Faculty Bibliography

Oral cancer is often painful and lethal. Oral cancer progression and pain may result from shared pathways that involve unresolved inflammation and elevated levels of pro-inflammatory cytokines. Resolvin D-series (RvDs) are endogenous lipid mediators derived from omega-3 fatty acids that exhibit pro-resolution and anti-inflammatory actions. These mediators have recently emerged as a novel class of therapeutics for diseases that involve inflammation; the specific roles of RvDs in oral cancer and associated pain are not defined. The present study investigated the potential of RvDs (RvD1 and RvD2) to treat oral cancer and alleviate oral cancer pain. We found down-regulated mRNA levels of GPR18 and GPR32 (which code for receptors RvD1 and RvD2) in oral cancer cells. Both RvD1 and RvD2 inhibited oral cancer proliferation in vitro. Using two validated mouse oral squamous cell carcinoma xenograft models, we found that RvD2, the more potent anti-inflammatory lipid mediator, significantly reduced tumor size. The mechanism of this action might involve suppression of IL-6, C-X-C motif chemokine 10 (CXCL10), and reduction of tumor necrosis. RvD2 generated short-lasting analgesia in xenograft cancer models, which coincided with decreased neutrophil infiltration and myeloperoxidase activity. Using a cancer supernatant model, we demonstrated that RvD2 reduced cancer-derived cytokines/chemokines (TNF-α, IL-6, CXCL10, and MCP-1), cancer mediator-induced CD11b⁺Ly6G^- myeloid cells, and nociception. We infer from our results that manipulation of the endogenous pro-resolution pathway might provide a novel approach to improve oral cancer and cancer pain treatment.

Oral cancer patients report severe pain during function. Inflammation plays a role in the oral cancer microenvironment; however, the role of immune cells and associated secretion of inflammatory mediators in oral cancer pain has not been well defined. In this study, we utilized two oral cancer mouse models: a cell line supernatant injection model and the 4-nitroquinoline-1-oxide (4NQO) chemical carcinogenesis model. We used the two models to study changes in immune cell infiltrate and orofacial nociception associated with oral squamous cell carcinoma (oSCC). Oral cancer cell line supernatant inoculation and 4NQO-induced oSCC resulted in functional allodynia and neuronal sensitization of trigeminal tongue afferent neurons. While the infiltration of immune cells is a prominent component of both oral cancer models, our use of immune-deficient mice demonstrated that oral cancer-induced nociception was not dependent on the inflammatory component. Furthermore, the inflammatory cytokine, tumor necrosis factor alpha (TNFa), was identified in high concentration in oral cancer cell line supernatant and in the tongue tissue of 4NQO-treated mice with oSCC. Inhibition of TNFa signaling abolished oral cancer cell line supernatant-evoked functional allodynia and disrupted T cell infiltration. With these data, we identified TNFa as a prominent mediator in oral cancer-induced nociception and inflammation highlighting the need for further investigation in neural-immune communication in cancer pain.

Widespread pain and anxiety are commonly reported in cancer patients. We hypothesize that cancer is accompanied by attenuation of endogenous opioid-mediated inhibition, which subsequently causes widespread pain and anxiety. To test this hypothesis we used a mouse model of oral squamous cell carcinoma (SCC) in the tongue. We found that mice with tongue SCC exhibited widespread nociceptive behaviors in addition to behaviors associated with local nociception that we reported previously. Tongue SCC mice exhibited a pattern of reduced opioid receptor expression in the spinal cord; intrathecal administration of respective mu (MOR), delta (DOR), and kappa (KOR) opioid receptor agonists reduced widespread nociception in mice, except for the fail flick assay following administration of the MOR agonist. We infer from these findings that opioid receptors contribute to widespread nociception in oral cancer mice. Despite significant nociception, mice with tongue SCC did not differ from sham mice in anxiety-like behaviors as measured by the open field assay and elevated maze. No significant differences in c-Fos staining were found in anxiety-associated brain regions in cancer relative to control mice. No correlation was found between nociceptive and anxiety-like behaviors. Moreover, opioid receptor agonists did not yield a statistically significant effect on behaviors measured in the open field and elevated maze in cancer mice. Lastly, we used an acute cancer pain model (injection of cancer supernatant into the mouse tongue) to test whether adaptation to chronic pain is responsible for the absence of greater anxiety-like behavior in cancer mice. No changes in anxiety-like behavior were observed in mice with acute cancer pain.

Cancer patients in pain require high doses of opioids and quickly become opioid-tolerant. Previous studies have shown that both chronic cancer pain and high dose opioid use lead to mu-opioid receptor down-regulation. In this study we explore down-regulation of OPRM1, the mu-opioid receptor gene, as a mechanism f,or opioid tolerance in the setting of opioid use for cancer pain. We demonstrate in a cohort of 84 cancer patients that high dose opioid use correlates with OPRM1 hypermethylation in peripheral leukocytes of these patients. We then reverse-translate our clinical findings by creating a mouse cancer pain model; we create opioid tolerance in the mouse cancer model to mimic opioid tolerance in the cancer patients. Using this model we determine the functional significance of OPRM1 methylation on cancer pain and opioid tolerance. We focus on two main cells within the cancer microenvironment: the cancer cell and the neuron. We show that targeted re-expression of mu-opioid receptor on cancer cells inhibits mechanical and thermal hypersensitivity, and prevents opioid tolerance, in the mouse model. The resultant analgesia and protection against opioid tolerance are likely due to preservation of mu-opioid receptor expression on the cancer-associated neurons.

