The role of collagen triple helix repeat containing 1 (CTHRC1) in cancer development and progression.

INTRODUCTION: Collagen triple helix repeat containing 1 (CTHRC1) is a protein that has been implicated in pro-migratory pathways, arterial tissue-repair processes, and inhibition of collagen deposition via the regulation of multiple signaling cascades. Studies have also demonstrated an upregulation of CTHRC1 in multiple cancers where it has been linked to enhanced proliferation, invasion, and metastasis. However, the understanding of the exact role and mechanisms of CTHRC1 in cancer is far from complete. AREAS COVERED: This review focuses on analyzing the role of CTHRC1 in cancer as well as its associations with clinicopathologies and cancer-related processes and signaling. We have also summarized the available literature information regarding the role of CTHRC1 in tumor microenvironment and immune signaling. Finally, we have discussed the mechanisms associated with CTHRC1 regulations, and opportunities and challenges regarding the development of CTHRC1 as a potential target for cancer management. EXPERT OPINION: CTHRC1 is a multifaceted protein with critical roles in cancer progression and other pathological conditions. Its association with lower overall survival in various cancers, and impact on the tumor immune microenvironment make it an intriguing target for further research and potential therapeutic interventions in cancer.

The fusion of light and immunity: Advancements in photoimmunotherapy for melanoma.

Metastatic melanoma is an aggressive skin cancer with high mortality and recurrence rates. Despite the clinical success of recent immunotherapy approaches, prevailing resistance rates necessitate the continued development of novel therapeutic options. Photoimmunotherapy (PIT) is emerging as a promising immunotherapy strategy that uses photodynamic therapy (PDT) to unleash systemic immune responses against tumor sites while maintaining the superior tumor-specificity and minimally invasive nature of traditional PDT. In this review, we discuss recent advances in PIT and strategies for the management of melanoma using PIT. PIT can strongly induce immunogenic cell death, inviting the concomitant application of immune checkpoint blockade or adoptive cell therapies. PIT can also be leveraged to selectively remove the suppressive immune populations associated with immunotherapy resistance. The modular nature of PIT therapy design combined with the potential for patient-specific antigen selection or drug co-delivery makes PIT an alluring option for future personalized melanoma care.

Immune escape and metastasis mechanisms in melanoma: breaking down the dichotomy.

Melanoma is one of the most lethal neoplasms of the skin. Despite the revolutionary introduction of immune checkpoint inhibitors, metastatic spread, and recurrence remain critical problems in resistant cases. Melanoma employs a multitude of mechanisms to subvert the immune system and successfully metastasize to distant organs. Concerningly, recent research also shows that tumor cells can disseminate early during melanoma progression and enter dormant states, eventually leading to metastases at a future time. Immune escape and metastasis have previously been viewed as separate phenomena; however, accumulating evidence is breaking down this dichotomy. Recent research into the progressive mechanisms of melanoma provides evidence that dedifferentiation similar to classical epithelial to mesenchymal transition (EMT), genes involved in neural crest stem cell maintenance, and hypoxia/acidosis, are important factors simultaneously involved in immune escape and metastasis. The likeness between EMT and early dissemination, and differences, also become apparent in these contexts. Detailed knowledge of the mechanisms behind "dual drivers" simultaneously promoting metastatically inclined and immunosuppressive environments can yield novel strategies effective in disabling multiple facets of melanoma progression. Furthermore, understanding progression through these drivers may provide insight towards novel treatments capable of preventing recurrence arising from dormant dissemination or improving immunotherapy outcomes.

Role of PLK1/NUMB/NOTCH in epithelial-mesenchymal transition in human melanoma.

