Induced Cancer Cell Proliferation Research Articles

Expression of Pluripotency Factors OCT4 and LIN28 Correlates with Survival Outcome in Lung Adenocarcinoma.

Background and Objectives: Lung adenocarcinoma is a leading cause of cancer-related mortality despite recent therapeutic advances. Cancer stem cells have gained increasing attention due to their ability to induce cancer cell proliferation through self-renewal and differentiation into multiple cell lineages. OCT4 and LIN28 (and their homologs A and B) have been identified as key regulators of pluripotency in mammalian embryonic (ES) and induced stem (IS) cells, and they are the crucial regulators of cancer progression. However, their exact role in lung adenocarcinoma has not yet been clarified. Materials and Methods: The aim of this study was to explore the role of the pluripotency factors OCT4 and LIN28 in a cohort of surgically resected human lung adenocarcinomas to reveal possible biomarkers for lung adenocarcinoma prognosis and potential therapeutic targets. The expressions of OCT4, LIN28A and LIN28B were analyzed in formalin-fixed, paraffin-embedded tissue samples from 96 patients with lung adenocarcinoma by immunohistochemistry. The results were analyzed with clinicopathologic parameters and were related to the prognosis of patients. Results: Higher OCT4 expression was related to an improved 5-year overall survival (OS) rate (p < 0.001). Nuclear LIN28B expression was lower in stage I and II tumors (p < 0.05) compared to advanced stage tumors. LIN28B cytoplasmic expression was associated with 5-year OS rates not only in univariate (p < 0.005), but also in multivariate analysis (where age, gender, histopathological subtype and stage were used as cofactors, p < 0.01 HR = 2.592). Patients with lower LIN28B expression showed improved 5-year OS rates compared to patients with increased LIN28B expression. Conclusions: Our findings indicate that OCT4 and LIN28B are implicated in lung adenocarcinoma progression and prognosis outcome; thus, they serve as promising prognostic biomarkers and putative therapeutic targets in lung adenocarcinomas.

PRMT5-mediated methylation of STAT3 is required for lung cancer stem cell maintenance and tumour growth.

STAT3 is constitutively activated in many cancer types, including lung cancer, and can induce cancer cell proliferation and cancer stem cell (CSC) maintenance. STAT3 is activated by tyrosine kinases, such as JAK and SRC, but the mechanism by which STAT3 maintains its activated state in cancer cells remains unclear. Here, we show that PRMT5 directly methylates STAT3 and enhances its activated tyrosine phosphorylation in non-small cell lung cancer (NSCLC) cells. PRMT5 expression is also induced by STAT3, suggesting the presence of a positive feedback loop in cancer cells. Furthermore, methylation of STAT3 at arginine 609 by PRMT5 is important for its transcriptional activity and support of tumour growth and CSC maintenance. Indeed, NSCLC cells expressing the STAT3 mutantwhich R609 was replaced to alanine (R609K)show significantly impaired tumour growth in nude mice. Overall, our study reveals a mechanism by which STAT3 remains activated in NSCLC and provides a new target for cancer therapeutic approaches.

Abstract PR-010: Dual targeting of IDO1/TDO2 inhibits tumor progression and attenuates the immune suppressive tumor microenvironment

