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BACKGROUND: A laparoscopy-based scoring system was developed by Fagotti et al (Fagotti or Predictive Index Value (PIV)score) based on the intraoperative presence or absence of carcinomatosis on predefined sites. Later, the authors updated the PIV score calculated only in the absence of one or both absolute criteria of non-resectability (mesenteric retraction and miliary carcinomatosis of the small bowel) (updated PIV model). OBJECTIVE: The aim was to demonstrate the non-inferiority of ultrasound to other imaging methods (contrast enhanced computed tomography (CT) and whole-body diffusion-weighted (WB DWI)/MRI) in predicting non-resectable tumor (defined as residual disease>1 cm) using the updated PIV model in patients with tubo-ovarian cancer. The agreement between imaging and intraoperative findings as a reference was also calculated. STUDY DESIGN: This was a European prospective multicenter observational study. We included patients with suspected tubo-ovarian carcinoma who underwent preoperative staging and prediction of non-resectability at ultrasound, CT, WB-DWI/MRI and surgical exploration. The predictors of non-resectability were suspicious mesenteric retraction and/or miliary carcinomatosis of the small bowel or if absent, a PIV>8 (updated PIV model). The PIV score ranges from 0 to 12 according to the presence of disease in six predefined intra-abdominal sites (great omentum, liver surface, lesser omentum/stomach/spleen, parietal peritoneum, diaphragms, bowel serosa/mesentery). The reference standard was surgical outcome, in terms of residual disease>1 cm, assessed by laparoscopy and/or laparotomy. The area under the receiver operating characteristic curve (AUC) to assess the performance of the methods in predicting non-resectability was reported. Concordance between index tests at detection of disease at six predefined sites and intraoperative exploration as reference standard was also calculated using Cohen's kappa. RESULTS: The study was between 2018 and 2022 in five European gynecological oncology centers. Data from 242 patients having both mandatory index tests (ultrasound and CT) were analyzed. 145/242 (59.9%) patients had no macroscopic residual tumor after surgery (R0) (5/145 laparoscopy and 140/145 laparotomy) and 17/242 (7.0%) had residual tumor ≤1cm (R1) (laparotomy). In 80/242 patients (33.1%), the residual tumor was >1 cm (R2), 30 of them underwent laparotomy and maximum surgery was carried out and 50/80 underwent laparoscopy and cytoreduction was not feasible in all of them. After excluding 18/242 (7.4%) patients operated on but not eligible for extensive surgery, the predictive performance of three imaging methods was analyzed in 167 women. The AUCs of all methods in discriminating between resectable and non-resectable tumor was 0.80 for ultrasound, 0.76 for CT, 0.71 for WB-DWI/MRI and 0.90 for surgical exploration. Ultrasound had the highest agreement (Cohen's kappa ranging from 0.59 to 0.79) compared to CT and WB-DWI/MRI to assess all parameters included in the updated PIV model. CONCLUSIONS: Ultrasound showed non-inferiority to CT and to WB-DWI/MRI in discriminating between resectable and non-resectable tumor using the updated PIV model. Ultrasound had the best agreement between imaging and intraoperative findings in the assessment of parameters included in the updated PIV model. Ultrasound is an acceptable method to assess abdominal disease and predict non-resectability in patients with tubo-ovarian cancer in the hands of specially trained ultrasound examiners.
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BACKGROUND: In addition to the diagnostic accuracy of imaging methods, patient-reported satisfaction with imaging methods is important. OBJECTIVE: To report a secondary outcome of the prospective international multicenter Imaging Study in Advanced ovArian Cancer (ISAAC Study), detailing patients' experience with abdomino-pelvic ultrasound, whole-body contrast-enhanced computed tomography (CT), and whole-body diffusion-weighted magnetic resonance imaging (WB-DWI/MRI) for pre-operative ovarian cancer work-up. METHODS: In total, 144 patients with suspected ovarian cancer at four institutions in two countries (Italy, Czech Republic) underwent ultrasound, CT, and WB-DWI/MRI for pre-operative work-up between January 2020 and November 2022. After having undergone all three examinations, the patients filled in a questionnaire evaluating their overall experience and experience in five domains: preparation before the examination, duration of examination, noise during the procedure, radiation load of CT, and surrounding space. Pain perception, examination-related patient-perceived unexpected, unpleasant, or dangerous events ('adverse events'), and preferred method were also noted. RESULTS: Ultrasound was the preferred method by 49% (70/144) of responders, followed by CT (38%, 55/144), and WB-DWI/MRI (13%, 19/144) (p<0.001). The poorest experience in all domains was reported for WB-DWI/MRI, which was also associated with the largest number of patients who reported adverse events (eg, dyspnea). Patients reported higher levels of pain during the ultrasound examination than during CT and WB-DWI/MRI (p<0.001): 78% (112/144) reported no pain or mild pain, 19% (27/144) moderate pain, and 3% (5/144) reported severe pain (pain score >7 of 10) during the ultrasound examination. We did not identify any factors related to patients' preferred method. CONCLUSION: Ultrasound was the imaging method preferred by most patients despite being associated with more pain during the examination in comparison with CT and WB-DWI/MRI. TRIAL REGISTRATION NUMBER: NCT03808792.
