Neurotrophin Pathway Receptors NGFR and TrkA Control Perineural Invasion, Metastasis, and Pain in Oral Cancer.

Oral squamous cell carcinoma (OSCC) patients suffer from poor survival due to metastasis or locoregional recurrence, processes that are both facilitated by perineural invasion (PNI). OSCC has higher rates of PNI than other cancer subtypes, with PNI present in 80% of tumors. Despite the impact of PNI on oral cancer prognosis and pain, little is known about the genes that drive PNI, which in turn drive pain, invasion, and metastasis.

Targeting the endothelin axis as a therapeutic strategy for oral cancer metastasis and pain.

Metastasis reduces survival in oral cancer patients and pain is their greatest complaint. We have shown previously that oral cancer metastasis and pain are controlled by the endothelin axis, which is a pathway comprised of the endothelin A and B receptors (ETR and ETR). In this study we focus on individual genes of the pathway, demonstrating that the endothelin axis genes are methylated and dysregulated in cancer tissue.

Cutaneous pigmentation modulates skin sensitivity via tyrosinase-dependent dopaminergic signalling.

We propose a new mechanism of sensory modulation through cutaneous dopaminergic signalling. We hypothesize that dopaminergic signalling contributes to differential cutaneous sensitivity in darker versus lighter pigmented humans and mouse strains. We show that thermal and mechanical cutaneous sensitivity is pigmentation dependent.

OPRM1 Methylation Contributes to Opioid Tolerance in Cancer Patients.

Unlabelled: Cancer patients in pain require high doses of opioids and quickly become opioid-tolerant. Previous studies have shown that chronic cancer pain as well as high-dose opioid use lead to mu-opioid receptor downregulation. In this study we explore downregulation of the mu-opioid receptor gene (OPRM1), as a mechanism for opioid tolerance in the setting of opioid use for cancer pain.

Ex vivo nonviral gene delivery of μ-opioid receptor to attenuate cancer-induced pain.

Virus-mediated gene delivery shows promise for the treatment of chronic pain. However, viral vectors have cytotoxicity. To avoid toxicities and limitations of virus-mediated gene delivery, we developed a novel nonviral hybrid vector: HIV-1 Tat peptide sequence modified with histidine and cysteine residues combined with a cationic lipid.

TRPV1 expression level in isolectin B₄-positive neurons contributes to mouse strain difference in cutaneous thermal nociceptive sensitivity.

Differential thermal nociception across inbred mouse strains has genetic determinants. Thermal nociception is largely attributed to the heat/capsaicin receptor transient receptor potential vanilloid 1 (TRPV1); however, the contribution of this channel to the genetics of thermal nociception has not been revealed. In this study we compared TRPV1 expression levels and electrophysiological properties in primary sensory neurons and thermal nociceptive behaviors between two (C57BL/6 and BALB/c) inbred mouse strains.

TMPRSS2, a novel membrane-anchored mediator in cancer pain.

More than half of all cancer patients have significant pain during the course of their disease. The strategic localization of TMPRSS2, a membrane-bound serine protease, on the cancer cell surface may allow it to mediate signal transduction between the cancer cell and its extracellular environment. We show that TMPRSS2 expression is not only dramatically increased in the primary cancers of patients but TMPRSS2 immunopositivity is also directly correlated with cancer pain severity in these patients.

Decitabine rescues cisplatin resistance in head and neck squamous cell carcinoma.

Cisplatin resistance in head and neck squamous cell carcinoma (HNSCC) reduces survival. In this study we hypothesized that methylation of key genes mediates cisplatin resistance. We determined whether a demethylating drug, decitabine, could augment the anti-proliferative and apoptotic effects of cisplatin on SCC-25/CP, a cisplatin-resistant tongue SCC cell line.

Demethylating drugs as novel analgesics for cancer pain.

Purpose: In this study, we evaluated the analgesic potential of demethylating drugs on oral cancer pain. Although demethylating drugs could affect expression of many genes, we focused on the mu-opioid receptor (OPRM1) gene pathway, because of its role in pain processing. We determined the antinociceptive effect of OPRM1 re-expression in a mouse oral cancer model.

Alphavbeta3 suppresses the RhoA-LIMK1 pathway in K1735 melanoma.

Mucocutaneous melanoma has a five-year survival rate of less than 10 percent. The alphavbeta3 integrin promotes invasion, which requires actin reorganization by cofilin. The authors previously showed that cofilin and alphavbeta3 promote invasion.

Novel animal models of acute and chronic cancer pain: a pivotal role for PAR2.

Targeted therapy to prevent the progression from acute to chronic pain in cancer patients remains elusive. We developed three novel cancer models in mice that together recapitulate the anatomical, temporal, and functional characteristics of acute and chronic head and neck cancer pain in humans. Using pharmacologic and genetic approaches in these novel cancer models, we identified the interaction between protease-activated receptor 2 (PAR2) and serine proteases to be of central importance.

Stem cell markers as predictors of oral cancer invasion.

We previously showed that within primary tumors there exist subpopulations of cells expressing stem cell markers. Using immunofluorescence and western blotting, we examined the expression of stem cell markers tumor-rejection antigen 1-60 (TRA1-60) and octamer-binding transcription factor 3/ 4 (OCT3/4) to determine their relationship with cell invasiveness. Six human oral cancer cell lines were examined and a direct correlation was found between expression of these stem cell markers and invasion.

Analgesia targeting IB4-positive neurons in cancer-induced mechanical hypersensitivity.

Unlabelled: Cancer patients often suffer from pain and most will be prescribed μ-opioids. μ-opioids are not satisfactory in treating cancer pain and are associated with multiple debilitating side effects. Recent studies show that μ and δ opioid receptors are separately expressed on IB4 (-) and IB4 (+) neurons, which control thermal and mechanical pain, respectively.