Abstract Introduction: High-grade serous carcinoma (HGSC) tumors of the ovary, fallopian tube, or peritoneum are predicted to be immunogenic since the presence of tumor-infiltrating lymphocytes conveys a better prognosis. However, the efficacy of immunotherapies has been limited due to the immune-suppressed tumor immune microenvironment (TIME), which is established through tumor metabolism and immune-suppressive metabolites that directly affect immune cell function by depleting nutrients and activating immune-suppressive transcriptional programs. The tryptophan (TRP) catabolism pathway is a critical regulator of immune-suppressed TIME; however, clinical trials targeting the pathway to date have demonstrated limited response. Note there are two structurally distinct rate-limiting TRP catabolizing enzymes, Indoleamine 2,3-Dioxygenase (IDO1) and Tryptophan 2,3-Dioxygenase (TDO2), that evolved separately to catabolize tryptophan into Kynurenine (KYN). Most TRP catabolism inhibitors (e.g., Epacadostat) have primarily targeted IDO1, which may explain the mild anti-tumor effects of Epacadostat. Thus, we hypothesize that targeting both enzymes involved in TRP catabolism will alleviate the immune-suppressed TIME. Methods: We assessed primary human ascites fluid (IRB #07-0395) with global untargeted metabolomics. Using a panel of HGSC cell lines, we assessed genetic (small hairpin-mediated knockdown and overexpression) and pharmacologic (Epacadostat [IDO1 inhibitor], AT-0174 [IDO1/TDO2 inhibitor], 66cl4 [TDO2 inhibitor], StemRegenin 1 [AhR inhibitor]) modulation of IDO1, TDO2, and aryl hydrocarbon receptor (AhR, signal transducer of KYN). Proliferation assays in 2D and 3D. We examined the response of IDO1/TDO2 inhibition in two syngeneic murine models (ID8 Tp53-/- and BR-Luc Tp53-/-, Brca1-/-, myr-AKT, MYC). Multispectral immunohistochemistry (mIHC) and flow cytometry defined the TIME. Results: Elevated KYN levels are correlated to an inflamed TIME. The depletion of TRP and increased KYN negatively affect the anti-tumor immune response. HGSC cell lines and clinical outcomes depend more on TDO2 than IDO1. In contrast to knocking down IDO1 and AhR, TDO2 knockdown inhibited HGSC cell growth, and overexpression of TDO2 induced cancer cell proliferation. Targeting both IDO1 and TDO2 significantly inhibited TRP catabolism. Notably, only the combined IDO1/TDO2 inhibition resulted in the downregulation of PD-L1. In a syngeneic HGSC murine model, a first-in-class orally available dual IDO1/TDO2 inhibitor (AT-0174) significantly inhibited tumor progression, reduced tumor-associated macrophages, and reduced expression of immune-suppressive proteins, including PD-L1, on immune and tumor cells. Conclusions: These studies demonstrate the importance of TDO2 and the potential of AT-0174 to overcome an immune-suppressed TIME. The findings represent a novel approach to targeting TRP catabolism that may improve tumor response rates to immune therapy. Citation Format: Lyndsey Crump, Jessica Floyd, Elizabeth Woodruff, Mike Bickerdike, Li-Wei Kuo, Miriam Post, Silviu Itescu, Jennifer Richer, Benjamin G. Bitler. Dual targeting of IDO1/TDO2 inhibits tumor progression and attenuates the immune suppressive tumor microenvironment [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr PR-010.

Abstract 2550: Growth factor-induced cell membrane macroplatforms drive protein kinase signaling for transformed cell growth

Abstract Nanoscopic, millisecond-lasting membrane platforms are modeled to constitute main functional signaling units. However, multiple signaling events in cell growth induction, including receptor Tyr-kinase (RTK) stimulation, calcium signaling, cytoplasmic kinase recruitment, operate over much broader space-time frames. Through dynamic confocal/super-resolution/electron-microscopy on living cells, we discovered that signaling competence is acquired through growth factor-induced coalescence of activated growth inducers (RTK, CD9, CD81, CD98, Co-029, CD316, Trop-1, Trop-2, PI3K, PI4K), and downstream effectors (Grb-2, PKCα, ERK, Akt, Src, Syk, ILK, ezrin) into confined segments of the cell membrane (‘docks’), that recursively assemble over hundreds of seconds. Average size (25±5 μm; ~80,000 individual analyses) and lifetime (222±25 sec) of docks extend by orders of magnitude previously recognized space-time frames for cell signaling. Activated/phosphorylated kinases clustered at membrane docks (99% P-Erb-B4; 91% P-Ret; 90% P-PKCα; 90% P-Src). STED super-resolution microscopy revealed up to 10 µm2 signal transducer areas of effector colocalization. Docks &amp;gt;1.0 µm2 accounted for ~90% of colocalizations versus ≈1% of raft-sized domains (&amp;lt;0.005 µm2). FRET-FLIM subsequently indicated that inter-molecular signal transducer interactions are essentially confined at docks. Docks were induced by growth factors (FGF-1, PDGF, EGF&amp;gt;HGF, IGF-1&amp;gt;&amp;gt;SCF/VEGF), were inhibited by Tyr kinase and cytoskeleton inhibitors, and were shown to induce cancer cell proliferation. Citation Format: Saverio Alberti, Valeria Relli, Romina Tripaldi, Pasquale Simeone, Emanuela Guerra, Andrea Sacchetti, Paolo Ciufici, Antonino Moschella, Valeria Caiolfa, Moreno Zamai, Marco Trerotola. Growth factor-induced cell membrane macroplatforms drive protein kinase signaling for transformed cell growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2550.

