Molecular characterization of the tumor microenvironment in breast cancer

The role of CAFs in therapeutic resistance in triple negative breast cancer: an emerging challenge

The tumor microenvironment (TME) is a crucial element of cancerous tissue and has emerged as a promising target for therapeutic strategies. The complex variety of stromal cells within the TME plays a vital role in determining the tumor's aggressiveness and its resistance to treatment. Tumor progression is not solely driven by cancer cells harboring genetic mutations but is also significantly influenced by non-cancerous host cells within the TME, which strongly impact tumor growth, metastasis, and the response to therapies. Cancer-associated fibroblasts (CAFs) are a diverse group of stromal cells within the TME. They play dual roles, both promoting and inhibiting tumor growth, making them intriguing targets for enhancing cancer therapies. Their significant contribution to creating a tumor-supportive environment has diminished the effectiveness of various cancer treatments, including radiation, chemotherapy, immunotherapy, and hormone therapy. Research has increasingly focused on understanding how CAFs contribute to therapy resistance in triple-negative breast cancer (TNBC) to improve treatment outcomes. However, the ways in which CAF patterns affect the TME and the response to immunotherapy in TNBC are not yet well understood and the interactions between CAFs, tumor cells, and immune cells in TNBC remain largely unexplored. In this review, we thoroughly exam ine the relationship between TNBC progression and CAF patterns. We discuss the current understanding of CAF heterogeneity, their role in tumor progression, and their impact on the tumor's response to therapeutic agents in TNBC. Additionally, we explore the potential and possible strategies for therapies targeting CAFs.

Metastasis and chemoresistance in breast cancer: Crucial function of ZEB1/2 proteins

Breast cancer remains one of the leading causes of mortality worldwide. While advancements in chemotherapy, immunotherapy, radiotherapy, and targeted therapies have significantly improved breast cancer treatment, many patients are diagnosed at advanced stages, where tumor cells exhibit aggressive behavior and therapy resistance. Understanding the mechanisms driving breast cancer progression is therefore critical. Metastasis is a major factor that drastically reduces patient prognosis and survival, accounting for most breast cancer-related deaths. ZEB proteins have emerged as key regulators of cancer metastasis. Beyond their role in metastasis, ZEB proteins also influence drug resistance. This review focuses on the role of ZEB1 and ZEB2 in regulating breast cancer metastasis. These proteins interact with components of the tumor microenvironment (TME) to drive cancer progression and metastasis. Additionally, ZEB proteins regulate angiogenesis through interactions with VEGF. Targeting ZEB proteins offers potential therapeutic benefits, particularly for aggressive breast cancer subtypes such as triple-negative breast cancer (TNBC), which often show poor therapeutic response. ZEB proteins also influence the sensitivity of breast cancer cells to chemotherapy, making them promising targets for enhancing treatment efficacy. Given their upregulation in breast cancer, ZEB proteins can serve as valuable diagnostic and prognostic markers.

Three-Dimensional Models: Biomimetic Tools That Recapitulate Breast Tissue Architecture and Microenvironment to Study Ductal Carcinoma In Situ Transition to Invasive Ductal Breast Cancer

Diagnosis of ductal carcinoma in situ (DCIS) presents a challenge as we cannot yet distinguish between those lesions that remain dormant from cases that may progress to invasive ductal breast cancer (IDC) and require therapeutic intervention. Our overall interest is to develop biomimetic three-dimensional (3D) models that more accurately recapitulate the structure and characteristics of pre-invasive breast cancer in order to study the underlying mechanisms driving malignant progression. These models allow us to mimic the microenvironment to investigate many aspects of mammary cell biology, including the role of the extracellular matrix (ECM), the interaction between carcinoma-associated fibroblasts (CAFs) and epithelial cells, and the dynamics of cytoskeletal reorganization. In this review article, we outline the significance of 3D culture models as reliable pre-clinical tools that mimic the in vivo tumor microenvironment and facilitate the study of DCIS lesions as they progress to invasive breast cancer. We also discuss the role of CAFs and other stromal cells in DCIS transition as well as the clinical significance of emerging technologies like tumor-on-chip and co-culture models.

The Microenvironment in DCIS and Its Role in Disease Progression

Ductal carcinoma in situ (DCIS) accounts for ~20% of all breast cancer diagnoses but whilst known to be a precursor of invasive breast cancer (IBC), evidence suggests only one in six patients will ever progress. A key challenge is to distinguish between those lesions that will progress and those that will remain indolent. Molecular analyses of neoplastic epithelial cells have not identified consistent differences between lesions that progressed and those that did not, and this has focused attention on the tumour microenvironment (ME).The DCIS ME is unique, complex and dynamic. Myoepithelial cells form the wall of the ductal-lobular tree and exhibit broad tumour suppressor functions. However, in DCIS they acquire phenotypic changes that bestow them with tumour promoter properties, an important evolution since they act as the primary barrier for invasion. Changes in the peri-ductal stromal environment also arise in DCIS, including transformation of fibroblasts into cancer-associated fibroblasts (CAFs). CAFs orchestrate other changes in the stroma, including the physical structure of the extracellular matrix (ECM) through altered protein synthesis, as well as release of a plethora of factors including proteases, cytokines and chemokines that remodel the ECM. CAFs can also modulate the immune ME as well as impact on tumour cell signalling pathways. The heterogeneity of CAFs, including recognition of anti-tumourigenic populations, is becoming evident, as well as heterogeneity of immune cells and the interplay between these and the adipocyte and vascular compartments. Knowledge of the impact of these changes is more advanced in IBC but evidence is starting to accumulate for a role in DCIS. Detailed in vitro, in vivo and tissue studies focusing on the interplay between DCIS epithelial cells and the ME should help to define features that can better predict DCIS behaviour.

Impact of Nanomedicine in Women's Metastatic Breast Cancer

Metastatic breast cancer is responsible for 90% of mortalities among women suffering from various types of breast cancers. Traditional cancer treatments such as chemotherapy and radiation therapy can cause significant side effects and may not be effective in many cases. However, recent advances in nanomedicine have shown great promise in the treatment of metastatic breast cancer. For example, nanomedicine demonstrated robust capacity in detection of metastatic cancers at early stages (i.e., before the metastatic cells leave the initial tumor site), which gives clinicians a timely option to change their treatment process (for example, instead of endocrine therapy they may use chemotherapy). Here recent advances in nanomedicine technology in the identification and treatment of metastatic breast cancers are reviewed.

Nuclear lamin A/C phosphorylation by loss of androgen receptor leads to cancer-associated fibroblast activation

Alterations in nuclear structure and function are hallmarks of cancer cells. Little is known about these changes in Cancer-Associated Fibroblasts (CAFs), crucial components of the tumor microenvironment. Loss of the androgen receptor (AR) in human dermal fibroblasts (HDFs), which triggers early steps of CAF activation, leads to nuclear membrane changes and micronuclei formation, independent of cellular senescence. Similar changes occur in established CAFs and are reversed by restoring AR activity. AR associates with nuclear lamin A/C, and its loss causes lamin A/C nucleoplasmic redistribution. AR serves as a bridge between lamin A/C and the protein phosphatase PPP1. Loss of AR decreases lamin-PPP1 association and increases lamin A/C phosphorylation at Ser 301, a characteristic of CAFs. Phosphorylated lamin A/C at Ser 301 binds to the regulatory region of CAF effector genes of the myofibroblast subtype. Expression of a lamin A/C Ser301 phosphomimetic mutant alone can transform normal fibroblasts into tumor-promoting CAFs.

