Mitochondria-Related Transcriptome Characterization Associated with the Immune Microenvironment, Therapeutic Response and Survival Prediction in Pancreatic Cancer

(1) Background: Pancreatic cancer (PC) is one of the most lethal tumors. Mitochondrial dysfunction has been reported to be involved in cancer development; however, its role in PC has remained unclear. (2) Methods: The differentially expressed NMGs were selected between PC and normal pancreatic tissue. The NMG-related prognostic signature was established by LASSO regression. A nomogram was developed based on the 12-gene signature combined with other significant pathological features. An extensive analysis of the 12 critical NMGs was performed in multiple dimensions. The expression of some key genes was verified in our external cohort. (3) Results: Mitochondria-related transcriptome features was obviously altered in PC compared with normal pancreas tissue. The 12-NMG signature showed good performance in predicting prognosis in various cohorts. The high- and low-risk groups exhibited notable diversity in gene mutation characteristics, biological characteristics, chemotherapy response, and the tumor immune microenvironment. Critical gene expression was demonstrated in our cohort at the mRNA and protein levels and in organelle localization. (4) Conclusions: Our study analyzed the mitochondrial molecular characterization of PC, proving the crucial role of NMGs in PC development. The established NMG signature helps classify patient subtypes in terms of prognosis prediction, treatment response, immunological features, and biological function, providing a potential therapeutic strategy targeting mitochondrial transcriptome characterization.

Metabolic reprogramming of cancer-associated fibroblasts in pancreatic cancer contributes to the intratumor heterogeneity of PET-CT

Intratumor heterogeneity of positron emission tomography-computed tomography (PET-CT) is reflected by variable ¹⁸F-fluorodeoxyglucose (FDG) uptake. Increasing evidence has shown that neoplastic and non-neoplastic components can affect the total ¹⁸F-FDG uptake in tumors. Cancer-associated fibroblasts (CAFs) is considered as the main non-neoplastic components in tumor microenvironment (TME) of pancreatic cancer. Our study aims to explore the impact of metabolic changes in CAFs on heterogeneity of PET-CT. A total of 126 patients with pancreatic cancer underwent PET-CT and endoscopic ultrasound elastography (EUS-EG) before treatment. High maximum standardized uptake value (SUVmax) from the PET-CT was positively correlated with the EUS-derived strain ratio (SR) and indicated poor prognosis of patients. In addition, single-cell RNA analysis showed that CAV1 affected glycolytic activity and correlated with glycolytic enzyme expression in fibroblasts in pancreatic cancer. We also observed the negative correlation between CAV1 and glycolytic enzyme expression in the tumor stroma by using immunohistochemistry (IHC) assay in the SUVmax-high and SUVmax-low groups of pancreatic cancer patients. Additionally, CAFs with high glycolytic activity contributed to pancreatic cancer cell migration, and blocking CAF glycolysis reversed this process, suggesting that glycolytic CAFs promote malignant biological behavior in pancreatic cancer. In summary, our research demonstrated that the metabolic reprogramming of CAFs affects total ¹⁸F-FDG uptake in tumors. Thus, an increase in glycolytic CAFs with decreased CAV1 expression promotes tumor progression, and high SUVmax may be a marker for therapy targeting the neoplastic stroma. Further studies should clarify the underlying mechanisms.

Hyperglycemia predicts adverse prognosis in advanced pancreatic cancer patients

BACKGROUND

Diabetes mellitus is a prevalent comorbidity in pancreatic cancer. Previous studies have mainly concentrated on the association between diabetes and pancreatic cancer outcomes. However, research on the impact of hyperglycemia on the prognosis of patients with advanced pancreatic cancer is limited.

METHODS

Information on patients with advanced pancreatic cancer was collected from a prospectively maintained database, and the patients were divided into the hyperglycemia group (fasting blood glucose ≥7.0 mmol/L) and the normoglycemia group (fasting blood glucose < 7.0 mmol/L). Patients with preexisting diabetes were not included in these groups. The associations between hyperglycemia and clinical variables or prognosis were analyzed.

