Hyperprogressive disease during PD-1 blockade in patients with advanced pancreatic cancer.

The occurrence of markedly accelerated tumor growth during immunotherapy is considered a new mode of progression called hyperprogressive disease (HPD) and its impact on pancreatic cancer (PC) patients receiving immunotherapy is unknown. In this study, we described and explored the incidence, prognosis and predictors of HPD in patients with advanced PC treated with programmed cell death-1 (PD-1) inhibitors. We retrospectively analyzed clinicopathological data from 104 patients with advanced pancreatic cancer who were treated with PD-1 inhibitors at our institution during 2015-2020 and identified 10 (9.6%) patients with HPD. Overall survival (OS) was significantly poorer in patients with HPD compared to patients with progressive disease (PD) (median OS: 5.6 vs. 3.6 months, p < .01). Clinicopathological factors associated with the occurrence of HPD included smoking, metastatic sites >2, liver metastasis, antibiotic therapy within 21 days before immunotherapy (Abx B21), hemoglobin (Hb) level <110 g/L, and PD-1 inhibitor treatment line >2. Subgroup analysis showed that high levels of CA19-9 at baseline were associated with the development of subsequent HPD (p = .024) and a worse prognosis (mOS:16.2 months vs. 6.1 months, p < .01). Our study demonstrated that HPD may occur in PC patients treated with PD-1 inhibitors and is associated with several clinicopathological characteristics and poor prognosis. The baseline tumor marker CA19-9 may be one of the early predictors of HPD development in PC patients receiving immunotherapy.

A composite indicator of derived neutrophil-lymphocyte ratio and lactate dehydrogenase correlates with outcomes in pancreatic carcinoma patients treated with PD-1 inhibitors.

Background: There are currently no established biomarkers that can predict whether advanced pancreatic carcinoma (PC) patients would benefit from immune checkpoint inhibitors (ICIs). Our study investigated whether the pretreatment composite biomarker of derived neutrophil-lymphocyte ratio (dNLR) and lactate dehydrogenase (LDH) can be used as a reliable prognostic factor for the survival of PC patients receiving PD-1 inhibitor therapy. Methods: Patients with advanced PC treated with PD-1 inhibitors at a single center from September 2015 to September 2020 were included. The high levels of dNLR (≥3) and LDH (≥250 U/L) were considered to be risk factors. Based on these two risk factors, patients in this study were categorized into two risk groups: the good dNLR-LDH group, without risk factors, and the intermediate/poor dNLR-LDH group, with one to two risk factors. Overall survival (OS) and progression-free survival (PFS) served as this study's primary and secondary endpoints. Cox regression models were used to identify independent prognostic factors for survival benefit. Results: There were 98 patients in our study. The good group included 61 (62.2%) patients and the intermediate/poor group included 37 (37.8%). The overall patients with PC who received immunotherapy had a median OS of 12.1 months, and the good dNLR-LDH group had a significantly longer OS compared with the intermediate/poor dNLR-LDH group (44.2 vs. 6.4 months; p < 0.010); median PFS was 3.7 and 2.5 months (p = 0.010). The number of metastatic sites >2 and immunotherapy as third-line or later was associated with worse PFS, and the line of immunotherapy and the dNLR-LDH indicator were independent prognostic factors for OS, according to multivariate analysis. Conclusion: The pretreatment composite biomarker of dNLR and LDH can be used as a prognostic biomarker in patients with advanced PC treated with PD-1 inhibitors.

Assessment of PD-L1 Expression on Circulating Tumor Cells for Predicting Clinical Outcomes in Patients with Cancer Receiving PD-1/PD-L1 Blockade Therapies.

BACKGROUND: Programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1) blockade immunotherapies have changed the landscape of cancer therapy. However, the main limitation of these therapies is the lack of definitively predictive biomarkers to predict treatment response. Whether PD-L1 expression on circulating tumor cells (CTCs) is associated with the clinical outcomes of immunotherapy remains to be extensively investigated. MATERIALS AND METHODS: One hundred fifty-five patients with different advanced cancers were enrolled in this study and treated with anti-PD-1/PD-L1 monoclonal antibodies. Using the Pep@MNPs method, CTCs were isolated and enumerated. The PD-L1 expression levels were analyzed by an immunofluorescence assay for semiquantitative assessment with four categories (negative, low, medium, and high). RESULTS: Prior to immunotherapy, 81.93% (127/155) of patients had PD-L1-positive CTCs, and 71.61% (111/155) had at least one PD-L1-high CTC. The group with PD-L1-positive CTCs had a higher disease control rate (DCR) (71.56%, 91/127), with a DCR of only 39.29% (11/28) for the remaining individuals (p = .001). The objective response rate and DCR in PD-L1-high patients were higher than those in the other patients (32.44% vs. 13.64%, p = .018 and 75.68% vs. 40.91%, p < .0001, respectively). The reduction in the counts and ratios of PD-L1-positive CTCs and PD-L1-high CTCs reflected a beneficial response to PD-1/PD-L1 inhibitors. Furthermore, patients with PD-L1-high CTCs had significantly longer progression-free survival (4.9 vs. 2.2 months, p < .0001) and overall survival (16.1 vs. 9.0 months, p = .0235) than those without PD-L1-high CTCs. CONCLUSION: The PD-L1 level on CTCs may serve as a clinically actionable biomarker for immunotherapy, and its dynamic changes could predict the therapeutic response. IMPLICATIONS FOR PRACTICE: This study was designed to investigate the role of programmed death-ligand 1 (PD-L1) expression on circulating tumor cells in predicting and monitoring response to programmed death-1 (PD-1)/PD-L1 blockade immunotherapies in patients with advanced cancer. The results of the study showed that PD-L1-high-expression circulating tumor cells (CTCs) were both a predictive biomarker and a prognostic factor in patients with advanced cancer treated with anti-PD-1/PD-L1 monoclonal antibodies. These observations suggest that PD-L1 level on CTCs is a potential clinical biomarker for immunotherapy.

