Prognostic significance of metabolic enzyme pyruvate kinase M2 in breast cancer: A meta-analysis

Metabolic reprogramming and therapeutic resistance in primary and metastatic breast cancer

Metabolic alterations, a hallmark of cancer, enable tumor cells to adapt to their environment by modulating glucose, lipid, and amino acid metabolism, which fuels rapid growth and contributes to treatment resistance. In primary breast cancer, metabolic shifts such as the Warburg effect and enhanced lipid synthesis are closely linked to chemotherapy failure. Similarly, metastatic lesions often display distinct metabolic profiles that not only sustain tumor growth but also confer resistance to targeted therapies and immunotherapies. The review emphasizes two major aspects: the mechanisms driving metabolic resistance in both primary and metastatic breast cancer, and how the unique metabolic environments in metastatic sites further complicate treatment. By targeting distinct metabolic vulnerabilities at both the primary and metastatic stages, new strategies could improve the efficacy of existing therapies and provide better outcomes for breast cancer patients.

Role of tumor microenvironment in cancer progression and therapeutic strategy

Cancer is now considered a tumor microenvironment (TME) disease, although it was originally thought to be a cell and gene expression disorder. Over the past 20 years, significant advances have been made in understanding the complexity of the TME and its impact on responses to various anticancer therapies, including immunotherapies. Cancer immunotherapy can recognize and kill cancer cells by regulating the body's immune system. It has achieved good therapeutic effects in various solid tumors and hematological malignancies. Recently, blocking of programmed death-1 (PD-1), programmed death-1 ligand-1 (PD-L1), and programmed death Ligand-2 (PD-L2), the construction of antigen chimeric T cells (CAR-T) and tumor vaccines have become popular immunotherapies Tumorigenesis, progression, and metastasis are closely related to TME. Therefore, we review the characteristics of various cells and molecules in the TME, the interaction between PD-1 and TME, and promising cancer immunotherapy therapeutics.

Expression of substance P, neurokinin 1 receptor, Ki-67 and pyruvate kinase M2 in hormone receptor negative breast cancer and evaluation of impact on overall survival

BACKGROUND

Chronic inflammation is a hallmark of cancer, and it can be stimulated by many factors. Substance P (SP), through binding to neurokinin 1 receptor (NK1R), and pyruvate kinase M2 (PKM2) play critical roles in cancer development and progression via modulating the tumor microenvironment. This study aimed to investigate the prognostic significance of SP and PKM2 in combination with NK1R and Ki-67 in hormone receptor negative (HR-ve) breast cancer.

METHODS

Immunohistochemical expression levels of SP, NK1R, PKM2, and Ki-67 were measured in 144 paraffin-embedded breast cancer tissues (77 h -ve and 67 h + ve). SP, NK1R, and PKM2 were scored semiquantitatively, while Ki-67 was obtained by the percentage of total number of tumor cells with nuclear staining. The optimal cutoff value for SP, NK1R, PKM2, and Ki-67 were assessed by Cutoff Finder.

RESULTS

High SP expression in HR -ve breast cancer was associated with TNM stage (p = 0.020), pT stage (p = 0.035), pN stage (p = 0.002), axillary lymph node metastasis (p = 0.003), and NK1R expression level (p = 0.010). In HR + ve breast cancer, SP expression was associated with HER2 status (p = 0.001) and PKM2 expression level (p = 0.012). Regarding PKM2 expression level, it significantly associated with HER2 status (p = 0.001) and history of DCIS (p = 0.046) in HR-ve tumors, and with HER2 status (p < 0.001) and SP expression level (p = 0.012) in HR + ve tumors. Survival analysis revealed that high SP level negatively impacted overall survival in HR-ve tumors that had low NK1R level (p = 0.021). Moreover, high SP negatively impacted overall survival in HR-ve tumors that had low Ki-67 level (p = 0.005). High PKM2 negatively impacted overall survival in HR-ve cases with low SP (p = 0.047).

CONCLUSION

Combined expression levels of SP with NK1R or Ki-67, and PKM2 with SP could be used to predict survival in breast cancer patients with HR-ve tumors. Our findings suggest a role of SP/NK1R pathway and PKM2 in HR-ve breast cancer pathogenesis which should be further investigated to unveil the underlying molecular mechanisms.