Subject(s)
Diffusion Magnetic Resonance Imaging , Ovarian Neoplasms , Patient Satisfaction , Tomography, X-Ray Computed , Ultrasonography , Humans , Female , Ovarian Neoplasms/diagnostic imaging , Ovarian Neoplasms/pathology , Prospective Studies , Middle Aged , Diffusion Magnetic Resonance Imaging/methods , Cross-Sectional Studies , Ultrasonography/methods , Aged , Tomography, X-Ray Computed/methods , Adult , Neoplasm Staging , Whole Body Imaging/methods , Aged, 80 and over , Preoperative Care/methodsABSTRACT
Renal cell carcinoma (RCC) is a common malignancy frequently diagnosed at the metastatic stage. We performed a comprehensive analysis of the tumor immune microenvironment (TIME) in RCC patients, including the peritumoral tissue microenvironment, to characterize the phenotypic patterns and functional characteristics of infiltrating immune cells. T cells from various compartments (peripheral blood, tumor, peritumoral area, and adjacent healthy renal tissue) were assessed using flow cytometry and Luminex analyses, both before and after T cell-specific stimulation, to evaluate activation status and migratory potential. Our findings demonstrated that tumor-infiltrating lymphocytes (TILs) exhibited heightened cytokine production compared to peritumoral T cells (pTILs), acting as the primary source of cytotoxic markers (IFN-γ, granzyme B, and FasL). CD8+ T cells primarily employed Fas Ligand for cytotoxicity, while CD4+ T cells relied on CD107a. In addition, a statistically significant negative correlation between patient mortality and the presence of CD4+CD107+ pTILs was demonstrated. The engagement with the PD-1/PD-L1 pathway was also more evident in CD4+ and CD8+ pTILs as opposed to TILs. PD-L1 expression in the non-leukocyte fraction of the tumor tissue was relatively lower than in their leukocytic counterparts and upon stimulation, peripheral blood T cells displayed much stronger responses to stimulation than TILs and pTILs. Our results suggest that tumor and peritumoral T cells exhibit limited responsiveness to additional activation signals, while peripheral T cells retain their capacity to respond to stimulatory signals.
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OBJECTIVE: The "intermediate-risk" (IR) group of early-stage cervical cancer patients is characterized by negative pelvic lymph nodes and a combination of tumor-related prognostic risk factors such as tumor size ≥2 cm, lymphovascular space invasion (LVSI), and deep stromal invasion. However, the role of adjuvant treatment in these patients remains controversial. We investigated whether adjuvant (chemo)radiation is associated with a survival benefit after radical surgery in patients with IR cervical cancer. METHODS: We analyzed data from patients with IR cervical cancer (tumor size 2-4 cm plus LVSI OR tumor size >4 cm; N0; no parametrial invasion; clear surgical margins) who underwent primary curative-intent surgery between 2007 and 2016 and were retrospectively registered in the international multicenter Surveillance in Cervical CANcer (SCCAN) study. RESULTS: Of 692 analyzed patients, 274 (39.6%) received no adjuvant treatment (AT-) and 418 (60.4%) received radiotherapy or chemoradiotherapy (AT+). The 5-year disease-free survival (83.2% and 80.3%; PDFS = 0.365) and overall survival (88.7% and 89.0%; POS = 0.281) were not significantly different between the AT- and AT+ groups, respectively. Adjuvant (chemo)radiotherapy was not associated with a survival benefit after adjusting for confounding factors by case-control propensity score matching or in subgroup analyses of patients with tumor size ≥4 cm and <4 cm. In univariable analysis, adjuvant (chemo)radiotherapy was not identified as a prognostic factor in any of the subgroups (full cohort: PDFS = 0.365; POS = 0.282). CONCLUSION: Among patients with IR early-stage cervical cancer, radical surgery alone achieved equal disease-free and overall survival rates to those achieved by combining radical surgery with adjuvant (chemo)radiotherapy.