Re-expression of the methylated EDNRB gene in oral squamous cell carcinoma attenuates cancer-induced pain.

Endothelin-1 is a vasoactive peptide that activates both the endothelin A (ET(A)) and endothelin B (ET(B)) receptors, and is secreted in high concentrations in many different cancer environments. Although ET(A) receptor activation has an established nociceptive effect in cancer models, the role of ET(B) receptors on cancer pain is controversial. EDNRB, the gene encoding the ET(B) receptor, has been shown to be hypermethylated and transcriptionally silenced in many different cancers.

Nerve growth factor links oral cancer progression, pain, and cachexia.

Cancers often cause excruciating pain and rapid weight loss, severely reducing quality of life in cancer patients. Cancer-induced pain and cachexia are often studied and treated independently, although both symptoms are strongly linked with chronic inflammation and sustained production of proinflammatory cytokines. Because nerve growth factor (NGF) plays a cardinal role in inflammation and pain, and because it interacts with multiple proinflammatory cytokines, we hypothesized that NGF acts as a key endogenous molecule involved in the orchestration of cancer-related inflammation.

EMMPRIN expression in oral SCC is regulated by FYN kinase.

This study shows that the expression of the extracellular matrix metalloproteinase inducer (EMMPRIN) in oral squamous cell carcinoma cells (SCC) depends upon activation of the Src Family kinaseFyn; and that EMMPRIN and β6 form a complex that requires active Fyn and the full length β6 integrin cytoplasmic domain. Fyn is also important for matrix remodeling as it regulates both matrix type 1 metalloproteinase (MT1-MMP) and tissue inhibitor of metalloproteinase-1 and -2 (TIMP1/2). The tumor promoter/suppressor caveolin-1, which associates with MT1-MMP, also requires FYN activation for expression.

Modulation of EGFR by oral squamous cell carcinoma cell lines.

Oral cancer is the sixth most frequent cancer worldwide. Prognosis for these patients remains poor. Recently, the epidermal growth factor receptor has been targeted as an adjunct to radiotherapy and surgery with limited success.

Identification of {alpha}v{beta}6-positive stem cells in oral squamous cell carcinoma.

Oral squamous cell carcinoma (SCC) is composed of a heterogeneous population of cells which range anywhere from epithelial to mesenchymal in phenotype. Several oral cancer specimens with antibodies to TRA160, a marker of pluripotent cells, were screened. Compared with the well differentiated lesions, pluripotent cells were more numerous in specimens from poorly differentiated tumors.

The role of the integrin alpha v beta6 in regulating the epithelial to mesenchymal transition in oral cancer.

In this study, we evaluated whether the forced expression of beta6 integrin would modulate the epithelial to mesenchymal transition (EMT). When the full length beta6 integrin was expressed in poorly invasive squamous cell carcinoma SCC9 cells, the resulting SCC9/6 cells acquired a fibroblast-like morphology, increased expression of the mesenchymal marker vimentin and reduced expression of the epithelial markers keratin and E-cadherin. SCC9beta6D1 cells, which express a truncated form of beta6 subunit lacking the C-terminal 11 amino acids (AA), retained their epithelial morphology and did not alter vimentin or E-cadherin expression.

EMMPRIN modulates migration and deposition of TN-C in oral squamous carcinoma.

The extracellular matrix metalloproteinase inducer (EMMPRIN), found on the surface of many tumor cells, stimulates the production of matrix metalloproteinases (MMPs) by both fibroblasts and the tumor cells themselves. To evaluate its possible role as a tumor promoter, we first overexpressed EMMPRIN, by retroviral transduction, into poorly invasive squamous cell carcinoma (SCC) cells. Secondly, we knocked down its expression using small interfering RNA (siRNA) in invasive SCC cells.

Alphavbeta3 integrin and cofilin modulate K1735 melanoma cell invasion.

Cytoskeletal reorganization is partially mediated through cofilin, an actin assembly regulatory protein. Cofilin activity is modulated by reversible phosphorylation at Ser3. In this study, using K1735 murine melanoma cells, we examined the relationship between beta3-integrin expression, phosphorylation of cofilin, and metalloproteinase production.

The expression of integrin alpha(v)beta6 promotes the epithelial cell morphology and suppresses invasive behavior in transformed oral keratinocytes.

The expression of the integrin alpha(v)beta6 has been correlated with oral SCC invasion. We evaluated its expression in three 4NQO transformed murine oral keratinocyte cell lines (B7E3, B7E11 and B4B8). The B7E3 cells were negative for beta6, whereas the B7E11 and the B4B8 cells were both positive.

Tenascin-C deposition requires beta3 integrin and Src.

In this study we now show that deposition of the mesenchymal matrix marker, tenascin-C (TN-C), is mediated through beta3 expression and activation of Src. There was a striking upregulation of TN-C matrix organization in cell lines expressing beta3 and activated Src when compared to cell lines with neither of these attributes. When beta3 function was suppressed so was the deposition of TN-C.

Matrix metalloproteinases and TGFbeta1 modulate oral tumor cell matrix.

The integrin beta6 has been shown to promote invasion and experimental metastasis by oral squamous cell carcinoma (SCC). In this study, we demonstrate that the expression of beta6 by oral SCC9 cells increased activation of the UPA --> MMP3 --> MMP9 pathway. We also demonstrate that the deposition of fibronectin and tenascin-C matrices by SCC9beta6 cells and peritumor fibroblast cocultures is counter-regulated by the UPA --> MMP3 --> MMP9 pathway.