RESULTS

Among 697 patients with advanced pancreatic cancer and no prior history of diabetes, 25.3% were diagnosed with hyperglycemia. Patients older than 65 years had a higher risk of developing hyperglycemia (P = 0.044). Patients with hyperglycemia had a worse prognosis than those with normoglycemia (median survival, 7.5 vs. 8.8 months, P < 0.001). Hyperglycemia was associated with increased mortality (hazard ratio = 1.38; P = 0.003).

CONCLUSIONS

Hyperglycemia predicts worse overall survival in patients with advanced pancreatic cancer.

A new glance at autophagolysosomal-dependent or -independent function of transcriptional factor EB in human cancer

Autophagy-lysosome system plays a variety of roles in human cancers. In addition to being implicated in metabolism, it is also involved in tumor immunity, remodeling the tumor microenvironment, vascular proliferation, and promoting tumor progression and metastasis. Transcriptional factor EB (TFEB) is a major regulator of the autophagy-lysosomal system. With the in-depth studies on TFEB, researchers have found that it promotes various cancer phenotypes by regulating the autophagolysosomal system, and even in an autophagy-independent way. In this review, we summarize the recent findings about TFEB in various types of cancer (melanoma, pancreatic ductal adenocarcinoma, renal cell carcinoma, colorectal cancer, breast cancer, prostate cancer, ovarian cancer and lung cancer), and shed some light on the mechanisms by which it may serve as a potential target for cancer treatment.

Exosomes from TNF-α preconditioned human umbilical cord mesenchymal stromal cells inhibit the autophagy of acinar cells of severe acute pancreatitis via shuttling bioactive metabolites

Severe acute pancreatitis (SAP) is a common critical disease of the digestive system, with high mortality and a lack of effective prevention and treatment measures. Despite mesenchymal stromal cell transplantation having the potential to treat SAP, its clinical application prospect is limited, and the mechanism is unclear. Here, we reveal the therapeutic role of exosomes from TNF-α-preconditioned human umbilical cord mesenchymal stromal cells (HUCMSCs) in attenuating SAP and show that it is partly dependent on exosomal metabolites. Bioactive metabolomics analysis showed that 48 metabolites be significantly differentially expressed between the two groups (Exo-Ctrl group versus Exo-TNF-α group). Then, the further functional experiments indicated that 3,4-dihydroxyphenylglycol could be a key molecule mediating the therapeutic effect of TNF-α-preconditioned HUCMSCs. The animal experiments showed that 3,4-dihydroxyphenylglycol reduced inflammation and oxidative stress in the pancreatic tissue and inhibited acinar cell autophagy in a rat model of SAP. Mechanistically, we revealed that 3,4-dihydroxyphenylglycol activated the mTOR pathway to inhibit acinar cell autophagy and alleviate SAP. In summary, our study demonstrated that exosomes from TNF-α-preconditioned HUMSCs inhibit the autophagy of acinar cells of SAP by shuttling 3,4-dihydroxyphenylglycol and inhibiting the mTOR pathway. This study revealed the vital role and therapeutic potential of metabolite-derived exosomes in SAP, providing a new promising method to prevent and therapy SAP.

Comparison among different preclinical models derived from the same patient with a non-functional pancreatic neuroendocrine tumor

Pancreatic neuroendocrine tumors are the second most common tumors of the pancreas, and approximately half of patients are diagnosed with liver metastases. Currently, the improvement in the efficacy of relevant treatment methods is still limited. Therefore, there is an urgent need for in-depth research on the molecular biological mechanism of pancreatic neuroendocrine tumors. However, due to their relatively inert biology, preclinical models are extremely scarce. Here, the patient-derived organoid, and patient-derived xenograft were successfully constructed. These two models and the previously constructed cell line named SPNE1 all derived from the same patient with a grade 3 non-functional pancreatic neuroendocrine tumor, providing new tumor modeling platforms, and characterized using immunohistochemistry, whole-exome sequencing, and single-cell transcriptome sequencing. Combined with a tumor formation experiment in immunodeficient mice, we selected the model that most closely recapitulated the parental tumor. Overall, the patient-derived xenograft model most closely resembled human tumor tissue.

