TGF-β promotes heterogeneity and drug resistance in squamous cell carcinoma

PROX1 induction by autolysosomal activity stabilizes persister-like state of colon cancer via feedback repression of the NOX1-mTORC1 pathway

Cancer chemoresistance is often attributed to slow-cycling persister populations with cancer stem cell (CSC)-like features. However, how persister populations emerge and prevail in cancer remains obscure. We previously demonstrated that while the NOX1-mTORC1 pathway is responsible for proliferation of a fast-cycling CSC population, PROX1 expression is required for chemoresistant persisters in colon cancer. Here, we show that enhanced autolysosomal activity mediated by mTORC1 inhibition induces PROX1 expression and that PROX1 induction in turn inhibits NOX1-mTORC1 activation. CDX2, identified as a transcriptional activator of NOX1, mediates PROX1-dependent NOX1 inhibition. PROX1-positive and CDX2-positive cells are present in distinct populations, and mTOR inhibition triggers conversion of the CDX2-positive population to the PROX1-positive population. Inhibition of autophagy synergizes with mTOR inhibition to block cancer proliferation. Thus, mTORC1 inhibition-mediated induction of PROX1 stabilizes a persister-like state with high autolysosomal activity via a feedback regulation that involves a key cascade of proliferating CSCs.

Repurposing of Chronically Used Drugs in Cancer Therapy: A Chance to Grasp

Despite the advancement in drug discovery for cancer therapy, drug repurposing remains an exceptional opportunistic strategy. This approach offers many advantages (faster, safer, and cheaper drugs) typically needed to overcome increased challenges, i.e., side effects, resistance, and costs associated with cancer therapy. However, not all drug classes suit a patient's condition or long-time use. For that, repurposing chronically used medications is more appealing. This review highlights the importance of repurposing anti-diabetic and anti-hypertensive drugs in the global fight against human malignancies. Extensive searches of all available evidence (up to 30 March 2023) on the anti-cancer activities of anti-diabetic and anti-hypertensive agents are obtained from multiple resources (PubMed, Google Scholar, ClinicalTrials.gov, Drug Bank database, ReDo database, and the National Institutes of Health). Interestingly, more than 92 clinical trials are evaluating the anti-cancer activity of 14 anti-diabetic and anti-hypertensive drugs against more than 15 cancer types. Moreover, some of these agents have reached Phase IV evaluations, suggesting promising official release as anti-cancer medications. This comprehensive review provides current updates on different anti-diabetic and anti-hypertensive classes possessing anti-cancer activities with the available evidence about their mechanism(s) and stage of development and evaluation. Hence, it serves researchers and clinicians interested in anti-cancer drug discovery and cancer management.

Advances in cutaneous squamous cell carcinoma

Human malignancies arise predominantly in tissues of epithelial origin, where the stepwise transformation from healthy epithelium to premalignant dysplasia to invasive neoplasia involves sequential dysregulation of biological networks that govern essential functions of epithelial homeostasis. Cutaneous squamous cell carcinoma (cSCC) is a prototype epithelial malignancy, often with a high tumour mutational burden. A plethora of risk genes, dominated by UV-induced sun damage, drive disease progression in conjunction with stromal interactions and local immunomodulation, enabling continuous tumour growth. Recent studies have identified subpopulations of SCC cells that specifically interact with the tumour microenvironment. These advances, along with increased knowledge of the impact of germline genetics and somatic mutations on cSCC development, have led to a greater appreciation of the complexity of skin cancer pathogenesis and have enabled progress in neoadjuvant immunotherapy, which has improved pathological complete response rates. Although measures for the prevention and therapeutic management of cSCC are associated with clinical benefit, the prognosis remains poor for advanced disease. Elucidating how the genetic mechanisms that drive cSCC interact with the tumour microenvironment is a current focus in efforts to understand, prevent and treat cSCC.

TGF-β mediated drug resistance in solid cancer

Transforming growth factor β (TGF-β) is an important signaling molecule which is expressed in three different isoforms in mammals (i.e. TGF-β1, -β2, and -β3). The interaction between TGF-β and its receptor triggers several pathways, which are classified into SMAD-dependent (canonical) and SMAD-independent (non-canonical) signaling, whose activation/transduction is finely regulated by several mechanisms. TGF-β is involved in many physiological and pathological processes, assuming a dualistic role in cancer progression depending on tumor stage. Indeed, TGF-β inhibits cell proliferation in early-stage tumor cells, while it promotes cancer progression and invasion in advanced tumors, where high levels of TGF-β have been reported in both tumor and stromal cells. In particular, TGF-β signaling has been found to be strongly activated in cancers after treatment with chemotherapeutic agents and radiotherapy, resulting in the onset of drug resistance conditions. In this review we provide an up-to-date description of several mechanisms involved in TGF-β-mediated drug resistance, and we report different strategies that are currently under development in order to target TGF-β pathway and increase tumor sensitivity to therapy.

Prognostic Genomic Markers of Pathological Stage in Oral Squamous Cell Carcinoma

BACKGROUND

To identify the prognostic markers of oral squamous cell carcinoma (OSCC), the genetic heterogeneity of the pathological stages was investigated.

METHODS

The data of 295 patients with primary OSCC obtained from the Cancer Genome Atlas were studied. The genetic prognostic landscape of the pathological stages was systematically analyzed by Cox regressions, Fisher's exact tests, and Gene Ontology (GO) enrichment.

RESULTS

Stage 4 patients had a poor prognosis in univariate and multivariate Cox models. Transforming growth factor-beta (TGF-β) pathway alterations were found more frequently in stage 4, whereas alterations in cell cycle pathways were significant in stages 1, 2, and 3. The differentially mutated genes were divided into three groups: risk genes of high stage, hazardless genes, and risk genes of low stage. The risk genes of low stage (RNF112, AKR7L, ZSCAN5C, and ZPBP) were independent prognostic factors with stage 4 and treatment modality in multivariate Cox regressions. Additionally, in genetic interaction analysis, NOMO1 and ZNF333 had a high co-occurrence in high stage, and WIZ had high co-occurrence in low stage. In GO enrichment, the prognostic genes were clustered at the functional term of RNA polymerase II transcription, and ZNF333 had an association with RNA transcription.

CONCLUSION

The genetic mutation type and ratio of tumor heterogeneity are different for each stage of OSCC, and stratification of OSCC patients with differential therapeutic efficacy is needed. Risk genes of both high and low stages must be identified in patients diagnosed with low-stage OSCC. Mutations in NOMO1, ZNF333, and WIZ should be considered as potential prognostic markers.

Volume imaging to interrogate cancer cell-tumor microenvironment interactions in space and time

Volume imaging visualizes the three-dimensional (3D) complexity of tumors to unravel the dynamic crosstalk between cancer cells and the heterogeneous landscape of the tumor microenvironment (TME). Tissue clearing and intravital microscopy (IVM) constitute rapidly progressing technologies to study the architectural context of such interactions. Tissue clearing enables high-resolution imaging of large samples, allowing for the characterization of entire tumors and even organs and organisms with tumors. With IVM, the dynamic engagement between cancer cells and the TME can be visualized in 3D over time, allowing for acquisition of 4D data. Together, tissue clearing and IVM have been critical in the examination of cancer-TME interactions and have drastically advanced our knowledge in fundamental cancer research and clinical oncology. This review provides an overview of the current technical repertoire of fluorescence volume imaging technologies to study cancer and the TME, and discusses how their recent applications have been utilized to advance our fundamental understanding of tumor architecture, stromal and immune infiltration, vascularization and innervation, and to explore avenues for immunotherapy and optimized chemotherapy delivery.

