Carcinogenesis最新文献

Pancreatic ductal adenocarcinoma (PDAC) manifests diverse molecular subtypes, including the classical/progenitor and basal-like/squamous subtypes, with the latter known for its aggressiveness. We employed integrative transcriptome and metabolome analyses to identify potential genes contributing to the molecular subtype differentiation and its metabolic features. Our comprehensive analysis revealed that adrenoceptor alpha 2A (ADRA2A) was downregulated in the basal-like/squamous subtype, suggesting its potential role as a candidate suppressor of this subtype. Reduced ADRA2A expression was significantly associated with a high frequency of lymph node metastasis, higher pathological grade, advanced disease stage, and decreased survival among PDAC patients. In vitro experiments demonstrated that ADRA2A transgene expression and ADRA2A agonist inhibited PDAC cell invasion. Additionally, ADRA2A-high condition downregulated the basal-like/squamous gene expression signature, while upregulating the classical/progenitor gene expression signature in our PDAC patient cohort and PDAC cell lines. Metabolome analysis conducted on the PDAC cohort and cell lines revealed that elevated ADRA2A levels were associated with suppressed amino acid and carnitine/acylcarnitine metabolism, which are characteristic metabolic profiles of the classical/progenitor subtype. Collectively, our findings suggest that heightened ADRA2A expression induces transcriptome and metabolome characteristics indicative of classical/progenitor subtype with decreased disease aggressiveness in PDAC patients. These observations introduce ADRA2A as a candidate for diagnostic and therapeutic targeting in PDAC.

Precision oncology and tumor-agnostic drug development provide hope for enhancing outcomes among patients with pancreatic cancer. Tumor-agnostic therapies have emerged across various tumor types, driven by insights into shared biomarkers. In the case of pancreatic cancer, the prevalence of the KRAS gene mutation is noteworthy. However, there exist other actionable alterations, such as BRCA1/2 mutations and fusion genes (BRAF, FGFR2, RET, NTRK, NRG1, and ALK), which present potential targets for therapy. Notably, tumor-agnostic drugs have demonstrated efficacy in specific subsets of pancreatic cancer patients who harbor these genetic alterations. Despite the rarity of NTRK fusions in pancreatic cancer, larotrectinib and entrectinib have exhibited effectiveness in NTRK fusion-positive pancreatic cancers. Additionally, repotrectinib, a next-generation NTRK inhibitor, has shown promising activity in NTRK positive pancreatic cancer patients who have developed acquired resistance to previous NTRK inhibitors. Immune checkpoint inhibitors, such as pembrolizumab and dostarlimab, have proven to be effective in dMMR/MSI-H pancreatic cancers. Moreover, targeted therapies for BRAF V600, RET fusions, and HER2/neu overexpression have displayed promising results in specific subsets of pancreatic cancer patients. Emerging targets like NRG fusions, FGFR2 fusions, TP53 mutations, and KRAS G12C mutations present potential avenues for targeted therapy. Tumor-agnostic therapies have the potential to revolutionize pancreatic cancer treatment by focusing on specific genetic alterations. It is crucial to continue implementing comprehensive screening strategies that encompass the ability to detect all these tumor-agnostic biomarkers. This will be essential in identifying pancreatic cancer patients who may benefit from these therapies.

A noticeable characteristic of pancreatic ductal adenocarcinoma (PDAC) tumors is a dense tumor microenvironment with abundant and dense, desmoplastic stroma woven tightly with both cellular and matrix components. The high stromal density is associated with higher intratumor pressures which, until the last decade, was largely assumed to be tumor protective, confirmed by early studies demonstrating that altering the stroma was effective in genetically engineered models of PDAC. However, clinical trials using these approaches have been disappointing. There is increasing recognition that stroma heterogeneity is much greater than initially thought with an explosion of investigation into cancer-associated fibroblast (CAF) subpopulations led by experimental and single-cell transcriptomic studies. This review summarizes and attempts to harmonize the current transcriptomic data of CAF subpopulations. Understanding the heterogeneity of CAFs, the matrix, and other tumor microenvironment features will be critical to developing effective therapeutic approaches. Identifying model systems that best recapitulate the clinical behavior and treatment response of human PDAC will be important. Examining subpopulations as defined by clinical outcome will remain a critical step in defining clinically impactful CAF subtypes in larger clinical cohorts. The future of precision oncology in PDAC will depend on the integration of precision tumor epithelial and precision stroma approaches.

BRAF V600E, one of the most frequent mutations in the MAPK pathway, confers poor prognosis to colorectal cancers (CRCs), partly because of chemotherapeutic resistance. Oncogene-induced DNA damage responses (DDRs) that primarily activate p53 are important mechanistic barriers to the malignant transformation of cells; however, the mechanism underlying this impairment in cancer remains unknown. Here, we evaluated the responses of BRAFV600E-induced DDRs in two CRC cell lines, SW48 and LIM1215, both of which harbor wild-type TP53, KRAS, and BRAF. BRAFV600E transduction exhibited distinct phenotypes in these cells: SW48 cell proliferation markedly decreased, whereas that of LIM1215 increased. BRAFV600E expression induced the activation of oncogene-induced DDR signaling in SW48 cells, but not in LIM1215 cells, whereas chemotherapeutic agents similarly activated DDRs in both cell lines. Knockdown experiments revealed that these responses in SW48 cells were mediated by p53-p21 pathway activation. Comet assay (both alkaline and neutral) revealed that BRAFV600E increased single-strand breaks to the same extent in both cell lines; however, in the case of LIM1215 cells, it only facilitated double-strand breaks. Furthermore, the proliferation of LIM1215 cells, wherein no oncogene-induced DDRs occurred, was synergistically inhibited upon MDM2 inhibitor-mediated p53 activation combined with MEK inhibition. Taken together, these distinct DDR signaling responses highlight the novel characteristics of BRAFV600E-mutated CRC cells and define the therapeutic potential of p53 activation combined with MAPK inhibition against TP53 wild-type CRC harboring a BRAFV600E mutation.