Oncogene-mediated nuclear accumulation of lactate promotes epigenetic alterations to induce cancer cell proliferation.

Homeobox gene families are associated with embryonic development and organogenesis. Pieces of evidence suggest that these Homeobox genes are also crucial in facilitating oncogenesis when mutated or overexpressed. Paired homeodomain transcription factor-2 (PITX2), one of the members of this family, is involved in oncogenic regulation apart from its different development regulatory functions. PITX2 has been earlier shown to induce ovarian cancer cell proliferation through the activation of different signaling cascades. Increased cancer cell proliferation requires a constant supply of nutrients for both adenosine triphosphate and biomass synthesis, which is facilitated by altered cancer cell metabolism that includes enhanced glucose uptake and increased glycolytic rate. This present study highlights the involvement of PITX2 in enhancing the cellular glycolysis pathway in ovarian cancer cells through protein kinase B-phosphorylation (phospho-AKT). PITX2 expression correlates positively with that of the glycolytic rate-determining enzyme, lactate dehydrogenase-A (LDHA), in both high-grade serous ovarian cancer tissues and common ovarian cancer cell lines. Interestingly, transient localization of enzymatically active LDHA in the nucleus was observed in PITX2-overexpressed ovarian cancer cells. This nuclear LDHA produces higher concentrations of the glycolytic end product, lactate, which accumulates in the nuclear compartment resulting in decreased histone deacetylase (HDAC1/2) expression and increased histone acetylation at H3/H4. However, the mechanistic details of lactate-HDAC interaction are still elusive in the earlier reports. Our in silico studies elaborated on the interaction dynamics of lactate in the HDAC catalytic core through ligand-binding studies and molecular dynamics simulation approaches. Blocking lactate production by silencing LDHA reduced cancer cell proliferation. Thus, PITX2-induced epigenetic changes can lead to high cellular proliferation and increase the size of tumors in syngeneic mice as well. Taken together, this is the first report of its kind to show that the developmental regulatory homeobox gene PITX2 could enhance oncogenesis through enhanced glycolysis of tumor cells followed by epigenetic modifications.

Abstract 2435: EZH2 engages TGFb signaling to promote breast cancer bone metastasis via Integrin b1-FAK activation

Abstract Bone metastasis is a frequent complication of breast cancer, occurring in about 50-70% of breast cancer patients with late-stage disease. The lack of effective therapy suggests that the precise molecular mechanisms underlying bone metastasis are still unclear. Enhancer of zeste homolog 2 (EZH2) is considered a breast cancer oncogene and its expression is correlated with metastasis of breast cancer, but its function in bone metastasis has not been well explored. Herein we report that EZH2 promotes osteolytic metastasis of breast cancer through regulating transforming growth factor beta (TGFβ) signaling, a key pathway in bone metastasis. Knocking down EZH2 decreases bone metastasis incidence and outgrowth in vivo. EZH2 induces cancer cell proliferation and osteoclast maturation, when breast cancer cells are co-cultured with osteoblasts and osteoclasts together in vitro. Mechanistically, EZH2 increases transcription of ITGB1, which encodes for integrin β1. Integrin β1 activates focal adhesion kinase (FAK), which phosphorylates TGFβ receptor type I (TGFβRI) at tyrosine 182, thus enhances the binding of TGFβRI to TGFβ receptor type II (TGFβRII), therefore activates Smad2 and increases parathyroid hormone-like hormone (PTHLH) expression. Clinically applicable FAK inhibitors but not EZH2 methyltransferase inhibitor effectively inhibits breast cancer bone metastasis in vivo. Overall, our data signify integrin β1-FAK as a new downstream effector of EZH2 in breast cancer cells, and EZH2-integrin β1-FAK axis cooperates with TGFβ signaling pathway to promote bone metastasis of breast cancer. Citation Format: Lin Zhang, Jingkun Qu, Yutao Qi, Yimin Duan, Yu-Wen Huang, Zhifen Zhou, Ping Li, Jun Yao, Beibei Huang, Shuxing Zhang, Dihua Yu. EZH2 engages TGFb signaling to promote breast cancer bone metastasis via Integrin b1-FAK activation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2435.