First-in-human study of E7130 (a tumor microenvironment-ameliorating microtubule inhibitor) in patients with advanced solid tumors: Primary results of the dose-escalation part

BACKGROUND

E7130 is a novel anticancer agent created from a total synthetic study of norhalichondrin B. The authors report the E7130 dose-escalation part of a first-in-human study of patients with advanced solid tumors (NCT03444701).

METHODS

Japanese patients ≥20 years of age were enrolled. E7130 was administered intravenously in two cycles: day 1 of a 21-day cycle (Q3W) or days 1 and 15 of a 28-day cycle (Q2W). Doses were escalated from 270 to 550 μg/m² for the Q3W group or 25-400 μg/m² for the Q2W group. The primary end point of the dose-escalation phase was safety and tolerability as assessed by the incidence of dose-limiting toxicities (DLTs) and adverse events. Other end points included determination of the maximum tolerated dose (MTD), pharmacokinetics, and pharmacodynamics.

RESULTS

Forty-four patients were enrolled: 15 in the E7130 Q3W group and 29 in the Q2W group. Treatment-emergent adverse events (TEAEs) occurred in all patients; the most common TEAE overall was leukopenia (78.6%). Grade 3-4 TEAEs occurred in 93.3% of patients in the Q3W group and 86.2% of patients in the Q2W group. None had a TEAE resulting in study drug discontinuation, and no treatment-related deaths were reported. Per the DLT evaluation, the MTDs were determined as 480 μg/m² Q3W and 300 μg/m² Q2W. Significant changes in multiple plasma biomarkers, including vascular endothelial growth factor 3 and matrix metallopeptidase 9, were dose-dependent after initial doses of 350-480 μg/m² .

CONCLUSIONS

E7130 480 μg/m² Q3W was chosen for the dose-expansion part over 300 μg/m² Q2W primarily per dose-dependent biomarker results.

STING inhibits the reactivation of dormant metastasis in lung adenocarcinoma

Metastasis frequently develops from disseminated cancer cells that remain dormant after the apparently successful treatment of a primary tumour. These cells fluctuate between an immune-evasive quiescent state and a proliferative state liable to immune-mediated elimination1-6. Little is known about the clearing of reawakened metastatic cells and how this process could be therapeutically activated to eliminate residual disease in patients. Here we use models of indolent lung adenocarcinoma metastasis to identify cancer cell-intrinsic determinants of immune reactivity during exit from dormancy. Genetic screens of tumour-intrinsic immune regulators identified the stimulator of interferon genes (STING) pathway as a suppressor of metastatic outbreak. STING activity increases in metastatic progenitors that re-enter the cell cycle and is dampened by hypermethylation of the STING promoter and enhancer in breakthrough metastases or by chromatin repression in cells re-entering dormancy in response to TGFβ. STING expression in cancer cells derived from spontaneous metastases suppresses their outgrowth. Systemic treatment of mice with STING agonists eliminates dormant metastasis and prevents spontaneous outbreaks in a T cell- and natural killer cell-dependent manner-these effects require cancer cell STING function. Thus, STING provides a checkpoint against the progression of dormant metastasis and a therapeutically actionable strategy for the prevention of disease relapse.

CTHRC1 is associated with immune cell infiltration and functions as an adverse marker for prognosis in head and neck squamous cell carcinoma

Collagen triple helix repeat containing 1 (CTHRC1) is a secreted glycoprotein that decreases the deposition of collagen matrix and accelerates tumor metastasis. However, the relationship between CTHRC1 and the outcomes of head and neck squamous cell carcinoma (HNSCC) and tumor-infiltrating lymphocytes remains unclear. In the present study, the transcriptional level of CTHRC1 and its association with overall survival (OS) and relapse-free survival (RFS) time in diverse cancer types were evaluated using The Cancer Genome Atlas, Tumor Immune Estimation Resource (TIMER), ONCOMINE and Kaplan-Meier plotter databases. The association of CTHRC1 expression level with the clinicopathological parameters of patients with HNSCC from The University of ALabama at Birmingham CANcer data analysis Portal (UALCAN) database were also evaluated. Enrichment analysis of CTHRC1 was carried out using gene set enrichment analysis software. CIBERSORT and TIMER databases were used to evaluate the relationship between the expression level of CTHRC1 and the proportion of tumor-infiltrating immune cells (TICs) in multiple cancer types. Moreover, immunohistochemistry was used to verify the expression of CTHRC1 in clinical samples of HNSCC. CTHRC1 was upregulated in HNSCC and high expression of CTHRC1 was associated with worsening clinicopathologic parameters and shorter OS and RFS times. There were eight HALLMARK gene sets, 1,231 immune signature gene sets and 14 KEGG gene sets significantly enriched in the high CTHRC1 expression group, while no gene set was enriched in the low CTHRC1 expression group. The expression of CTHRC1 was closely correlated with the proportion of TICs, where the expression of CTHRC1 was significantly positively correlated with the amount of infiltrated M0 and M2 macrophages, and significantly negatively associated with the levels of M1 macrophages. These findings suggest that CTHRC1 is an adverse prognostic marker and is associated with immune cell infiltration in HNSCC.

Emerging Role of NRF2 Signaling in Cancer Stem Cell Phenotype

Cancer stem cells (CSCs) are a small population of tumor cells characterized by self-renewal and differentiation capacity. CSCs are currently postulated as the driving force that induces intra-tumor heterogeneity leading to tumor initiation, metastasis, and eventually tumor relapse. Notably, CSCs are inherently resistant to environmental stress, chemotherapy, and radiotherapy due to high levels of antioxidant systems and drug efflux transporters. In this context, a therapeutic strategy targeting the CSC-specific pathway holds a promising cure for cancer. NRF2 (nuclear factor erythroid 2-like 2; NFE2L2) is a master transcription factor that regulates an array of genes involved in the detoxification of reactive oxygen species/electrophiles. Accumulating evidence suggests that persistent NRF2 activation, observed in multiple types of cancer, supports tumor growth, aggressive malignancy, and therapy resistance. Herein, we describe the core properties of CSCs, focusing on treatment resistance, and review the evidence that demonstrates the roles of NRF2 signaling in conferring unique properties of CSCs and the associated signaling pathways.

TGF-β signaling pathway: Therapeutic targeting and potential for anti-cancer immunity

Transforming growth factor-β (TGFβ) is a pleiotropic secretory cytokine exhibiting both cancer-inhibitory and promoting properties. It transmits its signals via Suppressor of Mother against Decapentaplegic (SMAD) and non-SMAD pathways and regulates cell proliferation, differentiation, invasion, migration, and apoptosis. In non-cancer and early-stage cancer cells, TGFβ signaling suppresses cancer progression via inducing apoptosis, cell cycle arrest, or anti-proliferation, and promoting cell differentiation. On the other hand, TGFβ may also act as an oncogene in advanced stages of tumors, wherein it develops immune-suppressive tumor microenvironments and induces the proliferation of cancer cells, invasion, angiogenesis, tumorigenesis, and metastasis. Higher TGFβ expression leads to the instigation and development of cancer. Therefore, suppressing TGFβ signals may present a potential treatment option for inhibiting tumorigenesis and metastasis. Different inhibitory molecules, including ligand traps, anti-sense oligo-nucleotides, small molecule receptor-kinase inhibitors, small molecule inhibitors, and vaccines, have been developed and clinically trialed for blocking the TGFβ signaling pathway. These molecules are not pro-oncogenic response-specific but block all signaling effects induced by TGFβ. Nonetheless, targeting the activation of TGFβ signaling with maximized specificity and minimized toxicity can enhance the efficacy of therapeutic approaches against this signaling pathway. The molecules that are used to target TGFβ are non-cytotoxic to cancer cells but designed to curtail the over-activation of invasion and metastasis driving TGFβ signaling in stromal and cancer cells. Here, we discussed the critical role of TGFβ in tumorigenesis, and metastasis, as well as the outcome and the promising achievement of TGFβ inhibitory molecules in the treatment of cancer.