Energy metabolism pathways in breast cancer progression: The reprogramming, crosstalk, and potential therapeutic targets

Breast cancer (BC) is a malignant tumor that seriously endangers health in women. BC, like other cancers, is accompanied by metabolic reprogramming. Among energy metabolism-related pathways, BC exhibits enhanced glycolysis, tricarboxylic acid (TCA) cycle, pentose phosphate pathway (PPP), glutamate metabolism, and fatty acid metabolism activities. These pathways facilitate the proliferation, growth and migration of BC cells. The progression of BC is closely related to the alterations in the activity or expression level of several metabolic enzymes, which are regulated by the intrinsic factors such as the key signaling and transcription factors. The metabolic reprogramming in the progression of BC is attributed to the aberrant expression of the signaling and transcription factors associated with the energy metabolism pathways. Understanding the metabolic mechanisms underlying the development of BC will provide a druggable potential for BC treatment and drug discovery.

Cellular reprogramming, chemoresistance, and dietary interventions in breast cancer

Breast cancer (BC) diagnosis has been associated with significant risk factors, including family history, late menopause, obesity, poor eating habits, and alcoholism. Despite the advances in the last decades regarding cancer treatment, some obstacles still hinder the effectiveness of therapy. For example, chemotherapy resistance is common in locally advanced or metastatic cancer, reducing treatment options and contributing to mortality. In this review, we provide an overview of BC metabolic changes, including the impact of restrictive diets associated with chemoresistance, the therapeutic potential of the diet on tumor progression, pathways related to metabolic health in oncology, and perspectives on the future in the area of oncological nutrition.

Targeting O-GlcNAcylation to overcome resistance to anti-cancer therapies

In cancer cells, metabolic reprogramming is associated with an alteration of the O-GlcNAcylation homeostasis. This post-translational modification (PTM) that attaches O-GlcNAc moiety to intracellular proteins is dynamically and finely regulated by the O-GlcNAc Transferase (OGT) and the O-GlcNAcase (OGA). It is now established that O-GlcNAcylation participates in many features of cancer cells including a high rate of cell growth, invasion, and metastasis but little is known about its impact on the response to therapies. The purpose of this review is to highlight the role of O-GlcNAc protein modification in cancer resistance to therapies. We summarize the current knowledge about the crosstalk between O-GlcNAcylation and molecular mechanisms underlying tumor sensitivity/resistance to targeted therapies, chemotherapies, immunotherapy, and radiotherapy. We also discuss potential benefits and strategies of targeting O-GlcNAcylation to overcome cancer resistance.

Advances of Tumorigenesis, Diagnosis at Early Stage, and Cellular Immunotherapy in Gastrointestinal Malignancies

Globally, in 2018, 4.8 million new patients have a diagnosis of gastrointestinal (GI) cancers, while 3.4 million people died of such disorders. GI malignancies are tightly relevant to 26% of the world-wide cancer incidence and occupies 35% of all cancer-associated deaths. In this article, we principally investigated molecular and cellular mechanisms of tumorigenesis in five major GI cancers occurring at esophagus, stomach, liver, pancreas, and colorectal region that illustrate high morbidity in Eastern and Western countries. Moreover, through this investigation, we not only emphasize importance of the tumor microenvironment in development and treatment of malignant tumors but also identify significance of M2PK, miRNAs, ctDNAs, circRNAs, and CTCs in early detection of GI cancers, as well as systematically evaluate contribution of personalized precision medicine including cellular immunotherapy, new antigen and vaccine therapy, and oncolytic virotherapy in treatment of GI cancers.

Prognostic Significance of O-GlcNAc and PKM2 in Hormone Receptor-Positive and HER2-Nonenriched Breast Cancer

Predictive metabolic biomarkers for the recurrent luminal breast cancer (BC) with hormone receptor (HR)-positive and human epidermal growth factor receptor type 2 (HER2)-negative are lacking. High levels of O-GlcNAcylation (O-GlcNAc) and pyruvate kinase isoenzyme M2 (PKM2) are associated with malignancy in BC; however, the association with the recurrence risk remains unclear. We first conduct survival analysis by using the METABRIC dataset to assess the correlation of PKM2 expression with BC clinical outcomes. Next, patients with HR⁺/HER2- luminal BC were recruited for PKM2/O-GlcNAc testing. Logistic regression and receiver operating characteristic curve analysis were performed to evaluate the 10-year DFS predicted outcome. Survival analysis of the METABRIC dataset revealed that high expression of PKM2 was significantly associated with worse overall survival in luminal BC. The high expression of O-GlcNAc or PKM2 was a significant independent marker for poor 10-year DFS using immunohistochemical analysis. The PKM2 or O-GlcNAc status was a significant predictor of DFS, with the combination of PKM2–O-GlcNAc status and T stage greatly enhancing the predictive outcome potential. In summary, O-GlcNAc, PKM2, and T stage serve as good prognostic discriminators in HR⁺/HER2⁻ luminal BC.

