Modelling Chlamydia and HPV co-infection in patient-derived ectocervix organoids reveals distinct cellular reprogramming

Coinfections with pathogenic microbes continually confront cervical mucosa, yet their implications in pathogenesis remain unclear. Lack of in-vitro models recapitulating cervical epithelium has been a bottleneck to study coinfections. Using patient-derived ectocervical organoids, we systematically modeled individual and coinfection dynamics of Human papillomavirus (HPV)16 E6E7 and Chlamydia, associated with carcinogenesis. The ectocervical stem cells were genetically manipulated to introduce E6E7 oncogenes to mimic HPV16 integration. Organoids from these stem cells develop the characteristics of precancerous lesions while retaining the self-renewal capacity and organize into mature stratified epithelium similar to healthy organoids. HPV16 E6E7 interferes with Chlamydia development and induces persistence. Unique transcriptional and post-translational responses induced by Chlamydia and HPV lead to distinct reprogramming of host cell processes. Strikingly, Chlamydia impedes HPV-induced mechanisms that maintain cellular and genome integrity, including mismatch repair in the stem cells. Together, our study employing organoids demonstrates the hazard of multiple infections and the unique cellular microenvironment they create, potentially contributing to neoplastic progression

Chlamydia Infection Promotes Host DNA Damage and Proliferation but Impairs the DNA Damage Response

SummaryThe obligate intracellular bacterial pathogen Chlamydia trachomatis (Ctr) has been associated with cervical and ovarian cancer development. However, establishment of causality and the underlying mechanisms remain outstanding. Our analysis of Ctr-induced alterations to global host histone modifications revealed distinct patterns of histone marks during acute and persistent infections. In particular, pH2AX (Ser139) and H3K9me3, hallmarks of DNA double-strand breaks (DSBs) and senescence-associated heterochromatin foci (SAHF), respectively, showed sustained upregulation during Ctr infection. Ctr-induced reactive oxygen species were found to contribute to persistent DSBs, which in turn elicited SAHF formation in an ERK-dependent manner. Furthermore, Ctr interfered with DNA damage responses (DDR) by inhibiting recruitment of the DDR proteins pATM and 53BP1 to damaged sites. Despite impaired DDR, Ctr-infected cells continued to proliferate, supported by enhanced oncogenic signals involving ERK, CyclinE, and SAHF. Thus, by perturbing host chromatin, DSB repair, and cell-cycle regulation, Ctr generates an environment favorable for malignant transformation

Concurrent inhibition of PI3K and mTORC1/mTORC2 overcomes resistance to rapamycin induced apoptosis by down-regulation of Mcl-1 in mantle cell lymphoma

Mantle cell lymphoma (MCL) is an aggressive form of Non-Hodgkin-Lymphoma (NHL) with an ongoing need for novel treatments. Apart from the translocation t(11;14), which facilitates constitutive transcription of cyclin D1, additional aberrations are frequently observed in MCL, including a recurrent dysregulation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway. mTOR, a key component of this pathway, is pivotal for the assembly of mTOR complex (mTORC) 1 and 2. Temsirolimus an analog of the mTOR inhibitor rapamycin is approved for the treatment of relapsed MCL. Response rates, however, are low and response durations are short. We demonstrate that inhibition of mTORC1 by rapamycin or blocking of mTORC1 and mTORC2 in conjunction with PI3K by NVP-BEZ235 reduces proliferation of MCL cell lines to a similar extent. However, only NVP-BEZ235 is able to sufficiently inhibit the downstream pathway of mTOR and to mediate cell death through activation of the intrinsic apoptosis pathway. Further analysis demonstrated that the anti-apoptotic Bcl-2 family member Mcl-1 plays a central role in regulation of MCL survival. While Mcl-1 protein levels remained unchanged after co-culture with rapamycin, they were down-regulated in NVP-BEZ235 treated cells. Furthermore, inhibition of Mcl-1 by the BH3-only mimetic obatoclax or down-regulation of constitutive Mcl-1, but not of Bcl-2 or Bcl-xL , by siRNA facilitated cell death of MCL cells and enhanced rapamycin's as well as NVP-BEZ235's capacity to induce cell death. Our findings may help to lay the foundation for further improvements in the treatment of MCL