Intersection of immune and oncometabolic pathways drives cancer hyperprogression during immunotherapy

Immune checkpoint blockade (ICB) can produce durable responses against cancer. We and others have found that a subset of patients experiences paradoxical rapid cancer progression during immunotherapy. It is poorly understood how tumors can accelerate their progression during ICB. In some preclinical models, ICB causes hyperprogressive disease (HPD). While immune exclusion drives resistance to ICB, counterintuitively, patients with HPD and complete response (CR) following ICB manifest comparable levels of tumor-infiltrating CD8+ T cells and interferon γ (IFNγ) gene signature. Interestingly, patients with HPD but not CR exhibit elevated tumoral fibroblast growth factor 2 (FGF2) and β-catenin signaling. In animal models, T cell-derived IFNγ promotes tumor FGF2 signaling, thereby suppressing PKM2 activity and decreasing NAD+, resulting in reduction of SIRT1-mediated β-catenin deacetylation and enhanced β-catenin acetylation, consequently reprograming tumor stemness. Targeting the IFNγ-PKM2-β-catenin axis prevents HPD in preclinical models. Thus, the crosstalk of core immunogenic, metabolic, and oncogenic pathways via the IFNγ-PKM2-β-catenin cascade underlies ICB-associated HPD.

Cancer stem cell-derived extracellular vesicles preferentially target MHC-II-macrophages and PD1+ T cells in the tumor microenvironment

Immunotherapy is an approved treatment option for head and neck squamous cell carcinoma (HNSCC). However, the response rate to immune checkpoint blockade is only 13% for recurrent HNSCC, highlighting the urgent need to better understand tumor-immune interplay, with the ultimate goal of improving patient outcomes. HNSCC present high local recurrence rates and therapy resistance that can be attributed to the presence of cancer stem cells (CSC) within tumors. CSC exhibit singular properties that enable them to avoid immune detection and eradication. How CSC communicate with immune cells and which immune cell types are preferentially found within the CSC niche are still open questions. Here, we used genetic approaches to specifically label CSC-derived extracellular vesicles (EVs) and to perform Sortase-mediated in vivo proximity labeling of CSC niche cells. We identified specific immune cell subsets that were selectively targeted by EVCSC and that were found in the CSC niche. Native EVCSC preferentially targeted MHC-II-macrophages and PD1+ T cells in the tumor microenvironment, which were the same immune cell subsets enriched within the CSC niche. These observations indicate that the use of genetic technologies able to track EVs without in vitro isolation are a valuable tool to unveil the biology of native EVCSC.

Subclonal evolution and expansion of spatially distinct THY1-positive cells is associated with recurrence in glioblastoma

PURPOSE

Glioblastoma(GBM) is a lethal disease characterized by inevitable recurrence. Here we investigate the molecular pathways mediating resistance, with the goal of identifying novel therapeutic opportunities.

EXPERIMENTAL DESIGN

We developed a longitudinal in vivo recurrence model utilizing patient-derived explants to produce paired specimens(pre- and post-recurrence) following temozolomide(TMZ) and radiation(IR). These specimens were evaluated for treatment response and to identify gene expression pathways driving treatment resistance. Findings were clinically validated using spatial transcriptomics of human GBMs.

RESULTS

These studies reveal in replicate cohorts, a gene expression profile characterized by upregulation of mesenchymal and stem-like genes at recurrence. Analyses of clinical databases revealed significant association of this transcriptional profile with worse overall survival and upregulation at recurrence. Notably, gene expression analyses identified upregulation of TGFβ signaling, and more than one-hundred-fold increase in THY1 levels at recurrence. Furthermore, THY1-positive cells represented <10% of cells in treatment-naïve tumors, compared to 75-96% in recurrent tumors. We then isolated THY1-positive cells from treatment-naïve patient samples and determined that they were inherently resistant to chemoradiation in orthotopic models. Additionally, using image-guided biopsies from treatment-naïve human GBM, we conducted spatial transcriptomic analyses. This revealed rare THY1+ regions characterized by mesenchymal/stem-like gene expression, analogous to our recurrent mouse model, which co-localized with macrophages within the perivascular niche. We then inhibited TGFBRI activity in vivo which decreased mesenchymal/stem-like protein levels, including THY1, and restored sensitivity to TMZ/IR in recurrent tumors.

CONCLUSIONS

These findings reveal that GBM recurrence may result from tumor repopulation by pre-existing, therapy-resistant, THY1-positive, mesenchymal cells within the perivascular niche.

Targeting cancer drug resistance utilizing organoid technology

Cancer organoids generated from 3D in vitro cell cultures have contributed to the study of drug resistance. Maintenance of genomic and transcriptomic similarity between organoids and parental cancer allows organoids to have the ability of accurate prediction in drug resistance testing. Protocols of establishing therapy-sensitive and therapy-resistant organoids are concluded in two aspects, which are generated directly from respective patients' cancer and by induction of anti-cancer drug. Genomic and transcriptomic analyses and gene editing have been applied to organoid studies to identify key targets in drug resistance and FGFR3, KHDRBS3, lnc-RP11-536 K7.3 and FBN1 were found to be key targets. Furthermore, mechanisms contributing to resistance have been identified, including metabolic adaptation, activation of DNA damage response, defects in apoptosis, reduced cellular senescence, cellular plasticity, subpopulation interactions and gene fusions. Additionally, cancer stem cells (CSCs) have been verified to be involved in drug resistance utilizing organoid technology. Reversal of drug resistance can be achieved by targeting key genes and CSCs in cancer organoids. In this review, we summarize applications of organoids to cancer drug resistance research, indicating prospects and limitations.

Re-Sensitizing Cancer Stem Cells to Conventional Chemotherapy Agents

Cancer stem cells are found in many cancer types. They comprise a distinct subpopulation of cells within the tumor that exhibit properties of stem cells. They express a number of cell surface markers, such as CD133, CD44, ALDH, and EpCAM, as well as embryonic transcription factors Oct4, Nanog, and SOX2. CSCs are more resistant to conventional chemotherapy and can potentially drive tumor relapse. Therefore, it is essential to understand the molecular mechanisms that drive chemoresistance and to target them with specific therapy effectively. Highly conserved developmental signaling pathways such as Wnt, Hedgehog, and Notch are commonly reported to play a role in CSCs chemoresistance development. Studies show that particular pathway inhibitors combined with conventional therapy may re-establish sensitivity to the conventional therapy. Another significant contributor of chemoresistance is a specific tumor microenvironment. Surrounding stroma in the form of cancer-associated fibroblasts, macrophages, endothelial cells, and extracellular matrix components produce cytokines and other factors, thus creating a favorable environment and decreasing the cytotoxic effects of chemotherapy. Anti-stromal agents may potentially help to overcome these effects. Epigenetic changes and autophagy were also among the commonly reported mechanisms of chemoresistance. This review provides an overview of signaling pathway components involved in the development of chemoresistance of CSCs and gathers evidence from experimental studies in which CSCs can be re-sensitized to conventional chemotherapy agents across different cancer types.

