PKM2-c-Myc-Survivin Cascade Regulates the Cell Proliferation, Migration, and Tamoxifen Resistance in Breast Cancer

Nanoliposomes as nonviral vectors in cancer gene therapy

Nonviral vectors, such as liposomes, offer potential for targeted gene delivery in cancer therapy. Liposomes, composed of phospholipid vesicles, have demonstrated efficacy as nanocarriers for genetic tools, addressing the limitations of off-targeting and degradation commonly associated with traditional gene therapy approaches. Due to their biocompatibility, stability, and tunable physicochemical properties, they offer potential in overcoming the challenges associated with gene therapy, such as low transfection efficiency and poor stability in biological fluids. Despite these advancements, there remains a gap in understanding the optimal utilization of nanoliposomes for enhanced gene delivery in cancer treatment. This review delves into the present state of nanoliposomes as carriers for genetic tools in cancer therapy, sheds light on their potential to safeguard genetic payloads and facilitate cell internalization alongside the evolution of smart nanocarriers for targeted delivery. The challenges linked to their biocompatibility and the factors that restrict their effectiveness in gene delivery are also discussed along with exploring the potential of nanoliposomes in cancer gene therapy strategies by analyzing recent advancements and offering future directions.

PKM2 promotes myoblast growth and inosine monophosphate-specific deposition in Jingyuan chicken

Inosine monophosphate (IMP) is widely regarded as an important indicator for evaluating the flavour of poultry meat. However, little is known about the molecular mechanisms affecting the specific deposition of IMP. In this study, we functionally verified PKM2 (Pyruvate kinase M2), a candidate gene related to IMP synthesis, in order to reveal the important role of PKM2 in meat flavour and muscle development of Jingyuan chickens. The results showed that the IMP content in breast muscle of Jingyuan chickens was negatively correlated with PKM2 mRNA expression (r = -0.1710), while the IMP content in leg muscle was significantly positively correlated with PKM2 mRNA expression (r = 0.7350) (P < 0.05). During myogenesis, PKM2 promoted the proliferation rate of myoblasts and the expression of proliferation marker genes, inhibited the apoptosis rate and the expression of apoptosis marker genes, and decreased the expression of differentiation marker genes. Up-regulation of PKM2 enhanced the expression of key genes in the purine metabolic pathway and the de novo synthesis pathway of IMP, and suppressed the expression of key genes in the salvage pathway. ELISA assays showed that PKM2 decreased IMP and hypoxanthine (HX) contents, while adenosine triphosphate (ATP) and uric acid (UA) contents were clearly elevated. In summary, these studies revealed that PKM2 regulates myogenesis and specific deposition of IMP, which can be used to improve the quality of Jingyuan chicken meat.

Phytochemicals Target Multiple Metabolic Pathways in Cancer

Cancer metabolic reprogramming is a complex process that provides malignant cells with selective advantages to grow and propagate in the hostile environment created by the immune surveillance of the human organism. This process underpins cancer proliferation, invasion, antioxidant defense, and resistance to anticancer immunity and therapeutics. Perhaps not surprisingly, metabolic rewiring is considered to be one of the "Hallmarks of cancer". Notably, this process often comprises various complementary and overlapping pathways. Today, it is well known that highly selective inhibition of only one of the pathways in a tumor cell often leads to a limited response and, subsequently, to the emergence of resistance. Therefore, to increase the overall effectiveness of antitumor drugs, it is advisable to use multitarget agents that can simultaneously suppress several key processes in the tumor cell. This review is focused on a group of plant-derived natural compounds that simultaneously target different pathways of cancer-associated metabolism, including aerobic glycolysis, respiration, glutaminolysis, one-carbon metabolism, de novo lipogenesis, and β-oxidation of fatty acids. We discuss only those compounds that display inhibitory activity against several metabolic pathways as well as a number of important signaling pathways in cancer. Information about their pharmacokinetics in animals and humans is also presented. Taken together, a number of known plant-derived compounds may target multiple metabolic and signaling pathways in various malignancies, something that bears great potential for the further improvement of antineoplastic therapy.

CDKN2A was a cuproptosis-related gene in regulating chemotherapy resistance by the MAGE-A family in breast cancer: based on artificial intelligence (AI)-constructed pan-cancer risk model

BACKGROUND

Before the discovery of cuproptosis, copper-loaded nanoparticle is a wildly applied strategy for enhancing the tumor-cell-killing effect of chemotherapy. Although copper(ii)-related researches are wide, details of cuproptosis-related bioprocess in pan-cancer are not clear yet now, especially for prognosis and drug sensitivity prediction yet now.