The extracellular matrix in solid tumor immunotherapy

The extracellular matrix (ECM) of solid tumors impacts the antitumor activities of CD8+ T and natural killer (NK) cells in a variety of ways. Cell motility is restricted by the tumor ECM which creates physical barriers. The tumor ECM directly alter the phenotypes and functions of cytotoxic lymphocytes, and indirectly influences immunological synapse-mediated interactions between cytotoxic lymphocytes and cancer cells. Therefore, strategies to improve solid tumor immunotherapy should be established by considering complex ternary interactions between cytotoxic lymphocytes, cancer cells, and the tumor ECM. Novel bioengineering tools approximating key characteristics of the tumor ECM, such as in vitro reconstituted 3D ECMs and microfluidics are valuable from a fundamental study viewpoint and from a translational perspective, aiming to enable systematic screening approaches.

CD44v5 domain regulates crosstalk between TNBC cells and tumor-associated macrophages by enhancing the IL-4R/STAT3 axis

Triple-negative breast cancer (TNBC) has greater infiltration of M2-like macrophages (TAMs), which enhances cancer cell invasion and leads to a poor prognosis. TNBC progression is mediated by both tumor cells and the tumor microenvironment (TME). Here we elucidate the mechanism of the interaction between TNBC cells and TAMs. In this study, we confirmed that CD44v5 is highly expressed in TNBC, which drives TNBC cell metastasis and promotes TAM polarization by co-localizing with IL4Rα and inhibiting its internalization and degradation, thereby promoting activation of the STAT3/IL6 signaling axis. At the same time, TAMs also facilitate TNBC cell metastasis by secreting IL-4, IL-6, and other cytokines, in which the IL-4/IL-4R/STAT3/IL-6 signaling axis plays the same role for TNBC cells responding to TAMs. Moreover, we found that the above progress could be suppressed when the CD44v5 domain was blocked. We demonstrated that the CD44v5/IL-4R/STAT3/IL-6 signaling pathway plays a key role in TNBC cell metastasis, and in TNBC cells inducing TAM polarization and responding to TAMs, promoting metastasis. Collectively, we suggest that the CD44v5 domain may be a promising target for regulating the TME of TNBC as well as treating TNBC.

3D Bioprinted Tumor-Stroma Models of Triple-Negative Breast Cancer Stem Cells for Preclinical Targeted Therapy Evaluation

Breast cancer stem cells (CSCs) play a pivotal role in therapy resistance and tumor relapse, emphasizing the need for reliable in vitro models that recapitulate the complexity of the CSC tumor microenvironment to accelerate drug discovery. We present a bioprinted breast CSC tumor-stroma model incorporating triple-negative breast CSCs (TNB-CSCs) and stromal cells (human breast fibroblasts), within a breast-derived decellularized extracellular matrix bioink. Comparison of molecular signatures in this model with different clinical subtypes of bioprinted tumor-stroma models unveils a unique molecular profile for artificial CSC tumor models. We additionally demonstrate that the model can recapitulate the invasive potential of TNB-CSC. Surface-enhanced Raman scattering imaging allowed us to monitor the invasive potential of tumor cells in deep z-axis planes, thereby overcoming the depth-imaging limitations of confocal fluorescence microscopy. As a proof-of-concept application, we conducted high-throughput drug testing analysis to assess the efficacy of CSC-targeted therapy in combination with conventional chemotherapeutic compounds. The results highlight the usefulness of tumor-stroma models as a promising drug-screening platform, providing insights into therapeutic efficacy against CSC populations resistant to conventional therapies.

Cancer-stromal cell interactions in breast cancer brain metastases induce glycocalyx-mediated resistance to HER2-targeting therapies

Brain metastatic breast cancer is particularly lethal largely due to therapeutic resistance. Almost half of the patients with metastatic HER2-positive breast cancer develop brain metastases, representing a major clinical challenge. We previously described that cancer-associated fibroblasts are an important source of resistance in primary tumors. Here, we report that breast cancer brain metastasis stromal cell interactions in 3D cocultures induce therapeutic resistance to HER2-targeting agents, particularly to the small molecule inhibitor of HER2/EGFR neratinib. We investigated the underlying mechanisms using a synthetic Notch reporter system enabling the sorting of cancer cells that directly interact with stromal cells. We identified mucins and bulky glycoprotein synthesis as top-up-regulated genes and pathways by comparing the gene expression and chromatin profiles of stroma-contact and no-contact cancer cells before and after neratinib treatment. Glycoprotein gene signatures were also enriched in human brain metastases compared to primary tumors. We confirmed increased glycocalyx surrounding cocultures by immunofluorescence and showed that mucinase treatment increased sensitivity to neratinib by enabling a more efficient inhibition of EGFR/HER2 signaling in cancer cells. Overexpression of truncated MUC1 lacking the intracellular domain as a model of increased glycocalyx-induced resistance to neratinib both in cell culture and in experimental brain metastases in immunodeficient mice. Our results highlight the importance of glycoproteins as a resistance mechanism to HER2-targeting therapies in breast cancer brain metastases.

Epigenetic deregulation in breast cancer microenvironment: Implications for tumor progression and therapeutic strategies

Breast cancer comprises a substantial proportion of cancer diagnoses in women and is a primary cause of cancer-related mortality. While hormone-responsive cases generally have a favorable prognosis, the aggressive nature of triple-negative breast cancer presents challenges, with intrinsic resistance to established treatments being a persistent issue. The complexity intensifies with the emergence of acquired resistance, further complicating the management of breast cancer. Epigenetic changes, encompassing DNA methylation, histone and RNA modifications, and non-coding RNAs, are acknowledged as crucial contributors to the heterogeneity of breast cancer. The unique epigenetic landscape harbored by each cellular component within the tumor microenvironment (TME) adds great diversity to the intricate regulations which influence therapeutic responses. The TME, a sophisticated ecosystem of cellular and non-cellular elements interacting with tumor cells, establishes an immunosuppressive microenvironment and fuels processes such as tumor growth, angiogenesis, and extracellular matrix remodeling. These factors contribute to challenging conditions in cancer treatment by fostering a hypoxic environment, inducing metabolic stress, and creating physical barriers to drug delivery. This article delves into the complex connections between breast cancer treatment response, underlying epigenetic changes, and vital interactions within the TME. To restore sensitivity to treatment, it emphasizes the need for combination therapies considering epigenetic changes specific to individual members of the TME. Recognizing the pivotal role of epigenetics in drug resistance and comprehending the specificities of breast TME is essential for devising more effective therapeutic strategies. The development of reliable biomarkers for patient stratification will facilitate tailored and precise treatment approaches.

Progression from ductal carcinoma in situ to invasive breast cancer: molecular features and clinical significance

Ductal carcinoma in situ (DCIS) represents pre-invasive breast carcinoma. In untreated cases, 25-60% DCIS progress to invasive ductal carcinoma (IDC). The challenge lies in distinguishing between non-progressive and progressive DCIS, often resulting in over- or under-treatment in many cases. With increasing screen-detected DCIS in these years, the nature of DCIS has aroused worldwide attention. A deeper understanding of the biological nature of DCIS and the molecular journey of the DCIS-IDC transition is crucial for more effective clinical management. Here, we reviewed the key signaling pathways in breast cancer that may contribute to DCIS initiation and progression. We also explored the molecular features of DCIS and IDC, shedding light on the progression of DCIS through both inherent changes within tumor cells and alterations in the tumor microenvironment. In addition, valuable research tools utilized in studying DCIS including preclinical models and newer advanced technologies such as single-cell sequencing, spatial transcriptomics and artificial intelligence, have been systematically summarized. Further, we thoroughly discussed the clinical advancements in DCIS and IDC, including prognostic biomarkers and clinical managements, with the aim of facilitating more personalized treatment strategies in the future. Research on DCIS has already yielded significant insights into breast carcinogenesis and will continue to pave the way for practical clinical applications.