Cryptanshinone Inhibits the Glycolysis and Inhibits Cell Migration Through PKM2/β-Catenin Axis in Breast Cancer

Background

Breast cancer is one of the most prevalent gynecologic malignancies worldwide. Despite the high sensitivity in response to chemotherapy, drug resistance occurred frequently in clinical treatment. Cryptotanshinone (CTS) is a herbal medicine and has been identified as an anti-inflammatory and anti-oxidative drug.

Methods

In vitro assays, including the cell proliferation assay, colony formation assay, Western blot analysis, transwell migration/invasion assays, and cell scratch assay were used to explore the biological activities and working mechanism of CTS. Breast cancer cells were also transfected with PKM2 expressing vectors to define the molecular mechanisms involved in CTS-mediated anti-tumor activity.

Results

We found that CTS shows anti-proliferative effects and decreases the clonogenic ability of breast cancer cells. We also found that CTS inhibited the migration and invasion activity of MCF-7 and MDA-MB-231 cells by different analyzed methods. CTS also downregulated the levels of glycolysis-related proteins, such as PKM2, LDHA, and HK2. In addition, overexpression of PKM2 recovered CTS-mediated suppression of cell proliferation, colony formation, and cell mobility of breast cancer cells. We also found PKM2 was significantly overexpressed in tumor tissues and invasive ductal breast carcinoma compared to normal tissues and patients with high PKM2 expression had worse overall survival and metastasis-free survival outcomes.

Conclusion

CTS inhibited the proliferation, migration, and invasion of breast cancer cells. The involved mechanism may refer to the downregulation of the PKM2/β-catenin axis.

Targeting Glucose Metabolism to Overcome Resistance to Anticancer Chemotherapy in Breast Cancer

Breast cancer (BC) is the most prevalent cancer in women. BC is heterogeneous, with distinct phenotypical and morphological characteristics. These are based on their gene expression profiles, which divide BC into different subtypes, among which the triple-negative breast cancer (TNBC) subtype is the most aggressive one. The growing interest in tumor metabolism emphasizes the role of altered glucose metabolism in driving cancer progression, response to cancer treatment, and its distinct role in therapy resistance. Alterations in glucose metabolism are characterized by increased uptake of glucose, hyperactivated glycolysis, decreased oxidative phosphorylation (OXPHOS) component, and the accumulation of lactate. These deviations are attributed to the upregulation of key glycolytic enzymes and transporters of the glucose metabolic pathway. Key glycolytic enzymes such as hexokinase, lactate dehydrogenase, and enolase are upregulated, thereby conferring resistance towards drugs such as cisplatin, paclitaxel, tamoxifen, and doxorubicin. Besides, drug efflux and detoxification are two energy-dependent mechanisms contributing to resistance. The emergence of resistance to chemotherapy can occur at an early or later stage of the treatment, thus limiting the success and outcome of the therapy. Therefore, understanding the aberrant glucose metabolism in tumors and its link in conferring therapy resistance is essential. Using combinatory treatment with metabolic inhibitors, for example, 2-deoxy-D-glucose (2-DG) and metformin, showed promising results in countering therapy resistance. Newer drug designs such as drugs conjugated to sugars or peptides that utilize the enhanced expression of tumor cell glucose transporters offer selective and efficient drug delivery to cancer cells with less toxicity to healthy cells. Last but not least, naturally occurring compounds of plants defined as phytochemicals manifest a promising approach for the eradication of cancer cells via suppression of essential enzymes or other compartments associated with glycolysis. Their benefits for human health open new opportunities in therapeutic intervention, either alone or in combination with chemotherapeutic drugs. Importantly, phytochemicals as efficacious instruments of anticancer therapy can suppress events leading to chemoresistance of cancer cells. Here, we review the current knowledge of altered glucose metabolism in contributing to resistance to classical anticancer drugs in BC treatment and various ways to target the aberrant metabolism that will serve as a promising strategy for chemosensitizing tumors and overcoming resistance in BC.

Upregulated expression of pyruvate kinase M2 mRNA predicts poor prognosis in lung adenocarcinoma

Background

Pyruvate kinase M2 (PKM2) is critical regulator contributing to Warburg effect. However, the expression pattern and prognostic value of PKM2 remain unknown in lung adenocarcinoma (LUAD). The aim of this study is to clarify the prognostic value of PKM2 via intergrated bioinformatics analysis.

