Summary Recent epidemiological studies have revealed a significant association between periodontitis and oral squamous cell carcinoma (OSCC). Furthermore, matrix metalloproteinase 9 (MMP9) is implicated in the invasion and metastasis of tumor cells. We examined the involvement of Porphyromonas gingivalis, a periodontal pathogen, in OSCC invasion through induced expression of proMMP and its activation. proMMP9 was continuously secreted from carcinoma SAS cells, while P. gingivalis infection increased proenzyme expression and subsequently processed it to active MMP9 in culture supernatant, which enhanced cellular invasion. In contrast, Fusobacterium nucleatum, another periodontal organism, failed to demonstrate such activities. The effects of P. gingivalis were observed with highly invasive cells, but not with the low invasive type. P. gingivalis also stimulated proteinase-activated receptor 2 (PAR2) and enhanced proMMP9 expression, which promoted cellular invasion. P. gingivalis mutants deficient in gingipain proteases failed to activate MMP9. Infected SAS cells exhibited activation of ERK1/2, p38, and NF-kB, and their inhibitors diminished both proMMP9-overexpression and cellular invasion. Together, our results show that P. gingivalis activates the ERK1/2-Ets1, p38/HSP27, and PAR2/NFκB pathways to induce proMMP9 expression, after which the proenzyme is activated by gingipains to promote cellular invasion of OSCC cell lines. These findings suggest a novel mechanism of progression and metastasis of OSCC associated with periodontitis.

BackgroundOral functions are known to decline with aging. However, there is limited evidence that supports the relationship between oral health and frailty. This study aimed to clarify the relationship between oral hygiene conditions, measured by remaining teeth and mucosa, and frailty among elderly people dwelling in a Japanese rural community.MethodsWe surveyed self-reliant elderly individuals aged ≥65 years who were dwelling in the Sasayama-Tamba area of Hyogo, Japan. Frailty was evaluated according to the total score of the Kihon Checklist (KCL). Based on the KCL score, elderly participants were divided into three groups: robust, pre-frail, and frail. The items measured to evaluate oral environment included the number of remaining teeth, denture usage condition, oral hygiene status, dry mouth condition, and salivary bacterial count. For statistical analysis, Fisher’s exact test, one-way analysis of variance, and multiple comparison technique were used.ResultsOf 308 elderly participants, 203 (65.9%), 85 (27.6%), and 20 (6.5%) belonged to the robust, pre-frail, and frail groups, respectively. The proportion of participants who were judged to have poor hygiene was significantly higher in the frail group than in the other two groups. The bacterial count was significantly smaller in the frail group than in the robust group, and the frail group had fewer number of remaining teeth than the other two groups, suggesting that the number of remaining teeth may be associated with bacterial count.ConclusionIn elderly adults, physical frailty may affect the oral hygiene status and condition of the remaining teeth.

ABSTRACTEpidemiological and interventional studies of humans have revealed a close association between periodontal diseases and preterm delivery of low-birth-weight infants.Porphyromonas gingivalis, a periodontal pathogen, can translocate to gestational tissues following oral-hematogenous spread. We previously reported thatP. gingivalisinvades extravillous trophoblast cells (HTR-8) derived from the human placenta and inhibits proliferation through induction of arrest in the G1phase of the cell cycle. The purpose of the present study was to identify signaling pathways mediating cellular impairment caused byP. gingivalis. FollowingP. gingivalisinfection, the expression of Fas was induced and p53 accumulated, responses consistent with response to DNA damage. Ataxia telangiectasia- and Rad3-related kinase (ATR), an essential regulator of DNA damage checkpoints, was shown to be activated together with its downstream signaling molecule Chk2, while the p53 degradation-related protein MDM2 was not induced. The inhibition of ATR prevented both G1arrest and apoptosis caused byP. gingivalisin HTR-8 cells. In addition, small interfering RNA (siRNA) knockdown of p53 abrogated both G1arrest and apoptosis. The regulation of apoptosis was associated with Ets1 activation. HTR-8 cells infected withP. gingivalisexhibited activation of Ets1, and knockdown of Ets1 with siRNA diminished both G1arrest and apoptosis. These results suggest thatP. gingivalisactivates cellular DNA damage signaling pathways that lead to G1arrest and apoptosis in trophoblasts.

Purpose: Survivin is one of the apoptosis inhibitor genes and is rarely expressed in adult ­tissues. However, survivin expression has been detected in various human cancers and ­correlations have been recognized between the level of expression of this gene in tumors and prognosis. In this study, we investigated the correlations between survivin mRNA expres­sion in osteosarcoma tissues and clinicopathological parameters.Methods: There were 22 osteosarcoma patients in our hospital with paraffin-embedded ­tissues which could be extracted from biopsy specimens. We used the RT-PCR method after extracting total RNA and conducted a densitometric analysis to determine the ratio of survivin relative to h-GAPDH as an internal marker.Results: Expression of survivin mRNA was detected in all osteosarcoma samples. Patients with metastasis had high survivin mRNA levels in initial biopsy specimens (p<0.01). Moreover, there was a statistically significant difference in survivin mRNA expression between ­patients with and without metastasis (p<0.01).Conclusion: We concluded that high levels of survivin mRNA expression suggest poor prognosis for osteosarcoma patients.