EZH2 engages TGFβ signaling to promote breast cancer bone metastasis via integrin β1-FAK activation

Bone metastases occur in 50–70% of patients with late-stage breast cancers and effective therapies are needed. The expression of enhancer of zeste homolog 2 (EZH2) is correlated with breast cancer metastasis, but its function in bone metastasis hasn’t been well-explored. Here we report that EZH2 promotes osteolytic metastasis of breast cancer through regulating transforming growth factor beta (TGFβ) signaling. EZH2 induces cancer cell proliferation and osteoclast maturation, whereas EZH2 knockdown decreases bone metastasis incidence and outgrowth in vivo. Mechanistically, EZH2 transcriptionally increases ITGB1, which encodes for integrin β1. Integrin β1 activates focal adhesion kinase (FAK), which phosphorylates TGFβ receptor type I (TGFβRI) at tyrosine 182 to enhance its binding to TGFβ receptor type II (TGFβRII), thereby activating TGFβ signaling. Clinically applicable FAK inhibitors but not EZH2 methyltransferase inhibitors effectively inhibit breast cancer bone metastasis in vivo. Overall, we find that the EZH2-integrin β1-FAK axis cooperates with the TGFβ signaling pathway to promote bone metastasis of breast cancer.

3P Targeting pancreatic adenocarcinoma upregulated factor (PAUF) to treat pancreatic cancer (PC): In vivo efficacy and safety of PBP1510, a first in class monoclonal antibody (mAb)

PAUF plays a key role in PC tumour progression and metastasis by inducing cancer cell proliferation, angiogenesis and evasion of immune surveillance. PBP1510 developed by Prestige Biopharma Limited, is a novel humanized IgG1 mAb that binds to and neutralizes PAUF with high specificity and affinity. There are no targeted therapies against PAUF, making PBP1510 the first in this class.

Histone acetyltransferases CBP/p300 in tumorigenesis and CBP/p300 inhibitors as promising novel anticancer agents.

The histone acetyltransferases CBP and p300, often referred to as CBP/p300 due to their sequence homology and functional overlap and co-operation, are emerging as critical drivers of oncogenesis in the past several years. CBP/p300 induces histone H3 lysine 27 acetylation (H3K27ac) at target gene promoters, enhancers and super-enhancers, thereby activating gene transcription. While earlier studies indicate that CBP/p300 deletion/loss can promote tumorigenesis, CBP/p300 have more recently been shown to be over-expressed in cancer cells and drug-resistant cancer cells, activate oncogene transcription and induce cancer cell proliferation, survival, tumorigenesis, metastasis, immune evasion and drug-resistance. Small molecule CBP/p300 histone acetyltransferase inhibitors, bromodomain inhibitors, CBP/p300 and BET bromodomain dual inhibitors and p300 protein degraders have recently been discovered. The CBP/p300 inhibitors and degraders reduce H3K27ac, down-regulate oncogene transcription, induce cancer cell growth inhibition and cell death, activate immune response, overcome drug resistance and suppress tumor progression in vivo. In addition, CBP/p300 inhibitors enhance the anticancer efficacy of chemotherapy, radiotherapy and epigenetic anticancer agents, including BET bromodomain inhibitors; and the combination therapies exert substantial anticancer effects in mouse models of human cancers including drug-resistant cancers. Currently, two CBP/p300 inhibitors are under clinical evaluation in patients with advanced and drug-resistant solid tumors or hematological malignancies. In summary, CBP/p300 have recently been identified as critical tumorigenic drivers, and CBP/p300 inhibitors and protein degraders are emerging as promising novel anticancer agents for clinical translation.

Anticancer Effects of Midazolam on Lung and Breast Cancers by Inhibiting Cell Proliferation and Epithelial-Mesenchymal Transition.