Exploration of the Use of Natural Compounds in Combination with Chemotherapy Drugs for Tumor Treatment

Currently, chemotherapy is the main treatment for tumors, but there are still problems such as unsatisfactory chemotherapy results, susceptibility to drug resistance, and serious adverse effects. Natural compounds have numerous pharmacological activities which are important sources of drug discovery for tumor treatment. The combination of chemotherapeutic drugs and natural compounds is gradually becoming an important strategy and development direction for tumor treatment. In this paper, we described the role of natural compounds in combination with chemotherapeutic drugs in synergizing, reducing drug resistance, mitigating adverse effects and related mechanisms, and providing new insights for future oncology research.

The epigenome and the many facets of cancer drug tolerance

The use of chemotherapeutic agents and the development of new cancer therapies over the past few decades has consequently led to the emergence of myriad therapeutic resistance mechanisms. Once thought to be explicitly driven by genetics, the coupling of reversible sensitivity and absence of pre-existing mutations in some tumors opened the way for discovery of drug-tolerant persisters (DTPs): slow-cycling subpopulations of tumor cells that exhibit reversible sensitivity to therapy. These cells confer multi-drug tolerance, to targeted and chemotherapies alike, until the residual disease can establish a stable, drug-resistant state. The DTP state can exploit a multitude of distinct, yet interlaced, mechanisms to survive otherwise lethal drug exposures. Here, we categorize these multi-faceted defense mechanisms into unique Hallmarks of Cancer Drug Tolerance. At the highest level, these are comprised of heterogeneity, signaling plasticity, differentiation, proliferation/metabolism, stress management, genomic integrity, crosstalk with the tumor microenvironment, immune escape, and epigenetic regulatory mechanisms. Of these, epigenetics was both one of the first proposed means of non-genetic resistance and one of the first discovered. As we describe in this review, epigenetic regulatory factors are involved in most facets of DTP biology, positioning this hallmark as an overarching mediator of drug tolerance and a potential avenue to novel therapies.

Transforming growth factor-β signaling: from tumor microenvironment to anticancer therapy

Transforming growth factor-β (TGF-β) signaling is an important pathway for promoting the pathogenesis of inflammatory diseases, including cancer. The roles of TGF-β signaling are heterogeneous and versatile in cancer development and progression, both anticancer and protumoral actions are reported. Interestingly, increasing evidence suggests that TGF-β enhances disease progression and drug resistance via immune-modulatory actions in the tumor microenvironment (TME) of solid tumors. A better understanding of its regulatory mechanisms in the TME at the molecular level can facilitate the development of precision medicine to block the protumoral actions of TGF-β in the TME. Here, the latest information about the regulatory mechanisms and translational research of TGF-β signaling in the TME for therapeutic development had been summarized.

Deciphering functional tumor states at single-cell resolution

Within a tumor, cancer cells exist in different states that are associated with distinct tumor functions, including proliferation, differentiation, invasion, metastasis, and resistance to anti-cancer therapy. The identification of the gene regulatory networks underpinning each state is essential for better understanding functional tumor heterogeneity and revealing tumor vulnerabilities. Here, we review the different studies identifying tumor states by single-cell sequencing approaches and the mechanisms that promote and sustain these functional states and regulate their transitions. We also describe how different tumor states are spatially distributed and interact with the specific stromal cells that compose the tumor microenvironment. Finally, we discuss how the understanding of tumor plasticity and transition states can be used to develop new strategies to improve cancer therapy.

Three-dimensional Imaging Reveals Immune-driven Tumor-associated High Endothelial Venules as a Key Correlate of Tumor Rejection Following Depletion of Regulatory T Cells

High endothelial venules (HEV) are specialized post capillary venules that recruit naïve T cells and B cells into secondary lymphoid organs (SLO) such as lymph nodes (LN). Expansion of HEV networks in SLOs occurs following immune activation to support development of an effective immune response. In this study, we used a carcinogen-induced model of fibrosarcoma to examine HEV remodeling after depletion of regulatory T cells (Treg). We used light sheet fluorescence microscopy imaging to visualize entire HEV networks, subsequently applying computational tools to enable topological mapping and extraction of numerical descriptors of the networks. While these analyses revealed profound cancer- and immune-driven alterations to HEV networks within LNs, these changes did not identify successful responses to treatment. The presence of HEV networks within tumors did however clearly distinguish responders from nonresponders. Finally, we show that a successful treatment response is dependent on coupling tumor-associated HEV (TA-HEV) development to T-cell activation implying that T-cell activation acts as the trigger for development of TA-HEVs which subsequently serve to amplify the immune response by facilitating extravasation of T cells into the tumor mass.

Ras drives malignancy through stem cell crosstalk with the microenvironment

Squamous cell carcinomas are triggered by marked elevation of RAS-MAPK signalling and progression from benign papilloma to invasive malignancy1-4. At tumour-stromal interfaces, a subset of tumour-initiating progenitors, the cancer stem cells, obtain increased resistance to chemotherapy and immunotherapy along this pathway5,6. The distribution and changes in cancer stem cells during progression from a benign state to invasive squamous cell carcinoma remain unclear. Here we show in mice that, after oncogenic RAS activation, cancer stem cells rewire their gene expression program and trigger self-propelling, aberrant signalling crosstalk with their tissue microenvironment that drives their malignant progression. The non-genetic, dynamic cascade of intercellular exchanges involves downstream pathways that are often mutated in advanced metastatic squamous cell carcinomas with high mutational burden7. Coupling our clonal skin HRASG12V mouse model with single-cell transcriptomics, chromatin landscaping, lentiviral reporters and lineage tracing, we show that aberrant crosstalk between cancer stem cells and their microenvironment triggers angiogenesis and TGFβ signalling, creating conditions that are conducive for hijacking leptin and leptin receptor signalling, which in turn launches downstream phosphoinositide 3-kinase (PI3K)-AKT-mTOR signalling during the benign-to-malignant transition. By functionally examining each step in this pathway, we reveal how dynamic temporal crosstalk with the microenvironment orchestrated by the stem cells profoundly fuels this path to malignancy. These insights suggest broad implications for cancer therapeutics.

Targeting oncogenic transcription factors in skin malignancies: An update on cancer stemness and therapeutic outcomes

The skin is the largest organ of the human body and prone to various diseases, including cancer; thus, provides the first line of defense against exogenous biological and non-biological agents. Skin cancer, a complex and heterogenic process, with steep incidence rate often metastasizes due to poor understanding of the underlying mechanisms of pathogenesis and clinical challenges. Indeed, accumulating evidence indicates that deregulation of transcription factors (TFs) due to genetic, epigenetic and signaling distortions plays essential role in the development of cutaneous malignancies and therapeutic challenges including cancer stemness features and reprogramming. This review highlights the recent developments exploring underlying mechanisms how deregulated TFs (e.g., NF-κB, AP-1, STAT etc.,) orchestrates cutaneous onco-pathogenesis, reprogramming, stemness and poor clinical outcomes. Along this line, bioactive drugs, and their derivatives from natural and or synthetic origin has gained attention due to their multitargeting potential, potentially safer and effective therapeutic outcome for human malignancies. We also discussed therapeutic importance of targeting aberrantly expressed TFs in skin cancers with bioactive natural products and or synthetic agents.