Polo-like kinase 1 (PLK1), a serine/threonine kinase, is overexpressed in melanoma and its expression has been associated with poor disease prognosis. PLK1 has been shown to interact with NUMB, a NOTCH antagonist. However, the exact role of PLK1, NUMB, and NOTCH signaling in epithelial-mesenchymal transition (EMT) in melanoma progression is unclear. In this study, Affymetrix microarray analysis was performed to determine differentially expressed genes following shRNA-mediated knockdown of PLK1 in human melanoma cells that showed significant modulations in EMT and metastasis-related genes. Using multiple PLK1-modulated melanoma cell lines, we found that PLK1 is involved in the regulation of cell migration, invasion, and EMT via its kinase activity and NOTCH activation. In vitro kinase assay and mass spectrometry analysis demonstrated a previously unknown PLK1 phosphorylation site (Ser413) on NUMB. Overexpression of non-phosphorylatable (S413A) and phosphomimetic (S413D) mutants of NUMB in melanoma cells implicated the involvement of NUMB-S413 phosphorylation in cell migration and invasion, which was independent of NOTCH activation. To determine the clinical relevance of these findings, immunohistochemistry was performed using melanoma tissue microarray, which indicated a strong positive correlation between PLK1 and N-cadherin, a protein required for successful EMT. These findings were supported by TCGA analysis, where expression of high PLK1 with low NUMB or high NOTCH or N-cadherin showed a significant decrease in survival of melanoma patients. Overall, these results suggest a potential role of PLK1 in EMT, migration, and invasion of melanoma cells. Our findings support the therapeutic targeting of PLK1, NUMB, and NOTCH for melanoma management.

Trichloroisocyanuric Acid, A Swimming Pool Disinfectant: New Developments and Role in UV-Induced Skin Inflammation†.

This article is a highlight of the paper by Snell et al. in the current issue of Photochemistry and Photobiology (Snell et al. Photochem. Photobiol. 2022). The authors utilized an organotypic human skin model and transgenic SKH-1 mice to determine the oxidative stress response induced by topical treatment of trichloroisocyanuric acid (TCIC), a common disinfectant used in swimming pool. Additionally, they determined molecular mechanisms associated with topical TCIC pretreatment followed by ultraviolet (UV) radiation exposure. This work provides the first example that cutaneous delivery of TCIC significantly increases UV-induced skin inflammation, suggesting a previously unidentified potential of TCIC. If translatable to human skin, these findings could be important for human skin health implications.

Association of CARD14 Single-Nucleotide Polymorphisms with Psoriasis.

Psoriasis is an immune-mediated chronic and painful disease characterized by red raised patches of inflamed skin that may have desquamation, silvery-white scales, itching and cracks. The susceptibility of developing psoriasis depends on multiple factors, with a complex interplay between genetic and environmental factors. Studies have suggested an association between autosomal dominant CARD14 (caspase recruitment domain-containing protein 14) gain-of-function mutations with the pathophysiology of psoriasis. In this study, non-synonymous single-nucleotide polymorphisms (nsSNPs) of CARD14 gene were assessed to determine their association with psoriasis in Pakistani population. A total of 123 subjects (63 patients with psoriasis and 60 normal controls) were included in this study. DNA was extracted from blood, and PCR analysis was performed followed by Sanger sequencing for 18 CARD14 specific nsSNPs (14 previously reported and the 4 most pathogenic nsSNPs identified using bioinformatics analysis). Among the 18 tested SNPs, only 2 nsSNP, rs2066965 (R547S) and rs34367357 (V585I), were found to be associated with psoriasis. Furthermore, rs2066965 heterozygous genotype was found to be more prevalent in patients with joint pain. Additionally, the 3D structure of CARD14 protein was predicted using alpha-fold2. NMSim web server was used to perform coarse grind simulations of wild-type CARD14 and two mutated structures. R547S increases protein flexibility, whereas V353I is shown to promote CARD14-induced NF-kappa B activation. This study confirms the association between two CARD14 nsSNPs, rs2066965 and rs34367357 with psoriasis in a Pakistani population, and could be helpful in identifying the role of CARD14 gene variants as potential genetic markers in patients with psoriasis.