Subject(s)
Uterine Cervical Neoplasms , Female , Humans , Uterine Cervical Neoplasms/pathology , Neoplasm Staging , Hysterectomy , Combined Modality Therapy , Prognosis , Radiotherapy, Adjuvant , Retrospective StudiesABSTRACT
BACKGROUND: In cervical cancer, presence of lymph-node macrometastases (MAC) is a major prognostic factor and an indication for adjuvant treatment. However, since clinical impact of micrometastases (MIC) and isolated tumor-cells (ITC) remains controversial, we sought to identify a cut-off value for the metastasis size not associated with negative prognosis. METHODS: We analyzed data from 967 cervical cancer patients (T1a1L1-T2b) registered in the SCCAN (Surveillance in Cervical CANcer) database, who underwent primary surgical treatment, including sentinel lymph-node (SLN) biopsy with pathological ultrastaging. The size of SLN metastasis was considered a continuous variable and multiple testing was performed for cut-off values of 0.01-1.0 mm. Disease-free survival (DFS) was compared between N0 and subgroups of N1 patients defined by cut-off ranges. RESULTS: LN metastases were found in 172 (18%) patients, classified as MAC, MIC, and ITC in 79, 54, and 39 patients, respectively. DFS was shorter in patients with MAC (HR 2.20, P = 0.003) and MIC (HR 2.87, P < 0.001), while not differing between MAC/MIC (P = 0.484). DFS in the ITC subgroup was neither different from N0 (P = 0.127) nor from MIC/MAC subgroups (P = 0.449). Cut-off analysis revealed significantly shorter DFS compared to N0 in all subgroups with metastases ≥0.4 mm (HR 2.311, P = 0.04). The significance of metastases <0.4 mm could not be assessed due to limited statistical power (<80%). We did not identify any cut-off for the size of metastasis with significantly better prognosis than the rest of N1 group. CONCLUSIONS: In cervical cancer patients, the presence of LN metastases ≥0.4 mm was associated with a significant negative impact on DFS and no cut-off value for the size of metastasis with better prognosis than N1 was found. Traditional metastasis stratification based on size has no clinical implication.
Subject(s)
Breast Neoplasms , Sentinel Lymph Node , Uterine Cervical Neoplasms , Female , Humans , Lymphatic Metastasis/pathology , Neoplasm Micrometastasis/pathology , Uterine Cervical Neoplasms/surgery , Uterine Cervical Neoplasms/pathology , Sentinel Lymph Node Biopsy , Lymph Nodes/pathology , Neoplasm Staging , Breast Neoplasms/pathology , Sentinel Lymph Node/pathologyABSTRACT
BACKGROUND: The role of adjuvant treatment in the intermediate-risk group of patients with early-stage cervical cancer is controversial and is supported by a single randomized Gynecologic Oncology Group (GOG) 92 study performed more than 20 years ago. Recent retrospective studies have shown excellent local control in this group of patients after radical surgery with no additional adjuvant treatment. PRIMARY OBJECTIVE: To evaluate if adjuvant (chemo)radiation is associated with a survival benefit after radical surgery in patients with intermediate-risk cervical cancer. STUDY HYPOTHESIS: Radical surgery alone is non-inferior to the combined treatment of radical surgery followed by adjuvant (chemo)radiation in disease-free survival in patients with intermediate-risk cervical cancer. TRIAL DESIGN: This is a phase III, international, multicenter, randomized, non-inferiority trial in which patients with intermediate-risk cervical cancer will be randomized 1:1 into arm A, with no additional treatment after radical surgery, and arm B, receiving adjuvant external beam radiotherapy±brachytherapy ± concomitant chemotherapy. Patient data will be collected over 3 years post-randomization of the last enrolled patient for primary endpoint analysis or for 6 years for the overall survival analysis. MAJOR INCLUSION/EXCLUSION CRITERIA: Patients with intermediate-risk early-stage cervical cancer (IB1-IIA), defined as lymph node-negative patients with a combination of negative prognostic factors (tumor size >4 cm; tumor size >2 cm and lymphovascular space invasion; deep stromal invasion >2/3; or tumor-free distance <3 mm) with squamous cell carcinoma or human papillomavirus (HPV)-related adenocarcinoma, are eligible for the trial. PRIMARY ENDPOINT: Disease-free survival defined as time from randomization to recurrence diagnosis. SAMPLE SIZE: 514 patients from up to 90 sites will be randomized. ESTIMATED DATES FOR COMPLETING ACCRUAL AND PRESENTING RESULTS: It is estimated that the accrual will be completed by 2027 (with 3 additional years of follow-up) and primary endpoint results will be published by 2031. Estimated trial completion is by 2034. TRIAL REGISTRATION: NCT04989647.