Advances and challenges in cancer immunoprevention and immune interception

Invasive cancers typically evade immune surveillance through profound local and systemic immunosuppression, preventing their elimination or control. Targeting immune interventions to prevent or intercept premalignant lesions, before significant immune dysregulation has occurred, may be a more successful strategy. The field of cancer immune interception and prevention is nascent, and the scientific community has been slow to embrace this potentially most rational approach to reducing the global burden of cancer. This may change due to recent promising advances in cancer immunoprevention including the use of vaccines for the prevention of viral cancers, the use of cancer-associated antigen vaccines in the setting of precancers, and the development of cancer-preventative vaccines for high-risk individuals who are healthy but carry cancer-associated heritable genetic mutations. Furthermore, there is increasing recognition of the importance of cancer prevention and interception by national cancer organizations. The National Cancer Institute (NCI) recently released the National Cancer Plan, which includes cancer prevention among the top priorities of the institute. The NCI's Division of Cancer Prevention has been introducing new funding opportunities for scientists with an interest in the field of cancer prevention: The Cancer Prevention-Interception Targeted Agent Discovery Program and The Cancer Immunoprevention Network. Moreover, the Human Tumor Atlas Network is spearheading the development of a precancer atlas to better understand the biology of pre-invasive changes, including the tissue microenvironment and the underlying genetics that drive carcinogenesis. These data will inform the development of novel immunoprevention/immuno-interception strategies. International cancer foundations have also started recognizing immunoprevention and immune interception with the American Association for Cancer Research, Cancer Research UK and the Society for Immunotherapy of Cancer each implementing programming focused on this area. This review will present recent advances, opportunities, and challenges in the emerging field of cancer immune prevention and immune interception.

Mechanosensitive TRPV4 channel guides maturation and organization of the bilayered mammary epithelium

Biophysical cues from the cell microenvironment are detected by mechanosensitive components at the cell surface. Such machineries convert physical information into biochemical signaling cascades within cells, subsequently leading to various cellular responses in a stimulus-dependent manner. At the surface of extracellular environment and cell cytoplasm exist several ion channel families that are activated by mechanical signals to direct intracellular events. One of such channel is formed by transient receptor potential cation channel subfamily V member, TRPV4 that is known to act as a mechanosensor in wide variaty of tissues and control ion-influx in a spatio-temporal way. Here we report that TRPV4 is prominently expressed in the stem/progenitor cell populations of the mammary epithelium and seems important for the lineage-specific differentiation, consequently affecting mechanical features of the mature mammary epithelium. This was evident by the lack of several markers for mature myoepithelial and luminal epithelial cells in TRPV4-depleted cell lines. Interestingly, TRPV4 expression is controlled in a tension-dependent manner and it also impacts differentation process dependently on the stiffness of the microenvironment. Furthermore, such cells in a 3D compartment were disabled to maintain normal mammosphere structures and displayed abnormal lumen formation, size of the structures and disrupted cellular junctions. Mechanosensitive TRPV4 channel therefore act as critical player in the homeostasis of normal mammary epithelium through sensing the physical environment and guiding accordingly differentiation and structural organization of the bilayered mammary epithelium.

MiR-200c reprograms fibroblasts to recapitulate the phenotype of CAFs in breast cancer progression

Mesenchymal-epithelial plasticity driving cancer progression in cancer-associated fibroblasts (CAFs) is undetermined. This work identifies a subgroup of CAFs in human breast cancer exhibiting mesenchymal-to-epithelial transition (MET) or epithelial-like profile with high miR-200c expression. MiR-200c overexpression in fibroblasts is sufficient to drive breast cancer aggressiveness. Oxidative stress in the tumor microenvironment induces miR-200c by DNA demethylation. Proteomics, RNA-seq and functional analyses reveal that miR-200c is a novel positive regulator of NFκB-HIF signaling via COMMD1 downregulation and stimulates pro-tumorigenic inflammation and glycolysis. Reprogramming fibroblasts toward MET via miR-200c reduces stemness and induces a senescent phenotype. This pro-tumorigenic profile in CAFs fosters carcinoma cell resistance to apoptosis, proliferation and immunosuppression, leading to primary tumor growth, metastases, and resistance to immuno-chemotherapy. Conversely, miR-200c inhibition in fibroblasts restrains tumor growth with abated oxidative stress and an anti-tumorigenic immune environment. This work determines the mechanisms by which MET in CAFs via miR-200c transcriptional enrichment with DNA demethylation triggered by oxidative stress promotes cancer progression. CAFs undergoing MET trans-differentiation and senescence coordinate heterotypic signaling that may be targeted as an anti-cancer strategy.

The miR-1290/OGN axis in ovarian cancer-associated fibroblasts modulates cancer cell proliferation and invasion

Despite receiving first-line treatment, ovarian cancer patients continue to experience a high rate of recurrence; nearly all women with ovarian cancer develop chemoresistance and succumb to the disease. In this study, cancer-associated fibroblasts (CAFs) and normal fibroblasts (NFs) were isolated from tumor-containing and normal omenta, respectively, and the downregulation of osteoglycin (OGN) in CAFs was observed. OGN overexpression in CAFs significantly inhibited ovarian cancer cell viability, DNA synthesis, and cell invasion. OGN overexpression also changed epithelial-mesenchymal transition (EMT) markers and promoted mTOR and Akt phosphorylation in ovarian cancer cells. miR-1290 targeted OGN and inhibited OGN expression. miR-1290 overexpression in CAFs significantly promoted ovarian cancer cell viability, DNA synthesis, and cell invasion. Moreover, miR-1290 overexpression in CAFs also changed EMT markers and promoted mTOR and Akt phosphorylation within ovarian carcinoma cells. Finally, when ovarian cancer cells in a conditioned medium derived from CAFs co-transduced with miR-1290 mimics and OGN-OE were cultured, the effects of miR-1290 overexpression were partially reversed by OGN overexpression. In nude mouse xenograft tumor models, OGN overexpression in CAFs suppressed tumor growth, whereas miR-1290 overexpression in CAFs increased tumor growth. In conclusion, a miRNA/mRNA axis in ovarian cancer CAFs modulating the proliferative and invasive abilities of ovarian cancer cells, possibly via the Akt/mTOR pathway, was demonstrated.

Unveiling a pH-Responsive Dual-Androgen-Blocking Magnetic Molecularly Imprinted Polymer for Enhanced Synergistic Therapy of Prostate Cancer

Prostate cancer is the most common malignancy diagnosed in men. Androgens are directly related to its pathogenesis. Inhibition of the androgen receptor (AR) is considered to be the most promising therapeutic approach for the treatment of prostate cancer. In this study, a new type of pH-responsive dual androgen-blocking nanodrug (FASC MIPs) based on a molecularly imprinted polymer has been designed and synthesized. The nanodrug could selectively sequester testosterone from the prostate tumor through specific molecular imprinting sites and simultaneously deliver the AR inhibitory drug bicalutamide, which ultimately leads to enhanced synergistic therapy of prostate cancer. FASC MIPs demonstrate excellent pH responsiveness in a simulated tumor microenvironment due to the presence of chitosan and significantly inhibit the growth of prostate cancer cells (LNCaP cells) by blocking the G1 phase of cytokinesis. Additionally, the nanodrug also displayed excellent antitumor properties in a xenograft mouse model of prostate cancer without any sign of detrimental effects on healthy tissues and organs. Both in vitro and in vivo studies verified the augmented and synergistic therapeutic effects of FASC MIPs, and the proposed dual-androgen-blocking strategy could explore novel avenues in prostate cancer treatment.

The Role of Chemokines in Orchestrating the Immune Response to Pancreatic Ductal Adenocarcinoma

Chemokines are small molecules that function as chemotactic factors which regulate the migration, infiltration, and accumulation of immune cells. Here, we comprehensively assess the structural and functional role of chemokines, examine the effects of chemokines that are present in the pancreatic ductal adenocarcinoma (PDAC) tumor microenvironment (TME), specifically those produced by cancer cells and stromal components, and evaluate their impact on immune cell trafficking, both in promoting and suppressing anti-tumor responses. We further explore the impact of chemokines on patient outcomes in PDAC and their role in the context of immunotherapy treatments, and review clinical trials that have targeted chemokine receptors and ligands in the treatment of PDAC. Lastly, we highlight potential strategies that can be utilized to harness chemokines in order to increase cytotoxic immune cell infiltration and the anti-tumor effects of immunotherapy.