Methods

Firstly, mRNA expression levels of PKM2 in LUAD were systematically analyzed using the ONCOMINE and TCGA databases. Then, the association between PKM2 expression and clinical parameters was investigated by UALCAN. The Kaplan-Meier Plotter was used to assess the prognostic significance of PKM2. Finally, the relationship between PKM2 expression and its genetic and epigenetic changes was evaluated with MEXPRESS and MethHC database.

Results

Pooled analysis showed that PKM2 is frequently upregulated expression in LUAD. Subsequently, PKM2 expression was identified to be positively associated with tumor stage and lymph node metastasis and also strongly correlated with worse OS (P = 2.80e-14), PPS (P = 0.022), FP (P = 1.30e-6) and RFS (P = 3.41e-8). Importantly, our results demonstrated that over-expressed PKM2 is associated with PKM2 hypomethylation and copy number variations (CNVs).

Conclusion

This study confirms that over-expressed PKM2 in LUAD is associated with poor prognosis, suggesting that PKM2 might act as a promising prognostic biomarker and novel therapeutic target for LUAD.

FDG-PET reflects tumor viability on SUV in colorectal cancer liver metastasis

BACKGROUND

Liver resection is the most effective procedure for colorectal cancer liver metastasis (CRLM); however, early recurrence is an important problem that affects the postoperative prognoses of patients with CRLM. We previously suggested a therapeutic algorithm for CRLM using fluorodeoxyglucose-positron emission tomography (FDG-PET) and revealed the applicability of FDG-PET in predicting the prognosis after liver resection of CRLM. In this study, we assessed the correlation between FDG-PET and biological viability such as proliferation or metabolic activity.

METHODS

We retrospectively evaluated 61 patients who underwent hepatectomy for CRLM. We assessed hypoxia inducible factor-1α (HIF-1α), pyruvate kinase isozyme M2 (PKM2), glucose transporter 1 (GLUT1), and Ki-67 expression via immunohistochemistry and evaluated the correlation between standardized uptake value (SUV) and these factors.

RESULTS

High HIF-1α, PKM2, and GLUT1 expression were positively correlated with high SUV expression (P = 0.0444, 0.0296, and 0.0245, respectively). Ki-67 and SUV were also positively correlated (P = 0.00164). HIF-1α expression and PKM2 expression were significantly correlated (P = 0.0430), and PKM2 expression and GLUT1 expression were extremely significantly correlated (P < 0.0001).

CONCLUSION

SUV reflected tumor proliferation or metabolic factors in CRLM. FDG-PET could be a useful modality for assessing tumor viability and may provide useful information regarding the appropriate treatment strategy for CRLM.

AKT-dependent sugar addiction by benzyl isothiocyanate in breast cancer cells

The overall promise of breast cancer chemoprevention is exemplified by clinical success of selective estrogen receptor modulators and aromatase inhibitors. Despite clinical efficacy, these interventions have limitations, including rare but serious side effects and lack of activity against estrogen receptor-negative breast cancers. We have shown previously that dietary administration of benzyl isothiocyanate (BITC), which occurs naturally as a thioglucoside conjugate in edible cruciferous vegetables, inhibits development of estrogen receptor-negative breast cancer in mouse mammary tumor virus-neu (MMTV-neu) transgenic mice. This study demonstrates AKT-mediated sugar addiction in breast cancer chemoprevention by BITC. BITC-treated MMTV-neu mice exhibited increased 2-deoxy-2-(¹⁸ F)-fluoro-D-glucose (¹⁸ F-FDG) uptake in mammary tumors in vivo in comparison with mice fed basal diet. Cellular studies using MDA-MB-231 and SUM159 human breast cancer cell lines revealed BITC-mediated induction and punctate localization of glucose transporter GLUT-1, which was accompanied by an increase in intracellular pyruvate levels. BITC treatment resulted in increased S⁴⁷³ phosphorylation (activation) of AKT in cells in vitro as well as in mammary tumors of MMTV-neu mice in vivo. Increased glucose uptake, punctate pattern of GLUT-1 localization, and intracellular pyruvate levels resulting from BITC exposure were significantly attenuated in the presence of a pharmacological inhibitor of AKT (MK-2206). Inhibition of AKT augmented BITC-mediated inhibition of cell migration and colony formation. BITC-induced apoptotic cell death was also increased by pharmacological inhibition of AKT. These results indicate increased glucose uptake/metabolism by BITC treatment in breast cancer cells suggesting that breast cancer chemoprevention by BITC may be augmented by pharmacological inhibition of AKT.