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This is a case report of a rare finding of an extragonadal yolk sac tumor in a 37-year-old patient who presented with shortness of breath and abdominal bloating. During imaging and staging surgery, the findings were strongly suggestive of an extragonadal advanced tumor presenting with peritoneal dissemination, predominantly affecting omentum, with no clear primary origin. Histology revealed an extragonadal yolk sac tumor in a pure form outside the ovaries. Lacking an obvious origin elsewhere, the tumor was highly suspected to have truly originated from the omentum. The patient underwent surgery and four cycles of chemotherapy consisting of cisplatin, etoposide, and bleomycin. One-year outpatient follow-up thereafter showed no relapse. We herein discuss a possible site of the tumor origin and its development, as well as diagnostic challenges and disease prognosis.
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BACKGROUND: Lower limb lymphoedema (LLL) is the most disabling adverse effect of surgical staging of pelvic lymph nodes. However, the lack of standardisation of volumetric LLL assessment hinders direct comparison between the studies and makes LLL reporting unreliable. The aim of our study is to report outcomes from a prospective trial that have implications for LLL assessment standardisation. METHODS: In the prospective international multicentre trial SENTIX, a group of 150 patients with stage IA1-IB2 cervical cancer treated by uterine surgery with bilateral sentinel lymph node biopsy was prospectively evaluated by objective LLL assessment, based on limb volume change (LVC) using circumferrential limb measurements and subjective patient-reported swelling. The assessments were conducted in six-month periods over 24 months post-surgery. RESULTS: Patient LVC substantially fluctuated in both positive and negative directions, which were comparable in frequency up to ±14% change. Thirty-eight patients experienced persistent LVC increase >10% classified as LLL, with nine months median time to onset. Some 34.2% of cases experienced onset later than one year after the surgery. Thirty-three patients (22%) experienced transient oedema characterised as LVC >10%, which resolved without intervention between two consequent follow-up visits. No significant correlation between LVC >10% and a patient-reported swelling was observed. CONCLUSIONS: Given that we observed comparable fluctuations of the the lower-limb volumes after surgical treatment of cervical cancer in both positive and negative direction up to ±14%, the diagnostic threshold for LLL diagnosis based on LVC should be increased to >15% LVC. The distinction of transient oedema from persistent LLL requires repeated measurements. Also, as one-third of LLL cases are diagnosed >1-year post-surgery, a sufficient follow-up duration needs to be ensured. Patient-reported swelling correlated poorly with LVC and should only be used as an adjunct to objective LLL assessment. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02494063.
Subject(s)
Decision Making , Lymphedema/pathology , Neoplasm Staging , Uterine Cervical Neoplasms/pathology , Adult , Europe , Female , Humans , Lower Extremity , Prospective Studies , Sentinel Lymph Node Biopsy , South AfricaABSTRACT
BACKGROUND: Up to 26% of patients with early-stage cervical cancer experience relapse after primary surgery. However, little is known about which factors influence prognosis following disease recurrence. Therefore, our aims were to determine post-recurrence disease-specific survival (PR-DSS) and to identify respective prognostic factors for PR-DSS. METHODS: Data from 528 patients with early-stage cervical cancer who relapsed after primary surgery performed between 2007 and 2016 were obtained from the SCANN study (Surveillance in Cervical CANcer). Factors related to the primary disease and recurrence were combined in a multivariable Cox proportional hazards model to predict PR-DSS. RESULTS: The 5-year PR-DSS was 39.1% (95% confidence interval [CI] 22.7%-44.5%), median disease-free interval between primary surgery and recurrence (DFI1) was 1.5 years, and median survival after recurrence was 2.5 years. Six significant variables were identified in the multivariable analysis and were used to construct the prognostic model. Two were related to primary treatment (largest tumour size and lymphovascular space invasion) and four to recurrence (DFI1, age at recurrence, presence of symptoms, and recurrence type). The C-statistic after 10-fold cross-validation of prognostic model reached 0.701 (95% CI 0.675-0.727). Three risk-groups with significantly differing prognoses were identified, with 5-year PR-DSS rates of 81.8%, 44.6%, and 12.7%. CONCLUSIONS: We developed the robust model of PR-DSS to stratify patients with relapsed cervical cancer according to risk profiles using six routinely recorded prognostic markers. The model can be utilised in clinical practice to aid decision-making on the strategy of recurrence management, and to better inform the patients.