Mechanisms of Immunotherapy Resistance in Cutaneous Melanoma: Recognizing a Shapeshifter.

Melanoma is one of the seven most common cancers in the United States, and its incidence is still increasing. Since 2011, developments in targeted therapies and immunotherapies have been essential for significantly improving overall survival rates. Prior to the advent of targeted and immunotherapies, metastatic melanoma was considered a death sentence, with less than 5% of patients surviving more than 5 years. With the implementation of immunotherapies, approximately half of patients with metastatic melanoma now survive more than 5 years. Unfortunately, this also means that half of the patients with melanoma do not respond to current therapies and live less than 5 years after diagnosis. One major factor that contributes to lower response in this population is acquired or primary resistance to immunotherapies via tumor immune evasion. To improve the overall survival of melanoma patients new treatment strategies must be designed to minimize the risk of acquired resistance and overcome existing primary resistance. In recent years, many advances have been made in identifying and understanding the pathways that contribute to tumor immune evasion throughout the course of immunotherapy treatment. In addition, results from clinical trials focusing on treating patients with immunotherapy-resistant melanoma have reported some initial findings. In this review, we summarize important mechanisms that drive resistance to immunotherapies in patients with cutaneous melanoma. We have focused on tumor intrinsic characteristics of resistance, altered immune function, and systemic factors that contribute to immunotherapy resistance in melanoma. Exploring these pathways will hopefully yield novel strategies to prevent acquired resistance and overcome existing resistance to immunotherapy treatment in patients with cutaneous melanoma.

PLK1 inhibition-based combination therapies for cancer management.

Polo-like kinase I (PLK1), a cell cycle regulating kinase, has been shown to have oncogenic function in several cancers. Although PLK1 inhibitors, such as BI2536, BI6727 (volasertib) and NMS-1286937 (onvansertib) are generally well-tolerated with a favorable pharmacokinetic profile, clinical successes are limited due to partial responses in cancer patients, especially those in advanced stages. Recently, combination therapies targeting multiple pathways are being tested for cancer management. In this review, we first discuss structure and function of PLK1, role of PLK1 in cancers, PLK1 specific inhibitors, and advantages of using combination therapy versus monotherapy followed by a critical account on PLK1-based combination therapies in cancer treatments, especially highlighting recent advancements and challenges. PLK1 inhibitors in combination with chemotherapy drugs and targeted small molecules have shown superior effects against cancer both in vitro and in vivo. PLK1-based combination therapies have shown increased apoptosis, disrupted cell cycle, and potential to overcome resistance in cancer cells/tissues over monotherapies. Further, with successes in preclinical experiments, researchers are validating such approaches in clinical trials. Although PLK1-based combination therapies have achieved initial success in clinical studies, there are examples where they have failed to improve patient survival. Therefore, further research is needed to identify and validate novel biologically informed co-targets for PLK1-based combinatorial therapies. Employing a network-based analysis, we identified potential PLK1 co-targets that could be examined further. In addition, understanding the mechanisms of synergism between PLK1 inhibitors and other agents may lead to a better approach on which agents to pair with PLK1 inhibition for optimum cancer treatment.

BRAF Inhibitors in Melanoma Management: When Friends Become Foes.

The BRAF inhibitor (BRAFi) vemurafenib improves survival of patients with melanoma with BRAFV600E mutations. However, effects of sustained BRAFis on BRAFi-resistant melanomas with dual mutations in BRAF and NRAS are not well characterized. Jandova and Wondrak (2021) report that vemurafenib selectively enhances expression of genes involved in the epithelial-to-mesenchymal transition in BRAFV600E/NRASQ61K melanoma cells, paradoxically promoting tumor growth and metastasis in mice. This preclinical study provides compelling reasons to be cautious in the use of BRAFis in patients with NRAS-driven melanoma.

