Therapeutic effect of topical 5-fluorouracil in conjunctival squamous carcinoma is associated with changes in matrix metalloproteinases and tissue inhibitor of metalloproteinases expression

Building a pathway to recovery: Targeting ECM remodeling in CNS injuries

Extracellular matrix (ECM) is a complex and dynamic network of proteoglycans, proteins, and other macromolecules that surrounds cells in tissues. The ECM provides structural support to cells and plays a critical role in regulating various cellular functions. ECM remodeling is a dynamic process involving the breakdown and reconstruction of the ECM. This process occurs naturally during tissue growth, wound healing, and tissue repair. However, in the context of central nervous system (CNS) injuries, dysregulated ECM remodeling can lead to the formation of fibrotic and glial scars. CNS injuries encompass various traumatic events, including concussions and fractures. Following CNS trauma, the formation of glial and fibrotic scars becomes prominent. Glial scars primarily consist of reactive astrocytes, while fibrotic scars are characterized by an abundance of ECM proteins. ECM remodeling plays a pivotal and tightly regulated role in the development of these scars after spinal cord and brain injuries. Various factors like ECM components, ECM remodeling enzymes, cell surface receptors of ECM molecules, and downstream pathways of ECM molecules are responsible for the remodeling of the ECM. The aim of this review article is to explore the changes in ECM during normal physiological conditions and following CNS injuries. Additionally, we discuss various approaches that target various factors responsible for ECM remodeling, with a focus on promoting axon regeneration and functional recovery after CNS injuries. By targeting ECM remodeling, it may be possible to enhance axonal regeneration and facilitate functional recovery after CNS injuries.

The impact of anticancer drugs on the ocular surface

Cancer is a global health problem and is one of the leading causes of death worldwide. Pleasingly, the rate of survival has improved and continues in an upward trend mainly due to better diagnosis and treatment modalities. In particular, the development of anticancer drugs including cytotoxic chemotherapy, hormonal agents and targeted therapies have provided the most effective treatment options in combatting cancerous cells. However, the antineoplastic mechanisms of these drugs can also lead to undesirable systemic and ocular side effects resulting from cytotoxicity, inflammation and neurotoxicity. While survival rates are projected to increase with time, the number of patients presenting with these side effects that can substantially impact quality of life will also rise. The current paper reviews the ocular surface and adnexal side effects of anticancer drugs, the appropriate management and possible interactions between drugs for ocular surface pathology treatment and the anticancer drugs.

[Management of squamous cell carcinoma of the conjunctiva in a young patient: Case report]

Squamous cell carcinoma is the most common malignant tumor of the bulbar conjunctiva. However, it often remains under-diagnosed and exposed to therapeutic delay. The aim of this work is to elucidate the diagnostic and therapeutic difficulties posed by this tumor and to appreciate its prognosis.

Knockdown delta-5-desaturase in breast cancer cells that overexpress COX-2 results in inhibition of growth, migration and invasion via a dihomo-γ-linolenic acid peroxidation dependent mechanism

BACKGROUND

Cyclooxygenase-2 (COX-2), the inducible COX form, is a bi-functional membrane-bound enzyme that typically metabolizes arachidonic acid (downstream ω-6 fatty acid) to form 2-series of prostaglandins known to be involved in cancer development. Overexpression of COX-2 has been found in a majority of breast carcinomas, and has also been associated with increased severity and the development of the metastasis. Our lab recently demonstrated that COX-2 can also metabolize dihomo-γ-linolenic acid (DGLA, a precursor of ω-6 arachidonic acid) to produce an anti-cancer byproduct, 8-hydroxyoctanoic acid (8-HOA) that can inhibit growth and migration of colon and pancreatic cancer cells. We thus tested whether our strategy of knocking down delta-5-desaturase (D5D, the key enzyme that converts DGLA to arachidonic acid) in breast cancer cells overexpressing COX-2 can also be used to promote 8-HOA formation, thereby suppressing cancer growth, migration, and invasion.

METHODS

SiRNA and shRNA transfection were used to knock down D5D expression in MDA-MB 231 and 4 T1 cells (human and mouse breast cancer cell lines expressing high COX-2, respectively). Colony formation assay, FITC Annexin V/PI double staining, wound healing and transwell assay were used to assess the effect of our strategy on inhibition of cancer growth, migration, and invasion. GC/MS was used to measure endogenous 8-HOA, and western blotting was performed to evaluate the altered key protein expressions upon the treatments.

RESULTS

We demonstrated that D5D knockdown licenses DGLA to inhibit growth of breast cancer cells via promoting formation of 8-HOA that can inhibit histone deacetylase and activate cell apoptotic proteins, such as procaspase 9 and PARP. Our strategy can also significantly inhibit cancer migration and invasion, associated with altered expression of MMP-2/- 9, E-cadherin, vimentin and snail. In addition, D5D knockdown and DGLA supplementation greatly enhanced the efficacy of 5-fluorouracil on breast cancer growth and migration.