Subject(s)
Adenocarcinoma/mortality , Carcinoma, Adenosquamous/mortality , Carcinoma, Neuroendocrine/mortality , Carcinoma, Squamous Cell/mortality , Neoplasm Recurrence, Local/mortality , Uterine Cervical Neoplasms/mortality , Adenocarcinoma/pathology , Adenocarcinoma/physiopathology , Adenocarcinoma/therapy , Adult , Asymptomatic Diseases , Carcinoma, Adenosquamous/pathology , Carcinoma, Adenosquamous/physiopathology , Carcinoma, Adenosquamous/therapy , Carcinoma, Neuroendocrine/pathology , Carcinoma, Neuroendocrine/physiopathology , Carcinoma, Neuroendocrine/therapy , Carcinoma, Squamous Cell/pathology , Carcinoma, Squamous Cell/physiopathology , Carcinoma, Squamous Cell/therapy , Chemotherapy, Adjuvant , Female , Humans , Hysterectomy , Lymph Nodes/pathology , Middle Aged , Multivariate Analysis , Neoplasm Recurrence, Local/pathology , Neoplasm Recurrence, Local/physiopathology , Neoplasm Recurrence, Local/therapy , Neoplasm Staging , Prognosis , Proportional Hazards Models , Radiotherapy, Adjuvant , Survival Rate , Trachelectomy , Tumor Burden , Uterine Cervical Neoplasms/pathology , Uterine Cervical Neoplasms/physiopathology , Uterine Cervical Neoplasms/therapyABSTRACT
PURPOSE: Current guidelines for surveillance strategy in cervical cancer are rigid, recommending the same strategy for all survivors. The aim of this study was to develop a robust model allowing for individualised surveillance based on a patient's risk profile. METHODS: Data of 4343 early-stage patients with cervical cancer treated between 2007 and 2016 were obtained from the international SCCAN (Surveillance in Cervical Cancer) consortium. The Cox proportional hazards model predicting disease-free survival (DFS) was developed and internally validated. The risk score, derived from regression coefficients of the model, stratified the cohort into significantly distinctive risk groups. On its basis, the annual recurrence risk model (ARRM) was calculated. RESULTS: Five variables were included in the prognostic model: maximal pathologic tumour diameter; tumour histotype; grade; number of positive pelvic lymph nodes; and lymphovascular space invasion. Five risk groups significantly differing in prognosis were identified with a five-year DFS of 97.5%, 94.7%, 85.2% and 63.3% in increasing risk groups, whereas a two-year DFS in the highest risk group equalled 15.4%. Based on the ARRM, the annual recurrence risk in the lowest risk group was below 1% since the beginning of follow-up and declined below 1% at years three, four and >5 in the medium-risk groups. In the whole cohort, 26% of recurrences appeared at the first year of the follow-up, 48% by year two and 78% by year five. CONCLUSION: The ARRM represents a potent tool for tailoring the surveillance strategy in early-stage patients with cervical cancer based on the patient's risk status and respective annual recurrence risk. It can easily be used in routine clinical settings internationally.
