Inverse expression of cystein-rich 61 (Cyr61/CCN1) and connective tissue growth factor (CTGF/CCN2) in borderline tumors and carcinomas of the ovary

The dynamic interplay between melanoma cells and CAFs: Implications drug resistance and immune evasion and possible therapeutics

Melanoma, a malignancy of varying prognoses across primary sites (cutaneous, ocular, and mucosal), typically displays peculiar treatment challenges in metastatic and refractory settings. Cancer-associated fibroblasts (CAFs) have long been recognized as pivotal components within melanoma's tumor microenvironment (TME), originating from various sources and manifesting considerable heterogeneity. These cells actively produce extracellular matrix (ECM), induce angiogenesis, provide metabolic support, contribute to drug resistance, and feed tumor progression and metastasis. Among the many growth factors and cytokines they secrete, including TGF-β and IL-6, they aid in anti-tumor immunity by recruiting immunosuppressive cells and inhibiting cytotoxic T-cell activity, contributing to immune evasion. These dynamic cells sculpt the tumor's niche, allowing cancer cells to survive and proliferate, and their existence is widely correlated with poor prognosis. Taking a cue from the previously established groundwork of how the surroundings heavily influence tumor development, this review attempts to profile the intricate interaction of melanoma cells with the CAFs, the ECM, and signaling molecules. We explore different subtypes of CAFs, their origins, and how they have evolved in their pro-tumorigenic roles in melanoma. Additionally, we review recent advancements in the therapeutic arsenal targeting CAFs to achieve a more effective treatment response. By detailing the specific roles played by different CAFs subtypes in the modulation of immuno-responses and treatment outcomes, this review will further provide insights into the targeted therapy to disrupt CAFs-mediated tumor support in melanoma.

Blocking CCN2 Reduces Established Palmar Neuromuscular Fibrosis and Improves Function Following Repetitive Overuse Injury

The matricellular protein cell communication factor 2/connective tissue growth factor (CCN2/CTGF) is critical to development of neuromuscular fibrosis. Here, we tested whether anti-CCN2 antibody treatment will reduce established forepaw fibro-degenerative changes and improve function in a rat model of overuse injury. Adult female rats performed a high repetition high force (HRHF) task for 18 weeks. Tissues were collected from one subset after 18 wks (HRHF-Untreated). Two subsets were provided 6 wks of rest with concurrent treatment with anti-CCN2 (HRHF-Rest/anti-CCN2) or IgG (HRHF-Rest/IgG). Results were compared to IgG-treated Controls. Forepaw muscle fibrosis, neural fibrosis and entheseal damage were increased in HRHF-Untreated rats, compared to Controls, and changes were ameliorated in HRHF-Rest/anti-CCN2 rats. Anti-CCN2 treatment also reduced phosphorylated-β-catenin (pro-fibrotic protein) in muscles and distal bone/entheses complex, and increased CCN3 (anti-fibrotic) in the same tissues, compared to HRHF-Untreated rats. Grip strength declines and mechanical sensitivity observed in HRHF-Untreated improved with rest; grip strength improved further in HRHF-Rest/anti-CCN2. Grip strength declines correlated with muscle fibrosis, entheseal damage, extraneural fibrosis, and decreased nerve conduction velocity, while enhanced mechanical sensitivity (a pain-related behavior) correlated with extraneural fibrosis. These studies demonstrate that blocking CCN2 signaling reduces established forepaw neuromuscular fibrosis and entheseal damage, which improves forepaw function, following overuse injury.

Targeting CTGF in Cancer: An Emerging Therapeutic Opportunity

Despite the dramatic advances in cancer research over the decades, effective therapeutic strategies are still urgently needed. Increasing evidence indicates that connective tissue growth factor (CTGF), a multifunctional signaling modulator, promotes cancer initiation, progression, and metastasis by regulating cell proliferation, migration, invasion, drug resistance, and epithelial-mesenchymal transition (EMT). CTGF is also involved in the tumor microenvironment in most of the nodes, including angiogenesis, inflammation, and cancer-associated fibroblast (CAF) activation. In this review, we comprehensively discuss the expression of CTGF and its regulation, oncogenic role, clinical relevance, targeting strategies, and therapeutic agents. Herein, we propose that CTGF is a promising cancer therapeutic target that could potentially improve the clinical outcomes of cancer patients.