Despite improvements in cancer treatments resulting in higher survival rates, the proliferation and metastasis of tumors still raise new questions in cancer therapy. Therefore, new drugs and strategies are still needed. Midazolam (MDZ) is a common sedative drug acting through the γ-aminobutyric acid receptor in the central nervous system and also binds to the peripheral benzodiazepine receptor (PBR) in peripheral tissues. Previous studies have shown that MDZ inhibits cancer cell proliferation but increases cancer cell apoptosis through different mechanisms. In this study, we investigated the possible anticancer mechanisms of MDZ on different cancer cell types. MDZ inhibited transforming growth factor β (TGF-β)-induced cancer cell proliferation of both A549 and MCF-7 cells. MDZ also inhibited TGF-β-induced cell migration, invasion, epithelial-mesenchymal-transition, and Smad phosphorylation in both cancer cell lines. Inhibition of PBR by PK11195 rescued the MDZ-inhibited cell proliferation, suggesting that MDZ worked through PBR to inhibit TGF-β pathway. Furthermore, MDZ inhibited proliferation, migration, invasion and levels of mesenchymal proteins in MDA-MD-231 triple-negative breast cancer cells. Together, MDZ inhibits cancer cell proliferation both in epithelial and mesenchymal types and EMT, indicating an important role for MDZ as a candidate to treat lung and breast cancers.

The interplay between reactive oxygen species and antioxidants in cancer progression and therapy: a narrative review.

ObjectiveTo unveil the role of reactive oxygen species (ROS) and antioxidants in signaling and involvement in cancer progression and therapy.BackgroundCancer is considered one of the main causes of mortality in developed countries and expected to be more in developing countries as well. Although some cancers may develop at young age, yet almost all types of cancers are an accumulation of genetic and epigenetic cell damages. Cancer is considered a diverse collection of diseases on a cellular level rather than a single disease; and each disease has a different cause as well. ROS have been seen as harmful toxic molecules; however, they are recognized for cellular signaling capabilities. Elevated levels of ROS have protumorigenic activities; they induce cancer cell proliferation, and adaptation to hypoxia in addition to other effects like DNA damage and genetic instability. They are produced excessively by cancer cells to hyperactivate cellular transformation meanwhile increasing antioxidant capacity to avoid cell death.MethodsWe discussed peer reviewed published research work from 1987 to 2021. In this paper, we review the role of antioxidants as defensive barrier against excessive ROS levels for maintaining oxidation-reduction (redox) balance; however, antioxidant can also strive in tumor cells with their scavenging capacities and maintain protumorigenic signaling and resist the cancer cell oxidative stress and apoptosis. High doses of antioxidant compounds could be toxic to cells as they are capable of reacting with the physiological concentrations of ROS present for normal cellular processes and signaling.ConclusionsMaintaining cellular redox homeostasis is vital for healthy biological system. Therefore, therapeutic modalities for cancer including antioxidants and ROS management should be used at certain doses to target specific redox pathways involved in cancer progression without disrupting the overall redox balance in normal cells.

Abstract 1346: Direct targeting of MAPK/ERK signaling pathway is a novel therapeutic approach for high-risk neuroblastoma

Abstract Neuroblastoma is a highly heterogenous pediatric tumor that develops during the early embryonic stages, and accounts for almost 15% of pediatric cancer related deaths. Despite advanced and intensive therapeutic approaches that combine surgery, radiation, and chemotherapy, high-risk neuroblastoma (NB) patients' long-term survival is still less than 50%. Tumor metastasis, relapse, drug-resistance, and treatment related toxicities mandate the development of novel therapeutic approaches to treat NB patients. MAPK/ERK pathway plays an important oncogenic role in different types of cancers, including NB. Activation of the MAPK/ERK pathway is known to induce cancer cell proliferation, progression, metabolism, and resistance to drug-induced apoptosis. In the present study, we investigated the effect of a small-molecule MEK inhibitor that targets MEK1 and MEK2 to block MAPK/ERK pathway in NB. Cytotoxicity assays using Cell-Titer One solution in different MYCN-amplified (NGP, LAN-5, CHLA-255-MYCN) and MYCN-non-amplified (SH-SY5Y, SK-N-AS, CHLA-255) NB cell lines show that MEK inhibitor significantly reduce the NB cell proliferation in a dose-dependent manner. We further performed clonogenic assays and 3D spheroidal assays to mimic the NB tumor growth, and our results show that MEK inhibitor significantly inhibit NB colony formation, inhibit 3D spheroidal tumor size by inducing cell death in 3D spheroidal tumors, in comparison to controls. Additionally, MEK inhibitor in a dose-dependent manner induces apoptosis and blocks cell cycle progression in NB cells in comparison to control, as determined by Annexin V apoptosis assays and Click-iT EdU cell proliferation assay respectively. Furthermore, gene expression analysis show that MEK inhibitor significantly reduce the mRNA expression of specific MAPK/ERK pathway targets such as MEK1, MEK2, and ERK2. Western blot assays further confirm the efficacy of MEK inhibitor in blocking MAPK/ERK pathway by significantly inhibiting the phosphorylation of key pathway proteins. Taken together, our results highlight that: a) MAPK/ERK pathway is implicated in NB growth, and b) direct targeting of MAPK/ERK signaling pathway by using a novel small molecule MEK inhibitor inhibit NB proliferation and 3D tumor growth. We will further combine this MEK inhibitor with current chemotherapy drugs to develop effective therapeutic approaches for NB patients. Citation Format: Rameswari Chilamakuri, Bharti Sharma, Danielle C. Rouse, Saurabh Agarwal. Direct targeting of MAPK/ERK signaling pathway is a novel therapeutic approach for high-risk neuroblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1346.