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BACKGROUND: To prospectively assess LLL incidence among cervical cancer patients treated by uterine surgery complemented by SLN biopsy, without PLND. METHODS: A prospective study in 150 patients with stage IA1-IB2 cervical cancer treated by uterine surgery with bilateral SLN biopsy. Objective LLL assessments, based on limb volume increase (LVI) between pre- and postoperative measurements, and subjective patient-perceived swelling were conducted in six-month periods over 24-months post-surgery. RESULTS: The cumulative incidence of LLL at 24 months was 17.3% for mild LLL (LVI 10-19%), 9.2% for moderate LLL (LVI 20-39%), while only one patient (0.7%) developed severe LLL (LVI > 40%). The median interval to LLL onset was nine months. Transient edema resolving without intervention within six months was reported in an additional 22% of patients. Subjective LLL was reported by 10.7% of patients, though only a weak and partial correlation between subjective-report and objective-LVI was found. No risk factor directly related to LLL development was identified. CONCLUSIONS: The replacement of standard PLND by bilateral SLN biopsy in the surgical treatment of cervical cancer does not eliminate the risk of mild to moderate LLL, which develops irrespective of the number of SLN removed.
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BACKGROUND: Models predicting recurrence risk (RR) of cervical cancer are used to tailor adjuvant treatment after radical surgery. The goal of our study was to compare available prognostic factors and to develop a prognostic model that would be easy to standardise and use in routine clinical practice. METHODS: All consecutive patients with early-stage cervical cancer treated by primary surgery in a single referral centre (01/2007-12/2016) were eligible if assessed by standardised protocols for pre-operative imaging and pathology. Fifteen prognostic markers were evaluated in 379 patients, out of which 320 lymph node (LN)-negative. RESULTS: The best predictive model for the whole cohort entailed a combination of tumour-free distance (TFD) ≤ 3.5 mm and LN positivity, which separated two subgroups with a substantially distinct RR 36% and 6.5%, respectively. In LN-negative patients, a combination of TFD ≤ 3.5 mm and adenosquamous tumour type separated a group of nine patients with RR 33% from the rest of the group with 6% RR. CONCLUSIONS: A newly identified prognostic marker, TFD, surpassed all traditional tumour-related markers in the RR assessment. Predictive models combining TFD, which can be easily accessed on pre-operative imaging, with LN status or tumour type can be used in daily practice and can help to identify patients with the highest RR.
Subject(s)
Adenocarcinoma/pathology , Carcinoma, Squamous Cell/pathology , Lymph Nodes/pathology , Neoplasm Recurrence, Local/pathology , Uterine Cervical Neoplasms/pathology , Adenocarcinoma/surgery , Adult , Aged , Carcinoma, Squamous Cell/surgery , Female , Follow-Up Studies , Humans , Hysterectomy , Lymph Nodes/surgery , Middle Aged , Neoplasm Recurrence, Local/surgery , Prognosis , Retrospective Studies , Survival Rate , Uterine Cervical Neoplasms/surgeryABSTRACT
Ecosystems worldwide are exposed to pollutants connected to the industrial production of pharmaceuticals. The objective of this study was to study the composition and characteristics of the soil microbial communities that had been exposed to long-term selection pressure caused by the industrial production of penicillin G. Soil samples from four sites among the penicillin G production plant were analysed using 16S rRNA profiling via Illumina MiSeq platform and were compared with the control samples from four sites outside the plant. Total metagenomic DNA from the impacted soil was also used for the preparation of E. coli T1R-based fosmid library which was consequently qualitatively tested for the presence of penicillin G acylase (PGA)-encoding genes using the method of sequence homology. Analyses of alpha diversity revealed that the long-term antibiotic presence in the soil significantly increased the microbial diversity and richness in terms of Shannon diversity index (p = 0.002) and Chao estimates (p = 0.004). Principal component analysis showed that the two types of communities (on-site and control) could be separated at the phylum, class and genus level. The on-site soil was enriched in Betaproteobacteria, Deltaproteobacteria, Gemmatimonadetes, Acidobacteria and Planctomycetia, while a significant decrease in Actinobacteria was observed. Metagenomic fosmid library revealed high hit rates in identifying PGAs (14 different genes identified) and confirmed the biotechnological potential of soils impacted by anthropogenic activity. This study offers new insights into the changes in microbial communities of soils exposed to anthropogenic activity as well as indicates that those soils may represent a hotspot for biotechnologically interesting targets.