METHODS

In this study, VOSviewer is used for the literature review, and R4.2.0 is used for data analysis. Public data are collected from TCGA and GEO, local breast cancer cohort is collected to verify the expression level of CDKN2A.

RESULTS

7036 published articles exhibited a time-dependent linear relationship (R=0.9781, p<0.0001), and breast cancer (33.4%) is the most researched topic. Cuproptosis-related-genes (CRGs)-based unsupervised clustering divides pan-cancer subgroups into four groups (CRG subgroup) with differences in prognosis and tumor immunity. 44 tumor-driver-genes (TDGs)-based prediction model of drug sensitivity and prognosis is constructed by artificial intelligence (AI). Based on TDGs and clinical features, a nomogram is (C- index: 0.7, p= 6.958e- 12) constructed to predict the prognosis of breast cancer. Importance analysis identifies CDKN2A has a pivotal role in AI modeling, whose higher expression indicates worse prognosis in breast cancer. Furthermore, inhibition of CDKN2A down-regulates decreases Snail1, Twist1, Zeb1, vimentin and MMP9, while E-cadherin is increased. Besides, inhibition of CDKN2A also decreases the expression of MEGEA4, phosphorylated STAT3, PD-L1, and caspase3, while cleaved-caspase3 is increased. Finally, we find down-regulation of CDKN2A or MAGEA inhibits cell migration and wound healing, respectively.

CONCLUSIONS

AI identified CRG subgroups in pan-cancer based on CRGs-related TDGs, and 44-gene-based AI modeling is a novel tool to identify chemotherapy sensitivity in breast cancer, in which CDKN2A/MAGEA4 pathway played the most important role.

KITENIN promotes aerobic glycolysis through PKM2 induction by upregulating the c-Myc/hnRNPs axis in colorectal cancer

PURPOSE

The oncoprotein KAI1 C-terminal interacting tetraspanin (KITENIN; vang-like 1) promotes cell metastasis, invasion, and angiogenesis, resulting in shorter survival times in cancer patients. Here, we aimed to determine the effects of KITENIN on the energy metabolism of human colorectal cancer cells.

EXPERIMENTAL DESIGN

The effects of KITENIN on energy metabolism were evaluated using in vitro assays. The GEPIA web tool was used to extrapolate the clinical relevance of KITENIN in cancer cell metabolism. The bioavailability and effect of the disintegrator of KITENIN complex compounds were evaluated by LC-MS, in vivo animal assay.

RESULTS

KITENIN markedly upregulated the glycolytic proton efflux rate and aerobic glycolysis by increasing the expression of GLUT1, HK2, PKM2, and LDHA. β-catenin, CD44, CyclinD1 and HIF-1A, including c-Myc, were upregulated by KITENIN expression. In addition, KITENIN promoted nuclear PKM2 and PKM2-induced transactivation, which in turn, increased the expression of downstream mediators. This was found to be mediated through an effect of c-Myc on the transcription of hnRNP isoforms and a switch to the M2 isoform of pyruvate kinase, which increased aerobic glycolysis. The disintegration of KITENIN complex by silencing the KITENIN or MYO1D downregulated aerobic glycolysis. The disintegrator of KITENIN complex compound DKC1125 and its optimized form, DKC-C14S, exhibited the inhibition activity of KITENIN-mediated aerobic glycolysis in vitro and in vivo.

CONCLUSIONS

The oncoprotein KITENIN induces PKM2-mediated aerobic glycolysis by upregulating the c-Myc/hnRNPs axis.

The effects of MYC on exosomes derived from cancer cells in the context of breast cancer