Antimelanoma Effects of Concomitant Inhibition of SIRT1 and SIRT3 in BrafV600E/PtenNULL Mice.

Novel therapeutic strategies are required for the effective and lasting treatment of metastatic melanoma, one of the deadliest skin malignancies. In this study, we determined the antimelanoma efficacy of 4'-bromo-resveratrol (4'-BR), which is a small-molecule dual inhibitor of SIRT1 and SIRT3, in a BrafV600E/PtenNULL mouse model that recapitulates human disease, including metastases. Tumors were induced by topical application of 4-hydroxy-tamoxifen on shaved backs of mice aged 10 weeks, and the effects of 4'-BR (5‒30 mg/kg of body weight, intraperitoneally, 3 days per week for 5 weeks) were assessed on melanoma development and progression. We found that 4'-BR at a dose of 30 mg/kg significantly reduced the size and volume of primary melanoma tumors as well as lung metastasis with no adverse effects. Furthermore, mechanistic studies on tumors showed significant modulation in the markers of proliferation, survival, and melanoma progression. Because SIRT1 and SIRT3 are linked to immunomodulation, we performed differential gene expression analysis using a PanCancer Immune Profiling Panel (770 genes). Our data showed that 4'-BR significantly downregulated the genes related to metastasis promotion, chemokine/cytokine regulation, and innate/adaptive immune functions. Overall, inhibition of SIRT1 and SIRT3 by 4'-BR is a promising antimelanoma therapy with antimetastatic and immunomodulatory activities warranting further detailed studies, including clinical investigations.

Protective effects of dietary grape against atopic dermatitis-like skin lesions in NC/NgaTndCrlj mice.

Atopic dermatitis (AD) is a chronic inflammatory skin disease with significant health/economic burdens. Existing therapies are not fully effective, necessitating development of new approaches for AD management. Here, we report that dietary grape powder (GP) mitigates AD-like symptoms in 2,4-dinitrofluorobenzene (DNFB)-induced AD in NC/NgaTndCrlj mice. Using prevention and intervention protocols, we tested the efficacy of 3% and 5% GP-fortified diet in a 13-weeks study. We found that GP feeding markedly inhibited development and progression of AD-like skin lesions, and caused reduction in i) epidermal thickness, mast cell infiltration, ulceration, excoriation and acanthosis in dorsal skin, ii) spleen weight, extramedullary hematopoiesis and lymph nodes sizes, and iii) ear weight and IgE levels. We also found significant modulations in 15 AD-associated serum cytokines/chemokines. Next, using quantitative global proteomics, we identified 714 proteins. Of these, 68 (normal control) and 21 (5% GP-prevention) were significantly modulated (≥2-fold) vs AD control (DNFB-treated) group, with many GP-modulated proteins reverting to normal levels. Ingenuity pathway analysis of GP-modulated proteins followed by validation using ProteinSimple identified changes in acute phase response signaling (FGA, FGB, FGG, HP, HPX, LRG1). Overall, GP supplementation inhibited DNFB-induced AD in NC/NgaTndCrlj mice in both prevention and intervention trials, and should be explored further.

Dietary Phytochemicals in Zinc Homeostasis: A Strategy for Prostate Cancer Management.

Studies have suggested an important role of the trace element zinc (Zn) in prostate biology and functions. Zn has been shown to exist in very high concentrations in the healthy prostate and is important for several prostatic functions. In prostate cancer (PCa), Zn levels are significantly decreased and inversely correlated with disease progression. Ideally, restoration of adequate Zn levels in premalignant/malignant prostate cells could abort prostate malignancy. However, studies have shown that Zn supplementation is not an efficient way to significantly increase Zn concentrations in PCa. Based on a limited number of investigations, the reason for the lower levels of Zn in PCa is believed to be the dysregulation of Zn transporters (especially ZIP and ZnT family of proteins), metallothioneins (for storing and releasing Zn), and their regulators (e.g., Zn finger transcription factor RREB1). Interestingly, the level of Zn in cells has been shown to be modulated by naturally occurring dietary phytochemicals. In this review, we discussed the effect of selected phytochemicals (quercetin, resveratrol, epigallocatechin-3-gallate and curcumin) on Zn functioning and proposes that Zn in combination with specific dietary phytochemicals may lead to enhanced Zn bioaccumulation in the prostate, and therefore, may inhibit PCa.