CONCLUSIONS

Consistent to our previous studies on colon and pancreatic cancer, here we demonstrate again that the high level of COX-2 in breast cancer cells can be capitalized on inhibiting cancer growth and migration. The outcome of this translational research could guide us to develop new anti-cancer strategy and/or to improve current chemotherapy for breast cancer treatment.

Inhibition of cancer migration and invasion by knocking down delta-5-desaturase in COX-2 overexpressed cancer cells

We recently reported that knockdown of delta-5-desaturase (a key enzyme that converts dihomo-γ-linolenic acid, DGLA, to the downstream ω-6 arachidonic acid) promotes formation of an anti-cancer byproduct 8-hydroxyoctanoic acid from cyclooxygenase (COX)-catalyzed DGLA peroxidation. 8-hydroxyoctanoic acid can exert its growth inhibitory effect on cancer cells (e.g. colon and pancreatic cancer) by serving as a histone deacetylase inhibitor. Since histone deacetylase inhibitors have been well-known to suppress cancer cell migration and invasion, we thus tested whether knockdown of delta-5-desaturase and DGLA treatment could also be used to inhibit cancer migration and invasion of colon cancer and pancreatic cancer cells. Wound healing assay, transwell assay and western blot were used to assess cell migration and invasion as well as the associated molecular mechanisms. Formation of threshold level of 8-hydroxyoctanoic acid was quantified from COX-catalyzed DGLA peroxidation in the cancer cells that overexpress COX-2 and their delta-5-desaturases were knocked down by shRNA transfection. Our results showed that knockdown of delta-5-desaturase along with DGLA supplement not only significantly inhibited cell migration, but also improved the efficacies of 5-flurouracil and gemcitabine, two frontline chemotherapy drugs currently used in the treatment of colon and pancreatic cancer, respectively. The molecular mechanism behind these observations is that 8-hydroxyoctanoic acid inhibits histone deacetylase, resulting in downregulation of cancer metastasis promotors, e.g., MMP-2 and MMP-9 as well as upregulation of cancer metastasis suppressor, e.g. E-cadherin. For the first time, we demonstrated that we could take the advantage of the common phenomenon of COX-2 overexpression in cancers to inhibit cancer cell migration and invasion. With the shifting paradigm of COX-2 cancer biology, our research outcome may provide us a novel cancer treatment strategy.

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High level of COX-2 could be used to inhibit cancer cell migration and invasion.

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8-hydroxyoctanoic acid suppresses cancer migration and invasion via inhibiting HDAC.

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D5D knockdown and DGLA improves efficacy of chemotherapy to inhibit cancer metastasis.

[Conjunctival epidermoid carcinoma revealed by a chronic limbic corneal ulceration]

PURPOSE

Conjunctival epidermoid carcinoma (CEC) is a rare tumor affecting mainly the perilimbal region of the bulbar conjunctiva. We report an atypical presentation of a CEC mimicking a Mooren pseudo-ulcer.

CASE REPORT

A 78-year-old man presented a limbic corneal ulcer of the left eye that had appeared a few months before. Ophthalmologic examination showed a thinning limbic corneal ulceration, associated with substantial conjunctival thickening. The diagnosis of Mooren pseudo-ulcer was first suspected. Etiological investigations were negative. The worsening of the corneal ulcer led us to perform surgical excision on the conjunctiva around the ulcer. Histologic examination concluded in an invasive conjunctival carcinoma. Adjuvant radiotherapy was required because of incomplete surgical excision and chorion tumoral invasion.

5-Fluorouracil for the treatment of intraepithelial neoplasia and squamous cell carcinoma of the conjunctiva, and cornea

Objective:

To evaluate the efficacy and risks of complications of pulse dosing of topical 5-fluorouracil (5-FU) in the treatment of corneal intraepithelial neoplasia (CIN), and conjunctival squamous cell carcinoma (SCC).

Design:

Prospective, noncomparative case series.

Participants:

Fifteen patients with histological evidence CIN or SCC of the conjunctiva and cornea were identified by tumor biopsy.

Methods:

All patients clinically evident of CIN, or SCC were evaluated, with maximum 30 months of follow-up were treated with pulsed dosing of 1% 5-FU. Treatment cycles were defined as four times per day for 4 days using the medication followed by 30 days without medication. The number of initial treatment was six cycles.

Results:

The mean age of the 15 patients was 50.8 years (range 25–78 years). Excision biopsy proved seven cases as CIN, and eight cases as locally invasive SCC. All patients remained disease free with a mean follow-up of 14.53 months (range 6–30 months). Additional chemotherapy was given after the initial treatment cycles, only for one case. 5-FU caused mild temporary local irritation, but no long-term intraocular or extra ocular complications.

Conclusions:

Adjuvant 1% topical 5-FU appears to be effective in the prevention of recurrence of conjunctival or corneal CIN and SCC after excision biopsy. Our results indicate that at least six cycles of topical 1% 5-FU is required to prevent local recurrence in the long term. It is well-tolerated and an effective method of treatment. No complications that would preclude use of our dose regimen were noted.