MYC amplification and overexpression in breast cancer occur 16% and 22%, respectively, and MYC has a linchpin role in breast carcinogenesis. Emerging evidence has started to shed light on central role of MYC in breast cancer progression. On the contrary, tumor-derived exosomes and their cargo molecules are required for the modulation of the tumor environment and to promote carcinogenesis. Still, how MYC regulates tumor-derived exosomes is still a matter of investigation in the context of breast cancer. Here, we investigated for the first time how MYC affects the biological functions of normal breast cells cocultured with exosomes derived from MYC-expression manipulated breast cancer cells. Accordingly, exosomes were isolated from MCF-7 and MDA-MB-231 cells that MYC expression was manipulated through siRNAs or lentiviral vectors by using exosome isolation reagent. Then, normal breast epithelial MCF-10A cells were treated with breast cancer cell-derived exosomes. The cellular activity of MCF-10A was investigated by cell growth assay, wound healing assay, and transwell assay. Our results suggested that MCF-10A cells treated with exosomes derived from MYC-overexpressing breast cancer cells demonstrated higher proliferation and migration capability compared with nontreated cells. Likewise, MCF-10A cells treated with exosomes derived from MYC-silenced cancer cells did not show high proliferation and invasive capacity. Overall, MYC can drive the functions of exosomes secreted from breast cancer cells. This may allow exploring a new mechanism how tumor cells regulate cancer progression and modulate tumor environment. The present study clears the way for further researches as in vivo studies and multi-omics that clarify exosomal content in an MYC-dependent manner.

Role of Glucose Metabolic Reprogramming in Breast Cancer Progression and Drug Resistance

The involvement of glucose metabolic reprogramming in breast cancer progression, metastasis, and therapy resistance has been increasingly appreciated. Studies in recent years have revealed molecular mechanisms by which glucose metabolic reprogramming regulates breast cancer. To date, despite a few metabolism-based drugs being tested in or en route to clinical trials, no drugs targeting glucose metabolism pathways have yet been approved to treat breast cancer. Here, we review the roles and mechanisms of action of glucose metabolic reprogramming in breast cancer progression and drug resistance. In addition, we summarize the currently available metabolic inhibitors targeting glucose metabolism and discuss the challenges and opportunities in targeting this pathway for breast cancer treatment.

Infantile hemangioma models: is the needle in a haystack?

Infantile hemangioma (IH) is the most prevalent benign vascular tumor in infants, with distinct disease stages and durations. Despite the fact that the majority of IHs can regress spontaneously, a small percentage can cause disfigurement or even be fatal. The mechanisms underlying the development of IH have not been fully elucidated. Establishing stable and reliable IH models provides a standardized experimental platform for elucidating its pathogenesis, thereby facilitating the development of new drugs and the identification of effective treatments. Common IH models include the cell suspension implantation model, the viral gene transfer model, the tissue block transplantation model, and the most recent three-dimensional (3D) microtumor model. This article summarizes the research progress and clinical utility of various IH models, as well as the benefits and drawbacks of each. Researchers should select distinct IH models based on their individual research objectives to achieve their anticipated experimental objectives, thereby increasing the clinical relevance of their findings.

SRSF5 Regulates the Expression of BQ323636.1 to Modulate Tamoxifen Resistance in ER-Positive Breast Cancer

About 70% of breast cancer patients are oestrogen receptor-positive (ER +ve). Adjuvant endocrine therapy using tamoxifen (TAM) is an effective approach for preventing local recurrence and metastasis. However, around half of the patients will eventually develop resistance. Overexpression of BQ323636.1 (BQ) is one of the mechanisms that confer TAM resistance. BQ is an alternative splice variant of NCOR2. The inclusion of exon 11 generates mRNA for NCOR2, while the exclusion of exon 11 produces mRNA for BQ. The expression of SRSF5 is low in TAM-resistant breast cancer cells. Modulation of SRSF5 can affect the alternative splicing of NCOR2 to produce BQ. In vitro and in vivo studies confirmed that the knockdown of SRSF5 enhanced BQ expression, and conferred TAM resistance; in contrast, SRSF5 overexpression reduced BQ expression and, thus, reversed TAM resistance. Clinical investigation using a tissue microarray confirmed the inverse correlation of SRSF5 and BQ. Low SRSF5 expression was associated with TAM resistance, local recurrence and metastasis. Survival analyses showed that low SRSF5 expression was associated with poorer prognosis. We showed that SRPK1 can interact with SRSF5 to phosphorylate it. Inhibition of SRPK1 by a small inhibitor, SRPKIN-1, suppressed the phosphorylation of SRSF5. This enhanced the proportion of SRSF5 interacting with exon 11 of NCOR2, reducing the production of BQ mRNA. As expected, SRPKIN-1 reduced TAM resistance. Our study confirms that SRSF5 is essential for BQ expression. Modulating the activity of SRSF5 in ER +ve breast cancer will be a potential approach to combating TAM resistance.

