Mycoplasmal lipoprotein p37 binds human protein HER2

Downregulated mitochondrial transcription factor A enhances mycoplasma infection to promote the metastasis of hepatocellular carcinoma

Mycoplasma is widespread in various hosts and may cause various diseases in animals. Interestingly, the occurrence of mycoplasma infection was observed in many tumor types. However, the mechanism regulating its infection is far from clear. We unexpectedly found that the knockdown of mitochondrial transcription factor A (TFAM) remarkably enhanced mycoplasma infection in hepatocellular carcinoma (HCC) cells. More importantly, we found that mycoplasma infection facilitated by TFAM knockdown significantly promoted HCC cell metastasis. Mycoplasma infection was further found to be positively correlated with poor prognosis in patients with HCC. Mechanistically, the decreased TFAM expression upregulated the transcription factor Sp1 to increase the expression level of Annexin A2 (ANXA2), which was reported to interact with membrane protein of mycoplasma. Moreover, we found that mycoplasma infection enhanced by the TFAM downregulation promoted HCC migration and invasion by activating the nuclear factor-κB signaling pathway. The downregulation of TFAM enhanced mycoplasma infection in HCC cells and promoted HCC cell metastasis. Our study contributes to the understanding of the pathological role of mycoplasma infection and provides supporting evidence that targeting TFAM could be a potential strategy for the treatment of HCC with mycoplasma infection.

Mycoplasma hyorhinis infection promotes tyrosine kinase inhibitor (TKI) resistance in lung adenocarcinoma patients

PURPOSE

To explore the relationship between Mycoplasma hyorhinis infection and tyrosine kinase inhibitor (TKI) resistance in lung adenocarcinoma patients.

METHODS

Mycoplasma hyorhinis infection can be verified with the monoclonal antibody PD4, which specifically recognizes a distinct protein of M. hyorhinis. Immunohistochemistry (IHC), using PD4 to detect M. hyorhinis, was performed on paraffin-embedded lung adenocarcinoma tissues of patients who had epidermal growth factor (EGFR) mutations and had received oral TKI. The number of patients enrolled in our study was 101. Assessments following TKI treatment were performed until objective disease progression or stable disease at the cutoff date was reached. In all of the patients, the primary endpoint was investigator-assessed progression-free survival (PFS).

RESULTS

Immunohistochemistry revealed that 61 of 101 cases (60.4%) of lung adenocarcinoma were positive for M. hyorhinis, which comprised of 31 low-positive cases and 30 high-positive cases; the remaining 40 cases (39.6%) were negative. The median PFS was significantly longer in the negative group [18 months (95% CI 14.15-21.85)] than in the low-positive group [10 months (95% CI 7.70-12.30); hazard ratio (HR) 4.095, 95% CI 2.254-7.438; p < 0.001] and in the high-positive group [4 months (95% CI 2.85-5.15); HR 31.703, 95% CI 14.425-69.678; p < 0.001]. The results of the subgroup analysis were satisfactory. The PFS benefit with negative M. hyorhinis infection was consistent across subgroups.

CONCLUSIONS

In this retrospective, exploratory analysis, M. hyorhinis infection significantly reduced PFS. With increased levels of M. hyorhinis infection, the progression of the disease was more advanced, likely due to the hydrolysis of TKI by M. hyorhinis. A strong correlation was found between M. hyorhinis infection and TKI resistance in lung adenocarcinoma. This study provides potent evidence that M. hyorhinis hydrolyses TKI and will assist in the research of related mechanisms in the future.

IMPLICATIONS FOR CANCER SURVIVORS

It provides an option to improve the efficacy of TKI, including strategies to decrease M. hyorhinis infection, thereby reducing long-term distress in TKI resistance patients with EGFR mutations.

Mycoplasma-associated multidrug resistance of hepatocarcinoma cells requires the interaction of P37 and Annexin A2

Mycoplasma infection has been reported to be associated with cancer migration, invasion, epithelial-mesenchymal transition as well as the resistance to nucleoside analogues chemotherapeutic drugs. In this study, we found that the sensitivity of hepatocarcinoma cells to Cisplatin, Gemcitabine and Mitoxantrone was increased by mycoplasma elimination. Similar to the effect of anti-mycoplasma agent, interrupting the interaction between Mycoplasma hyorhinis membrane protein P37 and Annexin A2 of host cells using the N-terminal of ANXA2 polypeptide enhanced the sensitivity of HCC97L cells to Gemcitabine and Mitoxantrone. Meanwhile, we did not observe any changes in expression or distribution of multidrug resistance associated transporters, ATP-Binding Cassette protein B1, C1 and G2, on the removal of mycoplasma. These results suggest that mycoplasma induces a resistance to multiple drugs in hepatocarcinoma cells which required the interaction of P37 and Annexin A2. The pathway downstream this interaction needs to be explored.