Blocking CTGF/CCN2 reduces established skeletal muscle fibrosis in a rat model of overuse injury

Tissue fibrosis is a hallmark of overuse musculoskeletal injuries and contributes to functional declines. We tested whether inhibition of CCN2 (cellular communication network factor 2, previously known as connective tissue growth factor, CTGF) using a specific antibody (termed FG‐3019 or pamrevlumab) reduces established overuse‐induced muscle fibrosis in a clinically relevant rodent model of upper extremity overuse injury. Young adult rats performed a high repetition high force (HRHF) reaching and lever‐pulling task for 18 weeks, after first being shaped for 6 weeks to learn this operant task. Rats were then euthanized (HRHF‐Untreated), or rested and treated for 6 weeks with FG‐3019 (HRHF‐Rest/FG‐3019) or a human IgG as a vehicle control (HRHF‐Rest/IgG). HRHF‐Untreated and HRHF‐Rest/IgG rats had higher muscle levels of several fibrosis‐related proteins (TGFβ1, CCN2, collagen types I and III, and FGF2), and higher muscle numbers of alpha SMA and pERK immunopositive cells, compared to control rats. Each of these fibrogenic changes was restored to control levels by the blocking of CCN2 signaling in HRHF‐Rest/FG‐3019 rats, as were HRHF task‐induced increases in serum CCN2 and pro‐collagen I intact N‐terminal protein. Levels of cleaved CCN3, an antifibrotic protein, were lowered in HRHF‐Untreated and HRHF‐Rest/IgG rats, compared to control rats, yet elevated back to control levels in HRHF‐Rest/FG‐3019 rats. Significant grip strength declines observed in HRHF‐Untreated and HRHF‐Rest/IgG rats, were restored to control levels in HRHF‐Rest/FG‐3019 rats. These results are highly encouraging for use of FG‐3019 for therapeutic treatment of persistent skeletal muscle fibrosis, such as those induced with chronic overuse.

Biological functions and role of CCN1/Cyr61 in embryogenesis and tumorigenesis in the female reproductive system (Review)

Cysteine-rich angiogenic inducer 61 (CCN1/Cyr61) is a prompt response transcription product activated by growth factors. As a member of the CCN family, it mediates cell survival, proliferation, differentiation, migration, adhesion and synthesis of the extracellular matrix by binding directly to the integrins and heparin sulfate proteoglycans or activating multiple signaling transduction pathways. It has previously been demonstrated that CCN1/Cyr61 exhibits an important role in the female reproductive system during embryogenesis and tumorigenesis. However, the functions of CCN1/Cyr61 in the female reproductive system have not been systematically investigated, therefore, the primary aim of the present review is to introduce the role and function of CCN1/Cyr61 in the female reproductive system. The current review presents the molecular structure and biological function of CCN1/Cyr61 and provides detailed data on its expression pattern and contribution to the female reproductive system, including the role in embryogenesis and tumorigenesis.

Connective tissue growth factor as a novel therapeutic target in high grade serous ovarian cancer

Ovarian cancer is the most common cause of death among women with gynecologic cancer. We examined molecular profiles of fibroblasts from normal ovary and high-grade serous ovarian tumors to identify novel therapeutic targets involved in tumor progression. We identified 2,300 genes that are significantly differentially expressed in tumor-associated fibroblasts. Fibroblast expression of one of these genes, connective tissue growth factor (CTGF), was confirmed by immunohistochemistry. CTGF protein expression in ovarian tumor fibroblasts significantly correlated with gene expression levels. CTGF is a secreted component of the tumor microenvironment and is being pursued as a therapeutic target in pancreatic cancer. We examined its effect in in vitro and ex vivo ovarian cancer models, and examined associations between CTGF expression and clinico-pathologic characteristics in patients. CTGF promotes migration and peritoneal adhesion of ovarian cancer cells. These effects are abrogated by FG-3019, a human monoclonal antibody against CTGF, currently under clinical investigation as a therapeutic agent. Immunohistochemical analyses of high-grade serous ovarian tumors reveal that the highest level of tumor stromal CTGF expression was correlated with the poorest prognosis. Our findings identify CTGF as a promoter of peritoneal adhesion, likely to mediate metastasis, and a potential therapeutic target in high-grade serous ovarian cancer. These results warrant further studies into the therapeutic efficacy of FG-3019 in high-grade serous ovarian cancer.

CCN family of proteins: critical modulators of the tumor cell microenvironment

The CCN family of proteins consisting of CCN1 (Cyr61), CCN2 (CTGF), CCN3 (NOV), CCN4 (WISP-1), CCN5 (WISP-2) and CCN6 (WISP-3) are considered matricellular proteins operating essentially in the extracellular microenvironment between cells. Evidence has also been gradually building since their first discovery of additional intracellular roles although the major activity is triggered at the cell membrane. The proteins consist of 4 motifs, a signal peptide (for secretion} followed consecutively by the IGFBP, VWC, TSP1 and CT (C-terminal cysteine knot domain) motifs, which signify their potential binding partners and functional connections to a variety of key regulators of physiological processes. With respect to cancer it is now clear that, whereas certain members can facilitate tumor behavior and progression, others can competitively counter the process. It is therefore clear that the net outcome of biological interactions in the matrix and what gets signaled or inhibited can be a function of the interplay of these CCN 1-6 proteins. Because the CCN proteins further interact with other key proteins, like growth factors in the matrix, the balance is not only important but can vary dynamically with the physiological states of tumor cells and the surrounding normal cells. The tumor niche with its many cell players has surfaced as a critical determinant of tumor behavior, invasiveness, and metastasis. It is in this context that CCN proteins should be investigated with the potential of being recognized and validated for future therapeutic approaches.