Chemokines and cytokines: Axis and allies in prostate cancer pathogenesis

Chemokines are recognized as the major contributor to various tumorigenesis, tumor heterogeneity, and failures of current cancer therapies. The tumor microenvironment (TME) is enriched with chemokines and cytokines and plays a pivotal role in cancer progression. Chronic inflammation is also considered an instructive process of cancer progression, where chemokines are spatiotemporally secreted by malignant cells and leukocyte subtypes that initiate cell trafficking into the TME. In various cancers, prostate cancer (PCa) is reported as one of the leading cancers in the worldwide male population. The chemokines-mediated signaling pathways are intensively involved in PCa progression and metastasis. Emerging evidence suggests that chemokines and cytokines are responsible for the pleiotropic actions in cancer, including the growth, angiogenesis, endothelial mesenchymal transition, leukocyte infiltration, and hormone escape for advanced PCa and therapy resistance. Chemokine's system and immune cells represent a promising target to suppress tumorigenic environments and serve as potential therapy/immunotherapy for the PCa. In this review, an attempt has been made to shed light on the alteration of chemokine and cytokine profiles during PCa progression and metastasis. We also discussed the recent findings of the diverse molecular signaling of these circulating chemokines and their corresponding receptors that could become future targets for therapeutic management of PCa.

TGF-β in Developmental and Fibrogenic EMTs

TGF-β plays a prominent role as an inducer of epithelial-mesenchymal transitions (EMTs) during development and wound healing and in disease conditions such as fibrosis and cancer. During these processes EMT occurs together with changes in cell proliferation, differentiation, communication, and extracellular matrix remodeling that are orchestrated by multiple signaling inputs besides TGF-β. Chief among these inputs is RAS-MAPK signaling, which is frequently required for EMT induction by TGF-β. Recent work elucidated the molecular basis for the cooperation between the TGF-β-SMAD and RAS-MAPK pathways in the induction of EMT in embryonic, adult and carcinoma epithelial cells. These studies also provided direct mechanistic links between EMT and progenitor cell differentiation during gastrulation or intra-tumoral fibrosis during cancer metastasis. These insights illuminate the nature of TGF-β driven EMTs as part of broader processes during development, fibrogenesis and metastasis.

Epithelial-mesenchymal transition in cancer stemness and heterogeneity: updated

Epithelial-mesenchymal transition (EMT) as a trans-differentiation program and a key process in tumor progression is linked positively with increased expansion of cancer stem cells and cells with stem-like properties. This is mediated through modulation of critical tumorigenic events and is positively correlated with hypoxic conditions in tumor microenvironment. The presence of cells eliciting diverse phenotypical states inside tumor is representative of heterogeneity and higher tumor resistance to therapy. In this review, we aimed to discuss about the current understanding toward EMT, stemness, and heterogeneity in tumors of solid organs, their contribution to the key tumorigenic events along with major signaling pathway involved, and, finally, to suggest some strategies to target these critical events.

Integrated Machine Learning and Single-Sample Gene Set Enrichment Analysis Identifies a TGF-Beta Signaling Pathway Derived Score in Headneck Squamous Cell Carcinoma

Background

The TGF-β signaling pathway is clinically predictive of pan-cancer. Nevertheless, its clinical prognosis and regulation of immune microenvironment (TME) characteristics as well as the prediction of immunotherapy efficacy need to be further elucidated in head and neck squamous cell carcinoma.

Method

At first, we summarized TGF-β related genes from previous published articles, used ssGSEA to establish the TGF-β risk score. Considering the complexity of its clinical application, we improved it with the LASSO-COX algorithm to construct the model. In addition, we explored the predictive efficacy of TGF-β risk score in the observation of TME phenotype and immunotherapy effect. Finally, the potency of TGF-β risk score in adjusting precise treatment of HNSC was evaluated.

Results

We systematically established TGF-β risk score with multi-level predictive ability. TGF-β risk score was employed to predict the tumor microenvironment status, which was negatively associated with NK cells but positively related to macrophages and fibroblasts. It reveals that patients with high TGF-β risk score predict “cold” TME status. In addition, higher risk scores indicate higher sensitivity to immunotherapy.

Conclusion

We first construct and validate TGF-β characteristics that can predict immune microenvironment phenotypes and immunotherapeutic effect in multiple datasets. Noteworthy, TGF-β risk score is helpful for individualized precise treatment of patients with the head and neck squamous cell carcinoma.

Regulation of temozolomide resistance via lncRNAs: Clinical and biological properties of lncRNAs in gliomas (Review)

Gliomas are a primary types of intracranial malignancies and are characterized by a poor prognosis due to aggressive recurrence profiles. Temozolomide (TMZ) is an auxiliary alkylating agent that is extensively used in conjunction with surgical resection and forms the mainstay of clinical treatment strategies for gliomas. However, the frequent occurrence of TMZ resistance in clinical practice limits its therapeutic efficacy. Accumulating evidence has demonstrated that long non‑coding RNAs (lncRNAs) can play key and varied roles in glioma progression. lncRNAs have been reported to inhibit glioma progression by targeting various signaling pathways. In addition, the differential expression of lncRNAs has also been found to mediate the resistance of glioma to several chemotherapeutic agents, particularly to TMZ. The present review article therefore summarizes the findings of previous studies in an aim to report the significance and function of lncRNAs in regulating the chemoresistance of gliomas. The present review may provide further insight into the clinical treatment of gliomas.

Deconvolution of tumor composition using partially available DNA methylation data

Background

Deciphering proportions of constitutional cell types in tumor tissues is a crucial step for the analysis of tumor heterogeneity and the prediction of response to immunotherapy. In the process of measuring cell population proportions, traditional experimental methods have been greatly hampered by the cost and extensive dropout events. At present, the public availability of large amounts of DNA methylation data makes it possible to use computational methods to predict proportions.

Results

In this paper, we proposed PRMeth, a method to deconvolve tumor mixtures using partially available DNA methylation data. By adopting an iteratively optimized non-negative matrix factorization framework, PRMeth took DNA methylation profiles of a portion of the cell types in the tissue mixtures (including blood and solid tumors) as input to estimate the proportions of all cell types as well as the methylation profiles of unknown cell types simultaneously. We compared PRMeth with five different methods through three benchmark datasets and the results show that PRMeth could infer the proportions of all cell types and recover the methylation profiles of unknown cell types effectively. Then, applying PRMeth to four types of tumors from The Cancer Genome Atlas (TCGA) database, we found that the immune cell proportions estimated by PRMeth were largely consistent with previous studies and met biological significance.

Conclusions

Our method can circumvent the difficulty of obtaining complete DNA methylation reference data and obtain satisfactory deconvolution accuracy, which will be conducive to exploring the new directions of cancer immunotherapy. PRMeth is implemented in R and is freely available from GitHub (https://github.com/hedingqin/PRMeth).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12859-022-04893-7.

