: Non-surgical treatments for cervical intraepithelial neoplasia 2/3 (CIN2/3) are needed as surgical treatments have been shown to double preterm delivery rate. The goal of this study was to demonstrate safety of a human papillomavirus (HPV) therapeutic vaccine called PepCan, which consists of four current good-manufacturing production-grade peptides covering the HPV type 16 E6 protein and skin test reagent as a novel adjuvant.: The study was a single-arm, single-institution, dose-escalation phase I clinical trial, and the patients (n = 24) were women with biopsy-proven CIN2/3. Four injections were administered intradermally every 3 weeks in limbs. Loop electrical excision procedure (LEEP) was performed 12 weeks after the last injection for treatment and histological analysis. Six subjects each were enrolled (50, 100, 250, and 500 μg per peptide). : The most common adverse events (AEs) were injection site reactions, and none of the patients experienced dose-limiting toxicities. The best histological response was seen at the 50 μg dose level with a regression rate of 83% (n = 6), and the overall rate was 52% (n = 23). Vaccine-induced immune responses to E6 were detected in 65% of recipients (significantly in 43%). Systemic T-helper type 1 (Th1) cells were significantly increased after four vaccinations ( = 0.02). : This study demonstrated that PepCan is safe. A significantly increased systemic level of Th1 cells suggests that which induces interleukin-12 (IL-12) , may have a Th1 promoting effect. A phase II clinical trial to assess the full effect of this vaccine is warranted.
In the dose-escalation phase of a Phase I clinical trial in which six subjects each were vaccinated with PepCan at the 50, 100, 250, and 500μg per peptide dose, the 50μg dose showed the best histological regression rate. Ten additional subjects were vaccinated at this dose in the final dose phase. As with the dose-escalation phase, no dose-limiting toxicities were observed. Overall, the histological regression rates were 50% at the 50μg dose (7 of 14) and 100μg dose (3 of 6), and 45% overall (14 of 31). Of subjects in whom HPV type 16 (HPV 16) was detected at entry, it became undetectable in 3 subjects after vaccination, and the viral loads significantly decreased in 9 subjects in whom HPV 16 infection was detected at entry and exit (p=0.008). Immune profiling revealed increased T-helper type 1 cells after vaccinations (p=0.02 and p=0.0004 after 2 and 4 vaccinations respectively). T-helper type 2 cells initially increased after 2 vaccinations (p=0.01), but decreased below the baseline level after 4 vaccinations although not significantly. Pre-vaccination regulatory T-cell levels were significantly lower in histological responders compared to non-responders (p=0.03). Feasibility of testing plasma for multiplex cytokine/chemokine analysis and of performing proteomic analysis of PBMCs was examined for potentially identifying biomarkers in the future. While these analyses are feasible to perform, attention needs to be given to how soon the blood samples would be processed after phlebotomy. As sufficient safety of PepCan has been demonstrated, enrollment for the Phase II clinical trial has been opened.