Shikonin reverses pyruvate kinase isoform M2-mediated propranolol resistance in infantile hemangioma through reactive oxygen species-induced autophagic dysfunction

Infantile hemangioma (IH) is the most common benign tumor in infancy. Propranolol, a nonselective β-adrenergic receptor blocker, is now the first-line therapy for IH. Recently, low sensitivity to propranolol therapy has become one major reason for the failure of IH treatment. However, the exact underlying mechanisms are yet to be fully elucidated. Here, we reported that pyruvate kinase isoform M2 (PKM2), an essential glycolytic enzyme, played a critical role in regulating the progression of IH and the therapeutic resistance of propranolol treatment. Shikonin reversed the propranolol resistance in hemangioma-derived endothelial cells and in hemangioma animal models. Moreover, shikonin combined with propranolol could induce excessive reactive oxygen species (ROS) accumulation and lead to autophagic dysfunction, which is essential for the enhanced therapeutic sensitivity of propranolol treatment. Taken together, our results indicated that PKM2 has a significant role in hemangiomas progression and therapeutic resistance; it could be a safe and effective therapeutic strategy for those hemangiomas with poor propranolol sensitivity combined with shikonin.

miR-140-3p/usp36 axis mediates ubiquitination to regulate PKM2 and suppressed the malignant biological behavior of breast cancer through Warburg effect

Breast cancer is a phenomenon in which breast epithelial cells proliferate out of control under the action of various carcinogenic factors. However, the role of USP36 in breast cancer is unknown. We analyzed the expression of USP36 in breast cancer and its association with poor prognosis in breast cancer patients. The effect of USP36 on malignant biological behavior of breast cancer was verified by cell functional experiments. The upstream regulatory mechanism of USP36 was analyzed by Western blot and quantitative RT-qPCR. The influence of USP36 on the Warburg effect of breast cancer was analyzed by detecting the metabolism of cellular energy substances. We found that USP36 is highly expressed in breast tumor tissues and breast cancer cell lines. High expression of USP36 predicts poor prognosis in patients with breast cancer. Effectively reducing the expression of USP36 can significantly inhibit the proliferation, invasion and migration of breast cancer cells, and promote the apoptosis of breast cancer cells. Meanwhile, inhibiting the expression of USP36 can significantly inhibit the production of ATP, lactate, pyruvate and glucose uptake in breast cancer cells. miR-140-3p is an upstream regulator of USP36, which can partially reverse the regulatory effect of USP36 on breast cancer cells. Importantly, USP36 regulates the expression of PKM2 through ubiquitination, which plays a role in regulating the Warburg effect. We confirmed that miR-140-3p regulates the expression of USP36, which mediates ubiquitination and regulates the expression of PKM2, and regulates the malignant biological behavior of breast cancer through the energy metabolism process.

POR overexpression induces tamoxifen-resistance in breast cancer through the STAT1/c-Myc pathway

Breast cancer is the most common cancer in women worldwide. Although tamoxifen (TAM), a selective estrogen receptor (ER) modulator, is widely used to treat ER-positive breast cancers, resistance to TAM remains a major clinical problem. NADPH-dependent cytochrome P450 reductase (POR) is known to participate in drug metabolism and steroid metabolism. Recent studies showed that high POR expression was correlated with poor outcomes in triple-negative breast cancer (TNBC), and POR might be a prognostic biomarker in TNBC. However, the role of POR in TAM resistance is still elusive. In this study, we found that high POR expression was associated with poor prognosis of ER-positive and TAM-treated breast cancer patients. In addition, COX analysis showed that POR expression was an independent prognostic biomarker for ER-positive as well as TAM-treated breast cancer patients. Furthermore, our results suggested that POR overexpression promoted TAM resistance by activating the STAT1/c-Myc pathway in ER-positive breast cancer cells. Immunohistochemical analysis showed that high POR/STAT1 expression was correlated with poor prognosis in TAM-treated breast cancer patients. Notably, combined treatment with TAM and a specific STAT1 inhibitor Fludarabine was more effective for inhibiting TAM-resistant breast cancer cells. Altogether, our findings suggested that POR overexpression induced TAM resistance through STAT1/c-Myc pathway and might serve as an independent prognostic biomarker in TAM-treated breast cancer patients. Combining TAM and STAT1 inhibitors might be an effective strategy for treating POR-induced TAM-resistant breast cancer.

