Thymidylate synthase prompts metastatic progression through the dTMP associated EMT process in pancreatic ductal adenocarcinoma

Thymidylate Synthase Overexpression Drives the Invasive Phenotype in Colon Cancer Cells

Thymidylate synthase (TYMS) is the crucial enzymatic precursor for DNA biosynthesis and, therefore, the critical target for numerous types of chemotherapy, including the most frequently applied agent in colon cancer treatment 5-fluorouracil (5-FU). TYMS also seems to be associated with cancer metastasis and acquiring mesenchymal character by tumor cells during epithelial–mesenchymal transition (EMT). Based on that knowledge, we decided to investigate the role of TYMS in the modulation of invasive ability in colon cancer cells, where its effect on cancer metastasis has not been studied in detail before. We employed colon cancer cells isolated from different stages of tumor development, cells undergoing EMT, and TYMS overexpressing cells. The elongation ratio, cell migration, invasion assay, and MMP-7 secretion were applied to analyze the cell behavior. Important epithelial and mesenchymal markers characteristic of EMT were examined at the protein level by Western blot assay. Overall, our study showed a correlation between TYMS level and invasion ability in colon cancer cells and, above all, a crucial role of TYMS in the EMT regulation. We postulate that chemotherapeutics that decrease or inhibit TYMS expression could increase the effectiveness of the therapy in patients with colon cancer, especially in the metastatic stage.

Distinct molecular phenotype and the potential prognostic value of immune prognostic index and tumor infiltrating lymphocytes in hepatoid adenocarcinoma of stomach

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Molecular classification of HAS should be mainly categorized into GS and CIN phenotypes with TP53 mutation.

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TILs and dNLR may help to screen appropriate candidates for ICIs treatment in HAS.

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dNLR demonstrated the potentiality as a reliable and economic predictor of prognosis in HAS.

Hepatoid adenocarcinoma of the stomach (HAS) is a particular subtype of Gastric cancer (GC) with distinct pathological characteristics and genetic profile, but most HAS patients were received identical regimens as common GC. To date, only a few studies has been conducted to investigate the molecular characteristics of HAS, which may prevent the rational application of new anticancer strategies. To further obtain the genetic features and potential predictive and prognostic biomarkers of HAS, our current study evaluated the clinical implications of spectrum molecular markers in 36 surgical resection specimens. None Epstein-Barr virus (EBV) positive and/or micro-satellite instable high (MSI-h) tumors occurred in our study implies that the molecular classification of HAS should be mainly categorized into genomic stable (GS) and chromosomal instability (CIN) phenotypes, and wild type P53 status predicts better prognosis. More importantly, although the prognosis and clinical characteristics were independent of programmed cell death-ligand 1 (PD-L1), the presence of tumor infiltrating lymphocytes (TILs) still suggested that a portion of the enrolled HAS patients are potentially appropriate candidates for immune checkpoint blockade therapy. Additionally, the immune prognostic index (IPI) and derived neutrophil to lymphocyte ratio (dNLR) demonstrated their potential as reliable and economic indicators for predicting prognosis of HAS. We hope this first systematic evaluation will help in deciphering the molecular characterization and potential individualized regimens for this particular subtype of GC.

Recent Advances in Our Knowledge of mCRC Tumor Biology and Genetics: A Focus on Targeted Therapy Development

Metastatic colorectal cancer (mCRC) remains a highly lethal malignancy although considerable progress has resulted from characterizing molecular alterations such as RAS mutation status and extent of microsatellite instability (MSI) to guide optimal use of available therapies. The availability of gene expression profiling, next generation sequencing technologies, proteomics analysis and other technologies provides high resolution information on individual tumors, including metastatic lesions to better define intra-tumor and inter-tumor heterogeneity. Recent literature applying this information to further customize personalized therapies is reviewed. Current biomarker-based stratification used to select optimal therapy that is personalized to the mutation profile of individual tumors is described. Recent literature using whole exome sequencing of metastatic lesions and primary CRC tumors and other advanced technologies to more fully elucidate the tumor biology specific to mCRC sub-types and to develop more precise therapies that improve outcomes is also reviewed.

Proteomics of Sentinel Lymph Nodes in Early Breast Cancer for Identification of Thymidylate Synthase as a Potential Biomarker to Flag Metastasis: A Preliminary Study

Introduction

Breast cancer is the second most common cancer in women across the world. Some of the patients who present in the early stage of disease are affected by metastasis to the axillary group of lymph nodes. The first among this group that is affected is called as sentinel lymph node, and its diagnosis is crucial for the staging of cancer thereby dictating the type of surgical therapy. Therefore, the sentinel lymph node status provides the most relevant information to the surgeon and patient prognosis. The expanded utilization of breast conservation surgery has declined the morbidity associated with mastectomy and axillary lymph node surgery. Recent interest is, therefore, centered on techniques that allow accurate assessment of the sentinel lymph node metastasis. A current procedure such as sentinel lymph node biopsy (SLNB) that is used to assess axillary lymph node metastasis is neither specific nor sensitive, and besides, it is time-consuming.