Unraveling the Role of Ras Homolog Enriched in Brain (Rheb1 and Rheb2): Bridging Neuronal Dynamics and Cancer Pathogenesis through Mechanistic Target of Rapamycin Signaling

Ras homolog enriched in brain (Rheb1 and Rheb2), small GTPases, play a crucial role in regulating neuronal activity and have gained attention for their implications in cancer development, particularly in breast cancer. This study delves into the intricate connection between the multifaceted functions of Rheb1 in neurons and cancer, with a specific focus on the mTOR pathway. It aims to elucidate Rheb1's involvement in pivotal cellular processes such as proliferation, apoptosis resistance, migration, invasion, metastasis, and inflammatory responses while acknowledging that Rheb2 has not been extensively studied. Despite the recognized associations, a comprehensive understanding of the intricate interplay between Rheb1 and Rheb2 and their roles in both nerve and cancer remains elusive. This review consolidates current knowledge regarding the impact of Rheb1 on cancer hallmarks and explores the potential of Rheb1 as a therapeutic target in cancer treatment. It emphasizes the necessity for a deeper comprehension of the molecular mechanisms underlying Rheb1-mediated oncogenic processes, underscoring the existing gaps in our understanding. Additionally, the review highlights the exploration of Rheb1 inhibitors as a promising avenue for cancer therapy. By shedding light on the complicated roles between Rheb1/Rheb2 and cancer, this study provides valuable insights to the scientific community. These insights are instrumental in guiding the identification of novel targets and advancing the development of effective therapeutic strategies for treating cancer.

Prognostic Value and Therapeutic Significance of CCL Chemokines in Gastric Cancer

BACKGROUND

Gastric cancer is one of the most common malignant tumours of the gastrointestinal tract, which has a significant negative impact on human health.

AIMS

CCL chemokines play important roles in a variety of tumor microenvironments; nevertheless, gastric cancer has surprisingly limited associations with CCL chemokines.

METHODS

In our study, we comprehensively utilized bioinformatics analysis tools and databases such as cBioPortal, UALCAN, GEPIA, GeneMANIA, STRING, and TRRUST to clarify the clinical significance and biology function of CCL chemokines in gastric cancer.

RESULTS

The mRNA expression levels of CCL1/3/4/5/7/8/14/15/18/20/21/22/26 were up-regulated, while the mRNA expression levels of CCL2/11/13/16/17/19/23/24/25/28 were down-regulated. The chemokine significantly associated with the pathological stage of gastric cancer is CCL2/11/19/21. In gastric cancer, the expression level of CCL chemokines was not associated with disease-free survival, but low expression of CCL14 was significantly associated with longer overall survival. Therein, associated with the regulation of CCL chemokines are only 10 transcription factors (RELA, NFKB1, STAT6, IRF3, REL, SPI1, STAT1, STAT3, JUN and SP1). The major biological process and functional enrichment of CCL chemokines are to induce cell-directed migration.

CONCLUSION

These results may indicate that CCL chemokines may be immunotherapeutic targets and promising prognostic biomarkers for gastric cancer.

Brain metastasis-associated fibroblasts secrete fucosylated PVR/CD155 that induces breast cancer invasion

Brain metastasis cancer-associated fibroblasts (bmCAFs) are emerging as crucial players in the development of breast cancer brain metastasis (BCBM), but our understanding of the underlying molecular mechanisms is limited. In this study, we aim to elucidate the pathological contributions of fucosylation (the post-translational modification of proteins by the dietary sugar L-fucose) to tumor-stromal interactions that drive the development of BCBM. Here, we report that patient-derived bmCAFs secrete high levels of polio virus receptor (PVR), which enhance the invasive capacity of BC cells. Mechanistically, we find that HIF1α transcriptionally upregulates fucosyltransferase 11, which fucosylates PVR, triggering its secretion from bmCAFs. Global phosphoproteomic analysis of BC cells followed by functional verification identifies cell-cell junction and actin cytoskeletal signaling as modulated by bmCAF-secreted, -fucosylated PVR. Our findings delineate a hypoxia- and fucosylation-regulated mechanism by which bmCAFs contribute to the invasiveness of BCBM in the brain.

Treatment efficacy of low-dose 5-fluorouracil with ultrasound in mediating 5-fluorouracil-loaded microbubble cavitation in head and neck cancer

Over the past 50 years, 5-fluorouracil (5-FU) has played a critical role in the systemic chemotherapy of cancer patients. Bolus intravenous (IV) 5-FU infusion has been used due to the limitation of its extremely short half-life (10-15 min). This study used ultrasound (US) mediating 5-FU-loaded microbubbles (MBs) cavitation as a tool to increase local intratumoral 5-FU levels with a reduced dose of 5-FU (a single IV injection of 2.5 mg/kg instead of a single intraperitoneal injection of 25-200 mg/kg as used in previous studies in mice). The 5-FU-MBs were prepared with a 132 mg/mL albumin solution and a 0.30 mg/mL 5-FU solution. The diameters of the MBs and 5-FU-MBs were 1.24 ± 0.85 and 2.00 ± 0.53 µm (mean ± SEM), respectively, and the maximum loading efficiency of 5-FU on MBs was 19.04 ± 0.25%. In the in vitro study, the cell viabilities of 5-FU and 5-FU-MBs did not differ significantly, but compared with the 5-FU-MBs treatment-alone group, cell toxicity increased to 31% in the 5-FU-MBs + US group (p < 0.001). The biodistribution results indicated that the 5-FU levels of the tumors in small animals were significant higher for the 5-FU-MBs + US treatment than for either the 5-FU-MBs or 5-FU treatment with low 5-FU systemic treatment doses (2.5 mg/kg 5-FU IV). In small-animal treatment, 2.5 mg/kg 5-FU therapeutic IV doses injected into mice caused a more-significant reduction in tumor growth in the 5-FU-MBs + US group (65.9%) than in the control group after 34 days of treatment.

3D bioprinted breast tumor-stroma models for pre-clinical drug testing

The use of three-dimensional (3D) bioprinting has been proposed for the reproducible production of 3D disease models that can be used for high-throughput drug testing and personalized medicine. However, most such models insufficiently reproduce the features and environment of real tumors. We report the development of bioprinted in vitro 3D tumor models for breast cancer, which physically and biochemically mimic important aspects of the native tumor microenvironment, designed to study therapeutic efficacy. By combining a mix of breast decellularized extracellular matrix and methacrylated hyaluronic acid with tumor-derived cells and non-cancerous stromal cells of biological relevance to breast cancer, we show that biological signaling pathways involved in tumor progression can be replicated in a carefully designed tumor-stroma environment. Finally, we demonstrate proof-of-concept application of these models as a reproducible platform for investigating therapeutic responses to commonly used chemotherapeutic agents.

The Significance of Microenvironmental and Circulating Lactate in Breast Cancer

Lactate represents the main product of pyruvate reduction catalyzed by the lactic dehydrogenase family of enzymes. Cancer cells utilize great quantities of glucose, shifting toward a glycolytic metabolism. With the contribution of tumor stromal cells and under hypoxic conditions, this leads toward the acidification of the extracellular matrix. The ability to shift between different metabolic pathways is a characteristic of breast cancer cells and is associated with an aggressive phenotype. Furthermore, the preliminary scientific evidence concerning the levels of circulating lactate in breast cancer points toward a correlation between hyperlactacidemia and poor prognosis, even though no clear linkage has been demonstrated. Overall, lactate may represent a promising metabolic target that needs to be investigated in breast cancer.