The stromal microenvironment endows pancreatic neuroendocrine tumors with spatially specific invasive and metastatic phenotypes

Cancer-associated fibroblasts (CAFs) play an important role in a variety of cancers. However, the role of tumor stroma in nonfunctional pancreatic neuroendocrine tumors (NF-PanNETs) is often neglected. Profiling the heterogeneity of CAFs can reveal the causes of malignant phenotypes in NF-PanNETs. Here, we found that patients with high stromal proportion had poor prognosis, especially for that with infiltrating stroma (stroma and tumor cells that presented an infiltrative growth pattern and no regular boundary). In addition, myofibroblastic CAFs (myCAFs), characterized by FAP+ and α-SMAhigh, were spatially closer to tumor cells and promoted the EMT and tumor growth. Intriguingly, only tumor cells which were spatially closer to myCAFs underwent EMT. We further elucidated that myCAFs stimulate TGF-β expression in nearby tumor cells. Then, TGF-β promoted the EMT in adjacent tumor cells and promoted the expression of myCAFs marker genes in tumor cells, resulting in distant metastasis. Our results indicate that myCAFs cause spatial heterogeneity of EMT, which accounts for liver metastasis of NF-PanNETs. The findings of this study might provide possible targets for the prevention of liver metastasis.

A novel immune checkpoint score system for prognostic evaluation in pancreatic adenocarcinoma

BACKGROUND

Pancreatic adenocarcinoma (PAAD) remains a lethal malignancy making the detection of novel prognostic biomarkers urgent. Limited studies have investigated the predictive capability of immune checkpoints in PAAD.

METHOD

Gene expression data and correlative clinical information of PAAD cohort were obtained from public databases, including TCGA, ICGC, GTEX and GEO databases. Risk factors were screened and used to establish a risk score model through LASSO and Cox regression analyses. The prognostic ability of the risk score model was demonstrated. The association between risk score with immune cells infiltration, immune checkpoint genes expression, immunogenic cell death, somatic mutations and signaling pathways enrichment were analysed. scRNA-seq data were collected to confirmed the immune checkpoints expression in PAAD samples. The prognosis prediction ability of OX40/TNFRSF4 was identified. The mRNA and protein expression of OX40 in our clinical specimens were examined by RT-PCR and IHC method and its prognosis ability was verified.

RESULTS

First of all, the difference of immune microenvironment between pancreatic cancer and adjacent tissues was shown. A risk score system based on three immune checkpoints (OX40, TNFSF14 and KIR3DL1) was established. The risk score model was an independent prognostic factor and performed well regarding overall survival (OS) predictions among PAAD patients. A nomogram was established to facilitate the risk model application in clinical prognosis. Immune cells including naive B cells, CD8⁺ T cells and Tregs were negatively correlated with the risk score. The risk score was associated with expression of immune checkpoint genes, immunogenic cell death related genes and somatic mutations. Glycolysis processes, IL-2-STAT5, IL-6-STAT3, and mTORC1 signaling pathways were enriched in the high-risk score group. Furthermore, scRNA-seq data confirmed that TNFRSF4, TNFSF14 and KIR3DL1 were expressed on immune cells in PAAD samples. We then identified OX40 as an independent prognosis-related gene, and a higher OX40 expression was associated with increased survival rate and immune environment change. In 84 PAAD clinical specimens collected from our center, we confirmed that higher OX40 mRNA expression levels were related to a good prognosis. The protein expression of OX40 on tumor-infiltrating immune cells (TIICs), endothelial cells and tumor cells was verified in PAAD tissues by immunohistochemistry (IHC) method.

CONCLUSIONS

Overall, our findings strongly suggested that the three-immune checkpoints score system might be useful in the prognosis and design of personalized treatments for PAAD patients. Finally, we identified OX40 as an independent potential biomarker for PAAD prognosis prediction.

Reconsidering the role of prophylactic pancreaticojejunostomy in pancreatic enucleation: balancing the benefits and risks

BACKGROUND

The incidence of postoperative pancreatic fistula (POPF) following enucleation is high, and prophylactic pancreaticojejunostomy (PPJ) is frequently performed. Minimally invasive enucleation (MEN) has been demonstrated to be safe and feasible, leaving most enucleation wounds exposed.

METHODS

The clinical data of 40 patients who underwent open enucleation with PPJ at our center between 2012 and 2021 were compared with those of 80 patients who underwent MEN.