Cervical cancer is the fourth most common cancer in women and is almost exclusively caused by human papillomavirus (HPV) infection. HPV is also frequently associated with other cancers arising from mucosal epithelium, including anal and oropharyngeal cancers, which are becoming more common in both men and women. Viral persistence and progression through precancerous lesion stages are prerequisites for HPV-associated cancer and reflect the inability of cell-mediated immune mechanisms to clear infections and eliminate abnormal cells in some individuals. Cell-mediated immune responses are initiated by innate pathogen sensing and subsequent secretion of soluble immune mediators and amplified by the recruitment and activation of effector T lymphocytes. This review discusses early defensive mechanisms of innate responders to natural HPV infection, their influence on response polarization, and the underappreciated role of keratinocytes in this process. Human papillomavirus (HPV) infects epithelial cells of the skin and mucosal tissues and is best known for its causal role in cervical cancer (1, 2), the fourth most common cancer in women worldwide (3). HPV remains a serious public health problem despite the availability of effective prophylactic vaccines such as Gardasil (Merck, Whitehouse Station, NJ, USA) and Cervarix (GlaxoSmithKline Biologicals, Rixensart, Belgium). In the United States in 2009, cervical cancer represented 53.4% of the newly diagnosed HPV-associated cancers in women and oropharyngeal cancer represented 78.2% of the newly diagnosed HPV-associated cancers in men (4). The incidence rates of HPV-associated anal and oropharyngeal cancers in both men and women increased between 2000 and 2009 (4). In addition, adoption of prophylactic vaccines has been slow. Therefore, understanding of early events that occur upon HPV infection would be important in developing additional modalities for preventing HPV-associated malignancies. This review presents recent advances in our knowledge of the impact of epithelial danger sensing and cytokine responses on the clearance of HPV infections and the emerging role of keratinocytes (KC) as initiators of and partners in the amplification of anti-HPV immunity. HPV INFECTION AND DISEASE PROGRESSIONThe site of infection matters. HPV can be divided into cutaneous and mucosal types based on their tropism for the epithelium of different tissues (5). Mucosal HPV types are further divided into low-and high-risk categories, depending on oncogenicity. Highrisk HPV types cause virtually all cases of cervical cancer (1, 2) and are commonly associated with cancer and high-grade precursor lesions in other mucosal tissues (5-7). HPV16 and -18 cause approximately 70% of cervical cancers, while low-risk HPV6 and -11 cause 90% of anogenital warts. Although HPV broadly infects proliferative cells of cutaneous and mucosal epithelia (2), the risk of HPV-associated disease progression is much higher in the metaplastic transformation zones of the cervix, anus, and oropharynx (8). Active metaplasi...
The unique physiology and function of neurons create differences in their cellular physiology, including their regulation of gene expression. We began several years ago exploring the relationships between the NFκB transcription factor, neuronal survival, and glutamate receptor activation in telencephalic neurons. These studies led us to conclude that this population of cells is nearly incapable of activating the NFκB that is nonetheless expressed at reasonable levels. A subset of the κB cis elements are instead bound by members of the Sp1 family in neurons. Also surprising was our discovery that Sp1 itself, typically described as ubiquitous, is severely restricted in expression within forebrain neurons; Sp4 seems to be substituted during neuronal differentiation. These findings and their implications for neuronal differentiation -as well as potential dedifferentiation during degenerative processes -are discussed here. NFκB induction pathwaysNFκB consists of two subunits of Rel-family proteins, which include RelA (p65), RelB, cRel, p50, and p52 in mammalian cells [1]. RelA, RelB, and cRel subunits contain a transactivation domain; p50 and p52 do not. These subunits can form about a dozen different homo-and heterodimers. The best-characterized dimer is RelA/p50, also known as the canonical NFκB. Rel family proteins have a nuclear localization sequence (NLS) that permits their translocation to the nucleus upon activation, where they bind specific DNA sequences. The consensus bound by canonical NFκB is typically represented by GGGRN-NYYCC; other dimers have slightly different preferences [2]. NFκB activation is transient in most scenarios and terminated through the interaction between NFκB and the inhibitory κB proteins (IκBs) and also through degradation by proteasomal activity in the nucleus [3]. IκBs can mask the NLS of Rel proteins, and one of them (IκBα) has a nuclear export sequence (NES) through which the NFκB/IκBα complex is efficiently shuttled back to cytosol, restoring the inactive state. NFκB activation typically results from the breakdown of IκB proteins, an event requiring multiple steps. Once a stimulus activates the pathway, IκB kinases IKK1, IKK2, and IKK3 (the last is a scaffolding protein) are activated, phosphorylating IκBs [4]. Phosphorylated IκBs are degraded through the ubiquitin/proteasome pathway. The degradation of IκBs liberates NFκB and completes the activation cycle.
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