Objective

To compare the protein profiles between metastatic and non-metastatic lymph nodes to identify a biomarker that can flag lymph node metastasis.

Materials and Methods

Women with early breast cancer were screened using mammography imaging and recruited to the study. Surgical resection was done to remove the breast tissue, and sentinel lymph node was identified using fluorescein and methylene blue tracer. Lymph node was sliced, and one set was sent for histopathology, which was considered the gold standard to assess the metastatic status of the lymph node. One set of slices was taken for proteomic experiments. Proteins were labelled with fluorescent cyanine tags and were subjected to difference gel electrophoresis experiment. Differentially expressed spots that had at least a twofold relative ratio and consistent pattern across three sets of biological replicate experiments were marked. Gel spots were trypsin digested and identified on mass spectrometry machine. Validation study was done by Western blot experiment on the same set of samples.

Results

Thymidylate synthase has a twofold higher expression in the metastatic sentinel lymph nodes as compared to non-metastatic lymph nodes in early breast cancer patients.

Conclusion

Differential in gel expression proteomics is an ideal platform for the identification of potential protein biomarker candidates that can differentiate metastatic from non-metastatic lymph nodes in early breast cancer. The identification of thymidylate synthase offers a scope to develop an on-table diagnostic kit to assess the status of sentinel lymph nodes during mastectomy procedure to guide surgical management of axillary lymph nodes in early breast cancer.

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A non-proliferative role of pyrimidine metabolism in cancer

Background

Nucleotide metabolism is a critical pathway that generates purine and pyrimidine molecules for DNA replication, RNA synthesis, and cellular bioenergetics. Increased nucleotide metabolism supports uncontrolled growth of tumors and is a hallmark of cancer. Agents inhibiting synthesis and incorporation of nucleotides in DNA are widely used as chemotherapeutics to reduce tumor growth, cause DNA damage, and induce cell death. Thus, the research on nucleotide metabolism in cancer is primarily focused on its role in cell proliferation. However, in addition to proliferation, the role of purine molecules is established as ligands for purinergic signals. However, so far, the role of the pyrimidines has not been discussed beyond cell growth.

Scope of the review

In this review we present the key evidence from recent pivotal studies supporting the notion of a non-proliferative role for pyrimidine metabolism (PyM) in cancer, with a special focus on its effect on differentiation in cancers from different origins.

Major conclusion

In leukemic cells, the pyrimidine catabolism induces terminal differentiation toward monocytic lineage to check the aberrant cell proliferation, whereas in some solid tumors (e.g., triple negative breast cancer and hepatocellular carcinoma), catalytic degradation of pyrimidines maintains the mesenchymal-like state driven by epithelial-to-mesenchymal transition (EMT). This review further broadens this concept to understand the effect of PyM on metastasis and, ultimately, delivers a rationale to investigate the involvement of the pyrimidine molecules as oncometabolites. Overall, understanding the non-proliferative role of PyM in cancer will lead to improvement of the existing antimetabolites and to development of new therapeutic options.

Thymidylate synthase maintains the de-differentiated state of triple negative breast cancers

Cancer cells frequently boost nucleotide metabolism (NM) to support their increased proliferation, but the consequences of elevated NM on tumor de-differentiation are mostly unexplored. Here, we identified a role for thymidylate synthase (TS), a NM enzyme and established drug target, in cancer cell de-differentiation and investigated its clinical significance in breast cancer (BC). In vitro, TS knockdown increased the population of CD24⁺ differentiated cells, and attenuated migration and sphere-formation. RNA-seq profiling indicated repression of epithelial-to-mesenchymal transition (EMT) signature genes upon TS knockdown, and TS-deficient cells showed an increased ability to invade and metastasize in vivo, consistent with the occurrence of a partial EMT phenotype. Mechanistically, TS enzymatic activity was found essential for maintenance of the EMT/stem-like state by fueling a dihydropyrimidine dehydrogenase-dependent pyrimidine catabolism. In patient tissues, TS levels were found significantly higher in poorly differentiated and in triple negative BC, and strongly correlated with worse prognosis. The present study provides the rationale to study in-depth the role of NM at the crossroads of proliferation and differentiation, and depicts new avenues for the design of novel drug combinations for the treatment of BC.