Vimentin loss promotes cancer proliferation through up-regulating Rictor/AKT/β-catenin signaling pathway

Vimentin protein is one of the main cytoskeleton and plays an important role in cell motility and metastasis. Nowadays, vimentin is widely studied as an epithelial-mesenchymal transition (EMT) marker of cancer cells while its involvement in cancer proliferation is poorly understood. In this study, we investigated the participation of vimentin in regulating cancer proliferation by silencing VIM gene in four cancer cell lines. Our results demonstrated that vimentin loss significantly induced cancer cell proliferation both in vitro and in vivo, which has not been reported so far. Mechanistically, knockdown of vimentin expression activated AKT phosphorylation and its downstream β-catenin signaling. Nuclear translocation and transcriptional activity of β-catenin was enhanced after silencing vimentin expression. Furthermore, vimentin loss could prevent Rictor from autophagy-dependent degradation via reducing AMPK-mediated autophagy signaling. AICAR, an AMPK activator, down-regulated Rictor and p-AKT levels while vimentin knockdown could rescue the effects. In vivo, it was also found that Ki67 expression and p-AKT/β-catenin signaling pathway were obviously up-regulated in the tumor tissues in which vimentin was silenced compared to control groups. Taken together, these data showed the novel function of vimentin in regulating cancer proliferation via Rictor/AKT/β-catenin signaling pathway, which suggested that it need more careful consideration before inhibiting metastatic cancers through targeting vimentin.

How far along are we in revealing the connection between metformin and colorectal cancer?

Colorectal cancer (CRC) is among the most prevalent cancers worldwide, and its prevention and reduction of incidence is imperative. The presence of diabetes has been associated with a 30% increased risk of CRC, likely through the mechanism of hyperinsulinemia, which promotes tumorigenesis via the insulin receptor in the epithelium or by insulin-like growth factor pathways, inflammation, or adipokines, inducing cancer cell proliferation and cancer spread. Metformin, the first-line agent in treating type 2 diabetes, has a chemopreventive role in CRC development. Additionally, preclinical studies suggest synergistic effects of metformin with oxaliplatin in inhibiting in vitro models of colon cancer. Although preclinical studies on the post diagnostic use of metformin were promising and suggested its synergistic effects with chemotherapy, the data on the possible effects of metformin after surgery and other CRC treatment in the clinical setting are less conclusive, and randomized controlled trials are still lacking.

Mechanistic Target of Rapamycin Inhibitors in Renal Cell Carcinoma: Potential, Limitations, and Perspectives.

Several elements highlight the importance of the mechanistic target of rapamycin (mTOR) in the biology of renal cell carcinoma (RCC). mTOR signaling pathway is indeed frequently activated in RCC, inducing cancer cell proliferation and survival. In addition, mTOR promotes tumor angiogenesis and regulates the expression of hypoxia-inducible factors that play an important role in a subset of RCC. Despite mTOR protumorigenic effects, mTOR inhibitors have failed to provide long-lasting anticancer benefits in RCC patients, highlighting the need to readdress their role in the treatment of RCC. This review aims to present the rationale and limitations of targeting mTOR in RCC. Future roles of mTOR inhibitors in the treatment of RCC are also discussed, in particular in the context of immunotherapies.

