Pancreatic cancer and adaptive metabolism in a nutrient-deficient environment

Down-Regulation of AKT Proteins Slows the Growth of Mutant-KRAS Pancreatic Tumors

Serine/threonine kinase AKT isoforms play a well-established role in cell metabolism and growth. Most pancreatic adenocarcinomas (PDACs) harbor activation mutations of KRAS, which activates the PI3K/AKT signaling pathway. However, AKT inhibitors are not effective in the treatment of pancreatic cancer. To better understand the role of AKT signaling in mutant-KRAS pancreatic tumors, this study utilized proteolysis-targeting chimeras (PROTACs) and CRISPR-Cas9-genome editing to investigate AKT proteins. The PROTAC down-regulation of AKT proteins markedly slowed the growth of three pancreatic tumor cell lines harboring mutant KRAS. In contrast, the inhibition of AKT kinase activity alone had very little effect on the growth of these cell lines. The concurrent genetic deletion of all AKT isoforms (AKT1, AKT2, and AKT3) in the KPC (KrasG12D; Trp53R172H; Pdx1-Cre) pancreatic cancer cell line also dramatically slowed its growth in vitro and when orthotopically implanted in syngeneic mice. Surprisingly, insulin-like growth factor-1 (IGF-1), but not epidermal growth factor (EGF), restored KPC cell growth in serum-deprived conditions, and the IGF-1 growth stimulation effect was AKT-dependent. The RNA-seq analysis of AKT1/2/3-deficient KPC cells suggested that reduced cholesterol synthesis may be responsible for the decreased response to IGF-1 stimulation. These results indicate that the presence of all three AKT isoforms supports pancreatic tumor cell growth, and the pharmacological degradation of AKT proteins may be more effective than AKT catalytic inhibitors for treating pancreatic cancer.

Down-regulation of AKT proteins slows the growth of mutant-KRAS pancreatic tumors

Serine/threonine kinase AKT isoforms play a well-established role in cell metabolism and growth. Most pancreatic adenocarcinoma (PDAC) harbors activation mutations of KRAS, which activates the PI3K/AKT signaling pathway. However, AKT inhibitors are not effective in the treatment of pancreatic cancer. To better understand the role of AKT signaling in mutant-KRAS pancreatic tumors, this study utilizes proteolysis-targeting chimeras (PROTACs) and CRISPR-Cas9-genome editing to investigate AKT proteins. PROTAC down-regulation of AKT proteins markedly slowed the growth of three pancreatic tumor cell lines harboring mutant KRAS. In contrast, inhibition of AKT kinase activity alone had very little effect on the growth of these cell lines. Concurrent genetic deletion of all AKT isoforms (AKT1, AKT2, and AKT3) in the KPC (KrasG12D; Trp53R172H; Pdx1-Cre) pancreatic cancer cell line also dramatically slowed its growth in vitro and when orthotopically implanted in syngeneic mice. Surprisingly, insulin-like growth factor-1 (IGF-1), but not epidermal growth factor (EGF), restored KPC cell growth in serum-deprived conditions and the IGF-1 growth stimulation effect was AKT dependent. RNA-seq analysis of AKT1/2/3-deficient KPC cells suggested that reduced cholesterol synthesis may be responsible for the decreased response to IGF-1 stimulation. These results indicate that the presence of all three AKT isoforms supports pancreatic tumor cell growth and pharmacological degradation of AKT proteins may be more effective than AKT catalytic inhibitors for treating pancreatic cancer.

Changes in intestinal bacteria and imbalances of metabolites induced in the intestines of pancreatic ductal adenocarcinoma patients in a Japanese population: a preliminary result

BACKGROUND

The relationship between pancreatic ductal adenocarcinoma (PDAC) and the intestinal environment is not fully understood. The purpose of this study was to elucidate the characteristics of the intestinal environment in PDAC.

METHODS

We performed a case-control study of 5 Japanese patients with unresectable PDAC located in the body or tail (PDAC-bt). The number of patients analyzed was limited for this preliminary study. We included 68 healthy subjects, herein control, of pre-printed study in the preliminary study. 16S rRNA amplicon sequencing and metabolomic analysis were performed using fecal samples from the subjects.

RESULTS

There was no difference in the Shannon index and Principal Coordinate Analysis between PDAC-bt and the control. However, a significant increase in oral-associated bacteria (Actinomyces, Streptococcus, Veillonella, Lactobacillus) was observed. A significant decrease of Anaerostipes was demonstrated in the feces of PDAC-bt compared with the control. The intestinal propionic acid and deoxycholic acid were significantly lower in PDAC-bt compared with the control.

CONCLUSIONS

We showed that the intestinal environment of PDAC-bt is characterized by an increase in oral-associated bacteria and an imbalance of metabolites but without changes in alpha and beta diversity of the gut microbiota profiles.Clinical Trial Registration: www.umin.ac.jp, UMIN 000041974, 000023675, 000023970.

Emerging current trends and research focus related to pancreatic cancer metabolism: A bibliometric and visualized analysis

Background

As a malignant digestive system tumor, pancreatic cancer has unique metabolic characteristics. In recent years, the study of pancreatic cancer metabolism is in full swing, which provides a new direction for the treatment of pancreatic cancer patients. However, there is no systematic report of pancreatic cancer metabolism. In this paper, bibliometrics and visualization methods were used to analyze the number of publications, countries/regions, authors, institutions, journals, co-cited references, and keywords of pancreatic cancer metabolism articles, to summarize the research trends and predict research hotspots.

Methods

We searched, screened and downloaded articles on pancreatic cancer metabolism through the Web of Science Core Collection (WoSCC). Using CiteSpace, VOSviewer and Bibliometrix Package to analyze publications, countries/regions, authors, institutions, journals, co-cited references, and keywords of pancreatic cancer metabolism to identify research trends and predict research hotspots.

Results

According to the inclusion and exclusion criteria, a total of 5,255 articles were retrieved during the period 1943-2022. The number of publications on pancreatic cancer metabolism is increasing year by year. The United States (n=1602, 30.49%), China (n=1074, 20.44%), and Italy (n=313, 5.96%) are the three countries with the largest number of publications and citations, and there is close cooperation between countries. LI J (n=55) is the most prolific author. FUDAN UNIV (n=348) is the most published institution. CANCERS (n=118), PLOS ONE (n=93), and CANCER RESEARCH (n=80) are the most popular journals in this field. "Nutriment-deficient environment", "cancer chemoprevention" and "targeting cancer stem cell" are the main areas of focus. "immunotherapy", "ferroptosis" and "targeted therapy" are hot keywords in recent years. Taking pancreatic cancer metabolism as an entry point to study the role of traditional Chinese medicine (TCM) mainly focuses on curcumin and resveratrol, lack of broader and deeper research on TCM.

Conclusions

The number of publications on pancreatic cancer metabolism has generally increased, and scholars have generally paid more attention to this field. "immunotherapy", "ferroptosis" and "targeted therapy" are the current research hotspots. The in-depth study of pancreatic cancer metabolism will provide new ideas for the treatment of pancreatic cancer.