall survival (OS) rate specific to gastric cancer was not significantly different among the three groups, elderly patients demonstrated a significantly lower 5-year OS rate than the younger and middle-aged patients (elderly vs middle-aged vs younger patients = 22.0% vs 36.6% vs 38.0%, respectively). In the TNM-stratified analysis, the differences in OS were only observed in patients with II and III tumors. In multivariate analysis, only surgical margin status, pT4, lymph node metastasis, M1 and sex were independent prognostic factors for elderly patients. The 5-year OS rate did not differ between elderly patients undergoing D1 and D2 lymph node resection, and these patients benefited little from chemotherapy. CONCLUSION: Age ≥ 70 years was an independent prognostic factor for gastric cancer after gastrectomy. D1 resection is appropriate and postoperative chemotherapy is possibly unnecessary for elderly patients with gastric cancer.

Impact of intraoperative blood loss on survival after curative resection for gastric cancer.

AIM: To elucidate the potential impact of intraoperative blood loss (IBL) on long-term survival of gastric cancer patients after curative surgery. METHODS: A total of 845 stage I-III gastric cancer patients who underwent curative gastrectomy between January 2003 and December 2007 in our center were enrolled in this study. Patients were divided into 3 groups according to the amount of IBL: group 1 (< 200 mL), group 2 (200-400 mL) and group 3 (> 400 mL). Clinicopathological features were compared among the three groups and potential prognostic factors were analyzed. The Log-rank test was used to assess statistical differences between the groups. Independent prognostic factors were identified by the Cox proportional hazards regression model. Stratified analysis was used to investigate the impact of IBL on survival in each stage. Cancer-specific survival was also compared among the three groups by excluding deaths due to reasons other than gastric cancer. Finally, we explored the possible factors associated with IBL and identified the independent risk factors for IBL ≥ 200 mL. RESULTS: Overall survival was significantly influenced by the amount of IBL. The 5-year overall survival rates were 51.2%, 39.4% and 23.4% for IBL less than 200 mL, 200 to 400 mL and more than 400 mL, respectively (< 200 mL vs 200-400 mL, P < 0.001; 200-400 mL vs > 400 mL, P = 0.003). Age, tumor size, Borrmann type, extranodal metastasis, tumour-node-metastasis (TNM) stage, chemotherapy, extent of lymphadenectomy, IBL and postoperative complications were found to be independent prognostic factors in multivariable analysis. Following stratified analysis, patients staged TNM I-II and those with IBL less than 200 mL tended to have better survival than those with IBL not less than 200 mL, while patients staged TNM III, whose IBL was less than 400 mL had better survival. Tumor location, tumor size, TNM stage, type of gastrectomy, combined organ resection, extent of lymphadenectomy and year of surgery were found to be factors associated with the amount of IBL, while tumor location, type of gastrectomy, combined organ resection and year of surgery were independently associated with IBL ≥ 200 mL. CONCLUSION: IBL is an independent prognostic factor for gastric cancer after curative resection. Reducing IBL can improve the long-term outcome of gastric cancer patients following curative gastrectomy.