Role of the mesenchymal stem cells derived from adipose tissue in changing the rate of breast cancer cell proliferation and autophagy, in vitro and in vivo.

Objective(s):Autophagy is an intracellular degradation system of damaged proteins and organelles; however, the role of autophagy in the progression of cancer remains unclear. In recent years, mesenchymal stem cell (MSC)-based approaches have attracted considerable attention for anti-cancer therapy. The present study aimed to examine the interaction of MSCs with the breast cancer cells under autophagy-induced conditions. Materials and Methods:In this study, MSCs isolated from human adipose tissue were co-cultured with MDA-MB 231, a breast cancer cell line, and the autophagy process was induced by tunicamycin treatment. The cell viability was monitored by the MTT assay, and the cells were recovered at different time intervals (24 or 48 hours) to determine autophagy markers such as Beclin, mTOR and the ratio of LC3II/I expression. Additionally, the animal study was conducted using a mouse model of breast cancer treated with isogenic adipose-derived MSCs, and the expression of Beclin and Ki67 was determined using immunohistochemistry in breast tumor tissue.Results:In cancer cells co-cultured with MSCs, the cell proliferation was increased, the Beclin expression and the LC3II/I protein ratio were decreased, and the mTOR expression was increased in MDA-MB 231 upon co-cultured with MSCs. Direct injection of MSCs to a mouse model of breast cancer showed an increase in tumor volume, an increase in the accumulation of Ki67 and a decrease in the Beclin expression in tumor tissues. Conclusion:The data may suggest that suppressed autophagy in breast cancer cells is probably a mechanism by which MSCs can induce cancer cell proliferation.

Clinical development of therapies targeting TGFβ: current knowledge and future perspectives.

Transforming growth factor beta (TGFβ) is a pleiotropic cytokine that plays a key role in both physiologic and pathologic conditions, including cancer. Importantly, TGFβ can exhibit both tumor-suppressive and oncogenic functions. In normal epithelial cells TGFβ acts as an antiproliferative and differentiating factor, whereas in advanced tumors TGFβ can act as an oncogenic factor by creating an immune-suppressive tumor microenvironment, and inducing cancer cell proliferation, angiogenesis, invasion, tumor progression, and metastatic spread. A wealth of preclinical findings have demonstrated that targeting TGFβ is a promising means of exerting antitumor activity. Based on this rationale, several classes of TGFβ inhibitors have been developed and tested in clinical trials, namely, monoclonal, neutralizing, and bifunctional antibodies; antisense oligonucleotides; TGFβ-related vaccines; and receptor kinase inhibitors. It is now >15 years since the first clinical trial testing an anti-TGFβ agent was engaged. Despite the promising preclinical studies, translation of the basic understanding of the TGFβ oncogenic response into the clinical setting has been slow and challenging. Here, we review the conclusions and status of all the completed and ongoing clinical trials that test compounds that inhibit the TGFβ pathway, and discuss the challenges that have arisen during their clinical development. With none of the TGFβ inhibitors evaluated in clinical trials approved for cancer therapy, clinical development for TGFβ blockade therapy is primarily oriented toward TGFβ inhibitor combinations. Immune checkpoint inhibitors are considered candidates, albeit with efficacy anticipated to be restricted to specific populations. In this context, we describe current efforts in the search for biomarkers for selecting the appropriate cancer patients who are likely to benefit from anti-TGFβ therapies. The knowledge accumulated during the last 15 years of clinical research in the context of the TGFβ pathway is crucial to design better, innovative, and more successful trials.

Fibroblast growth factor receptor 4 increases epidermal growth factor receptor (EGFR) signaling by inducing amphiregulin expression and attenuates response to EGFR inhibitors in colon cancer.