RESULTS

The MEN group had better outcomes than the PPJ group in terms of intraoperative bleeding (50.0 versus 100.0 mL), postoperative semi-liquid diet recovery (2.0 versus 5.0 days), and postoperative length of stay (7.7 versus 12.5 days). While the MEN group had higher rates of complex enucleation (60.0% versus 40.0%), main pancreatic duct repair (32.5% versus 10.0%), discharge with drains (48.8% versus 25.0%), and grade B POPFs (47.5% versus 17.5%). Both surgical methods effectively preserved pancreatic function; however, two patients in the PPJ group experienced severe haemorrhaging and died. Additionally, during the follow-up period, gastrointestinal bleeding was found and discomfort in the surgical area was reported.

CONCLUSION

Pancreatic enucleation combined with PPJ should be avoided, and although a biochemical or grade B POPF may develop after MEN, it can be compensated for by preserving pancreatic function and ensuring a good long-term quality of life in the patients.

Laparoscopic pancreaticoduodenectomy with portal or superior mesenteric vein resection and reconstruction for pancreatic cancer: A single-center experience

BACKGROUND

Open pancreaticoduodenectomy (OPD) with portal or superior mesenteric vein resection and reconstruction has been applied in pancreatic cancer patients with tumor infiltration or adherence. However, it is controversial whether laparoscopic pancreaticoduodenectomy (LPD) with major vascular resection and reconstruction is feasible. This study aimed to evaluate the safety and feasibility of LPD with major vascular resection compared with OPD with major vascular resection.

METHODS

We reviewed data for all pancreatic cancer patients undergoing LPD or OPD with vascular resection at Department of Pancreatic Surgery, Fudan University Shanghai Cancer Center, between February 2018 and May 2022. We compared the preoperative, intraoperative, and postoperative clinicopathological data of the two groups to conduct a comprehensive evaluation of LPD with major vascular resection.

RESULTS

A total of 63 patients underwent pancreaticoduodenectomy (PD) with portal or superior mesenteric vein resection and reconstruction, including 25 LPDs and 38 OPDs. The LPD group had less intraoperative blood loss (200 vs. 400 mL, P < 0.001), lower proportion of intraoperative blood transfusion (16.0% vs. 39.5%, P = 0.047), longer operation time (390 vs. 334 min, P = 0.004) and shorter postoperative hospital stay (11 vs. 14 days, P = 0.005). There was no perioperative death in all patients. There was no significant difference in the incidence of total postoperative complications, grade B/C postoperative pancreatic fistula, delayed gastric emptying and abdominal infection between the two groups. No postpancreatectomy hemorrhage nor bile leakage occurred during perioperative period. There was no significant difference in R0 resection rate and number of lymph nodes harvested between the two groups. Patency of reconstructed vessels in the two groups were 96.0% and 92.1%, respectively (P = 0.927).

CONCLUSIONS

LPD with portal or superior mesenteric vein resection and reconstruction was safe, feasible and oncologically acceptable for selected patients with pancreatic cancer, and it can achieve similar or even better perioperative results compared to open approach.

NLRP4 renders pancreatic cancer resistant to olaparib through promotion of the DNA damage response and ROS-induced autophagy

Olaparib has been approved as a therapeutic option for metastatic pancreatic ductal adenocarcinoma patients with BRCA1/2 mutations. However, a significant majority of pancreatic cancer patients have inherent resistance or develop tolerance to olaparib. It is crucial to comprehend the molecular mechanism underlying olaparib resistance to facilitate the development of targeted therapies for pancreatic cancer. In this study, we conducted an analysis of the DepMap database to investigate gene expression variations associated with olaparib sensitivity. Our findings revealed that NLRP4 upregulation contributes to increased resistance to olaparib in pancreatic cancer cells, both in vitro and in vivo. RNA sequencing and Co-IP MS analysis revealed that NLRP4 is involved in the DNA damage response and autophagy pathway. Our findings confirmed that NLRP4 enhances the capacity for DNA repair and induces the production of significant levels of reactive oxygen species (ROS) and autophagy in response to treatment with olaparib. Specifically, NLRP4-generated mitochondrial ROS promote autophagy in pancreatic cancer cells upon exposure to olaparib. However, NLRP4-induced ROS do not affect DNA damage. The inhibition of mitochondrial ROS using MitoQ and autophagy using chloroquine (CQ) may render cells more susceptible to the effects of olaparib. Taken together, our findings highlight the significant roles played by NLRP4 in the processes of autophagy and DNA repair when pancreatic cancer cells are treated with olaparib, thereby suggesting the potential therapeutic utility of olaparib in pancreatic cancer patients with low NLRP4 expression.