The Extracellular Matrix: A Key Accomplice of Cancer Stem Cell Migration, Metastasis Formation, and Drug Resistance in PDAC

Pancreatic ductal adenocarcinoma (PDAC) is rich in dense fibrotic stroma that are composed of extracellular matrix (ECM) proteins. A disruption of the balance between ECM synthesis and secretion and the altered expression of matrix remodeling enzymes lead to abnormal ECM dynamics in PDAC. This pathological ECM promotes cancer growth, survival, invasion, and alters the behavior of fibroblasts and immune cells leading to metastasis formation and chemotherapy resistance, which contribute to the high lethality of PDAC. Additionally, recent evidence highlights that ECM, as a major structural component of the tumor microenvironment, is a highly dynamic structure in which ECM proteins establish a physical and biochemical niche for cancer stem cells (CSCs). CSCs are characterized by self-renewal, tumor initiation, and resistance to chemotherapeutics. In this review, we will discuss the effects of the ECM on tumor biological behavior and its molecular impact on the fundamental signaling pathways in PDAC. We will also provide an overview of how the different ECM components are able to modulate CSCs properties and finally discuss the current and ongoing therapeutic strategies targeting the ECM. Given the many challenges facing current targeted therapies for PDAC, a better understanding of molecular events involving the interplay of ECM and CSC will be key in identifying more effective therapeutic strategies to eliminate CSCs and ultimately to improve survival in patients that are suffering from this deadly disease.

Engaging plasticity: Differentiation therapy in solid tumors

Cancer is a systemic heterogeneous disease that can undergo several rounds of latency and activation. Tumor progression evolves by increasing diversity, adaptation to signals from the microenvironment and escape mechanisms from therapy. These dynamic processes indicate necessity for cell plasticity. Epithelial-mesenchymal transition (EMT) plays a major role in facilitating cell plasticity in solid tumors by inducing dedifferentiation and cell type transitions. These two practices, plasticity and dedifferentiation enhance tumor heterogeneity creating a key challenge in cancer treatment. In this review we will explore cancer cell plasticity and elaborate treatment modalities that aspire to overcome such dynamic processes in solid tumors. We will further discuss the therapeutic potential of utilizing enhanced cell plasticity for differentiation therapy.

LncRNA-Dependent Mechanisms of Transforming Growth Factor-β: From Tissue Fibrosis to Cancer Progression

Transforming growth factor-β (TGF-β) is a crucial pathogenic mediator of inflammatory diseases. In tissue fibrosis, TGF-β regulates the pathogenic activity of infiltrated immunocytes and promotes extracellular matrix production via de novo myofibroblast generation and kidney cell activation. In cancer, TGF-β promotes cancer invasion and metastasis by enhancing the stemness and epithelial mesenchymal transition of cancer cells. However, TGF-β is highly pleiotropic in both tissue fibrosis and cancers, and thus, direct targeting of TGF-β may also block its protective anti-inflammatory and tumor-suppressive effects, resulting in undesirable outcomes. Increasing evidence suggests the involvement of long non-coding RNAs (lncRNAs) in TGF-β-driven tissue fibrosis and cancer progression with a high cell-type and disease specificity, serving as an ideal target for therapeutic development. In this review, the mechanism and translational potential of TGF-β-associated lncRNAs in tissue fibrosis and cancer will be discussed.

Dynamic Visualization of TGF-β/SMAD3 Transcriptional Responses in Single Living Cells

Simple Summary

How a single cytokine can induce a variety of cellular responses in the same cell or in different cells is a longstanding question. Transforming growth factor β (TGF-β) is a prototypical multifunctional cytokine of which biological responses are highly dependent on in a cellular context. TGF-β signals via intracellular SMAD transcription factors, and the duration and intensity of SMAD activation are key determinants for the responses that are elicited by TGF-β. To visualize the TGF-β signaling kinetics, we developed a dynamic TGF-β/SMAD3 transcriptional reporter using a quickly folded and highly unstable green florescent protein. We demonstrate the specificity and sensitivity of this reporter and its wide application to monitor dynamic TGF-β-induced responses in cells cultured on plastic dishes, and in living animals. This tool allows for the analysis of TGF-β signaling at a single living cell level, and allows for the discovery of dynamic TGF-β SMAD- induced transcriptional responses in multi-step biological processes.

Abstract

Transforming growth factor-β (TGF-β) signaling is tightly controlled in duration and intensity during embryonic development and in the adult to maintain tissue homeostasis. To visualize the TGF-β/SMAD3 signaling kinetics, we developed a dynamic TGF-β/SMAD3 transcriptional fluorescent reporter using multimerized SMAD3/4 binding elements driving the expression of a quickly folded and highly unstable GFP protein. We demonstrate the specificity and sensitivity of this reporter and its wide application to monitor dynamic TGF-β/SMAD3 transcriptional responses in both 2D and 3D systems in vitro, as well as in vivo, using live-cell and intravital imaging. Using this reporter in B16F10 cells, we observed single cell heterogeneity in response to TGF-β challenge, which can be categorized into early, late, and non-responders. Because of its broad application potential, this reporter allows for new discoveries into how TGF-β/SMAD3-dependent transcriptional dynamics are affected during multistep and reversible biological processes.

High-Resolution 3D Heart Models of Cardiomyocyte Subpopulations in Cleared Murine Heart

Biological tissues are naturally three-dimensional (3D) opaque structures, which poses a major challenge for the deep imaging of spatial distribution and localization of specific cell types in organs in biomedical research. Here we present a 3D heart imaging reconstruction approach by combining an improved heart tissue-clearing technique with high-resolution light-sheet fluorescence microscopy (LSFM). We have conducted a three-dimensional and multi-scale volumetric imaging of the ultra-thin planes of murine hearts for up to 2,000 images per heart in x-, y-, and z three directions. High-resolution 3D volume heart models were constructed in real-time by the Zeiss Zen program. By using such an approach, we investigated detailed three-dimensional spatial distributions of two specific cardiomyocyte populations including HCN4 expressing pacemaker cells and Pnmt+ cell-derived cardiomyocytes by using reporter mouse lines Hcn4DreER/tdTomato and PnmtCre/ChR2-tdTomato. HCN4 is distributed throughout right atrial nodal regions (i.e., sinoatrial and atrioventricular nodes) and the superior-inferior vena cava axis, while Pnmt+ cell-derived cardiomyocytes show distinct ventral, left heart, and dorsal side distribution pattern. Our further electrophysiological analysis indicates that Pnmt + cell-derived cardiomyocytes rich left ventricular (LV) base is more susceptible to ventricular arrhythmia under adrenergic stress than left ventricular apex or right ventricle regions. Thus, our 3D heart imaging reconstruction approach provides a new solution for studying the geometrical, topological, and physiological characteristics of specific cell types in organs.

3D imaging for driving cancer discovery

Our understanding of the cellular composition and architecture of cancer has primarily advanced using 2D models and thin slice samples. This has granted spatial information on fundamental cancer biology and treatment response. However, tissues contain a variety of interconnected cells with different functional states and shapes, and this complex organization is impossible to capture in a single plane. Furthermore, tumours have been shown to be highly heterogenous, requiring large-scale spatial analysis to reliably profile their cellular and structural composition. Volumetric imaging permits the visualization of intact biological samples, thereby revealing the spatio-phenotypic and dynamic traits of cancer. This review focuses on new insights into cancer biology uniquely brought to light by 3D imaging and concomitant progress in cancer modelling and quantitative analysis. 3D imaging has the potential to generate broad knowledge advance from major mechanisms of tumour progression to new strategies for cancer treatment and patient diagnosis. We discuss the expected future contributions of the newest imaging trends towards these goals and the challenges faced for reaching their full application in cancer research.