New-onset diabetes (NOD) is a common condition among patients with pancreatic adenocarcinoma (PAAD) and is related to poor clinical outcomes. The potential impact of NOD on PAAD progression and the tumor microenvironment remains unclear. Here, we revealed that NOD in PAAD was associated with metabolic disorders. Utilizing three machine learning algorithms, a new-onset diabetes-related metabolism signature (NRMS) was established. Validated in three independent cohorts, patients with a high NRMS score exhibited worse prognosis. Moreover, an elevated NRMS score was associated with an immunosuppressive microenvironment and diminished response to immunotherapy. Further experiments demonstrated that ALDH3A1, a key feature in NRMS, was significantly up-regulated in tissues from PAAD patients with NOD and played a crucial role in tumor progression and immune suppression. Our findings highlight the potential of NRMS as a prognostic biomarker and an indicator of immunotherapy response for patients with PAAD.

Cancer cells exhibit heterogeneous metastatic potential, and high metastatic (HM) subclones can enhance the metastatic potential of low metastatic subclones by transmitting some factors. Exosomal miRNAs play a pivotal role in the crosstalk of heterogeneous metastatic subclones. This study discovered that miR-20a-3p was upregulated in colorectal adenocarcinoma (CRA), correlated with metastasis, and potentially served as a prognostic indicator for CRA. miR-20a-3p could promote the proliferation, migration, and invasion of CRA cells. Interestingly, HM CRA cells could promote malignant phenotypes of low metastatic CRA cells by transmitting exosomal miR-20a-3p. Mechanically, miR-20a-3p could inhibit neurofibromin 1(NF1), thereby activate the rat sarcoma viral oncogene (RAS)-mediated mitogen-activated protein kinases (MAPK) signaling pathway to drive the metastasis of CRA. In summary, our study provided evidence that colorectal cancer cells with HM potential drive metastasis by transmitting exosomal miR-20a-3p through modulating the NF1/MAPK pathway.

Nucleotide metabolism is the ultimate and most critical link in the self-replication process of tumors, including gastric cancer (GC). However, in clinical treatment, classic antitumor drugs such as 5-fluorouracil (5-FU) are mostly metabolic analogs of purines or pyrimidines, which lack specificity for tumor cells and therefore have significant side effects. It is unclear whether there are other drugs that can target nucleotide metabolism, except for nucleic acid analogs. Here, we found that a natural compound, dehydroabietylamine (DHAA), significantly reduced the viability and proliferation of GC cells and organoids. DHAA disrupts the purine and pyrimidine metabolism of GC cells, causing DNA damage and further inducing apoptosis. DHAA treatment decreased transcription and protein levels of key enzymes involved in the nucleotide metabolism pathway, with significant reductions in the expression of pyrimidine metabolism key enzymes CAD, DHODH, and purine metabolism key enzymes PAICS. We also found that DHAA directly binds to and reduces the expression of Forkhead box K2 (FOXK2), a common transcription factor for these metabolic enzymes. Ultimately, DHAA was shown to delay tumorigenesis in K19-Wnt1/C2mE transgenic mice model and reduce levels of CAD, DHODH, and PAICS in vivo. We demonstrate that DHAA exerts an anticancer effect on GC by targeting transcription factor FOXK2, reducing transcription of key genes for nucleotide metabolism and impairing nucleotide biosynthesis, thus DHAA is a promising candidate for GC therapy.

Merriam-Webster and Oxford define a xenobiotic as any substance foreign to living systems. Allura Red AC (a.k.a., E129; FD&C Red No. 40), a synthetic food dye extensively used in manufacturing ultra-processed foods and therefore highly prevalent in our food supply, falls under this category. The surge in synthetic food dye consumption during the 70s and 80s was followed by an epidemic of metabolic diseases and the emergence of early-onset colorectal cancer in the 1990s. This temporal association raises significant concerns, particularly given the widespread inclusion of synthetic food dyes in ultra-processed products, notably those marketed toward children. Given its interactions with key contributors to colorectal carcinogenesis such as inflammatory mediators, the microbiome, and DNA damage, there is growing interest in understanding Allura Red AC's potential impact on colon health as a putative carcinogen. This review discusses the history of Allura Red AC, current research on its effects on the colon and rectum, potential mechanisms underlying its impact on colon health, and provides future considerations. Indeed, although no governing agencies classify Allura Red AC as a carcinogen, its interaction with key guardians of carcinogenesis makes it suspect and worthy of further molecular investigation. The goal of this review is to inspire research into the impact of synthetic food dyes on colon health.