Human Ductal Carcinoma In Situ: Advances and Future Perspectives

Due to widespread adoption of screening mammography, there has been a significant increase in new diagnoses of ductal carcinoma in situ (DCIS). However, DCIS outcomes remain unclear. A large fraction of human DCIS (>50%) may not need the multimodality treatment options currently offered to all DCIS patients. More importantly, while we may be overtreating many, we cannot identify those most at risk of invasion or metastasis following a DCIS diagnosis. This review summarizes the studies that have furthered our understanding of DCIS pathology and mechanisms of invasive progression by using advanced technologies including spatial genomics, transcriptomics, and multiplex proteomics. This review also highlights a need for rethinking DCIS with a more focused view on epithelial states and programs and their cross talk with the microenvironment.

Bioinformatics in Early Cancer Detection

Bioinformatics is a pretty recent branch of biology that encompasses the use of algebraic, analytic, and computing approaches to the processing and interpretation of biological information. A wide term, "bioinformatics" refers to the use of digital technology to study biological processes using high-dimensional data collected from many resources. The design and testing of the software tools required to evaluate the information are the core of bioinformatics research, which is conducted in great portions in silico and typically involves the synthesis of new learning from available data. Early diagnosis of cancer results in improved prognosis, but at the same time, it is difficult to conform to diagnosis at a very early stage. The use of DNA microarrays and proteomics studies for large-scale gene expression research has advanced technology, thus elevating the significance of bioinformatics tools. In today's research, wet experimentation and the application of bioinformatics analytics go side by side. Molecular profiling of tumor biopsies is becoming more and more crucial to both cancer research and the treatment of cancer.

A molecular landscape of quiescence and proliferation highlights the role of Pten in mammary gland acinogenesis

Cell context is key for cell state. Using physiologically relevant models of laminin-rich extracellular matrix (lrECM) induction of mammary epithelial cell quiescence and differentiation, we provide a landscape of the key molecules for the proliferation-quiescence decision, identifying multiple layers of regulation at the mRNA and protein levels. Quiescence occurred despite activity of Fak (also known as PTK2), Src and phosphoinositide 3-kinases (PI3Ks), suggesting the existence of a disconnecting node between upstream and downstream proliferative signalling. Pten, a lipid and protein phosphatase, fulfils this role, because its inhibition increased proliferation and restored signalling via the Akt, mTORC1, mTORC2 and mitogen-activated protein kinase (MAPK) pathways. Pten and laminin levels were positively correlated in developing murine mammary epithelia, and Pten localized apicolaterally in luminal cells in ducts and near the nascent lumen in terminal end buds. Consistently, in three-dimensional acinogenesis models, Pten was required for triggering and sustaining quiescence, polarity and architecture. The multilayered regulatory circuitry that we uncovered provides an explanation for the robustness of quiescence within a growth-suppressive microenvironment, which could nonetheless be disrupted by perturbations in master regulators such as Pten.

Smart Nanozymes for Cancer Therapy: The Next Frontier in Oncology

Nanomaterials that mimic the catalytic activity of natural enzymes in the complex biological environment of the human body are called nanozymes. Recently, nanozyme systems have been reported with diagnostic, imaging, and/or therapeutic capabilities. Smart nanozymes strategically exploit the tumor microenvironment (TME) by the in situ generation of reactive species or by the modulation of the TME itself to result in effective cancer therapy. This topical review focuses on such smart nanozymes for cancer diagnosis, and therapy modalities with enhanced therapeutic effects. The dominant factors that guide the rational design and synthesis of nanozymes for cancer therapy include an understanding of the dynamic TME, structure-activity relationships, surface chemistry for imparting selectivity, and site-specific therapy, and stimulus-responsive modulation of nanozyme activity. This article presents a comprehensive analysis of the subject including the diverse catalytic mechanisms of different types of nanozyme systems, an overview of the TME, cancer diagnosis, and synergistic cancer therapies. The strategic application of nanozymes in cancer treatment can well be a game changer in future oncology. Moreover, recent developments may pave the way for the deployment of nanozyme therapy into other complex healthcare challenges, such as genetic diseases, immune disorders, and ageing.

Cancer stem cells as the source of tumor associated myoepithelial cells in the tumor microenvironment developing ductal carcinoma in situ

The heterogeneous cell population in the stromal microenvironment is considered to be attributed to the multiple sources from which the cells originate. Tumor associated myoepithelial cells (TAMEs) are one of the most important populations in the tumor microenvironment (TME) especially in breast cancer. On the other hand, cancer stem cells (CSCs) have previously been described to be the origin of tumor-associated cellular components in the TME. We prepared a cancer stem cell model converting mouse-induced pluripotent stem cells (miPSCs) in the presence of conditioned medium of breast cancer cell line MDA-MB-231 cells. The converted cells developed tumors progressing into invasive carcinoma with ductal carcinoma in situ (DCIS) like structure when transplanted into mouse mammary fat pads. The primary cultured cells from the tumor further exhibited markers of CSC such as Sox2, Oct3/4, - CD133 and EpCAM, and mammary gland-related TAME markers such as α-smooth muscle actin, cytokeratin 8, whey acidic protein, prolactin receptor and progesterone receptor as well. These results indicated that the CSCs could be an origin of TAMEs contributing to mammary gland epithelial cell differentiation and the progression to invasive carcinoma during tumor development. The gene expression profiles confirmed the enhanced signaling pathways of PI3K/AKT and MAPK, which have been demonstrated to be enriched in the CSC models, together with the estrogen receptor signaling which was peculiar to mammary gland-derived character.

Catecholamines Promote Ovarian Cancer Progression through Secretion of CXC-Chemokines

Considerable evidence has accumulated in the last decade supporting the notion that chronic stress is closely related to the growth, metastasis, and angiogenesis of ovarian cancer. In this study, we analyzed the conditioned media in SKOV3 ovarian cancer cell lines treated with catecholamines to identify secreted proteins responding to chronic stress. Here, we observed that epinephrine and norepinephrine enhanced the secretion and mRNA expression of CXC-chemokines (CXCL1, 2, 3, and 8). Neutralizing antibodies to CXCL8 and CXCL8 receptor (CXCR2) inhibitors significantly reduced catecholamine-mediated invasion of SKOV3 cells. Finally, we found that the concentration of CXCL1 and CXCL8 in the plasma of ovarian cancer patients increased with stage progression. Taken together, these findings suggest that stress-related catecholamines may influence ovarian cancer progression through the secretion of CXC-chemokines.

The role of cancer-associated fibroblasts in breast cancer metastasis

Breast cancer deaths are primarily caused by metastasis. There are several treatment options that can be used to treat breast cancer. There are, however, a limited number of treatments that can either prevent or inhibit the spread of breast tumor metastases. Thus, novel therapeutic strategies are needed. Studies have increasingly focused on the importance of the tumor microenvironment (TME) in metastasis of breast cancer. As the most abundant cells in the TME, cancer-associated fibroblasts (CAFs) play important roles in cancer pathogenesis. They can remodel the structure of the extracellular matrix (ECM) and engage in crosstalk with cancer cells or other stroma cells by secreting growth factors, cytokines, and chemokines, as well as components of the ECM, which assist the tumor cells to invade through the TME and cause distant metastasis. Clinically, CAFs not only foster the initiation, growth, angiogenesis, invasion, and metastasis of breast cancer but also serve as biomarkers for diagnosis, therapy, and prediction of prognosis. In this review, we summarize the biological characteristics and subtypes of CAFs and their functions in breast cancer metastasis, focusing on their important roles in the diagnosis, prognosis, and treatment of breast cancer. Recent studies suggest that CAFs are vital partners of breast cancer cells that assist metastasis and may represent ideal targets for prevention and treatment of breast cancer metastasis.