Ubiquitin specific protease 46 potentiates triple negative breast cancer development by stabilizing PGAM1-mediated glycolysis

Triple-negative breast cancer (TNBC) is a malignancy with high metastasis rate and poor prognosis. Limited drugs are effective for the treatment of TNBC patients. Ubiquitin specific proteases (USPs) are important posttranscription modulators that promote protein stability by reducing the ubiquitination of the proteins. Aberrant expression of USPs is involved in the development of numerous cancers. However, it remains poorly understood on the role of USP46 in TNBC growth and metastasis. In this study, we explored the clinical relevance, function and molecular mechanisms of USP46 in TNBC. USP46 expression was increased in breast cancer tissues. High expression of USP46 was associated with the poorer prognosis of the patients. Overexpression and knockdown experiments demonstrated that USP46 was critical for TNBC cell growth, migration, and tumorigenesis. Mechanistically, USP46 enhanced the protein stability of phosphoglycerate mutase 1 (PGAM1) via direct interaction. Importantly, USP46 stimulated the glycolysis and promoted the malignant growth of TNBC cells through upregulation of PGAM1. Our study reveals that USP46/PGAM1 axis contributes to TNBC progression and is a potential target for the treatment of TNBC patients.

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.

The cancer stemness inhibitor napabucasin suppresses small cell lung cancer growth through SOX2 expression

Small cell lung cancer (SCLC) is a high-grade malignancy of neuroendocrine origin characterized by aggressive cell growth and a poor survival rate of patients. Currently, the treatment options for SCLC remain limited despite platinum-based chemotherapy. Systemic chemotherapy is effective for SCLC, but most patients eventually acquire drug resistance, which leads to treatment failure. Stemness-high cancer cells show characteristics of advanced tumorigenesis and metastasis and have high potential in promoting treatment resistance and disease relapse. Napabucasin (BBI608), a novel small-molecule drug targeting on signal transducer and activator of transcription 3 (STAT3), was shown to suppress the progression and metastasis of stemness-high cancer stem cells in various cancers. Here, we demonstrated that napabucasin significantly decreased viability and colony formation and induced the arrest of S-phase cell cycle and apoptosis in cisplatin-resistant SCLC cells. Findings from mechanistic studies further indicated that napabucasin directly downregulated the expression of SOX2 in cisplatin-resistant SCLC cells; however, dysfunctional SOX2 expression in SCLC cells was associated with interference in the napabucasin-mediated reduction of cell viability. In contrast, napabucasin-induced viability reduction was restored in these cells when SOX2 expression was upregulated. Furthermore, napabucasin significantly inhibited cisplatin-resistant SCLC cell xenograft growth in vivo by downregulating SOX2 and inducing apoptosis. These data demonstrate that napabucasin may be a novel drug for the clinical treatment of cisplatin-resistant SCLC.

Optimization of Bifunctional Antisense Oligonucleotides for Regulation of Mutually Exclusive Alternative Splicing of PKM Gene

Oligonucleotide tools, as modulators of alternative splicing, have been extensively studied, giving a rise to new therapeutic approaches. In this article, we report detailed research on the optimization of bifunctional antisense oligonucleotides (BASOs), which are targeted towards interactions with hnRNP A1 protein. We performed a binding screening assay, Kd determination, and UV melting experiments to select sequences that can be used as a high potency binding platform for hnRNP A1. Newly designed BASOs were applied to regulate the mutually exclusive alternative splicing of the PKM gene. Our studies demonstrate that at least three repetitions of regulatory sequence are necessary to increase expression of the PKM1 isoform. On the other hand, PKM2 expression can be inhibited by a lower number of regulatory sequences. Importantly, a novel branched type of BASOs was developed, which significantly increased the efficiency of splicing modulation. Herein, we provide new insights into BASOs design and show, for the first time, the possibility to regulate mutually exclusive alternative splicing via BASOs.