TROY Modulates Cancer Stem-Like Cell Properties and Gefitinib Resistance Through EMT Signaling in Non–Small Cell Lung Cancer

Targeted therapy has made breakthrough progress in the treatment of advanced non–small cell lung cancer (NSCLC) in the last 20 years. Despite that, acquired resistance of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) is an urgent clinical problem. Our study established an acquired gefitinib-resistant cell line, which exhibited epithelial–mesenchymal transition (EMT) and stem cell–like properties. Transcriptional sequencing and bioinformatics analysis revealed that TROY was significantly increased in gefitinib-resistant cells. Gene set enrichment analysis (GSEA) showed EMT was the core enriched hallmark in the resistant cells. TROY siRNA interference could overcome the gefitinib resistance with the downregulated expression of EMT and CSC markers. In addition, immunohistochemistry indicated that TROY was overexpressed in tumor samples from patients who acquired resistance to first-generation EGFR-TKI without T790M mutation and the expression of TROY was associated with poor prognosis in LUAD. Here, we provided the potential role of TROY in the resistance of targeted therapy and a new strategy to overcome the acquired resistance to EGFR-TKI in NSCLC.

Cancer Stem Cells and Their Possible Implications in Cervical Cancer: A Short Review

Cervical cancer (CC) is the fourth most common type of gynecological malignancy affecting females worldwide. Most CC cases are linked to infection with high-risk human papillomaviruses (HPV). There has been a significant decrease in the incidence and death rate of CC due to effective cervical Pap smear screening and administration of vaccines. However, this is not equally available throughout different societies. The prognosis of patients with advanced or recurrent CC is particularly poor, with a one-year relative survival rate of a maximum of 20%. Increasing evidence suggests that cancer stem cells (CSCs) may play an important role in CC tumorigenesis, metastasis, relapse, and chemo/radio-resistance, thus representing potential targets for a better therapeutic outcome. CSCs are a small subpopulation of tumor cells with self-renewing ability, which can differentiate into heterogeneous tumor cell types, thus creating a progeny of cells constituting the bulk of tumors. Since cervical CSCs (CCSC) are difficult to identify, this has led to the search for different markers (e.g., ABCG2, ITGA6 (CD49f), PROM1 (CD133), KRT17 (CK17), MSI1, POU5F1 (OCT4), and SOX2). Promising therapeutic strategies targeting CSC-signaling pathways and the CSC niche are currently under development. Here, we provide an overview of CC and CCSCs, describing the phenotypes of CCSCs and the potential of targeting CCSCs in the management of CC.

PHGDH heterogeneity potentiates cancer cell dissemination and metastasis

Cancer metastasis requires the transient activation of cellular programs enabling dissemination and seeding in distant organs1. Genetic, transcriptional and translational heterogeneity contributes to this dynamic process2,3. Metabolic heterogeneity has also been observed4, yet its role in cancer progression is less explored. Here we find that the loss of phosphoglycerate dehydrogenase (PHGDH) potentiates metastatic dissemination. Specifically, we find that heterogeneous or low PHGDH expression in primary tumours of patients with breast cancer is associated with decreased metastasis-free survival time. In mice, circulating tumour cells and early metastatic lesions are enriched with Phgdhlow cancer cells, and silencing Phgdh in primary tumours increases metastasis formation. Mechanistically, Phgdh interacts with the glycolytic enzyme phosphofructokinase, and the loss of this interaction activates the hexosamine-sialic acid pathway, which provides precursors for protein glycosylation. As a consequence, aberrant protein glycosylation occurs, including increased sialylation of integrin αvβ3, which potentiates cell migration and invasion. Inhibition of sialylation counteracts the metastatic ability of Phgdhlow cancer cells. In conclusion, although the catalytic activity of PHGDH supports cancer cell proliferation, low PHGDH protein expression non-catalytically potentiates cancer dissemination and metastasis formation. Thus, the presence of PHDGH heterogeneity in primary tumours could be considered a sign of tumour aggressiveness.

Comparative subcellular localization of NRF2 and KEAP1 during the hepatocellular carcinoma development in vivo

The activation of Nuclear Factor, Erythroid 2 Like 2 - Kelch Like ECH Associated Protein 1 (NRF2-KEAP1) signaling pathway plays a critical dual role by either protecting or promoting the carcinogenesis process. However, its activation or nuclear translocation during hepatocellular carcinoma (HCC) progression has not been addressed yet. This study characterizes the subcellular localization of both NRF2 and KEAP1 during diethylnitrosamine-induced hepatocarcinogenesis in the rat. NRF2-KEAP1 pathway was continuously activated along with the increased expression of its target genes, namely Nqo1, Hmox1, Gclc, and Ptgr1. Similarly, the nuclear translocation of NRF2, MAF, and KEAP1 increased in HCC cells from weeks 12 to 22 during HCC progression. Likewise, colocalization of NRF2 with KEAP1 was higher in the cell nuclei of HCC neoplastic nodules than in surrounding cells. Moreover, immunofluorescence analyses revealed that the interaction of KEAP1 with filamentous Actin was disrupted in HCC cells. This disruption may be contributing to the release and nuclear translocation of NRF2 since the cortical actin cytoskeleton serves as anchoring of KEAP1. In conclusion, this evidence indicates that NRF2 is progressively activated and promotes the progression of experimental HCC.

The paradigm of drug resistance in cancer: an epigenetic perspective

Innate and acquired resistance towards the conventional therapeutic regimen imposes a significant challenge for the successful management of cancer for decades. In patients with advanced carcinomas, acquisition of drug resistance often leads to tumor recurrence and poor prognosis after the first therapeutic cycle. In this context, cancer stem cells (CSCs) are considered as the prime drivers of therapy resistance in cancer due to their 'non-targetable' nature. Drug resistance in cancer is immensely influenced by different properties of CSCs such as epithelial-to-mesenchymal transition (EMT), a profound expression of drug efflux pump genes, detoxification genes, quiescence, and evasion of apoptosis, has been highlighted in this review article. The crucial epigenetic alterations that are intricately associated with regulating different mechanisms of drug resistance, have been discussed thoroughly. Additionally, special attention is drawn towards the epigenetic mechanisms behind the interaction between the cancer cells and their microenvironment which assists in tumor progression and therapy resistance. Finally, we have provided a cumulative overview of the alternative treatment strategies and epigenome-modifying therapies that show the potential of sensitizing the resistant cells towards the conventional treatment strategies. Thus, this review summarizes the epigenetic and molecular background behind therapy resistance, the prime hindrance of present day anti-cancer therapies, and provides an account of the novel complementary epi-drug-based therapeutic strategies to combat drug resistance.

Family with sequence similarity 46 member a confers chemo-resistance to ovarian carcinoma via TGF-β/Smad2 signaling

Ovarian cancer is the most lethal malignancy with depressive 5-year survival rate, mainly due to patients with advanced stages experience tumor recurrence and resistance to the current chemotherapeutic agents. Thus, exploring the underlying molecular mechanisms involved in chemo-resistance is crucial for management of treatment to improve therapeutic outcomes. In the current study, we found overexpression of FAM46A in ovarian cancer patients demonstrated an aggressive phenotype and poor outcome. Furthermore, FAM46A overexpression in ovarian cancer cells induces higher CDDP resistance. However, inhibition of FAM46A sensitized ovarian cancer cell lines to CDDP cytotoxicity both in vitro and in vivo. Mechanically, upregulation of FAM46A activated transforming growth factor-β (TGF-β)/Smad signaling and upregulated the levels of nuclear Smad2. Taken together, our results highlight the important oncogenic role of FAM46A in ovarian cancer progression and might provide a potential clinical target for patients with chemo resistant ovarian cancer.