A role for fibroblast-derived SASP factors in the activation of pyroptotic cell death in mammary epithelial cells

In normal tissue homeostasis, bidirectional communication between different cell types can shape numerous biological outcomes. Many studies have documented instances of reciprocal communication between fibroblasts and cancer cells that functionally change cancer cell behavior. However, less is known about how these heterotypic interactions shape epithelial cell function in the absence of oncogenic transformation. Furthermore, fibroblasts are prone to undergo senescence, which is typified by an irreversible cell cycle arrest. Senescent fibroblasts are also known to secrete various cytokines into the extracellular space; a phenomenon that is termed the senescence-associated secretory phenotype (SASP). While the role of fibroblast-derived SASP factors on cancer cells has been well studied, the impact of these factors on normal epithelial cells remains poorly understood. We discovered that treatment of normal mammary epithelial cells with conditioned media from senescent fibroblasts (SASP CM) results in a caspase-dependent cell death. This capacity of SASP CM to cause cell death is maintained across multiple senescence-inducing stimuli. However, the activation of oncogenic signaling in mammary epithelial cells mitigates the ability of SASP CM to induce cell death. Despite the reliance of this cell death on caspase activation, we discovered that SASP CM does not cause cell death by the extrinsic or intrinsic apoptotic pathway. Instead, these cells die by an NLRP3, caspase-1, and gasdermin D-dependent induction of pyroptosis. Taken together, our findings reveal that senescent fibroblasts can cause pyroptosis in neighboring mammary epithelial cells, which has implications for therapeutic strategies that perturb the behavior of senescent cells.

Deciphering Stromal Changes between Metastatic and Non-metastatic Canine Mammary Carcinomas

Cancer-associated stroma (CAS) is widely recognized to influence development and progression of epithelial tumours including breast cancer. Canine mammary tumours (CMTs) such as simple canine mammary carcinomas represent valuable models for human breast cancer also with respect to stromal reprogramming. However, it remains unclear whether and how CAS changes in metastatic tumours compared to non-metastatic ones. To characterize stromal changes between metastatic and non-metastatic CMTs and identify potential drivers of tumour progression, we analysed CAS and matched normal stroma from 16 non-metastatic and 15 metastatic CMTs by RNA-sequencing of microdissected FFPE tissue. We identified 1438 differentially regulated genes between CAS and normal stroma, supporting previous results demonstrating stromal reprogramming in CMTs to be comparable with CAS in human breast cancer and validating deregulation of pathways and genes associated with CAS. Using primary human fibroblasts activated by treatment with TGFβ, we demonstrate some of the strongest expression changes to be conserved in fibroblasts across species. Furthermore, we identify 132 differentially expressed genes between CAS from metastatic and non-metastatic tumours, with strong changes in pathways including chemotaxis, regulation of apoptosis, immune response and TGFβ signalling and validate deregulation of several targets using RT-qPCR. Finally, we identify specific upregulation of COL6A5, F5, GALNT3, CIT and MMP11 in metastatic CAS, suggesting high stromal expression of these targets to be linked to malignancy and metastasis of CMTs. In summary, our data present a resource supporting further research into stromal changes of the mammary gland in relation to metastasis with implications for both canine and human mammary cancer.

Epigenetic regulation of cancer-associated fibroblast heterogeneity

Cancer-associated fibroblasts (CAFs), a significant component of the tumor microenvironment (TME), contribute to cancer progression through the secretion of extracellular matrix (ECM), growth factors, and metabolites. It is now well recognized that CAFs are a heterogenous population with ablation experiments leading to reduced tumor growth and single-cell RNA sequencing demonstrating CAF subgroups. CAFs lack genetic mutations yet substantially differ from their normal stromal precursors. Here, we review epigenetic changes in CAF maturation, focusing on DNA methylation and histone modifications. DNA methylation changes in CAFs have been demonstrated globally, while roles of methylation at specific genes affect tumor growth. Further, loss of CAF histone methylation and gain of histone acetylation has been shown to promote CAF activation and tumor promotion. Many CAF activating factors, such as transforming growth factor β (TGFβ), lead to these epigenetic changes. MicroRNAs (miRNAs) serve as targets and orchestrators of epigenetic modifications that influence gene expression. Bromodomain and extra-terminal domain (BET), an epigenetic reader, recognizes histone acetylation and activates the transcription of genes leading to the pro-tumor phenotype of CAFs.

LncRNA modulates Hippo-YAP signaling to reprogram iron metabolism

Iron metabolism dysregulation is tightly associated with cancer development. But the underlying mechanisms remain poorly understood. Increasing evidence has shown that long noncoding RNAs (lncRNAs) participate in various metabolic processes via integrating signaling pathway. In this study, we revealed one iron-triggered lncRNA, one target of YAP, LncRIM (LncRNA Related to Iron Metabolism, also named ZBED5-AS1 and Loc729013), which effectively links the Hippo pathway to iron metabolism and is largely independent on IRP2. Mechanically, LncRIM directly binds NF2 to inhibit NF2-LATS1 interaction, which causes YAP activation and increases intracellular iron level via DMT1 and TFR1. Additionally, LncRIM-NF2 axis mediates cellular iron metabolism dependent on the Hippo pathway. Clinically, high expression of LncRIM correlates with poor patient survival, suggesting its potential use as a biomarker and therapeutic target. Taken together, our study demonstrated a novel mechanism in which LncRIM-NF2 axis facilitates iron-mediated feedback loop to hyperactivate YAP and promote breast cancer development.

Molecular characterization of colorectal mucinous adenocarcinoma and adenocarcinoma, not otherwise specified, identified by multiomic data analysis

Adenocarcinoma not otherwise specified (AC) and mucinous adenocarcinoma (MC) have different biological behaviors and clinical features. We utilized our previous proteomic data and public transcriptome, single-cell transcriptome, and spatial transcriptome databases to profile the molecular atlas of the tumor microenvironments of MC, AC, and normal colon tissues. By exploring the general and specific molecular features of AC and MC, we found that AC was immune-active but exposed to a hypoxic microenvironment. MC cells could protect against DNA damage, and the microenvironment was unfavorable to leukocyte transendothelial migration. We identified several potential molecular and cellular targets of AC and MC for future research. We also highlighted that the major difference between AC and MC was not the variety of cell types and functions but possibly cell interactions. Stromal and epithelial cell interactions play important roles in both MC and AC, but different regulatory pathways were involved.

Multi compartmental 3D breast cancer disease model–recapitulating tumor complexity in in-vitro

Breast cancer is the most common ailment among women. In 2020, it had the highest incidence of any type of cancer. Many Phase II and III anti-cancer drugs fail due to efficacy, durability, and side effects. Thus, accelerated drug screening models must be accurate. In-vivo models have been used for a long time, but delays, inconsistent results, and a greater sense of responsibility among scientists toward wildlife have led to the search for in-vitro alternatives. Stromal components support breast cancer growth and survival. Multi-compartment Transwell models may be handy instruments. Co-culturing breast cancer cells with endothelium and fibroblasts improves modelling. The extracellular matrix (ECM) supports native 3D hydrogels in natural and polymeric forms. 3D Transwell cultured tumor spheroids mimicked in-vivo pathological conditions. Tumor invasion, migration, Trans-endothelial migration, angiogenesis, and spread are studied using comprehensive models. Transwell models can create a cancer niche and conduct high-throughput drug screening, promising future applications. Our comprehensive shows how 3D in-vitro multi compartmental models may be useful in producing breast cancer stroma in Transwell culture.

