Role of Roflumilast Combined with ESHAP Chemotherapy in Relapsed/Refractory Patients with Diffuse Large B-Cell Lymphoma

The multifaceted role of phosphodiesterase 4 in tumor: from tumorigenesis to immunotherapy

Phosphodiesterase 4 (PDE4) is an enzyme that specifically hydrolyzes the second messenger cAMP and has a critical role in the regulation of a variety of cellular functions. In recent years, PDE4 has attracted great interest in cancer research, and its role in tumorigenesis and development has been gradually elucidated. Research indicates that abnormal expression or heightened activity of PDE4 is associated with the initiation and progression of multiple cancers, including lung, colorectal, and hematological cancers, by facilitating cell proliferation, migration, invasion, and anti-apoptosis. Moreover, PDE4 also influences the tumor immune microenvironment, significantly immune evasion by suppressing anti-tumor immune responses, reducing T-cell activation, and promoting the polarization of tumor-associated macrophages toward a pro-tumorigenic phenotype. However, the PDE4 family may have both oncogenic and tumor-suppressive effects, which could depend on the specific type and grade of the tumor. PDE4 inhibitors have garnered substantial interest as potential anti-cancer therapeutics, directly inhibiting tumor cell growth and restoring immune surveillance capabilities to enhance the clearance of tumor cells. Several PDE4 inhibitors are currently under investigation with the aim of exploring their potential in cancer therapy, particularly in combination strategies with immune checkpoint inhibitors, to improve therapeutic efficacy and mitigate the side effects of conventional chemotherapy. This review provides an overview of PDE4 in tumorigenesis, drug resistance, immunotherapy, and the anti-tumor actions of its inhibitors, intending to guide the exploration of PDE4 as a new target in tumor therapy.

Roflumilast attenuates doxorubicin and cyclophosphamide combination-induced chemobrain in rats through modulation of NLRP3/ASC/caspase-1/GSDMD axis

AIM

The aim of this study is to investigate the neuroprotective effect of roflumilast, a phosphodiesterase-4 (PDE-4) inhibitor on cognitive impairment induced by doxorubicin (DOX)/cyclophosphamide (CP) combination therapy and to elucidate its modulatory effect on the pyroptosis pathway.

MATERIALS AND METHODS

Rats were allocated into five groups: a control group, a DOX/CP-intoxicated group, two groups receiving DOX/CP plus low-dose (0.5 mg/kg/day) or high-dose (1 mg/kg/day) roflumilast, and a roflumilast-only group. Behavioral assessments and brain tissue analyses were conducted, including histopathological staining and the measurement of inflammatory and oxidative stress markers.

FINDINGS

DOX/CP treatment resulted in cognitive impairment, abnormal brain histology. It significantly elevated the levels of tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and malondialdehyde (MDA). Concurrently, superoxide dismutase (SOD) activity was reduced. Pyroptosis-associated markers, including nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3), apoptosis-associated speck-like protein (ASC), caspase-1, gasdermin-D (GSDMD), and interleukin-18 (IL-18) were upregulated. Apoptotic marker caspase-3 also exhibited increased expression. Conversely, administration of roflumilast (1 mg/kg/day) for four weeks ameliorated these pathological changes. Roflumilast improved cognitive function, reduced oxidative stress, and modulated inflammatory signaling. Additionally, it suppressed pyroptotic and apoptotic pathways within hippocampal tissue.

SIGNIFICANCE

These results suggest that roflumilast exerts neuroprotective effects against chemotherapy-induced cognitive dysfunction and neurodegeneration through inhibition of the NLRP3/ASC/caspase-1/GSDMD pyroptosis pathway.

Topical and Oral Roflumilast in Dermatology: A Narrative Review

Oral roflumilast is a phosphodiesterase-4 inhibitor approved for the prevention of exacerbations of chronic obstructive pulmonary disease and chronic bronchitis. In dermatology, topical roflumilast is authorized by the US Food and Drug Administration for the treatment of plaque psoriasis and mild to moderate seborrheic dermatitis. Several studies have described the off-label use of roflumilast in dermatology, including a randomized controlled trial showing its usefulness in the treatment of psoriasis; case reports and small series have also reported successful outcomes in hidradenitis suppurativa, recurrent oral aphthosis, nummular eczema, lichen planus, and Behçet disease. Roflumilast has a favorable safety profile, similar to that of apremilast, and it is considerably cheaper than new generation drugs and even some conventional immunosuppressants. We review the pharmacokinetics and pharmacodynamics of topical and oral roflumilast and discuss potential adverse effects and both approved and off-label uses in dermatology. Roflumilast is a promising agent to consider.