Genetic Manipulation of Sirtuin 3 Causes Alterations of Key Metabolic Regulators in Melanoma.

The mitochondrial sirtuin SIRT3 plays key roles in cellular metabolism and energy production, which makes it an obvious target for the management of cancer, including melanoma. Previously, we have demonstrated that SIRT3 was constitutively upregulated in human melanoma and its inhibition resulted in anti-proliferative effects in vitro in human melanoma cells and in vivo in human melanoma xenografts. In this study, we expanded our data employing knockdown and overexpression strategies in cell culture and mouse xenografts to further validate and establish the pro-proliferative function of SIRT3 in melanocytic cells, and its associated potential mechanisms, especially focusing on the metabolic regulation. We found that short-hairpin RNA (shRNA) mediated SIRT3 knockdown in G361 melanoma cells showed diminished tumorigenesis in immunodeficient Nu/Nu mice. Conversely, SIRT3 overexpressing Hs294T melanoma cells showed increased tumor growth. These effects were consistent with changes in markers of proliferation (PCNA), survival (Survivin) and angiogenesis (VEGF) in xenografted tissues. Further, in in vitro culture system, we determined the effect of SIRT3 knockdown on glucose metabolism in SK-MEL-2 cells, using a PCR array. SIRT3 knockdown caused alterations in a total of 37 genes involved in the regulation and enzymatic pathways of glucose (32 genes) and glycogen (5 genes) metabolism. Functions annotation of these identified genes, using the ingenuity pathway analysis (IPA), predicted cumulative actions of decreased cell viability/proliferation, tumor growth and reactive oxygen species (ROS), and increased apoptosis in response to SIRT3 knockdown. Further, IPA gene network analysis of SIRT3 modulated genes revealed the interactions among these genes in addition to several melanoma-associated genes. Sirtuin pathway was identified as one of the top canonical pathways showing the interaction of SIRT3 with metabolic regulatory genes along with other sirtuins. IPA analysis also predicted the inhibition of HIF1α, PKM, KDM8, PPARGC1A, mTOR, and activation of P53 and CLPP; the genes involved in major cancer/melanoma-associated signaling events. Collectively, these results suggest that SIRT3 inhibition affects cellular metabolism, to impart an anti-proliferative response against melanoma.

Recent Advancements on Immunomodulatory Mechanisms of Resveratrol in Tumor Microenvironment.

Immunomodulation of the tumor microenvironment is emerging as an important area of research for the treatment of cancer patients. Several synthetic and natural agents are being investigated for their ability to enhance the immunogenic responses of immune cells present in the tumor microenvironment to impede tumor cell growth and dissemination. Among them, resveratrol, a stilbenoid found in red grapes and many other natural sources, has been studied extensively. Importantly, resveratrol has been shown to possess activity against various human diseases, including cancer. Mechanistically, resveratrol has been shown to regulate an array of signaling pathways and processes involving oxidative stress, inflammation, apoptosis, and several anticancer effects. Furthermore, recent research suggests that resveratrol can regulate various cellular signaling events including immune cell regulation, cytokines/chemokines secretion, and the expression of several other immune-related genes. In this review, we have summarized recent findings on resveratrol's effects on immune regulatory cells and associated signaling in various cancer types. Numerous immunomodulatory effects of resveratrol suggest it may be useful in combination with other cancer therapies including immunotherapy for effective cancer management.