Everybody needs good neighbours: the progressive DCIS microenvironment

Ductal carcinoma in situ (DCIS) is a pre-invasive form of breast cancer where neoplastic luminal cells are confined to the ductal tree. While as many as 70% of DCIS cases will remain indolent, most women are treated with surgery, often combined with endocrine and radiotherapies. Overtreatment is therefore a major issue, demanding new methods to stratify patients. Somewhat paradoxically, the neoplastic cells in DCIS are genetically comparable to those in invasive disease, suggesting the tumour microenvironment is the driving force for progression. Clinical and mechanistic studies highlight the complex DCIS microenvironment, with multiple cell types competing to regulate progression. Here, we examine recent studies detailing distinct aspects of the DCIS microenvironment and discuss how these may inform more effective care.

Fibroblasts as Turned Agents in Cancer Progression

Differentiated epithelial cells reside in the homeostatic microenvironment of the native organ stroma. The stroma supports their normal function, their G0 differentiated state, and their expansion/contraction through the various stages of the life cycle and physiologic functions of the host. When malignant transformation begins, the microenvironment tries to suppress and eliminate the transformed cells, while cancer cells, in turn, try to resist these suppressive efforts. The tumor microenvironment encompasses a large variety of cell types recruited by the tumor to perform different functions, among which fibroblasts are the most abundant. The dynamics of the mutual relationship change as the sides undertake an epic battle for control of the other. In the process, the cancer "wounds" the microenvironment through a variety of mechanisms and attracts distant mesenchymal stem cells to change their function from one attempting to suppress the cancer, to one that supports its growth, survival, and metastasis. Analogous reciprocal interactions occur as well between disseminated cancer cells and the metastatic microenvironment, where the microenvironment attempts to eliminate cancer cells or suppress their proliferation. However, the altered microenvironmental cells acquire novel characteristics that support malignant progression. Investigations have attempted to use these traits as targets of novel therapeutic approaches.

TGFβ-mediated MMP13 secretion drives myoepithelial cell dependent breast cancer progression

Ductal carcinoma in situ (DCIS) is a non-obligate precursor of invasive breast cancer. Virtually all women with DCIS are treated, despite evidence suggesting up to half would remain with stable, non-threatening, disease. Overtreatment thus presents a pressing issue in DCIS management. To understand the role of the normally tumour suppressive myoepithelial cell in disease progression we present a 3D in vitro model incorporating both luminal and myoepithelial cells in physiomimetic conditions. We demonstrate that DCIS-associated myoepithelial cells promote striking myoepithelial-led invasion of luminal cells, mediated by the collagenase MMP13 through a non-canonical TGFβ - EP300 pathway. In vivo, MMP13 expression is associated with stromal invasion in a murine model of DCIS progression and is elevated in myoepithelial cells of clinical high-grade DCIS cases. Our data identify a key role for myoepithelial-derived MMP13 in facilitating DCIS progression and point the way towards a robust marker for risk stratification in DCIS patients.

Mimicking Tumor Cell Heterogeneity of Colorectal Cancer in a Patient-derived Organoid-Fibroblast Model

BACKGROUND & AIMS

Patient-derived organoid cancer models are generated from epithelial tumor cells and reflect tumor characteristics. However, they lack the complexity of the tumor microenvironment, which is a key driver of tumorigenesis and therapy response. Here, we developed a colorectal cancer organoid model that incorporates matched epithelial cells and stromal fibroblasts.

METHODS

Primary fibroblasts and tumor cells were isolated from colorectal cancer specimens. Fibroblasts were characterized for their proteome, secretome, and gene expression signatures. Fibroblast/organoid co-cultures were analyzed by immunohistochemistry and compared with their tissue of origin, as well as on gene expression levels compared with standard organoid models. Bioinformatics deconvolution was used to calculate cellular proportions of cell subsets in organoids based on single-cell RNA sequencing data.

RESULTS

Normal primary fibroblasts, isolated from tumor adjacent tissue, and cancer associated fibroblasts retained their molecular characteristics in vitro, including higher motility of cancer associated compared with normal fibroblasts. Importantly, both cancer-associated fibroblasts and normal fibroblasts supported cancer cell proliferation in 3D co-cultures, without the addition of classical niche factors. Organoids grown together with fibroblasts displayed a larger cellular heterogeneity of tumor cells compared with mono-cultures and closely resembled the in vivo tumor morphology. Additionally, we observed a mutual crosstalk between tumor cells and fibroblasts in the co-cultures. This was manifested by considerably deregulated pathways such as cell-cell communication and extracellular matrix remodeling in the organoids. Thrombospondin-1 was identified as a critical factor for fibroblast invasiveness.

CONCLUSION

We developed a physiological tumor/stroma model, which will be vital as a personalized tumor model to study disease mechanisms and therapy response in colorectal cancer.

Rational synthesis of carbon dots with phosphate ester group for direct mapping of endogenous alkaline phosphatase and polarity monitoring in living cells

Carbon dots (CDs) have been extensively employed in biomolecule imaging. However, the imaging of biological enzymes with CDs has not been reported, which greatly limits their application in biological imaging. Herein, for the first time, a new type of fluorescent CDs is elaborately designed to realize the direct mapping of alkaline phosphatase (ALP) in cells. The obtained phosphorus and nitrogen co-doped CDs (P, N-CDs) generate specific structures including xanthene oxide and phosphate ester, thereby enabling P, N-CDs to be exclusively cleaved by ALP without auxiliary media. The fluorescence intensity of P, N-CDs can be specifically turned on in the presence of ALP, making them powerful probes for sensitive sensing of ALP activity with a detection limit of 1.27 U·L^-1. Meanwhile, P, N-CDs possessing electron deficiency structure fulfill sensitive responding to polarity variations. The excellent photo-bleaching resistance and biocompatibility of the P, N-CDs are taken for directly mapping the intracellular endogenous ALP via turned-on fluorescence imaging, as well as real-time monitoring the polarity fluctuation in cells through ratiometric fluorescence imaging. The present work offers a new way to design and synthesize functional CDs for direct imaging of intracellular enzymes.

A role for fibroblast-derived SASP factors in the activation of pyroptotic cell death in mammary epithelial cells

In normal tissue homeostasis, bidirectional communication between different cell types can shape numerous biological outcomes. Many studies have documented instances of reciprocal communication between fibroblasts and cancer cells that functionally change cancer cell behavior. However, less is known about how these heterotypic interactions shape epithelial cell function in the absence of oncogenic transformation. Furthermore, fibroblasts are prone to undergo senescence, which is typified by an irreversible cell cycle arrest. Senescent fibroblasts are also known to secrete various cytokines into the extracellular space; a phenomenon that is termed the senescence-associated secretory phenotype (SASP). While the role of fibroblast derived SASP factors on cancer cells has been well studied, the impact of these factors on normal epithelial cells remains poorly understood. We discovered that treatment of normal mammary epithelial cells with conditioned media (CM) from senescent fibroblasts (SASP CM) results in a caspase-dependent cell death. This capacity of SASP CM to cause cell death is maintained across multiple senescence-inducing stimuli. However, the activation of oncogenic signaling in mammary epithelial cells mitigates the ability of SASP CM to induce cell death. Despite the reliance of this cell death on caspase activation, we discovered that SASP CM does not cause cell death by the extrinsic or intrinsic apoptotic pathway. Instead, these cells die by an NLRP3, caspase-1, and gasdermin D (GSDMD)-dependent induction of pyroptosis. Taken together, our findings reveal that senescent fibroblasts can cause pyroptosis in neighboring mammary epithelial cells, which has implications for therapeutic strategies that perturb the behavior of senescent cells.

