The entanglement of extracellular matrix molecules and immune checkpoint inhibitors in cancer: a systematic review of the literature

Reciprocal Modulation of Tumour and Immune Cell Motility: Uncovering Dynamic Interplays and Therapeutic Approaches

Dysregulated cell movement is a hallmark of cancer progression and metastasis, the leading cause of cancer-related mortality. The metastatic cascade involves tumour cell migration, invasion, intravasation, dissemination, and colonisation of distant organs. These processes are influenced by reciprocal interactions between cancer cells and the tumour microenvironment (TME), including immune cells, stromal components, and extracellular matrix proteins. The epithelial-mesenchymal transition (EMT) plays a crucial role in providing cancer cells with invasive and stem-like properties, promoting dissemination and resistance to apoptosis. Conversely, the mesenchymal-epithelial transition (MET) facilitates metastatic colonisation and tumour re-initiation. Immune cells within the TME contribute to either anti-tumour response or immune evasion. These cells secrete cytokines, chemokines, and growth factors that shape the immune landscape and influence responses to immunotherapy. Notably, immune checkpoint blockade (ICB) has transformed cancer treatment, yet its efficacy is often dictated by the immune composition of the tumour site. Elucidating the molecular cross-talk between immune and cancer cells, identifying predictive biomarkers for ICB response, and developing strategies to convert cold tumours into immune-active environments is critical to overcoming resistance to immunotherapy and improving patient survival.

Extracellular matrix and pregnancy: functions and opportunities caught in the net

The extracellular matrix is a complex network of macromolecules that support the growth and homeostatic development of organisms. By conveying multiple signaling cascades, it impacts on several biological processes and influences the behaviour of numerous cell types. During the endometrial cycle and the key events necessary for a correct embryo implantation and placentation, this bioactive meshwork is substantially modified to favour endometrial receptivity and vascular adaptation, trophoblast cell migration, and immune activation as well. A correct extracellular remodeling is fundamental for the establishment of a physiological pregnancy; indeed, the occurrence of altered matrix modifications associates with gestational disorders such as preeclampsia. In the present review, we will critically evaluate the role of pivotal matrix constituents in regulating the key steps of embryo implantation and placentation, provide up-to-date information concerning their primary mechanisms of action and discuss on their potential as a novel source of biomarkers and therapeutic targets.

Suppression of Spry1 reduces HIF1α-dependent glycolysis and impairs angiogenesis in BRAF-mutant cutaneous melanoma

BACKGROUND

About 50% of cutaneous melanoma (CM) harbors the activating BRAFV600 mutation which exerts most of the oncogenic effects through the MAPK signaling pathway. In the last years, a number of MAPK modulators have been identified, including Spry1. In this context, we have recently demonstrated that knockout of Spry1 (Spry1KO) in BRAFV600-mutant CM led to cell cycle arrest and apoptosis, repressed cell proliferation in vitro, and reduced tumor growth in vivo. Despite these findings, however, the precise molecular mechanism linking Spry1 to BRAFV600-mutant CM remains to be elucidated.

MATERIALS AND METHODS

Immunoprecipitation coupled to mass spectrometry was employed to gain insight into Spry1 interactome. Spry1 gene was knocked-out using the CRISPR strategy in the BRAF-mutant cell lines. Transmission electron microscopy was used to assess the relationship between Spry1 expression and mitochondrial morphology. By using in vitro and in vivo models, the effects of Spry1KO were investigated through RNA-sequencing, quantitative real-time PCR, Western blot, and immunofluorescence analyses. The Seahorse XF24 assay allowed real-time measurement of cellular metabolism in our model. Angiogenic potential was assessed through in vitro tube formation assays and in vivo CD31 staining.

RESULTS

Spry1 was mainly located in mitochondria in BRAFV600-mutant CM cells where it interacted with key molecules involved in mitochondrial homeostasis. Spry1 loss resulted in mitochondrial shape alterations and dysfunction, which associated with increased reactive oxygen species production. In agreement, we found that nuclear hypoxia-inducible factor-1 alpha (HIF1α) protein levels were reduced in Spry1KO clones both in vitro and in vivo along with the expression of its glycolysis related genes. Accordingly, Ingenuity Pathway Analysis identified "HIF1α Signaling" as the most significant molecular and cellular function affected by Spry1 silencing, whereas the glycolytic function was significantly impaired in Spry1 depleted BRAFV600-mutant CM cells. In addition, our results indicated that the expression of the vascular endothelial growth factor A was down-regulated following Spry1KO, possibly as a result of mitochondrial dysfunction. Consistently, we observed a substantial impairment of angiogenesis, as assessed by the tube formation assay in vitro and the immunofluorescence staining of CD31 in vivo.

CONCLUSIONS

Altogether, these findings identify Spry1 as a potential regulator of mitochondrial homeostasis, and uncover a previously unrecognized role for Spry1 in regulating nuclear HIF1α expression and angiogenesis in BRAFV600-mutant CM.

SIGNIFICANCE

Spry1KO profoundly impacts on mitochondria homeostasis, while concomitantly impairing HIF1α-dependent glycolysis and reducing angiogenesis in BRAF-mutant CM cells, thus providing a potential therapeutic target to improve BRAFV600-mutant CM treatment.

Proteoglycans of basement membranes: Crucial controllers of angiogenesis, neurogenesis, and autophagy

Anti-angiogenic therapy is an established method for the treatment of several cancers and vascular-related diseases. Most of the agents employed target the vascular endothelial growth factor A, the major cytokine stimulating angiogenesis. However, the efficacy of these treatments is limited by the onset of drug resistance. Therefore, it is of fundamental importance to better understand the mechanisms that regulate angiogenesis and the microenvironmental cues that play significant role and influence patient treatment and outcome. In this context, here we review the importance of the three basement membrane heparan sulfate proteoglycans (HSPGs), namely perlecan, agrin and collagen XVIII. These HSPGs are abundantly expressed in the vasculature and, due to their complex molecular architecture, they interact with multiple endothelial cell receptors, deeply affecting their function. Under normal conditions, these proteoglycans exert pro-angiogenic functions. However, in pathological conditions such as cancer and inflammation, extracellular matrix remodeling leads to the degradation of these large precursor molecules and the liberation of bioactive processed fragments displaying potent angiostatic activity. These unexpected functions have been demonstrated for the C-terminal fragments of perlecan and collagen XVIII, endorepellin and endostatin. These bioactive fragments can also induce autophagy in vascular endothelial cells which contributes to angiostasis. Overall, basement membrane proteoglycans deeply affect angiogenesis counterbalancing pro-angiogenic signals during tumor progression, and represent possible means to develop new prognostic biomarkers and novel therapeutic approaches for the treatment of solid tumors.

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.