Knockdown of TACC3 inhibits tumor cell proliferation and increases chemosensitivity in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant digestive tract tumor with limited clinical treatments. Transforming acidic coiled-coil-containing protein 3 (TACC3) is a component of the centrosome axis and a member of the TACC family, which affect mitosis and regulate chromosome stability and are involved in tumor development and progression. However, the role of TACC3 in PDAC remains elusive. In this study, by exploiting the TCGA database, we found that high TACC3 expression in PDAC is associated with poor prognosis. shRNA-mediated TACC3 knockdown caused S phase arrest of the cell cycle and inhibited proliferation in PDAC cell lines. Through RNA sequencing and protein co-immunoprecipitation combined with mass spectrometry, KIF11 was identified as a protein that interacts with TACC3. TACC3 stabilizes and regulates KIF11 protein expression levels in PDAC cells through physical interaction. Knockdown of TACC3 or KIF11 resulted in abnormal spindle formation during cell division both in vitro and in vivo. Pharmacological inhibition of TACC3 or KIF11 can suppress tumor cell proliferation and promote apoptosis. Our studies further demonstrated that high expression of TACC3 and KIF11 mediated the resistance of PDAC to gemcitabine, and deficiency of TACC3 or KIF11 increased the sensitivity of PDAC cells to chemotherapy. In conclusion, our study reveals the fundamental role of TACC3 expression in PDAC cell proliferation and chemoresistance, suggesting that TACC3 can be used as a molecular marker to evaluate the prognosis of PDAC.

[Minimally invasive enucleation for benign and low-grade malignant pancreatic tumors: an analysis of 60 cases]

Objective: To investigate the safety and feasibility of minimally invasive pancreatic tumor enucleation. Methods: The clinicopathological data of 60 patients with minimally invasive pancreatic tumor enucleation admitted to the Department of Pancreatic Surgery of Fudan University Cancer Center from November 2019 to August 2021 were retrospectively analyzed. There were 17 males and 43 females,with age of (50.0±13.2)years(range: 23 to 73 years). Tumors were located in the head of pancreas in 40 cases(66.7%),neck and tail of pancreas in 20 cases(33.3%). Patients were divided into robotic group(n=25) and laparoscopic group(n=35) according to surgical methods. The measurement data were compared by t-test or Mann-Whitney U test, and the categorical data were compared by χ² test or Fisher exact probability method. The influencing factors of postoperative pancreatic fistula were analyzed by univariate and multivariate Logistic regression. Results: All patients successfully completed tumor enucleation without conversion to laparotomy. The operation time was (183.5±67.3)minutes(range:90 to 410 minutes). Twelve patients(20.0%) underwent stent placement and pancreatic duct repair during operation. The removal time of abdominal drainage tube after operation was (24.7±22.9)days(range:2 to 113 days). The tumor diameter in the robotic group was larger than that in the laparoscopic group((3.5±0.9)cm vs. (2.9±0.7)cm,t=-2.825,P=0.006). The incidences of postoperative biochemical fistula and grade B pancreatic fistula were 20.0%,22.9% and 36.0%,51.4%,respectively(χ²=2.289,P=0.318). There were no grade C pancreatic fistula,lymphatic fistula,biliary fistula,delayed gastric emptying,secondary operation and perioperative death in both groups. Multivariate logistic regression analysis was performed on the occurrence of clinically related pancreatic fistula(above grade B). The results showed that the increase of body mass index(OR=1.285,95%CI:1.053 to 1.569,P=0.014),the larger diameter of the tumor(OR=3.703,95%CI:1.465 to 9.360,P=0.006) and intraoperative pancreatic duct repair(OR=7.889,95%CI:1.471 to 42.296,P=0.016) were independent risk factors,whereas robotic surgery(OR=0.168,95%CI:0.036 to 0.796,P=0.025) was a protective factor. No case of pancreatin dependent dyspepsia and new onset diabetes mellitus was observed. Conclusions: Minimally invasive tumor enucleation is feasible in the treatment of benign and low-grade pancreatic tumors. The incidence of pancreatic fistula is high in the short term after operation,but serious complications are rare. The robot assisted system can reduce the risk of postoperative pancreatic fistula and has more advantages in dealing with larger diameter tumors because of clearer surgical vision and more accurate operation.