Tumour necrosis factor stimulated gene 6 intrinsically regulates PD-L1 expressions in breast cancer cells, leading to modulation of tumour microenvironment

Recent studies have shown that tumour cells express tumour necrosis factor-inducible gene 6 (TSG-6) and its protein, which is known to play a key role in regulating excessive immune responses and proliferation and growth of mesenchymal stem cells (MSCs). It has not been confirmed whether the inhibition of TSG-6 for tumour cells can suppress tumour cell growth and regulate the activation of immune cells in the tumour microenvironment (TME). TSG-6-specific small interfering RNA was transfected into canine and human breast cancer cells (CIPp, CIPm and BT-20). TSG-6-down-regulated (siTSG-6) cells showed decreased cell proliferation, migration, and invasion abilities. Decreased mRNA expressions of NF-κB, STAT3 and Sox2, confirming that TSG-6 is an upper factor governing tumour growth and metastasis. Notably, siTSG-6 cells showed significantly decreased expression levels of CD44 and PD-L1. Direct and indirect co-culture of canine peripheral blood mononuclear cells (cPBMCs) and the siTSG-6 cells showed significant activation in M1 type macrophages and cytotoxic T cells. They also showed a tendency to decrease in the expression of CTLA-4 and increase in the expression of PD-1. In conclusion, this study suggests that the down-regulation of TSG-6 in breast cancer cells could not only suppress tumour growth and metastasis, and but also regulate TME. Since modulation of immune checkpoint proteins occurs in both tumour cells and immune cells, inhibiting TSG-6 and its protein within the TME could be novel therapeutic target for anticancer treatment.

Driving role of head and neck cancer cell secretome on the invasion of stromal fibroblasts: Mechanistic insights by phosphoproteomics

BACKGROUND

Cancer-associated fibroblasts (CAFs) are major players in tumor-stroma communication, and participate in several cancer hallmarks to drive tumor progression and metastatic dissemination. This study investigates the driving effects of tumor-secreted factors on CAF biology, with the ultimate goal of identifying effective therapeutic targets/strategies for head and neck squamous cell carcinomas (HNSCC).

METHODS

Functionally, conditioned media (CM) from different HNSCC-derived cell lines and normal keratinocytes (Kc) were tested on the growth and invasion of populations of primary CAFs and normal fibroblasts (NFs) using 3D invasion assays in collagen matrices. The changes in MMPs expression were evaluated by RT-qPCR and kinase enrichment was analyzed using mass spectrometry phosphoproteomics.

RESULTS

Our results consistently demonstrate that HNSCC-secreted factors (but not Kc CM) specifically and robustly promoted pro-invasive properties in both CAFs and NFs, thereby reflecting the plasticity of fibroblast subtypes. Concomitantly, HNSCC-secreted factors massively increased metalloproteinases levels in CAFs and NFs. By contrast, HNSCC CM and Kc CM exhibited comparable growth-promoting effects on stromal fibroblasts. Mechanistically, phosphoproteomic analysis predominantly revealed phosphorylation changes in fibroblasts upon treatment with HNSCC CM, and various promising kinases were identified: MKK7, MKK4, ASK1, RAF1, BRAF, ARAF, COT, PDK1, RSK2 and AKT1. Interestingly, pharmacologic inhibition of RAF1/BRAF using sorafenib emerged as the most effective drug to block tumor-promoted fibroblast invasion without affecting fibroblast viability CONCLUSIONS: Our findings demonstrate that HNSCC-secreted factors specifically fine tune the invasive potential of stromal fibroblasts, thereby generating tumor-driven pro-invasive niches, which in turn to ultimately facilitate cancer cell dissemination. Furthermore, the RAF/BRAF inhibitor sorafenib was identified as a promising candidate to effectively target the onset of pro-invasive clusters of stromal fibroblasts in the HNSCC microenvironment.

Cysteine Cathepsins in Breast Cancer: Promising Targets for Fluorescence-Guided Surgery

The majority of breast cancer patients is treated with breast-conserving surgery (BCS) combined with adjuvant radiation therapy. Up to 40% of patients has a tumor-positive resection margin after BCS, which necessitates re-resection or additional boost radiation. Cathepsin-targeted near-infrared fluorescence imaging during BCS could be used to detect residual cancer in the surgical cavity and guide additional resection, thereby preventing tumor-positive resection margins and associated mutilating treatments. The cysteine cathepsins are a family of proteases that play a major role in normal cellular physiology and neoplastic transformation. In breast cancer, the increased enzymatic activity and aberrant localization of many of the cysteine cathepsins drive tumor progression, proliferation, invasion, and metastasis. The upregulation of cysteine cathepsins in breast cancer cells indicates their potential as a target for intraoperative fluorescence imaging. This review provides a summary of the current knowledge on the role and expression of the most important cysteine cathepsins in breast cancer to better understand their potential as a target for fluorescence-guided surgery (FGS). In addition, it gives an overview of the cathepsin-targeted fluorescent probes that have been investigated preclinically and in breast cancer patients. The current review underscores that cysteine cathepsins are highly suitable molecular targets for FGS because of favorable expression and activity patterns in virtually all breast cancer subtypes. This is confirmed by cathepsin-targeted fluorescent probes that have been shown to facilitate in vivo breast cancer visualization and tumor resection in mouse models and breast cancer patients. These findings indicate that cathepsin-targeted FGS has potential to improve treatment outcomes in breast cancer patients.

Fibroblast Growth Factor-2 and the Invasive Potential in Urothelial Malignancies of the Bladder

Introduction Urothelial carcinomas represent a distinct group of malignancies with a high recurrence potential. Multiple studies have established a set of interactions between the tumor cells of urothelial neoplasms and the extracellular matrix regarding invasion and tumor progression. In the present study, we evaluated the expression of fibroblast growth factor-2 (FGF2) in early-stage urothelial carcinomas of the urinary bladder (pTa and pT1) regarding the invasive potential of these tumors. Materials and methods A retrospective non-clinical approach was utilized for the study. Tumor tissue sections used for the initial diagnosis were stained by immunohistochemical means with an anti-FGF2 antibody and the expression within the extracellular matrix was evaluated using a histo-score (h-score). Statistical parameters regarding tumor invasion, FGF2 expression pattern and levels, patient demographic characteristics, and disease recurrence were analyzed for significance. Results A total of 163 cases were analyzed, with an h-score of 110 determined as the optimal cut-off value for invasive potential regarding FGF2 expression, with a sensitivity of 75.4% and a specificity of 78.9%. No statistical correlation was established between the demographic profile of the patients and the occurrence of disease recurrence. Conclusion Based on our results, the study of tumor-extracellular matrix interactions in regards to FGF2 expression is a promising field, at least in urothelial malignancies of the urinary bladder, in regards to tumor invasive potential, while it remains unestablished how these interactions affect metastatic potential.

Re-evaluation of the myoepithelial cells roles in the breast cancer progression

Over the past decades, luminal epithelial cell lineage has gained considerable attraction as the functionally milk-secreting units and as the most fruitful acreage for breast cancer launching. Recognition of the effective involvement of the myoepithelial cells in mammary gland development and in hampering tumorigenesis has renewed the interest in investigating the biological roles of this second main mammary lineage. The human breast is made up of an extensively branching ductal system intervening by copious lobular units. The ductal system is coated by a chain of luminal epithelial cells (LECs) situated on a layer of myoepithelial cells (MECs) and encompassed by a distinguished basement membrane. Ductal contractility during lactation is a well-known function delivered by the MECs however this is not the only assignment mediated by these cellular populations. It has been well appreciated that the MECs exhibit a natural paracrine power in defeating cancer development and advancement. MECs were found to express numerous proteinase inhibitors, anti-angiogenic factors, and tumour suppressors proteins. Additionally, MECs contributed effectively to maintaining the right luminal cells' polarization and further separating them from the adjacent stroma by making an integrated fence. Indeed, disruption of the MECs layer was reported to facilitate the invasion of the cancer cells to the surrounding stroma. Nonetheless, MECs were also found to exhibit cancer-promoting effects and provoke tumour invasion and dissemination by displaying distinct cancer chemokines. Herein in this review, we aimed to address the roles delivered by MECs in breast cancer progression and decipher the molecular mechanisms regulating proper MECs' physiology, integrity, and terminal differentiation.