3‑Bromopyruvic acid regulates glucose metabolism by targeting the c‑Myc/TXNIP axis and induces mitochondria‑mediated apoptosis in TNBC cells

Aerobic glycolysis is commonly observed in tumor cells, including triple-negative breast cancer (TNBC) cells, and the rate of aerobic glycolysis is higher in TNBC cells than in non-TNBC cells. Hexokinase 2 (HK2) is a key enzyme in the glycolytic pathway and a target of the transcription factor c-Myc, which is highly expressed in TNBC and promotes aerobic glycolysis by enhancing HK2 expression. As an inhibitor of HK2, 3-bromopyruvic acid (3-BrPA) exhibits good therapeutic efficacy in intrahepatic and extrahepatic tumors and inhibits the proliferation of human tumor cells with high expression levels of c-Myc in vivo and in vitro. In addition, 3-BrPA combines with photodynamic therapy to inhibit TNBC cell migration. Thioredoxin-interacting protein (TXNIP) competes with c-Myc to reduce glucose consumption in tumor cells to restrain cell proliferation. A comparative analysis was performed in the present study in TNBC (HCC1143) and non-TNBC (MCF-7) cell lines to explore the effect of 3-BrPA on energy metabolism in TNBC cells and to investigate the possible mechanism of action. Cell viability and apoptosis were detected through Cell Counting Kit-8 and flow cytometry assays, respectively. Expression levels of HK2, glucose transporter 1, TXNIP, c-Myc and mitochondria-regulated apoptosis pathway proteins were measured through western blotting. 3-BrPA inhibited cell proliferation, downregulated c-Myc and HK2 expression, and upregulated TXNIP expression in TNBC cells, but it doesn't have the same effect on non-TNBC cells. Furthermore, 3-BrPA induced the typical manifestations of mitochondrial-mediated apoptosis such as decreasing Bcl-2 expression and increasing Bax, Cyt-C and Caspase-3 expression. The present results suggested that 3-BrPA promoted TXNIP protein expression and reduced HK2 expression in TNBC cells by downregulating c-Myc expression, inhibiting glycolysis including suppressing lactate generation, intracellular ATP generation and HK activity, inducing mitochondrial-mediated apoptosis and eventually suppressing TNBC cell proliferation. These findings may reveal a novel therapeutic target for the clinical treatment of TNBC.

Targeting Ribosome Biogenesis to Combat Tamoxifen Resistance in ER+ve Breast Cancer

Simple Summary

Resistance to tamoxifen treatment is an obstacle for ER+ve breast cancer therapy. The overexpression of c-MYC is a known driver of cancer progression and is associated with tamoxifen resistance. Through mediating the up-regulation of ribosome biogenesis and alteration of the transcriptome, c-MYC modulates the translation profile to facilitate the development of tamoxifen resistance. c-MYC is, however, undruggable. Thus, targeting downstream mechanisms mediated by c-MYC might be a more feasible approach. Studies have demonstrated that inhibition of ribosome biogenesis can achieve tumour suppression. Targeting ribosome biogenesis may thus be a feasible strategy to reverse tamoxifen resistance. This article reviews the current evidence to support the feasibility of suppressing ribosome biogenesis to reverse tamoxifen resistance in ER+ve breast cancer.

Abstract

Breast cancer is a heterogeneous disease. Around 70% of breast cancers are estrogen receptor-positive (ER+ve), with tamoxifen being most commonly used as an adjuvant treatment to prevent recurrence and metastasis. However, half of the patients will eventually develop tamoxifen resistance. The overexpression of c-MYC can drive the development of ER+ve breast cancer and confer tamoxifen resistance through multiple pathways. One key mechanism is to enhance ribosome biogenesis, synthesising mature ribosomes. The over-production of ribosomes sustains the demand for proteins necessary to maintain a high cell proliferation rate and combat apoptosis induced by therapeutic agents. c-MYC overexpression can induce the expression of eIF4E that favours the translation of structured mRNA to produce oncogenic factors that promote cell proliferation and confer tamoxifen resistance. Either non-phosphorylated or phosphorylated eIF4E can mediate such an effect. Since ribosomes play an essential role in c-MYC-mediated cancer development, suppressing ribosome biogenesis may help reduce aggressiveness and reverse tamoxifen resistance in breast cancer. CX-5461, CX-3543 and haemanthamine have been shown to repress ribosome biogenesis. Using these chemicals might help reverse tamoxifen resistance in ER+ve breast cancer, provided that c-MYC-mediated ribosome biogenesis is the crucial factor for tamoxifen resistance. To employ these ribosome biogenesis inhibitors to combat tamoxifen resistance in the future, identification of predictive markers will be necessary.