Distinctive grade based on Ki67 index and immune microenvironment of metastatic pancreatic neuroendocrine tumors responding to capecitabine plus temozolomide

BACKGROUND

Ki67 index changes during the treatment of metastatic pancreatic neuroendocrine tumor (PanNET) treatment. The study aimed to detect alterations of grade based on Ki67 index and immune microenvironment in PanNET responding to capecitabine/temozolomide (CapTem).

METHOD

Retrospective data of patients with PanNET were collected. In control group, 35 patients underwent surgery immediately after biopsy. In CapTem group, 38 patients received CapTem after biopsy and responded well to treatment (defined as either stable disease or partial response), and subsequently underwent surgery. All patients have pathological Ki67 index at biopsy and after surgery. CD163 + CD68 + CD206 + M2 macrophages, CD68 + CD86 + CD80 + M1 macrophages, CD11b + CD33 + myeloid-derived suppressor cells, and CD4 + CD25 + regulatory T cells were stained using multiplex immunofluorescence.

RESULTS

In control group, the paired grade based on Ki67 index directly after surgery showed no upgrade or downgrade compared to biopsy. In patients who responded well to CapTem, the grade based on Ki67 index before and after CapTem was altered. Thirteen patients had upgraded Ki67 index and 11 patients had downgraded. The proportion of stable disease was higher in the upgraded group compared to downgraded group (p = 0.0155). And upgraded group had a significantly shorter mPFS than patients in the downgrade group (8.5 months vs. 20 months, HR 4.834, 95% CI 1.414 to 16.53, p = 0.012). M1 macrophages was significantly lower in the downgraded group than in the Ki67 upgraded group (p < 0.001).

CONCLUSION

Grade based on Ki67 index and immune environment change in PanNET patients responding well to CapTem. Patients with downgraded had longer mPFS compared to those with upgraded. It is necessary to reassess the Ki67 index after CapTem treatment, even in patients responding well to CapTem.

EGFR is a potential therapeutic target for highly glycosylated and aggressive pancreatic neuroendocrine neoplasms

pNENs are relative indolent tumors with heterogeneous clinical presentation at diagnosis. It is important to establish aggressive subgroups of pNENs and identify potential therapeutic targets. Patients with pNEN (322 cases) were included to examine the association between glycosylation biomarkers and clinical/pathological traits. The molecular and metabolic features stratified by glycosylation status were assessed by RNA-seq/whole exome sequencing and immunohistochemistry. A considerable proportion of patients had elevated glycosylation biomarkers (carbohydrate antigen [CA] 19-9, 11.9%; CA125, 7.5%; carcinoembryonic antigen [CEA], 12.8%). CA19-9 (hazard ratio [HR] = 2.26, P = .019), CA125 (HR = 3.79, P = .004) and CEA (HR = 3.16, P = .002) were each independent prognostic variables for overall survival. High glycosylation group, defined as pNENs with elevated level of circulating CA19-9, CA125 or CEA, accounted for 23.4% of all pNENs. High glycosylation (HR = 3.14, P = .001) was an independent prognostic variable for overall survival and correlated with G3 grade (P < .001), poor differentiation (P = .001), perineural invasion (P = .004) and distant metastasis (P < .001). Epidermal growth factor receptor (EGFR) was enriched in high glycosylation pNENs using RNA-seq. EGFR was expressed in 21.2% of pNENs using immunohistochemistry and associated with poor overall survival (P = .020). A clinical trial focusing on EGFR expressed pNENs was initiated (NCT05316480). Thus, pNEN with aberrant glycosylation correlates with a dismal outcome and suggests potential therapeutic target of EGFR.