PRSS contributes to cetuximab resistance in colorectal cancer.

Cetuximab improves the survival of patients with metastatic colorectal cancer. The main limitation is primary and secondary resistance, the underlying mechanism of which requires extensive investigation. We proved that PRSS expression levels are significantly negatively associated with the sensitivity of cancer cells to cetuximab. Detailed mechanistic analysis indicated that PRSS can cleave cetuximab, leading to resistance. Cetuximab or bevacizumab combined with SPINK1, a PRSS inhibitor, inhibited cell growth more efficiently than cetuximab or bevacizumab alone in xenograft models. PRSS levels in the serum of 156 patients with mCRC were analyzed, and poor efficacy of cetuximab therapy was observed in patients with aberrant PRSS expression. PRSS expression in monoclonal antibody (mAb)-treated patients with cancer from The Cancer Genome Atlas database was also evaluated to determine whether patients with higher PRSS expression have significantly reduced progression-free survival. Our work provides a strong scientific rationale for targeting PRSS in combination with cetuximab therapy.

Transcriptome Alterations in Liver Metastases of Colorectal Cancer After Acquired Resistance to Cetuximab.

BACKGROUND/AIM: Cetuximab in combination with chemotherapy is recommended as first-line therapy for metastatic colorectal cancer (mCRC) with wild-type RAS. However, drug resistance to cetuximab exists widely in mCRC and reduces the prognosis of patients. Although some genomic alterations have been demonstrated to drive acquired resistance to cetuximab, the overall compendium of inherent molecular mechanisms is still incomplete. MATERIALS AND METHODS: Four liver metastasis biopsies were collected from two mCRC patients who were treated with cetuximab in combination with 5-fluororacil plus leucovorin and oxaliplatin (FOLFOX) regimen. RESULTS: Transcriptomic analysis revealed global gene expression alterations between paired samples prior to treatment and after acquired resistance. Further bioinformatics analysis discovered differentially expressed protein-coding genes/lncRNAs/miRNAs, potential miRNA-mRNA regulatory networks and lncRNA-mRNA competing endogenous RNA network, which may be potential biomarkers or play roles during the process of acquired resistance to cetuximab. CONCLUSION: Our study contributes to deciphering the molecular mechanisms of acquired resistance to cetuximab.

A region-resolved mucosa proteome of the human stomach.

The human gastric mucosa is the most active layer of the stomach wall, involved in food digestion, metabolic processes and gastric carcinogenesis. Anatomically, the human stomach is divided into seven regions, but the protein basis for cellular specialization is not well understood. Here we present a global analysis of protein profiles of 82 apparently normal mucosa samples obtained from living individuals by endoscopic stomach biopsy. We identify 6,258 high-confidence proteins and estimate the ranges of protein expression in the seven stomach regions, presenting a region-resolved proteome reference map of the near normal, human stomach. Furthermore, we measure mucosa protein profiles of tumor and tumor nearby tissues (TNT) from 58 gastric cancer patients, enabling comparisons between tumor, TNT, and normal tissue. These datasets provide a rich resource for the gastrointestinal tract research community to investigate the molecular basis for region-specific functions in mucosa physiology and pathology including gastric cancer.

PIK3CA Mutations Contribute to Acquired Cetuximab Resistance in Patients with Metastatic Colorectal Cancer.