Cultured cardiac fibroblasts and myofibroblasts express Sushi Containing Domain 2 and assemble a unique fibronectin rich matrix.

Cardiac fibroblasts and myofibroblasts assemble and maintain extracellular matrix during normal development and following injury. Culture expansion of these cells yield a bioengineered matrix that could lead to intriguing therapeutic opportunities. For example, we reported that cultured rat cardiac fibroblasts form a matrix that can be used to delivery therapeutic stem cells. Furthermore, we reported that matrix derived from cultured human cardiac fibroblasts/myofibroblasts converted monocytes into macrophages that express interesting anti-inflammatory and pro-angiogenic properties. Expanding these matrix investigations require characterization of the source cells for quality control. In these efforts, we observed and herein report that Sushi Containing Domain 2 (SUSD2) is a novel and consistent marker for cultured human cardiac fibroblast and myofibroblasts.

Role of Polo-Like Kinase 4 (PLK4) in Epithelial Cancers and Recent Progress in its Small Molecule Targeting for Cancer Management.

The polo-like kinases (PLKs) are a family of serine/threonine kinases traditionally linked to cell-cycle regulation. A structurally unique member of this family, PLK4, has been shown to regulate centriole duplication during the cell cycle via interactions with a variety of centrosomal proteins. Recent findings suggest that PLK4 is overexpressed in various human cancers and associated with poor cancer prognosis. Although several studies have shown that PLK4 inhibition may lead to cancer cell death, the underlying mechanisms are largely unknown. In this review, we discuss the structure, localization, and function of PLK4, along with the functional significance of PLK4 in epithelial cancers and some preliminary work suggesting a role for PLK4 in the key cancer progression process epithelial-mesenchymal transition. We also discuss the potential of PLK4 as a druggable target for anticancer drug development based on critical analysis of the available data of PLK4 inhibitors in preclinical development and clinical trials. Overall, the emerging data suggest that PLK4 plays an essential role in epithelial cancers and should be further explored as a potential biomarker and/or therapeutic target. Continued detailed exploration of available and next-generation PLK4 inhibitors may provide a new dimension for novel cancer therapeutics following successful clinical trials.

PLK1 and NOTCH Positively Correlate in Melanoma and Their Combined Inhibition Results in Synergistic Modulations of Key Melanoma Pathways.

Melanoma is one of the most serious forms of skin cancer, and its increasing incidence coupled with nonlasting therapeutic options for metastatic disease highlights the need for additional novel approaches for its management. In this study, we determined the potential interactions between polo-like kinase 1 (PLK1, a serine/threonine kinase involved in mitotic regulation) and NOTCH1 (a type I transmembrane protein deciding cell fate during development) in melanoma. Employing an in-house human melanoma tissue microarray (TMA) containing multiple cases of melanomas and benign nevi, coupled with high-throughput, multispectral quantitative fluorescence imaging analysis, we found a positive correlation between PLK1 and NOTCH1 in melanoma. Furthermore, The Cancer Genome Atlas database analysis of patients with melanoma showed an association of higher mRNA levels of PLK1 and NOTCH1 with poor overall, as well as disease-free, survival. Next, utilizing small-molecule inhibitors of PLK1 and NOTCH (BI 6727 and MK-0752, respectively), we found a synergistic antiproliferative response of combined treatment in multiple human melanoma cells. To determine the molecular targets of the overall and synergistic responses of combined PLK1 and NOTCH inhibition, we conducted RNA-sequencing analysis employing a unique regression model with interaction terms. We identified the modulations of several key genes relevant to melanoma progression/metastasis, including MAPK, PI3K, and RAS, as well as some new genes such as Apobec3G, BTK, and FCER1G, which have not been well studied in melanoma. In conclusion, our study demonstrated a synergistic antiproliferative response of concomitant targeting of PLK1 and NOTCH in melanoma, unraveling a potential novel therapeutic approach for detailed preclinical/clinical evaluation.