Fibroblast growth factor receptor 4 (FGFR4) is known to induce cancer cell proliferation, invasion, and antiapoptosis through activation of RAS/RAF/ERK and PI3K/AKT pathways, which are also known as major molecular bases of colon cancer carcinogenesis related with epidermal growth factor receptor (EGFR) signaling. However, the interaction between FGFR4 and EGFR signaling in regard to colon cancer progression is unclear. Here, we investigated a potential cross‐talk between FGFR4 and EGFR, and the effect of anti‐EGFR therapy in colon cancer treatment. To explore the biological roles of FGFR4 in cancer progression, RNA sequencing was carried out using FGFR4 transfected colon cell lines. Gene ontology data showed the upregulation of genes related to EGFR signaling, and we identified that FGFR4 overexpression secretes EGFR ligands such as amphiregulin (AREG) with consequent activation of EGFR and ErbB3. This result was also shown in in vivo study and the cooperative interaction between EGFR and FGFR4 promoted tumor growth. In addition, FGFR4 overexpression reduced cetuximab‐induced cytotoxicity and the combination of FGFR4 inhibitor (BLU9931) and cetuximab showed profound antitumor effect compared to cetuximab alone. Clinically, we found the positive correlation between FGFR4 and AREG expression in tumor tissue, but not in normal tissue, from colon cancer patients and these expressions were significantly correlated with poor overall survival in patients treated with cetuximab. Therefore, our results provide the novel mechanism of FGFR4 in connection with EGFR activation and the combination of FGFR4 inhibitor and cetuximab could be a promising therapeutic option to achieve the optimal response to anti‐EGFR therapy in colon cancer.

Cancer Cell-derived Secretory Factors in Breast Cancer-associated Lung Metastasis: Their Mechanism and Future Prospects.

In Breast cancer, Lung is the second most common site of metastasis after the bone. Various factors are responsible for Lung metastasis occurring secondary to Breast cancer. Cancer cell-derived secretory factors are commonly known as ‘Cancer Secretomes’. They exhibit a prompt role in the mechanism of Breast cancer lung metastasis. They are also major constituents of host-associated tumor microenvironment. Through cross-talk between cancer cells and the extracellular matrix components, cancer cell-derived extracellular matrix components (CCECs) such as hyaluronan, collagens, laminin and fibronectin cause ECM remodeling at the primary site (breast) of cancer. However, at the secondary site (lung), tenascin C, periostin and lysyl oxidase, along with pro-metastatic molecules Coco and GALNT14, contribute to the formation of pre-metastatic niche (PMN) by promoting ECM remodeling and lung metastatic cells colonization. Cancer cell-derived secretory factors by inducing cancer cell proliferation at the primary site, their invasion through the tissues and vessels and early colonization of metastatic cells in the PMN, potentiate the mechanism of Lung metastasis in Breast cancer.On the basis of biochemical structure, these secretory factors are broadly classified into proteins and non-proteins. This is the first review that has highlighted the role of cancer cell-derived secretory factors in Breast cancer Lung metastasis (BCLM). It also enumerates various researches that have been conducted to date in breast cancer cell lines and animal models that depict the prompt role of various types of cancer cell-derived secretory factors involved in the process of Breast cancer lung metastasis. In the future, by therapeutically targeting these cancer driven molecules, this specific type of organ-tropic metastasis in breast cancer can be successfully treated.

The Oncogenic and Tumor Suppressive Functions of the Long Noncoding RNA MALAT1: An Emerging Controversy.

Long noncoding RNAs are recently emerging as critical factors of tumorigenesis. Originally regarded as a pre-messenger RNA (mRNA) splicing regulator, the long noncoding RNA MALAT1 has been demonstrated to regulate gene transcription by binding histone modification enzymes and transcription factors, and to regulate mRNA and protein expression post-transcriptionally by binding microRNAs (miRNAs) and acting as a sponge. Early studies consistently report that MALAT1 is up-regulated in human cancer tissues of various organ origins, particularly metastatic cancer tissues, that high levels of MALAT1 expression in cancer tissues are associated with poor patient prognosis, and that MALAT1 induces cancer cell proliferation, migration, and invasion in vitro and tumor metastasis in mice. By contrast, by analyzing multiple independent large datasets, MALAT1 have very recently been found to be down-regulated in human colorectal and breast cancer tissues, and low MALAT1 expression is associated with decreased patient survival. By binding to the transcription factor TEAD, MALAT1 suppresses metastasis gene expression, colorectal and breast cancer cell migration, invasion, and metastasis in vitro and in mice. MALAT1 has therefore been proposed to function as a tumor suppressor in colorectal and breast cancers. More comprehensive studies with multiple independent cohorts of human cancer tissues of various organ origins, in vitro and in vivo function, and mechanism studies with rescue experiments are required to confirm the oncogenic or tumor suppressive role of MALAT1 in other cancers.