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. Meta-analyses in humans and mice, along with our own mouse behavioural studies, reveal higher thermal sensitivity in pigmented skin relative to less-pigmented or albino skin. We show that dopamine from melanocytes activates the D1-like dopamine receptor on primary sensory neurons. Dopaminergic activation increases expression of the heat-sensitive TRPV1 ion channel and reduces expression of the mechanically-sensitive Piezo2 channel; thermal threshold is lower and mechanical threshold is higher in pigmented skin.

Background: In this study, we developed integrative, personalized prognostic models for breast cancer recurrence and overall survival (OS) that consider receptor subtypes, epidemiological data, quality of life (QoL), and treatment. Methods: 15,314 women with stage I to III invasive primary breast cancer treated at The University of Texas MD Anderson Cancer Center between 1997 and 2012 was used to generate prognostic models by Cox regression analysis including 10,809 women as discovery population (median follow-up: 6.09 years, 1,144 recurrence and 1,627 deaths) and 4,505 women as validation population (median follow-up: 7.95 years, 684 recurrence and 1,095 deaths). Model performance was assessed by calculating the area under the curve (AUC) and calibration analysis and compared with Nottingham Prognostic Index (NPI) and PREDICT. Results: In addition to the known clinical/pathological variables, the model for recurrence included alcohol consumption while the model for OS included smoking status and physical component summary score. The AUCs for recurrence and OS were 0.813 and 0.810 in the discovery and 0.807 and 0.803 in the validation, respectively, compared to AUC of 0.761 and 0.753 in discovery and 0.777 and 0.751 in validation for NPI. Our model further showed better calibration compared to PREDICT. We also developed race-specific and receptor subtype-specific models with comparable AUC. Racial disparity was evident in the distributions of many risk factors and clinical presentation of the disease. Conclusions: Our integrative prognostic models for breast cancer exhibit high discriminatory accuracy and excellent calibration and are the first to incorporate receptor subtype, epidemiological and QoL data

BACKGROUND: In order to generate valid results in RCTs, it is important to collect unbiased data. Behavioral intervention trials are more difficult to blind than pharmacologic trials. In our ongoing behavioral trial, PATRIOT, which aims to prevent foot complications in diabetes through improved self-care, we are intervening both face-to-face as well as remotely. Consequently blinding is more difficult. Here we illustrate the different blinding processes used. METHODS: In the PATRIOT trial, following randomization during the baseline visit, the intervention group receives computer-based education and demonstration on how to use a special foot thermometer. Following that, intervention participants receive a comprehensive intervention that includes regular telephone counseling and tailored mailings. The control group receives health prevention strategies not related to foot care. For this complex intervention, we needed to develop new strategies to maintain blinding at the participant, research assistant (RA), counselor, outcome adjudicator and data analyst levels. We created a "Blinding Tracker" to identify unblinded and blinded staff so that participants pass from unblinded to blinded staff so that only blinded staff collect data. The integrity of the study is maintained by careful monitoring of blinding with any break in blinding being contained. RESULTS: To date, we have enrolled 221 participants. While participants know the arm to which they are randomized, we needed to make sure that the staff collecting data are blinded. Participants are educated throughout the whole study process by the telephone counselors about the importance of blinding using non-scientific descriptions. Though the counselors know their participant's treatment assignment, they do not know their foot photography results and other outcomes. The RA's, who conduct study visits and collect data, are blinded to treatment assignment. To improve efficiency and preserve blinding, we have different RAs for different phases of a participant's progress. Initially, RAs are initially blinded, but by the end of their involvement with a particular subject, when data collection is done, they become unblinded so they can show the educational videos and demonstrate foot thermometer use. However, RA's can also become unblinded prematurely. To date, out of 96 six-month visits, there have been 26 such instances. RAs are subsequently transitioned off a particular subject to be replaced by a blinded RA. We will also control for RA blinding in the analysis. The adjudicators who read the foot photographs to determine outcomes and the statisticians are blinded to treatment assignment. CONCLUSIONS: Novel techniques have been used to achieve and maintain blinding, but it is resource intensive. While conducting complex trials, vigilance and responsiveness are needed. Finally, blinding information should be incorporated in the analysis in order to get the most valid results

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. The vector has high transfection efficiency with little cytotoxicity in cancer cell lines including HSC-3 (human tongue squamous cell carcinoma) and exhibits differential expression in HSC-3 ( approximately 45-fold) relative to HGF-1 (human gingival fibroblasts) cells. We used the nonviral vector to transfect cancer with OPRM1, the mu-opioid receptor gene, as a novel method for treating cancer-induced pain. After HSC-3 cells were transfected with OPRM1, a cancer mouse model was created by inoculating the transfected HSC-3 cells into the hind paw or tongue of athymic mice to determine the analgesic potential of OPRM1 transfection. Mice with HSC-3 tumors expressing OPRM1 demonstrated significant antinociception compared with control mice. The effect was reversible with local naloxone administration. We quantified beta-endorphin secretion from HSC-3 cells and showed that HSC-3 cells transfected with OPRM1 secreted significantly more beta-endorphin than control HSC-3 cells. These findings indicate that nonviral delivery of the OPRM1 gene targeted to the cancer microenvironment has an analgesic effect in a preclinical cancer model, and nonviral gene delivery is a potential treatment for cancer pain.