[Translated aticle] Topical and Oral Roflumilast in Dermatology: A Narrative Review

Oral roflumilast is a phosphodiesterase-4 inhibitor approved for the prevention of exacerbations of chronic obstructive pulmonary disease and chronic bronchitis. In dermatology, topical roflumilast is authorized by the US Food and Drug Administration for the treatment of plaque psoriasis and mild to moderate seborrheic dermatitis. Several studies have described the off-label use of roflumilast in dermatology, including a randomized controlled trial showing its usefulness in the treatment of psoriasis; case reports and small series have also reported successful outcomes in hidradenitis suppurativa, recurrent oral aphthosis, nummular eczema, lichen planus, and Behçet disease. Roflumilast has a favorable safety profile, similar to that of apremilast, and it is considerably cheaper than new generation drugs and even some conventional immunosuppressants. We review the pharmacokinetics and pharmacodynamics of topical and oral roflumilast and discuss potential adverse effects and both approved and off-label uses in dermatology. Roflumilast is a promising agent to consider.

cAMP-PKA/EPAC signaling and cancer: the interplay in tumor microenvironment

Cancer is a complex disease resulting from abnormal cell growth that is induced by a number of genetic and environmental factors. The tumor microenvironment (TME), which involves extracellular matrix, cancer-associated fibroblasts (CAF), tumor-infiltrating immune cells and angiogenesis, plays a critical role in tumor progression. Cyclic adenosine monophosphate (cAMP) is a second messenger that has pleiotropic effects on the TME. The downstream effectors of cAMP include cAMP-dependent protein kinase (PKA), exchange protein activated by cAMP (EPAC) and ion channels. While cAMP can activate PKA or EPAC and promote cancer cell growth, it can also inhibit cell proliferation and survival in context- and cancer type-dependent manner. Tumor-associated stromal cells, such as CAF and immune cells, can release cytokines and growth factors that either stimulate or inhibit cAMP production within the TME. Recent studies have shown that targeting cAMP signaling in the TME has therapeutic benefits in cancer. Small-molecule agents that inhibit adenylate cyclase and PKA have been shown to inhibit tumor growth. In addition, cAMP-elevating agents, such as forskolin, can not only induce cancer cell death, but also directly inhibit cell proliferation in some cancer types. In this review, we summarize current understanding of cAMP signaling in cancer biology and immunology and discuss the basis for its context-dependent dual role in oncogenesis. Understanding the precise mechanisms by which cAMP and the TME interact in cancer will be critical for the development of effective therapies. Future studies aimed at investigating the cAMP-cancer axis and its regulation in the TME may provide new insights into the underlying mechanisms of tumorigenesis and lead to the development of novel therapeutic strategies.

Advances in diagnosis, treatment and prognostic factors of gastrointestinal DLBCL

Gastrointestinal diffuse large B-cell lymphoma (GI-DLBCL) is an extremely aggressive form of B-cell non-Hodgkin lymphoma (BNHL) which has complex histological characteristics and manifests a high degree of heterogeneity in terms of clinical, morphological, immunological, and genetic features. GI-DLBCL mainly spreads by infiltrating neighboring lymph nodes, and common gastrointestinal complications (GICS) such as obstruction, perforation, or bleeding, frequently arise during the progression of the disease, posing significant challenges in both diagnosing and treating the condition. Meanwhile, the incidence of GI-DLBCL has been gradually increasing in recent years, and its strong invasiveness makes it prone to being misdiagnosed or completely missed. In clinical practice, over half of the patients diagnosed with the disease are in stage III or stage IV. What makes it worse is that certain patients may not exhibit a favorable response to chemotherapy. All these lead to intricacies in management of this disease. Unfortunately, there is currently no large prospective study or evidence-based medical evidence to provide clear guidance on treatment decisions for this specific type of lymphoma. Neither do physicians have a consensus regarding the optimal approach to address this condition. Recent studies have identified the presence of various prognostic factors that significantly impact survival in GI-DLBCL, which demonstrates the unique particularity of GI-DLBCL, and could help optimize the clinical decision.