H3K4 demethylase KDM5B regulates cancer cell identity and epigenetic plasticity

The H3K4 demethylase KDM5B is overexpressed in multiple cancer types, and elevated expression levels of KDM5B is associated with decreased survival. However, the underlying mechanistic contribution of dysregulated expression of KDM5B and H3K4 demethylation in cancer is poorly understood. Our results show that loss of KDM5B in multiple types of cancer cells leads to increased proliferation and elevated expression of cancer stem cell markers. In addition, we observed enhanced tumor formation following KDM5B depletion in a subset of representative cancer cell lines. Our findings also support a role for KDM5B in regulating epigenetic plasticity, where loss of KDM5B in cancer cells with elevated KDM5B expression leads to alterations in activity of chromatin states, which facilitate activation or repression of alternative transcriptional programs. In addition, we define KDM5B-centric epigenetic and transcriptional patterns that support cancer cell plasticity, where KDM5B depleted cancer cells exhibit altered epigenetic and transcriptional profiles resembling a more primitive cellular state. This study also provides a resource for evaluating associations between alterations in epigenetic patterning upon depletion of KDM5B and gene expression in a diverse set of cancer cells.

TGFβ: Signaling Blockade for Cancer Immunotherapy

Discovered over four decades ago, transforming growth factor β (TGFβ) is a potent pleiotropic cytokine that has context-dependent effects on most cell types. It acts as a tumor suppressor in some cancers and/or supports tumor progression and metastasis through its effects on the tumor stroma and immune microenvironment. In TGFβ-responsive tumors it can promote invasion and metastasis through epithelial-mesenchymal transformation, the appearance of cancer stem cell features, and resistance to many drug classes, including checkpoint blockade immunotherapies. Here we consider the biological activities of TGFβ action on different cells of relevance toward improving immunotherapy outcomes for patients, with a focus on the adaptive immune system. We discuss recent advances in the development of drugs that target the TGFβ signaling pathway in a tumor-specific or cell type–specific manner to improve the therapeutic window between response rates and adverse effects.

TGF-β induced reprogramming and drug resistance in triple-negative breast cells

BACKGROUND

The development of drug resistance remains to be a major cause of therapeutic failure in breast cancer patients. How drug-sensitive cells first evade drug inhibition to proliferate remains to be fully investigated.

METHODS

Here we characterized the early transcriptional evolution in response to TGF-β in the human triple-negative breast cells through bioinformatical analysis using a published RNA-seq dataset, for which MCF10A cells were treated with 5 ng/ml TGF-β1 for 0 h, 24 h, 48 h and 72 h, and the RNA-seq were performed in biological duplicates. The protein-protein interaction networks of the differentially expressed genes were constructed. KEGG enrichment analysis, cis-regulatory sequence analysis and Kaplan-Meier analysis were also performed to analyze the cellular reprograming induced by TGF-β and its contribution to the survival probability decline of breast cancer patients.

RESULT

Transcriptomic analysis revealed that cell growth was severely suppressed by TGF-β in the first 24 h but this anti-proliferate impact attenuated between 48 h and 72 h. The oncogenic actions of TGF-β happened within the same time frame with its anti-proliferative effects. In addition, sustained high expression of several drug resistance markers was observed after TGF-β treatment. We also identified 17 TGF-β induced genes that were highly correlated with the survival probability decline of breast cancer patients.

CONCLUSION

Together, TGF-β plays an important role in tumorigenesis and the development of drug resistance, which implies potential therapeutic strategies targeting the early-stage TGF-β signaling activities.

Early detection of cancer

Survival improves when cancer is detected early. However, ~50% of cancers are at an advanced stage when diagnosed. Early detection of cancer or precancerous change allows early intervention to try to slow or prevent cancer development and lethality. To achieve early detection of all cancers, numerous challenges must be overcome. It is vital to better understand who is at greatest risk of developing cancer. We also need to elucidate the biology and trajectory of precancer and early cancer to identify consequential disease that requires intervention. Insights must be translated into sensitive and specific early detection technologies and be appropriately evaluated to support practical clinical implementation. Interdisciplinary collaboration is key; advances in technology and biological understanding highlight that it is time to accelerate early detection research and transform cancer survival.

The Interplay Between TGF-β Signaling and Cell Metabolism

The transforming growth factor-β (TGF-β) signaling plays a critical role in the development and tissue homeostasis in metazoans, and deregulation of TGF-β signaling leads to many pathological conditions. Mounting evidence suggests that TGF-β signaling can actively alter metabolism in diverse cell types. Furthermore, metabolic pathways, beyond simply regarded as biochemical reactions, are closely intertwined with signal transduction. Here, we discuss the role of TGF-β in glucose, lipid, amino acid, redox and polyamine metabolism with an emphasis on how TGF-β can act as a metabolic modulator and how metabolic changes can influence TGF-β signaling. We also describe how interplay between TGF-β signaling and cell metabolism regulates cellular homeostasis as well as the progression of multiple diseases, including cancer.

Intra-epithelial non-canonical Activin A signaling safeguards prostate progenitor quiescence

The healthy prostate is a relatively quiescent tissue. Yet, prostate epithelium overgrowth is a common condition during aging, associated with urinary dysfunction and tumorigenesis. For over thirty years, TGF-β ligands have been known to induce cytostasis in a variety of epithelia, but the intracellular pathway mediating this signal in the prostate, and its relevance for quiescence, have remained elusive. Here, using mouse prostate organoids to model epithelial progenitors, we find that intra-epithelial non-canonical Activin A signaling inhibits cell proliferation in a Smad-independent manner. Mechanistically, Activin A triggers Tak1 and p38 ΜAPK activity, leading to p16 and p21 nuclear import. Spontaneous evasion from this quiescent state occurs upon prolonged culture, due to reduced Activin A secretion, a condition associated with DNA replication stress and aneuploidy. Organoids capable to escape quiescence in vitro are also able to implant with increased frequency into immunocompetent mice. This study demonstrates that non-canonical Activin A signaling safeguards epithelial quiescence in the healthy prostate, with potential implications for the understanding of cancer initiation, and the development of therapies targeting quiescent tumor progenitors.

Cell plasticity, senescence, and quiescence in cancer stem cells: Biological and therapeutic implications

Cancer stem cells (CSCs) are a distinct population of cells within tumors with capabilities of self-renewal and tumorigenicity. CSCs play a pivotal role in cancer progression, metastasis, and relapse and tumor resistance to cytotoxic therapy. Emerging scientific evidence indicates that CSCs adopt several mechanisms, driven by cellular plasticity, senescence and quiescence, to maintain their self-renewal capability and to resist tumor microenvironmental stress and treatments. These pose major hindrances for CSC-targeting anti-cancer therapies: cell plasticity maintains stemness in CSCs and renders tumor cells to acquire stem-like phenotypes, contributing to tumor heterogeneity and CSC generation; cellular senescence induces genetic reprogramming and stemness activation, leading to CSC-mediated tumor progression and metastasis; cell quienscence facilitates CSC to overcome their intrinsic vulnerabilities and therapeutic stress, inducing tumor relapse and therapy resistance. These mechanisms are subjected to spatiotemporal regulation by hypoxia, CSC niche, and extracellular matrix in the tumor microenvironment. Here we integrate the recent advances and current knowledge to elucidate the mechanisms involved in the regulation of plasticity, senescence and quiescence of CSCs and the potential therapeutic implications for the future.