Subject(s)
Anti-Bacterial Agents/biosynthesis , Bacteria/classification , Bacteria/metabolism , Microbiota , Soil Microbiology , Bacteria/genetics , Bacteria/isolation & purification , Biodiversity , DNA, Bacterial/genetics , Escherichia coli/genetics , Industrial Microbiology , Metagenome , Metagenomics , Microbiota/genetics , Phylogeny , RNA, Ribosomal, 16S/genetics , Soil , Soil PollutantsABSTRACT
To take full advantage of recombinant Pichia pastoris (Komagataella phaffii) as a production system for heterologous proteins, the complex protein secretory process should be understood and optimised by circumventing bottlenecks. Typically, little or no attention has been paid to the fate of newly synthesised protein inside the cell, or its passage through the secretory pathway, and only the secreted product is measured. However, the system's productivity (i.e. specific production rate qp), includes productivity of secreted (qp,extra) plus intracellularly accumulated (qp,intra) protein. In bioreactor cultivations with P. pastoris producing penicillin G acylase, we studied the dynamics of product formation, i.e. both the specific product secretion (qp,extra) and product retention (qp,intra) as functions of time, as well as the kinetics, i.e. productivity in relation to specific growth rate (µ). Within the time course, we distinguished (I) an initial phase with constant productivities, where the majority of product accumulated inside the cells, and qp,extra, which depended on µ in a bell-shaped manner; (II) a transition phase, in which intracellular product accumulation reached a maximum and productivities (intracellular, extracellular, overall) were changing; (III) a new phase with constant productivities, where secretion prevailed over intracellular accumulation, qp,extra was linearly related to µ and was up to three times higher than in initial phase (I), while qp,intra decreased 4-6-fold. We show that stress caused by heterologous protein production induces cellular imbalance leading to a secretory bottleneck that ultimately reaches equilibrium. This understanding may help to develop cultivation strategies for improving protein secretion from P. pastoris.Key Points⢠A novel concept for industrial bioprocess development.⢠A Relationship between biomass growth and product formation in P. pastoris.⢠A Three (3) phases of protein production/secretion controlled by the AOX1-promoter.⢠A Proof of concept in production of industrially relevant penicillin G acylase.
Subject(s)
Bacterial Proteins/metabolism , Penicillin Amidase/metabolism , Saccharomycetales/metabolism , Bacterial Proteins/genetics , Batch Cell Culture Techniques , Biomass , Bioreactors , Extracellular Space/metabolism , Intracellular Space/metabolism , Kinetics , Models, Theoretical , Penicillin Amidase/genetics , Promoter Regions, Genetic , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Saccharomycetales/genetics , Saccharomycetales/growth & developmentABSTRACT
Pichia pastoris (Komagataella sp.) is broadly used for the production of secreted recombinant proteins. Due to the high rate of protein production, incorrectly folded proteins may accumulate in the endoplasmic reticulum (ER). To restore their proper folding, the cell triggers the unfolded protein response (UPR); however, if the proteins cannot be repaired, they are degraded, which impairs process productivity. Moreover, a non-producing/non-secreting subpopulation of cells might occur, which also decreases overall productivity. Therefore, an in depth understanding of intracellular protein fluxes and population heterogeneity is needed to improve productivity. Under industrially relevant cultivation conditions in bioreactors, we cultured P. pastoris strains producing three different recombinant proteins: penicillin G acylase from Escherichia coli (EcPGA), lipase B from Candida antarctica (CaLB) and xylanase A from Thermomyces lanuginosus (TlXynA). Extracellular and intracellular product concentrations were determined, along with flow cytometry-based single-cell measurements of cell viability and the up-regulation of UPR. The cell population was distributed into four clusters, two of which were viable cells with no UPR up-regulation, differing in cell size and complexity. The other two clusters were cells with impaired viability, and cells with up-regulated UPR. Over the time course of cultivation, the distribution of the population into these four clusters changed. After 30 h of production, 60% of the cells producing EcPGA, which accumulated in the cells (50-70% of the product), had up-regulated UPR, but only 13% of the cells had impaired viability. A higher proportion of cells with decreased viability was observed in strains producing CaLB (20%) and TlXynA (27%). The proportion of cells with up-regulated UPR in CaLB-producing (35%) and TlXynA-producing (30%) strains was lower in comparison to the EcPGA-producing strain, and a smaller proportion of CaLB and TlXynA (<10%) accumulated in the cells. These data provide an insight into the development of heterogeneity in a recombinant P. pastoris population during a biotechnological process. A deeper understanding of the relationship between protein production/secretion and the regulation of the UPR might be utilized in bioprocess control and optimization with respect to secretion and population heterogeneity.