Purpose: Mutations in KRAS are considered to be the main drivers of acquired resistance to epidermal growth factor receptor (EGFR) blockade in patients with metastatic colorectal cancer (mCRC). However, the potential role of other genes downstream of the EGFR signaling pathway in conferring acquired resistance has not been extensively investigated.Experimental Design: Using circulating tumor DNA (ctDNA) from patients with mCRC and with acquired cetuximab resistance, we developed a targeted amplicon ultra-deep sequencing method to screen for low-abundance somatic mutations in a panel of genes that encode components of the EGFR signaling pathway. Mutations with significantly increased variant frequencies upon disease progression were selected by using quartile analysis. The functional consequences of the identified mutations were validated in cultured cells.Results: We analyzed 32 patients with acquired cetuximab resistance in a development cohort. Of them, seven (22%) carried five novel PIK3CA mutations, whereas eight (25%) carried previously reported KRAS mutations. Functional studies showed that novel PIK3CA mutations (all in exon 19; p.K944N, p.F930S, p.V955G, p.V955I, and p.K966E) promote cell viability in the presence of cetuximab. Only one novel PIK3CA mutation (p.K944N) was verified in one of the 27 patients with acquired resistance in a validation cohort, simultaneous KRAS and PIK3CA hotspot mutations were detected in two patients. Among the above 59 acquired resistance patients, those with PIK3CA or RAS mutations detected in ctDNA showed a pronounced decrease in progression-free survival than patients with no mutation.Conclusions: The PIK3CA mutations may potentially contribute to acquired cetuximab resistance in patients with mCRC. Clin Cancer Res; 23(16); 4602-16. ©2017 AACR.

MicroRNA Let-7b inhibits keratinocyte migration in cutaneous wound healing by targeting IGF2BP2.

Wound healing is a complex process which involves proliferation and migration of keratinocyte for closure of epidermal injuries. A member of microRNA family, let-7b, has been expressed in mammalian skin, but its exact role in keratinocyte migration is still not in knowledge. Here, we showed that let-7b regulates keratinocyte migration by targeting the insulin-like growth factor IGF2BP2. Overexpression of let-7b led to reduced HaCaT cell migration, while knockdown of let-7b resulted in enhanced migration. Furthermore, let-7b was decreased during wound healing in wild-type mice, which led us to construct the transgenic mice with overexpression of let-7b in skin. The re-epithelialization of epidermis of let-7b transgenic mice was reduced during wound healing. Using bioinformatics prediction software and a reporter gene assay, we found that IGF2BP2 was a target of let-7b, which contributes to keratinocyte migration. Introduction of an expression vector of IGF2BP2 also rescued let-7b-induced migration deficiency, which confirms that IGF2BP2 is an important target for let-7b regulation. Our findings suggest that let-7b significantly delayed the re-epithelialization possibly due to reduction of keratinocyte migration and restraints IGF2BP2 during skin wound healing.

DNA in serum extracellular vesicles is stable under different storage conditions.

BACKGROUND: Extracellular vesicles (EVs), including exosomes, microvesicles, and apoptotic bodies, can be secreted by most cell types and released in perhaps all biological fluids. EVs contain multiple proteins, specific lipids and several kinds of nucleic acids such as RNAs and DNAs. Studies have found that EVs contain double-stranded DNA and that genetic information has a certain degree of consistency with tumor DNA. Therefore, if genes that exist in exosomes are stable, we may be able to use EVs genetic testing as a new means to monitor gene mutation. METHODS: In this study, EVs were extracted from serum under various storage conditions (4 °C, room temperature and repeated freeze-thaw). We used western blotting to examine the stability of serum EVs. Then, we extracted DNA from EVs and tested the concentration changing under different conditions. We further assessed the stability of EVs DNA s using polymerase chain reaction (PCR) and Sanger sequencing. RESULTS: EVs is stable under the conditions of 4 °C (for 24 h, 72 h, 168 h), room temperature (for 6 h, 12 h, 24 h, 48 h) and repeated freeze-thaw (after one time, three times, five times). Also, serum DNA is mainly present in EVs, especially in exosomes, and that the content and function of DNA in EVs is stable whether in a changing environment or not. We showed that EVs DNA stayed stable for 1 week at 4 °C, 1 day at room temperature and after repeated freeze-thaw cycles (less than three times). However, DNA from serum EVs after 2 days at room temperature or after five repeated freeze-thaw cycles could be used for PCR and sequencing. CONCLUSIONS: Serum EVs and EVs DNA can remain stable under different environments, which is the premise that EVs could serve as a novel means for genetic tumor detection and potential biomarkers for cancer diagnostics and prognostics.

Lineage tracing reveals conversion of liver sinusoidal endothelial cells into hepatocytes.

Although liver sinusoidal endothelial cells (LSECs) have long been known to contribute to liver regeneration following injury, the exact role of these cells in liver regeneration remains poorly understood. In this work, we performed lineage tracing of LSECs in mice carrying Tie2-Cre or VE-cadherin-Cre constructs to facilitate fate-mapping of LSECs in liver regeneration. Some YFP-positive LSECs were observed to convert into hepatocytes following a two-thirds partial hepatectomy (PH). Furthermore, human umbilical vein endothelial cells (HUVECs) could be triggered to convert into cells that closely resembled hepatocytes when cultured with serum from mice that underwent an extended PH. These findings suggest that mature non-hepatocyte LSECs play an essential role in mammalian liver regeneration by converting to hepatocytes. The conversion of LSECs to hepatocyte-like (iHep) cells may provide a new approach to tissue engineering.