Clinical Significance of Circulating Tumor Cells (CTCs) and Survivin on Predicting Prognosis in Thyroid Cancer Patients

Background. Clinical significance of circulating tumor cell (CTC) count, mesenchymal CTCs (MCTCs), and survivin in patients with thyroid cancer remains unclear. We evaluated the relationship between the expression of different CTC subtypes or survivin and the prognosis in patients with thyroid cancer. Patients and Methods. This study enrolled 164 patients with thyroid cancer who were diagnosed from January 2013 to September 2020 in our hospital. Among these patients, there were 73 cases with papillary thyroid cancer (PTC), 60 cases with follicular thyroid cancer (FTC), 12 medullary thyroid cancers (MTC), 10 poorly differentiated thyroid cancers (PDTC), 9 anaplastic thyroid cancers, and 10 control patients with nonmalignant thyroid nodules based on their histopathological characteristics. Only 5 milliliters (mL) of peripheral blood from the patients with thyroid cancer and control was used to detect the CTC cell number via CanPatrol capture technique before treatments. We also isolated mononuclear cells (MNC) from the peripheral blood and performed quantity reverse transcriptase polymerase chain reaction (qPCR) for survivin gene expression among these patients. Results. The overall positive rates of CTC at diagnosis were 56.1%. The relapse and metastasis rates in PTC and FTC patients with more than 6 CTCs and positive MCTCs were significantly higher than those in the patients with 6 or less than 6 CTCs and MCTCs. It was also found that these patients with >6 CTCs and MCTCs had shorter progression-free survival (PFS). Additionally, the survivin level of the patients with thyroid cancer was strongly relative to differentiation grades of thyroid cancers. Conclusions. The detection of more than six of total CTCs and positive MCTCs in the patients with differentiated thyroid cancer is an excellent biomarker for predicting the prognosis of patients. Survivin also is a good biomarker for thyroid cancer differentiation.

Metabolic Reprogramming Underlying Brain Metastasis of Breast Cancer

The development of brain metastasis is a major cause of death in patients with breast cancer, characterized by rapid progression of the disease and poor prognosis, and lack of effective treatment has existed as an unresolved issue clinically. Extensive research has shown that a variety of metabolic changes associated with cellular metastasis exist in primary breast cancer or brain metastases, therefore to elucidate metabolic characteristics at each step of the metastasis cascade will provide important clues to the efficient treatment. In this review, we discuss the changes in metabolic patterns of breast cancer cells at every step of metastasis for exploring the potential therapeutic target based on metabolic reprogramming, and provide new insights on the design and development of drugs for breast cancer brain metastasis.

Therapeutic targeting of chromatin: status and opportunities

The molecular characterization of mechanisms underlying transcriptional control and epigenetic inheritance since the 1990s has paved the way for the development of targeted therapies that modulate these pathways. In the past two decades, cancer genome sequencing approaches have uncovered a plethora of mutations in chromatin modifying enzymes across tumor types, and systematic genetic screens have identified many of these proteins as specific vulnerabilities in certain cancers. Now is the time when many of these basic and translational efforts start to bear fruit and more and more chromatin-targeting drugs are entering the clinic. At the same time, novel pharmacological approaches harbor the potential to modulate chromatin in unprecedented fashion, thus generating entirely novel opportunities. Here, we review the current status of chromatin targets in oncology and describe a vision for the epigenome-modulating drugs of the future.

Long non-coding RNAs in breast cancer metastasis

Breast cancer is the leading cause of cancer-related death among women. Recurrence of primary tumor and metastasis to distant body parts are major causes of breast cancer-associated mortality. The 5-year survival rate for women with metastatic breast cancer is only 25-30%. Breast cancer metastasis is a series of processes involved with EMT, invasion, loss of cell to cell adhesion, alteration in cell phenotype, extravasation, microenvironment of the tumor, and colonization to the secondary sites. Epigenetic modification is involved in the transformation of the distant stromal cell into a secondary tumor. LncRNAs, are one the key epigenetic modifiers, are the largest endogenous non-coding RNAs with approximate base-pair lengths from 200 nt to 100 kb. LncRNA plays a crucial role in breast cancer metastasis by sponging miRNA, by degrading or silencing specific mRNA, or else by targeting the enzymes and microprocessor subunits involved in the biogenesis of miRNA. LncRNA also alters the expression of several genes involved in breast cancer metastasis and modulating different cell signaling pathways. The goal of this review is to provide a better understanding of the role of lncRNA in the regulation of breast cancer metastasis. We also summarized some of the key lncRNAs that regulate the genes and signaling pathways involved in breast cancer invasion and metastasis.